diff --git a/core/src/main/resources/hudson/PluginManager/PluginCycleDependenciesMonitor/message.jelly b/core/src/main/resources/hudson/PluginManager/PluginCycleDependenciesMonitor/message.jelly
index cb20ebf8dfe7..5ccac430ecd2 100644
--- a/core/src/main/resources/hudson/PluginManager/PluginCycleDependenciesMonitor/message.jelly
+++ b/core/src/main/resources/hudson/PluginManager/PluginCycleDependenciesMonitor/message.jelly
@@ -24,7 +24,7 @@ THE SOFTWARE.
 
 <?jelly escape-by-default='true'?>
 <j:jelly xmlns:j="jelly:core" xmlns:st="jelly:stapler" xmlns:d="jelly:define" xmlns:l="/lib/layout" xmlns:t="/lib/hudson" xmlns:f="/lib/form">
-  <div class="jenkins-alert jenkins-alert-danger">
+  <div class="alert alert-danger">
     <dl>
         <dt>${%PluginCycles}</dt>
         <j:forEach var="p" items="${it.pluginsWithCycle}">
diff --git a/core/src/main/resources/hudson/PluginManager/PluginDeprecationMonitor/message.jelly b/core/src/main/resources/hudson/PluginManager/PluginDeprecationMonitor/message.jelly
index 1f5ec400bd3c..45c4cead0a44 100644
--- a/core/src/main/resources/hudson/PluginManager/PluginDeprecationMonitor/message.jelly
+++ b/core/src/main/resources/hudson/PluginManager/PluginDeprecationMonitor/message.jelly
@@ -24,7 +24,7 @@ THE SOFTWARE.
 
 <?jelly escape-by-default='true'?>
 <j:jelly xmlns:j="jelly:core" xmlns:st="jelly:stapler" xmlns:d="jelly:define" xmlns:l="/lib/layout" xmlns:t="/lib/hudson" xmlns:f="/lib/form">
-  <div class="jenkins-alert jenkins-alert-warning">
+  <div class="alert alert-warning">
     <dl>
       <dt>${%DeprecatedPlugins}</dt>
       <j:forEach var="e" items="${it.getDeprecatedPlugins()}">
diff --git a/core/src/main/resources/hudson/PluginManager/PluginUpdateMonitor/message.jelly b/core/src/main/resources/hudson/PluginManager/PluginUpdateMonitor/message.jelly
index b1f9ba193d49..73182ec483e4 100644
--- a/core/src/main/resources/hudson/PluginManager/PluginUpdateMonitor/message.jelly
+++ b/core/src/main/resources/hudson/PluginManager/PluginUpdateMonitor/message.jelly
@@ -24,7 +24,7 @@ THE SOFTWARE.
 
 <?jelly escape-by-default='true'?>
 <j:jelly xmlns:j="jelly:core" xmlns:st="jelly:stapler" xmlns:d="jelly:define" xmlns:l="/lib/layout" xmlns:t="/lib/hudson" xmlns:f="/lib/form">
-  <div class="jenkins-alert jenkins-alert-danger">
+  <div class="alert alert-danger">
     <dl>
         <dt>${%RequiredPluginUpdates}</dt>
         <j:forEach var="p" items="${it.pluginsToBeUpdated}">
diff --git a/core/src/main/resources/hudson/PluginManager/advanced.jelly b/core/src/main/resources/hudson/PluginManager/advanced.jelly
index 81948afa6e80..8d0e6abcd22e 100644
--- a/core/src/main/resources/hudson/PluginManager/advanced.jelly
+++ b/core/src/main/resources/hudson/PluginManager/advanced.jelly
@@ -37,7 +37,7 @@ THE SOFTWARE.
         <l:main-panel>
           <l:app-bar title="${%Advanced settings}"/>
 
-          <div class="jenkins-alert jenkins-alert-info">
+          <div class="alert alert-info">
               <strong>${%proxyMovedBlurb(rootURL+"/manage/configure")}</strong>
           </div>
 
diff --git a/core/src/main/resources/hudson/PluginManager/installed.jelly b/core/src/main/resources/hudson/PluginManager/installed.jelly
index 57679d61ffe3..8013742cf738 100644
--- a/core/src/main/resources/hudson/PluginManager/installed.jelly
+++ b/core/src/main/resources/hudson/PluginManager/installed.jelly
@@ -54,7 +54,7 @@ THE SOFTWARE.
             data-is-restart-required="${app.updateCenter.isRestartRequiredForCompletion()}" />
 
       <j:if test="${app.updateCenter.isRestartRequiredForCompletion()}">
-        <div class="jenkins-alert jenkins-alert-warning"><strong>${%Warning}</strong>: ${%requires.restart}</div>
+        <div class="alert alert-warning"><strong>${%Warning}</strong>: ${%requires.restart}</div>
       </j:if>
 
       <template id="i18n"
@@ -130,7 +130,7 @@ THE SOFTWARE.
                       </div>
                     </j:if>
                     <j:if test="${!p.getActiveWarnings().isEmpty()}">
-                      <div class="jenkins-alert jenkins-alert-danger">${%securityWarning}
+                      <div class="alert alert-danger">${%securityWarning}
                         <ul>
                           <j:forEach var="warning" items="${p.getActiveWarnings()}">
                             <li>
@@ -143,13 +143,13 @@ THE SOFTWARE.
                       </div>
                     </j:if>
                     <j:if test="${p.isDeprecated()}">
-                      <div class="jenkins-alert jenkins-alert-warning">
+                      <div class="alert alert-warning">
                         <!-- figure out a way how to present deprecations by multiple update sites instead of just the first one -->
                         ${%deprecationWarning(p.getDeprecations().get(0).url)}
                       </div>
                     </j:if>
                     <j:if test="${it.hasAdoptThisPluginLabel(p)}">
-                      <div class="jenkins-alert jenkins-alert-warning jenkins-!-margin-top-1 jenkins-!-margin-bottom-0">
+                      <div class="alert alert-warning jenkins-!-margin-top-1 jenkins-!-margin-bottom-0">
                         ${%adoptThisPlugin}
                       </div>
                     </j:if>
@@ -250,7 +250,7 @@ THE SOFTWARE.
                         ${p.name}
                       </div>
                     </j:if>
-                    <div class="jenkins-alert jenkins-alert-danger jenkins-!-margin-top-1 jenkins-!-margin-bottom-0">
+                    <div class="alert alert-danger jenkins-!-margin-top-1 jenkins-!-margin-bottom-0">
                       <pre>${p.cause.message}</pre>
                     </div>
                   </td>
diff --git a/core/src/main/resources/hudson/PluginManager/updates.jelly b/core/src/main/resources/hudson/PluginManager/updates.jelly
index 2b8cb9ad2850..25402731273b 100644
--- a/core/src/main/resources/hudson/PluginManager/updates.jelly
+++ b/core/src/main/resources/hudson/PluginManager/updates.jelly
@@ -136,7 +136,7 @@ THE SOFTWARE.
                           </div>
                         </j:if>
                         <j:if test="${!p.isCompatibleWithInstalledVersion()}">
-                          <div class="jenkins-alert jenkins-alert-danger">${%compatWarning}
+                          <div class="alert alert-danger">${%compatWarning}
                             <j:if test="${p.hasIncompatibleParentPlugins()}">
                               <br/>${%parentCompatWarning}
                               <ul>
@@ -153,15 +153,15 @@ THE SOFTWARE.
                           </div>
                         </j:if>
                         <j:if test="${p.isForNewerHudson()}">
-                          <div class="jenkins-alert jenkins-alert-danger">${%coreWarning(p.requiredCore)}</div>
+                          <div class="alert alert-danger">${%coreWarning(p.requiredCore)}</div>
                         </j:if>
                         <j:if test="${p.fixesSecurityVulnerabilities()}">
-                          <div class="jenkins-alert jenkins-alert-warning">
+                          <div class="alert alert-warning">
                             ${%Applying this update will address security vulnerabilities in the currently installed version.}
                           </div>
                         </j:if>
                         <j:if test="${!p.isNeededDependenciesCompatibleWithInstalledVersion(cache)}">
-                          <div class="jenkins-alert jenkins-alert-danger">${%depCompatWarning}
+                          <div class="alert alert-danger">${%depCompatWarning}
                             <br/>${%parentDepCompatWarning}
                             <ul>
                               <j:forEach var="d"
@@ -177,12 +177,12 @@ THE SOFTWARE.
                           </div>
                         </j:if>
                         <j:if test="${p.isNeededDependenciesForNewerJenkins(cache)}">
-                          <div class="jenkins-alert jenkins-alert-danger">
+                          <div class="alert alert-danger">
                             ${%depCoreWarning(p.getNeededDependenciesRequiredCore().toString())}
                           </div>
                         </j:if>
                         <j:if test="${p.hasWarnings()}">
-                          <div class="jenkins-alert jenkins-alert-danger">${%securityWarning}
+                          <div class="alert alert-danger">${%securityWarning}
                             <ul>
                               <j:forEach var="warning" items="${p.getWarnings()}">
                                 <li>
@@ -195,12 +195,12 @@ THE SOFTWARE.
                           </div>
                         </j:if>
                         <j:if test="${p.isDeprecated()}">
-                          <div class="jenkins-alert jenkins-alert-warning">
+                          <div class="alert alert-warning">
                             ${%deprecationWarning(p.getDeprecation().url)}
                           </div>
                         </j:if>
                         <j:if test="${it.hasAdoptThisPluginLabel(p)}">
-                          <div class="jenkins-alert jenkins-alert-warning">
+                          <div class="alert alert-warning">
                             ${%adoptThisPlugin}
                           </div>
                         </j:if>
diff --git a/core/src/main/resources/hudson/PluginWrapper/PluginWrapperAdministrativeMonitor/message.jelly b/core/src/main/resources/hudson/PluginWrapper/PluginWrapperAdministrativeMonitor/message.jelly
index 725457e4aa22..d7adbe4b57b6 100644
--- a/core/src/main/resources/hudson/PluginWrapper/PluginWrapperAdministrativeMonitor/message.jelly
+++ b/core/src/main/resources/hudson/PluginWrapper/PluginWrapperAdministrativeMonitor/message.jelly
@@ -1,6 +1,6 @@
 <?jelly escape-by-default='true'?>
 <j:jelly xmlns:j="jelly:core" xmlns:f="/lib/form">
-  <div class="jenkins-alert jenkins-alert-danger" role="alert">
+  <div class="alert alert-danger" role="alert">
     <form method="post" action="${rootURL}/${it.url}/act" name="${it.id}">
       <f:submit name="correct" value="${%Correct}"/>
     </form>
diff --git a/core/src/main/resources/hudson/diagnosis/HudsonHomeDiskUsageMonitor/message.jelly b/core/src/main/resources/hudson/diagnosis/HudsonHomeDiskUsageMonitor/message.jelly
index 488407988acf..1ff3673ab660 100644
--- a/core/src/main/resources/hudson/diagnosis/HudsonHomeDiskUsageMonitor/message.jelly
+++ b/core/src/main/resources/hudson/diagnosis/HudsonHomeDiskUsageMonitor/message.jelly
@@ -24,7 +24,7 @@ THE SOFTWARE.
 
 <?jelly escape-by-default='true'?>
 <j:jelly xmlns:j="jelly:core" xmlns:st="jelly:stapler" xmlns:d="jelly:define" xmlns:l="/lib/layout" xmlns:t="/lib/hudson" xmlns:f="/lib/form">
-<div class="jenkins-alert jenkins-alert-warning">
+<div class="alert alert-warning">
   <form method="post" action="${rootURL}/${it.url}/act" name="${it.id}">
     <f:submit name="yes" value="${%Tell me more}"/>
     <f:submit name="no" value="${%Dismiss}"/>
diff --git a/core/src/main/resources/hudson/diagnosis/NullIdDescriptorMonitor/message.jelly b/core/src/main/resources/hudson/diagnosis/NullIdDescriptorMonitor/message.jelly
index 06aee82322cb..610d36a6be8b 100644
--- a/core/src/main/resources/hudson/diagnosis/NullIdDescriptorMonitor/message.jelly
+++ b/core/src/main/resources/hudson/diagnosis/NullIdDescriptorMonitor/message.jelly
@@ -24,7 +24,7 @@ THE SOFTWARE.
 
 <?jelly escape-by-default='true'?>
 <j:jelly xmlns:j="jelly:core" xmlns:st="jelly:stapler" xmlns:d="jelly:define" xmlns:l="/lib/layout" xmlns:t="/lib/hudson" xmlns:f="/lib/form">
-<div class="jenkins-alert jenkins-alert-danger">
+<div class="alert alert-danger">
   <dl>
     <dt>${%blurb}</dt>
     <j:forEach var="d" items="${it.problems}">
diff --git a/core/src/main/resources/hudson/diagnosis/OldDataMonitor/message.jelly b/core/src/main/resources/hudson/diagnosis/OldDataMonitor/message.jelly
index c6d274d99031..c213f7ac2251 100644
--- a/core/src/main/resources/hudson/diagnosis/OldDataMonitor/message.jelly
+++ b/core/src/main/resources/hudson/diagnosis/OldDataMonitor/message.jelly
@@ -24,7 +24,7 @@ THE SOFTWARE.
 
 <?jelly escape-by-default='true'?>
 <j:jelly xmlns:j="jelly:core" xmlns:st="jelly:stapler" xmlns:d="jelly:define" xmlns:l="/lib/layout" xmlns:t="/lib/hudson" xmlns:f="/lib/form">
-  <div class="jenkins-alert jenkins-alert-warning">
+  <div class="alert alert-warning">
     <form method="post" action="${rootURL}/${it.url}/act" name="${it.id}">
       <f:submit name="yes" value="${%Manage}"/>
       <f:submit name="no" value="${%Dismiss}"/>
diff --git a/core/src/main/resources/hudson/diagnosis/ReverseProxySetupMonitor/message.jelly b/core/src/main/resources/hudson/diagnosis/ReverseProxySetupMonitor/message.jelly
index c7367563a257..c86699d26751 100644
--- a/core/src/main/resources/hudson/diagnosis/ReverseProxySetupMonitor/message.jelly
+++ b/core/src/main/resources/hudson/diagnosis/ReverseProxySetupMonitor/message.jelly
@@ -23,7 +23,7 @@ THE SOFTWARE.
 -->
 <?jelly escape-by-default='true'?>
 <j:jelly xmlns:j="jelly:core" xmlns:st="jelly:stapler" xmlns:f="/lib/form" xmlns:l="/lib/layout">
-  <div id="redirect-error" class="jenkins-alert jenkins-alert-danger reverse-proxy__hidden"
+  <div id="redirect-error" class="alert alert-danger reverse-proxy__hidden"
        data-url="${rootURL}/${it.url}/test" data-context="${rootURL}">
     <form method="post" action="${rootURL}/${it.url}/act" name="${it.id}">
       <f:submit name="yes" value="${%More Info}"/>
diff --git a/core/src/main/resources/hudson/diagnosis/TooManyJobsButNoView/message.jelly b/core/src/main/resources/hudson/diagnosis/TooManyJobsButNoView/message.jelly
index 178bbebeddb6..7c93986f6b95 100644
--- a/core/src/main/resources/hudson/diagnosis/TooManyJobsButNoView/message.jelly
+++ b/core/src/main/resources/hudson/diagnosis/TooManyJobsButNoView/message.jelly
@@ -24,7 +24,7 @@ THE SOFTWARE.
 
 <?jelly escape-by-default='true'?>
 <j:jelly xmlns:j="jelly:core" xmlns:st="jelly:stapler" xmlns:d="jelly:define" xmlns:l="/lib/layout" xmlns:t="/lib/hudson" xmlns:f="/lib/form">
-  <div id="tooManyJobsButNoView" class="jenkins-alert jenkins-alert-warning">
+  <div id="tooManyJobsButNoView" class="alert alert-warning">
     <l:isAdmin>
       <form method="post" action="${rootURL}/${it.url}/act" name="${it.id}">
         <f:submit name="yes" value="${%Create a view now}"/>
diff --git a/core/src/main/resources/hudson/logging/LogRecorder/configure.jelly b/core/src/main/resources/hudson/logging/LogRecorder/configure.jelly
index b49ccc278858..aba5588ccd13 100644
--- a/core/src/main/resources/hudson/logging/LogRecorder/configure.jelly
+++ b/core/src/main/resources/hudson/logging/LogRecorder/configure.jelly
@@ -36,7 +36,7 @@ THE SOFTWARE.
     </l:app-bar>
 
     <f:form method="post" name="config" action="configSubmit">
-      <div class="jenkins-alert jenkins-alert-info jenkins-form-item">
+      <div class="alert alert-info jenkins-form-item">
         ${%fine_warning}
       </div>
       <j:set var="instance" value="${it}" />
diff --git a/core/src/main/resources/hudson/logging/LogRecorderManager/all.jelly b/core/src/main/resources/hudson/logging/LogRecorderManager/all.jelly
index d14eeb77b675..71779ed1f4e7 100644
--- a/core/src/main/resources/hudson/logging/LogRecorderManager/all.jelly
+++ b/core/src/main/resources/hudson/logging/LogRecorderManager/all.jelly
@@ -36,7 +36,7 @@ THE SOFTWARE.
       </l:overflowButton>
     </l:app-bar>
 
-    <div class="jenkins-alert jenkins-alert-info">
+    <div class="alert alert-info">
       Log messages at a level more verbose than INFO (i.e., CONFIG, FINE, FINER, FINEST) are never recorded in the Jenkins log. Use <a href=".">log recorders</a> to record these log messages.
     </div>
     <t:logRecords logRecords="${h.logRecords}"/>
diff --git a/core/src/main/resources/hudson/model/UpdateCenter/CoreUpdateMonitor/message.jelly b/core/src/main/resources/hudson/model/UpdateCenter/CoreUpdateMonitor/message.jelly
index f11ee8837cdd..8419f13ce05c 100644
--- a/core/src/main/resources/hudson/model/UpdateCenter/CoreUpdateMonitor/message.jelly
+++ b/core/src/main/resources/hudson/model/UpdateCenter/CoreUpdateMonitor/message.jelly
@@ -24,7 +24,7 @@ THE SOFTWARE.
 
 <?jelly escape-by-default='true'?>
 <j:jelly xmlns:j="jelly:core" xmlns:st="jelly:stapler" xmlns:d="jelly:define" xmlns:l="/lib/layout" xmlns:t="/lib/hudson" xmlns:f="/lib/form">
-  <div class="jenkins-alert jenkins-alert-info">
+  <div class="alert alert-info">
     <j:set var="ucData" value="${it.data}" />
     <j:set var="upJob" value="${app.updateCenter.hudsonJob}" />
     <j:choose>
diff --git a/core/src/main/resources/hudson/node_monitors/MonitorMarkedNodeOffline/message.jelly b/core/src/main/resources/hudson/node_monitors/MonitorMarkedNodeOffline/message.jelly
index 52a2bd1df659..dda68d1ea6d2 100644
--- a/core/src/main/resources/hudson/node_monitors/MonitorMarkedNodeOffline/message.jelly
+++ b/core/src/main/resources/hudson/node_monitors/MonitorMarkedNodeOffline/message.jelly
@@ -24,7 +24,7 @@ THE SOFTWARE.
 
 <?jelly escape-by-default='true'?>
 <j:jelly xmlns:j="jelly:core" xmlns:st="jelly:stapler" xmlns:d="jelly:define" xmlns:l="/lib/layout" xmlns:t="/lib/hudson" xmlns:f="/lib/form">
-  <div class="jenkins-alert jenkins-alert-warning">
+  <div class="alert alert-warning">
     <form method="post" action="${rootURL}/${it.url}/disable">
       <f:submit value="${%Dismiss}"/>
     </form>
diff --git a/core/src/main/resources/hudson/triggers/SCMTrigger/AdministrativeMonitorImpl/message.jelly b/core/src/main/resources/hudson/triggers/SCMTrigger/AdministrativeMonitorImpl/message.jelly
index 47cadeea4f34..353b1fbc28f7 100644
--- a/core/src/main/resources/hudson/triggers/SCMTrigger/AdministrativeMonitorImpl/message.jelly
+++ b/core/src/main/resources/hudson/triggers/SCMTrigger/AdministrativeMonitorImpl/message.jelly
@@ -24,7 +24,7 @@ THE SOFTWARE.
 
 <?jelly escape-by-default='true'?>
 <j:jelly xmlns:j="jelly:core" xmlns:st="jelly:stapler" xmlns:d="jelly:define" xmlns:t="/lib/hudson">
-  <div class="jenkins-alert jenkins-alert-warning">
+  <div class="alert alert-warning">
     ${%blurb(rootURL)}
   </div>
 </j:jelly>
diff --git a/core/src/main/resources/hudson/triggers/SlowTriggerAdminMonitor/message.groovy b/core/src/main/resources/hudson/triggers/SlowTriggerAdminMonitor/message.groovy
index cef8cd83fae9..77bcedd36ebd 100644
--- a/core/src/main/resources/hudson/triggers/SlowTriggerAdminMonitor/message.groovy
+++ b/core/src/main/resources/hudson/triggers/SlowTriggerAdminMonitor/message.groovy
@@ -8,7 +8,7 @@ import org.apache.commons.jelly.tags.fmt.FmtTagLibrary
 SlowTriggerAdminMonitor tam = my
 
 dl {
-    div(class: "jenkins-alert jenkins-alert-warning") {
+    div(class: "alert alert-warning") {
         form(method: "post", name: "clear", action: rootURL + "/" + tam.url + "/clear") {
             input(name: "clear", type: "submit", value: _("Dismiss"), class: "submit-button primary")
         }
diff --git a/core/src/main/resources/hudson/util/AdministrativeError/message.jelly b/core/src/main/resources/hudson/util/AdministrativeError/message.jelly
index 3dfd16729c28..7da753ae759a 100644
--- a/core/src/main/resources/hudson/util/AdministrativeError/message.jelly
+++ b/core/src/main/resources/hudson/util/AdministrativeError/message.jelly
@@ -24,7 +24,7 @@ THE SOFTWARE.
 
 <?jelly escape-by-default='true'?>
 <j:jelly xmlns:j="jelly:core" xmlns:st="jelly:stapler" xmlns:d="jelly:define" xmlns:l="/lib/layout" xmlns:t="/lib/hudson" xmlns:f="/lib/form">
-  <div class="jenkins-alert jenkins-alert-danger">
+  <div class="alert alert-danger">
     <j:out value="${it.message}"/>
     <a href="${rootURL}/${it.url}/">${%See the log for more details}</a>.
   </div>
diff --git a/core/src/main/resources/hudson/util/DoubleLaunchChecker/message.jelly b/core/src/main/resources/hudson/util/DoubleLaunchChecker/message.jelly
index 865906efd3ea..9f7354230dbc 100644
--- a/core/src/main/resources/hudson/util/DoubleLaunchChecker/message.jelly
+++ b/core/src/main/resources/hudson/util/DoubleLaunchChecker/message.jelly
@@ -24,7 +24,7 @@ THE SOFTWARE.
 
 <?jelly escape-by-default='true'?>
 <j:jelly xmlns:j="jelly:core" xmlns:st="jelly:stapler" xmlns:d="jelly:define" xmlns:l="/lib/layout" xmlns:t="/lib/hudson" xmlns:f="/lib/form" xmlns:i="jelly:fmt">
-  <div class="jenkins-alert jenkins-alert-warning">
+  <div class="alert alert-warning">
       <p>
         ${%message(it.home)}
       </p>
diff --git a/core/src/main/resources/jenkins/diagnosis/HsErrPidList/message.jelly b/core/src/main/resources/jenkins/diagnosis/HsErrPidList/message.jelly
index dbd012f51c87..110d48ba7752 100644
--- a/core/src/main/resources/jenkins/diagnosis/HsErrPidList/message.jelly
+++ b/core/src/main/resources/jenkins/diagnosis/HsErrPidList/message.jelly
@@ -24,7 +24,7 @@ THE SOFTWARE.
 
 <?jelly escape-by-default='true'?>
 <j:jelly xmlns:j="jelly:core" xmlns:st="jelly:stapler" xmlns:d="jelly:define" xmlns:l="/lib/layout" xmlns:t="/lib/hudson" xmlns:f="/lib/form">
-  <div class="jenkins-alert jenkins-alert-danger">
+  <div class="alert alert-danger">
     ${%blurb(rootURL+'/'+it.url)}
   </div>
 </j:jelly>
\ No newline at end of file
diff --git a/core/src/main/resources/jenkins/diagnostics/CompletedInitializationMonitor/message.jelly b/core/src/main/resources/jenkins/diagnostics/CompletedInitializationMonitor/message.jelly
index 657efb6c2454..bf56e41455a4 100644
--- a/core/src/main/resources/jenkins/diagnostics/CompletedInitializationMonitor/message.jelly
+++ b/core/src/main/resources/jenkins/diagnostics/CompletedInitializationMonitor/message.jelly
@@ -1,6 +1,6 @@
 <?jelly escape-by-default='true'?>
 <j:jelly xmlns:j="jelly:core" xmlns:st="jelly:stapler" xmlns:d="jelly:define" xmlns:l="/lib/layout" xmlns:t="/lib/hudson" xmlns:f="/lib/form">
-  <div class="jenkins-alert jenkins-alert-warning">
+  <div class="alert alert-warning">
       ${%blurb(app.initLevel)}
       ${%Example: usage of} <code>@Initializer(after = InitMilestone.COMPLETED)</code> ${%in a plugin}
       (<a href="https://www.jenkins.io/redirect/troubleshooting/initialization-not-completed" rel="noopener noreferrer" target="_blank">${%See documentation}</a>).
diff --git a/core/src/main/resources/jenkins/diagnostics/ControllerExecutorsAgents/message.jelly b/core/src/main/resources/jenkins/diagnostics/ControllerExecutorsAgents/message.jelly
index 5cbd262425a3..6824021fe83d 100644
--- a/core/src/main/resources/jenkins/diagnostics/ControllerExecutorsAgents/message.jelly
+++ b/core/src/main/resources/jenkins/diagnostics/ControllerExecutorsAgents/message.jelly
@@ -24,7 +24,7 @@ THE SOFTWARE.
 
 <?jelly escape-by-default='true'?>
 <j:jelly xmlns:j="jelly:core" xmlns:st="jelly:stapler" xmlns:d="jelly:define" xmlns:l="/lib/layout" xmlns:t="/lib/hudson" xmlns:f="/lib/form">
-  <div class="jenkins-alert jenkins-alert-warning">
+  <div class="alert alert-warning">
      <form method="post" action="${rootURL}/${it.url}/act" name="${it.id}">
       <f:submit name="yes" value="${%Manage}"/>
       <f:submit name="no" value="${%Dismiss}"/>
diff --git a/core/src/main/resources/jenkins/diagnostics/ControllerExecutorsNoAgents/message.jelly b/core/src/main/resources/jenkins/diagnostics/ControllerExecutorsNoAgents/message.jelly
index 1f8f0fb8bd8c..41c6487d5263 100644
--- a/core/src/main/resources/jenkins/diagnostics/ControllerExecutorsNoAgents/message.jelly
+++ b/core/src/main/resources/jenkins/diagnostics/ControllerExecutorsNoAgents/message.jelly
@@ -24,7 +24,7 @@ THE SOFTWARE.
 
 <?jelly escape-by-default='true'?>
 <j:jelly xmlns:j="jelly:core" xmlns:st="jelly:stapler" xmlns:d="jelly:define" xmlns:l="/lib/layout" xmlns:t="/lib/hudson" xmlns:f="/lib/form">
-  <div class="jenkins-alert jenkins-alert-warning">
+  <div class="alert alert-warning">
     <form method="post" action="${rootURL}/${it.url}/act" name="${it.id}">
       <f:submit name="agent" value="${%Set up agent}"/>
       <f:submit name="cloud" value="${%Set up cloud}"/>
diff --git a/core/src/main/resources/jenkins/diagnostics/RootUrlNotSetMonitor/message.jelly b/core/src/main/resources/jenkins/diagnostics/RootUrlNotSetMonitor/message.jelly
index 94a5b777b58c..dcd5b742511d 100644
--- a/core/src/main/resources/jenkins/diagnostics/RootUrlNotSetMonitor/message.jelly
+++ b/core/src/main/resources/jenkins/diagnostics/RootUrlNotSetMonitor/message.jelly
@@ -23,7 +23,7 @@ THE SOFTWARE.
 -->
 <?jelly escape-by-default='true'?>
 <j:jelly xmlns:j="jelly:core" xmlns:f="/lib/form" xmlns:l="/lib/layout">
-  <div class="jenkins-alert jenkins-alert-warning">
+  <div class="alert alert-warning">
     <l:isAdmin>
       <form method="post" action="${rootURL}/${it.url}/disable">
         <f:submit value="${%Dismiss}"/>
diff --git a/core/src/main/resources/jenkins/diagnostics/SecurityIsOffMonitor/message.jelly b/core/src/main/resources/jenkins/diagnostics/SecurityIsOffMonitor/message.jelly
index 65895c8c79c4..1b08c2698a89 100644
--- a/core/src/main/resources/jenkins/diagnostics/SecurityIsOffMonitor/message.jelly
+++ b/core/src/main/resources/jenkins/diagnostics/SecurityIsOffMonitor/message.jelly
@@ -24,7 +24,7 @@ THE SOFTWARE.
 
 <?jelly escape-by-default='true'?>
 <j:jelly xmlns:j="jelly:core" xmlns:st="jelly:stapler" xmlns:d="jelly:define" xmlns:l="/lib/layout" xmlns:t="/lib/hudson" xmlns:f="/lib/form">
-  <div class="jenkins-alert jenkins-alert-warning">
+  <div class="alert alert-warning">
     <form method="post" action="${rootURL}/${it.url}/act" name="${it.id}">
       <f:submit name="yes" value="${%Setup Security}"/>
       <f:submit name="no" value="${%Dismiss}"/>
diff --git a/core/src/main/resources/jenkins/install/SetupWizard/authenticate-security-token.jelly b/core/src/main/resources/jenkins/install/SetupWizard/authenticate-security-token.jelly
index 2adc245beb0f..8c290f10261c 100644
--- a/core/src/main/resources/jenkins/install/SetupWizard/authenticate-security-token.jelly
+++ b/core/src/main/resources/jenkins/install/SetupWizard/authenticate-security-token.jelly
@@ -19,7 +19,7 @@
                     <p>${%jenkins.install.findSecurityTokenMessage(it.initialAdminPasswordFile)}</p>
                     <p>${%authenticate-security-token.copy.password}</p>
                     <j:if test="${error}">
-                        <div class="jenkins-alert jenkins-alert-danger">
+                        <div class="alert alert-danger">
                           <strong>${%authenticate-security-token.error}</strong> ${%authenticate-security-token.password.incorrect}
                         </div>
                     </j:if>
diff --git a/core/src/main/resources/jenkins/install/pluginSetupWizard.properties b/core/src/main/resources/jenkins/install/pluginSetupWizard.properties
index 6c74f8b2ab40..86fd3f21517f 100644
--- a/core/src/main/resources/jenkins/install/pluginSetupWizard.properties
+++ b/core/src/main/resources/jenkins/install/pluginSetupWizard.properties
@@ -66,7 +66,7 @@ installWizard_installIncomplete_message=Jenkins was restarted during installatio
 installWizard_installIncomplete_resumeInstallationButtonLabel=Resume
 installWizard_saveFirstUser=Save and Continue
 installWizard_skipFirstUser=Skip and continue as admin
-installWizard_firstUserSkippedMessage=<div class="jenkins-alert jenkins-alert-warning fade in">\
+installWizard_firstUserSkippedMessage=<div class="alert alert-warning fade in">\
 You have skipped the <strong>setup of an admin user</strong>. <br /><br />\
 To log in, use the username: "admin" and the administrator password you used to access the setup wizard.\
 </div>
@@ -76,7 +76,7 @@ installWizard_addFirstUser_title=Getting Started
 installWizard_configureInstance_title=Instance Configuration
 installWizard_saveConfigureInstance=Save and Finish
 installWizard_skipConfigureInstance=Not now
-installWizard_configureInstanceSkippedMessage=<div class="jenkins-alert jenkins-alert-warning fade in">\
+installWizard_configureInstanceSkippedMessage=<div class="alert alert-warning fade in">\
 You have skipped the configuration of the Jenkins URL. <br/><br/>\
 To configure the Jenkins URL, go to "Manage Jenkins" page.\
 </div>
@@ -103,7 +103,7 @@ installWizard_pluginsInstalled_banner=Welcome to Jenkins {0}!
 installWizard_upgradeComplete_message=Congratulations! You have upgraded to Jenkins {0}.</p><p>To learn more about its great new features, visit <a rel="noopener noreferrer" target="_blank" href="https://www.jenkins.io/2.0/">the Jenkins website</a>!
 installWizard_upgradeSkipped_title=Upgrade
 installWizard_upgradeSkipped_banner=Features Not Installed
-installWizard_upgradeSkipped_message=<div class="jenkins-alert jenkins-alert-warning fade in">Suggested plugins will not be installed.</div> \
+installWizard_upgradeSkipped_message=<div class="alert alert-warning fade in">Suggested plugins will not be installed.</div> \
 <p style="padding: 0 4px">You can also install new features from the Plugin Manager, if you change your mind.</p> \
 <p style="padding: 0 4px">Learn how these new features can improve your Jenkins experience by \
 <a rel="noopener noreferrer" target="_blank" href="https://www.jenkins.io/2.0/">visiting the homepage</a>.</p>
diff --git a/core/src/main/resources/jenkins/install/pluginSetupWizard_fr.properties b/core/src/main/resources/jenkins/install/pluginSetupWizard_fr.properties
index a20036a079bf..df38499238db 100644
--- a/core/src/main/resources/jenkins/install/pluginSetupWizard_fr.properties
+++ b/core/src/main/resources/jenkins/install/pluginSetupWizard_fr.properties
@@ -41,7 +41,7 @@ certains plugins n\'ont pas l\'air d\'avoir été installés.
 installWizard_installIncomplete_resumeInstallationButtonLabel=Reprendre
 installWizard_saveFirstUser=Sauver et continuer
 installWizard_skipFirstUser=Continuer en tant qu\'Administrateur
-installWizard_firstUserSkippedMessage=<div class="jenkins-alert jenkins-alert-warning fade in">\
+installWizard_firstUserSkippedMessage=<div class="alert alert-warning fade in">\
 Vous avez passé la <strong>création d\'un utilisateur administrateur</strong>. <br /><br />\
 Pour vous connecter, utilisez le login : "admin" et le mot de passe administrateur que vous avez utilisé pour accéder au \
 wizard d\'installation.</div>
@@ -49,7 +49,7 @@ installWizard_addFirstUser_title=Démarrage
 
 # instance configuration page
 installWizard_configureInstance_title=Démarrage
-installWizard_configureInstanceSkippedMessage=<div class="jenkins-alert jenkins-alert-warning fade in">\
+installWizard_configureInstanceSkippedMessage=<div class="alert alert-warning fade in">\
 Vous avez passé la <strong>configuration de l\'instance</strong>. <br /><br /> \
 Vous pouvez toujours vous rendre sur les pages de configuration pour remplir les informations qui pourraient manquer.\
 </div>
diff --git a/core/src/main/resources/jenkins/install/pluginSetupWizard_it.properties b/core/src/main/resources/jenkins/install/pluginSetupWizard_it.properties
index dcf21537815f..395e4aa864e0 100644
--- a/core/src/main/resources/jenkins/install/pluginSetupWizard_it.properties
+++ b/core/src/main/resources/jenkins/install/pluginSetupWizard_it.properties
@@ -23,7 +23,7 @@
 
 installWizard_addFirstUser_title=Attività iniziali
 installWizard_configureInstanceSkippedMessage=\
-  <div class="jenkins-alert jenkins-alert-warning fade in">La configurazione dell''URL di \
+  <div class="alert alert-warning fade in">La configurazione dell''URL di \
   Jenkins è stata omessa.<br/><br/>Per configurare l''URL di Jenkins, aprire \
   la pagina "Gestisci Jenkins".</div>
 installWizard_configureInstance_title=Configurazione istanza
@@ -37,7 +37,7 @@ installWizard_error_restartNotSupported=Il riavvio non è supportato, \
   riavviare quest''istanza manualmente
 installWizard_error_title=Errore
 installWizard_firstUserSkippedMessage=\
-  <div class="jenkins-alert jenkins-alert-warning fade in">La <strong>configurazione di un \
+  <div class="alert alert-warning fade in">La <strong>configurazione di un \
   utente amministratore</strong> è stata omessa.<br /><br />Per accedere, \
   utilizzare il nome utente "admin" e la password di amministrazione che si \
   è utilizzata per accedere alla configurazione guidata.</div>
@@ -113,7 +113,7 @@ installWizard_upgradePanel_message=Jenkins {0} include delle nuove \
 installWizard_upgradePanel_skipRecommendedPlugins=No, grazie
 installWizard_upgradePanel_title=Aggiornamento
 installWizard_upgradeSkipped_banner=Funzionalità non installate
-installWizard_upgradeSkipped_message=<div class="jenkins-alert jenkins-alert-warning fade \
+installWizard_upgradeSkipped_message=<div class="alert alert-warning fade \
   in">I componenti aggiuntivi consigliati non saranno installati.</div>\
   <p style="padding: 0 4px">È possibile anche installare nuove funzionalità \
   dal Gestore componenti aggiuntivi se si cambia idea.</p><p style="padding: \
diff --git a/core/src/main/resources/jenkins/install/pluginSetupWizard_lt.properties b/core/src/main/resources/jenkins/install/pluginSetupWizard_lt.properties
index 91d7f50475a4..97f1ae20bc42 100644
--- a/core/src/main/resources/jenkins/install/pluginSetupWizard_lt.properties
+++ b/core/src/main/resources/jenkins/install/pluginSetupWizard_lt.properties
@@ -39,7 +39,7 @@ installWizard_installIncomplete_message=Jenkinsas buvo iš naujo paleistas diegi
 installWizard_installIncomplete_resumeInstallationButtonLabel=Tęsti
 installWizard_saveFirstUser=Įrašyti ir baigti
 installWizard_skipFirstUser=Tęsti kaip administratoriumi
-installWizard_firstUserSkippedMessage=<div class="jenkins-alert jenkins-alert-warning fade in">\
+installWizard_firstUserSkippedMessage=<div class="alert alert-warning fade in">\
 Jūs praleidote administratoriaus naudotojo kūrimą. Norėdami prisijungti, naudokite vardą: „admin“ ir \
 administratoriaus slaptažodį, kurį naudojote prisijungimui prie nustatymo vedlio.\
 </div>
diff --git a/core/src/main/resources/jenkins/install/pluginSetupWizard_pl.properties b/core/src/main/resources/jenkins/install/pluginSetupWizard_pl.properties
index 674374d36c72..9ded00d8ffce 100644
--- a/core/src/main/resources/jenkins/install/pluginSetupWizard_pl.properties
+++ b/core/src/main/resources/jenkins/install/pluginSetupWizard_pl.properties
@@ -31,7 +31,7 @@ installWizard_jenkinsVersionTitle=Jenkins
 installWizard_installComplete_banner=Jenkins jest gotowy!
 installWizard_installComplete_finishButtonLabel=Zacznij korzystać z Jenkinsa
 installWizard_installComplete_message=Konfiguracja Jenkinsa została zakończona.
-installWizard_firstUserSkippedMessage=<div class="jenkins-alert jenkins-alert-warning fade in">\
+installWizard_firstUserSkippedMessage=<div class="alert alert-warning fade in">\
 Pominięto utworzenie konta administratora. Aby się zalogować, użyj loginu 'admin' i hasła użytego podczas konfigurowania Jenkinsa.\
 </div>
 installWizard_addFirstUser_title=Dodawanie pierwszego użytkownika
@@ -79,7 +79,7 @@ installWizard_installComplete_installComplete_restartRequiredNotSupportedMessage
 installWizard_gettingStarted_title=Zaczynamy
 installWizard_saveSecurity=Zapisz i kontynuuj
 installWizard_installIncomplete_dependenciesLabel=Zależności
-installWizard_configureInstanceSkippedMessage=<div class="jenkins-alert jenkins-alert-warning fade in">\
+installWizard_configureInstanceSkippedMessage=<div class="alert alert-warning fade in">\
 Pominięto konfiguracje bazowego adresu URL Jenkinsa. <br/><br/>\
 Aby go skonfigurować, przejdź do strony "Zarządzaj Jenkinsem".\
 </div>
diff --git a/core/src/main/resources/jenkins/install/pluginSetupWizard_pt_BR.properties b/core/src/main/resources/jenkins/install/pluginSetupWizard_pt_BR.properties
index f633aa0e1ab0..31fee518e999 100644
--- a/core/src/main/resources/jenkins/install/pluginSetupWizard_pt_BR.properties
+++ b/core/src/main/resources/jenkins/install/pluginSetupWizard_pt_BR.properties
@@ -38,7 +38,7 @@ installWizard_error_connection=Incapaz de conectar ao Jenkins
 installWizard_installing_detailsLink=Detalhes...
 installWizard_gettingStarted_title=Começando
 installWizard_installIncomplete_title=Prosseguir com a instalação
-installWizard_configureInstanceSkippedMessage=<div class="jenkins-alert jenkins-alert-warning fade in">Você pulou a configuração da \
+installWizard_configureInstanceSkippedMessage=<div class="alert alert-warning fade in">Você pulou a configuração da \
   URL do Jenkins. <br/><br/>Para configurá-la, vá para a página "Gerenciar o Jenkins".</div>
 installWizard_installIncomplete_banner=Prosseguir com a instalação
 installWizard_welcomePanel_recommendedActionTitle=Instalar as extensões sugeridas
@@ -52,7 +52,7 @@ installWizard_installComplete_installComplete_restartRequiredMessage=A configura
 installWizard_installComplete_bannerRestart=O Jenkins está quase pronto!
 installWizard_skipFirstUser=Pular e continuar como administrador
 installWizard_installCustom_dependenciesPrefix=Dependências
-installWizard_upgradeSkipped_message=<div class="jenkins-alert jenkins-alert-warning fade in">As extensões sugeridas não serão \
+installWizard_upgradeSkipped_message=<div class="alert alert-warning fade in">As extensões sugeridas não serão \
   instaladas.</div> <p style="padding: 0 4px">Você pode instalar extensões com o Gerenciador de Extensões, caso mude \
   de ideia.</p> <p style="padding: 0 4px">Aprenda como estas novas funcionalidades podem melhorar sua experiência com \
   o Jenkins <a rel="noopener noreferrer" target="_blank" href="https://www.jenkins.io/2.0/">visitando sua página \
@@ -82,7 +82,7 @@ installWizard_installComplete_finishButtonLabel=Começar a usar o Jenkins
 installWizard_goInstall=Instalar
 installWizard_installCustom_selectNone=Nenhum
 installWizard_installComplete_title=Começar
-installWizard_firstUserSkippedMessage=<div class="jenkins-alert jenkins-alert-warning fade in">Você pulou a <strong>configuração do \
+installWizard_firstUserSkippedMessage=<div class="alert alert-warning fade in">Você pulou a <strong>configuração do \
   usuário admin</strong>. <br /><br />Para entrar, use o nome de usuário "admin" e a senha de administrador que você \
   usou para acessar o assistente de configuração.</div>
 installWizard_configureProxy_save=Salvar e continuar
diff --git a/core/src/main/resources/jenkins/install/pluginSetupWizard_sr.properties b/core/src/main/resources/jenkins/install/pluginSetupWizard_sr.properties
index 16c3931e91aa..14a3affb5905 100644
--- a/core/src/main/resources/jenkins/install/pluginSetupWizard_sr.properties
+++ b/core/src/main/resources/jenkins/install/pluginSetupWizard_sr.properties
@@ -40,7 +40,7 @@ installWizard_installIncomplete_banner=Настави са инсталациј
 installWizard_installIncomplete_message=
 installWizard_saveFirstUser=Сачувај и настави
 installWizard_skipFirstUser=Настави са администраторским налогом
-installWizard_firstUserSkippedMessage=<div class="jenkins-alert jenkins-alert-warning fade in">\
+installWizard_firstUserSkippedMessage=<div class="alert alert-warning fade in">\
 Прескочили сте креирањем административог корисника. Пријавите се како што ће те користити име: 'admin' и лозинку коју сте користили инсталацијом.\
 </div>
 installWizard_addFirstUser_title=Почетак
@@ -65,7 +65,7 @@ installWizard_pluginsInstalled_banner=Добродошли на Jenkins {0}!
 installWizard_upgradeComplete_message=Честитамо! Ажурирали сте Jenkins на верзију {0}.</p><p>Прочитајте још на <a rel="noopener noreferrer" target="_blank" href="https://www.jenkins.io/2.0/">Jenkins страници</a>!
 installWizard_upgradeSkipped_title=Ажурирај
 installWizard_upgradeSkipped_banner=Одлике које нису инсталиране
-installWizard_upgradeSkipped_message=<div class="jenkins-alert jenkins-alert-warning fade in">предложие модуле неће бити инсталиране.</div> \
+installWizard_upgradeSkipped_message=<div class="alert alert-warning fade in">предложие модуле неће бити инсталиране.</div> \
 <p style="padding: 0 4px">Ако сте предомислите, можете инсталирати нове модуле са Управљачем модула.</p> \
 <p style="padding: 0 4px">Прочитајте како модуле усавршавају Jenkins \
 <a rel="noopener noreferrer" target="_blank" href="https://www.jenkins.io/2.0/">на Jenkins станици</a>.</p>
diff --git a/core/src/main/resources/jenkins/install/pluginSetupWizard_sv_SE.properties b/core/src/main/resources/jenkins/install/pluginSetupWizard_sv_SE.properties
deleted file mode 100644
index 8fc30a7b98c0..000000000000
--- a/core/src/main/resources/jenkins/install/pluginSetupWizard_sv_SE.properties
+++ /dev/null
@@ -1,111 +0,0 @@
-# The MIT License
-#
-# Copyright (c) 2016-2018, Sun Microsystems, Inc., Kohsuke Kawaguchi
-#
-# Permission is hereby granted, free of charge, to any person obtaining a copy
-# of this software and associated documentation files (the "Software"), to deal
-# in the Software without restriction, including without limitation the rights
-# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-# copies of the Software, and to permit persons to whom the Software is
-# furnished to do so, subject to the following conditions:
-#
-# The above copyright notice and this permission notice shall be included in
-# all copies or substantial portions of the Software.
-#
-# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-# THE SOFTWARE.
-#
-installWizard_welcomePanel_title=Kom igång
-installWizard_welcomePanel_banner=Anpassa Jenkins
-installWizard_welcomePanel_message=Insticksprogram utökar Jenkins med ytterligare funktioner för att stödja många olika behov.
-installWizard_welcomePanel_recommendedActionTitle=Installera föreslagna insticksprogram
-installWizard_welcomePanel_recommendedActionDetails=Installera de insticksprogram som Jenkins-gemenskapen finner mest användbara.
-installWizard_welcomePanel_customizeActionTitle=Välj insticksprogram att installera
-installWizard_welcomePanel_customizeActionDetails=Välj och installera insticksprogram som passar dina behov.
-installWizard_jenkinsVersionTitle=Jenkins 
-installWizard_offline_title=Frånkopplad
-installWizard_offline_message=Den här Jenkins-instansen verkar vara frånkopplad. \
-<p style="font-size:18px; margin-top: 6%"> \
-För information om att installera Jenkins utan internetanslutning, se \
-<a href="https://www.jenkins.io/redirect/offline-installation" rel="noopener noreferrer" target="_blank">dokumentationen om frånkopplad installation av Jenkins</a>. <br/><br/> \
-Du kan välja att fortsätta genom att konfigurera en proxy eller hoppa över installationen av insticksprogrammet. \
-</p>
-installWizard_error_title=Fel
-installWizard_error_header=Ett fel uppstod
-installWizard_error_message=Ett fel uppstod under installationen:
-installWizard_error_connection=Det går inte att ansluta till Jenkins
-installWizard_error_restartNotSupported=Omstart stöds inte. Starta om den här instansen manuellt
-installWizard_installCustom_title=Kom igång
-installWizard_installCustom_selectAll=Alla
-installWizard_installCustom_selectNone=Inga
-installWizard_installCustom_selectRecommended=Föreslagna
-installWizard_installCustom_selected=Markerade
-installWizard_installCustom_dependenciesPrefix=Beroenden
-installWizard_installCustom_pluginListDesc=Observera att hela listan över insticksprogram inte visas här. Ytterligare insticksprogram kan installeras i <strong>insticksprogramshanteraren</strong> när den första installationen är färdig. <a href="https://www.jenkins.io/redirect/installation-wizard" rel="noopener noreferrer" target="_blank">Mer information finns i dokumentationen</a>.
-installWizard_goBack=Tillbaka
-installWizard_goInstall=Installera
-installWizard_installing_title=Kom igång
-installWizard_installing_detailsLink=Detaljer...
-installWizard_installComplete_title=Kom igång
-installWizard_installComplete_banner=Jenkins är redo!
-installWizard_installComplete_bannerRestart=Jenkins är nästan redo!
-installWizard_pluginsInstalled_message=Installationen av dina insticksprogram är färdig.
-installWizard_installComplete_message=Din Jenkins-installation är färdig.
-installWizard_installComplete_finishButtonLabel=Börja använda Jenkins
-installWizard_installComplete_installComplete_restartRequiredMessage=Din Jenkins-installation är färdig, men vissa insticksprogram kräver att Jenkins startas om.
-installWizard_installComplete_installComplete_restartRequiredNotSupportedMessage=Din Jenkins-installation är färdig, men vissa insticksprogram kräver en omstart av Jenkins och det verkar som om denna instans saknar stöd för en automatisk omstart. Starta om din instans manuellt nu för att slutföra installationen.
-installWizard_installComplete_restartLabel=Starta om
-installWizard_installIncomplete_title=Återuppta installationen
-installWizard_installIncomplete_banner=Återuppta installationen
-installWizard_installIncomplete_message=Jenkins startades om under installationen och vissa insticksprogram verkade inte installeras.
-installWizard_installIncomplete_resumeInstallationButtonLabel=Återuppta
-installWizard_saveFirstUser=Spara och fortsätt
-installWizard_skipFirstUser=Hoppa över och fortsätt som administratör
-installWizard_firstUserSkippedMessage=<div class="jenkins-alert jenkins-alert-warning fade in">\
-Du har hoppat över <strong>installationen av en administratörsanvändare</strong>. <br /><br />\
-Använd användarnamnet "admin" och administratörslösenordet du använde för att komma åt installationsguiden för att logga in.\
-</div>
-installWizard_addFirstUser_title=Kom igång
-
-# instance configuration page
-installWizard_configureInstance_title=Konfigurera instans
-installWizard_saveConfigureInstance=Spara och avsluta
-installWizard_skipConfigureInstance=Inte nu
-installWizard_configureInstanceSkippedMessage=<div class="jenkins-alert jenkins-alert-warning fade in">\
-Du har hoppat över konfigurationen av Jenkins-webbadressen. <br/><br/>\
-Gå till sidan "Hantera Jenkins" för att konfigurera Jenkins-webbadressen.\
-</div>
-
-installWizard_configureProxy_label=Konfigurera proxy
-installWizard_configureProxy_save=Spara och fortsätt
-installWizard_gettingStarted_title=Kom igång
-installWizard_saveSecurity=Spara och fortsätt
-installWizard_skipPluginInstallations=Hoppa över installation av insticksprogram
-installWizard_installIncomplete_dependenciesLabel=Beroenden
-installWizard_installingConsole_dependencyIndicatorNote=** - nödvändigt beroende
-installWizard_websiteLinkLabel=Webbplats
-installWizard_pluginInstallFailure_title=Misslyckade installationer
-installWizard_pluginInstallFailure_message=Vissa insticksprogram kunde inte installeras korrekt. Du kan försöka installera dem igen eller \
- fortsätta utan alla misslyckade insticksprogram
-installWizard_continue=Fortsätt
-installWizard_retry=Försök igen
-installWizard_upgradePanel_title=Uppgradera
-installWizard_upgradePanel_banner=Välkommen till Jenkins {0}!
-installWizard_upgradePanel_message=Jenkins {0} innehåller några fantastiska nya funktioner som vi tror att du kommer att älska. Installera dessa ytterligare insticksprogram för att dra nytta av dem!
-installWizard_upgradePanel_skipRecommendedPlugins=Nej tack
-installWizard_upgradeComplete_title=Uppgradera
-installWizard_pluginsInstalled_banner=Välkommen till Jenkins {0}!
-installWizard_upgradeComplete_message=Grattis! Du har uppgraderat till Jenkins {0}.</p><p>Besök <a rel="noopener noreferrer" target="_blank" href="https://www.jenkins.io/2.0/">Jenkins webbplats</a> för att läsa mer om dessa fantastiska nya funktioner!
-installWizard_upgradeSkipped_title=Uppgradera
-installWizard_upgradeSkipped_banner=Oinstallerade funktioner
-installWizard_upgradeSkipped_message=<div class="jenkins-alert jenkins-alert-warning fade in">Föreslagna insticksprogram kommer inte att installeras.</div> \
-<p style="padding: 0 4px">Du kan också installera nya funktioner från insticksprogramshanteraren om du ångrar dig.</p> \
-<p style="padding: 0 4px">Läs om hur dessa nya funktioner kan förbättra din Jenkins-upplevelse genom att \
-<a rel="noopener noreferrer" target="_blank" href="https://www.jenkins.io/2.0/">besöka hemsidan</a>.</p>
-installWizard_upgrading_title=Installera insticksprogram
-installWizard_upgradeComplete_finishButtonLabel=Slutför
diff --git a/core/src/main/resources/jenkins/install/pluginSetupWizard_zh_CN.properties b/core/src/main/resources/jenkins/install/pluginSetupWizard_zh_CN.properties
index 3446a6b21cc4..526cf033bf9b 100644
--- a/core/src/main/resources/jenkins/install/pluginSetupWizard_zh_CN.properties
+++ b/core/src/main/resources/jenkins/install/pluginSetupWizard_zh_CN.properties
@@ -64,7 +64,7 @@ installWizard_installIncomplete_message=Jenkins在安装过程已重启，部分
 installWizard_installIncomplete_resumeInstallationButtonLabel=恢复
 installWizard_saveFirstUser=保存并完成
 installWizard_skipFirstUser=使用admin账户继续
-installWizard_firstUserSkippedMessage=<div class="jenkins-alert jenkins-alert-warning fade in">\
+installWizard_firstUserSkippedMessage=<div class="alert alert-warning fade in">\
 你已跳过创建admin用户的步骤。要登录请使用用户名：'admin' \
 及用于访问安装向导的管理员密码。\
 </div> 
@@ -74,7 +74,7 @@ installWizard_addFirstUser_title=新手入门
 installWizard_configureInstance_title=实例配置
 installWizard_saveConfigureInstance=保存并完成
 installWizard_skipConfigureInstance=现在不要
-installWizard_configureInstanceSkippedMessage=<div class="jenkins-alert jenkins-alert-warning fade in">\
+installWizard_configureInstanceSkippedMessage=<div class="alert alert-warning fade in">\
 您已经跳过了 Jenkins URL的配置。 <br/><br/>\
 要配置 Jenkins URL的话，到“Jenkins管理”页面。\
 </div>
@@ -100,7 +100,7 @@ installWizard_pluginsInstalled_banner=欢迎使用Jenkins {0} ！
 installWizard_upgradeComplete_message=恭喜！你已更新到Jenkins {0} 。</p><p>访问<a rel="noopener noreferrer" target="_blank" href="https://www.jenkins.io/2.0/">Jenkins网站</a>了解更多新特性的信息。
 installWizard_upgradeSkipped_title=更新
 installWizard_upgradeSkipped_banner=特性未安装
-installWizard_upgradeSkipped_message=<div class="jenkins-alert jenkins-alert-warning fade in">建议的插件将不被安装。</div> \
+installWizard_upgradeSkipped_message=<div class="alert alert-warning fade in">建议的插件将不被安装。</div> \
 <p style="padding: 0 4px">如果你改变主意了，还可以从插件管理器安装新特性。</p>\
 <p style="padding: 0 4px">访问<a rel="noopener noreferrer" target="_blank" href="https://www.jenkins.io/2.0/">Jenkins官网</a>，了解这些新特性如何提升Jenkins体验。</p>
 installWizard_upgrading_title=正在安装插件
diff --git a/core/src/main/resources/jenkins/install/pluginSetupWizard_zh_TW.properties b/core/src/main/resources/jenkins/install/pluginSetupWizard_zh_TW.properties
index 341d0ae88e70..8d42c1f95f86 100644
--- a/core/src/main/resources/jenkins/install/pluginSetupWizard_zh_TW.properties
+++ b/core/src/main/resources/jenkins/install/pluginSetupWizard_zh_TW.properties
@@ -61,14 +61,14 @@ installWizard_installIncomplete_message=Jenkins 在安裝期間重新啟動，
 installWizard_installIncomplete_resumeInstallationButtonLabel=繼續
 installWizard_saveFirstUser=儲存並繼續
 installWizard_skipFirstUser=跳過並以 admin 繼續
-installWizard_firstUserSkippedMessage=<div class\="jenkins-alert jenkins-alert-warning fade in">您已略過<strong>設定管理員使用者</strong>。<br /><br />請使用帳號：「admin」和您進入安裝精靈的管理員密碼登入。</div>
+installWizard_firstUserSkippedMessage=<div class\="alert alert-warning fade in">您已略過<strong>設定管理員使用者</strong>。<br /><br />請使用帳號：「admin」和您進入安裝精靈的管理員密碼登入。</div>
 installWizard_addFirstUser_title=開始使用
 
 # instance configuration page
 installWizard_configureInstance_title=執行個體組態
 installWizard_saveConfigureInstance=儲存並完成
 installWizard_skipConfigureInstance=暫時不要
-installWizard_configureInstanceSkippedMessage=<div class\="jenkins-alert jenkins-alert-warning fade in">您已略過設定 Jenkins URL。<br/><br/>您之後可以到「管理 Jenkins」頁面設定 Jenkins URL。</div>
+installWizard_configureInstanceSkippedMessage=<div class\="alert alert-warning fade in">您已略過設定 Jenkins URL。<br/><br/>您之後可以到「管理 Jenkins」頁面設定 Jenkins URL。</div>
 
 installWizard_configureProxy_label=設定代理伺服器
 installWizard_configureProxy_save=儲存並繼續
@@ -91,6 +91,6 @@ installWizard_pluginsInstalled_banner=歡迎使用 Jenkins {0}\!
 installWizard_upgradeComplete_message=恭喜！您已升級到 Jenkins {0}。</p><p>造訪 <a rel\="noopener noreferrer" target\="_blank" href\="https\://www.jenkins.io/2.0/">Jenkins 網站</a>以了解更多新功能的資訊！
 installWizard_upgradeSkipped_title=升级
 installWizard_upgradeSkipped_banner=功能未安裝
-installWizard_upgradeSkipped_message=<div class\="jenkins-alert jenkins-alert-warning fade in">不會安裝推薦的外掛。</div> <p style\="padding\: 0 4px">如果您改變主意了，您可從外掛總管安裝新功能。</p> <p style\="padding\: 0 4px">Learn how these new features can improve your Jenkins experience by <a rel\="noopener noreferrer" target\="_blank" href\="https\://www.jenkins.io/2.0/">造訪首頁</a>以了解這些新功能如何提升您的 Jenkins 使用體驗。</p>
+installWizard_upgradeSkipped_message=<div class\="alert alert-warning fade in">不會安裝推薦的外掛。</div> <p style\="padding\: 0 4px">如果您改變主意了，您可從外掛總管安裝新功能。</p> <p style\="padding\: 0 4px">Learn how these new features can improve your Jenkins experience by <a rel\="noopener noreferrer" target\="_blank" href\="https\://www.jenkins.io/2.0/">造訪首頁</a>以了解這些新功能如何提升您的 Jenkins 使用體驗。</p>
 installWizard_upgrading_title=正在安裝外掛
 installWizard_upgradeComplete_finishButtonLabel=完成
diff --git a/core/src/main/resources/jenkins/management/AdministrativeMonitorsDecorator/resources.css b/core/src/main/resources/jenkins/management/AdministrativeMonitorsDecorator/resources.css
index 62ba95f86ae3..80fe16c8d8e7 100644
--- a/core/src/main/resources/jenkins/management/AdministrativeMonitorsDecorator/resources.css
+++ b/core/src/main/resources/jenkins/management/AdministrativeMonitorsDecorator/resources.css
@@ -106,8 +106,7 @@
   margin: 0;
 }
 
-.am-container .am-message .alert form,
-.am-container .am-message .jenkins-alert form {
+.am-container .am-message .alert form {
   position: relative;
   float: right;
   margin: -6px 0 0 0 !important;
@@ -116,13 +115,11 @@
   padding-left: 0.5rem;
 }
 
-.am-container .am-message .alert form span,
-.am-container .am-message .jenkins-alert form span {
+.am-container .am-message .alert form span {
   margin: 0 0 0 4px !important;
 }
 
-.am-container .am-message .alert,
-.am-container .am-message .jenkins-alert {
+.am-container .am-message .alert {
   margin-bottom: 0 !important;
 }
 
@@ -151,19 +148,19 @@
   text-decoration: var(--link-text-decoration--hover);
 }
 
-.am-container .am-list .jenkins-alert-success a {
+.am-container .am-list .alert-success a {
   color: var(--alert-success-text-color);
 }
 
-.am-container .am-list .jenkins-alert-info a {
+.am-container .am-list .alert-info a {
   color: var(--alert-info-text-color);
 }
 
-.am-container .am-list .jenkins-alert-warning a {
+.am-container .am-list .alert-warning a {
   color: var(--alert-warning-text-color);
 }
 
-.am-container .am-list .jenkins-alert-danger a {
+.am-container .am-list .alert-danger a {
   color: var(--alert-danger-text-color);
 }
 
diff --git a/core/src/main/resources/jenkins/model/BuiltInNodeMigration/message.jelly b/core/src/main/resources/jenkins/model/BuiltInNodeMigration/message.jelly
index b9ea4fd3ed9c..82037ac2e4f5 100644
--- a/core/src/main/resources/jenkins/model/BuiltInNodeMigration/message.jelly
+++ b/core/src/main/resources/jenkins/model/BuiltInNodeMigration/message.jelly
@@ -1,6 +1,6 @@
 <?jelly escape-by-default='true'?>
 <j:jelly xmlns:j="jelly:core" xmlns:st="jelly:stapler" xmlns:d="jelly:define" xmlns:l="/lib/layout" xmlns:t="/lib/hudson" xmlns:f="/lib/form">
-    <div class="jenkins-alert jenkins-alert-warning">
+    <div class="alert alert-warning">
         <form method="post" action="${rootURL}/${it.url}/act" name="${it.id}">
             <f:submit name="yes" value="${%Apply Migration}"/>
             <f:submit name="no" value="${%Dismiss}"/>
diff --git a/core/src/main/resources/jenkins/model/Jenkins/EnforceSlaveAgentPortAdministrativeMonitor/message.jelly b/core/src/main/resources/jenkins/model/Jenkins/EnforceSlaveAgentPortAdministrativeMonitor/message.jelly
index 92bd204e2528..f33ac400a1f4 100644
--- a/core/src/main/resources/jenkins/model/Jenkins/EnforceSlaveAgentPortAdministrativeMonitor/message.jelly
+++ b/core/src/main/resources/jenkins/model/Jenkins/EnforceSlaveAgentPortAdministrativeMonitor/message.jelly
@@ -23,7 +23,7 @@ THE SOFTWARE.
 -->
 <?jelly escape-by-default='true'?>
 <j:jelly xmlns:j="jelly:core" xmlns:st="jelly:stapler" xmlns:d="jelly:define" xmlns:l="/lib/layout" xmlns:t="/lib/hudson" xmlns:f="/lib/form" xmlns:i="jelly:fmt">
-  <div class="jenkins-alert jenkins-alert-warning">
+  <div class="alert alert-warning">
     <form method="post" action="${rootURL}/${it.url}/act" name="${it.id}">
       <f:submit name="reset" value="${%reset(it.expectedPort)}"/>
     </form>
diff --git a/core/src/main/resources/jenkins/model/Jenkins/downgrade.jelly b/core/src/main/resources/jenkins/model/Jenkins/downgrade.jelly
index d5384588afc8..c18a88125db5 100644
--- a/core/src/main/resources/jenkins/model/Jenkins/downgrade.jelly
+++ b/core/src/main/resources/jenkins/model/Jenkins/downgrade.jelly
@@ -25,7 +25,7 @@ THE SOFTWARE.
 <?jelly escape-by-default='true'?>
 <j:jelly xmlns:j="jelly:core" xmlns:st="jelly:stapler" xmlns:d="jelly:define" xmlns:l="/lib/layout" xmlns:t="/lib/hudson" xmlns:f="/lib/form">
 <j:if test="${app.updateCenter.downgradable}">
-<div class="jenkins-alert jenkins-alert-warning">
+<div class="alert alert-warning">
   ${%Restore the previous version of Jenkins}
   <form method="post" action="${rootURL}/updateCenter/downgrade">
     <f:submit value="${%buttonText(app.updateCenter.backupVersion)}"/>
diff --git a/core/src/main/resources/jenkins/monitor/JavaVersionRecommendationAdminMonitor/message.jelly b/core/src/main/resources/jenkins/monitor/JavaVersionRecommendationAdminMonitor/message.jelly
index de3c496235bd..0265cf145a72 100644
--- a/core/src/main/resources/jenkins/monitor/JavaVersionRecommendationAdminMonitor/message.jelly
+++ b/core/src/main/resources/jenkins/monitor/JavaVersionRecommendationAdminMonitor/message.jelly
@@ -24,7 +24,7 @@ THE SOFTWARE.
 
 <?jelly escape-by-default='true'?>
 <j:jelly xmlns:j="jelly:core" xmlns:l="/lib/layout" xmlns:f="/lib/form">
-    <div class="jenkins-alert jenkins-alert-${it.severityAsString}">
+    <div class="alert alert-${it.severityAsString}">
         <form id="JavaVersionRecommendationAdminMonitor" method="post" action="${rootURL}/${it.url}/act" name="${it.id}">
             <f:submit name="yes" value="${%More Info}"/>
             <l:isAdmin>
diff --git a/core/src/main/resources/jenkins/monitor/OperatingSystemEndOfLifeAdminMonitor/message.jelly b/core/src/main/resources/jenkins/monitor/OperatingSystemEndOfLifeAdminMonitor/message.jelly
index 096a8827f3cc..e61f7a4e88e2 100644
--- a/core/src/main/resources/jenkins/monitor/OperatingSystemEndOfLifeAdminMonitor/message.jelly
+++ b/core/src/main/resources/jenkins/monitor/OperatingSystemEndOfLifeAdminMonitor/message.jelly
@@ -25,7 +25,7 @@ THE SOFTWARE.
 
 <?jelly escape-by-default='true'?>
 <j:jelly xmlns:j="jelly:core" xmlns:l="/lib/layout" xmlns:f="/lib/form">
-    <div class="jenkins-alert jenkins-alert-danger">
+    <div class="alert alert-danger">
         <form id="${it.id}" method="post" action="${rootURL}/${it.url}/act" name="${it.id}">
             <f:submit name="yes" value="${%More Info}"/>
             <l:isAdmin>
diff --git a/core/src/main/resources/jenkins/security/RekeySecretAdminMonitor/message.groovy b/core/src/main/resources/jenkins/security/RekeySecretAdminMonitor/message.groovy
index 5ecf28df34c4..a0d22cca1196 100644
--- a/core/src/main/resources/jenkins/security/RekeySecretAdminMonitor/message.groovy
+++ b/core/src/main/resources/jenkins/security/RekeySecretAdminMonitor/message.groovy
@@ -26,22 +26,22 @@ package jenkins.security.RekeySecretAdminMonitor
 def f = namespace(lib.FormTagLib)
 
 if (!my.isDone()) {
-    div(class:"jenkins-alert jenkins-alert-danger") {
+    div(class:"alert alert-danger") {
         raw _("pleaseRekeyAsap", app.rootDir, my.url)
     }
 }
 
 if (my.isFixingActive()) {
-    div(class:"jenkins-alert jenkins-alert-info") {
+    div(class:"alert alert-info") {
         raw _("rekeyInProgress", my.url)
     }
 } else if (my.logFile.exists()) {
     if (my.isDone()) {
-        div(class:"jenkins-alert jenkins-alert-info") {
+        div(class:"alert alert-info") {
             raw _("rekeySuccessful", my.url)
         }
     } else {
-        div(class:"jenkins-alert jenkins-alert-warning") {
+        div(class:"alert alert-warning") {
             raw _("rekeyHadProblems", my.url)
         }
     }
diff --git a/core/src/main/resources/jenkins/security/ResourceDomainRecommendation/message.groovy b/core/src/main/resources/jenkins/security/ResourceDomainRecommendation/message.groovy
index cb31f6204049..d1267f9cca3c 100644
--- a/core/src/main/resources/jenkins/security/ResourceDomainRecommendation/message.groovy
+++ b/core/src/main/resources/jenkins/security/ResourceDomainRecommendation/message.groovy
@@ -27,7 +27,7 @@ def f = namespace(lib.FormTagLib)
 def l = namespace(lib.LayoutTagLib)
 
 dl {
-    div(class: "jenkins-alert jenkins-alert-info") {
+    div(class: "alert alert-info") {
         a(name: "resource-root-url")
         l.isAdmin() {
           form(method: "post", action: "${rootURL}/${my.url}/act") {
diff --git a/core/src/main/resources/jenkins/security/UpdateSiteWarningsMonitor/message.groovy b/core/src/main/resources/jenkins/security/UpdateSiteWarningsMonitor/message.groovy
index 56cbb0bb4ddd..27f8d66da354 100644
--- a/core/src/main/resources/jenkins/security/UpdateSiteWarningsMonitor/message.groovy
+++ b/core/src/main/resources/jenkins/security/UpdateSiteWarningsMonitor/message.groovy
@@ -64,7 +64,7 @@ def listWarnings(warnings, boolean core) {
 def coreWarnings = my.activeCoreWarnings
 def pluginWarnings = my.activePluginWarningsByPlugin
 
-div(class: "jenkins-alert jenkins-alert-danger", role: "alert") {
+div(class: "alert alert-danger", role: "alert") {
 
     l.isAdmin() {
         form(method: "post", action: "${rootURL}/${my.url}/forward") {
diff --git a/core/src/main/resources/jenkins/security/apitoken/ApiTokenPropertyDisabledDefaultAdministrativeMonitor/message.jelly b/core/src/main/resources/jenkins/security/apitoken/ApiTokenPropertyDisabledDefaultAdministrativeMonitor/message.jelly
index 0ff96ab3ebf4..923a29aa38c6 100644
--- a/core/src/main/resources/jenkins/security/apitoken/ApiTokenPropertyDisabledDefaultAdministrativeMonitor/message.jelly
+++ b/core/src/main/resources/jenkins/security/apitoken/ApiTokenPropertyDisabledDefaultAdministrativeMonitor/message.jelly
@@ -23,7 +23,7 @@ THE SOFTWARE.
 -->
 <?jelly escape-by-default='true'?>
 <j:jelly xmlns:j="jelly:core" xmlns:f="/lib/form">
-    <div class="jenkins-alert jenkins-alert-warning">
+    <div class="alert alert-warning">
         <form method="post" action="${rootURL}/${it.url}/act" name="${it.id}">
             <f:submit name="yes" value="${%Disable automatic generation of legacy API tokens}"/>
             <f:submit name="no" value="${%Dismiss}"/>
diff --git a/core/src/main/resources/jenkins/security/apitoken/ApiTokenPropertyEnabledNewLegacyAdministrativeMonitor/message.jelly b/core/src/main/resources/jenkins/security/apitoken/ApiTokenPropertyEnabledNewLegacyAdministrativeMonitor/message.jelly
index 0c11b2c72142..2d57564a4761 100644
--- a/core/src/main/resources/jenkins/security/apitoken/ApiTokenPropertyEnabledNewLegacyAdministrativeMonitor/message.jelly
+++ b/core/src/main/resources/jenkins/security/apitoken/ApiTokenPropertyEnabledNewLegacyAdministrativeMonitor/message.jelly
@@ -23,7 +23,7 @@ THE SOFTWARE.
 -->
 <?jelly escape-by-default='true'?>
 <j:jelly xmlns:j="jelly:core" xmlns:f="/lib/form">
-    <div class="jenkins-alert jenkins-alert-warning">
+    <div class="alert alert-warning">
         <form method="post" action="${rootURL}/${it.url}/act" name="${it.id}">
             <f:submit name="yes" value="${%Prevent users from manually creating legacy API tokens}"/>
             <f:submit name="no" value="${%Dismiss}"/>
diff --git a/core/src/main/resources/jenkins/security/apitoken/LegacyApiTokenAdministrativeMonitor/message.jelly b/core/src/main/resources/jenkins/security/apitoken/LegacyApiTokenAdministrativeMonitor/message.jelly
index 376eb6ca57ca..05c3d673415f 100644
--- a/core/src/main/resources/jenkins/security/apitoken/LegacyApiTokenAdministrativeMonitor/message.jelly
+++ b/core/src/main/resources/jenkins/security/apitoken/LegacyApiTokenAdministrativeMonitor/message.jelly
@@ -23,7 +23,7 @@ THE SOFTWARE.
 -->
 <?jelly escape-by-default='true'?>
 <j:jelly xmlns:j="jelly:core">
-    <div class="jenkins-alert jenkins-alert-warning">
+    <div class="alert alert-warning">
         ${%warningMessage(rootURL, it.url)}
     </div>
 </j:jelly>
diff --git a/core/src/main/resources/jenkins/security/csrf/CSRFAdministrativeMonitor/message.jelly b/core/src/main/resources/jenkins/security/csrf/CSRFAdministrativeMonitor/message.jelly
index 392a1a8677bf..14df02a36328 100644
--- a/core/src/main/resources/jenkins/security/csrf/CSRFAdministrativeMonitor/message.jelly
+++ b/core/src/main/resources/jenkins/security/csrf/CSRFAdministrativeMonitor/message.jelly
@@ -23,7 +23,7 @@ THE SOFTWARE.
 -->
 <?jelly escape-by-default='true'?>
 <j:jelly xmlns:j="jelly:core" xmlns:f="/lib/form">
-    <div class="jenkins-alert jenkins-alert-warning">
+    <div class="alert alert-warning">
         <form method="post" action="${rootURL}/${it.url}/disable">
             <f:submit value="${%Dismiss}"/>
         </form>
diff --git a/test/src/test/java/hudson/PluginManagerTest.java b/test/src/test/java/hudson/PluginManagerTest.java
index 49d4a4c88e72..c2fc5dd8721e 100644
--- a/test/src/test/java/hudson/PluginManagerTest.java
+++ b/test/src/test/java/hudson/PluginManagerTest.java
@@ -793,7 +793,7 @@ public void noInjectionOnAvailablePluginsPage() throws Exception {
 
             PluginManagerUtil.getCheckForUpdatesButton(p).click();
             HtmlPage available = wc.goTo("pluginManager/available");
-            assertTrue(available.querySelector(".jenkins-alert-danger")
+            assertTrue(available.querySelector(".alert-danger")
                     .getTextContent().contains("This plugin is built for Jenkins 9999999"));
             wc.waitForBackgroundJavaScript(100);
 
diff --git a/war/src/main/js/templates/plugin-manager/available.hbs b/war/src/main/js/templates/plugin-manager/available.hbs
index 115a7b4d8e21..2810b7a13d9b 100644
--- a/war/src/main/js/templates/plugin-manager/available.hbs
+++ b/war/src/main/js/templates/plugin-manager/available.hbs
@@ -31,12 +31,12 @@
                 </div>
             {{/if}}
             {{#if this.newerCoreRequired }}
-                <div class="jenkins-alert jenkins-alert-danger">
+                <div class="alert alert-danger">
                     {{{ this.newerCoreRequired }}}
                 </div>
             {{/if}}
             {{#if this.unresolvedSecurityWarnings }}
-                <div class="jenkins-alert jenkins-alert-danger">
+                <div class="alert alert-danger">
                     {{ this.unresolvedSecurityWarnings.text }}
                     <ul>
                         {{#each this.unresolvedSecurityWarnings.warnings}}
@@ -50,12 +50,12 @@
                 </div>
             {{/if}}
             {{#if this.deprecated }}
-                <div class="jenkins-alert jenkins-alert-warning">
+                <div class="alert alert-warning">
                     {{{ this.deprecated }}}
                 </div>
             {{/if}}
             {{#if this.adoptMe }}
-                <div class="jenkins-alert jenkins-alert-warning">
+                <div class="alert alert-warning">
                     {{{ this.adoptMe }}}
                 </div>
             {{/if}}
diff --git a/war/src/main/scss/components/_alert.scss b/war/src/main/scss/components/_alert.scss
deleted file mode 100644
index 16be23858b32..000000000000
--- a/war/src/main/scss/components/_alert.scss
+++ /dev/null
@@ -1,55 +0,0 @@
-.alert,
-.jenkins-alert {
-  font-size: var(--font-size-sm);
-  padding: 15px;
-  margin-bottom: 20px;
-  border: 1px solid transparent;
-  border-radius: 10px;
-
-  strong {
-    font-weight: 500;
-  }
-
-  a {
-    color: inherit;
-    text-decoration: underline;
-
-    &:hover,
-    &:focus,
-    &:active {
-      text-decoration: underline;
-    }
-  }
-
-  &-success {
-    color: var(--alert-success-text-color);
-    background-color: var(--alert-success-bg-color);
-    border-color: var(--alert-success-border-color);
-  }
-
-  &-info {
-    color: var(--alert-info-text-color);
-    background-color: var(--alert-info-bg-color);
-    border-color: var(--alert-info-border-color);
-  }
-
-  &-warning {
-    color: var(--alert-warning-text-color);
-    background-color: var(--alert-warning-bg-color);
-    border-color: var(--alert-warning-border-color);
-
-    p {
-      color: var(--alert-warning-text-color);
-    }
-  }
-
-  &-danger {
-    color: var(--alert-danger-text-color);
-    background-color: var(--alert-danger-bg-color);
-    border-color: var(--alert-danger-border-color);
-
-    p {
-      color: var(--alert-danger-text-color);
-    }
-  }
-}
diff --git a/war/src/main/scss/pages/_manage-jenkins.scss b/war/src/main/scss/pages/_manage-jenkins.scss
index 706fe2e49a09..7b4f364cf779 100644
--- a/war/src/main/scss/pages/_manage-jenkins.scss
+++ b/war/src/main/scss/pages/_manage-jenkins.scss
@@ -34,29 +34,32 @@
   content: ": ";
 }
 
-.manage-messages .alert,
-.manage-messages .jenkins-alert {
-  &:last-of-type {
+.manage-messages {
+  .alert:last-of-type {
     margin-bottom: 30px;
   }
+}
 
-  a {
-    text-decoration: underline;
-  }
+.manage-messages .alert a {
+  text-decoration: underline;
+}
 
-  form {
-    position: relative;
-    float: right;
-    margin: -6px 0 0 !important;
-    display: flex;
-    gap: 0.5rem;
+.manage-messages .alert a:hover {
+  text-decoration: underline;
+}
 
-    & > div {
-      display: contents;
-    }
+.manage-messages .alert form {
+  position: relative;
+  float: right;
+  margin: -6px 0 0 !important;
+  display: flex;
+  gap: 0.5rem;
 
-    span {
-      margin: 0 0 0 4px !important;
-    }
+  & > div {
+    display: contents;
   }
 }
+
+.manage-messages .alert form span {
+  margin: 0 0 0 4px !important;
+}
diff --git a/war/src/main/scss/simple-page.scss b/war/src/main/scss/simple-page.scss
index a627d6c95e9e..c80f6e1303d7 100644
--- a/war/src/main/scss/simple-page.scss
+++ b/war/src/main/scss/simple-page.scss
@@ -97,7 +97,6 @@
   border-color: var(--danger-color, #c4000a);
 }
 
-.simple-page .alert,
-.simple-page .jenkins-alert {
+.simple-page .alert {
   color: var(--danger-color, #c4000a);
 }