diff --git a/packages/core/src/browser/style/tabs.css b/packages/core/src/browser/style/tabs.css
index f5e9cc223a208..940ec8b5f78fc 100644
--- a/packages/core/src/browser/style/tabs.css
+++ b/packages/core/src/browser/style/tabs.css
@@ -82,13 +82,12 @@
     border-right: 1px solid var(--theia-tab-border);
     background: var(--theia-tab-inactiveBackground);
     color: var(--theia-tab-inactiveForeground);
-    border-top: 1px solid transparent;
 }
 
 #theia-main-content-panel .p-TabBar .p-TabBar-tab.p-mod-current {
     background: var(--theia-tab-activeBackground);
     color: var(--theia-tab-activeForeground);
-    border-top: 1px solid var(--theia-tab-activeBorderTop);
+    box-shadow: 0 1px 0 var(--theia-tab-activeBorderTop) inset, 0 -1px 0 var(--theia-tab-activeBorder) inset;
 }
 
 #theia-main-content-panel .p-TabBar:not(.theia-tabBar-active) .p-TabBar-tab .p-TabBar-tabLabel {