diff --git a/runtime/themes/horizon-dark.toml b/runtime/themes/horizon-dark.toml
index 5d1c34cde99c..aec113dfa098 100644
--- a/runtime/themes/horizon-dark.toml
+++ b/runtime/themes/horizon-dark.toml
@@ -4,7 +4,7 @@ constant = "purple"
 "constant.numeric" = "orange"
 "constant.builtin" = "orange"
 variable = "red"
-comment = "green"
+comment = "light-gray"
 special = "purple"
 "punctuation.bracket" = "purple"
 keyword = "purple"
@@ -13,45 +13,62 @@ label = "orange"
 type = "orange"
 namespace = "orange"
 
-# UI
+# User Interface
 "ui.background" = { bg = "bg", fg = "gray" }
-"ui.background.separator" = "blue-gray"
+"ui.background.separator" = "light-gray"
 "ui.text" = "white"
 "ui.text.focus" = "green"
 "ui.text.inactive" = "selection"
-"ui.text.info" = "white"
+"ui.text.info" = "orange"
 "ui.cursor" = { modifiers = ["reversed"] }
 "ui.cursor.primary" = { modifiers = ["reversed"] }
 "ui.cursor.match" = { bg = "selection" }
 "ui.gutter" = "gray"
-"ui.gutter.selected" = "blue-gray"
+"ui.gutter.selected" = "light-gray"
 "ui.selection" = { bg = "selection" }
-"ui.virtual.indent-guide" = { fg = "gray" }
-"ui.virtual.whitespace" = { fg = "blue-gray" }
-"ui.statusline" = { bg = "dark-bg", fg = "blue-gray" }
-"ui.popup" = { bg = "bg", fg = "gray" }
-"ui.help" = { bg = "bg", fg = "white" }
-"ui.menu" = { bg = "bg", fg = "white" }
-"ui.menu.selected" = { bg = "bg", fg = "orange" }
+"ui.virtual.indent-guide" = { fg = "gray"}
+"ui.virtual.whitespace" = { fg = "light-gray"}
+"ui.statusline" = { bg = "dark-bg", fg = "light-gray" }
+"ui.popup" = { bg = "dark-bg", fg = "orange" }
+"ui.help" = { bg = "dark-bg", fg = "orange" }
+"ui.menu" = { bg = "dark-bg", fg = "light-gray" }
+"ui.menu.selected" = { bg = "selection", fg = "orange" }
 "ui.window" = "selection"
-"ui.bufferline" = { bg = "dark-bg", fg = "blue-gray" }
+"ui.bufferline" = { bg = "dark-bg", fg = "light-gray" }
 "ui.bufferline.active" = { bg = "dark-bg", fg = "orange" }
 
+# Diagnostics
 "diagnostic" = { underline = { style = "curl" } }
 "diagnostic.hint" = { underline = { color = "green", style = "curl" } }
 "diagnostic.info" = { underline = { color = "blue", style = "curl" } }
-"diagnostics.error" = { underline = { color = "red", style = "curl" } }
-"diagnostics.warning" = { underline = { color = "orange", style = "curl" } }
+"diagnostics.error" = { underline = { color = "red", style = "curl"} }
+"diagnostics.warning" = { underline = { color = "orange", style = "curl"} }
 
 warning = { fg = "orange", modifiers = ["bold"] }
 error = { fg = "red", modifiers = ["bold"] }
 info = { fg = "blue", modifiers = ["bold"] }
 hint = { fg = "green", modifiers = ["bold"] }
 
+# Markup
+"markup.heading" = "pink"
+"markup.list" = "light-gray"
+"markup.list.checked" = "green"
+"markup.list.unchecked" = "light-gray"
+"markup.bold" = { modifiers = ["bold"] }
+"markup.italic" = { modifiers = ["italic"] }
+"markup.strikethrough" = { modifiers = ["crossed_out"] }
+"markup.link" = "blue"
+"markup.quote" = "orange"
+"markup.raw" = "orange"
+
+"diff.plus" =  "green"
+"diff.minus" = "red"
+"diff.delta" = "orange"
+
 [palette]
 white = "#D5D8DA"
 gray = "#2E303E"
-blue-gray = "#6C6F93"
+light-gray = "#6C6F93"
 bg = "#1C1E26"
 dark-bg = "#16161C"
 pink = "#EE64AE"