diff --git a/github-dark.css b/github-dark.css
index ec786ca99..fbf00fa95 100644
--- a/github-dark.css
+++ b/github-dark.css
@@ -10576,6 +10576,9 @@
   .blob-code, .blob-code-inner {
     color: var(--ghd-code-color, #ccc) !important;
   }
+  .cm-tab {
+    overflow: hidden !important;
+  }
 }
 @-moz-document regexp("^https://www\.zuora\.com.*github\.com.*$") {
   /* Styles the payment form iframe */
diff --git a/github-dark.user.css b/github-dark.user.css
index b0e58025c..340249b09 100644
--- a/github-dark.user.css
+++ b/github-dark.user.css
@@ -160,36 +160,57 @@
   pre, .highlight, .diff-table, .tab-size {
     tab-size: 2 !important;
     -moz-tab-size: 2 !important;
+  }
+  .cm-tab {
+    width: 2ch !important;
   } EOT;
   3 "3" <<<EOT
   pre, .highlight, .diff-table, .tab-size {
     tab-size: 3 !important;
     -moz-tab-size: 3 !important;
+  }
+  .cm-tab {
+    width: 3ch !important;
   } EOT;
   4 "4" <<<EOT
   pre, .highlight, .diff-table, .tab-size {
     tab-size: 4 !important;
     -moz-tab-size: 4 !important;
+  }
+  .cm-tab {
+    width: 4ch !important;
   } EOT;
   5 "5" <<<EOT
   pre, .highlight, .diff-table, .tab-size {
     tab-size: 5 !important;
     -moz-tab-size: 5 !important;
+  }
+  .cm-tab {
+    width: 5ch !important;
   } EOT;
   6 "6" <<<EOT
   pre, .highlight, .diff-table, .tab-size {
     tab-size: 6 !important;
     -moz-tab-size: 6 !important;
+  }
+  .cm-tab {
+    width: 6ch !important;
   } EOT;
   7 "7" <<<EOT
   pre, .highlight, .diff-table, .tab-size {
     tab-size: 7 !important;
     -moz-tab-size: 7 !important;
+  }
+  .cm-tab {
+    width: 7ch !important;
   } EOT;
   8 "8" <<<EOT
   pre, .highlight, .diff-table, .tab-size {
     tab-size: 8 !important;
     -moz-tab-size: 8 !important;
+  }
+  .cm-tab {
+    width: 8ch !important;
   } EOT;
 }
 @advanced text font-choice "Code Font" "Menlo"
@@ -10036,6 +10057,9 @@
   .blob-code, .blob-code-inner {
     color: var(--ghd-code-color, #ccc) !important;
   }
+  .cm-tab {
+    overflow: hidden !important;
+  }
 }
 @-moz-document regexp("^https://www\.zuora\.com.*github\.com.*$") {
   /* Styles the payment form iframe */
diff --git a/tools/usercss.js b/tools/usercss.js
index e95b88c38..36e5ebb20 100644
--- a/tools/usercss.js
+++ b/tools/usercss.js
@@ -72,6 +72,9 @@ function makeTabs(css) {
   pre, .highlight, .diff-table, .tab-size {
     tab-size: ${tab} !important;
     -moz-tab-size: ${tab} !important;
+  }
+  .cm-tab {
+    width: ${tab}ch !important;
   } EOT;`);
   });
   return css.replace("  {{tab-sizes}}", tabs.join("\n"));