--- a/devtools/client/application/src/components/App.css
+++ b/devtools/client/application/src/components/App.css
@@ -18,24 +18,24 @@ h1 {
 
 a {
   margin: 0 10px;
 }
 
 a,
 a:hover,
 a:visited {
-  color: var(--blue-60) !important;
+  color: var(--theme-highlight-blue) !important;
   cursor: pointer;
 }
 
 a.disabled,
 a.disabled:hover,
 a.disabled:visited {
-  color: var(--grey-30) !important;
+  opacity: 0.5 !important;
   cursor: default;
 }
 
 /*
  * The current layout of the application panel is
  *
  *  +---------------------------------------------+
  *  | (header) "Service workers"                  |

--- a/devtools/client/application/src/components/Worker.js
+++ b/devtools/client/application/src/components/Worker.js
@@ -118,17 +118,18 @@ class Worker extends Component {
       button({
         onClick: this.unregister,
         className: "devtools-button worker__unregister-button js-unregister-button",
         "data-standalone": true
       },
         Strings.GetStringFromName("unregister"))
       : null;
 
-    const debugLinkDisabled = this.isRunning() ? "" : "worker__debug-link--disabled";
+    const debugLinkDisabled = this.isRunning() ? "" : "disabled";
+
     const debugLink = a({
       onClick: this.isRunning() ? this.debug : null,
       title: this.isRunning() ? null : "Only running service workers can be debugged",
       className: `${debugLinkDisabled} worker__debug-link js-debug-link`
     },
       Strings.GetStringFromName("debug"));
 
     const startLink = !this.isRunning() ?