fixup! Bug 30237: Add v3 onion services client authentication prompt

Bug 41659: Add canonical color definitions to base-browser

browser/components/onionservices/content/authPreferences.css

 /* Copyright (c) 2020, The Tor Project, Inc. */
 
-@import url("chrome://branding/content/tor-styles.css");
+@import url("chrome://browser/skin/browser-colors.css");
 
 #torOnionServiceKeys-overview-container {
   margin-right: 30px;
@@ -19,6 +19,6 @@
   margin-right: 4px;
   list-style-image: url("chrome://global/skin/icons/warning.svg");
   -moz-context-properties: fill;
-  fill: var(--torbrowser-warning);
+  fill: var(--warning-color);
   visibility: hidden;
 }