Bug 1409340 - Ensure light theme on Windows 7 gets dark hover state on tabs. r=dao

MozReview-Commit-ID: H1ki0EotjSq

--HG--
extra : rebase_source : bae2d73daeba723b147fb706dd27440ef526fdf5

browser/themes/windows/compacttheme.css

@@ -46,6 +46,16 @@
     .tabbrowser-tab {
       color: var(--chrome-color) !important;
     }
+
+    /* Because we're forcing the tabs toolbar to be [brighttext] to
+     * get white toolbar button icons, we need to manually set the
+     * correct color for the tab hover state for the light theme. */
+    .tabbrowser-tab:hover > .tab-stack > .tab-background:not([selected=true]):-moz-lwtheme-darktext {
+      background-color: rgba(0,0,0,.1) !important;
+    }
+    .tabbrowser-tab:hover > .tab-stack > .tab-background > .tab-line:not([selected=true]):-moz-lwtheme-darktext {
+      background-color: rgba(0,0,0,.2) !important;
+    }
   }
 }