Remove selection overrides

Having the browser text selection behaviour change when it moves over
a highlight is extremely confusing. This change removes that behaviour,
the highlight mixin and brings the PDFjs override file inline with
common.css

h/static/styles/common.scss

@@ -326,16 +326,4 @@ html {
 .search-hl-active {
   background: $highlight-color;
   box-shadow:3px 3px 4px -1px #999999;
-  &::-moz-selection {
-    background: $highlight-color;
-    box-shadow:3px 3px 4px #999999;
-  }
-  &::-moz-selection, &::-moz-window-inactive, &::window-inactive {
-    background: $highlight-color;
-    box-shadow:3px 3px 4px #999999;
-  }
-  &::selection, &::selection:window-inactive {
-    background: $highlight-color;
-    box-shadow:3px 3px 4px #999999;
-  }
 }

h/static/styles/inject.scss

 @import 'base';
-@import 'mixins/highlight';
 @import 'mixins/icons';
 @import 'compass/css3/user-interface';
 @import 'compass/layout/stretching';
@@ -76,22 +75,23 @@ $base-font-size: 14px;
 //HIGHLIGHTS////////////////////////////////
 .annotator-highlights-always-on {
   .annotator-hl {
-    @include highlight($highlight-color);
+    background-color: $highlight-color;
   }
 
   .annotator-hl .annotator-hl {
-    @include highlight($highlight-color-second);
+    background-color: $highlight-color-second;
   }
 
   .annotator-hl .annotator-hl .annotator-hl {
-    @include highlight($highlight-color-third);
+    background-color: $highlight-color-third;
   }
 }
 
 .annotator-hl.annotator-hl-focused {
-  @include highlight($highlight-color-focus !important);
+  background-color: $highlight-color-focus !important;
+
   .annotator-hl {
-    @include highlight(transparent !important);
+    background-color: transparent !important;
   }
 }
 

h/static/styles/mixins/highlight.scss

-@import 'compass/css3/selection';
-
-@mixin highlight($color) {
-  background: $color;
-  @include selection {
-    background: $color;
-    &:window-inactive {
-      background: $color;
-    }
-  }
-}

h/static/styles/pdfjs-overrides.scss

@@ -5,18 +5,6 @@
 // PDFjs plugin provides a compatibility class to the PDFjs container that
 // we can use to detect this.
 .has-transparent-text-layer {
-  .annotator-hl {
-    &::-moz-selection {
-      background: rgba($highlight-color, 1);
-    }
-    &::-moz-selection, &::-moz-window-inactive, &::window-inactive {
-      background: rgba($highlight-color, 1);
-    }
-    &::selection, &::selection:window-inactive {
-      background: rgba($highlight-color, 1);
-    }
-  }
-
   .annotator-highlights-always-on & .annotator-hl {
     background: rgba($highlight-color, 1);
 
@@ -29,8 +17,11 @@
     }
   }
 
-  .annotator-hl-focused,
-  .annotator-highlights-always-on & .annotator-hl.annotator-hl-focused {
-    background-color: rgba($highlight-color-focus, 1);
+  .annotator-hl.annotator-hl-focused {
+    background-color: rgb(192, 236, 253);
+
+    .annotator-hl {
+      background-color: transparent !important;
+    }
   }
 }