fix(a11y): various issues with contrast ratios (#635)

Fixes #398. Reverts #399.

Author: Splaktar

material.angular.io/src/app/pages/component-sidenav/_component-sidenav-theme.scss

@@ -35,7 +35,7 @@
 
       &.docs-component-viewer-sidenav-item-selected,
       &:hover {
-        color: mat-color($primary);
+        color: mat-color($primary, if($is-dark-theme, 200, default));
       }
     }
   }

material.angular.io/src/app/pages/guide-list/_guide-list-theme.scss

@@ -6,8 +6,9 @@
   $warn: map-get($theme, warn);
   $background: map-get($theme, background);
   $foreground: map-get($theme, foreground);
+  $is-dark-theme: map-get($theme, is-dark);
 
   .docs-guide-list .docs-guide-item {
-    color: mat-color($primary);
+    color: mat-color($primary, if($is-dark-theme, 200, default));
   }
 }

material.angular.io/src/app/shared/table-of-contents/_table-of-contents-theme.scss

@@ -4,6 +4,7 @@
   $warn: map-get($theme, warn);
   $background: map-get($theme, background);
   $foreground: map-get($theme, foreground);
+  $is-dark-theme: map-get($theme, is-dark);
 
   .docs-toc-container {
     border-left: solid 4px mat-color($primary);
@@ -14,7 +15,7 @@
 
       &:hover,
       &.docs-active {
-        color: mat-color($primary);
+        color: mat-color($primary, if($is-dark-theme, 200, default));
       }
     }
   }

material.angular.io/src/highlightjs/material-dark.scss

@@ -18,7 +18,7 @@ Orginal Style from https://github.com/Kelbster/highlightjs-material-dark-theme
 }
 
 .hljs-comment {
-  color: #656565;
+  color: #9E9E9E;
   font-style: italic;
 }
 

material.angular.io/src/highlightjs/material-light.scss

@@ -17,7 +17,7 @@
 }
 
 .hljs-comment {
-  color: #B0BEC5;
+  color: #616161;
   font-style: italic;
 }
 

material.angular.io/src/styles/_api-theme.scss

@@ -9,9 +9,24 @@
   $foreground: map-get($theme, foreground);
   $is-dark-theme: map-get($theme, is-dark);
 
-  .docs-api-method-returns-type,
-  .docs-api-method-parameter-type {
-    color: mat-color($primary, darker);
+  @if $is-dark-theme {
+    .docs-api-method-name-cell {
+      color: mat-color($primary, 200);
+    }
+
+    .docs-api-method-returns-type,
+    .docs-api-method-parameter-type {
+      color: mat-color($primary, 200);
+    }
+  } @else {
+    .docs-api-method-name-cell {
+      color: mat-color($primary, 800);
+    }
+
+    .docs-api-method-returns-type,
+    .docs-api-method-parameter-type {
+      color: mat-color($primary, darker);
+    }
   }
 
   // Force the top-level API docs header to be hidden, since this is already

material.angular.io/src/styles/_markdown-theme.scss

@@ -12,7 +12,7 @@
 
   .docs-markdown {
     a {
-      color: mat-color($primary);
+      color: mat-color($primary, if($is-dark-theme, 200, default));
     }
 
     pre {