Adjust size of file name input, start updaing high contrast theme

Author: catarak

client/styles/abstracts/_variables.scss

@@ -188,7 +188,7 @@ $themes: (
     heading-text-color: #e1e1e1,
     secondary-text-color: #e1e1e1,
     inactive-text-color: #f2f2f2,
-    background-color: #333,
+    background-color: $darker,
     button-background-color: $white,
     button-color: $black,
     button-border-color: #979797,

client/styles/components/_sidebar.scss

@@ -173,7 +173,7 @@
   display: none;
   padding: 0;
   border: 0;
-  width: calc(100% - #{100 / $base-font-size}rem);
+  width: calc(100% - #{63 / $base-font-size}rem);
   .sidebar__file-item--editing & {
     display: inline-block;
   }