Improved documentation accessibility (#118):

* better contrast.

support/documentation/layouts/partials/custom-header.html

@@ -5,7 +5,7 @@
   --MAIN-TEXT-color:#000; /* Color of text by default */
   --MAIN-TITLES-TEXT-color: #222; /* Color of titles h2-h3-h4-h5 */
   --MAIN-TITLES-H1-color: #222; /* text color of h1 titles */
-  --MAIN-LINK-color:#f31c1c; /* Color of links */
+  --MAIN-LINK-color:rgb(155, 28, 28); /* Color of links */
   --MAIN-LINK-HOVER-color:#d01616; /* Color of hovered links */
   /* --MAIN-BG-color: rgba( 255, 255, 255, 1 ); /* color of text by default */
 
@@ -15,7 +15,7 @@
   --MENU-HEADER-BG-color:#dc1010; /* Background color of menu header */
   --MENU-HEADER-BORDER-color:#e23131; /*Color of menu header border */
 
-  --MENU-SEARCH-color: #fab0b0; /* Override search field icons color */
+  --MENU-SEARCH-color: #fff; /* Override search field icons color */
   --MENU-SEARCH-BG-color:#b90000; /* Search field background color (by default borders + icons) */
   --MENU-SEARCH-BORDER-color: #ef2020; /* Override search field border color */
 
@@ -37,8 +37,6 @@ div.notices p {
 
 /*
  By default, links are not underlined. This is not recommaned for accessibility.
- So we will underline links, and let the a.highlight animation double underline on hovering.
- Si hugo-theme.css, a.highlight, for more information on about it is done.
  */
 body a.highlight,
 body a.highlight:hover,
@@ -46,4 +44,16 @@ body a.highlight:focus {
   text-decoration: underline;
 }
 
+/* more contrast for the searchbox icons */
+#R-sidebar .searchbox > :first-child,
+#R-sidebar .searchbox > :last-child{
+    opacity: .85;
+}
+
+/* more contrast for the searchbox placeholder */
+.searchbox input::-webkit-input-placeholder,
+.searchbox input::placeholder {
+    opacity: .85;
+}
+
 </style>