Fix menu hover color and img margin

On administration guide, the top menu items should be white on dark when
hovering them.

On documentation front page, illustrations in cards should be centered.

Author: nterray

README.md

@@ -41,7 +41,7 @@ To build the documentation in watch mode:
     nix-shell
     npm ci
     npm run build
-    make SPHINXOPTS="-D html_theme=tuleap_online_doc" watch-html
+    make watch-html-online-docs
 
 > A web-server will start, the modifies pages will be rebuilt and reloaded automatically each time you save your work.
 

languages/en/_themes/tuleap_online_doc/style/backbone/_card.scss

@@ -31,6 +31,10 @@
     height: 175px;
 }
 
+.doc-content .card-illustration > img {
+    margin: 0;
+}
+
 .card-title {
     flex: 0 0 auto;
     margin: 0;

languages/en/_themes/tuleap_online_doc/style/backbone/_header.scss

@@ -156,6 +156,10 @@ body:not(.pinned) {
             .header-menu-item {
                 color: $hexa;
 
+                &:hover {
+                    color: variables.$white;
+                }
+
                 &.active {
                     background: $hexa;
                     color: variables.$white;