fix link styles in main.css file.

Default links were changed in previous commit and had a knock-on effect to some
stylised links.

static/css/main.css

@@ -179,11 +179,12 @@ input[type=password] {
     white-space: break-spaces !important;
 }
 
-.be-gui-link,
-.be-gui-button,
+.be-gui-link:link,
+.be-gui-button:link,
 .be-gui-link-no-text,
 .be-gui-button-no-text {
     background: #905da1;
+    color: white;
 }
 
 .be-gui-link-no-text {
@@ -240,6 +241,14 @@ input[type=password] {
 .be-gui-link-no-text:hover,
 .be-gui-button-no-text:hover {
     background: #473951;
+    text-decoration: none;
+    color: white;
+}
+
+.be-gui-link:visited,
+.be-gui-button:visited {
+    /* background: #905da1; */
+    color: white;
 }
 
 .be-gui-link img,