Changing the appearance of the button backgrounds

You can change the colours for the buttons on the top right of the site, the arrow on the base map picker and the Close buttons on dialogs.

This is controlled by the section ui-widget-header .ui-state-default.

.ui-widget-header .ui-state-default {
	border: 1px solid #0065a2;
	/* Original solid blue button background, created by theme roller */
	/* background: #0065a2 url("images/ui-bg_flat_0_0065a2_40x100.png") 50% 50% repeat-x; */
       /* Transparent background added to buttons as RGB because the default blue, 
	defined as a Hex colour, does not support transparency.*/
	background: rgba(0,101,162, 0.60);
	color: #000000;

Change the colour and transparency of the buttons by editing background: rgba(0,101,162, 0); to the RGBA code that will give you the colour/transparency you require.