Makes the WordPress admin bar small and unobtrusive up in the corner of the screen.

wp-small-admin-bar.php

/*
 * Mini Admin Bar
 * Modified from plugin URI: http://www.netyou.co.il/
 * Description: Makes the admin bar a small button on the left and expands on hover.
*/

add_action('get_header', 'my_filter_head');
function my_filter_head() { remove_action('wp_head', '_admin_bar_bump_cb'); }

function my_admin_css() {
        if ( is_user_logged_in() && get_current_user_id() == 1) {
        ?>
        <style type="text/css">
            #wpadminbar:not(:hover) {
                position: fixed;
                left: 1px;
                top: 1px;
                width: 20px;
                height: 20px;
                min-width: 20px;
                overflow: hidden;
                opacity: .15;
                border-radius: 50%;
            }
            #wpadminbar:after {
                content: "";
                position: absolute;
                background: #008000;
                top: 0;
                bottom: -100px !important;
                right: 0;
                left: 0;
                /*IE hack*/
                background-color: #fff;
                filter:alpha(opacity=0);
                opacity: 0;
            }
            #wpadminbar:not(:hover) #wp-admin-bar-wp-logo {
                margin-left: -8px !important;
                margin-top: -6px !important;
            }
        </style>
        <?php }
}
add_action('wp_head', 'my_admin_css');