MediaWiki:Common.css

/* CSS placed here will be applied to all skins */
.tooltip {
    position: relative
}

.tooltiptext {
    position: absolute;
    display: block;
    z-index: 2;
    width: 250px;
    padding: 10px;
    visibility: hidden;
    opacity: 0;
    white-space: normal;
    text-align: left;
    transition: all 0.2s;
    border: 1px solid #aaa;
    background-color: #aaff00
}

.tooltip:hover>.tooltiptext {
    visibility: visible;
    opacity: 1
}

.a {
    color: #aaff00;
}

.a:visited {
    color: #afe60b;
}

.vector-menu-tabs-legacy li {
    background-image: linear-gradient(to top, #aaff00 0, #aaff00 1px, #ffffff 100%);
}