a ( position: relative; padding-bottom: 2px; text-decoration: none; ) a:hover::after ( content: ""; position: absolute; bottom: 2px; left: 0; height: 1px; width: 100%; background: #444; background: linear-gradient(left, transparent 0%,#444 50%,transparent 100%); )CodePen'de Chris Coyier (@chriscoyier) tarafından hazırlanan Kalem Degrade Alt Çizgilerine bakın.