Css实现圆环

.circle { width: 15px; height: 15px; border: 4px solid green; border-radius: 50%; position: relative; background-color: white; }

.circle::before { content: ""; position: absolute; top: 3px; left: 3px; right: 3px; bottom: 3px; background-color: green; border-radius: 50%; }