<html>
    <head>
        <title>交通信号灯</title>
        <style>
            .box {
            width: 250px;
            height: 52px;
            padding: 15px 30px;
            border: 2px solid #ccc;
            border-radius: 16px;
            margin: 0 auto;
            background-color: #333;
            }

            .box .second {
            width: 60px;
            color: #666;
            font-size: 280%;
            line-height: 50px;
            padding-left: 6px;
            margin-left: 5px;
            border: 1px solid #fff
            }

            .box div {
            margin-left: 5px;
            float: left;
            width: 50px;
            height: 50px;
            border-radius: 50px;
            border: 1px solid #666;
            }

            .box .second {
            border: 0;
            color: #eee;
            }

            .off {
            background-color: #eee;
            }

            .red {
            background-color: red;
            }

            .yellow {
            background-color: yellow;
            }

            .green {
            background-color: #26ff00;
            }
        </style>
    </head>
    <body>
        <div class="box">
            <div id="red">

            </div>

            <div id="yellow">
            </div>

            <div  id="green">
            </div>

            <div class="second" id="second">
            </div>
        </div>
    </body>
</html>