ul.semaforo {
    width: 60px;
    margin: 40px auto;
    padding: 0;
    margin-top: 10px;
    list-style-type: none;
    vertical-align:top;
    }
    ul.semaforo li {
    display: block;
    float: left;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: lightgrey;
    vertical-align:top;
    }
    .verde li:nth-of-type(1) {
    border-color: limegreen;
    background-color: limegreen;
    background: radial-gradient(center, ellipse cover, #00ff00 1%, #32cd32 100%);
    }
    .amarillo li:nth-of-type(2) {
    border-color: orange;
    background-color: orange;
    background: radial-gradient(center, ellipse cover, #ffd700 1%, #ff8c00 100%);
    }
    .rojo li:nth-of-type(3) {
    border-color: red;
    background-color: red;
    background: radial-gradient(center, ellipse cover, #ff0000 1%,#cc0000 100%);
    }
    
    
    
    /* Semáforo realista CSS */
    /*
    ul.semaforo {
    float:left;
    position: relative;
    width: 14px;
    margin: 20px;
    padding: 1px;
    list-style-type: none;
    border: 5px double grey;
    background: black;
    background: linear-gradient( -90deg, #45484d 10%, #000000 100%);
    border-radius: 20%;
    box-shadow: 0px 0px 0 2px rgba(0,0,0,.8);
    }
    ul.semaforo li {
    position:relative;
    width: 15px;
    height: 15px;
    border-radius: 50%;
    background: lightgrey;
    margin: 5px 0;
    background: linear-gradient(top, rgba(187,187,187,1) 0%,rgba(119,119,119,1) 99%);
    box-shadow: inset 0 -5px 15px rgba(255,255,,0.4),
    inset -2px -1px 40px rgba(0,0,0,0.4),
    0 0 1px #000;
    }
    ul.semaforo li:after {
    content: "";
    width: 1px;
    height: 1px;
    position: absolute;
    left: 20px;
    top: 10px;
    box-shadow: 0px 0 20px 15px rgba(20,20,20,.1);
    border-radius: 30px / 15px;
    }
    .rojo li:nth-of-type(1) {
    background: #cc0000;
    background: radial-gradient(center, ellipse cover, #ff0000 1%, #cc0000 100%);
    }
    .naranja li:nth-of-type(2) {
    background: #FF9326;
    }
    .verde li:nth-of-type(3) {
    background: #00ff00;
    }
    
    */