.bigrounded {
    -webkit-border-radius: 2em;
    -moz-border-radius: 2em;
    border-radius: 2em;
}
.button {
    display: inline-block;
    outline: none;
    cursor: pointer;
    text-align: center;
    text-decoration: none;
    font: 16px/100% 'Microsoft yahei',Arial,Helvetica,sans-serif;
    padding: .4em 2em .55em;
    text-shadow: 0 1px 1px rgba(0,0,0,.3);
    -webkit-border-radius: .5em;
    -moz-border-radius: .5em;
    border-radius: .5em;
    -webkit-box-shadow: 0 1px 2px rgba(0,0,0,.2);
    -moz-box-shadow: 0 1px 2px rgba(0,0,0,.2);
    box-shadow: 0 1px 2px rgba(0,0,0,.2);
    margin-left:50px;
}

.outer {
    position: relative;
    /*margin: 20px auto;*/
    width: 250px;
    height: 30px;
    line-height: 28px;
    border: 1px solid #ccc;
    background: #ccc9c9;
    font-size: 12px;    
    margin:auto; 
    float:left;
} 

    .outer span, .filter-box, .inner {
        position: absolute;
        top: 0;
        left: 0;
    }

    .outer span {
        display: block;
        padding: 0 0 0 36px;
        width: 100%;
        height: 100%;
        color: #fff;
        text-align: center;
    }

.txtRoll {
    background-image: linear-gradient(to right,black,black, white,black,black, white,black);
    -webkit-text-fill-color: transparent;
    -webkit-background-clip: text;
    -webkit-background-size: 200% 100%;
    animation: bgp 3s infinite linear;
}

@-webkit-keyframes bgp {
    0% {
        background-position: 0 0;
    }

    100% {
        background-position: -100% 0;
    }
}

.filter-box {
    width: 0;
    height: 100%;
    background: green;
    z-index: 9;
}

.outer.act span {
    padding: 0 36px 0 0;
}

.inner {
    width: 36px;
    height: 28px;
    text-align: center;
    background: #fff;
    cursor: pointer;
    font-family: "宋体";
    z-index: 10;
    font-weight: bold;
    color: #929292;
}

.outer.act .inner {
    color: green;
}

.outer.act span {
    z-index: 99;
}