* {
    margin: 0;
    padding: 0;
}

body {
    font-size: 12px;
    text-align: center;
    font-family: Microsoft YaHei, sans-serif;
    padding: 50px 0;
}
ul, ol {
    list-style-type: none;
}
img {
    border: none;
    max-width: 100%;
}
a {
    text-decoration: none;
}

.text-center {
    text-align: center;
}
.text-left {
    text-align: left;
}
.text-right {
    text-align: right;
}
.clear {
    clear: both;
}

.content {
    padding-top: 90px;
    line-height: 200%;
    text-align: center;
}

.top {
    background: url(images/download-top.png) bottom repeat-x;
    background-size: cover;
    height: 50px;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
}

.bottom {
    background: url(images/download-bottom.png) repeat-x;
    background-size: cover;
    height: 50px;
    position: fixed;
    bottom: 0;
    left: 0;
    width: 100%;
}

.button {
    background: #257bb3;
    color: #fff;
    line-height: 40px;
    height: 40px;
    width: 160px;
    display: block;
    margin: 0 auto;
    font-size: 15px;
    border-radius: 3px;
}
.button img {
    vertical-align: middle;
}

.tips {
    position: fixed;
    height: 100%;
    width: 100%;
    z-index: 1000;
    background: #000;
    opacity: 0.85;
    top: 0;
    left: 0;
    display: none;
}