移动端弹性盒

body {
    background: #F7F7F7;
    display: box;
    display: -webkit-box;
    -webkit-box-orient: vertical;
}

section {
    display: block;
    -webkit-box-flex: 1;
    box-flex: 1;
     100%;
    overflow: auto;
    position: relative;
}