body {
    font-family: SimHei;
    background-image: url('/imgs/retina_dust.webp');
    color: #333;
}
header {
    text-align: center;
    margin: 50px;
    color: #333;
}
article {
    max-width: 660px;
    min-width: 460px;
    margin: 0 auto;
}
table {
    width: 100%;
}
td {
    line-height: 30px;

}
.link {
    margin-left: 10px;
    text-decoration: none;
    color: #444;
    display: inline-block;
    vertical-align: middle;
    -webkit-transform: translateZ(0);
    transform: translateZ(0);
    box-shadow: 0 0 2px rgba(0, 0, 0, 0);
    -webkit-backface-visibility: hidden;
    backface-visibility: hidden;
    -moz-osx-font-smoothing: grayscale;
    position: relative;
    overflow: hidden;
    transition: all 0.3s;
}
.link:before {
    content: "";
    position: absolute;
    z-index: -1;
    left: 50%;
    right: 50%;
    bottom: 0;
    background: #9c9;
    height: 2px;
    color: #9c9;
    -webkit-transition-property: left, right;
    transition-property: left, right;
    -webkit-transition-duration: 0.3s;
    transition-duration: 0.3s;
    -webkit-transition-timing-function: ease-out;
    transition-timing-function: ease-out;
}
.link:hover:before,
.link:focus:before,
.link:active:before {
    left: 0;
    right: 0;
}
.link:hover {
    color: green;
}
footer {
    margin-top: 60px;
    text-align: center;
}