body {
    font-family: "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Heiti SC", "Microsoft YaHei", "WenQuanYi Micro Hei", sans-serif;
}

pre * {
    font-family: "Menlo", "Monaco", "Consolas", "Courier New", "Microsoft YaHei", "WenQuanYi Micro Hei", monospace;
}

pre {
    overflow-x: auto;
}

html,
body {
    height: 100%;
    margin: 0;
    padding: 0;
    display: flex;
    flex-direction: column;
}

body{
    padding: 0 3px;
}

main {
    flex: 1;
}

main {
    margin: 0 auto;
    max-width: 100vw;
    min-width: 100%;
}

@media screen and (min-width: 640px) {
    main {
        min-width: 640px;
        max-width: 640px;
    }
}

footer {
    /* 显示在最底部，如果内容不够，显示在屏幕最下方 */
    color: #888;
    font-size: 0.75em;
    text-align: center;
    margin: 10px 0px;
}

footer a {
    color: #888;
}

h1,
h2,
h3,
h4,
h5,
h6 {
    margin: 0;
    padding: 0;
}

h1 {
    padding: 8px;
    padding-bottom: 21px;
    text-align: center;
}

h2 {
    padding-bottom: 11px;
    padding-top: 11px;
    border-bottom: 1px solid #ccc;
}

h3 {
    padding-bottom: 11px;
    padding-top: 11px;
}

img{
    max-width: 100%;
}

p{
    margin: 0.5em 0;
    padding: 0;
}

ul, ol {
    margin: 0;
}

li {
    margin: 5px 0;
}