作业部落，用来写 Markdown，挺好的，不过样式不太符合我的心意，好在提供自定义功能...

h1 {
    color: Green;
    font-size: 40px;
    font-weight: bold;
}
h2 {
    font-size: 35px;
    width: 834px;
    padding: 8px;
    background-color: LightGreen;
    border-bottom: 1px solid #e2e3e4;
    border-radius: 5px;
}
h3 {
    font-size: 32px;
}
h4 {
    font-size: 28px;
}
h5 {
    font-size: 25px;
}
h6 {
    font-size: 22px;
}
h4, h5, h6 {
    margin: 20px 0;
}
kbd {
    display: inline-block;
    margin: 0 .1em;
    padding: .1em .6em;
    font-family: Arial,"Helvetica Neue",Helvetica,sans-serif;
    font-size: 11px;
    line-height: 1.4;
    color: #242729;
    text-shadow: 0 1px 0 #FFF;
    background-color: #e1e3e5;
    border: 1px solid #adb3b9;
    border-radius: 3px;
    box-shadow: 0 1px 0 rgba(12,13,14,0.2),0 0 0 2px #FFF inset;
    white-space: nowrap;
}
h1 code, h2 code, h3 code, h4 code, h5 code, h6 code {
    font-size: inherit;
}