cssreset

html, body, div, span, applet, object, iframe,
h1, h2, h3, h4, h5, h6, p, blockquote, pre,
a, abbr, acronym, address, big, cite, code,
del, dfn, em, img, ins, kbd, q, s, samp,
small, strike, strong, sub, sup, tt, var,
b, u, i, center,
dl, dt, dd, ol, ul, li,
fieldset, form, label, legend,
table, caption, tbody, tfoot, thead, tr, th, td,
article, aside, canvas, details, embed,
figure, figcaption, footer, header, hgroup,
menu, nav, output, ruby, section, summary,
time, mark, audio, video {
    margin: 0;
    padding: 0;
    border: 0;
    font-size: 100%;
    font: inherit;
    vertical-align: baseline;
}

/* HTML5 display-role reset for older browsers */
article, aside, details, figcaption, figure,
footer, header, hgroup, menu, nav, section {
    display: block;
}

body {
    line-height: 1;
}

ol, ul {
    list-style: none;
}

blockquote, q {
    quotes: none;
}

blockquote:before, blockquote:after,
q:before, q:after {
    content: '';
    content: none;
}

table {
    border-collapse: collapse;
    border-spacing: 0;
}
html {
    font-size: 62.5%;
    color: #222;
}

::selection {
    background-color: #b3d4fc;
    text-shadow: none;
}

ul {
    margin: 0;
    padding: 0;
}

li {
    list-style: none;
}
.clearfix:before,
.clearfix:after {
    content: " ";
    display: table;
}

.clearfix:after {
    clear: both;
}
/* ===============
   自定义页面样式
   =============== */
body {
    font:1.2rem "simhei",Arial,Helvetica,sans-serif;
    line-height: 1.5;
    background-color: #f7f7f7;
}

a {
    color: #666;
    text-decoration: none;
}

a:hover, a:active {
    color: #0ae;
    text-decoration: underline;

}

font-size 1rem=10px

width height padding margin 1rem=12px

border使用px为单位