css base with rem; used PSD or sketch; rem = size / 10

base.css

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,
main,
menu,
nav,
output,
ruby,
section,
summary,
time,
mark,
audio,
video {
  margin: 0;
  padding: 0;
  border: 0;
  vertical-align: baseline;
}
html {
  font-size: 16px;
  -webkit-tap-highlight-color: transparent;
}
* {
  box-sizing: border-box;
}
/* HTML5 display-role reset for older browsers */
article,
aside,
details,
figcaption,
figure,
footer,
header,
hgroup,
main,
menu,
nav,
section {
  display: block;
}
body {
  color: #000;
  font-size: 1rem;
  line-height: 1.5;
  font-family: "Helvetica Neue", Helvetica, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "\5FAE\8F6F\96C5\9ED1", SimSun, sans-serif;
}
input,
textarea,
keygen,
select,
button {
  outline: none;
  padding: 0;
  margin: 0;
}
ol,
ul {
  list-style: none;
}
blockquote,
q {
  quotes: none;
}
blockquote:before,
blockquote:after,
q:before,
q:after {
  content: '';
  content: none;
}
a {
  text-decoration: none;
}
/* Don't kill focus outline for keyboard users: http://24ways.org/2009/dont-lose-your-focus */
a:hover,
a:active {
  outline: none;
}
table {
  border-collapse: collapse;
  border-spacing: 0;
}
h1,
h2,
h3,
h4,
h5,
h6 {
  font-weight: normal;
}
/*扩展样式*/
.wrapper {
  width: 100%;
}
.clearfix:after,
.clearfix:before {
  display: table;
  content: '';
}
.clearfix:after {
  clear: both;
}
.fl {
  float: left;
}
.fr {
  float: right;
}
.abs {
  position: absolute;
}
.rel {
  position: relative;
}
.one-line {
  white-space: nowrap;
  text-overflow: ellipsis;
  overflow: hidden;
}

rem.js

!(function (doc, win) {
    var docEle = doc.documentElement;
    var evt = 'onorientationchange' in window ? 'orientationchange' : 'resize';
    var fn = function () {
        var width = docEle.clientWidth;
        width && (docEle.style.fontSize = (width / 7.5) + 'px');
    };
    win.addEventListener(evt, fn, false);
    doc.addEventListener('DOMContentLoaded', fn, false);
}(document, window));