.clearfix::before,
.clearfix::after {
    display: table;
    content: '';
    clear: both;
}

#root,
.main,
body,
html {
    width: 100%;
    height: 100%;
}

/*(1)清除默认样式*/
html,
body,
ul,
li,
ol,
dl,
dd,
dt,
p,
h1,
h2,
h3,
h4,
h5,
h6,
form,
fieldset,
legend,
img,
input {
    margin: 0;
    padding: 0;
}

ul,
li,
ol {
    list-style: none;
}

select,
input {
    vertical-align: middle;
}

textarea {
    resize: none;
}

/*防止拖动*/
img {
    border: 0;
    vertical-align: middle;
}

/*  去掉图片低测默认的3像素空白缝隙，或者用display：block也可以*/
table {
    border-collapse: collapse;
}

/*  如果相邻则共用一个边框*/
a {
    text-decoration: none;
}