水平居中方案

方案一：text-align + inline-block

<div id="parent1"> <div class="child">水平居中div>div>

#parent1{ text-align: center; background:#ddd; margin-bottom:20px;}#parent1 .child{ display: inline-block; background:#666; color:#fff;}

方案二：margin：0 auto

<div id="parent2"> <div class="child">水平居中div>div>

#parent2{ text-align: center; background:#ddd; margin-bottom:20px;}#parent2 .child{ display: table; margin: 0 auto; background:#666; color:#fff;}

方案三：absolute+transform

<div id="parent3"> <div class="child">水平居中div>div>

#parent3{ position: relative; background:#ddd; margin-bottom:20px;}#parent3 .child{ position: absolute; left: 50%; transform: translateX(-50%); background:#666; color:#fff;}

方案四：justify-content

<div id="parent4"> <div class="child">水平居中div>div>

#parent4{ display: flex; justify-content: center; background:#ddd; margin-bottom:20px;}#parent4 .child{ margin:0 auto; background:#666; color:#fff;}

垂直居中方案

方案一：利用 line-height 实现垂直居中

这种方法适用于单行文本垂直居中,如果文本内容太长，出现了换行，换行后的内容会溢出

<div id="example1">    单行文字垂直居中div>

#example1 {    height: 100px;    line-height: 100px;    background: #161616;    color: #fff;    width: 200px;}

方案二利用 display: table 实现垂直居中

<div id="example2">    <div class="inner">块区域垂直居中div>div>

#example2 {    height: 100px;    background: #161616;    color: #fff;    width: 400px;    overflow: hidden;    display: table;   margin-bottom:20px;}#example2 .inner{    display: table-cell;    vertical-align: middle;    height: 50px;    background:#999;}

方案三 margin 填充这种方法需要知道内外容器的大小

<div id="example3">    <div class="inner">块区域垂直居中div>div>

#example3 {    height: 100px;    background: #161616;    color: #fff;    width: 400px;    overflow: hidden;   margin-bottom:20px;}#example3 .inner{    margin-left: auto;    margin-right: auto;    margin-top: calc((100px - 50px)/2);    height: 50px;    background:#999;}

方案四：经典 absolute 布局上下文垂直居中

<div id="example4">    <div class="inner">块区域垂直居中div>div>

#example4 {    width: 400px;    height: 100px;    background: #161616;    color: #fff;    position: relative;  margin-bottom:20px;}#example4 .inner{    height: 50px;    width: 200px;    position: absolute;    left: 50%;    top: 50%;    margin-top: -25px;    margin-left: -100px;    background:#999;}

方案五：absolute+transform

<div id="example5">    <div class="inner">块区域垂直居中div>div>

#example5 {    width: 400px;    height: 100px;    background: #161616;    color: #fff;    position: relative; margin-bottom:20px;}#example5 .inner{    position: absolute;    left: 50%;    top: 50%;    background: #999;    transform: translateX(-50%) translateY(-50%);}

方案六利用margin：auto 居中

<div id="expample6">    <div class="inner">Content herediv>div>

#expample6 {    width: 400px;    height: 100px;    background: #eee;    position: relative;  margin-bottom:20px;}#expample6 .inner {    position: absolute;    top: 0;    bottom: 0;    left: 0;    right: 0;    margin: auto;    height: 50px;    width: 70%;    background: #aaa;    color:#222;}

方案七利用 Flex布局居中

<div id="expample7">    <div class="inner">Content herediv>div>

#expample7 {    width: 400px;    height: 100px;    background: #eee;    display: flex;    justify-content: center;    align-items: center;}#expample7 .inner {    height: 50px;    width: 70%;    background: #aaa;    color:#222;}