css九宫格布局的五种方法

 div{
      width: 300px;
      height: 300px;
  }
    ul{
      padding: 0;
      width: 100%;
      height: 100%;
  }
   li{    
      list-style: none;
      text-align: center;
      line-height: 100px;
      margin: 3px;
      background-color: #243F49;
      color: white;
      border: 1px solid white;
      font-weight: bolder;
  }
<div>
  <ul>
    <li>1</li>
    <li>2</li>
    <li>3</li>
    <li>4</li>
    <li>5</li>
    <li>6</li>
    <li>7</li>
    <li>8</li>
    <li>9</li>
  </ul>
</div>

ul{
      padding: 0;
      width: 100%;
      height: 100%;
      /*设置为grid网格布局*/
      display: grid;
      /*设置三行高度都为100px；*/
      grid-template-rows:100px 100px 100px ;
       /*设置三行宽度都为100px；*/
      grid-template-columns: 100px 100px 100px;
      置网格的行间距、列间距都为3px
      /*grid-gap: 3px;*/
  }

  ul{
      padding: 0;
      width: 100%;
      height: 100%;
      /*设置布局方式为flex布局*/
      display: flex;
      /*换行*/
      flex-wrap: wrap;
  }
  li{
      /*固定设置每个li的宽度和高度*/
      width: 94px;
      height: 94px;
      margin: 3px;
      list-style: none;
      text-align: center;
      line-height: 100px;
      background-color: #243F49;
      color: white;
      border: 1px solid white;
      font-weight: bolder;
  }

  ul{
      padding: 0;
      width: 100%;
      height: 100%;
      /*清除浮动*/
      overflow: hidden;    
  }
  li{
      /*固定设置每个li的宽度和高度*/
      width: 94px;
      height: 94px;
      /*第三种方法：浮动定位进行换行*/
      float: left;
      margin: 3px;
      list-style: none;
      text-align: center;
      line-height: 100px;
      background-color: #243F49;
      color: white;
      font-weight: bolder;
  }

ul{
      padding: 0;
      width: 100%;
      height: 100%;
      /*减少字符间的空白*/
      letter-spacing: -5px;/*这里使用font-size:0;也可*/
   }
   li{
      /*设置每个li的固定宽度和高度*/
      width: 94px;
      height: 94px;
      display: inline-block;
      margin: 3px;
      list-style: none;
      text-align: center;
      line-height: 100px;
      background-color: #243F49;
      color: white;
      font-weight: bolder;
  }

  <style>
ul{
    width: 300px;
    height: 300px;
    /*元素作为块级表格来显示  padding失效*/
    display: table;
    /*设置相邻单元格的边框间距*/
    border-spacing: 5px;
}
li{
    list-style: none;
    text-align: center;
    background-color: #243F49;
    color: white;
    font-weight: bolder;
    /*此元素会作为一个表格行来显示 margin和padding都失效*/
    display: table-row;
}
div{
    line-height: 90px;
    text-align: center;
    /*元素以单元格形式来显示  Margin失效*/
    display: table-cell;
}
 <ul>
    <li>
      <div>1</div>
      <div>2</div>
      <div>3</div>
    </li>
    <li>
      <div>4</div>
      <div>5</div>
      <div>6</div>
    </li>
    <li>
      <div>7</div>
      <div>8</div>
      <div>9</div>
    </li>
  </ul>