html 构造
<body>
<div class="wrapper">
<div class="left"></div>
<div class="right"></div>
</div>
</body>办法一：flex 布局
.wrapper{display:flex;}
.left{
width:200px;
height:400px;
background:black;
}
.right{
flex:1;
height:400px;
background:red;
}办法二：浮动
.left{
float:left;
width:200px;
height:400px;
background:black;
}
.right{
background:red;
height:400px;
}办法三：BFC
.left{
width:200px;
height:400px;
float:left;
background:black;
}
.right{
overflow:hidden;
height:400px;
background:red;
}办法四：position 相对定位
.wrapper{position:relative;}
.left{
width:200px;
height:400px;
background:black;
}
.right{
position:absolute;
top:0;
left:200px;
right:0;
bottom:0;
background:red;
}办法五：table 布局
.wrapper{
display:table;
width:100%;
}
.left,.right{
display:table-cell;
height:400px
}
.left{background:black;}
.right{background:red;}办法六：grid 布局
.wrapper{
display:grid;
width:100%;
height:400px;
grid-template-columns:200px auto;
}
.left{background:black;}
.right{background:red;}