利用background-image里的liner-gradient属性可以实现一些简单的css网格背景，能自适应背景，挺实用的，下面就简单的介绍两款网格背景
1.桌布花纹
红.png
代码块
height:300px;
width:300px;
background:white;
background-image:linear-gradient(90deg,rgba(200,0,0,.5) 50%,transparent 0),
linear-gradient(rgba(200,0,0,.5) 50%,transparent 0);
background-size:30px 30px;
2.蓝图网格
蓝色.png
代码块
height: 300px;
width: 300px;
background:#58a;
background-image: linear-gradient(white 2px,transparent 0),
linear-gradient(90deg, white 2px,transparent 0),
linear-gradient(hsla(0,0%,100%,.3) 1px,transparent 0),
linear-gradient(90deg,hsla(0,0%,100%,.3) 1px,transparent 0);
background-size:75px 75px,75px 75px,15px 15px,15px 15px;
