CSS entry notes twelve: rounded borders and box shadows

Rounded border :

	border-radius: 像素值/百分比;

Application of rounded border :
1. Making a round box: Set the radius of the rounded border in a square box to be one-half of the length of the square.

2. Make a rounded rectangle: the radius of the rounded border is half the height of the box

3. The rounded border can be followed by 1 to 4 values ​​to set a different rounded border for each corner

Box shadow

   box-shadow:像素值（水平阴影） 像素（垂直阴影） 像素值（值越大，阴影越模糊） 像素值（阴影大小）
   rgb(阴影颜色) ；

Text shadow : text-shadow;