纯CSS画的基本图形（矩形、圆形、三角形、多边形、爱心、八卦等）

这些代码的来源是css-tricks。原文链接： http://www.itivy.com/ivy/archive/2012/1/16/css-shape.html

1、圆形

CSS代码如下：宽高一样，border-radius设为宽高的一半

#circle {width: 100px;height: 100px;background: red;-moz-border-radius: 50px;-webkit-border-radius: 50px;border-radius: 50px;
}

2、椭圆

CSS代码如下：border-radius:水平半径/垂直半径

#oval {width: 200px;height: 100px;background: red;-moz-border-radius: 100px / 50px;-webkit-border-radius: 100px / 50px;border-radius: 100px / 50px;
}

3、等边三角

上三角CSS代码如下：设置border-bottom宽度实线颜色，左右border左右宽度为一半，实线透明。下三角、左三角、右三角可举一反三实现。

#triangle-up {width: 0;height: 0;border-left: 50px solid transparent;border-right: 50px solid transparent;border-bottom: 100px solid red;
}

4、直角三角

左上三角CSS代码如下：border-top设置宽度实线颜色，border-right等宽实线透明。右上三角、左下三角、右下三角可举一反三实现。

#triangle-topleft {width: 0;height: 0;border-top: 100px solid red; border-right: 100px solid transparent;          
}

5、平行四边形

CSS代码如下：transform: skew，倾斜角度即为四边形锐角的余角

#parallelogram {width: 150px;height: 100px;margin-left:20px;-webkit-transform: skew(20deg);-moz-transform: skew(20deg);-o-transform: skew(20deg);background: red;
}

6、梯形

CSS代码如下：上底长为width的值，下底长为width+border-left+border-right之和，高为border-bottom

#trapezoid {border-bottom: 100px solid red;border-left: 50px solid transparent;border-right: 50px solid transparent;height: 0;width: 100px;
}

7、五边形（五角大楼）

CSS代码如下：

#pentagon {position: relative;width: 54px;border-width: 50px 18px 0;border-style: solid;border-color: red transparent;
}
#pentagon:before {content: "";position: absolute;height: 0;width: 0;top: -85px;left: -18px;border-width: 0 45px 35px;border-style: solid;border-color: transparent transparent red;
}

8、六边形

CSS代码如下：

#hexagon {width: 100px;height: 55px;background: red;position: relative;
}
#hexagon:before {content: "";position: absolute;top: -25px; left: 0;width: 0;height: 0;border-left: 50px solid transparent;border-right: 50px solid transparent;border-bottom: 25px solid red;
}
#hexagon:after {content: "";position: absolute;bottom: -25px; left: 0;width: 0;height: 0;border-left: 50px solid transparent;border-right: 50px solid transparent;border-top: 25px solid red;
}

9、八边形

CSS代码如下：

#octagon {width: 100px;height: 100px;background: red;position: relative;
}#octagon:before {content: "";position: absolute;top: 0;left: 0;    border-bottom: 29px solid red;border-left: 29px solid #eee;border-right: 29px solid #eee;width: 42px;height: 0;
}#octagon:after {content: "";position: absolute;bottom: 0;left: 0;    border-top: 29px solid red;border-left: 29px solid #eee;border-right: 29px solid #eee;width: 42px;height: 0;
}

10、五角星

CSS代码如下：

#star-five {margin: 50px 0;position: relative;display: block;color: red;width: 0px;height: 0px;border-right:  100px solid transparent;border-bottom: 70px  solid red;border-left:   100px solid transparent;-moz-transform:    rotate(35deg);-webkit-transform: rotate(35deg);-ms-transform:     rotate(35deg);-o-transform:      rotate(35deg);
}
#star-five:before {border-bottom: 80px solid red;border-left: 30px solid transparent;border-right: 30px solid transparent;position: absolute;height: 0;width: 0;top: -45px;left: -65px;display: block;content: '';-webkit-transform: rotate(-35deg);-moz-transform:    rotate(-35deg);-ms-transform:     rotate(-35deg);-o-transform:      rotate(-35deg);}
#star-five:after {position: absolute;display: block;color: red;top: 3px;left: -105px;width: 0px;height: 0px;border-right: 100px solid transparent;border-bottom: 70px solid red;border-left: 100px solid transparent;-webkit-transform: rotate(-70deg);-moz-transform:    rotate(-70deg);-ms-transform:     rotate(-70deg);-o-transform:      rotate(-70deg);content: '';
}

11、六角星

CSS代码如下：一个上三角和一个下三角拼合而成

#star-six {width: 0;height: 0;border-left: 50px solid transparent;border-right: 50px solid transparent;border-bottom: 100px solid red;position: relative;
}
#star-six:after {width: 0;height: 0;border-left: 50px solid transparent;border-right: 50px solid transparent;border-top: 100px solid red;position: absolute;content: "";top: 30px;left: -50px;
}

12、八角星

CSS代码如下：

#burst-8 {background: red;width: 80px;height: 80px;position: relative;text-align: center;-webkit-transform: rotate(20deg);-moz-transform: rotate(20deg);-ms-transform: rotate(20deg);-o-transform: rotate(20eg);transform: rotate(20deg);
}
#burst-8:before {content: "";position: absolute;top: 0;left: 0;height: 80px;width: 80px;background: red;-webkit-transform: rotate(135deg);-moz-transform: rotate(135deg);-ms-transform: rotate(135deg);-o-transform: rotate(135deg);transform: rotate(135deg);
}

13、十二角星

CSS代码如下：

#burst-12 {background: red;width: 80px;height: 80px;position: relative;text-align: center;
}
#burst-12:before, #burst-12:after {content: "";position: absolute;top: 0;left: 0;height: 80px;width: 80px;background: red;
}
#burst-12:before {-webkit-transform: rotate(30deg);-moz-transform: rotate(30deg);-ms-transform: rotate(30deg);-o-transform: rotate(30deg);transform: rotate(30deg);
}
#burst-12:after {-webkit-transform: rotate(60deg);-moz-transform: rotate(60deg);-ms-transform: rotate(60deg);-o-transform: rotate(60deg);transform: rotate(60deg);
}

14、爱心

CSS代码如下：

#heart {position: relative;width: 100px;height: 90px;
}
#heart:before,
#heart:after {position: absolute;content: "";left: 50px;top: 0;width: 50px;height: 80px;background: red;-moz-border-radius: 50px 50px 0 0;border-radius: 50px 50px 0 0;-webkit-transform: rotate(-45deg);-moz-transform: rotate(-45deg);-ms-transform: rotate(-45deg);-o-transform: rotate(-45deg);transform: rotate(-45deg);-webkit-transform-origin: 0 100%;-moz-transform-origin: 0 100%;-ms-transform-origin: 0 100%;-o-transform-origin: 0 100%;transform-origin: 0 100%;
}
#heart:after {left: 0;-webkit-transform: rotate(45deg);-moz-transform: rotate(45deg);-ms-transform: rotate(45deg);-o-transform: rotate(45deg);transform: rotate(45deg);-webkit-transform-origin: 100% 100%;-moz-transform-origin: 100% 100%;-ms-transform-origin: 100% 100%;-o-transform-origin: 100% 100%;transform-origin :100% 100%;
}

15、无穷大符号

CSS代码如下：

#infinity {position: relative;width: 212px;height: 100px;
}#infinity:before,
#infinity:after {content: "";position: absolute;top: 0;left: 0;width: 60px;height: 60px;    border: 20px solid red;-moz-border-radius: 50px 50px 0 50px;border-radius: 50px 50px 0 50px;-webkit-transform: rotate(-45deg);-moz-transform: rotate(-45deg);-ms-transform: rotate(-45deg);-o-transform: rotate(-45deg);transform: rotate(-45deg);
}#infinity:after {left: auto;right: 0;-moz-border-radius: 50px 50px 50px 0;border-radius: 50px 50px 50px 0;-webkit-transform: rotate(45deg);-moz-transform: rotate(45deg);-ms-transform: rotate(45deg);-o-transform: rotate(45deg);transform: rotate(45deg);
}

16、鸡蛋

CSS代码如下：

#egg {display:block;width: 126px; height: 180px;background-color: red;-webkit-border-radius: 63px 63px 63px 63px / 108px 108px 72px 72px;border-radius:        50%   50%  50%  50%  / 60%   60%   40%  40%;
}

17、食豆人（Pac-Man）

CSS代码如下：

#pacman {width: 0px;height: 0px;border-right: 60px solid transparent;border-top: 60px solid red;border-left: 60px solid red;border-bottom: 60px solid red;border-top-left-radius: 60px;border-top-right-radius: 60px;border-bottom-left-radius: 60px;border-bottom-right-radius: 60px;
}

18、提示对话框

CSS代码如下：

#talkbubble {width: 120px; height: 80px; background: red;position: relative;-moz-border-radius:    10px; -webkit-border-radius: 10px; border-radius:         10px;
}
#talkbubble:before {content:"";position: absolute;right: 100%;top: 26px;width: 0;height: 0;border-top: 13px solid transparent;border-right: 26px solid red;border-bottom: 13px solid transparent;
}

19、钻石

CSS代码如下：

#cut-diamond {border-style: solid;border-color: transparent transparent red transparent;border-width: 0 25px 25px 25px;height: 0;width: 50px;position: relative;margin: 20px 0 50px 0;
}
#cut-diamond:after {content: "";position: absolute;top: 25px;left: -25px;width: 0;height: 0;border-style: solid;border-color: red transparent transparent transparent;border-width: 70px 50px 0 50px;
}

20、阴阳八卦

CSS代码如下：

#yin-yang {width: 96px;height: 48px;background: #eee;border-color: red;border-style: solid;border-width: 2px 2px 50px 2px;border-radius: 100%;position: relative;
}#yin-yang:before {content: "";position: absolute;top: 50%;left: 0;background: #eee;border: 18px solid red;border-radius: 100%;width: 12px;height: 12px;
}#yin-yang:after {content: "";position: absolute;top: 50%;left: 50%;background: red;border: 18px solid #eee;border-radius:100%;width: 12px;height: 12px;
}