CSS矩形、三角形等

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;
}

来源：https://www.cnblogs.com/0828-li/p/10362037.html