1.需求有这么个东西，个人不习惯背景图片来解决，开始了css尝试。
1 <!DOCTYPE html> 2 <html> 3 <head> 4 <meta charset="UTF-8"> 5 <title>边框渐变的拱形</title> 6 <style> 7 8 .circle{ 9 width: 200px; 10 /*height: 200px;*/ 11 line-height: 100px; 12 text-align: center; 13 margin: 100px; 14 /*background-color: red;*/ 15 } 16 .semi-circle { 17 border-radius: 200px 200px 0 0 ; 18 height: 100px; 19 border: 20px solid red; 20 border-bottom: 0; 21 /*border-image: -moz-linear-gradient(green,blue); 22 border-image: -webkit-linear-gradient(green,blue); 23 border-image: linear-gradient(to right,green,blue) 30 30;*/ 24 } 25 26 </style> 27 </head> 28 <body> 29 <div class="circle semi-circle"></div> 30 31 </body> 32 </html>
2.基于上图 尝试用背景渐变来解决，so border-image上了，（不要问为啥不用border-color），但是圆角没有了，因为他们都是对border的设置。后从网上看到有伪类去做的背景渐变的按钮。
1 <!DOCTYPE html> 2 <html> 3 <head> 4 <meta charset="UTF-8"> 5 <title>边框渐变的拱形</title> 6 <style> 7 8 .border{ 9 position: relative; 10 border: 4px solid transparent; 11 border-radius: 16px; 12 background: linear-gradient(orange, violet); 13 background-clip: padding-box; 14 padding: 10px; 15 /* just to show box-shadow still works fine */ 16 box-shadow: 0 3px 9px black, inset 0 0 9px white; 17 } 18 .border::after{ 19 position: absolute; 20 top: -4px; bottom: -4px; 21 left: -4px; right: -4px; 22 background: linear-gradient(red, blue); 23 content: ''; 24 z-index: -1; 25 border-radius: 16px; 26 } 27 28 </style> 29 </head> 30 <body> 31 32 <div class="border"></div> 33 34 </body> 35 </html>
效果如下：
3.然后开始改造
1 <!DOCTYPE html> 2 <html> 3 <head> 4 <meta charset="UTF-8"> 5 <title>边框渐变的拱形</title> 6 <style> 7 8 .border1{ 9 width: 200px; 10 height: 200px; 11 margin:100px auto; 12 13 position: relative; 14 border: 1px solid transparent; 15 border-radius: 200px; 16 background: white; 17 background-clip: padding-box; 18 padding: 10px; 19 } 20 .border1::after{ 21 22 position: absolute; 23 top: -40px; 24 bottom: -40px; 25 left: -40px; 26 right: -40px; 27 background: linear-gradient(to right,red, blue); 28 content: ''; 29 z-index: -1; 30 border-radius: 200px; 31 } 32 33 </style> 34 </head> 35 <body> 36 37 <div class="border1"></div> 38 39 </body> 40 </html>
4.再次改造
1 <!DOCTYPE html> 2 <html> 3 <head> 4 <meta charset="UTF-8"> 5 <title>边框渐变的拱形</title> 6 <style> 7 8 .border2{ 9 width: 200px; 10 height: 100px; 11 margin:100px auto; 12 13 position: relative; 14 border: 1px solid transparent; 15 border-bottom: 0; 16 border-radius: 200px 200px 0 0; 17 background: white; 18 background-clip: padding-box; 19 padding: 10px; 20 } 21 .border2::after{ 22 23 position: absolute; 24 top: -40px; 25 bottom: 0px; 26 left: -40px; 27 right: -40px; 28 background: linear-gradient(to right,red, blue); 29 content: ''; 30 z-index: -1; 31 border-radius: 200px 200px 0 0; 32 } 33 </style> 34 </head> 35 <body> 36 37 <div class="border2"></div> 38 </body> 39 </html>
最终达到想要的效果。