5.css triangle approach

                    

As shown above, the small triangle like this could be written by the following code:

• 

  .box1 {
              width: 0;
              height: 0;
              /* border: 10px solid pink; */
              border-top: 10px solid pink;
              border-right: 10px solid red;
              border-bottom: 10px solid blue;
              border-left: 10px solid green;
          }

  View Code

  Such code patterns appearing below

          

• If the four sides of the transparent color into three sides, triangular pattern, the code appears as follows:

.box2 {
            width: 0;
            height: 0;
            border: 50px solid transparent;
            border-left-color: pink;
            margin: 100px auto;
        }

View Code

• Jingdong style production, the following code:

.jd {
            position: relative;
            width: 200px;
            height: 200px;
            background-color: pink;
        }

        .jd span {
            position: absolute;
            top: -10px;
            right: 0px;
            width: 0;
            height: 0;
            border: 5px solid transparent;
            border-bottom-color: red;
        }


      <div class="jd">
        <span></span>
    </div>

View Code