Use css to create a custom arrow shape [duplicate]

Answer 1

This is pretty simple. You just need to set the color of top/bottom borders of the ::before pseudo-element to the background color and change the color of left border to transparent.

Then you could use margins/offsets to position the pseudo-element properly.

body { background-color: gold; }

#flag { 
  width: 400px; height: 80px; background: #231f20; position: relative;
  margin-left: 35px;
  color: white;
  line-height: 80px;
  text-align: center;
}

#flag:before { 
  content: ""; 
  position: absolute; 
  top: 0; 
  left: -35px;
  width: 0; 
  height: 0; 
  border-top: 40px solid #231f20; 
  border-bottom: 40px solid #231f20; 
  border-left: 35px solid transparent;

}

#flag:after { 
  content: ""; 
  position: absolute; 
  left: 400px; 
  bottom: 0; 
  width: 0; 
  height: 0; 
  border-top: 40px solid transparent;

  border-bottom: 40px solid transparent;

  border-left: 45px solid #231f20;
}

This is it!