Draw triangle in corner of div

Question

I\'d like to draw some kind of triangle in the corner of a div. Because I don\'t want to use "px" I\'d like to achieve the same result also with percentage values.

Answer 1

You can use position: absolute on triangle element and set top and right properties to 0.

.container {
  position: absolute;
  top: 5%;
  left: 5%;
  width: 60%;
  height: 30%;
  background: black;
  color: white;
  border-radius: 12px;
  overflow: hidden;
}

.triangle {
  width: 0;
  height: 0;
  border-style: solid;
  border-width: 0 30px 30px 0;
  border-color: transparent #608A32 transparent transparent;
  right: 0;
  top: 0;
  position: absolute;
}

You can also just use pseudo-element with absolute position for triangle.

.container {
  position: relative;
  width: 300px;
  height: 70px;
  background: black;
  border-radius: 12px;
  overflow: hidden;
}

.container:after {
  content: '';
  width: 0;
  height: 0;
  border-style: solid;
  border-width: 0 30px 30px 0;
  border-color: transparent #608A32 transparent transparent;
  right: 0;
  top: 0;
  position: absolute;
}

Below is another example with triangles in all corners.

.all_triangles_container {
  position: relative;
  width: 300px;
  height: 70px;
  background: black;
  overflow: hidden;
}

.triangle {
  width: 0;
  height: 0;
  border-style: solid;
  position: absolute;
}

.triangle_tl {
  border-width: 0 0 30px 30px;
  border-color: transparent transparent transparent green;
  left: 0;
  top: 0;
}

.triangle_tr {
  border-width: 0 30px 30px 0;
  border-color: transparent red transparent transparent;
  right: 0;
  top: 0;
}

.triangle_br {
  border-width: 30px 30px 0 0;
  border-color: transparent yellow transparent transparent;
  right: 0;
  bottom: 0;
}

.triangle_bl {
  border-width: 0 30px 30px 0px;
  border-color: transparent transparent purple transparent;
  left: 0;
  bottom: 0;
}