css - Three colors angled background color

Question

How could I achieve a background that looked similar to this image:

Only 3 colors, angled from the top corner out like a sunray.

Maybe sticking with a simple PNG or SVG background image would be a better approach.

Answer 1

The effect can be achieved with CSS using pseudo-elements and transforms and the below is a sample snippet. But I don't think using CSS is the correct option for this. It would be better to use a PNG image.

The snippet uses a couple of pseudo-elements with different background colors skewed at required angles to produce the three-color effect.

.bg {
  position: relative;
  height: 200px;
  width: 400px;
  padding: 4px;
  background: orange;
  overflow: hidden;
}
.bg:after,
.bg:before {
  position: absolute;
  content: '';
  left: 0px;
  height: 100%;
  width: 100%;
  transform-origin: right top;
}
.bg:before {
  top: 0px;
  background: red;
  transform: skewY(-45deg);
}
.bg:after {
  top: -100%;
  background: yellow;
  transform: skewY(-15deg);
}
span {
  position: relative;
  z-index: 2;
}

/* Just for demo */
.bg:hover {
  height: 200px;
  width: 500px;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/prefixfree/1.0.7/prefixfree.min.js"></script>
<div class="bg">
  <span>Some content inside</span>
</div>