.prism {
  --intensity: 1;
  --scaleFactor: 1.01;
  --blur: 5;
  --redTop: 0;
  --redLeft: 0;
  --greenTop: 0;
  --greenLeft: 0;
  --blueTop: 0;
  --blueLeft: 0;
  position: relative;
  top: 0;
  color: var(--fg);
  background: var(--bg);
  border: 2px solid #333;
  transition: border-color 0.2s linear, top 0.1s ease;
}
.prism > .red, .prism > .green, .prism > .blue {
  position: absolute;
  width: calc(var(--scaleFactor) * 100%);
  height: calc(var(--scaleFactor) * 100%);
  z-index: -1;
  border-radius: inherit;
  filter: blur(calc(var(--blur) * 1px));
  mix-blend-mode: screen;
  opacity: var(--intensity);
}
.prism > .red {
  top: calc(var(--redTop) * 1px);
  left: calc(var(--redLeft) * 1px);
  background: red;
}
.prism > .green {
  top: calc(var(--greenTop) * 1px);
  left: calc(var(--greenLeft) * 1px);
  background: lime;
}
.prism > .blue {
  top: calc(var(--blueTop) * 1px);
  left: calc(var(--blueLeft) * 1px);
  background: blue;
}
.prism:focus {
  outline: none;
  border-color: #fff;
}
.prism:active {
  top: -4px;
}

button {
  -webkit-appearance: none;
  -moz-appearance: none;
  appearance: none;
  border: none;
  border-radius: var(--border-radius, 100em);
  padding: 1em 2em;
  font-weight: bolder;
}
button:hover {
  cursor: pointer;
}
button + button {
  margin-left: 1em;
}

body {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg);
}

:root {
  --bg: #222;
  --fg: #fff;
  --border-radius: 9em;
  font-size: 30px;
}