.testcard {
  position: relative;
  align-self: stretch;
  justify-self: stretch;
  z-index: 0;
  overflow: hidden;
  background: var(--bg);
}

.testcard-svg {
  display: block;
  width: 100%;
  height: 100%;
}

.testcard-label {
  fill: var(--fg);
  font-family: var(--font-mono);
  font-size: 22px;
  text-anchor: middle;
}

/* Every channel fills the same cell; only the current one is shown. */
.testcard-ch {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
}

.testcard-ch[hidden] {
  display: none;
}

.testcard-static {
  image-rendering: pixelated;
}

.testcard-nosignal {
  background: var(--bar-blue);
}

.testcard-osd {
  position: absolute;
  top: var(--space-5);
  left: var(--space-5);
  font-family: var(--font-mono);
  font-size: var(--step-1);
  line-height: 1.3;
  color: #fff;
}