.compare {
  position: relative;
  overflow: hidden;
  width: 100%;
  margin: 1rem 0;
  user-select: none;
  touch-action: none; /* three and four images follow a finger on both axes */
}

.compare.compare-2 {
  touch-action: pan-y; /* two images only need horizontal moves, so the page keeps scrolling */
}

/* The first image sets the box's height; the others are stacked on it and clipped to their regions. */
.compare img {
  display: block;
  width: 100%;
  height: auto;
  margin: 0;
}

.compare img + img {
  position: absolute;
  top: 0;
  left: 0;
  height: 100%;
}

.compare-region,
.compare-line {
  position: absolute;
  pointer-events: none;
}

.compare-region {
  overflow: hidden;
  display: flex;
  justify-content: center;
  align-items: flex-start;
}

.compare-label {
  padding: 0.5rem;
  color: #fff;
  font-size: 0.875rem;
  text-align: center;
  text-shadow:
    0 0 4px #000,
    0 0 4px #000;
}

.compare-line {
  background: #fff;
  box-shadow: 0 0 6px rgba(0, 0, 0, 0.5);
}

.compare-line-vertical {
  top: 0;
  width: 2px;
  transform: translateX(-50%);
}

.compare-line-horizontal {
  left: 0;
  width: 100%;
  height: 2px;
  transform: translateY(-50%);
}