Puzzle Piece Checkbox

<!--
  Author: @emma-lake
  License: MIT
  Tags: #buttons #css #interface #opensource #codepeek
-->
<label class="puzzle-check">
  <input type="checkbox" class="puzzle-check__input" />
  <span class="puzzle-check__slot">
    <span class="puzzle-check__piece"></span>
  </span>
  <span class="puzzle-check__label">Complete step</span>
</label>

/*
 * Author: @emma-lake
 * License: MIT
 * Tags: #buttons #css #interface #opensource #codepeek
 */

.puzzle-check {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  cursor: pointer;
  user-select: none;
  font-family: system-ui, sans-serif;
  color: #9a9aa5;
  font-size: 15px;
}
.puzzle-check__input {
  position: absolute;
  opacity: 0;
  width: 0;
  height: 0;
}
.puzzle-check__slot {
  position: relative;
  width: 30px;
  height: 30px;
  border-radius: 8px;
  border: 2px dashed #3a3a44;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: border-color 0.3s ease;
  animation: puzzle-slot-idle 2.4s ease-in-out infinite;
}
@keyframes puzzle-slot-idle {
  0%, 100% { border-color: #3a3a44; }
  50% { border-color: #55555f; }
}
.puzzle-check__piece {
  width: 20px;
  height: 20px;
  border-radius: 5px;
  background: #4b4b55;
  transform: translate(-14px, -14px) scale(0.7) rotate(-8deg);
  opacity: 0.6;
  transition: transform 0.4s cubic-bezier(0.34, 1.56, 0.64, 1), background 0.4s ease, opacity 0.4s ease;
  animation: puzzle-piece-wiggle 2.4s ease-in-out infinite;
}
@keyframes puzzle-piece-wiggle {
  0%, 100% { transform: translate(-14px, -14px) scale(0.7) rotate(-8deg); }
  50% { transform: translate(-11px, -11px) scale(0.72) rotate(-4deg); }
}
.puzzle-check__input:checked ~ .puzzle-check__slot {
  border-style: solid;
  border-color: #22d3ee;
  animation: none;
}
.puzzle-check__input:checked ~ .puzzle-check__slot .puzzle-check__piece {
  transform: translate(0, 0) scale(1) rotate(0deg);
  background: #22d3ee;
  opacity: 1;
  animation: puzzle-checked-glow 2s ease-in-out infinite;
}
@keyframes puzzle-checked-glow {
  0%, 100% { box-shadow: 0 0 8px rgba(34, 211, 238, 0.4); }
  50% { box-shadow: 0 0 16px rgba(34, 211, 238, 0.7); }
}
.puzzle-check__input:checked ~ .puzzle-check__label {
  color: #f4f4f5;
}