Neon Flicker Checkbox

<!--
  Author: @opalok
  License: MIT
  Tags: #neon
-->
<label class="neon-check">
  <input type="checkbox" class="neon-check__input" />
  <span class="neon-check__box">
    <svg class="neon-check__mark" viewBox="0 0 24 24" fill="none">
      <path class="neon-check__mark-path" d="M4 12.5L9.5 18L20 6.5" stroke="currentColor" stroke-width="3" stroke-linecap="round" stroke-linejoin="round"/>
    </svg>
  </span>
  <span class="neon-check__label">Enable notifications</span>
</label>

/*
 * Author: @opalok
 * License: MIT
 * Tags: #neon
 */

.neon-check {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  cursor: pointer;
  user-select: none;
  font-family: system-ui, sans-serif;
  color: #7d7d8a;
  font-size: 16px;
}

.neon-check__input {
  position: absolute;
  opacity: 0;
  width: 0;
  height: 0;
}

.neon-check__box {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 26px;
  height: 26px;
  border-radius: 6px;
  background: #0d0d12;
  border: 2px solid #2c2c38;
  color: transparent;
  transition: border-color 0.3s ease, box-shadow 0.3s ease, color 0.3s ease;
}

.neon-check__mark-path {
  stroke-dasharray: 24;
  stroke-dashoffset: 24;
  transition: stroke-dashoffset 0.3s ease 0.1s;
}

.neon-check__input:checked ~ .neon-check__box {
  border-color: #ff2ed1;
  color: #ff2ed1;
  box-shadow:
    0 0 6px #ff2ed1,
    0 0 16px rgba(255, 46, 209, 0.6),
    inset 0 0 8px rgba(255, 46, 209, 0.4);
  animation: neon-flicker 1.8s linear infinite;
}

.neon-check__input:checked ~ .neon-check__box .neon-check__mark-path {
  stroke-dashoffset: 0;
}

.neon-check__input:focus-visible ~ .neon-check__box {
  outline: 2px solid #ff2ed1;
  outline-offset: 3px;
}

.neon-check__input:checked ~ .neon-check__label {
  color: #ff2ed1;
  text-shadow: 0 0 8px rgba(255, 46, 209, 0.5);
}

.neon-check__label {
  transition: color 0.3s ease, text-shadow 0.3s ease;
}

@keyframes neon-flicker {
  0%, 19%, 21%, 23%, 25%, 54%, 56%, 100% {
    box-shadow:
      0 0 6px #ff2ed1,
      0 0 16px rgba(255, 46, 209, 0.6),
      inset 0 0 8px rgba(255, 46, 209, 0.4);
  }
  20%, 22%, 24%, 55% {
    box-shadow: none;
  }
}