.checkbox {
  width: 2rem;
  height: 2rem;
  min-width: 2rem;
  min-height: 2rem;
  cursor: pointer;
  flex-shrink: 0;
  appearance: none;
  -webkit-appearance: none;
  border: 2px solid var(--color-gray-300, #d1d5db);
  border-radius: var(--border-radius-sm, 0.25rem);
  background-color: var(--color-white, #ffffff);
  position: relative;
  transition: background-color var(--transition-base, 200ms), border-color var(--transition-base, 200ms);
}

@media (max-width: 767px) {
  .checkbox {
    width: 2.5rem;
    height: 2.5rem;
    min-width: 2.5rem;
    min-height: 2.5rem;
  }
}

.checkbox:checked {
  background-color: var(--color-primary, #6366f1);
  border-color: var(--color-primary, #6366f1);
}

.checkbox:checked::after {
  content: "✓";
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  color: var(--color-white, #ffffff);
  font-size: 1rem;
  font-weight: var(--font-weight-bold, 700);
  line-height: 1;
}

@media (max-width: 767px) {
  .checkbox:checked::after {
    font-size: 1.25rem;
  }
}