.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  min-height: 44px;
  padding: var(--space-2) var(--space-5);
  border: 1px solid transparent;
  border-radius: var(--radius-md);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: 600;
  line-height: 1;
  text-decoration: none;
  cursor: pointer;
  transition: background-color var(--dur-fast) var(--ease-out),
              border-color var(--dur-fast) var(--ease-out),
              color var(--dur-fast) var(--ease-out),
              transform var(--dur-fast) var(--ease-out);
}

.btn + .btn {
  margin-inline-start: var(--space-2);
}

.btn:active {
  transform: translateY(1px);
}

.btn:disabled,
.btn[aria-disabled="true"] {
  cursor: not-allowed;
  opacity: .55;
  transform: none;
}

.btn--primary {
  background: var(--color-accent);
  color: var(--color-on-accent);
}

.btn--primary:hover:not(:disabled) {
  background: var(--color-accent-hover);
}

.btn--secondary {
  background: transparent;
  border-color: var(--color-primary);
  color: var(--color-primary);
}

.btn--secondary:hover:not(:disabled) {
  background: var(--color-muted);
}

.btn--ghost {
  background: transparent;
  color: var(--color-primary);
}

.btn--ghost:hover:not(:disabled) {
  background: var(--color-muted);
}

.btn--destructive {
  background: var(--color-destructive);
  color: var(--color-on-destructive);
}

.btn--destructive:hover:not(:disabled) {
  background: var(--color-accent-hover);
}

.btn--sm {
  min-height: 36px;
  padding: var(--space-1) var(--space-4);
  font-size: var(--text-xs);
}

.btn--icon {
  min-width: 44px;
  padding: var(--space-2);
}

.btn .icon {
  pointer-events: none;
}

.btn--loading {
  position: relative;
  color: transparent !important;
  pointer-events: none;
}

.btn--loading::after {
  content: "";
  position: absolute;
  width: 16px;
  height: 16px;
  border: 2px solid currentColor;
  border-top-color: transparent;
  border-radius: var(--radius-full);
  color: inherit;
  animation: btn-spin var(--dur-slow) linear infinite;
}

.btn--primary.btn--loading::after,
.btn--destructive.btn--loading::after {
  color: var(--color-on-accent);
}

.btn--secondary.btn--loading::after,
.btn--ghost.btn--loading::after {
  color: var(--color-primary);
}

@keyframes btn-spin {
  to { transform: rotate(360deg); }
}

@media (prefers-reduced-motion: reduce) {
  .btn--loading::after {
    animation: none;
  }
}