.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  border: 2px solid transparent;
  cursor: pointer;
  transition: var(--transition-base);
  white-space: nowrap;
  text-decoration: none;
}

.btn:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

.btn:disabled,
.btn[aria-disabled="true"] {
  opacity: 0.45;
  cursor: not-allowed;
  pointer-events: none;
}

/* Sizes */
.btn--sm {
  height: 36px;
  padding: 0 var(--space-4);
  font-size: var(--text-sm);
}

.btn--md {
  height: 44px;
  padding: 0 var(--space-5);
  font-size: var(--text-base);
}

.btn--lg {
  height: 52px;
  padding: 0 var(--space-8);
  font-size: var(--text-md);
}

/* Primary */
.btn--primary {
  background-color: var(--color-primary);
  color: #ffffff;
  border-color: var(--color-primary);
}

.btn--primary:hover {
  background-color: var(--color-primary-hover);
  border-color: var(--color-primary-hover);
  color: #ffffff;
}

.btn--primary:active {
  background-color: #a8161b;
  border-color: #a8161b;
}

/* Secondary */
.btn--secondary {
  background-color: var(--color-secondary);
  color: #ffffff;
  border-color: var(--color-secondary);
}

.btn--secondary:hover {
  background-color: var(--color-secondary-hover);
  border-color: var(--color-secondary-hover);
  color: #ffffff;
}

/* Ghost (outlined) */
.btn--ghost {
  background-color: transparent;
  color: var(--color-primary);
  border-color: var(--color-primary);
}

.btn--ghost:hover {
  background-color: var(--color-primary);
  color: #ffffff;
}

/* Danger */
.btn--danger {
  background-color: var(--color-danger);
  color: #ffffff;
  border-color: var(--color-danger);
}

.btn--danger:hover {
  background-color: #a8161b;
  border-color: #a8161b;
  color: #ffffff;
}

/* Link style */
.btn--link {
  background-color: transparent;
  color: var(--color-primary);
  border-color: transparent;
  text-transform: none;
  letter-spacing: 0;
  padding: 0;
  height: auto;
  text-decoration: underline;
  font-weight: var(--weight-medium);
}

.btn--link:hover {
  color: var(--color-primary-hover);
}

/* Modifiers */
.btn--full-width {
  width: 100%;
}

.btn--icon-only {
  padding: 0;
  width: 44px;
  height: 44px;
  border-radius: var(--radius-md);
}

.btn--icon-only.btn--sm {
  width: 36px;
  height: 36px;
}

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

.btn--loading::after {
  content: '';
  position: absolute;
  inset: 50% auto auto 50%;
  transform: translate(-50%, -50%);
  width: 16px;
  height: 16px;
  border: 2px solid rgba(255, 255, 255, 0.4);
  border-top-color: #ffffff;
  border-radius: 50%;
  animation: btn-spin 0.6s linear infinite;
}

@keyframes btn-spin {
  to { transform: translate(-50%, -50%) rotate(360deg); }
}