/**
 * Button Component Styles
 * @module atoms/button
 *
 * Uses project design tokens. Single-dash naming for compatibility.
 */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-4);
  font-family: var(--font-sans);
  font-size: var(--text-base);
  font-weight: var(--font-semibold);
  line-height: 1.5;
  border-radius: var(--radius-md);
  border: 1px solid transparent;
  cursor: pointer;
  text-decoration: none;
  transition: background var(--transition-fast), color var(--transition-fast), border-color var(--transition-fast), box-shadow var(--transition-fast), transform var(--transition-fast), opacity var(--transition-fast);
  user-select: none;
  white-space: nowrap;
}

.btn:hover {
  text-decoration: none;
}

.btn:focus-visible {
  outline: 2px solid var(--entity-focus-color, currentColor);
  outline-offset: 2px;
  box-shadow: none;
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.btn:active:not(:disabled) {
  transform: scale(0.98);
}

/* ==========================================================================
   Variants
   ========================================================================== */

/* Primary - brand filled */
.btn-primary {
  background: var(--color-brand);
  color: var(--color-text-contrast);
  border-color: var(--color-brand);
}

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

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

/* Secondary - outline */
.btn-secondary {
  background: transparent;
  color: var(--color-text-main);
  border-color: var(--color-border-subtle);
}

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

.btn-secondary:active:not(:disabled) {
  background: var(--color-bg-active);
}

/* Ghost - minimal, transparent */
.btn-ghost {
  background: transparent;
  color: var(--color-text-main);
  border-color: transparent;
}

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

.btn-ghost:active:not(:disabled) {
  background: var(--color-bg-active);
}

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

.btn-danger:hover:not(:disabled) {
  background: var(--color-danger-hover);
  border-color: var(--color-danger-hover);
}

/* Danger outline - outline only, fills on hover */
.btn-danger-outline {
  background: transparent;
  color: var(--color-danger);
  border-color: var(--color-danger);
}

.btn-danger-outline:hover:not(:disabled) {
  background: var(--color-danger);
  color: var(--color-text-contrast);
}

/* Save - icon button with muted brand, brand on hover/active */
.btn-save {
  background: var(--color-brand-muted);
  color: var(--color-brand);
  border-color: var(--color-brand-muted);
  padding: var(--space-2);
  min-width: auto;
}

.btn-save:hover:not(:disabled) {
  background: var(--color-brand);
  color: var(--color-text-contrast);
  border-color: var(--color-brand);
}

.btn-save:active:not(:disabled),
.btn-save.is-active {
  background: var(--color-brand);
  color: var(--color-text-contrast);
  border-color: var(--color-brand);
}

.btn-save .material-symbols-rounded {
  font-size: var(--icon-md);
}

/* Text - minimal text button */
.btn-text {
  background: transparent;
  color: var(--color-text-main);
  border-color: transparent;
  padding-left: var(--space-2);
  padding-right: var(--space-2);
}

.btn-text:hover:not(:disabled) {
  background: var(--color-bg-hover);
}

/* ==========================================================================
   Sizes
   ========================================================================== */

.btn-sm {
  padding: var(--space-2) var(--space-3);
  font-size: var(--text-sm);
  gap: var(--space-2);
}

.btn-lg {
  padding: var(--space-3) var(--space-6);
  font-size: var(--text-base);
  gap: var(--space-3);
}

.btn-xl {
  padding: var(--space-4) var(--space-8);
  font-size: var(--text-lg);
  gap: var(--space-3);
}

/* ==========================================================================
   Modifiers
   ========================================================================== */

/* Icon only */
.btn-icon {
  padding: var(--space-2);
  aspect-ratio: 1;
}

.btn-icon.btn-sm {
  padding: var(--space-1);
}

.btn-icon.btn-lg {
  padding: var(--space-3);
}

/* Full width */
.btn-block {
  width: 100%;
}

/* ==========================================================================
   States
   ========================================================================== */

/* Loading state */
.btn.is-loading {
  position: relative;
  color: transparent;
  pointer-events: none;
}

.btn.is-loading::after {
  content: "";
  position: absolute;
  width: 1em;
  height: 1em;
  border: 2px solid currentColor;
  border-top-color: transparent;
  border-radius: var(--radius-full);
  animation: spin 0.6s linear infinite;
}

.btn.is-loading.btn-primary::after,
.btn.is-loading.btn-danger::after {
  border-color: rgba(255, 255, 255, 0.3);
  border-top-color: var(--color-text-contrast);
}

/* ==========================================================================
   Mobile touch targets (Apple HIG: 44px minimum)
   ========================================================================== */

@media (--mobile) {
  .btn {
    min-height: 44px;
  }

  .btn-sm {
    min-height: 44px;
  }

  .btn-icon {
    min-width: 44px;
    min-height: 44px;
  }

  .btn-icon.btn-sm {
    min-width: 44px;
    min-height: 44px;
  }
}