/**
 * Button Component System
 * Variants: primary, secondary, ghost, outline, danger
 * Sizes: xs, sm, md, lg, xl
 * States: hover, active, disabled, loading
 *
 * @author Amit Haridas, ConcreteInfo
 */

/* ============================================
   BASE BUTTON
   ============================================ */
.btn,
.btn-primary,
.btn-secondary,
.btn-outline,
.btn-outline-secondary,
.btn-ghost,
.btn-ghost-active,
.btn-danger,
.btn-success,
.btn-warning,
.btn-info,
.btn-outline-danger,
.btn-outline-success {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-2);
  padding: var(--spacing-2-5) var(--spacing-4);
  font-family: var(--font-family-sans);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-semibold);
  line-height: var(--line-height-tight);
  text-decoration: none;
  border: 1.5px solid transparent;
  border-radius: var(--radius-lg);
  cursor: pointer;
  transition: all var(--transition-fast);
  user-select: none;
  white-space: nowrap;
  position: relative;
  overflow: hidden;
}

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

/* Icon in button */
.btn i,
.btn svg {
  flex-shrink: 0;
}

/* ============================================
   BUTTON SIZES
   ============================================ */
.btn-xs {
  padding: var(--spacing-1) var(--spacing-2);
  font-size: var(--font-size-xs);
  border-radius: var(--radius-md);
}

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

.btn-md {
  padding: var(--spacing-2-5) var(--spacing-4);
  font-size: var(--font-size-sm);
}

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

.btn-xl {
  padding: var(--spacing-4) var(--spacing-8);
  font-size: var(--font-size-lg);
  border-radius: var(--radius-xl);
}

/* ============================================
   BUTTON VARIANTS
   ============================================ */

/* Primary - Gradient */
.btn-primary {
  background: linear-gradient(135deg, var(--color-brand), var(--color-brand-light));
  color: var(--text-inverse);
  border-color: transparent;
  box-shadow: var(--shadow-sm);
}

.btn-primary:hover {
  background: linear-gradient(135deg, var(--color-brand-dark), var(--color-brand));
  transform: translateY(-1px);
  box-shadow: var(--shadow-primary);
}

.btn-primary:active {
  transform: translateY(0);
  box-shadow: var(--shadow-xs);
}

/* Secondary - Solid */
.btn-secondary {
  background-color: var(--color-gray-800);
  color: var(--text-inverse);
  border-color: var(--color-gray-800);
}

.btn-secondary:hover {
  background-color: var(--color-gray-700);
  border-color: var(--color-gray-700);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

/* Outline */
.btn-outline {
  background-color: transparent;
  color: var(--color-primary);
  border-color: var(--color-primary);
}

.btn-outline:hover {
  background-color: var(--color-primary);
  color: var(--text-inverse);
}

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

.btn-ghost:hover {
  background-color: var(--bg-tertiary);
  color: var(--text-primary);
}

.btn-ghost-active {
  background-color: var(--color-brand-50, hsl(var(--color-brand-h) var(--color-brand-s) var(--color-brand-l) / 0.08));
  color: var(--color-brand);
  border-color: transparent;
}

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

.btn-danger:hover {
  background-color: hsl(0, 84%, 50%);
  border-color: hsl(0, 84%, 50%);
  transform: translateY(-1px);
  box-shadow: 0 4px 12px hsl(0, 84%, 60%, 0.3);
}

/* Success */
.btn-success {
  background-color: var(--color-success);
  color: var(--text-inverse);
  border-color: var(--color-success);
}

.btn-success:hover {
  background-color: hsl(142, 76%, 32%);
  transform: translateY(-1px);
  box-shadow: 0 4px 12px hsl(142, 76%, 36%, 0.3);
}

/* Warning */
.btn-warning {
  background-color: var(--color-warning);
  color: var(--color-gray-900);
  border-color: var(--color-warning);
}

.btn-warning:hover {
  background-color: hsl(45, 93%, 40%);
  border-color: hsl(45, 93%, 40%);
  transform: translateY(-1px);
  box-shadow: 0 4px 12px hsl(45, 93%, 47%, 0.3);
}

/* Info */
.btn-info {
  background-color: var(--color-info);
  color: var(--text-inverse);
  border-color: var(--color-info);
}

.btn-info:hover {
  background-color: hsl(199, 89%, 38%);
  border-color: hsl(199, 89%, 38%);
  transform: translateY(-1px);
  box-shadow: 0 4px 12px hsl(199, 89%, 48%, 0.3);
}

/* Outline Danger */
.btn-outline-danger {
  background-color: transparent;
  color: var(--color-danger);
  border-color: var(--color-danger);
}

.btn-outline-danger:hover {
  background-color: var(--color-danger);
  color: var(--text-inverse);
}

/* Outline Success */
.btn-outline-success {
  background-color: transparent;
  color: var(--color-success);
  border-color: var(--color-success);
}

.btn-outline-success:hover {
  background-color: var(--color-success);
  color: var(--text-inverse);
}

/* ============================================
   BUTTON STATES
   ============================================ */
.btn:disabled,
.btn-disabled {
  opacity: 0.5;
  cursor: not-allowed;
  pointer-events: none;
}

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

.btn-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-primary.btn-loading::after {
  border-color: var(--text-inverse);
  border-top-color: transparent;
}

/* ============================================
   SPECIAL BUTTON TYPES
   ============================================ */

/* Icon only button */
.btn-icon {
  padding: var(--spacing-2-5);
  aspect-ratio: 1;
}

.btn-icon.btn-sm {
  padding: var(--spacing-2);
}

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

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

/* ============================================
   BUTTON GROUPS
   ============================================ */
.btn-group {
  display: inline-flex;
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}

.btn-group .btn {
  border-radius: 0;
  border-right-width: 0;
}

.btn-group .btn:first-child {
  border-top-left-radius: var(--radius-lg);
  border-bottom-left-radius: var(--radius-lg);
}

.btn-group .btn:last-child {
  border-top-right-radius: var(--radius-lg);
  border-bottom-right-radius: var(--radius-lg);
  border-right-width: 1.5px;
}

.btn-group .btn:hover {
  transform: none;
}

/* ============================================
   FAB (Floating Action Button)
   ============================================ */
.btn-fab {
  position: fixed;
  bottom: var(--spacing-6);
  right: var(--spacing-6);
  width: 3.5rem;
  height: 3.5rem;
  padding: 0;
  border-radius: var(--radius-full);
  box-shadow: var(--shadow-lg);
  z-index: var(--z-sticky);
}

.btn-fab:hover {
  transform: translateY(-2px) scale(1.05);
  box-shadow: var(--shadow-xl);
}