/* ========================================
   UI Component Library
   Design System v2.0 - GPT/Gemini Inspired
   ======================================== */

/* --- Buttons --- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  padding: 8px 16px;
  font-size: var(--font-size-md);
  font-weight: var(--font-weight-medium);
  line-height: var(--line-height-normal);
  border: 1px solid transparent;
  border-radius: var(--radius-lg);
  cursor: pointer;
  transition: all var(--transition-fast);
  text-decoration: none;
  white-space: nowrap;
  user-select: none;
  outline: none;
  font-family: inherit;
}
.btn:focus-visible {
  box-shadow: var(--shadow-glow);
}
.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  pointer-events: none;
}

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

.btn-secondary {
  background: transparent;
  color: var(--color-text-primary);
  border-color: var(--color-border);
}
.btn-secondary:hover:not(:disabled) {
  background: var(--color-bg-hover);
  border-color: var(--color-border-heavy);
}

.btn-ghost {
  background: transparent;
  color: var(--color-text-secondary);
  border-color: transparent;
}
.btn-ghost:hover:not(:disabled) {
  background: var(--color-bg-hover);
  color: var(--color-text-primary);
}

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

.btn-sm { padding: 4px 10px; font-size: var(--font-size-sm); }
.btn-lg { padding: 12px 24px; font-size: var(--font-size-lg); }
.btn-icon { padding: 8px; min-width: 36px; min-height: 36px; }
.btn-icon.btn-sm { padding: 4px; min-width: 28px; min-height: 28px; }

.btn-block { width: 100%; }

/* --- Inputs --- */
.input {
  display: block;
  width: 100%;
  padding: 10px 14px;
  font-size: var(--font-size-md);
  font-family: inherit;
  color: var(--color-text-primary);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  outline: none;
  transition: all var(--transition-fast);
  line-height: var(--line-height-normal);
}
.input::placeholder {
  color: var(--color-text-placeholder);
}
.input:hover {
  border-color: var(--color-border-heavy);
}
.input:focus {
  border-color: var(--color-border-focus);
  box-shadow: var(--shadow-glow);
}
.input-error { border-color: var(--color-danger); }
.input-error:focus { box-shadow: 0 0 0 3px rgba(239, 68, 68, 0.15); }

.input-group {
  position: relative;
  display: flex;
  align-items: center;
}
.input-group .input {
  padding-right: 40px;
}
.input-group .input-icon {
  position: absolute;
  right: 12px;
  color: var(--color-text-tertiary);
  pointer-events: none;
}

/* --- Cards --- */
.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-2xl);
  box-shadow: var(--shadow-sm);
}
.card-body { padding: var(--spacing-5); }
.card-header {
  padding: var(--spacing-4) var(--spacing-5);
  border-bottom: 1px solid var(--color-border);
  font-weight: var(--font-weight-semibold);
}
.card-footer {
  padding: var(--spacing-4) var(--spacing-5);
  border-top: 1px solid var(--color-border);
}

/* --- Modals --- */
.modal-overlay {
  position: fixed;
  inset: 0;
  z-index: 10000;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(0, 0, 0, 0.5);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  animation: fadeIn 200ms ease;
}
.modal {
  background: var(--color-surface-modal);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-4xl);
  box-shadow: var(--shadow-3xl);
  width: 90vw;
  max-width: 480px;
  max-height: 85vh;
  display: flex;
  flex-direction: column;
  animation: modalSlideIn 300ms cubic-bezier(0.16, 1, 0.3, 1);
}
.modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--spacing-5) var(--spacing-6);
  border-bottom: 1px solid var(--color-border);
  flex-shrink: 0;
}
.modal-title {
  font-size: var(--font-size-2xl);
  font-weight: var(--font-weight-semibold);
  color: var(--color-text-primary);
}
.modal-close {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  border-radius: var(--radius-lg);
  color: var(--color-text-secondary);
  cursor: pointer;
  transition: all var(--transition-fast);
  border: none;
  background: none;
  font-size: 20px;
}
.modal-close:hover {
  background: var(--color-bg-hover);
  color: var(--color-text-primary);
}
.modal-body {
  padding: var(--spacing-6);
  overflow-y: auto;
  flex: 1;
}
.modal-footer {
  display: flex;
  justify-content: flex-end;
  gap: var(--spacing-2);
  padding: var(--spacing-4) var(--spacing-6);
  border-top: 1px solid var(--color-border);
  flex-shrink: 0;
}

/* --- Form Groups --- */
.form-group {
  margin-bottom: var(--spacing-5);
}
.form-label {
  display: block;
  margin-bottom: var(--spacing-1);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  color: var(--color-text-secondary);
}
.form-hint {
  margin-top: var(--spacing-1);
  font-size: var(--font-size-xs);
  color: var(--color-text-tertiary);
}
.form-error {
  margin-top: var(--spacing-1);
  font-size: var(--font-size-xs);
  color: var(--color-danger);
}

/* --- Divider --- */
.divider {
  height: 1px;
  background: var(--color-border);
  border: none;
  margin: var(--spacing-4) 0;
}
.divider-text {
  display: flex;
  align-items: center;
  gap: var(--spacing-3);
  color: var(--color-text-tertiary);
  font-size: var(--font-size-sm);
}
.divider-text::before,
.divider-text::after {
  content: '';
  flex: 1;
  height: 1px;
  background: var(--color-border);
}

/* --- Badge --- */
.badge {
  display: inline-flex;
  align-items: center;
  padding: 2px 8px;
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-medium);
  border-radius: var(--radius-full);
  line-height: var(--line-height-tight);
}
.badge-accent { background: var(--color-accent-soft); color: var(--color-accent); }
.badge-danger { background: var(--color-danger-soft); color: var(--color-danger); }
.badge-warning { background: var(--color-warning-soft); color: var(--color-warning); }
.badge-success { background: var(--color-success-soft); color: var(--color-success); }

/* --- Toast --- */
.toast-container {
  position: fixed;
  top: var(--spacing-4);
  left: 50%;
  transform: translateX(-50%);
  z-index: 99999;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--spacing-2);
  pointer-events: none;
}
.toast {
  padding: 10px 20px;
  background: var(--color-surface-modal);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-full);
  box-shadow: var(--shadow-xl);
  font-size: var(--font-size-md);
  color: var(--color-text-primary);
  animation: toastIn 300ms cubic-bezier(0.16, 1, 0.3, 1);
  pointer-events: auto;
  display: flex;
  align-items: center;
  gap: var(--spacing-2);
}

/* --- Skeleton Loading --- */
.skeleton {
  background: linear-gradient(90deg, var(--color-bg-tertiary) 0%, var(--color-bg-hover) 50%, var(--color-bg-tertiary) 100%);
  background-size: 200% 100%;
  animation: shimmer 1.5s infinite;
  border-radius: var(--radius-lg);
}
@keyframes shimmer {
  0% { background-position: 200% 0; }
  100% { background-position: -200% 0; }
}

/* --- Avatar --- */
.avatar {
  width: 32px;
  height: 32px;
  border-radius: var(--radius-full);
  overflow: hidden;
  flex-shrink: 0;
  background: var(--color-bg-tertiary);
  display: flex;
  align-items: center;
  justify-content: center;
}
.avatar img { width: 100%; height: 100%; object-fit: cover; }
.avatar-sm { width: 24px; height: 24px; }
.avatar-lg { width: 40px; height: 40px; }
.avatar-xl { width: 56px; height: 56px; }

/* --- Tooltip --- */
.tooltip {
  position: relative;
  display: inline-flex;
}
.tooltip-content {
  position: absolute;
  bottom: calc(100% + 6px);
  left: 50%;
  transform: translateX(-50%);
  padding: 4px 10px;
  background: var(--color-text-primary);
  color: var(--color-text-inverse);
  font-size: var(--font-size-xs);
  border-radius: var(--radius-md);
  white-space: nowrap;
  pointer-events: none;
  opacity: 0;
  transition: opacity var(--transition-fast);
  z-index: 100;
}
.tooltip:hover .tooltip-content { opacity: 1; }

/* --- Scrollbar --- */
.custom-scrollbar::-webkit-scrollbar { width: 6px; }
.custom-scrollbar::-webkit-scrollbar-track { background: transparent; }
.custom-scrollbar::-webkit-scrollbar-thumb {
  background: var(--color-border);
  border-radius: var(--radius-full);
}
.custom-scrollbar::-webkit-scrollbar-thumb:hover { background: var(--color-border-heavy); }

/* --- Animations --- */
@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}
@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}
@keyframes fadeInDown {
  from { opacity: 0; transform: translateY(-8px); }
  to { opacity: 1; transform: translateY(0); }
}
@keyframes modalSlideIn {
  from { opacity: 0; transform: translateY(16px) scale(0.97); }
  to { opacity: 1; transform: translateY(0) scale(1); }
}
@keyframes modalSlideUp {
  from { transform: translateY(100%); }
  to { transform: translateY(0); }
}
@keyframes toastIn {
  from { opacity: 0; transform: translateY(-12px) scale(0.95); }
  to { opacity: 1; transform: translateY(0) scale(1); }
}
@keyframes spin {
  to { transform: rotate(360deg); }
}
@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.5; }
}
@keyframes slideInLeft {
  from { transform: translateX(-100%); }
  to { transform: translateX(0); }
}
@keyframes slideInRight {
  from { transform: translateX(100%); }
  to { transform: translateX(0); }
}

.animate-fade-in { animation: fadeIn var(--transition-base) ease; }
.animate-fade-in-up { animation: fadeInUp var(--transition-slow) ease; }
.animate-fade-in-down { animation: fadeInDown var(--transition-slow) ease; }
.animate-spin { animation: spin 1s linear infinite; }
.animate-pulse { animation: pulse 2s cubic-bezier(0.4, 0, 0.6, 1) infinite; }

/* --- Utility Classes --- */
.flex { display: flex; }
.flex-col { flex-direction: column; }
.flex-row { flex-direction: row; }
.flex-wrap { flex-wrap: wrap; }
.flex-1 { flex: 1; }
.items-center { align-items: center; }
.items-start { align-items: flex-start; }
.items-end { align-items: flex-end; }
.justify-center { justify-content: center; }
.justify-between { justify-content: space-between; }
.justify-end { justify-content: flex-end; }
.gap-1 { gap: var(--spacing-1); }
.gap-2 { gap: var(--spacing-2); }
.gap-3 { gap: var(--spacing-3); }
.gap-4 { gap: var(--spacing-4); }
.gap-5 { gap: var(--spacing-5); }
.gap-6 { gap: var(--spacing-6); }

.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.text-xs { font-size: var(--font-size-xs); }
.text-sm { font-size: var(--font-size-sm); }
.text-base { font-size: var(--font-size-base); }
.text-md { font-size: var(--font-size-md); }
.text-lg { font-size: var(--font-size-lg); }
.text-xl { font-size: var(--font-size-xl); }
.text-2xl { font-size: var(--font-size-2xl); }
.text-3xl { font-size: var(--font-size-3xl); }

.font-medium { font-weight: var(--font-weight-medium); }
.font-semibold { font-weight: var(--font-weight-semibold); }
.font-bold { font-weight: var(--font-weight-bold); }

.text-primary { color: var(--color-text-primary); }
.text-secondary { color: var(--color-text-secondary); }
.text-tertiary { color: var(--color-text-tertiary); }
.text-accent { color: var(--color-accent); }
.text-danger { color: var(--color-danger); }

.truncate {
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.w-full { width: 100%; }
.h-full { height: 100%; }

.p-0 { padding: 0; }
.p-2 { padding: var(--spacing-2); }
.p-3 { padding: var(--spacing-3); }
.p-4 { padding: var(--spacing-4); }
.p-5 { padding: var(--spacing-5); }
.p-6 { padding: var(--spacing-6); }

.m-0 { margin: 0; }
.mt-1 { margin-top: var(--spacing-1); }
.mt-2 { margin-top: var(--spacing-2); }
.mt-3 { margin-top: var(--spacing-3); }
.mt-4 { margin-top: var(--spacing-4); }
.mt-5 { margin-top: var(--spacing-5); }
.mt-6 { margin-top: var(--spacing-6); }
.mb-1 { margin-bottom: var(--spacing-1); }
.mb-2 { margin-bottom: var(--spacing-2); }
.mb-3 { margin-bottom: var(--spacing-3); }
.mb-4 { margin-bottom: var(--spacing-4); }
.mb-5 { margin-bottom: var(--spacing-5); }
.mb-6 { margin-bottom: var(--spacing-6); }
.ml-auto { margin-left: auto; }
.mr-auto { margin-right: auto; }

.relative { position: relative; }
.absolute { position: absolute; }
.fixed { position: fixed; }
.inset-0 { inset: 0; }

.rounded-sm { border-radius: var(--radius-sm); }
.rounded-md { border-radius: var(--radius-md); }
.rounded-lg { border-radius: var(--radius-lg); }
.rounded-xl { border-radius: var(--radius-xl); }
.rounded-2xl { border-radius: var(--radius-2xl); }
.rounded-3xl { border-radius: var(--radius-3xl); }
.rounded-4xl { border-radius: var(--radius-4xl); }
.rounded-full { border-radius: var(--radius-full); }

.shadow-sm { box-shadow: var(--shadow-sm); }
.shadow-md { box-shadow: var(--shadow-md); }
.shadow-lg { box-shadow: var(--shadow-lg); }
.shadow-xl { box-shadow: var(--shadow-xl); }

.cursor-pointer { cursor: pointer; }
.select-none { user-select: none; }
.overflow-hidden { overflow: hidden; }
.overflow-auto { overflow: auto; }

.hidden { display: none; }
.block { display: block; }

.border { border: 1px solid var(--color-border); }
.border-b { border-bottom: 1px solid var(--color-border); }
.border-t { border-top: 1px solid var(--color-border); }

.bg-surface { background: var(--color-surface); }
.bg-primary { background: var(--color-bg-primary); }
.bg-secondary { background: var(--color-bg-secondary); }

/* --- Loading Spinner --- */
.spinner {
  width: 20px;
  height: 20px;
  border: 2px solid var(--color-border);
  border-top-color: var(--color-accent);
  border-radius: 50%;
  animation: spin 0.6s linear infinite;
}
.spinner-sm { width: 14px; height: 14px; border-width: 1.5px; }
.spinner-lg { width: 28px; height: 28px; border-width: 3px; }

/* --- Empty State --- */
.empty-state {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: var(--spacing-12);
  text-align: center;
  color: var(--color-text-tertiary);
}
.empty-state-icon {
  font-size: 48px;
  margin-bottom: var(--spacing-4);
  opacity: 0.3;
}
.empty-state-title {
  font-size: var(--font-size-2xl);
  font-weight: var(--font-weight-semibold);
  color: var(--color-text-primary);
  margin-bottom: var(--spacing-2);
}
.empty-state-desc {
  font-size: var(--font-size-md);
  max-width: 360px;
  line-height: var(--line-height-relaxed);
}

/* --- Responsive --- */
@media (max-width: 768px) {
  .modal { border-radius: var(--radius-2xl) var(--radius-2xl) 0 0; margin-top: auto; max-height: 90vh; }
  .modal-body { padding: var(--spacing-4); }
  .modal-header { padding: var(--spacing-4); }
  .modal-footer { padding: var(--spacing-3) var(--spacing-4); }
  .hide-mobile { display: none !important; }
}
@media (min-width: 769px) {
  .hide-desktop { display: none !important; }
}