/* ============================================
   AUTH — Sign-in, user menu, modals, profile,
   collections, achievements
   ============================================ */

/* ---- Theme Toggle ---- */
.theme-toggle {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  border: 1px solid var(--border-color);
  background: var(--bg-card);
  color: var(--text-primary);
  font-size: 14px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-base);
  padding: 0;
  line-height: 1;
  flex-shrink: 0;
}
.theme-toggle:hover {
  border-color: var(--border-light);
  background: var(--bg-card-hover);
  box-shadow: 0 0 12px rgba(76, 139, 245, 0.15);
}

/* ---- Sign In Button ---- */
.nav__auth-btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-1) var(--space-4);
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-full);
  color: var(--text-primary);
  font-size: var(--text-sm);
  font-weight: var(--font-medium);
  cursor: pointer;
  transition: all var(--transition-base);
  white-space: nowrap;
}
.nav__auth-btn:hover {
  border-color: var(--border-light);
  background: var(--bg-card-hover);
}
.nav__auth-btn svg {
  flex-shrink: 0;
}

/* ---- User Menu ---- */
.nav__user-menu {
  position: relative;
}
.nav__user-btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: 2px var(--space-3) 2px 2px;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-full);
  color: var(--text-primary);
  font-size: var(--text-sm);
  cursor: pointer;
  transition: all var(--transition-base);
  white-space: nowrap;
}
.nav__user-btn:hover {
  border-color: var(--border-light);
  background: var(--bg-card-hover);
}
.nav__user-avatar {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  object-fit: cover;
}
.nav__user-avatar--initials {
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--accent);
  color: #fff;
  font-size: var(--text-xs);
  font-weight: var(--font-bold);
}
.nav__user-name {
  font-weight: var(--font-medium);
  max-width: 100px;
  overflow: hidden;
  text-overflow: ellipsis;
}
.nav__user-level-badge {
  display: inline-flex;
  align-items: center;
  padding: 1px 6px;
  border-radius: var(--radius-full);
  font-size: 10px;
  font-weight: var(--font-bold);
  background: linear-gradient(135deg, rgba(76, 139, 245, 0.2), rgba(139, 92, 246, 0.2));
  color: var(--accent);
  border: 1px solid rgba(76, 139, 245, 0.2);
}

/* ---- Tier Badges ---- */
.tier-badge {
  display: inline-flex;
  align-items: center;
  padding: 1px 8px;
  border-radius: var(--radius-full);
  font-size: 10px;
  font-weight: var(--font-semibold);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}
.tier-badge--free {
  background: rgba(148, 163, 184, 0.15);
  color: var(--text-secondary);
  border: 1px solid rgba(148, 163, 184, 0.2);
}
.tier-badge--pro {
  background: linear-gradient(135deg, rgba(234, 179, 8, 0.2), rgba(245, 158, 11, 0.2));
  color: #fbbf24;
  border: 1px solid rgba(234, 179, 8, 0.3);
}

/* ---- Dropdown ---- */
.nav__user-dropdown {
  position: absolute;
  top: calc(100% + 8px);
  right: 0;
  width: 280px;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  box-shadow: 0 8px 30px rgba(0,0,0,0.45), 0 0 0 1px rgba(255,255,255,0.03);
  opacity: 0;
  visibility: hidden;
  transform: translateY(-4px) scale(0.97);
  transition: all 0.18s cubic-bezier(0.4, 0, 0.2, 1);
  z-index: 1000;
  overflow: hidden;
}
.nav__user-dropdown--open {
  opacity: 1;
  visibility: visible;
  transform: translateY(0) scale(1);
}
.nav__dropdown-divider {
  height: 1px;
  background: var(--border-color);
  margin: 0;
}

/* Profile card at top of dropdown */
.nav__dd-profile-card {
  padding: var(--space-4);
}
.nav__dd-profile-top {
  display: flex;
  gap: var(--space-3);
  align-items: center;
  margin-bottom: var(--space-3);
}
.nav__dd-avatar {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  object-fit: cover;
  flex-shrink: 0;
  border: 2px solid var(--border-color);
}
.nav__dd-avatar--initials {
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--accent);
  color: #fff;
  font-size: var(--text-sm);
  font-weight: var(--font-bold);
}
.nav__dd-info {
  flex: 1;
  min-width: 0;
}
.nav__dd-name {
  font-size: var(--text-sm);
  font-weight: var(--font-semibold);
  color: var(--text-bright);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.nav__dd-email {
  font-size: 11px;
  color: var(--text-muted);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.nav__dd-stats-row {
  display: flex;
  gap: var(--space-1);
  margin-bottom: var(--space-2);
}
.nav__dd-stat {
  flex: 1;
  text-align: center;
  padding: var(--space-2) 0;
  background: var(--bg-main);
  border-radius: var(--radius-md);
}
.nav__dd-stat-val {
  display: block;
  font-size: var(--text-sm);
  font-weight: var(--font-bold);
  color: var(--text-bright);
  line-height: 1.2;
}
.nav__dd-stat-lbl {
  display: block;
  font-size: 9px;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}
.nav__dd-xp-bar {
  height: 4px;
  background: var(--bg-main);
  border-radius: 2px;
  overflow: hidden;
  margin-bottom: 4px;
}
.nav__dd-xp-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--accent), #8b5cf6);
  border-radius: 2px;
  transition: width 0.6s ease;
  min-width: 2px;
}
.nav__dd-xp-text {
  font-size: 10px;
  color: var(--text-muted);
  text-align: center;
}

/* Menu items */
.nav__dd-menu-item {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  width: 100%;
  padding: 10px var(--space-4);
  background: none;
  border: none;
  color: var(--text-primary);
  font-size: var(--text-sm);
  cursor: pointer;
  transition: all 0.12s ease;
  text-align: left;
  text-decoration: none;
  font-family: inherit;
}
.nav__dd-menu-item svg {
  flex-shrink: 0;
  color: var(--text-muted);
  transition: color 0.12s ease;
}
.nav__dd-menu-item:hover {
  background: var(--bg-card-hover);
}
.nav__dd-menu-item:hover svg {
  color: var(--accent);
}
.nav__dd-menu-item--danger {
  color: #ef4444;
}
.nav__dd-menu-item--danger svg {
  color: #ef4444;
}
.nav__dd-menu-item--danger:hover {
  background: rgba(239, 68, 68, 0.08);
}

/* ============================================
   AUTH MODAL (Sign In)
   ============================================ */

.auth-modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.6);
  backdrop-filter: blur(4px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 10000;
  animation: fadeIn 0.2s ease;
}
.auth-modal {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-xl);
  width: 90%;
  max-width: 420px;
  padding: var(--space-8) var(--space-6);
  position: relative;
  animation: modalSlide 0.2s ease;
  text-align: center;
}
.auth-modal__icon {
  font-size: 2rem;
  margin-bottom: var(--space-3);
}
.auth-modal__title {
  font-size: var(--text-xl);
  font-weight: var(--font-bold);
  color: var(--text-bright);
  margin-bottom: var(--space-2);
}
.auth-modal__subtitle {
  font-size: var(--text-sm);
  color: var(--text-secondary);
  line-height: 1.5;
  margin-bottom: var(--space-6);
}
.auth-modal__providers {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}
.auth-provider-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-3);
  width: 100%;
  height: 48px;
  border-radius: var(--radius-lg);
  font-size: var(--text-sm);
  font-weight: var(--font-semibold);
  cursor: pointer;
  transition: all var(--transition-base);
  border: 1px solid var(--border-color);
}
.auth-provider-btn--google {
  background: var(--bg-elevated);
  color: var(--text-bright);
}
.auth-provider-btn--google:hover {
  background: var(--bg-card-hover);
  border-color: var(--border-light);
}
.auth-provider-btn--github {
  background: #24292e;
  color: #ffffff;
  border-color: #3d444d;
}
.auth-provider-btn--github:hover {
  background: #2d3339;
}
.auth-modal__divider {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  margin: var(--space-5) 0;
  font-size: var(--text-xs);
  color: var(--text-muted);
}
.auth-modal__divider::before,
.auth-modal__divider::after {
  content: '';
  flex: 1;
  height: 1px;
  background: var(--border-color);
}
.auth-modal__toggle {
  font-size: var(--text-xs);
  color: var(--text-secondary);
  margin-bottom: var(--space-4);
}
.auth-modal__toggle a {
  color: var(--accent);
  text-decoration: none;
  font-weight: var(--font-medium);
}
.auth-modal__toggle a:hover {
  text-decoration: underline;
}
.auth-modal__footer {
  font-size: 10px;
  color: var(--text-muted);
  line-height: 1.5;
}

/* ============================================
   ACCOUNT MODAL (Profile)
   ============================================ */

.account-modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.6);
  backdrop-filter: blur(4px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 10000;
  animation: fadeIn 0.2s ease;
}
@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}
.account-modal {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-xl);
  width: 90%;
  max-width: 480px;
  padding: var(--space-6);
  position: relative;
  animation: modalSlide 0.2s ease;
  max-height: 90vh;
  overflow-y: auto;
}
@keyframes modalSlide {
  from { transform: translateY(10px); opacity: 0; }
  to { transform: translateY(0); opacity: 1; }
}
.account-modal__close {
  position: absolute;
  top: var(--space-3);
  right: var(--space-3);
  background: none;
  border: none;
  color: var(--text-muted);
  font-size: 1.2rem;
  cursor: pointer;
  width: 28px;
  height: 28px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-md);
  transition: all var(--transition-base);
}
.account-modal__close:hover {
  background: var(--bg-card-hover);
  color: var(--text-primary);
}

.account-modal__header {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  margin-bottom: var(--space-5);
}
.account-modal__avatar {
  width: 56px;
  height: 56px;
  border-radius: 50%;
  object-fit: cover;
  flex-shrink: 0;
}
.account-modal__avatar--initials {
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--accent);
  color: #fff;
  font-size: var(--text-xl);
  font-weight: var(--font-bold);
}
.account-modal__info {
  flex: 1;
  min-width: 0;
}
.account-modal__name {
  font-size: var(--text-lg);
  font-weight: var(--font-semibold);
  color: var(--text-bright);
}
.account-modal__email {
  font-size: var(--text-sm);
  color: var(--text-muted);
  overflow: hidden;
  text-overflow: ellipsis;
}

/* ---- Level & XP Bar ---- */
.profile-level {
  margin-bottom: var(--space-5);
}
.profile-level__header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--space-2);
}
.profile-level__badge {
  display: inline-flex;
  align-items: center;
  padding: 2px 10px;
  border-radius: var(--radius-full);
  font-size: var(--text-xs);
  font-weight: var(--font-bold);
  background: linear-gradient(135deg, rgba(76, 139, 245, 0.15), rgba(139, 92, 246, 0.15));
  color: var(--accent);
  border: 1px solid rgba(76, 139, 245, 0.25);
}
.profile-level__text {
  font-size: var(--text-xs);
  color: var(--text-muted);
  font-weight: var(--font-medium);
}
.profile-level__bar {
  height: 8px;
  background: var(--bg-main);
  border-radius: var(--radius-full);
  overflow: hidden;
  border: 1px solid var(--border-color);
}
.profile-level__fill {
  height: 100%;
  background: linear-gradient(90deg, var(--accent), #8b5cf6);
  border-radius: var(--radius-full);
  transition: width 0.6s ease;
  min-width: 2px;
}

/* ---- Difficulty Breakdown (3 rings) ---- */
.difficulty-stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-3);
  margin-bottom: var(--space-5);
}
.difficulty-stat {
  text-align: center;
}
.progress-ring {
  width: 80px;
  height: 80px;
  margin: 0 auto var(--space-1);
}
.difficulty-stat__label {
  font-size: var(--text-xs);
  font-weight: var(--font-semibold);
  text-transform: uppercase;
  letter-spacing: 0.03em;
}

/* ---- Stats Row (4 mini cards) ---- */
.profile-stats-row {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-2);
  margin-bottom: var(--space-5);
}
.profile-stat-card {
  text-align: center;
  padding: var(--space-3) var(--space-2);
  background: var(--bg-main);
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-color);
}
.profile-stat-card__icon {
  font-size: 1.1rem;
  margin-bottom: 2px;
}
.profile-stat-card__value {
  font-size: var(--text-lg);
  font-weight: var(--font-bold);
  color: var(--text-bright);
  font-variant-numeric: tabular-nums;
}
.profile-stat-card__label {
  font-size: 10px;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.03em;
}

/* ---- Recent Activity ---- */
.profile-activity {
  margin-bottom: var(--space-5);
}
.profile-activity__label {
  font-size: var(--text-xs);
  font-weight: var(--font-semibold);
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: var(--space-2);
}
.profile-activity__item {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-1) 0;
  font-size: var(--text-xs);
  color: var(--text-primary);
}
.profile-activity__dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  flex-shrink: 0;
}
.profile-activity__title {
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

/* ---- Achievements Preview ---- */
.profile-achievements-preview {
  margin-bottom: var(--space-5);
}
.profile-achievements-preview__label {
  font-size: var(--text-xs);
  font-weight: var(--font-semibold);
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: var(--space-2);
}
.profile-achievements-preview__grid {
  display: flex;
  gap: var(--space-2);
  flex-wrap: wrap;
}
.achievement-mini {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-md);
  background: var(--bg-main);
  border: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.1rem;
}
.achievement-mini--more {
  font-size: var(--text-xs);
  color: var(--text-muted);
  font-weight: var(--font-semibold);
}

/* ---- Achievement Toast ---- */
.achievement-toast {
  position: fixed;
  bottom: var(--space-6);
  right: var(--space-6);
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-3) var(--space-5);
  background: var(--bg-card);
  border: 1px solid var(--accent-border);
  border-radius: var(--radius-lg);
  box-shadow: 0 8px 32px rgba(0,0,0,0.4), 0 0 20px rgba(76, 139, 245, 0.15);
  z-index: 20000;
  transform: translateX(120%);
  transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}
.achievement-toast--show {
  transform: translateX(0);
}
.achievement-toast__icon {
  font-size: 1.8rem;
}
.achievement-toast__content {
  min-width: 0;
}
.achievement-toast__label {
  font-size: 10px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--accent);
  font-weight: var(--font-semibold);
}
.achievement-toast__name {
  font-size: var(--text-sm);
  font-weight: var(--font-bold);
  color: var(--text-bright);
}

/* ---- Achievement Card (Grid) ---- */
.achievement-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: var(--space-4);
  text-align: center;
}
.achievement-card--locked {
  opacity: 0.4;
  filter: grayscale(1);
}
.achievement-card__icon {
  font-size: 1.5rem;
  margin-bottom: var(--space-2);
}
.achievement-card__name {
  font-size: var(--text-xs);
  font-weight: var(--font-semibold);
  color: var(--text-bright);
  margin-bottom: var(--space-1);
}
.achievement-card__desc {
  font-size: 10px;
  color: var(--text-muted);
  line-height: 1.4;
}

/* ============================================
   COLLECTIONS MODAL
   ============================================ */

.collections-modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.6);
  backdrop-filter: blur(4px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 10000;
  animation: fadeIn 0.2s ease;
}
.collections-modal {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-xl);
  width: 90%;
  max-width: 380px;
  animation: modalSlide 0.2s ease;
  overflow: hidden;
}
.collections-modal__header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--space-4) var(--space-5);
  border-bottom: 1px solid var(--border-color);
}
.collections-modal__header h3 {
  font-size: var(--text-sm);
  font-weight: var(--font-semibold);
  color: var(--text-bright);
}
.collections-modal__body {
  max-height: 240px;
  overflow-y: auto;
}
.collection-item {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-3) var(--space-5);
  cursor: pointer;
  transition: background var(--transition-base);
  font-size: var(--text-sm);
  color: var(--text-primary);
}
.collection-item:hover {
  background: var(--bg-card-hover);
}
.collection-item input[type="checkbox"] {
  accent-color: var(--accent);
}
.collection-item__name {
  flex: 1;
}
.collection-item__count {
  font-size: var(--text-xs);
  color: var(--text-muted);
}
.collections-modal__create {
  display: flex;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-5);
  border-top: 1px solid var(--border-color);
}
.collection-create__input {
  flex: 1;
  padding: var(--space-2) var(--space-3);
  background: var(--bg-main);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-size: var(--text-xs);
  font-family: var(--font-sans);
}
.collection-create__input::placeholder {
  color: var(--text-muted);
}
.collection-create__input:focus {
  outline: none;
  border-color: var(--accent);
}

/* ---- Problem Action Bar (LeetCode/Spotify-style) ---- */
.problem-action-bar {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-3) 0;
  margin-bottom: var(--space-2);
  flex-wrap: wrap;
}
.pab__btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 14px;
  background: var(--bg-main);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-full);
  color: var(--text-secondary);
  font-size: var(--text-xs);
  font-weight: var(--font-semibold);
  cursor: pointer;
  transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  font-family: inherit;
  white-space: nowrap;
  position: relative;
  overflow: hidden;
}
.pab__btn:hover {
  border-color: var(--border-light);
  color: var(--text-primary);
  background: var(--bg-card-hover);
  transform: translateY(-1px);
}
.pab__btn:active {
  transform: scale(0.95);
}
.pab__btn--active-green {
  background: rgba(34, 197, 94, 0.12);
  border-color: rgba(34, 197, 94, 0.3);
  color: #22c55e;
}
.pab__btn--active-green:hover {
  background: rgba(34, 197, 94, 0.18);
}
.pab__btn--active-yellow {
  background: rgba(245, 158, 11, 0.12);
  border-color: rgba(245, 158, 11, 0.3);
  color: #f59e0b;
}
.pab__btn--active-yellow:hover {
  background: rgba(245, 158, 11, 0.18);
}

/* Button click ripple animation */
@keyframes pab-ripple {
  0% { transform: scale(0); opacity: 0.4; }
  100% { transform: scale(2.5); opacity: 0; }
}
.pab__btn .pab__ripple {
  position: absolute;
  border-radius: 50%;
  width: 40px;
  height: 40px;
  background: currentColor;
  animation: pab-ripple 0.5s ease-out forwards;
  pointer-events: none;
}

/* Solved button pop animation */
@keyframes pab-pop-green {
  0% { transform: scale(0.95); }
  40% { transform: scale(1.08); box-shadow: 0 0 0 4px rgba(34,197,94,0.25); }
  100% { transform: scale(1); box-shadow: none; }
}
@keyframes pab-pop-yellow {
  0% { transform: scale(0.95); }
  40% { transform: scale(1.08); box-shadow: 0 0 0 4px rgba(245,158,11,0.25); }
  100% { transform: scale(1); box-shadow: none; }
}
.pab__btn--anim-green {
  animation: pab-pop-green 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);
}
.pab__btn--anim-yellow {
  animation: pab-pop-yellow 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);
}

/* XP gain floating text */
@keyframes xp-float {
  0% { opacity: 1; transform: translateY(0) scale(1); }
  70% { opacity: 1; transform: translateY(-30px) scale(1.1); }
  100% { opacity: 0; transform: translateY(-50px) scale(0.8); }
}
.pab__xp-float {
  position: absolute;
  top: -8px;
  right: -4px;
  font-size: 12px;
  font-weight: 700;
  color: #22c55e;
  pointer-events: none;
  animation: xp-float 1s ease-out forwards;
  z-index: 10;
  text-shadow: 0 1px 3px rgba(0,0,0,0.3);
}
.pab__sep {
  width: 1px;
  height: 20px;
  background: var(--border-color);
  margin: 0 var(--space-1);
}
.pab__icon-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 34px;
  height: 34px;
  border-radius: 50%;
  background: transparent;
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  padding: 0;
  position: relative;
}
.pab__icon-btn:hover {
  background: var(--bg-main);
  color: var(--text-primary);
  transform: scale(1.1);
}
.pab__icon-btn:active {
  transform: scale(0.9);
}
.pab__icon-btn--liked {
  color: #ef4444;
}
.pab__icon-btn--liked:hover {
  background: rgba(239, 68, 68, 0.1);
  color: #ef4444;
}

/* Heart pop animation */
@keyframes heart-pop {
  0% { transform: scale(0.8); }
  30% { transform: scale(1.3); }
  60% { transform: scale(0.95); }
  100% { transform: scale(1); }
}
.pab__icon-btn--anim-heart {
  animation: heart-pop 0.5s cubic-bezier(0.34, 1.56, 0.64, 1);
}

/* Bookmark save animation */
@keyframes bookmark-pop {
  0% { transform: scale(0.8) translateY(2px); }
  40% { transform: scale(1.2) translateY(-3px); }
  100% { transform: scale(1) translateY(0); }
}
.pab__icon-btn--anim-bookmark {
  animation: bookmark-pop 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);
}

/* Toast notification */
.qr-toast {
  position: fixed;
  bottom: var(--space-6);
  left: 50%;
  transform: translateX(-50%) translateY(20px) scale(0.9);
  padding: 10px 24px;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-full);
  color: var(--text-bright);
  font-size: var(--text-sm);
  font-weight: var(--font-medium);
  box-shadow: 0 8px 24px rgba(0,0,0,0.4);
  z-index: 20000;
  opacity: 0;
  transition: all 0.35s cubic-bezier(0.34, 1.56, 0.64, 1);
  white-space: nowrap;
}
.qr-toast--show {
  opacity: 1;
  transform: translateX(-50%) translateY(0) scale(1);
}
/* Toast with XP highlight */
.qr-toast--xp {
  border-color: rgba(34, 197, 94, 0.3);
  box-shadow: 0 8px 24px rgba(0,0,0,0.4), 0 0 16px rgba(34, 197, 94, 0.15);
}

/* Legacy support */
.problem-actions { display: none; }
.action-btn { display: none; }

/* Upgrade CTA */
.account-modal__upgrade {
  background: linear-gradient(135deg, rgba(234, 179, 8, 0.05), rgba(245, 158, 11, 0.08));
  border: 1px solid rgba(234, 179, 8, 0.2);
  border-radius: var(--radius-lg);
  padding: var(--space-4);
}
.account-modal__upgrade-title {
  font-size: var(--text-sm);
  font-weight: var(--font-semibold);
  color: #fbbf24;
  margin-bottom: var(--space-1);
}
.account-modal__upgrade-desc {
  font-size: var(--text-xs);
  color: var(--text-secondary);
  line-height: 1.5;
}

/* ---- Locked Problem Styles ---- */
.problem-row--locked {
  opacity: 0.65;
}
.problem-row--locked .td-title-link {
  color: var(--text-secondary);
}
.lock-icon {
  display: inline-flex;
  align-items: center;
  margin-left: var(--space-1);
  font-size: var(--text-xs);
  color: var(--text-muted);
}
.pro-badge {
  display: inline-block;
  font-size: 10px;
  font-weight: 700;
  letter-spacing: 0.04em;
  padding: 1px 6px;
  border-radius: 4px;
  background: linear-gradient(135deg, rgba(245, 183, 49, 0.18), rgba(245, 158, 11, 0.18));
  color: #fbbf24;
  border: 1px solid rgba(245, 183, 49, 0.25);
  margin-left: 6px;
  vertical-align: middle;
  line-height: 1.4;
}

/* Locked overlay for detail view */
.locked-overlay {
  position: relative;
  padding: var(--space-8) var(--space-6);
  text-align: center;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
}
.locked-overlay__icon {
  font-size: 2rem;
  margin-bottom: var(--space-3);
}
.locked-overlay__title {
  font-size: var(--text-lg);
  font-weight: var(--font-semibold);
  color: var(--text-bright);
  margin-bottom: var(--space-2);
}
.locked-overlay__desc {
  font-size: var(--text-sm);
  color: var(--text-secondary);
  margin-bottom: var(--space-4);
  max-width: 320px;
  margin-left: auto;
  margin-right: auto;
  line-height: 1.5;
}
.locked-overlay .btn {
  margin: 0 auto;
}

.solution-content--locked {
  filter: blur(8px);
  pointer-events: none;
  user-select: none;
  position: relative;
}

/* ============================================
   PAGINATION (LeetCode-style)
   ============================================ */

.pagination {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 4px;
  padding: var(--space-5) 0 var(--space-3);
}
.pagination__btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 36px;
  height: 36px;
  padding: 0 10px;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  background: var(--bg-card);
  color: var(--text-secondary);
  font-size: var(--text-sm);
  font-weight: var(--font-medium);
  cursor: pointer;
  transition: all 0.15s ease;
  font-family: inherit;
}
.pagination__btn:hover:not(.pagination__btn--disabled):not(.pagination__btn--active) {
  border-color: var(--border-light);
  color: var(--text-primary);
  background: var(--bg-card-hover);
}
.pagination__btn--active {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
  font-weight: var(--font-semibold);
}
.pagination__btn--arrow {
  padding: 0;
  min-width: 36px;
}
.pagination__btn--disabled {
  opacity: 0.35;
  cursor: not-allowed;
  pointer-events: none;
}
.pagination__ellipsis {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 36px;
  color: var(--text-muted);
  font-size: var(--text-sm);
}

/* ---- Responsive ---- */
@media (max-width: 768px) {
  .nav__user-name {
    display: none;
  }
  .nav__auth-btn span {
    display: none;
  }
  .nav__auth-btn {
    padding: var(--space-2);
  }
  .account-modal {
    width: 95%;
    padding: var(--space-4);
  }
  .difficulty-stats {
    gap: var(--space-2);
  }
  .profile-stats-row {
    grid-template-columns: repeat(2, 1fr);
  }
  .achievement-toast {
    right: var(--space-3);
    bottom: var(--space-3);
    left: var(--space-3);
  }
  .pagination__btn {
    min-width: 32px;
    height: 32px;
    font-size: var(--text-xs);
  }
}