.grammar-page {
  --grammar-font: 'Onest', -apple-system, BlinkMacSystemFont, sans-serif;
  --grammar-primary: var(--primary-600);
  --grammar-primary-dark: var(--primary-700);
  --grammar-success: var(--success-500);
  --grammar-warning: var(--warning-500);
  --grammar-danger: var(--danger-500);
  --grammar-surface: #ffffff;
  --grammar-surface-alt: #f8fafc;
  --grammar-text: #0f172a;
  --grammar-text-muted: #64748b;
  --grammar-border: #e2e8f0;
  --grammar-radius: 16px;
  --grammar-radius-sm: 10px;

  font-family: var(--grammar-font);
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 1rem 3rem;
}

/* Breadcrumb */
.grammar-breadcrumb {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.875rem;
  color: var(--grammar-text-muted);
  margin-bottom: 1.5rem;
  flex-wrap: wrap;
}

.grammar-breadcrumb a {
  color: var(--grammar-primary);
  text-decoration: none;
  font-weight: 500;
}

.grammar-breadcrumb a:hover {
  text-decoration: underline;
}

.grammar-breadcrumb svg {
  opacity: 0.5;
  flex-shrink: 0;
}

/* Hero */
.topic-hero {
  position: relative;
  border-radius: var(--grammar-radius);
  padding: 2rem;
  margin-bottom: 1.5rem;
  overflow: hidden;
  color: #fff !important;
}

.topic-hero--a {
  background: linear-gradient(135deg, #06b6d4 0%, #3b82f6 100%);
}

.topic-hero--b {
  background: linear-gradient(135deg, #f97316 0%, var(--danger-500) 100%);
}

.topic-hero--c {
  background: linear-gradient(135deg, #ec4899 0%, var(--primary-500) 100%);
}

.topic-hero__bg-shapes {
  position: absolute;
  inset: 0;
  overflow: hidden;
  pointer-events: none;
}

.topic-hero .shape {
  position: absolute;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.1);
}

.topic-hero .shape--1 {
  width: 200px;
  height: 200px;
  top: -80px;
  right: -40px;
  animation: float-1 18s ease-in-out infinite;
}

.topic-hero .shape--2 {
  width: 100px;
  height: 100px;
  bottom: -40px;
  left: 10%;
  animation: float-2 14s ease-in-out infinite;
}

.topic-hero .shape--3 {
  width: 60px;
  height: 60px;
  top: 30%;
  right: 20%;
  animation: float-3 20s ease-in-out infinite;
}

@keyframes float-1 {
  0%, 100% { transform: translate(0, 0) scale(1); }
  50% { transform: translate(-15px, 15px) scale(1.05); }
}

@keyframes float-2 {
  0%, 100% { transform: translate(0, 0) rotate(0deg); }
  50% { transform: translate(20px, -15px) rotate(8deg); }
}

@keyframes float-3 {
  0%, 100% { transform: translate(0, 0) scale(1); opacity: 0.5; }
  50% { transform: translate(-25px, 10px) scale(1.1); opacity: 0.8; }
}

.topic-hero__content {
  position: relative;
  z-index: 1;
}

.topic-hero__badge {
  display: inline-block;
  padding: 0.375rem 0.75rem;
  background: rgba(255, 255, 255, 0.2);
  border-radius: 8px;
  font-size: 0.875rem;
  font-weight: 700;
  backdrop-filter: blur(5px);
  margin-bottom: 0.75rem;
}

.topic-hero__title {
  font-size: 1.75rem;
  font-weight: 700;
  margin: 0 0 0.25rem;
  line-height: 1.2;
  letter-spacing: -0.02em;
}

.topic-hero__subtitle {
  font-size: 1rem;
  margin: 0;
  opacity: 0.9;
}

.topic-hero__progress {
  margin-top: 1.5rem;
}

.topic-hero__progress-bar {
  height: 8px;
  background: rgba(255, 255, 255, 0.2);
  border-radius: 4px;
  overflow: hidden;
  margin-bottom: 1rem;
}

.topic-hero__progress-fill {
  height: 100%;
  background: white;
  border-radius: 4px;
  transition: width 0.5s ease;
}

.topic-hero__stats {
  display: flex;
  gap: 1.5rem;
}

.topic-hero__stat {
  display: flex;
  flex-direction: column;
}

.topic-hero__stat-value {
  font-size: 1.25rem;
  font-weight: 700;
  line-height: 1;
}

.topic-hero__stat-label {
  font-size: 0.75rem;
  opacity: 0.8;
  margin-top: 0.25rem;
}

.topic-hero__xp {
  position: absolute;
  top: 1.5rem;
  right: 1.5rem;
  display: flex;
  align-items: center;
  gap: 0.375rem;
  padding: 0.5rem 0.875rem;
  background: rgba(255, 255, 255, 0.2);
  border-radius: 8px;
  font-size: 0.9375rem;
  font-weight: 700;
  backdrop-filter: blur(5px);
  z-index: 1;
}

.topic-hero__xp svg {
  color: #fbbf24;
}

/* Grid */
.topic-grid {
  display: grid;
  grid-template-columns: 1fr 320px;
  gap: 1.5rem;
  align-items: start;
}

.topic-main {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

/* Topic Card */
.topic-card {
  background: var(--grammar-surface);
  border-radius: var(--grammar-radius);
  border: 1px solid var(--grammar-border);
  overflow: hidden;
}

.topic-card__header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1rem 1.25rem;
  border-bottom: 1px solid var(--grammar-border);
  background: var(--grammar-surface-alt);
}

.topic-card__header-left {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.topic-card__icon {
  width: 40px;
  height: 40px;
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff !important;
}

.topic-card__icon--theory {
  background: linear-gradient(135deg, var(--grammar-primary) 0%, var(--primary-500) 100%);
}

.topic-card__icon--practice {
  background: linear-gradient(135deg, var(--grammar-success) 0%, var(--success-600) 100%);
}

.topic-card__title {
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--grammar-text);
  margin: 0;
}

.topic-card__badge {
  display: inline-flex;
  align-items: center;
  gap: 0.25rem;
  padding: 0.375rem 0.625rem;
  border-radius: 6px;
  font-size: 0.75rem;
  font-weight: 600;
  background: var(--grammar-surface);
  color: var(--grammar-text-muted);
  border: 1px solid var(--grammar-border);
}

.topic-card__badge--success {
  background: rgba(34, 197, 94, 0.1);
  color: var(--success-600);
  border-color: transparent;
}

.topic-card__body {
  padding: 1.5rem;
}

.topic-card__empty {
  text-align: center;
  color: var(--grammar-text-muted);
  margin: 0;
}

.topic-card__action {
  margin-top: 1.5rem;
  text-align: center;
}

/* Theory Styles */
.theory-intro {
  font-size: 1rem;
  line-height: 1.7;
  color: var(--grammar-text);
  margin-bottom: 1.5rem;
  padding: 1rem;
  background: linear-gradient(135deg, rgba(var(--primary-600-rgb), 0.05) 0%, rgba(var(--primary-500-rgb), 0.05) 100%);
  border-radius: var(--grammar-radius-sm);
  border-left: 4px solid var(--grammar-primary);
}

.theory-section {
  margin-bottom: 2rem;
}

.theory-section:last-child {
  margin-bottom: 0;
}

.theory-section__title {
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--grammar-text);
  margin: 0 0 0.75rem;
}

.theory-section__desc {
  font-size: 0.9375rem;
  line-height: 1.6;
  color: var(--grammar-text-muted);
  margin: 0 0 1rem;
}

.theory-table-wrapper {
  overflow-x: auto;
  margin: 1rem 0;
}

.theory-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.875rem;
}

.theory-table th,
.theory-table td {
  padding: 0.75rem 1rem;
  text-align: left;
  border-bottom: 1px solid var(--grammar-border);
}

.theory-table th {
  background: var(--grammar-surface-alt);
  font-weight: 600;
  color: var(--grammar-text);
}

.theory-table__pronoun {
  font-weight: 600;
  color: var(--grammar-primary);
  white-space: nowrap;
}

.theory-table__form {
  font-weight: 600;
  color: var(--grammar-text);
}

.theory-table__translation {
  color: var(--grammar-text-muted);
  font-style: italic;
}

.theory-table--summary th:first-child {
  width: 80px;
}

.theory-rules {
  list-style: none;
  padding: 0;
  margin: 1rem 0;
}

.theory-rule {
  padding: 1rem;
  background: var(--grammar-surface-alt);
  border-radius: var(--grammar-radius-sm);
  margin-bottom: 0.75rem;
}

.theory-rule:last-child {
  margin-bottom: 0;
}

.theory-rule strong {
  display: block;
  color: var(--grammar-text);
  margin-bottom: 0.5rem;
}

.theory-rule__examples {
  padding-left: 1.25rem;
  margin: 0.5rem 0 0;
  color: var(--grammar-text-muted);
}

.theory-rule__examples li {
  margin-bottom: 0.25rem;
}

.theory-rule__note {
  margin-top: 0.5rem;
  padding: 0.5rem 0.75rem;
  background: rgba(var(--primary-600-rgb), 0.1);
  border-radius: 6px;
  font-size: 0.8125rem;
  color: var(--grammar-primary-dark);
}

.theory-alert {
  padding: 1rem;
  border-radius: var(--grammar-radius-sm);
  margin: 1.5rem 0;
}

.theory-alert--warning {
  background: rgba(245, 158, 11, 0.1);
  border: 1px solid rgba(245, 158, 11, 0.2);
}

.theory-alert--danger {
  background: rgba(239, 68, 68, 0.1);
  border: 1px solid rgba(239, 68, 68, 0.2);
}

.theory-alert__header {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-weight: 700;
  margin-bottom: 0.75rem;
}

.theory-alert--warning .theory-alert__header {
  color: #d97706;
}

.theory-alert--danger .theory-alert__header {
  color: #dc2626;
}

.theory-alert ul {
  padding-left: 1.25rem;
  margin: 0;
}

.theory-alert li {
  margin-bottom: 0.375rem;
  color: var(--grammar-text);
}

.theory-mistake {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 0.5rem;
  flex-wrap: wrap;
}

.theory-mistake__wrong {
  padding: 0.375rem 0.75rem;
  background: rgba(239, 68, 68, 0.15);
  border-radius: 6px;
  color: #dc2626;
  text-decoration: line-through;
  font-weight: 500;
}

.theory-mistake__correct {
  padding: 0.375rem 0.75rem;
  background: rgba(34, 197, 94, 0.15);
  border-radius: 6px;
  color: var(--success-600);
  font-weight: 500;
}

.theory-mistake__explain {
  font-size: 0.8125rem;
  color: var(--grammar-text-muted);
  margin: 0 0 1rem;
}

.theory-summary {
  margin-top: 1.5rem;
  padding: 1rem;
  background: linear-gradient(135deg, rgba(34, 197, 94, 0.05) 0%, rgba(16, 163, 127, 0.05) 100%);
  border-radius: var(--grammar-radius-sm);
  border: 1px solid rgba(34, 197, 94, 0.2);
}

.theory-summary__header {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-weight: 700;
  color: var(--success-600);
  margin-bottom: 1rem;
}

/* Practice Start */
.practice-start {
  text-align: center;
  padding: 2rem 1rem;
}

.practice-start__icon {
  width: 72px;
  height: 72px;
  margin: 0 auto 1.25rem;
  background: linear-gradient(135deg, rgba(34, 197, 94, 0.1) 0%, rgba(16, 185, 129, 0.1) 100%);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--grammar-success);
}

.practice-start__title {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--grammar-text);
  margin: 0 0 0.5rem;
}

.practice-start__desc {
  font-size: 0.9375rem;
  color: var(--grammar-text);
  margin: 0 0 0.25rem;
}

.practice-start__note {
  font-size: 0.8125rem;
  color: var(--grammar-text-muted);
  margin: 0 0 1.5rem;
}

/* Sidebar */
.topic-sidebar {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.sidebar-card {
  background: var(--grammar-surface);
  border-radius: var(--grammar-radius);
  border: 1px solid var(--grammar-border);
  overflow: hidden;
}

.sidebar-card__header {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 1rem;
  border-bottom: 1px solid var(--grammar-border);
  background: var(--grammar-surface-alt);
}

.sidebar-card__icon {
  width: 36px;
  height: 36px;
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff !important;
}

.sidebar-card__icon--progress {
  background: linear-gradient(135deg, var(--grammar-primary) 0%, var(--primary-500) 100%);
}

.sidebar-card__icon--info {
  background: linear-gradient(135deg, #3b82f6 0%, #1d4ed8 100%);
}

.sidebar-card__title {
  font-size: 0.9375rem;
  font-weight: 700;
  color: var(--grammar-text);
  margin: 0;
}

.sidebar-card__body {
  padding: 1rem;
}

/* Progress */
.progress-mastery {
  margin-bottom: 1rem;
}

.progress-mastery__header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 0.5rem;
  font-size: 0.875rem;
  color: var(--grammar-text);
}

.progress-mastery__bar {
  height: 8px;
  background: rgba(var(--primary-600-rgb), 0.15);
  border-radius: 4px;
  overflow: hidden;
}

.progress-mastery__fill {
  height: 100%;
  background: linear-gradient(90deg, var(--grammar-primary) 0%, var(--primary-500) 100%);
  border-radius: 4px;
  transition: width 0.5s ease;
}

.progress-stats {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.75rem;
  margin-bottom: 1rem;
}

.progress-stat {
  padding: 0.75rem;
  border-radius: var(--grammar-radius-sm);
  text-align: center;
}

.progress-stat--success {
  background: rgba(34, 197, 94, 0.1);
}

.progress-stat--primary {
  background: rgba(var(--primary-600-rgb), 0.1);
}

.progress-stat__value {
  display: block;
  font-size: 1.25rem;
  font-weight: 700;
  line-height: 1;
}

.progress-stat--success .progress-stat__value {
  color: var(--grammar-success);
}

.progress-stat--primary .progress-stat__value {
  color: var(--grammar-primary);
}

.progress-stat__label {
  display: block;
  font-size: 0.6875rem;
  color: var(--grammar-text-muted);
  margin-top: 0.25rem;
}

.progress-accuracy {
  text-align: center;
  padding: 0.75rem;
  background: var(--grammar-surface-alt);
  border-radius: var(--grammar-radius-sm);
  margin-bottom: 1rem;
}

.progress-accuracy__value {
  font-size: 1.5rem;
  font-weight: 700;
}

.progress-accuracy__value--high {
  color: var(--grammar-success);
}

.progress-accuracy__value--medium {
  color: var(--grammar-warning);
}

.progress-accuracy__value--low {
  color: var(--grammar-danger);
}

.progress-accuracy__label {
  display: block;
  font-size: 0.75rem;
  color: var(--grammar-text-muted);
  margin-top: 0.125rem;
}

.progress-review {
  padding: 0.75rem;
  background: rgba(var(--info-500-rgb), 0.1);
  border-radius: var(--grammar-radius-sm);
  text-align: center;
}

.progress-review__label {
  display: block;
  font-size: 0.75rem;
  color: var(--grammar-text-muted);
  margin-bottom: 0.25rem;
}

.progress-review__date {
  font-size: 0.9375rem;
  font-weight: 600;
  color: #2563eb;
}

/* Info List */
.info-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.info-item {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.75rem 0;
  border-bottom: 1px solid var(--grammar-border);
}

.info-item:last-child {
  border-bottom: none;
}

.info-item__icon {
  width: 36px;
  height: 36px;
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.info-item__icon--level {
  background: rgba(var(--primary-600-rgb), 0.1);
  color: var(--grammar-primary);
}

.info-item__icon--time {
  background: rgba(var(--info-500-rgb), 0.1);
  color: #2563eb;
}

.info-item__icon--difficulty {
  background: rgba(245, 158, 11, 0.1);
  color: #d97706;
}

.info-item__icon--exercises {
  background: rgba(34, 197, 94, 0.1);
  color: var(--success-600);
}

.info-item__content {
  flex: 1;
}

.info-item__label {
  display: block;
  font-size: 0.75rem;
  color: var(--grammar-text-muted);
}

.info-item__value {
  display: flex;
  align-items: center;
  gap: 0.125rem;
  font-size: 0.9375rem;
  color: var(--grammar-text);
}

/* Buttons */
.topic-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  font-family: var(--grammar-font);
  font-size: 0.9375rem;
  font-weight: 600;
  border: none;
  border-radius: var(--grammar-radius-sm);
  cursor: pointer;
  text-decoration: none;
  transition: all 0.2s ease;
}

.topic-btn--large {
  padding: 1rem 2rem;
  font-size: 1rem;
}

.topic-btn--primary {
  background: linear-gradient(135deg, var(--primary-700) 0%, var(--primary-600) 100%);
  color: #fff !important;
}

.topic-btn--primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(var(--primary-600-rgb), 0.4);
  color: #fff !important;
}

.topic-btn--success {
  background: linear-gradient(135deg, var(--grammar-success) 0%, var(--success-600) 100%);
  color: #fff !important;
}

.topic-btn--success:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(34, 197, 94, 0.4);
  color: #fff !important;
}

.topic-btn--secondary {
  background: var(--grammar-surface-alt);
  color: var(--grammar-text);
  border: 1px solid var(--grammar-border);
}

.topic-btn--secondary:hover {
  background: var(--grammar-surface);
  color: var(--grammar-text);
}

.topic-btn--outline {
  background: transparent;
  color: var(--grammar-primary);
  border: 2px solid var(--grammar-primary);
}

.topic-btn--outline:hover {
  background: var(--grammar-primary);
  color: #fff !important;
}

/* XP Notification */
.xp-notification {
  position: fixed;
  top: 20px;
  right: 20px;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 1.25rem;
  background: linear-gradient(135deg, var(--warning-500) 0%, #d97706 100%);
  color: #fff !important;
  border-radius: 10px;
  font-weight: 600;
  box-shadow: 0 4px 12px rgba(245, 158, 11, 0.4);
  animation: slideIn 0.3s ease, fadeOut 0.3s ease 2.7s forwards;
  z-index: 9999;
}

@keyframes slideIn {
  from { opacity: 0; transform: translateX(100px); }
  to { opacity: 1; transform: translateX(0); }
}

@keyframes fadeOut {
  to { opacity: 0; transform: translateY(-20px); }
}

/* Animations */
@keyframes slideUp {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}

.topic-hero { animation: slideUp 0.4s ease-out; }
.topic-grid { animation: slideUp 0.4s ease-out 0.1s both; }

/* Responsive */
@media (max-width: 900px) {
  .topic-grid {
    grid-template-columns: 1fr;
  }

  .topic-sidebar {
    order: -1;
  }
}

@media (max-width: 640px) {
  .grammar-page {
    padding: 0 0.75rem 2rem;
  }

  .topic-hero {
    padding: 1.5rem;
  }

  .topic-hero__title {
    font-size: 1.375rem;
  }

  .topic-hero__xp {
    position: static;
    display: inline-flex;
    margin-top: 1rem;
  }

  .topic-hero__stats {
    flex-wrap: wrap;
    gap: 1rem;
  }

  .topic-card__header {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.75rem;
  }


}

/* ============================================
   Previous/Next Topic Navigation
   ============================================ */

.topic-nav-adjacent {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 1.5rem;
}

.topic-nav-adjacent__link {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.625rem 1rem;
  background: var(--grammar-surface);
  border: 1px solid var(--grammar-border);
  border-radius: 10px;
  text-decoration: none;
  color: var(--grammar-text);
  transition: all 0.2s;
  max-width: 48%;
}

.topic-nav-adjacent__link:hover {
  border-color: var(--grammar-primary);
  box-shadow: 0 2px 8px rgba(var(--primary-600-rgb), 0.1);
}

.topic-nav-adjacent__link--next {
  margin-left: auto;
  text-align: right;
}

.topic-nav-adjacent__link svg {
  color: var(--grammar-primary);
  flex-shrink: 0;
}

.topic-nav-adjacent__text {
  min-width: 0;
}

.topic-nav-adjacent__label {
  display: block;
  font-size: 0.7rem;
  font-weight: 600;
  color: var(--grammar-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.topic-nav-adjacent__title {
  display: block;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--grammar-text);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

/* Jump to exercises link */
.topic-card__jump-link {
  display: inline-flex;
  align-items: center;
  gap: 0.25rem;
  font-size: 0.8rem;
  color: var(--grammar-primary);
  text-decoration: none;
  font-weight: 500;
  margin-left: 0.75rem;
  transition: all 0.2s;
}

.topic-card__jump-link:hover {
  text-decoration: underline;
  color: var(--grammar-primary-dark);
}

@media (max-width: 600px) {
  .topic-nav-adjacent {
    flex-direction: column;
    gap: 0.5rem;
  }

  .topic-nav-adjacent__link {
    max-width: 100%;
  }

  .topic-nav-adjacent__link--next {
    text-align: left;
    flex-direction: row-reverse;
  }
}

.topic-related-card:hover { border-color: var(--grammar-primary) !important; transform: translateY(-2px); }
.topic-related-word:hover { border-color: var(--grammar-primary) !important; }
.topic-related-cta:hover { border-color: var(--grammar-primary) !important; }