/* ==========================================================================
   OPEN TEXTBOOKS - Component Styles
   Header, Footer, Navigation, and shared components
   ========================================================================== */

/* ==========================================================================
   Site Header - Two Row Navigation
   ========================================================================== */
.site-header {
  position: sticky;
  top: 0;
  z-index: var(--z-sticky);
  background: var(--color-bg-elevated);
  border-bottom: 1px solid var(--color-border);
}

/* Row 1: Utility Navigation */
.header-utility {
  background: var(--slate-800);
  color: var(--slate-200);
}

.header-utility__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-2) var(--space-4);
  max-width: var(--max-width-wide);
  margin: 0 auto;
}

.header-utility__brand {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.header-utility__logo {
  font-family: var(--font-display);
  font-size: var(--text-lg);
  font-weight: 700;
  color: white;
  text-decoration: none;
}

.header-utility__logo:hover {
  color: var(--amber-300);
}

.header-utility__tagline {
  font-size: var(--text-xs);
  color: var(--slate-400);
  display: none;
}

@media (min-width: 768px) {
  .header-utility__tagline {
    display: block;
  }
}

.utility-nav {
  display: flex;
  align-items: center;
  gap: var(--space-1);
  list-style: none;
  padding: 0;
  margin: 0;
}

.utility-nav__item {
  margin: 0;
}

.utility-nav__link {
  display: block;
  padding: var(--space-2) var(--space-3);
  font-size: var(--text-sm);
  color: var(--slate-300);
  text-decoration: none;
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
}

.utility-nav__link:hover {
  color: white;
  background: var(--slate-700);
}

.utility-nav__link:focus-visible {
  outline: 2px solid var(--amber-400);
  outline-offset: 2px;
}

.utility-nav__link[aria-current="page"],
.utility-nav__link--active {
  color: white;
  background: var(--slate-700);
}

/* Row 2: Grade Navigation */
.header-grades {
  background: var(--color-bg-elevated);
  border-top: 1px solid var(--slate-700);
}

.header-grades__inner {
  display: flex;
  align-items: center;
  max-width: var(--max-width-wide);
  margin: 0 auto;
  padding: 0 var(--space-4);
}

.header-grades__label {
  flex-shrink: 0;
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--color-text-muted);
  padding: var(--space-3) var(--space-4) var(--space-3) 0;
  border-right: 1px solid var(--color-border);
  display: none;
}

@media (min-width: 640px) {
  .header-grades__label {
    display: block;
  }
}

/* Grade navigation scrollable container */
.grade-nav-wrapper {
  flex: 1;
  overflow-x: auto;
  overflow-y: hidden;
  scrollbar-width: thin;
  scrollbar-color: var(--slate-300) transparent;
  -webkit-overflow-scrolling: touch;
}

.grade-nav-wrapper::-webkit-scrollbar {
  height: 4px;
}

.grade-nav-wrapper::-webkit-scrollbar-track {
  background: transparent;
}

.grade-nav-wrapper::-webkit-scrollbar-thumb {
  background: var(--slate-300);
  border-radius: var(--radius-full);
}

.grade-nav {
  display: flex;
  align-items: center;
  gap: var(--space-1);
  padding: var(--space-2) var(--space-2);
  list-style: none;
  margin: 0;
  min-width: max-content;
}

.grade-nav__item {
  margin: 0;
}

.grade-nav__link {
  display: flex;
  align-items: center;
  justify-content: center;
  min-width: 44px;
  height: 44px;
  padding: var(--space-2) var(--space-3);
  font-size: var(--text-base);
  font-weight: 600;
  color: var(--slate-600);
  text-decoration: none;
  border: 2px solid transparent;
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
}

.grade-nav__link:hover {
  color: var(--amber-700);
  background: var(--amber-50);
  border-color: var(--amber-200);
}

.grade-nav__link:focus-visible {
  outline: 2px solid var(--color-focus);
  outline-offset: 2px;
}

.grade-nav__link[aria-current="page"],
.grade-nav__link--active {
  color: var(--amber-800);
  background: var(--amber-100);
  border-color: var(--amber-300);
}

/* Kindergarten special styling */
.grade-nav__link[data-grade="k"] {
  font-size: var(--text-sm);
}

/* Mobile Menu Toggle (for collapsible behavior) */
.mobile-menu-toggle {
  display: none;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  padding: 0;
  background: transparent;
  border: none;
  color: var(--slate-300);
  cursor: pointer;
  border-radius: var(--radius-sm);
}

.mobile-menu-toggle:hover {
  background: var(--slate-700);
  color: white;
}

.mobile-menu-toggle:focus-visible {
  outline: 2px solid var(--amber-400);
  outline-offset: 2px;
}

.mobile-menu-toggle__icon {
  width: 24px;
  height: 24px;
}

/* Show mobile toggle on small screens */
@media (max-width: 639px) {
  .mobile-menu-toggle {
    display: flex;
  }
  
  .header-grades {
    position: relative;
  }
  
  .header-grades[data-collapsed="true"] .grade-nav-wrapper {
    display: none;
  }
  
  .header-grades[data-collapsed="false"] .grade-nav-wrapper {
    display: block;
  }
}

/* Scroll indicators for grade nav */
.header-grades__inner {
  position: relative;
}

.header-grades__inner::before,
.header-grades__inner::after {
  content: '';
  position: absolute;
  top: 0;
  bottom: 0;
  width: 40px;
  pointer-events: none;
  opacity: 0;
  transition: opacity var(--transition-fast);
  z-index: 1;
}

.header-grades__inner::before {
  left: 100px;
  background: linear-gradient(to right, var(--color-bg-elevated), transparent);
}

.header-grades__inner::after {
  right: 0;
  background: linear-gradient(to left, var(--color-bg-elevated), transparent);
}

.header-grades__inner[data-scroll-start="false"]::before {
  opacity: 1;
}

.header-grades__inner[data-scroll-end="false"]::after {
  opacity: 1;
}

/* ==========================================================================
   Site Footer
   ========================================================================== */
.site-footer {
  background: var(--slate-900);
  color: var(--slate-300);
  margin-top: auto;
}

.site-footer__main {
  padding: var(--space-12) var(--space-4);
  max-width: var(--max-width-wide);
  margin: 0 auto;
}

.site-footer__grid {
  display: grid;
  gap: var(--space-8);
  grid-template-columns: 1fr;
}

@media (min-width: 768px) {
  .site-footer__grid {
    grid-template-columns: 2fr 1fr 1fr;
  }
}

.site-footer__brand {
  max-width: 320px;
}

.site-footer__logo {
  font-family: var(--font-display);
  font-size: var(--text-xl);
  font-weight: 700;
  color: white;
  text-decoration: none;
  display: inline-block;
  margin-bottom: var(--space-3);
}

.site-footer__logo:hover {
  color: var(--amber-300);
}

.site-footer__description {
  font-size: var(--text-sm);
  color: var(--slate-400);
  line-height: var(--leading-relaxed);
  margin: 0;
}

.site-footer__section-title {
  font-family: var(--font-body);
  font-size: var(--text-sm);
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--slate-500);
  margin-bottom: var(--space-4);
}

.footer-nav {
  list-style: none;
  padding: 0;
  margin: 0;
}

.footer-nav__item {
  margin-bottom: var(--space-2);
}

.footer-nav__link {
  font-size: var(--text-sm);
  color: var(--slate-300);
  text-decoration: none;
  transition: color var(--transition-fast);
}

.footer-nav__link:hover {
  color: white;
  text-decoration: underline;
}

.site-footer__bottom {
  border-top: 1px solid var(--slate-800);
  padding: var(--space-6) var(--space-4);
}

.site-footer__bottom-inner {
  max-width: var(--max-width-wide);
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  font-size: var(--text-sm);
  color: var(--slate-500);
}

@media (min-width: 768px) {
  .site-footer__bottom-inner {
    flex-direction: row;
    justify-content: space-between;
    align-items: center;
  }
}

.site-footer__copyright {
  margin: 0;
}

.site-footer__license {
  margin: 0;
}

/* ==========================================================================
   Skip Link (Accessibility)
   ========================================================================== */
.skip-link {
  position: absolute;
  top: -100%;
  left: var(--space-4);
  padding: var(--space-3) var(--space-4);
  background: var(--amber-500);
  color: white;
  font-weight: 600;
  text-decoration: none;
  border-radius: var(--radius-md);
  z-index: var(--z-modal);
  transition: top var(--transition-fast);
}

.skip-link:focus {
  top: var(--space-4);
}

/* ==========================================================================
   Breadcrumbs
   ========================================================================== */
.breadcrumbs {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--space-2);
  padding: var(--space-4) 0;
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  list-style: none;
  margin: 0;
}

.breadcrumbs__item {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  margin: 0;
}

.breadcrumbs__item:not(:last-child)::after {
  content: '/';
  color: var(--slate-300);
}

.breadcrumbs__link {
  color: var(--color-text-muted);
  text-decoration: none;
}

.breadcrumbs__link:hover {
  color: var(--color-link);
  text-decoration: underline;
}

.breadcrumbs__current {
  color: var(--color-text);
  font-weight: 500;
}

/* ==========================================================================
   Subject Cards (for Grade Landing Pages)
   ========================================================================== */
.subject-grid {
  display: grid;
  gap: var(--space-6);
  grid-template-columns: 1fr;
}

@media (min-width: 640px) {
  .subject-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 1024px) {
  .subject-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

.subject-card {
  display: flex;
  flex-direction: column;
  background: var(--color-bg-elevated);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  text-decoration: none;
  color: inherit;
  transition: all var(--transition-base);
}

.subject-card:hover {
  border-color: var(--amber-300);
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

.subject-card:focus-visible {
  outline: 2px solid var(--color-focus);
  outline-offset: 2px;
}

.subject-card__icon {
  font-size: var(--text-4xl);
  margin-bottom: var(--space-3);
}

.subject-card__title {
  font-family: var(--font-display);
  font-size: var(--text-xl);
  font-weight: 700;
  color: var(--color-heading);
  margin-bottom: var(--space-2);
}

.subject-card__description {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  margin-bottom: var(--space-4);
  flex: 1;
}

.subject-card__meta {
  font-size: var(--text-xs);
  color: var(--color-text-subtle);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

/* ==========================================================================
   Chapter/Lesson Navigation (Table of Contents)
   ========================================================================== */
.toc {
  background: var(--color-bg-alt);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
}

.toc__title {
  font-family: var(--font-display);
  font-size: var(--text-lg);
  margin-bottom: var(--space-4);
}

.toc__list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.toc__chapter {
  margin-bottom: var(--space-4);
}

.toc__chapter:last-child {
  margin-bottom: 0;
}

.toc__chapter-title {
  font-weight: 600;
  color: var(--color-heading);
  margin-bottom: var(--space-2);
}

.toc__lessons {
  list-style: none;
  padding-left: var(--space-4);
  margin: 0;
  border-left: 2px solid var(--color-border);
}

.toc__lesson {
  margin-bottom: var(--space-1);
}

.toc__lesson-link {
  display: block;
  padding: var(--space-2) var(--space-3);
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  text-decoration: none;
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
}

.toc__lesson-link:hover {
  color: var(--amber-700);
  background: var(--amber-50);
}

.toc__lesson-link[aria-current="page"] {
  color: var(--amber-800);
  background: var(--amber-100);
  font-weight: 500;
}

/* ==========================================================================
   Lesson Content Layout
   ========================================================================== */
.lesson-layout {
  display: grid;
  gap: var(--space-8);
  grid-template-columns: 1fr;
}

@media (min-width: 1024px) {
  .lesson-layout {
    grid-template-columns: 280px 1fr;
  }
}

.lesson-sidebar {
  position: sticky;
  top: calc(120px + var(--space-4));
  align-self: start;
  display: none;
}

@media (min-width: 1024px) {
  .lesson-sidebar {
    display: block;
  }
}

.lesson-content {
  max-width: var(--max-width-prose);
}

.lesson-content h1 {
  margin-bottom: var(--space-4);
}

.lesson-content__meta {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
  margin-bottom: var(--space-6);
  padding-bottom: var(--space-6);
  border-bottom: 1px solid var(--color-border);
}

/* Lesson Navigation (Previous/Next) */
.lesson-nav {
  display: flex;
  justify-content: space-between;
  gap: var(--space-4);
  margin-top: var(--space-12);
  padding-top: var(--space-8);
  border-top: 1px solid var(--color-border);
}

.lesson-nav__link {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
  padding: var(--space-4);
  text-decoration: none;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
  max-width: 50%;
}

.lesson-nav__link:hover {
  border-color: var(--amber-300);
  background: var(--amber-50);
}

.lesson-nav__link--prev {
  align-items: flex-start;
}

.lesson-nav__link--next {
  align-items: flex-end;
  margin-left: auto;
}

.lesson-nav__label {
  font-size: var(--text-xs);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-text-muted);
}

.lesson-nav__title {
  font-weight: 600;
  color: var(--color-heading);
}

/* ==========================================================================
   Alert / Notice Boxes
   ========================================================================== */
.notice {
  padding: var(--space-4) var(--space-5);
  border-radius: var(--radius-md);
  margin-bottom: var(--space-6);
  border-left: 4px solid;
}

.notice--info {
  background: var(--slate-50);
  border-color: var(--sky-500);
}

.notice--success {
  background: var(--sage-50);
  border-color: var(--sage-500);
}

.notice--warning {
  background: var(--amber-50);
  border-color: var(--amber-500);
}

.notice__title {
  font-weight: 600;
  margin-bottom: var(--space-2);
}

.notice p:last-child {
  margin-bottom: 0;
}

/* ==========================================================================
   NEW TWO-ROW HEADER (Build Script Compatible)
   ========================================================================== */

.header-row-1 {
  background: var(--slate-800);
  color: var(--slate-200);
}

.header-row-1 .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-2) var(--space-4);
  max-width: var(--max-width-wide);
  margin: 0 auto;
}

.site-logo {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  text-decoration: none;
  color: white;
}

.logo-icon {
  font-size: var(--text-xl);
}

.logo-text {
  font-family: var(--font-display);
  font-size: var(--text-lg);
  font-weight: 700;
}

.site-logo:hover {
  color: var(--amber-300);
}

.nav-primary {
  display: flex;
  align-items: center;
  gap: var(--space-1);
}

.nav-primary .nav-link {
  display: block;
  padding: var(--space-2) var(--space-3);
  font-size: var(--text-sm);
  color: var(--slate-300);
  text-decoration: none;
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
}

.nav-primary .nav-link:hover {
  color: white;
  background: var(--slate-700);
}

.header-row-2 {
  background: var(--color-bg-elevated);
  border-top: 1px solid var(--slate-700);
}

.header-row-2 .container {
  max-width: var(--max-width-wide);
  margin: 0 auto;
  padding: 0 var(--space-4);
}

.nav-grades {
  overflow-x: auto;
  overflow-y: hidden;
  scrollbar-width: thin;
  scrollbar-color: var(--slate-300) transparent;
  -webkit-overflow-scrolling: touch;
}

.grades-scroll {
  display: flex;
  align-items: center;
  gap: var(--space-1);
  padding: var(--space-2) 0;
  min-width: max-content;
}

.grades-scroll a {
  display: flex;
  align-items: center;
  justify-content: center;
  min-width: 44px;
  height: 44px;
  padding: var(--space-2) var(--space-3);
  font-size: var(--text-base);
  font-weight: 600;
  color: var(--slate-600);
  text-decoration: none;
  border: 2px solid transparent;
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
}

.grades-scroll a:hover {
  color: var(--amber-700);
  background: var(--amber-50);
  border-color: var(--amber-200);
}

.grades-scroll a.active {
  color: var(--amber-800);
  background: var(--amber-100);
  border-color: var(--amber-300);
}

/* ==========================================================================
   Breadcrumb Navigation
   ========================================================================== */

.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-4) 0;
  font-size: var(--text-sm);
  color: var(--color-text-muted);
}

.breadcrumb a {
  color: var(--color-link);
  text-decoration: none;
}

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

.breadcrumb-sep {
  color: var(--color-text-subtle);
}

.breadcrumb-current {
  color: var(--color-text);
  font-weight: 500;
}

/* ==========================================================================
   Page Header
   ========================================================================== */

.page-header {
  padding: var(--space-6) 0;
  margin-bottom: var(--space-8);
  border-bottom: 1px solid var(--color-border);
}

.page-header h1 {
  font-family: var(--font-display);
  font-size: var(--text-4xl);
  color: var(--color-heading);
  margin: 0 0 var(--space-4);
}

.page-header .lead {
  font-size: var(--text-lg);
  color: var(--color-text-muted);
  line-height: var(--leading-relaxed);
  margin: 0;
}

.page-header .page-meta {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: var(--space-2);
}

/* Page header with up button layout */
.page-header-content {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: var(--space-4);
}

.page-header-text {
  flex: 1;
}

.up-button {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-4);
  background: var(--color-bg-elevated);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  color: var(--color-text);
  font-size: var(--text-sm);
  font-weight: 500;
  text-decoration: none;
  transition: all 0.2s ease;
  flex-shrink: 0;
}

.up-button:hover {
  background: var(--amber-50);
  border-color: var(--amber-300);
  color: var(--amber-700);
}

.up-button svg {
  width: 16px;
  height: 16px;
  min-width: 16px;
  max-width: 16px;
  min-height: 16px;
  max-height: 16px;
  flex-shrink: 0;
}

[data-theme="dark"] .up-button {
  background: var(--color-bg-elevated);
  border-color: var(--color-border);
  color: var(--color-text);
}

[data-theme="dark"] .up-button:hover {
  background: var(--color-surface);
  border-color: var(--amber-500);
  color: var(--amber-400);
}

.subject-header {
  display: flex;
  align-items: flex-start;
  gap: var(--space-6);
}

.subject-icon-large {
  font-size: 4rem;
  line-height: 1;
}

/* ==========================================================================
   Subject Cards
   ========================================================================== */

.subjects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: var(--space-6);
}

.subject-card {
  display: block;
  padding: var(--space-6);
  background: var(--color-bg-elevated);
  border: 2px solid var(--color-border);
  border-radius: var(--radius-lg);
  text-decoration: none;
  transition: all var(--transition-fast);
}

.subject-card:hover {
  border-color: var(--subject-color, var(--amber-400));
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

.subject-card .subject-icon {
  display: block;
  font-size: 2.5rem;
  margin-bottom: var(--space-3);
}

.subject-card .subject-name {
  font-family: var(--font-display);
  font-size: var(--text-xl);
  color: var(--color-heading);
  margin: 0 0 var(--space-2);
}

.subject-card .subject-desc {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  margin: 0;
}

/* ==========================================================================
   Unit Cards
   ========================================================================== */

.units-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: var(--space-4);
}

.unit-card {
  display: block;
  padding: var(--space-5);
  background: var(--color-bg-elevated);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  text-decoration: none;
  transition: all var(--transition-fast);
}

.unit-card:hover {
  border-color: var(--amber-400);
  box-shadow: var(--shadow-sm);
}

.unit-card .unit-title {
  font-size: var(--text-lg);
  color: var(--color-heading);
  margin: 0 0 var(--space-2);
}

.unit-card .unit-desc {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  margin: 0 0 var(--space-3);
}

.unit-card .unit-meta {
  font-size: var(--text-xs);
  color: var(--color-text-subtle);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

/* ==========================================================================
   Lesson List
   ========================================================================== */

.lessons-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.lesson-card {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  padding: var(--space-4);
  background: var(--color-bg-elevated);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  text-decoration: none;
  transition: all var(--transition-fast);
}

.lesson-card:hover {
  border-color: var(--amber-400);
  background: var(--amber-50);
}

.lesson-card .lesson-number {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  background: var(--slate-100);
  color: var(--slate-600);
  font-weight: 600;
  border-radius: var(--radius-full);
  flex-shrink: 0;
}

.lesson-card .lesson-info {
  flex: 1;
}

.lesson-card .lesson-title {
  font-size: var(--text-base);
  color: var(--color-heading);
  margin: 0 0 var(--space-1);
}

.lesson-card .lesson-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
}

.lesson-card .tag {
  font-size: var(--text-xs);
  padding: var(--space-1) var(--space-2);
  border-radius: var(--radius-sm);
  background: var(--slate-100);
  color: var(--slate-600);
}

.lesson-card .tag.sat {
  background: var(--sky-500);
  background: rgba(14, 165, 233, 0.15);
  color: var(--sky-600);
}

.lesson-card .tag.act {
  background: rgba(139, 92, 246, 0.15);
  color: #7c3aed;
}

/* ==========================================================================
   Lesson Page
   ========================================================================== */

.lesson-page .lesson-content {
  max-width: 800px;
}

.lesson-header {
  margin-bottom: var(--space-8);
  padding-bottom: var(--space-6);
  border-bottom: 1px solid var(--color-border);
}

.lesson-meta-box {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-4);
  padding: var(--space-4);
  background: var(--slate-50);
  border-radius: var(--radius-md);
  margin-bottom: var(--space-4);
  font-size: var(--text-sm);
}

.lesson-meta-box .meta-item {
  color: var(--color-text-muted);
}

.lesson-meta-box .meta-item strong {
  color: var(--color-text);
}

.lesson-section {
  margin-bottom: var(--space-10);
}

.lesson-section h2 {
  font-family: var(--font-display);
  font-size: var(--text-2xl);
  color: var(--color-heading);
  margin: 0 0 var(--space-4);
}

.content-placeholder {
  padding: var(--space-6);
  background: var(--slate-50);
  border: 2px dashed var(--slate-200);
  border-radius: var(--radius-md);
  text-align: center;
  color: var(--color-text-muted);
}

.lesson-navigation {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: var(--space-4);
  padding: var(--space-6) 0;
  border-top: 1px solid var(--color-border);
  margin-top: var(--space-8);
}

.lesson-navigation a {
  color: var(--color-link);
  text-decoration: none;
  font-weight: 500;
}

.lesson-navigation a:hover {
  text-decoration: underline;
}

.lesson-navigation .nav-unit {
  padding: var(--space-2) var(--space-4);
  background: var(--slate-100);
  border-radius: var(--radius-md);
}

/* ==========================================================================
   Skills List
   ========================================================================== */

.skills-overview {
  margin-bottom: var(--space-8);
}

.skills-list {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  list-style: none;
  padding: 0;
  margin: var(--space-4) 0 0;
}

.skills-list li {
  padding: var(--space-2) var(--space-4);
  background: var(--sage-50);
  color: var(--sage-700);
  border-radius: var(--radius-full);
  font-size: var(--text-sm);
  font-weight: 500;
}

/* ==========================================================================
   What You'll Learn
   ========================================================================== */

.what-youll-learn {
  margin-bottom: var(--space-8);
}

.what-youll-learn ul {
  margin: var(--space-4) 0 0;
  padding-left: var(--space-6);
}

.what-youll-learn li {
  margin-bottom: var(--space-2);
  color: var(--color-text);
}

/* ==========================================================================
   Alignment Box (SAT/ACT tags)
   ========================================================================== */

.alignment-box {
  padding: var(--space-5);
  background: #f8fafc;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  margin-bottom: var(--space-8);
}

.alignment-box h3 {
  font-size: var(--text-base);
  color: var(--amber-600);
  font-weight: 600;
  margin: 0 0 var(--space-3);
}

.alignment-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-4);
}

.tag-group {
  display: flex;
  align-items: baseline;
  gap: var(--space-2);
}

.tag-label {
  font-weight: 600;
  color: var(--color-text);
  font-size: var(--text-sm);
}

.tag-values {
  color: var(--color-text-muted);
  font-size: var(--text-sm);
}

/* ==========================================================================
   Static Pages
   ========================================================================== */

.static-page {
  max-width: 700px;
  padding: var(--space-8) 0;
}

.static-page h1 {
  font-family: var(--font-display);
  font-size: var(--text-4xl);
  color: var(--color-heading);
  margin: 0 0 var(--space-6);
}

.static-page h2 {
  font-family: var(--font-display);
  font-size: var(--text-2xl);
  color: var(--color-heading);
  margin: var(--space-8) 0 var(--space-4);
}

.static-page h2:first-of-type {
  margin-top: 0;
}

.static-page p {
  margin: 0 0 var(--space-4);
  line-height: var(--leading-relaxed);
}

.static-page .lead {
  font-size: var(--text-lg);
  color: var(--color-text-muted);
  margin-bottom: var(--space-6);
}

.static-page ul {
  margin: 0 0 var(--space-4);
  padding-left: var(--space-6);
}

.static-page li {
  margin-bottom: var(--space-2);
}

.login-note {
  padding: var(--space-4);
  background: var(--amber-50);
  border-left: 4px solid var(--amber-400);
  border-radius: var(--radius-sm);
  margin: var(--space-6) 0;
}

.login-placeholder {
  padding: var(--space-8);
  background: var(--slate-50);
  border: 2px dashed var(--slate-200);
  border-radius: var(--radius-md);
  text-align: center;
  color: var(--color-text-muted);
}

/* ==========================================================================
   Error Page
   ========================================================================== */

.error-page {
  text-align: center;
  padding: var(--space-16) 0;
}

.error-page h1 {
  font-family: var(--font-display);
  font-size: 8rem;
  color: var(--slate-200);
  margin: 0;
  line-height: 1;
}

.error-page .error-message {
  font-size: var(--text-2xl);
  color: var(--color-heading);
  margin: var(--space-4) 0;
}

.error-page p {
  color: var(--color-text-muted);
  margin-bottom: var(--space-6);
}

.btn {
  display: inline-block;
  padding: var(--space-3) var(--space-6);
  font-weight: 600;
  text-decoration: none;
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
}

.btn-primary {
  background: var(--amber-600);
  color: white;
}

.btn-primary:hover {
  background: var(--amber-700);
}

/* ==========================================================================
   Grade Cards (Home Page)
   ========================================================================== */

.grades-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: var(--space-4);
}

.grade-card {
  display: block;
  padding: var(--space-5);
  background: var(--color-bg-elevated);
  border: 2px solid var(--color-border);
  border-radius: var(--radius-lg);
  text-decoration: none;
  transition: all var(--transition-fast);
}

.grade-card:hover {
  border-color: var(--amber-400);
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

.grade-card-header {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  margin-bottom: var(--space-3);
}

.grade-badge {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  background: var(--amber-100);
  color: var(--amber-800);
  font-weight: 700;
  border-radius: var(--radius-md);
}

.grade-name {
  font-weight: 600;
  color: var(--color-heading);
}

.grade-skills {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  margin: 0;
}

/* ==========================================================================
   Features Section (Home Page)
   ========================================================================== */

.features {
  padding: var(--space-16) 0;
  background: var(--slate-50);
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: var(--space-6);
}

.feature-card {
  padding: var(--space-6);
  background: var(--color-bg-elevated);
  border-radius: var(--radius-lg);
  text-align: center;
  box-shadow: var(--shadow-sm);
}

.feature-icon {
  display: block;
  font-size: 2.5rem;
  margin-bottom: var(--space-3);
}

.feature-card h3 {
  font-size: var(--text-lg);
  color: var(--color-heading);
  margin: 0 0 var(--space-2);
}

.feature-card p {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  margin: 0;
}

.feature-card-link {
  text-decoration: none;
  transition: transform 0.2s, box-shadow 0.2s;
  cursor: pointer;
}

.feature-card-link:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}

.feature-card-link h3 {
  color: var(--color-primary);
}

/* ==========================================================================
   Sections
   ========================================================================== */

.subjects-section,
.units-section,
.lessons-section {
  margin-bottom: var(--space-12);
}

.subjects-section h2,
.units-section h2,
.lessons-section h2 {
  font-family: var(--font-display);
  font-size: var(--text-2xl);
  color: var(--color-heading);
  margin: 0 0 var(--space-6);
}