/* ============================================================================
   Bhodi Learning Platform - Menu v4 Design System
   Converted from React/Tailwind to Vanilla CSS
   ============================================================================ */

/* ============================================================================
   DESIGN TOKENS - Adapted from React globals.css
   ============================================================================ */

:root {
  /* Colors - Light Mode */
  --background: #ffffff;
  --foreground: #1a1a1a;
  --card: #ffffff;
  --card-foreground: #1a1a1a;
  --primary: #030213;
  --primary-foreground: #ffffff;
  --secondary: #f3f3f5;
  --secondary-foreground: #030213;
  --muted: #ececf0;
  --muted-foreground: #717182;
  --accent: #e9ebef;
  --accent-foreground: #030213;
  --border: rgba(0, 0, 0, 0.1);
  --ring: #a8a8a8;

  /* Typography */
  --font-size-xs: 0.75rem;
  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.25rem;
  --font-size-2xl: 1.5rem;
  --font-weight-normal: 400;
  --font-weight-medium: 500;

  /* Spacing */
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;

  /* Border Radius */
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.625rem;
  --radius-xl: 0.75rem;

  /* Shadows */
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);

  /* Layout */
  --container-max-width: 80rem;
  --container-padding: var(--space-4);

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-normal: 200ms ease;
  --transition-slow: 300ms ease;
}

/* Dark Mode - Using existing data-theme attribute pattern */
[data-theme="dark"] {
  --background: #1a1a1a;
  --foreground: #fafafa;
  --card: #1a1a1a;
  --card-foreground: #fafafa;
  --primary: #fafafa;
  --primary-foreground: #2a2a2a;
  --secondary: #2a2a2a;
  --secondary-foreground: #fafafa;
  --muted: #2a2a2a;
  --muted-foreground: #a1a1a1;
  --accent: #2a2a2a;
  --accent-foreground: #fafafa;
  --border: #2a2a2a;
  --ring: #6b6b6b;
}

/* ============================================================================
   BASE STYLES
   ============================================================================ */

.menu-v4 {
  min-height: 100vh;
  background-color: var(--background);
  color: var(--foreground);
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  font-size: var(--font-size-base);
  line-height: 1.5;
}

/* Skip to main content link */
.skip-link {
  position: absolute;
  top: -40px;
  left: 0;
  background: var(--primary);
  color: var(--primary-foreground);
  padding: var(--space-2) var(--space-4);
  border-radius: var(--radius-lg);
  z-index: 100;
  text-decoration: none;
}

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

/* Container */
.container {
  max-width: var(--container-max-width);
  margin: 0 auto;
  padding: 0 var(--container-padding);
}

/* ============================================================================
   HEADER
   ============================================================================ */

.menu-header {
  border-bottom: 1px solid var(--border);
  background-color: var(--background);
}

.menu-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: var(--space-4);
  padding-bottom: var(--space-4);
}

.header-left {
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

.logo-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 2.5rem;
  height: 2.5rem;
  border-radius: var(--radius-lg);
  background-color: var(--primary);
  color: var(--primary-foreground);
  font-size: 1.5rem;
}

.header-text h1 {
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-normal);
  color: var(--foreground);
  margin: 0;
}

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

.header-right {
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

.version-badge {
  display: inline-block;
  padding: var(--space-1) var(--space-3);
  background-color: var(--secondary);
  color: var(--secondary-foreground);
  border-radius: var(--radius-md);
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-medium);
}

.theme-toggle-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--space-2);
  background-color: var(--secondary);
  border: none;
  border-radius: var(--radius-lg);
  cursor: pointer;
  transition: background-color var(--transition-fast);
  color: var(--foreground);
}

.theme-toggle-btn:hover {
  background-color: var(--accent);
}

.theme-toggle-btn svg,
.theme-toggle-btn .icon {
  width: 1.25rem;
  height: 1.25rem;
}

/* ============================================================================
   MAIN CONTENT
   ============================================================================ */

.main-content {
  padding-top: var(--space-12);
  padding-bottom: var(--space-12);
}

/* ============================================================================
   HERO SECTION
   ============================================================================ */

.hero-section {
  text-align: center;
  margin-bottom: var(--space-16);
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-4);
  background-color: var(--secondary);
  color: var(--secondary-foreground);
  border-radius: 9999px;
  margin-bottom: var(--space-6);
  font-size: var(--font-size-sm);
}

.hero-badge .sparkles {
  color: var(--primary);
}

.hero-title {
  font-size: var(--font-size-2xl);
  font-weight: var(--font-weight-medium);
  color: var(--foreground);
  margin: 0 auto var(--space-4);
  max-width: 48rem;
}

.hero-description {
  font-size: var(--font-size-base);
  color: var(--muted-foreground);
  margin: 0 auto var(--space-8);
  max-width: 42rem;
  line-height: 1.6;
}

.primary-cta {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-4) var(--space-8);
  background-color: var(--primary);
  color: var(--primary-foreground);
  border: none;
  border-radius: var(--radius-lg);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-medium);
  cursor: pointer;
  transition: all var(--transition-fast);
  box-shadow: var(--shadow-lg);
  text-decoration: none;
}

.primary-cta:hover {
  opacity: 0.9;
  box-shadow: var(--shadow-xl);
}

.primary-cta:focus-visible {
  outline: 2px solid var(--ring);
  outline-offset: 2px;
}

/* ============================================================================
   LESSONS SECTION
   ============================================================================ */

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

.section-header {
  margin-bottom: var(--space-6);
}

.section-header h3 {
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-medium);
  color: var(--foreground);
  margin: 0 0 var(--space-2) 0;
}

.section-header p {
  font-size: var(--font-size-base);
  color: var(--muted-foreground);
  margin: 0;
}

.lesson-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-6);
}

/* Responsive grid */
@media (min-width: 768px) {
  .lesson-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

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

/* Lesson Card */
.lesson-card {
  position: relative;
  background-color: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius-xl);
  padding: var(--space-6);
  text-align: left;
  cursor: pointer;
  transition: all var(--transition-normal);
  text-decoration: none;
  color: inherit;
  display: block;
}

.lesson-card:hover {
  box-shadow: var(--shadow-lg);
  transform: scale(1.02);
  border-color: rgba(3, 2, 19, 0.2);
}

[data-theme="dark"] .lesson-card:hover {
  border-color: rgba(250, 250, 250, 0.2);
}

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

.lesson-card-header {
  display: flex;
  align-items: start;
  justify-content: space-between;
  gap: var(--space-4);
  margin-bottom: var(--space-4);
}

.lesson-card-left {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  flex: 1;
}

.lesson-number {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 2.5rem;
  height: 2.5rem;
  border-radius: var(--radius-lg);
  background-color: var(--primary);
  color: var(--primary-foreground);
  flex-shrink: 0;
  font-weight: var(--font-weight-medium);
}

.lesson-title-group h3 {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-medium);
  color: var(--foreground);
  margin: 0;
  transition: color var(--transition-fast);
}

.lesson-card:hover .lesson-title-group h3 {
  color: var(--primary);
}

.lesson-title-group p {
  font-size: var(--font-size-sm);
  color: var(--muted-foreground);
  margin: var(--space-1) 0 0 0;
}

.lesson-arrow {
  flex-shrink: 0;
  color: var(--muted-foreground);
  transition: all var(--transition-fast);
}

.lesson-card:hover .lesson-arrow {
  color: var(--primary);
  transform: translateX(0.25rem);
}

.lesson-description {
  font-size: var(--font-size-base);
  color: var(--muted-foreground);
  margin: 0 0 var(--space-4) 0;
  line-height: 1.5;
}

.lesson-concepts {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  margin-bottom: var(--space-4);
}

.concept-tag {
  padding: var(--space-1) var(--space-3);
  background-color: var(--secondary);
  color: var(--secondary-foreground);
  border-radius: 9999px;
  font-size: var(--font-size-sm);
}

.lesson-theme {
  padding-top: var(--space-4);
  border-top: 1px solid var(--border);
  font-size: var(--font-size-sm);
  color: var(--muted-foreground);
}

.lesson-theme span {
  opacity: 0.7;
}

/* ============================================================================
   LEARNING PATHWAY
   ============================================================================ */

.pathway-section {
  background-color: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius-xl);
  padding: var(--space-8);
  margin-bottom: var(--space-12);
}

.pathway-section h3 {
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-medium);
  color: var(--foreground);
  text-align: center;
  margin: 0 0 var(--space-4) 0;
}

.pathway-visualization {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  flex-wrap: wrap;
}

.pathway-step {
  display: flex;
  align-items: center;
}

.pathway-node {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-1);
}

.pathway-circle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 2rem;
  height: 2rem;
  border-radius: 50%;
  background-color: var(--primary);
  color: var(--primary-foreground);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
}

.pathway-label {
  font-size: var(--font-size-xs);
  color: var(--muted-foreground);
  display: none;
}

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

.pathway-connector {
  width: 2rem;
  height: 2px;
  background-color: var(--border);
  margin: 0 var(--space-2);
}

/* ============================================================================
   FEATURES SECTION
   ============================================================================ */

.features-section {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-6);
  margin-bottom: var(--space-12);
}

@media (min-width: 768px) {
  .features-section {
    grid-template-columns: repeat(3, 1fr);
  }
}

.feature-card {
  text-align: center;
  padding: var(--space-6);
}

.feature-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 3rem;
  height: 3rem;
  border-radius: var(--radius-lg);
  background-color: var(--secondary);
  margin-bottom: var(--space-4);
  font-size: 1.5rem;
}

.feature-icon.primary {
  color: var(--primary);
}

.feature-card h4 {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-medium);
  color: var(--foreground);
  margin: 0 0 var(--space-2) 0;
}

.feature-card p {
  font-size: var(--font-size-base);
  color: var(--muted-foreground);
  margin: 0;
  line-height: 1.6;
}

/* ============================================================================
   FOOTER
   ============================================================================ */

.menu-footer {
  border-top: 1px solid var(--border);
  margin-top: auto;
}

.menu-footer .container {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
  padding-top: var(--space-8);
  padding-bottom: var(--space-8);
}

@media (min-width: 768px) {
  .menu-footer .container {
    flex-direction: row;
  }
}

.footer-text {
  text-align: center;
}

@media (min-width: 768px) {
  .footer-text {
    text-align: left;
  }
}

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

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

.footer-brand .icon {
  width: 1.25rem;
  height: 1.25rem;
  color: var(--muted-foreground);
}

.footer-brand span {
  font-size: var(--font-size-sm);
  color: var(--muted-foreground);
}

/* ============================================================================
   RESPONSIVE TYPOGRAPHY
   ============================================================================ */

@media (min-width: 768px) {
  .hero-title {
    font-size: 2rem;
  }
}

@media (min-width: 1024px) {
  .hero-title {
    font-size: 2.25rem;
  }
}

/* ============================================================================
   ACCESSIBILITY
   ============================================================================ */

button:focus-visible,
a:focus-visible {
  outline: 2px solid var(--ring);
  outline-offset: 2px;
}

/* Reduced motion support */
@media (prefers-reduced-motion: reduce) {
  * {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}