/**
 * LSIB.io (Law School in a Box)
 * Core Design System & Stylesheet
 * Stanford Law School Branding
 *
 * Color Palette:
 * - Primary: #8C1515 (Stanford Cardinal)
 * - Primary Dark: #5C0A0A
 * - Primary Light: #D4AF37 (Stanford Gold)
 * - Accent: #175E54 (Palo Alto Green)
 * - Accent Dark: #0D3C35
 * - Secondary: #737373 (Cool Grey)
 */

/* ================================================================
   CSS CUSTOM PROPERTIES / ROOT VARIABLES
   ================================================================ */

:root {
  /* Colors */
  --color-primary: #8C1515;
  --color-primary-dark: #5C0A0A;
  --color-primary-light: #D4AF37;
  --color-accent: #175E54;
  --color-accent-dark: #0D3C35;
  --color-secondary: #737373;
  --color-neutral-50: #F9F9F9;
  --color-neutral-100: #F2F2F2;
  --color-neutral-200: #E0E0E0;
  --color-neutral-300: #CCCCCC;
  --color-neutral-400: #999999;
  --color-neutral-500: #666666;
  --color-neutral-600: #333333;
  --color-neutral-700: #1A1A1A;
  --color-white: #FFFFFF;
  --color-black: #000000;

  /* Dark Slate Colors (MSIB Design System) */
  --color-dark-slate: #2E4057;
  --color-dark-slate-deep: #1A2A3A;
  --color-body-bg: #FAFAFA;

  /* Semantic Colors */
  --color-success: #22C55E;
  --color-warning: #F59E0B;
  --color-error: #EF4444;
  --color-info: #3B82F6;

  /* Typography */
  --font-serif: 'Source Serif 4', Georgia, serif;
  --font-sans: 'Source Sans 3', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: 'Source Code Pro', 'Courier New', monospace;

  /* Font Sizes */
  --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-size-3xl: 1.875rem;
  --font-size-4xl: 2.25rem;
  --font-size-5xl: 3rem;

  /* Line Heights */
  --line-height-tight: 1.2;
  --line-height-normal: 1.5;
  --line-height-relaxed: 1.75;

  /* Letter Spacing */
  --letter-spacing-tight: -0.02em;
  --letter-spacing-normal: 0;
  --letter-spacing-wide: 0.04em;

  /* Spacing Scale */
  --space-0: 0;
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-20: 5rem;
  --space-24: 6rem;
  --space-32: 8rem;

  /* Border Radius */
  --radius-none: 0;
  --radius-sm: 0.25rem;
  --radius-base: 0.5rem;
  --radius-md: 0.75rem;
  --radius-lg: 1rem;
  --radius-xl: 1.5rem;
  --radius-2xl: 2rem;
  --radius-full: 9999px;

  /* Shadows */
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-base: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px 0 rgba(0, 0, 0, 0.06);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --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);

  /* Transitions */
  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 350ms cubic-bezier(0.4, 0, 0.2, 1);

  /* Layout */
  --container-max-width: 1280px;
  --container-padding: 1.5rem;

  /* Z-index Scale */
  --z-dropdown: 1000;
  --z-sticky: 1020;
  --z-fixed: 1030;
  --z-modal-backdrop: 1040;
  --z-modal: 1050;
}

/* ================================================================
   RESPONSIVE BREAKPOINTS
   ================================================================ */

/* Mobile: < 640px (default) */
/* Tablet: 768px and up (@media (min-width: 768px)) */
/* Desktop: 1024px and up (@media (min-width: 1024px)) */
/* Large Desktop: 1280px and up (@media (min-width: 1280px)) */

/* ================================================================
   RESET & BASE STYLES
   ================================================================ */

*,
*::before,
*::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: var(--font-sans);
  font-size: var(--font-size-base);
  line-height: var(--line-height-normal);
  color: var(--color-neutral-700);
  background-color: var(--color-body-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

h1,
h2,
h3,
h4,
h5,
h6 {
  font-family: var(--font-serif);
  font-weight: 700;
  line-height: var(--line-height-tight);
  color: var(--color-primary-dark);
}

h1 {
  font-size: var(--font-size-4xl);
  margin-bottom: var(--space-6);
}

h2 {
  font-size: var(--font-size-3xl);
  margin-bottom: var(--space-4);
}

h3 {
  font-size: var(--font-size-2xl);
  margin-bottom: var(--space-3);
}

h4 {
  font-size: var(--font-size-xl);
  margin-bottom: var(--space-2);
}

h5 {
  font-size: var(--font-size-lg);
  margin-bottom: var(--space-2);
}

h6 {
  font-size: var(--font-size-base);
  margin-bottom: var(--space-2);
}

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

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--color-primary-dark);
  text-decoration: underline;
}

button {
  font-family: var(--font-sans);
  cursor: pointer;
  border: none;
  background: none;
}

code {
  font-family: var(--font-mono);
  font-size: 0.95em;
  background-color: var(--color-neutral-100);
  padding: var(--space-1) var(--space-2);
  border-radius: var(--radius-sm);
}

pre {
  background-color: var(--color-neutral-700);
  color: var(--color-neutral-50);
  padding: var(--space-4);
  border-radius: var(--radius-base);
  overflow-x: auto;
  margin-bottom: var(--space-4);
}

pre code {
  background-color: transparent;
  padding: 0;
  color: inherit;
}

/* ================================================================
   CONTAINER & LAYOUT
   ================================================================ */

.container {
  width: 100%;
  max-width: var(--container-max-width);
  margin: 0 auto;
  padding: 0 var(--container-padding);
}

.grid {
  display: grid;
  gap: var(--space-6);
}

.grid-cols-1 {
  grid-template-columns: 1fr;
}

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

  .grid-cols-3 {
    grid-template-columns: repeat(3, 1fr);
  }
}

@media (min-width: 1024px) {
  .grid-cols-4 {
    grid-template-columns: repeat(4, 1fr);
  }
}

.flex {
  display: flex;
}

.flex-col {
  flex-direction: column;
}

.flex-wrap {
  flex-wrap: wrap;
}

.justify-between {
  justify-content: space-between;
}

.justify-center {
  justify-content: center;
}

.items-center {
  align-items: center;
}

.items-start {
  align-items: flex-start;
}

.gap-4 {
  gap: var(--space-4);
}

.gap-6 {
  gap: var(--space-6);
}

.gap-8 {
  gap: var(--space-8);
}

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

.text-xs {
  font-size: var(--font-size-xs);
}

.text-sm {
  font-size: var(--font-size-sm);
}

.text-base {
  font-size: var(--font-size-base);
}

.text-lg {
  font-size: var(--font-size-lg);
}

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

.text-2xl {
  font-size: var(--font-size-2xl);
}

.text-3xl {
  font-size: var(--font-size-3xl);
}

.font-light {
  font-weight: 300;
}

.font-normal {
  font-weight: 400;
}

.font-semibold {
  font-weight: 600;
}

.font-bold {
  font-weight: 700;
}

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

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

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

.text-muted {
  color: var(--color-secondary);
}

.text-error {
  color: var(--color-error);
}

.text-success {
  color: var(--color-success);
}

.text-warning {
  color: var(--color-warning);
}

/* ================================================================
   NAVIGATION BAR
   ================================================================ */

.navbar {
  background-color: var(--color-dark-slate);
  border-bottom: 1px solid rgba(0, 0, 0, 0.2);
  position: sticky;
  top: 0;
  z-index: var(--z-sticky);
  box-shadow: var(--shadow-sm);
}

.navbar-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: var(--space-3) var(--space-6);
}

.navbar-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--space-4) 0;
}

.navbar-brand {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  font-family: var(--font-serif);
  font-size: var(--font-size-xl);
  font-weight: 700;
  color: var(--color-white);
  text-decoration: none;
}

.navbar-logo {
  width: 40px;
  height: 40px;
  background-color: var(--color-primary);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--font-size-lg);
  color: var(--color-white);
  font-weight: 700;
}

.navbar-brand:hover {
  color: var(--color-primary-light);
}

.navbar-menu {
  display: none;
  list-style: none;
  gap: var(--space-8);
}

@media (min-width: 768px) {
  .navbar-menu {
    display: flex;
  }
}

.navbar-menu-item {
  font-size: var(--font-size-sm);
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: var(--letter-spacing-wide);
}

.navbar-menu-item a {
  color: var(--color-white);
  transition: color var(--transition-fast);
  display: block;
  padding: var(--space-2) 0;
  border-bottom: 2px solid transparent;
}

.navbar-menu-item a:hover,
.navbar-menu-item a.active {
  color: var(--color-primary-light);
  border-bottom-color: var(--color-primary-light);
}

.navbar-actions {
  display: flex;
  align-items: center;
  gap: var(--space-4);
}

.navbar-toggle {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
  padding: var(--space-2);
  border: none;
  background: none;
  cursor: pointer;
}

@media (min-width: 768px) {
  .navbar-toggle {
    display: none;
  }
}

.navbar-toggle span {
  width: 24px;
  height: 2px;
  background-color: var(--color-white);
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
}

.navbar-toggle.active span:nth-child(1) {
  transform: rotate(45deg) translate(8px, 8px);
}

.navbar-toggle.active span:nth-child(2) {
  opacity: 0;
}

.navbar-toggle.active span:nth-child(3) {
  transform: rotate(-45deg) translate(7px, -7px);
}

/* Mobile Menu */
.mobile-menu {
  display: none;
  flex-direction: column;
  gap: var(--space-4);
  padding: var(--space-6) 0;
  border-top: 1px solid rgba(255, 255, 255, 0.2);
  background-color: var(--color-dark-slate-deep);
}

.mobile-menu.active {
  display: flex;
}

.mobile-menu-item {
  padding: var(--space-3) 0;
  font-size: var(--font-size-sm);
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: var(--letter-spacing-wide);
}

.mobile-menu-item a {
  color: var(--color-white);
}

.mobile-menu-item a:hover,
.mobile-menu-item a.active {
  color: var(--color-primary-light);
}

/* ================================================================
   BUTTONS
   ================================================================ */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-4);
  font-size: var(--font-size-sm);
  font-weight: 600;
  border-radius: var(--radius-base);
  cursor: pointer;
  transition: all var(--transition-fast);
  text-decoration: none;
  border: 2px solid transparent;
}

.btn:hover {
  text-decoration: none;
}

/* Primary Button */
.btn-primary {
  background-color: var(--color-primary);
  color: var(--color-white);
}

.btn-primary:hover {
  background-color: var(--color-primary-dark);
}

/* Secondary Button */
.btn-secondary {
  background-color: var(--color-neutral-100);
  color: var(--color-neutral-700);
  border-color: var(--color-neutral-200);
  border-width: 1px;
}

.btn-secondary:hover {
  background-color: var(--color-neutral-200);
}

/* Accent Button */
.btn-accent {
  background-color: var(--color-accent);
  color: var(--color-white);
}

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

/* Outline Button */
.btn-outline {
  border: 2px solid var(--color-primary);
  color: var(--color-primary);
  background-color: transparent;
}

.btn-outline:hover {
  background-color: var(--color-neutral-50);
}

/* Small Button */
.btn-sm {
  padding: var(--space-1) var(--space-3);
  font-size: var(--font-size-xs);
}

/* Large Button */
.btn-lg {
  padding: var(--space-3) var(--space-6);
  font-size: var(--font-size-base);
}

/* Full Width Button */
.btn-block {
  width: 100%;
}

/* ================================================================
   BADGES & TAGS
   ================================================================ */

.badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  padding: var(--space-1) var(--space-2);
  font-size: var(--font-size-xs);
  font-weight: 600;
  border-radius: var(--radius-full);
  text-transform: uppercase;
  letter-spacing: var(--letter-spacing-wide);
  width: fit-content;
}

.badge-primary {
  background-color: var(--color-primary-light);
  color: var(--color-primary-dark);
}

.badge-accent {
  background-color: var(--color-accent);
  color: var(--color-white);
}

.badge-secondary {
  background-color: var(--color-neutral-200);
  color: var(--color-neutral-600);
}

.badge-success {
  background-color: #D1FAE5;
  color: #065F46;
}

.badge-warning {
  background-color: #FEF3C7;
  color: #92400E;
}

.badge-error {
  background-color: #FEE2E2;
  color: #991B1B;
}

.phase-tag {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-md);
  font-weight: 700;
  font-size: var(--font-size-sm);
  color: var(--color-white);
  text-align: center;
}

.phase-1l {
  background-color: #E11D48;
}

.phase-2l {
  background-color: #7C3AED;
}

.phase-3l {
  background-color: #0891B2;
}

/* ================================================================
   COURSE CARDS
   ================================================================ */

.course-card {
  background-color: var(--color-white);
  border: 1.25px solid #E0DCD8;
  border-radius: 8px;
  padding: 24px;
  transition: all var(--transition-base);
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
  cursor: pointer;
}

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

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

.course-card-title {
  font-size: var(--font-size-lg);
  font-family: var(--font-serif);
  font-weight: 700;
  color: var(--color-primary-dark);
}

.course-card-code {
  font-family: var(--font-mono);
  font-size: var(--font-size-sm);
  color: var(--color-secondary);
  font-weight: 600;
}

.course-card-description {
  font-size: var(--font-size-sm);
  color: var(--color-neutral-600);
  line-height: var(--line-height-relaxed);
}

.course-card-meta {
  display: flex;
  gap: var(--space-4);
  flex-wrap: wrap;
  padding-top: var(--space-4);
  border-top: 1px solid var(--color-neutral-200);
  font-size: var(--font-size-xs);
  color: var(--color-neutral-500);
}

.course-card-meta-item {
  display: flex;
  gap: var(--space-1);
  align-items: center;
}

.course-card-meta-icon {
  width: 16px;
  height: 16px;
}

.course-card-actions {
  display: flex;
  gap: var(--space-2);
  margin-top: auto;
}

/* ================================================================
   COURSE GRID
   ================================================================ */

.course-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: var(--space-6);
  margin-bottom: var(--space-12);
}

.phase-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: var(--space-6);
  margin-bottom: var(--space-12);
}

/* ================================================================
   HERO SECTION (MSIB-style dark gradient)
   ================================================================ */

.hero {
  background: linear-gradient(135deg, #2E4057 0%, #1A2A3A 100%);
  text-align: center;
  padding: var(--space-16) var(--space-6);
  color: var(--color-white);
}

.hero-content {
  max-width: 800px;
  margin: 0 auto;
}

.hero__badge {
  display: inline-block;
  background-color: var(--color-primary);
  color: var(--color-white);
  padding: 4px 16px;
  border-radius: 20px;
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: var(--space-4);
  letter-spacing: 0.02em;
}

.hero-title {
  font-size: 2.75rem;
  font-weight: 700;
  color: var(--color-white);
  margin-bottom: var(--space-4);
  font-family: var(--font-serif);
}

.hero-subtitle {
  font-size: var(--font-size-lg);
  color: rgba(255, 255, 255, 0.85);
  max-width: 700px;
  margin: 0 auto var(--space-8);
  line-height: var(--line-height-relaxed);
}

.hero__stats {
  display: flex;
  justify-content: center;
  gap: var(--space-12);
  margin-top: var(--space-6);
}

.hero__stat {
  text-align: center;
}

.hero__stat-number {
  display: block;
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--color-white);
  line-height: 1;
}

.hero__stat-label {
  display: block;
  font-size: var(--font-size-sm);
  color: rgba(255, 255, 255, 0.7);
  margin-top: var(--space-1);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

/* ================================================================
   SEARCH SECTION (between hero and curriculum)
   ================================================================ */

.search-section {
  padding: var(--space-4) var(--space-6);
  border-bottom: 1px solid var(--color-neutral-200);
  background-color: var(--color-white);
}

.search-input {
  width: 100%;
  max-width: 500px;
  padding: var(--space-3) var(--space-4);
  border: 1px solid var(--color-neutral-300);
  border-radius: var(--radius-base);
  font-size: var(--font-size-base);
  font-family: var(--font-sans);
  transition: border-color var(--transition-fast);
}

.search-input:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(140, 21, 21, 0.1);
}

/* ================================================================
   COURSE CARD MSIB-STYLE ELEMENTS
   ================================================================ */

.course-card__phase-tag {
  display: inline-block;
  color: var(--color-white);
  padding: 2px 10px;
  border-radius: 4px;
  font-size: 0.7rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: var(--space-2);
  width: fit-content;
}

.course-card__code {
  font-family: var(--font-mono);
  font-size: var(--font-size-sm);
  color: var(--color-secondary);
  font-weight: 600;
  margin-bottom: var(--space-2);
}

.course-card__description {
  font-size: var(--font-size-sm);
  color: var(--color-neutral-500);
  line-height: var(--line-height-relaxed);
  flex-grow: 1;
}

.course-card__meta {
  display: flex;
  gap: var(--space-4);
  margin-top: auto;
  padding-top: var(--space-3);
}

.course-card__meta-item {
  font-size: var(--font-size-sm);
  color: var(--color-secondary);
  font-weight: 500;
}

/* Ensure a.course-card looks right */
a.course-card {
  text-decoration: none;
  color: inherit;
  display: flex;
  flex-direction: column;
}

a.course-card:hover {
  text-decoration: none;
}

a.course-card .course-title {
  color: var(--color-primary-dark);
}

/* ================================================================
   NAVBAR LINK OVERRIDES (dark nav)
   ================================================================ */

.navbar .nav-link {
  color: rgba(255, 255, 255, 0.85);
  font-size: var(--font-size-sm);
  font-weight: 500;
  transition: color var(--transition-fast);
}

.navbar .nav-link:hover {
  color: var(--color-white);
  text-decoration: none;
}

.navbar .btn-signin {
  color: rgba(255, 255, 255, 0.85);
  font-size: var(--font-size-sm);
}

.navbar .btn-signin:hover {
  color: var(--color-white);
}

.navbar .btn-signup {
  background-color: var(--color-primary);
  color: var(--color-white);
  padding: 4px 12px;
  border-radius: var(--radius-base);
  font-size: var(--font-size-sm);
  font-weight: 600;
}

.navbar .btn-signup:hover {
  background-color: var(--color-primary-dark);
  text-decoration: none;
}

.navbar .logo {
  color: var(--color-white);
  font-family: var(--font-serif);
  font-size: var(--font-size-xl);
  font-weight: 700;
}

.navbar .logo:hover {
  color: var(--color-primary-light);
  text-decoration: none;
}

/* ================================================================
   SITE FOOTER (MSIB-style dark)
   ================================================================ */

.site-footer {
  background-color: #2E4057;
  color: var(--color-white);
  padding: var(--space-12) var(--space-6) var(--space-6);
}

.site-footer .footer-content {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-8);
  max-width: var(--container-max-width);
  margin: 0 auto;
  padding-bottom: var(--space-8);
  border-bottom: 1px solid rgba(255, 255, 255, 0.2);
}

@media (max-width: 768px) {
  .site-footer .footer-content {
    grid-template-columns: repeat(2, 1fr);
  }
}

.site-footer .footer-col h4 {
  color: var(--color-white);
  font-size: var(--font-size-base);
  margin-bottom: var(--space-4);
}

.site-footer .footer-col ul {
  list-style: none;
  padding: 0;
  margin: 0;
}

.site-footer .footer-col ul li {
  margin-bottom: var(--space-2);
}

.site-footer .footer-col ul li a {
  color: rgba(255, 255, 255, 0.7);
  font-size: var(--font-size-sm);
  transition: color var(--transition-fast);
}

.site-footer .footer-col ul li a:hover {
  color: var(--color-white);
  text-decoration: none;
}

.site-footer .footer-bottom {
  max-width: var(--container-max-width);
  margin: 0 auto;
  padding-top: var(--space-6);
  text-align: center;
}

.site-footer .footer-bottom p {
  color: rgba(255, 255, 255, 0.5);
  font-size: var(--font-size-sm);
}

/* ================================================================
   SEARCH & FILTER
   ================================================================ */

.search-box {
  position: relative;
  width: 100%;
  max-width: 500px;
}

.search-box input {
  width: 100%;
  padding: var(--space-3) var(--space-4);
  padding-left: var(--space-10);
  border: 1px solid var(--color-neutral-300);
  border-radius: var(--radius-base);
  font-size: var(--font-size-base);
  font-family: var(--font-sans);
  transition: border-color var(--transition-fast);
}

.search-box input:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(140, 21, 21, 0.1);
}

.search-box::before {
  content: '🔍';
  position: absolute;
  left: var(--space-3);
  top: 50%;
  transform: translateY(-50%);
  font-size: var(--font-size-lg);
}

.filter-group {
  display: flex;
  gap: var(--space-2);
  flex-wrap: wrap;
}

.filter-button {
  padding: var(--space-2) var(--space-3);
  background-color: var(--color-neutral-100);
  border: 1px solid var(--color-neutral-300);
  border-radius: var(--radius-full);
  cursor: pointer;
  font-size: var(--font-size-sm);
  transition: all var(--transition-fast);
}

.filter-button:hover,
.filter-button.active {
  background-color: var(--color-primary);
  color: var(--color-white);
  border-color: var(--color-primary);
}

/* ================================================================
   SIDEBAR
   ================================================================ */

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

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

.sidebar {
  position: sticky;
  top: 100px;
  height: fit-content;
}

.sidebar-section {
  margin-bottom: var(--space-8);
}

.sidebar-title {
  font-family: var(--font-serif);
  font-size: var(--font-size-lg);
  font-weight: 700;
  color: var(--color-primary-dark);
  margin-bottom: var(--space-4);
  padding-bottom: var(--space-2);
  border-bottom: 2px solid var(--color-neutral-200);
}

.sidebar-menu {
  list-style: none;
}

.sidebar-menu-item {
  margin-bottom: var(--space-2);
}

.sidebar-menu-item a {
  display: block;
  padding: var(--space-2) var(--space-3);
  border-left: 3px solid transparent;
  color: var(--color-neutral-600);
  font-size: var(--font-size-sm);
  transition: all var(--transition-fast);
}

.sidebar-menu-item a:hover,
.sidebar-menu-item a.active {
  color: var(--color-primary);
  border-left-color: var(--color-primary);
  padding-left: var(--space-4);
}

/* ================================================================
   FORMS
   ================================================================ */

.form-group {
  margin-bottom: var(--space-6);
  display: flex;
  flex-direction: column;
}

.form-label {
  font-weight: 600;
  font-size: var(--font-size-sm);
  margin-bottom: var(--space-2);
  color: var(--color-neutral-700);
}

.form-label.required::after {
  content: ' *';
  color: var(--color-error);
}

.form-input,
.form-textarea,
.form-select {
  padding: var(--space-3) var(--space-4);
  border: 1px solid var(--color-neutral-300);
  border-radius: var(--radius-base);
  font-size: var(--font-size-base);
  font-family: var(--font-sans);
  transition: border-color var(--transition-fast);
  width: 100%;
}

.form-input:focus,
.form-textarea:focus,
.form-select:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(140, 21, 21, 0.1);
}

.form-textarea {
  resize: vertical;
  min-height: 120px;
  font-family: var(--font-sans);
}

.form-helper {
  font-size: var(--font-size-xs);
  color: var(--color-secondary);
  margin-top: var(--space-1);
}

.form-error {
  color: var(--color-error);
  font-size: var(--font-size-sm);
  margin-top: var(--space-1);
}

.form-success {
  color: var(--color-success);
  font-size: var(--font-size-sm);
  margin-top: var(--space-1);
}

.checkbox,
.radio {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  cursor: pointer;
  font-size: var(--font-size-base);
}

.checkbox input,
.radio input {
  cursor: pointer;
}

/* ================================================================
   MODALS / DIALOGS
   ================================================================ */

.modal-backdrop {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: rgba(0, 0, 0, 0.5);
  z-index: var(--z-modal-backdrop);
}

.modal-backdrop.active {
  display: flex;
  align-items: center;
  justify-content: center;
}

.modal {
  position: relative;
  background-color: var(--color-white);
  border-radius: var(--radius-lg);
  padding: var(--space-8);
  max-width: 500px;
  width: 90%;
  max-height: 90vh;
  overflow-y: auto;
  z-index: var(--z-modal);
  animation: slideUp 0.3s ease-out;
}

@keyframes slideUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.modal-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--space-6);
  padding-bottom: var(--space-4);
  border-bottom: 1px solid var(--color-neutral-200);
}

.modal-title {
  font-size: var(--font-size-2xl);
  font-family: var(--font-serif);
  font-weight: 700;
  color: var(--color-primary-dark);
}

.modal-close {
  background: none;
  border: none;
  font-size: var(--font-size-2xl);
  cursor: pointer;
  color: var(--color-neutral-400);
  transition: color var(--transition-fast);
}

.modal-close:hover {
  color: var(--color-neutral-600);
}

.modal-body {
  margin-bottom: var(--space-6);
}

.modal-footer {
  display: flex;
  gap: var(--space-4);
  justify-content: flex-end;
}

/* ================================================================
   QUIZ STYLES
   ================================================================ */

.quiz-container {
  max-width: 800px;
  margin: 0 auto;
}

.quiz-header {
  background-color: var(--color-primary);
  color: var(--color-white);
  padding: var(--space-8);
  border-radius: var(--radius-lg);
  margin-bottom: var(--space-8);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.quiz-title {
  font-size: var(--font-size-2xl);
  font-family: var(--font-serif);
  margin-bottom: var(--space-2);
}

.quiz-timer {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--font-size-lg);
  font-weight: 700;
}

.quiz-timer.warning {
  color: var(--color-warning);
}

.quiz-timer.danger {
  color: var(--color-error);
}

.quiz-progress {
  background-color: var(--color-neutral-200);
  height: 8px;
  border-radius: var(--radius-full);
  overflow: hidden;
  margin-bottom: var(--space-6);
}

.quiz-progress-bar {
  background-color: var(--color-primary);
  height: 100%;
  transition: width 0.3s ease;
}

.quiz-question {
  background-color: var(--color-white);
  border: 1px solid var(--color-neutral-200);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  margin-bottom: var(--space-6);
}

.quiz-question-number {
  font-size: var(--font-size-sm);
  color: var(--color-secondary);
  font-weight: 600;
  margin-bottom: var(--space-2);
}

.quiz-question-text {
  font-size: var(--font-size-lg);
  font-family: var(--font-serif);
  font-weight: 700;
  color: var(--color-primary-dark);
  margin-bottom: var(--space-6);
  line-height: var(--line-height-relaxed);
}

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

.quiz-option {
  display: flex;
  align-items: flex-start;
  gap: var(--space-3);
  padding: var(--space-4);
  border: 2px solid var(--color-neutral-300);
  border-radius: var(--radius-base);
  cursor: pointer;
  transition: all var(--transition-fast);
  background-color: var(--color-neutral-50);
}

.quiz-option:hover {
  background-color: var(--color-white);
  border-color: var(--color-primary);
}

.quiz-option input {
  width: 24px;
  height: 24px;
  margin-top: var(--space-1);
  cursor: pointer;
}

.quiz-option-label {
  cursor: pointer;
  flex: 1;
  font-size: var(--font-size-base);
  line-height: var(--line-height-relaxed);
}

.quiz-option.selected {
  background-color: #EBF5FF;
  border-color: var(--color-primary);
}

.quiz-option.correct {
  background-color: #D1FAE5;
  border-color: var(--color-success);
}

.quiz-option.incorrect {
  background-color: #FEE2E2;
  border-color: var(--color-error);
}

.quiz-explanation {
  background-color: var(--color-neutral-50);
  border-left: 4px solid var(--color-primary);
  padding: var(--space-4);
  border-radius: var(--radius-base);
  margin-top: var(--space-4);
  font-size: var(--font-size-sm);
  line-height: var(--line-height-relaxed);
}

.quiz-controls {
  display: flex;
  gap: var(--space-4);
  justify-content: space-between;
  margin-top: var(--space-8);
}

.quiz-score-card {
  background-color: var(--color-primary);
  color: var(--color-white);
  padding: var(--space-12);
  border-radius: var(--radius-lg);
  text-align: center;
  margin-bottom: var(--space-8);
}

.quiz-score-value {
  font-size: var(--font-size-5xl);
  font-family: var(--font-serif);
  font-weight: 700;
  margin-bottom: var(--space-2);
}

.quiz-score-label {
  font-size: var(--font-size-lg);
  margin-bottom: var(--space-4);
}

.quiz-score-breakdown {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-4);
  margin-top: var(--space-6);
  padding-top: var(--space-6);
  border-top: 1px solid rgba(255, 255, 255, 0.2);
}

.quiz-score-item {
  text-align: center;
}

.quiz-score-number {
  font-size: var(--font-size-3xl);
  font-weight: 700;
  margin-bottom: var(--space-1);
}

.quiz-score-label-small {
  font-size: var(--font-size-sm);
}

/* ================================================================
   LOUNGE / CHAT STYLES
   ================================================================ */

.lounge-container {
  display: grid;
  grid-template-columns: 1fr;
  height: 600px;
}

@media (min-width: 1024px) {
  .lounge-container {
    grid-template-columns: 200px 1fr;
    gap: var(--space-6);
  }
}

.lounge-users {
  border: 1px solid var(--color-neutral-200);
  border-radius: var(--radius-lg);
  padding: var(--space-4);
  background-color: var(--color-neutral-50);
}

.lounge-users-title {
  font-weight: 700;
  font-size: var(--font-size-sm);
  margin-bottom: var(--space-3);
  text-transform: uppercase;
  letter-spacing: var(--letter-spacing-wide);
}

.lounge-users-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.lounge-user-item {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2);
  font-size: var(--font-size-sm);
}

.lounge-user-avatar {
  width: 32px;
  height: 32px;
  border-radius: var(--radius-full);
  background-color: var(--color-primary);
  color: var(--color-white);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: var(--font-size-xs);
}

.lounge-messages {
  display: flex;
  flex-direction: column;
  border: 1px solid var(--color-neutral-200);
  border-radius: var(--radius-lg);
  overflow: hidden;
}

.lounge-messages-list {
  flex: 1;
  overflow-y: auto;
  padding: var(--space-4);
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.lounge-message {
  display: flex;
  gap: var(--space-2);
}

.lounge-message.own {
  justify-content: flex-end;
}

.lounge-message-avatar {
  width: 32px;
  height: 32px;
  border-radius: var(--radius-full);
  background-color: var(--color-accent);
  color: var(--color-white);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: var(--font-size-xs);
  flex-shrink: 0;
}

.lounge-message-bubble {
  max-width: 70%;
  padding: var(--space-3) var(--space-4);
  border-radius: var(--radius-base);
  background-color: var(--color-neutral-100);
  font-size: var(--font-size-sm);
  line-height: var(--line-height-relaxed);
}

.lounge-message.own .lounge-message-bubble {
  background-color: var(--color-primary);
  color: var(--color-white);
}

.lounge-input-group {
  display: flex;
  gap: var(--space-2);
  padding: var(--space-4);
  border-top: 1px solid var(--color-neutral-200);
}

.lounge-input {
  flex: 1;
  padding: var(--space-3) var(--space-4);
  border: 1px solid var(--color-neutral-300);
  border-radius: var(--radius-base);
  font-size: var(--font-size-sm);
  font-family: var(--font-sans);
}

.lounge-input:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(140, 21, 21, 0.1);
}

.lounge-send {
  padding: var(--space-3) var(--space-4);
  background-color: var(--color-primary);
  color: var(--color-white);
  border-radius: var(--radius-base);
  cursor: pointer;
  font-weight: 600;
  transition: background-color var(--transition-fast);
}

.lounge-send:hover {
  background-color: var(--color-primary-dark);
}

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

footer {
  background-color: var(--color-dark-slate);
  color: var(--color-white);
  margin-top: var(--space-20);
  padding: var(--space-12) 0;
}

.footer-content {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-12);
  margin-bottom: var(--space-12);
}

@media (max-width: 1023px) {
  .footer-content {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .footer-content {
    grid-template-columns: 1fr;
  }
}

.footer-section-title {
  font-family: var(--font-serif);
  font-size: var(--font-size-lg);
  font-weight: 700;
  margin-bottom: var(--space-4);
}

.footer-menu {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.footer-menu-item a {
  color: rgba(255, 255, 255, 0.75);
  font-size: var(--font-size-sm);
  transition: color var(--transition-fast);
}

.footer-menu-item a:hover {
  color: var(--color-primary-light);
  text-decoration: underline;
}

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.2);
  padding-top: var(--space-8);
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--space-4);
}

.footer-copyright {
  font-size: var(--font-size-sm);
  color: rgba(255, 255, 255, 0.6);
}

.footer-social {
  display: flex;
  gap: var(--space-4);
}

.footer-social a {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  background-color: rgba(255, 255, 255, 0.15);
  border-radius: var(--radius-full);
  transition: all var(--transition-fast);
}

.footer-social a:hover {
  background-color: var(--color-primary);
}

/* ================================================================
   ALERTS
   ================================================================ */

.alert {
  padding: var(--space-4);
  border-radius: var(--radius-base);
  margin-bottom: var(--space-4);
  display: flex;
  gap: var(--space-3);
  align-items: flex-start;
}

.alert-icon {
  flex-shrink: 0;
  font-size: var(--font-size-lg);
}

.alert-content {
  flex: 1;
}

.alert-title {
  font-weight: 600;
  margin-bottom: var(--space-1);
}

.alert-message {
  font-size: var(--font-size-sm);
  line-height: var(--line-height-relaxed);
}

.alert-success {
  background-color: #D1FAE5;
  color: #065F46;
  border-left: 4px solid var(--color-success);
}

.alert-warning {
  background-color: #FEF3C7;
  color: #92400E;
  border-left: 4px solid var(--color-warning);
}

.alert-error {
  background-color: #FEE2E2;
  color: #991B1B;
  border-left: 4px solid var(--color-error);
}

.alert-info {
  background-color: #DBEAFE;
  color: #0C2340;
  border-left: 4px solid var(--color-info);
}

/* ================================================================
   UTILITY CLASSES
   ================================================================ */

.hidden {
  display: none;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border-width: 0;
}

.max-w-screen-xl {
  max-width: var(--container-max-width);
}

.mx-auto {
  margin-left: auto;
  margin-right: auto;
}

.mt-8 {
  margin-top: var(--space-8);
}

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

.my-8 {
  margin-top: var(--space-8);
  margin-bottom: var(--space-8);
}

.pt-12 {
  padding-top: var(--space-12);
}

.pb-12 {
  padding-bottom: var(--space-12);
}

.px-4 {
  padding-left: var(--space-4);
  padding-right: var(--space-4);
}

.py-6 {
  padding-top: var(--space-6);
  padding-bottom: var(--space-6);
}

/* ================================================================
   ANIMATIONS
   ================================================================ */

@keyframes fadeIn {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}

@keyframes slideInDown {
  from {
    opacity: 0;
    transform: translateY(-10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes slideInUp {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes spin {
  from {
    transform: rotate(0deg);
  }
  to {
    transform: rotate(360deg);
  }
}

.animate-fade-in {
  animation: fadeIn 0.3s ease-in;
}

.animate-slide-in-down {
  animation: slideInDown 0.3s ease-out;
}

.animate-slide-in-up {
  animation: slideInUp 0.3s ease-out;
}

.animate-spin {
  animation: spin 1s linear infinite;
}

/* ================================================================
   PRINT STYLES
   ================================================================ */

@media print {
  .navbar,
  footer,
  .sidebar,
  .quiz-controls {
    display: none;
  }

  body {
    background-color: var(--color-white);
  }

  .course-card {
    page-break-inside: avoid;
  }

  .quiz-question {
    page-break-inside: avoid;
  }
}

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

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

@media (prefers-color-scheme: dark) {
  /* Optional: Add dark mode support here */
}

/* ================================================================
   LOADING STATES
   ================================================================ */

.skeleton {
  background: linear-gradient(
    90deg,
    var(--color-neutral-200) 25%,
    var(--color-neutral-100) 50%,
    var(--color-neutral-200) 75%
  );
  background-size: 200% 100%;
  animation: loading 1.5s infinite;
}

@keyframes loading {
  0% {
    background-position: 200% 0;
  }
  100% {
    background-position: -200% 0;
  }
}

.skeleton-text {
  height: 1rem;
  margin-bottom: var(--space-2);
  border-radius: var(--radius-sm);
}

.skeleton-card {
  height: 400px;
  border-radius: var(--radius-lg);
}