/* ================================================================
   Navigation System Lab - NSL Theme CSS
   Sejong University Aerospace Engineering
   ================================================================ */

/* ----------------------------------------------------------------
   1. CSS VARIABLES & DESIGN TOKENS
   ---------------------------------------------------------------- */
:root {
  /* Brand Colors */
  --color-primary: #1a3a5c;
  --color-primary-dark: #0f2236;
  --color-primary-light: #2a5080;
  --color-secondary: #c8a951;
  --color-secondary-dark: #a8893a;
  --color-secondary-light: #e0c472;

  /* UI Colors */
  --color-bg: #f8f9fa;
  --color-bg-alt: #eef1f5;
  --color-surface: #ffffff;
  --color-border: #dee2e8;
  --color-border-light: #eceff4;

  /* Text */
  --color-text: #2c3e50;
  --color-text-light: #5a6a7a;
  --color-text-muted: #8a9ab0;
  --color-text-inverse: #ffffff;

  /* Accent Colors */
  --color-blue: #4a90d9;
  --color-teal: #2a9d8f;
  --color-green: #5cb85c;
  --color-red: #e74c3c;

  /* Gradients */
  --gradient-hero: linear-gradient(135deg, #0a1628 0%, #1a3a5c 40%, #0d2440 70%, #0a1220 100%);
  --gradient-card: linear-gradient(135deg, rgba(26,58,92,0.05) 0%, rgba(200,169,81,0.05) 100%);

  /* Typography */
  --font-sans: 'Inter', 'Noto Sans KR', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-korean: 'Noto Sans KR', sans-serif;

  --text-xs: 0.75rem;
  --text-sm: 0.875rem;
  --text-base: 1rem;
  --text-lg: 1.125rem;
  --text-xl: 1.25rem;
  --text-2xl: 1.5rem;
  --text-3xl: 1.875rem;
  --text-4xl: 2.25rem;
  --text-5xl: 3rem;

  --weight-light: 300;
  --weight-normal: 400;
  --weight-medium: 500;
  --weight-semibold: 600;
  --weight-bold: 700;

  --leading-tight: 1.25;
  --leading-snug: 1.375;
  --leading-normal: 1.5;
  --leading-relaxed: 1.625;

  /* 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;
  --space-20: 5rem;
  --space-24: 6rem;

  /* Border Radius */
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-xl: 16px;
  --radius-2xl: 24px;
  --radius-full: 9999px;

  /* Shadows */
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.08), 0 1px 2px rgba(0,0,0,0.06);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.10), 0 2px 6px rgba(0,0,0,0.06);
  --shadow-lg: 0 10px 30px rgba(0,0,0,0.12), 0 4px 12px rgba(0,0,0,0.08);
  --shadow-xl: 0 20px 50px rgba(0,0,0,0.15), 0 8px 20px rgba(0,0,0,0.10);
  --shadow-card-hover: 0 16px 40px rgba(26,58,92,0.16), 0 6px 16px rgba(26,58,92,0.10);

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-base: 250ms ease;
  --transition-slow: 400ms ease;

  /* Layout */
  --container-max: 1200px;
  --navbar-height: 72px;
}

/* ----------------------------------------------------------------
   2. RESET & BASE
   ---------------------------------------------------------------- */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  font-size: var(--text-base);
  line-height: var(--leading-normal);
  color: var(--color-text);
  background-color: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

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

a:hover {
  color: var(--color-primary-light);
}

ul, ol {
  list-style: none;
}

h1, h2, h3, h4, h5, h6 {
  font-weight: var(--weight-bold);
  line-height: var(--leading-tight);
  color: var(--color-text);
}

p {
  line-height: var(--leading-relaxed);
  color: var(--color-text-light);
}

address {
  font-style: normal;
}

button {
  cursor: pointer;
  border: none;
  background: none;
  font-family: inherit;
}

input, textarea, select {
  font-family: inherit;
}

/* ----------------------------------------------------------------
   3. LAYOUT UTILITIES
   ---------------------------------------------------------------- */
.container {
  max-width: var(--container-max);
  margin-inline: auto;
  padding-inline: var(--space-6);
}

.section {
  padding-block: var(--space-20);
}

/* ----------------------------------------------------------------
   4. TYPOGRAPHY
   ---------------------------------------------------------------- */
.section-tag {
  display: inline-block;
  font-size: var(--text-xs);
  font-weight: var(--weight-semibold);
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--color-secondary);
  background: rgba(200, 169, 81, 0.12);
  padding: var(--space-1) var(--space-3);
  border-radius: var(--radius-full);
  margin-bottom: var(--space-3);
}

.section-header {
  text-align: center;
  max-width: 640px;
  margin-inline: auto;
  margin-bottom: var(--space-12);
}

.section-title {
  font-size: var(--text-4xl);
  font-weight: var(--weight-bold);
  color: var(--color-primary);
  margin-bottom: var(--space-4);
  line-height: var(--leading-tight);
}

.section-desc {
  font-size: var(--text-lg);
  color: var(--color-text-light);
  line-height: var(--leading-relaxed);
}

.section-cta {
  text-align: center;
  margin-top: var(--space-12);
}

/* ----------------------------------------------------------------
   5. BUTTONS
   ---------------------------------------------------------------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-6);
  border-radius: var(--radius-md);
  font-size: var(--text-sm);
  font-weight: var(--weight-semibold);
  letter-spacing: 0.02em;
  transition: all var(--transition-base);
  cursor: pointer;
  border: 2px solid transparent;
  white-space: nowrap;
}

.btn-primary {
  background: var(--color-primary);
  color: var(--color-text-inverse);
  border-color: var(--color-primary);
}

.btn-primary:hover {
  background: var(--color-primary-dark);
  border-color: var(--color-primary-dark);
  color: var(--color-text-inverse);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

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

.btn-secondary:hover {
  background: var(--color-secondary-dark);
  border-color: var(--color-secondary-dark);
  color: var(--color-primary-dark);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.btn-outline {
  background: transparent;
  color: var(--color-primary);
  border-color: var(--color-primary);
}

.btn-outline:hover {
  background: var(--color-primary);
  color: var(--color-text-inverse);
  transform: translateY(-1px);
}

.btn-lg {
  padding: var(--space-4) var(--space-8);
  font-size: var(--text-base);
}

.btn-full {
  width: 100%;
  justify-content: center;
}

/* ----------------------------------------------------------------
   6. NAVBAR
   ---------------------------------------------------------------- */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--navbar-height);
  z-index: 1000;
  transition: background var(--transition-base), box-shadow var(--transition-base);
  background: rgba(10, 22, 40, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(255,255,255,0.08);
}

.navbar.scrolled {
  background: rgba(10, 22, 40, 0.97);
  box-shadow: 0 4px 24px rgba(0,0,0,0.25);
}

.nav-container {
  max-width: var(--container-max);
  margin-inline: auto;
  padding-inline: var(--space-6);
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  text-decoration: none;
  color: white;
  flex-shrink: 0;
}

.nav-logo:hover {
  color: var(--color-secondary-light);
}

.logo-badge {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  background: linear-gradient(135deg, var(--color-secondary) 0%, var(--color-secondary-dark) 100%);
  color: var(--color-primary-dark);
  font-size: var(--text-sm);
  font-weight: var(--weight-bold);
  letter-spacing: 0.05em;
  border-radius: var(--radius-md);
  flex-shrink: 0;
  box-shadow: 0 2px 8px rgba(200,169,81,0.3);
}

.logo-badge--sm {
  width: 36px;
  height: 36px;
  font-size: var(--text-xs);
}

.logo-text {
  display: flex;
  flex-direction: column;
}

.logo-title {
  font-size: var(--text-sm);
  font-weight: var(--weight-semibold);
  color: white;
  line-height: 1.2;
  letter-spacing: 0.01em;
}

.logo-subtitle {
  font-size: 10px;
  color: rgba(255,255,255,0.55);
  font-weight: var(--weight-normal);
  line-height: 1.3;
  font-family: var(--font-korean);
}

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

.nav-link {
  display: block;
  padding: var(--space-2) var(--space-3);
  font-size: var(--text-sm);
  font-weight: var(--weight-medium);
  color: rgba(255,255,255,0.8);
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
  position: relative;
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: 2px;
  left: 50%;
  transform: translateX(-50%) scaleX(0);
  width: calc(100% - var(--space-6));
  height: 2px;
  background: var(--color-secondary);
  border-radius: 1px;
  transition: transform var(--transition-base);
}

.nav-link:hover,
.nav-link.active {
  color: white;
}

.nav-link:hover::after,
.nav-link.active::after {
  transform: translateX(-50%) scaleX(1);
}

.nav-link.active {
  color: var(--color-secondary-light);
}

/* Mobile Toggle */
.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  padding: var(--space-2);
  cursor: pointer;
}

.nav-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: white;
  border-radius: 2px;
  transition: all var(--transition-base);
}

.nav-toggle.active span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

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

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

/* ----------------------------------------------------------------
   7. HERO SECTION
   ---------------------------------------------------------------- */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  padding-top: var(--navbar-height);
}

.hero-bg {
  position: absolute;
  inset: 0;
  background: var(--gradient-hero);
}

.stars {
  position: absolute;
  inset: 0;
  background-image:
    radial-gradient(1px 1px at 10% 15%, rgba(255,255,255,0.8) 0%, transparent 100%),
    radial-gradient(1px 1px at 25% 40%, rgba(255,255,255,0.6) 0%, transparent 100%),
    radial-gradient(1.5px 1.5px at 40% 8%, rgba(255,255,255,0.9) 0%, transparent 100%),
    radial-gradient(1px 1px at 55% 22%, rgba(255,255,255,0.7) 0%, transparent 100%),
    radial-gradient(1px 1px at 70% 55%, rgba(255,255,255,0.5) 0%, transparent 100%),
    radial-gradient(1.5px 1.5px at 85% 30%, rgba(255,255,255,0.8) 0%, transparent 100%),
    radial-gradient(1px 1px at 20% 75%, rgba(255,255,255,0.6) 0%, transparent 100%),
    radial-gradient(1px 1px at 50% 65%, rgba(255,255,255,0.4) 0%, transparent 100%),
    radial-gradient(1px 1px at 78% 80%, rgba(255,255,255,0.7) 0%, transparent 100%),
    radial-gradient(1.5px 1.5px at 92% 10%, rgba(255,255,255,0.9) 0%, transparent 100%),
    radial-gradient(1px 1px at 5% 50%, rgba(255,255,255,0.5) 0%, transparent 100%),
    radial-gradient(1px 1px at 35% 90%, rgba(255,255,255,0.6) 0%, transparent 100%),
    radial-gradient(1px 1px at 62% 45%, rgba(255,255,255,0.4) 0%, transparent 100%),
    radial-gradient(1.5px 1.5px at 15% 25%, rgba(200,169,81,0.4) 0%, transparent 100%),
    radial-gradient(2px 2px at 88% 62%, rgba(200,169,81,0.3) 0%, transparent 100%),
    radial-gradient(1px 1px at 45% 33%, rgba(255,255,255,0.7) 0%, transparent 100%),
    radial-gradient(1px 1px at 95% 48%, rgba(255,255,255,0.5) 0%, transparent 100%),
    radial-gradient(1px 1px at 30% 55%, rgba(255,255,255,0.6) 0%, transparent 100%),
    radial-gradient(1.5px 1.5px at 67% 15%, rgba(255,255,255,0.8) 0%, transparent 100%),
    radial-gradient(1px 1px at 8% 88%, rgba(255,255,255,0.5) 0%, transparent 100%);
}

.hero-overlay {
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse at 30% 50%, rgba(26,58,92,0.3) 0%, transparent 70%);
}

.hero-content {
  position: relative;
  text-align: center;
  padding: var(--space-20) var(--space-6);
  max-width: 900px;
  width: 100%;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  background: rgba(200,169,81,0.15);
  border: 1px solid rgba(200,169,81,0.3);
  color: var(--color-secondary-light);
  font-size: var(--text-xs);
  font-weight: var(--weight-semibold);
  letter-spacing: 0.1em;
  text-transform: uppercase;
  padding: var(--space-2) var(--space-4);
  border-radius: var(--radius-full);
  margin-bottom: var(--space-8);
  font-family: var(--font-korean);
}

.hero-badge-dot {
  width: 6px;
  height: 6px;
  background: var(--color-secondary);
  border-radius: 50%;
  animation: pulse-dot 2s infinite;
}

@keyframes pulse-dot {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.5; transform: scale(0.8); }
}

.hero-title {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-2);
  margin-bottom: var(--space-6);
}

.hero-title-ko {
  display: block;
  font-size: var(--text-5xl);
  font-weight: var(--weight-bold);
  color: var(--color-secondary);
  font-family: var(--font-korean);
  line-height: 1.1;
  text-shadow: 0 0 40px rgba(200,169,81,0.3);
}

.hero-title-en {
  display: block;
  font-size: var(--text-3xl);
  font-weight: var(--weight-medium);
  color: rgba(255,255,255,0.9);
  letter-spacing: 0.04em;
}

.hero-subtitle {
  font-size: var(--text-lg);
  color: rgba(255,255,255,0.65);
  line-height: var(--leading-relaxed);
  max-width: 700px;
  margin-inline: auto;
  margin-bottom: var(--space-10);
}

.hero-cta {
  display: flex;
  gap: var(--space-4);
  justify-content: center;
  flex-wrap: wrap;
  margin-bottom: var(--space-16);
}

.hero .btn-primary {
  background: var(--color-secondary);
  border-color: var(--color-secondary);
  color: var(--color-primary-dark);
  padding: var(--space-4) var(--space-8);
  font-size: var(--text-base);
}

.hero .btn-primary:hover {
  background: var(--color-secondary-light);
  border-color: var(--color-secondary-light);
  color: var(--color-primary-dark);
  box-shadow: 0 8px 24px rgba(200,169,81,0.4);
}

.hero .btn-outline {
  border-color: rgba(255,255,255,0.4);
  color: rgba(255,255,255,0.9);
  padding: var(--space-4) var(--space-8);
  font-size: var(--text-base);
}

.hero .btn-outline:hover {
  background: rgba(255,255,255,0.1);
  border-color: rgba(255,255,255,0.7);
  color: white;
}

.hero-stats {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-8);
  flex-wrap: wrap;
}

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

.stat-num {
  font-size: var(--text-3xl);
  font-weight: var(--weight-bold);
  color: var(--color-secondary);
  line-height: 1;
}

.stat-label {
  font-size: var(--text-xs);
  color: rgba(255,255,255,0.5);
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.stat-divider {
  width: 1px;
  height: 40px;
  background: rgba(255,255,255,0.15);
}

.hero-scroll-indicator {
  position: absolute;
  bottom: var(--space-8);
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-2);
  color: rgba(255,255,255,0.4);
  font-size: var(--text-xs);
  letter-spacing: 0.1em;
  text-transform: uppercase;
  animation: float 3s ease-in-out infinite;
}

@keyframes float {
  0%, 100% { transform: translateX(-50%) translateY(0); }
  50% { transform: translateX(-50%) translateY(-6px); }
}

.scroll-arrow {
  width: 18px;
  height: 18px;
  border-right: 2px solid rgba(255,255,255,0.3);
  border-bottom: 2px solid rgba(255,255,255,0.3);
  transform: rotate(45deg);
}

/* ----------------------------------------------------------------
   8. ANIMATIONS (CSS only)
   ---------------------------------------------------------------- */
.fade-in {
  opacity: 0;
  transform: translateY(20px);
  animation: fadeInUp 0.7s ease forwards;
}

.fade-in:nth-child(1) { animation-delay: 0.1s; }
.fade-in:nth-child(2) { animation-delay: 0.25s; }
.fade-in:nth-child(3) { animation-delay: 0.4s; }
.fade-in:nth-child(4) { animation-delay: 0.55s; }
.fade-in:nth-child(5) { animation-delay: 0.7s; }

@keyframes fadeInUp {
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.reveal {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ----------------------------------------------------------------
   9. CARDS
   ---------------------------------------------------------------- */
.cards-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-8);
}

.card {
  background: var(--color-surface);
  border-radius: var(--radius-xl);
  padding: var(--space-8);
  border: 1px solid var(--color-border-light);
  transition: all var(--transition-slow);
  position: relative;
  overflow: hidden;
}

.card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--color-primary), var(--color-secondary));
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--transition-slow);
}

.card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-card-hover);
  border-color: rgba(26,58,92,0.15);
}

.card:hover::before {
  transform: scaleX(1);
}

.card-icon {
  width: 72px;
  height: 72px;
  border-radius: var(--radius-lg);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: var(--space-6);
}

.card-icon--blue {
  background: rgba(74, 144, 217, 0.12);
  color: var(--color-blue);
}

.card-icon--gold {
  background: rgba(200, 169, 81, 0.12);
  color: var(--color-secondary);
}

.card-icon--teal {
  background: rgba(42, 157, 143, 0.12);
  color: var(--color-teal);
}

.card-title {
  font-size: var(--text-xl);
  font-weight: var(--weight-semibold);
  color: var(--color-primary);
  margin-bottom: var(--space-3);
}

.card-desc {
  font-size: var(--text-sm);
  line-height: var(--leading-relaxed);
  color: var(--color-text-light);
  margin-bottom: var(--space-5);
}

.card-link {
  font-size: var(--text-sm);
  font-weight: var(--weight-semibold);
  color: var(--color-primary);
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  transition: gap var(--transition-fast), color var(--transition-fast);
}

.card-link:hover {
  color: var(--color-secondary);
  gap: var(--space-2);
}

/* ----------------------------------------------------------------
   10. ABOUT SECTION
   ---------------------------------------------------------------- */
.about-section {
  background: linear-gradient(135deg, var(--color-primary-dark) 0%, var(--color-primary) 100%);
  color: white;
}

.about-section .section-tag {
  color: var(--color-secondary-light);
  background: rgba(200,169,81,0.15);
}

.about-section .section-title {
  color: white;
}

.about-section p {
  color: rgba(255,255,255,0.75);
}

.about-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-16);
  align-items: center;
}

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

.about-list {
  margin: var(--space-6) 0;
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.about-list li {
  display: flex;
  align-items: flex-start;
  gap: var(--space-3);
  font-size: var(--text-sm);
  color: rgba(255,255,255,0.8);
}

.about-list-icon {
  color: var(--color-secondary);
  font-weight: var(--weight-bold);
  flex-shrink: 0;
  margin-top: 2px;
}

/* Orbit Animation */
.about-visual {
  display: flex;
  justify-content: center;
  align-items: center;
}

.about-orbit-display {
  position: relative;
  width: 320px;
  height: 320px;
}

.orbit {
  position: absolute;
  border: 1px solid rgba(255,255,255,0.15);
  border-radius: 50%;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
}

.orbit-1 {
  width: 160px;
  height: 160px;
  animation: orbit-rotate 8s linear infinite;
}

.orbit-2 {
  width: 230px;
  height: 230px;
  animation: orbit-rotate 13s linear infinite reverse;
  border-style: dashed;
}

.orbit-3 {
  width: 300px;
  height: 300px;
  animation: orbit-rotate 18s linear infinite;
}

@keyframes orbit-rotate {
  from { transform: translate(-50%, -50%) rotate(0deg); }
  to { transform: translate(-50%, -50%) rotate(360deg); }
}

.satellite {
  position: absolute;
  top: -10px;
  left: 50%;
  transform: translateX(-50%);
}

.earth-center {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  text-align: center;
}

.earth-glow {
  position: absolute;
  inset: -20px;
  background: radial-gradient(circle, rgba(74,144,217,0.3) 0%, transparent 70%);
  border-radius: 50%;
  animation: glow-pulse 3s ease-in-out infinite;
}

@keyframes glow-pulse {
  0%, 100% { opacity: 0.6; transform: scale(1); }
  50% { opacity: 1; transform: scale(1.1); }
}

.earth-icon {
  font-size: 2.5rem;
  filter: drop-shadow(0 0 12px rgba(74,144,217,0.6));
}

.signal-line {
  position: absolute;
  top: 50%;
  left: 50%;
  width: 1px;
  background: linear-gradient(to top, rgba(200,169,81,0.6), transparent);
  transform-origin: bottom center;
}

.sl-1 {
  height: 80px;
  transform: translate(-50%, -100%) rotate(-30deg);
  animation: signal-flash 2s ease-in-out infinite;
}

.sl-2 {
  height: 115px;
  transform: translate(-50%, -100%) rotate(60deg);
  animation: signal-flash 2s ease-in-out 0.7s infinite;
}

.sl-3 {
  height: 150px;
  transform: translate(-50%, -100%) rotate(150deg);
  animation: signal-flash 2s ease-in-out 1.4s infinite;
}

@keyframes signal-flash {
  0%, 100% { opacity: 0.3; }
  50% { opacity: 1; }
}

/* ----------------------------------------------------------------
   11. NEWS SECTION
   ---------------------------------------------------------------- */
.news-section {
  background: var(--color-bg-alt);
}

.news-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-6);
}

.news-card {
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  border: 1px solid var(--color-border-light);
  transition: all var(--transition-base);
  display: flex;
  flex-direction: column;
}

.news-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
  border-color: rgba(26,58,92,0.15);
}

.news-meta {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  margin-bottom: var(--space-4);
}

.news-date {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  font-weight: var(--weight-medium);
}

.news-tag {
  font-size: var(--text-xs);
  font-weight: var(--weight-semibold);
  padding: 2px var(--space-2);
  border-radius: var(--radius-full);
  background: rgba(26,58,92,0.08);
  color: var(--color-primary);
}

.news-tag--announcement { background: rgba(200,169,81,0.12); color: var(--color-secondary-dark); }
.news-tag--publication { background: rgba(74,144,217,0.12); color: var(--color-blue); }
.news-tag--award { background: rgba(92,184,92,0.12); color: var(--color-green); }
.news-tag--event { background: rgba(42,157,143,0.12); color: var(--color-teal); }
.news-tag--alumni { background: rgba(155,89,182,0.12); color: #7b2d8e; }
.news-tag--press { background: rgba(41,128,185,0.12); color: #2471a3; }

.news-title {
  font-size: var(--text-lg);
  font-weight: var(--weight-semibold);
  color: var(--color-primary);
  margin-bottom: var(--space-3);
  line-height: var(--leading-snug);
  flex-grow: 1;
}

.news-title a {
  color: inherit;
  transition: color var(--transition-fast);
}

.news-title a:hover {
  color: var(--color-secondary);
}

.news-excerpt {
  font-size: var(--text-sm);
  color: var(--color-text-light);
  line-height: var(--leading-relaxed);
  margin-bottom: var(--space-4);
  flex-grow: 1;
}

.news-more {
  font-size: var(--text-sm);
  font-weight: var(--weight-semibold);
  color: var(--color-primary);
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  margin-top: auto;
  transition: gap var(--transition-fast), color var(--transition-fast);
}

.news-more:hover {
  color: var(--color-secondary);
  gap: var(--space-2);
}

/* ----------------------------------------------------------------
   12. CTA SECTION
   ---------------------------------------------------------------- */
.cta-section {
  padding-bottom: var(--space-24);
}

.cta-box {
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-light) 50%, #1e4a7a 100%);
  border-radius: var(--radius-2xl);
  padding: var(--space-16) var(--space-12);
  display: grid;
  grid-template-columns: 1fr auto;
  gap: var(--space-10);
  align-items: center;
  position: relative;
  overflow: hidden;
}

.cta-box::before {
  content: '';
  position: absolute;
  top: -50%;
  right: -10%;
  width: 400px;
  height: 400px;
  background: radial-gradient(circle, rgba(200,169,81,0.15) 0%, transparent 70%);
  pointer-events: none;
}

.cta-title {
  font-size: var(--text-3xl);
  font-weight: var(--weight-bold);
  color: white;
  margin-bottom: var(--space-4);
}

.cta-desc {
  font-size: var(--text-base);
  color: rgba(255,255,255,0.75);
  line-height: var(--leading-relaxed);
  margin-bottom: var(--space-8);
  max-width: 600px;
}

.cta-buttons {
  display: flex;
  gap: var(--space-4);
  flex-wrap: wrap;
}

.cta-box .btn-primary {
  background: var(--color-secondary);
  border-color: var(--color-secondary);
  color: var(--color-primary-dark);
}

.cta-box .btn-primary:hover {
  background: var(--color-secondary-light);
  border-color: var(--color-secondary-light);
}

.cta-box .btn-outline {
  border-color: rgba(255,255,255,0.4);
  color: white;
}

.cta-box .btn-outline:hover {
  background: rgba(255,255,255,0.12);
  border-color: rgba(255,255,255,0.7);
}

.cta-visual {
  display: flex;
  align-items: center;
  justify-content: center;
}

.cta-icon-group {
  position: relative;
  width: 120px;
  height: 120px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.cta-icon-big {
  font-size: 4rem;
  position: relative;
  z-index: 1;
  filter: drop-shadow(0 0 20px rgba(200,169,81,0.4));
  animation: float 4s ease-in-out infinite;
}

.cta-icon-ring {
  position: absolute;
  inset: 0;
  border: 2px solid rgba(200,169,81,0.3);
  border-radius: 50%;
  animation: ring-pulse 3s ease-in-out infinite;
}

@keyframes ring-pulse {
  0%, 100% { transform: scale(1); opacity: 0.5; }
  50% { transform: scale(1.2); opacity: 0.2; }
}

/* ----------------------------------------------------------------
   13. PAGE HEADER
   ---------------------------------------------------------------- */
.page-header {
  background: linear-gradient(135deg, var(--color-primary-dark) 0%, var(--color-primary) 100%);
  padding-top: calc(var(--navbar-height) + var(--space-16));
  padding-bottom: var(--space-16);
  position: relative;
  overflow: hidden;
}

.page-header::before {
  content: '';
  position: absolute;
  inset: 0;
  background-image:
    radial-gradient(1px 1px at 15% 20%, rgba(255,255,255,0.4) 0%, transparent 100%),
    radial-gradient(1px 1px at 50% 60%, rgba(255,255,255,0.3) 0%, transparent 100%),
    radial-gradient(1px 1px at 80% 25%, rgba(255,255,255,0.4) 0%, transparent 100%),
    radial-gradient(1px 1px at 35% 80%, rgba(255,255,255,0.2) 0%, transparent 100%),
    radial-gradient(1px 1px at 70% 75%, rgba(255,255,255,0.3) 0%, transparent 100%);
  pointer-events: none;
}

.breadcrumb {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  margin-bottom: var(--space-4);
  font-size: var(--text-sm);
}

.breadcrumb a {
  color: rgba(255,255,255,0.6);
  transition: color var(--transition-fast);
}

.breadcrumb a:hover {
  color: var(--color-secondary-light);
}

.breadcrumb-sep {
  color: rgba(255,255,255,0.3);
  font-size: var(--text-base);
}

.breadcrumb-current {
  color: var(--color-secondary-light);
  font-weight: var(--weight-medium);
}

.page-title {
  font-size: var(--text-4xl);
  font-weight: var(--weight-bold);
  color: white;
  margin-bottom: var(--space-3);
}

.page-intro-text,
.page-meta {
  font-size: var(--text-base);
  color: rgba(255,255,255,0.7);
}

.page-meta {
  display: flex;
  gap: var(--space-4);
  font-size: var(--text-sm);
}

/* ----------------------------------------------------------------
   14. ARTICLE CONTENT
   ---------------------------------------------------------------- */
.content-layout {
  max-width: 800px;
  margin-inline: auto;
  padding-block: var(--space-16);
}

.article-content h1, .article-content h2, .article-content h3 {
  color: var(--color-primary);
  margin-bottom: var(--space-4);
  margin-top: var(--space-8);
}

.article-content h1 { font-size: var(--text-3xl); }
.article-content h2 { font-size: var(--text-2xl); }
.article-content h3 { font-size: var(--text-xl); }

.article-content p {
  margin-bottom: var(--space-4);
  line-height: var(--leading-relaxed);
}

.article-content ul, .article-content ol {
  list-style: disc;
  padding-left: var(--space-8);
  margin-bottom: var(--space-4);
}

.article-content ol { list-style: decimal; }

.article-content li {
  margin-bottom: var(--space-2);
  line-height: var(--leading-relaxed);
  color: var(--color-text-light);
}

.article-content strong { color: var(--color-text); font-weight: var(--weight-semibold); }
.article-content em { font-style: italic; }

.article-content img {
  display: block;
  max-width: 100%;
  height: auto;
  margin: var(--space-6) auto;
  border-radius: var(--radius-md);
}

.article-content p:has(> img:only-child) {
  text-align: center;
}

.article-content blockquote {
  border-left: 4px solid var(--color-secondary);
  padding-left: var(--space-6);
  margin: var(--space-6) 0;
  color: var(--color-text-light);
  font-style: italic;
}

/* ----------------------------------------------------------------
   15. LIST PAGE
   ---------------------------------------------------------------- */
.list-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-8);
}

.list-card {
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: var(--space-8);
  border: 1px solid var(--color-border-light);
  transition: all var(--transition-base);
}

.list-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
}

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

.list-card-date {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
}

.list-card-tag {
  font-size: var(--text-xs);
  font-weight: var(--weight-semibold);
  padding: 2px var(--space-2);
  border-radius: var(--radius-full);
  background: rgba(26,58,92,0.08);
  color: var(--color-primary);
}

.list-card-title {
  font-size: var(--text-xl);
  font-weight: var(--weight-semibold);
  margin-bottom: var(--space-3);
}

.list-card-title a {
  color: var(--color-primary);
  transition: color var(--transition-fast);
}

.list-card-title a:hover {
  color: var(--color-secondary);
}

.list-card-summary {
  font-size: var(--text-sm);
  color: var(--color-text-light);
  line-height: var(--leading-relaxed);
  margin-bottom: var(--space-4);
}

/* ----------------------------------------------------------------
   16. MEMBERS PAGE
   ---------------------------------------------------------------- */
.professor-section {
  margin-bottom: var(--space-20);
}

.members-section-title {
  font-size: var(--text-2xl);
  color: var(--color-primary);
  margin-bottom: var(--space-8);
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding-bottom: var(--space-4);
  border-bottom: 2px solid var(--color-border);
}

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

.professor-card {
  background: var(--color-surface);
  border-radius: var(--radius-xl);
  padding: var(--space-10);
  border: 1px solid var(--color-border-light);
  display: grid;
  grid-template-columns: 200px 1fr;
  gap: var(--space-10);
  box-shadow: var(--shadow-md);
  transition: box-shadow var(--transition-base);
}

.professor-card:hover {
  box-shadow: var(--shadow-lg);
}

.photo-placeholder {
  width: 120px;
  height: 140px;
  background: linear-gradient(135deg, var(--color-primary), var(--color-primary-light));
  border-radius: var(--radius-lg);
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-size: var(--text-2xl);
  font-weight: var(--weight-bold);
}

.photo-placeholder--lg {
  width: 180px;
  height: 210px;
  font-size: var(--text-3xl);
}

.professor-photo img,
.professor-photo .photo-placeholder--lg {
  border-radius: var(--radius-lg);
}

.professor-name {
  font-size: var(--text-3xl);
  color: var(--color-primary);
  margin-bottom: var(--space-1);
}

.professor-name-ko {
  font-size: var(--text-xl);
  color: var(--color-text-light);
  font-family: var(--font-korean);
  margin-bottom: var(--space-2);
}

.professor-position {
  font-size: var(--text-lg);
  color: var(--color-secondary-dark);
  font-weight: var(--weight-medium);
  margin-bottom: var(--space-2);
}

.professor-dept {
  font-size: var(--text-base);
  color: var(--color-text-light);
  margin-bottom: var(--space-4);
}

.professor-email a {
  color: var(--color-primary);
  font-weight: var(--weight-medium);
}

.professor-detail {
  font-size: var(--text-sm);
  color: var(--color-text-light);
  margin-bottom: var(--space-2);
}

.professor-detail strong {
  color: var(--color-text);
}

.professor-links {
  display: flex;
  gap: var(--space-3);
  flex-wrap: wrap;
  margin-top: var(--space-5);
}

.prof-link {
  display: inline-block;
  padding: var(--space-2) var(--space-4);
  background: rgba(26,58,92,0.06);
  color: var(--color-primary);
  border-radius: var(--radius-full);
  font-size: var(--text-xs);
  font-weight: var(--weight-semibold);
  transition: all var(--transition-fast);
  border: 1px solid rgba(26,58,92,0.12);
}

.prof-link:hover {
  background: var(--color-primary);
  color: white;
  border-color: var(--color-primary);
}

/* Members Grid */
.members-group {
  margin-bottom: var(--space-16);
}

.members-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-6);
}

.member-card {
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  border: 1px solid var(--color-border-light);
  text-align: center;
  transition: all var(--transition-base);
}

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

.member-photo {
  display: flex;
  justify-content: center;
  margin-bottom: var(--space-4);
}

.member-photo img,
.member-photo .photo-placeholder {
  border-radius: 50%;
  object-fit: cover;
}

.member-photo .photo-placeholder {
  width: 80px;
  height: 80px;
  font-size: var(--text-lg);
}

.member-name {
  font-size: var(--text-base);
  font-weight: var(--weight-semibold);
  color: var(--color-primary);
  margin-bottom: var(--space-1);
}

.member-name-ko {
  font-size: var(--text-sm);
  color: var(--color-text-light);
  font-family: var(--font-korean);
  margin-bottom: var(--space-2);
}

.member-role-label {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  font-weight: var(--weight-medium);
  margin-bottom: var(--space-2);
  letter-spacing: 0.03em;
}

.member-research {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  line-height: var(--leading-relaxed);
  margin-bottom: var(--space-3);
}

.member-research-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-bottom: var(--space-3);
}

.research-tag {
  font-size: 0.7rem;
  padding: 3px 10px;
  background: rgba(26,58,92,0.06);
  color: var(--color-text-muted);
  border-radius: var(--radius-full);
  white-space: nowrap;
}

.research-tag--linked {
  background: rgba(26,58,92,0.1);
  color: var(--color-primary);
  text-decoration: none;
  cursor: pointer;
  transition: background 0.2s, color 0.2s;
}

.research-tag--linked:hover {
  background: var(--color-primary);
  color: #fff;
}

.member-email {
  font-size: var(--text-xs);
  color: var(--color-primary);
  word-break: break-all;
}

/* Alumni */
.alumni-list {
  display: flex;
  flex-direction: column;
  gap: 0;
}

.alumni-year-heading {
  font-size: var(--text-lg);
  font-weight: var(--weight-bold);
  color: var(--color-primary);
  padding: var(--space-4) 0 var(--space-2);
  margin-top: var(--space-4);
  border-bottom: 2px solid var(--color-primary);
}

.alumni-year-heading:first-child {
  margin-top: 0;
}

.alumni-item {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
  padding: var(--space-3) var(--space-4);
  border-bottom: 1px solid var(--color-border-light);
  font-size: var(--text-sm);
}

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

.alumni-name {
  font-weight: var(--weight-semibold);
  color: var(--color-heading);
}

.alumni-degree {
  font-size: var(--text-xs);
  padding: 2px 8px;
  background: rgba(26,58,92,0.08);
  color: var(--color-primary);
  border-radius: var(--radius-full);
}

.alumni-thesis {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  margin: 0;
  padding-left: var(--space-1);
}

.alumni-position {
  font-size: var(--text-xs);
  color: var(--color-text-light);
  margin: 0;
  padding-left: var(--space-1);
}

.alumni-position::before {
  content: "\2192 ";
  color: var(--color-accent);
}

/* Join Us */
.join-section {
  margin-top: var(--space-12);
}

.join-box {
  background: linear-gradient(135deg, var(--color-primary), var(--color-primary-light));
  border-radius: var(--radius-xl);
  padding: var(--space-12) var(--space-10);
  text-align: center;
  color: white;
}

.join-box h3 {
  font-size: var(--text-2xl);
  color: white;
  margin-bottom: var(--space-4);
}

.join-box p {
  color: rgba(255,255,255,0.75);
  max-width: 500px;
  margin-inline: auto;
  margin-bottom: var(--space-8);
}

/* ----------------------------------------------------------------
   17. PUBLICATIONS PAGE
   ---------------------------------------------------------------- */

/* Stats bar */
.pub-stats {
  display: flex;
  gap: var(--space-6);
  margin-bottom: var(--space-10);
  padding: var(--space-6) var(--space-8);
  background: linear-gradient(135deg, #0f2744 0%, #1a3a5c 100%);
  border-radius: var(--radius-xl);
}

.pub-stat-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  flex: 1;
}

.pub-stat-num {
  font-size: var(--text-3xl);
  font-weight: var(--weight-bold);
  color: #e8c96a;
  line-height: 1;
  margin-bottom: var(--space-1);
}

.pub-stat-label {
  font-size: var(--text-xs);
  color: rgba(255,255,255,0.65);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-weight: var(--weight-medium);
}

/* Section tabs */
.pub-tabs {
  display: flex;
  gap: var(--space-2);
  margin-bottom: var(--space-10);
  flex-wrap: wrap;
  border-bottom: 2px solid var(--color-border);
  padding-bottom: 0;
}

.pub-tab {
  padding: var(--space-3) var(--space-6);
  font-size: var(--text-sm);
  font-weight: var(--weight-semibold);
  color: var(--color-text-light);
  background: none;
  border: none;
  border-bottom: 3px solid transparent;
  margin-bottom: -2px;
  cursor: pointer;
  transition: color var(--transition-fast), border-color var(--transition-fast);
  white-space: nowrap;
}

.pub-tab:hover {
  color: var(--color-primary);
}

.pub-tab.active {
  color: var(--color-primary);
  border-bottom-color: var(--color-primary);
}

/* Section visibility */
.pub-section { display: none; }
.pub-section.active { display: block; }

/* Year groups */
.pub-year-group {
  margin-bottom: var(--space-10);
}

.pub-year {
  font-size: var(--text-2xl);
  font-weight: var(--weight-bold);
  color: var(--color-primary);
  margin-bottom: var(--space-5);
  padding-bottom: var(--space-2);
  border-bottom: 3px solid var(--color-secondary);
  display: inline-block;
}

/* Data list */
.pub-data-list {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  counter-reset: pub-counter;
}

/* Individual row */
.pub-row {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: var(--space-4);
  padding: var(--space-4) var(--space-5);
  background: var(--color-surface);
  border-radius: var(--radius-md);
  border-left: 3px solid var(--color-primary);
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
  counter-increment: pub-counter;
}

.pub-row::before {
  content: counter(pub-counter) ".";
  flex-shrink: 0;
  width: 28px;
  font-size: var(--text-xs);
  font-weight: var(--weight-semibold);
  color: var(--color-text-muted);
  padding-top: 2px;
}

.pub-row:hover {
  border-left-color: var(--color-secondary);
  box-shadow: var(--shadow-sm);
}

.pub-row-body {
  flex: 1;
  min-width: 0;
}

.pub-title-text {
  display: block;
  font-size: var(--text-sm);
  font-weight: var(--weight-medium);
  color: var(--color-primary);
  line-height: var(--leading-relaxed);
  margin-bottom: var(--space-1);
}

.pub-venue {
  display: block;
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  font-style: italic;
  line-height: var(--leading-normal);
}

/* Right-side meta */
.pub-row-meta {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  flex-shrink: 0;
}

.pub-year-tag {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  font-weight: var(--weight-medium);
  white-space: nowrap;
}

/* Scope badges */
.scope-badge {
  display: inline-block;
  padding: 2px 8px;
  border-radius: 9999px;
  font-size: 0.65rem;
  font-weight: var(--weight-bold);
  letter-spacing: 0.03em;
  white-space: nowrap;
  line-height: 1.5;
}

.scope-intl {
  background: rgba(26,58,92,0.10);
  color: var(--color-primary);
}

.scope-domestic {
  background: rgba(0,0,0,0.04);
  color: var(--color-text-muted);
}

/* Status badges (patents) */
.status-badge {
  display: inline-block;
  padding: 2px 8px;
  border-radius: 9999px;
  font-size: 0.65rem;
  font-weight: var(--weight-bold);
  letter-spacing: 0.03em;
  white-space: nowrap;
  line-height: 1.5;
}

.status-granted {
  background: rgba(34,139,84,0.12);
  color: #1a7a48;
}

.status-filed {
  background: rgba(200,169,81,0.14);
  color: #9a7e2e;
}

/* ----------------------------------------------------------------
   18. RESEARCH PAGE
   ---------------------------------------------------------------- */
.research-section-heading {
  font-size: var(--text-2xl);
  color: var(--color-primary);
  margin-bottom: var(--space-8);
  padding-bottom: var(--space-3);
  border-bottom: 2px solid var(--color-border);
}

.research-areas-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-8);
  margin-bottom: var(--space-16);
}

.research-card {
  background: var(--color-surface);
  border-radius: var(--radius-xl);
  padding: var(--space-8);
  border: 1px solid var(--color-border-light);
  transition: all var(--transition-slow);
  position: relative;
  overflow: hidden;
}

.research-card::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--color-secondary), var(--color-primary));
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--transition-slow);
}

.research-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-card-hover);
}

.research-card:hover::after {
  transform: scaleX(1);
}

.research-card-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  margin-bottom: var(--space-5);
}

.research-icon-wrap {
  width: 64px;
  height: 64px;
  background: linear-gradient(135deg, rgba(26,58,92,0.08), rgba(200,169,81,0.08));
  border-radius: var(--radius-lg);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-primary);
}

.research-funding-badge {
  font-size: var(--text-xs);
  font-weight: var(--weight-semibold);
  padding: var(--space-1) var(--space-3);
  background: rgba(200,169,81,0.12);
  color: var(--color-secondary-dark);
  border-radius: var(--radius-full);
}

.research-card-title {
  font-size: var(--text-xl);
  font-weight: var(--weight-semibold);
  color: var(--color-primary);
  margin-bottom: var(--space-1);
}

.research-card-title-ko {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  font-family: var(--font-korean);
  margin-bottom: var(--space-4);
}

.research-card-desc {
  font-size: var(--text-sm);
  line-height: var(--leading-relaxed);
  color: var(--color-text-light);
  margin-bottom: var(--space-5);
}

.research-card-topics {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  margin-bottom: var(--space-5);
}

.topic-tag {
  font-size: var(--text-xs);
  padding: var(--space-1) var(--space-3);
  background: rgba(26,58,92,0.06);
  color: var(--color-primary);
  border-radius: var(--radius-full);
  border: 1px solid rgba(26,58,92,0.10);
  font-weight: var(--weight-medium);
}

/* Funding */
.funding-section {
  margin-top: var(--space-16);
  padding-top: var(--space-12);
  border-top: 1px solid var(--color-border);
}

.funding-intro {
  font-size: var(--text-base);
  color: var(--color-text-light);
  margin-bottom: var(--space-8);
}

.funding-logos {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-6);
}

.funding-item {
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  text-align: center;
  border: 1px solid var(--color-border-light);
  transition: all var(--transition-base);
}

.funding-item:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
}

.funding-badge {
  width: 64px;
  height: 64px;
  background: linear-gradient(135deg, var(--color-primary), var(--color-primary-light));
  color: white;
  font-size: var(--text-sm);
  font-weight: var(--weight-bold);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto var(--space-3);
}

.funding-item span {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  line-height: var(--leading-normal);
}

/* ----------------------------------------------------------------
   19. NEWS LIST PAGE
   ---------------------------------------------------------------- */
.news-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-6);
}

.news-list-item {
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: var(--space-6) var(--space-8);
  border: 1px solid var(--color-border-light);
  display: grid;
  grid-template-columns: 80px 1fr;
  gap: var(--space-8);
  align-items: start;
  transition: all var(--transition-base);
}

.news-list-item:hover {
  transform: translateX(4px);
  box-shadow: var(--shadow-md);
  border-color: rgba(26,58,92,0.15);
}

.news-list-date {
  text-align: center;
  padding: var(--space-4) var(--space-3);
  background: var(--color-bg-alt);
  border-radius: var(--radius-md);
  display: flex;
  flex-direction: column;
  align-items: center;
}

.news-day {
  font-size: var(--text-3xl);
  font-weight: var(--weight-bold);
  color: var(--color-primary);
  line-height: 1;
}

.news-month {
  font-size: var(--text-sm);
  font-weight: var(--weight-semibold);
  color: var(--color-secondary-dark);
  text-transform: uppercase;
}

.news-year-sm {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
}

.news-list-meta {
  margin-bottom: var(--space-2);
}

.news-list-title {
  font-size: var(--text-xl);
  font-weight: var(--weight-semibold);
  margin-bottom: var(--space-3);
}

.news-list-title a {
  color: var(--color-primary);
  transition: color var(--transition-fast);
}

.news-list-title a:hover {
  color: var(--color-secondary);
}

.news-list-summary {
  font-size: var(--text-sm);
  color: var(--color-text-light);
  line-height: var(--leading-relaxed);
  margin-bottom: var(--space-3);
}

/* ----------------------------------------------------------------
   20. CONTACT PAGE
   ---------------------------------------------------------------- */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1.5fr;
  gap: var(--space-12);
  margin-top: var(--space-8);
}

.contact-section-title {
  font-size: var(--text-2xl);
  color: var(--color-primary);
  margin-bottom: var(--space-8);
  padding-bottom: var(--space-3);
  border-bottom: 2px solid var(--color-border);
}

.contact-item {
  display: flex;
  align-items: flex-start;
  gap: var(--space-5);
  margin-bottom: var(--space-8);
}

.contact-icon {
  font-size: 1.5rem;
  flex-shrink: 0;
  width: 44px;
  height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(26,58,92,0.07);
  border-radius: var(--radius-md);
}

.contact-detail h4 {
  font-size: var(--text-sm);
  font-weight: var(--weight-semibold);
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-bottom: var(--space-1);
}

.contact-detail p {
  font-size: var(--text-sm);
  color: var(--color-text);
  line-height: var(--leading-relaxed);
  margin-bottom: var(--space-1);
}

.contact-ko {
  font-family: var(--font-korean);
  font-size: var(--text-xs) !important;
  color: var(--color-text-muted) !important;
}

.contact-detail a {
  color: var(--color-primary);
  font-weight: var(--weight-medium);
}

/* Map block */
.map-placeholder {
  background: linear-gradient(135deg, #1a3a5c 0%, #22487a 100%);
  border-radius: var(--radius-xl);
  padding: var(--space-8) var(--space-10);
  margin-bottom: var(--space-8);
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
}

.map-inner {
  display: flex;
  flex-direction: column;
  align-items: center;
  margin-bottom: var(--space-5);
}

.map-pin {
  font-size: 2.5rem;
  margin-bottom: var(--space-3);
  filter: drop-shadow(0 4px 12px rgba(200,169,81,0.4));
}

.map-label {
  color: white;
  font-size: var(--text-base);
  line-height: var(--leading-relaxed);
}

.map-label strong {
  color: #e8c96a;
  font-size: var(--text-lg);
}

.map-note-list {
  list-style: none;
  padding: 0;
  margin: 0;
  width: 100%;
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  text-align: left;
}

.map-note-list li {
  font-size: var(--text-sm);
  color: rgba(255,255,255,0.92);
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.transport-badge {
  display: inline-block;
  padding: 2px 8px;
  border-radius: 9999px;
  font-size: 0.7rem;
  font-weight: var(--weight-semibold);
  white-space: nowrap;
  flex-shrink: 0;
}

.transport-badge.subway { background: #2b7a3e; color: #fff; }
.transport-badge.bus    { background: #1a5cbf; color: #fff; }
.transport-badge.car    { background: rgba(255,255,255,0.15); color: rgba(255,255,255,0.85); }

/* Contact Form */
.contact-form-section h3 {
  font-size: var(--text-xl);
  color: var(--color-primary);
  margin-bottom: var(--space-6);
}

.contact-form {
  display: flex;
  flex-direction: column;
  gap: var(--space-5);
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.form-group label {
  font-size: var(--text-sm);
  font-weight: var(--weight-medium);
  color: var(--color-text);
}

.form-group input,
.form-group select,
.form-group textarea {
  padding: var(--space-3) var(--space-4);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  font-size: var(--text-sm);
  color: var(--color-text);
  background: var(--color-surface);
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
  width: 100%;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(26,58,92,0.1);
}

.form-group textarea {
  resize: vertical;
  min-height: 120px;
}

/* ----------------------------------------------------------------
   20b. PROSPECTIVE STUDENTS CTA
   ---------------------------------------------------------------- */
.prospective-cta {
  background: linear-gradient(135deg, #0f2744 0%, #1a3a5c 60%, #1e4570 100%);
  padding: var(--space-16) 0;
  margin-top: var(--space-12);
}

.cta-inner {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-16);
  align-items: center;
}

.cta-badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  background: rgba(200,169,81,0.18);
  border: 1px solid rgba(200,169,81,0.4);
  color: #e8c96a;
  font-size: var(--text-sm);
  font-weight: var(--weight-semibold);
  padding: var(--space-1) var(--space-4);
  border-radius: 9999px;
  margin-bottom: var(--space-4);
  letter-spacing: 0.04em;
}

.cta-title {
  font-size: var(--text-3xl);
  font-weight: var(--weight-bold);
  color: #ffffff;
  margin-bottom: var(--space-4);
  line-height: var(--leading-tight);
}

.cta-desc {
  font-size: var(--text-sm);
  color: rgba(255,255,255,0.7);
  line-height: var(--leading-relaxed);
  margin-bottom: var(--space-8);
}

.cta-btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  background: #c8a951;
  color: #0f2744;
  font-size: var(--text-sm);
  font-weight: var(--weight-bold);
  padding: var(--space-3) var(--space-7);
  border-radius: var(--radius-md);
  text-decoration: none;
  transition: background var(--transition-fast), transform var(--transition-fast);
  letter-spacing: 0.02em;
}

.cta-btn:hover {
  background: #e0bb60;
  transform: translateY(-2px);
}

.cta-skills {
  background: rgba(255,255,255,0.05);
  border: 1px solid rgba(255,255,255,0.1);
  border-radius: var(--radius-xl);
  padding: var(--space-8) var(--space-10);
}

.cta-skills-title {
  font-size: var(--text-sm);
  font-weight: var(--weight-semibold);
  color: #e8c96a;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: var(--space-5);
}

.cta-skills-list {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.cta-skills-list li {
  font-size: var(--text-sm);
  color: rgba(255,255,255,0.82);
  line-height: var(--leading-normal);
  padding-left: var(--space-1);
}

/* ----------------------------------------------------------------
   21. FOOTER
   ---------------------------------------------------------------- */
.footer {
  background: linear-gradient(135deg, #0a1628 0%, #0d1e34 100%);
  color: rgba(255,255,255,0.65);
  padding-top: var(--space-16);
}

.footer-container {
  max-width: var(--container-max);
  margin-inline: auto;
  padding-inline: var(--space-6);
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1.5fr;
  gap: var(--space-12);
  padding-bottom: var(--space-12);
  border-bottom: 1px solid rgba(255,255,255,0.08);
}

.footer-logo {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  margin-bottom: var(--space-5);
}

.footer-lab-name {
  font-size: var(--text-base);
  font-weight: var(--weight-semibold);
  color: white;
  line-height: 1.2;
}

.footer-lab-name-ko {
  font-size: var(--text-sm);
  color: rgba(255,255,255,0.5);
  font-family: var(--font-korean);
  line-height: 1.3;
}

.footer-desc {
  font-size: var(--text-sm);
  line-height: var(--leading-relaxed);
  color: rgba(255,255,255,0.5);
  margin: 0;
}

.footer-heading {
  font-size: var(--text-sm);
  font-weight: var(--weight-semibold);
  color: var(--color-secondary-light);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  margin-bottom: var(--space-5);
}

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

.footer-links a {
  font-size: var(--text-sm);
  color: rgba(255,255,255,0.55);
  transition: color var(--transition-fast);
}

.footer-links a:hover {
  color: var(--color-secondary-light);
}

.footer-address {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}

.footer-address p {
  font-size: var(--text-sm);
  color: rgba(255,255,255,0.55);
  line-height: var(--leading-relaxed);
  display: flex;
  align-items: flex-start;
  gap: var(--space-3);
  margin: 0;
}

.footer-icon {
  flex-shrink: 0;
  font-size: var(--text-base);
  margin-top: 1px;
}

.footer-address a {
  color: rgba(255,255,255,0.55);
}

.footer-address a:hover {
  color: var(--color-secondary-light);
}

.footer-bottom {
  padding-block: var(--space-6);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
  flex-wrap: wrap;
}

.footer-bottom p {
  font-size: var(--text-xs);
  color: rgba(255,255,255,0.35);
  margin: 0;
}

.footer-bottom-ko {
  font-family: var(--font-korean);
}

/* ----------------------------------------------------------------
   22. EMPTY STATE
   ---------------------------------------------------------------- */
.empty-state {
  text-align: center;
  padding: var(--space-20);
  color: var(--color-text-muted);
}

/* ----------------------------------------------------------------
   23. RESPONSIVE - TABLET (768px)
   ---------------------------------------------------------------- */
@media (max-width: 1024px) {
  .cards-grid {
    grid-template-columns: 1fr 1fr;
  }

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

  .funding-logos {
    grid-template-columns: repeat(2, 1fr);
  }

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

  .footer-col:first-child {
    grid-column: span 2;
  }
}

@media (max-width: 768px) {
  :root {
    --navbar-height: 64px;
  }

  /* Mobile nav */
  .nav-toggle {
    display: flex;
  }

  .nav-menu {
    position: fixed;
    top: var(--navbar-height);
    left: 0;
    right: 0;
    background: rgba(10,22,40,0.98);
    backdrop-filter: blur(16px);
    flex-direction: column;
    align-items: stretch;
    padding: var(--space-6);
    gap: var(--space-1);
    transform: translateY(-110%);
    opacity: 0;
    transition: transform var(--transition-base), opacity var(--transition-base);
    border-bottom: 1px solid rgba(255,255,255,0.1);
  }

  .nav-menu.open {
    transform: translateY(0);
    opacity: 1;
  }

  .nav-link {
    padding: var(--space-4) var(--space-4);
    border-radius: var(--radius-md);
    font-size: var(--text-base);
  }

  .nav-link::after {
    display: none;
  }

  .nav-link:hover,
  .nav-link.active {
    background: rgba(255,255,255,0.08);
  }

  /* Hero */
  .hero-title-ko { font-size: var(--text-4xl); }
  .hero-title-en { font-size: var(--text-2xl); }
  .hero-subtitle { font-size: var(--text-base); }
  .hero-stats { gap: var(--space-6); }
  .stat-divider { height: 28px; }

  /* Sections */
  .section { padding-block: var(--space-16); }
  .section-title { font-size: var(--text-3xl); }

  /* Grids */
  .cards-grid,
  .news-grid,
  .research-areas-grid,
  .list-grid { grid-template-columns: 1fr; }

  .about-grid { grid-template-columns: 1fr; }
  .about-visual { display: none; }

  .cta-box {
    grid-template-columns: 1fr;
    padding: var(--space-10) var(--space-8);
    text-align: center;
  }

  .cta-visual { display: none; }

  .professor-card {
    grid-template-columns: 1fr;
    text-align: center;
  }

  .professor-photo {
    display: flex;
    justify-content: center;
  }

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

  .members-grid { grid-template-columns: repeat(2, 1fr); }
  .alumni-list { grid-template-columns: 1fr; }

  .news-list-item {
    grid-template-columns: 60px 1fr;
    gap: var(--space-4);
  }

  .contact-grid { grid-template-columns: 1fr; }
  .cta-inner { grid-template-columns: 1fr; gap: var(--space-8); }
  .cta-title { font-size: var(--text-2xl); }

  .funding-logos { grid-template-columns: repeat(2, 1fr); }

  .footer-grid { grid-template-columns: 1fr; }
  .footer-col:first-child { grid-column: auto; }

  .footer-bottom {
    flex-direction: column;
    text-align: center;
  }

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

  .pub-year-group {
    overflow-x: auto;
  }

  .pub-stats {
    gap: var(--space-3);
    padding: var(--space-5) var(--space-4);
  }

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

  .pub-tabs {
    gap: 0;
  }

  .pub-tab {
    padding: var(--space-2) var(--space-3);
    font-size: var(--text-xs);
  }

  .pub-row {
    flex-direction: column;
    gap: var(--space-2);
  }

  .pub-row-meta {
    padding-left: 28px;
  }
}

@media (max-width: 480px) {
  :root {
    --space-20: 3rem;
    --space-16: 2.5rem;
  }

  .hero-title-ko { font-size: var(--text-3xl); }
  .hero-title-en { font-size: var(--text-xl); }

  .hero-cta {
    flex-direction: column;
    align-items: center;
  }

  .hero-stats {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--space-4);
  }

  .stat-divider { display: none; }

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

  .logo-text { display: none; }

  .container { padding-inline: var(--space-4); }

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

/* ----------------------------------------------------------------
   24. PAGINATION
   ---------------------------------------------------------------- */
.pagination {
  margin-top: var(--space-12);
  display: flex;
  justify-content: center;
}

.pagination-list {
  display: flex;
  list-style: none;
  padding: 0;
  margin: 0;
  gap: 0.35rem;
  align-items: center;
  flex-wrap: wrap;
  justify-content: center;
}

.pagination-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 2.5rem;
  height: 2.5rem;
  padding: 0 0.75rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--white);
  color: var(--text);
  font-size: var(--text-sm);
  font-weight: 500;
  text-decoration: none;
  transition: all var(--transition);
}

.pagination-link:hover:not(.pagination-disabled):not(.pagination-current) {
  background: var(--primary);
  border-color: var(--primary);
  color: var(--white);
}

.pagination-current {
  background: var(--primary);
  border-color: var(--primary);
  color: var(--white);
  font-weight: 700;
}

.pagination-disabled {
  opacity: 0.4;
  cursor: default;
  pointer-events: none;
}

.pagination-prev,
.pagination-next {
  font-size: var(--text-xs);
  letter-spacing: 0.02em;
}

@media (max-width: 640px) {
  .pagination-link {
    min-width: 2rem;
    height: 2rem;
    padding: 0 0.5rem;
    font-size: var(--text-xs);
  }
}

/* ----------------------------------------------------------------
   24b. POST NAVIGATION (prev / next)
   ---------------------------------------------------------------- */
.post-nav {
  display: grid;
  grid-template-columns: 1fr 1fr;
  margin-top: var(--space-16);
  padding-top: var(--space-6);
  border-top: 1px solid var(--color-border);
}

.post-nav-cell {
  padding: var(--space-5) 0;
}

.post-nav-cell + .post-nav-cell {
  border-left: 1px solid var(--color-border-light);
  padding-left: var(--space-8);
}

.post-nav-older { padding-right: var(--space-8); }
.post-nav-newer { text-align: right; }

.post-nav-link,
.post-nav-empty {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.post-nav-link {
  color: var(--color-text);
  text-decoration: none;
  transition: color var(--transition-base);
}

.post-nav-label {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-family: var(--font-sans);
  font-size: var(--text-xs);
  font-weight: var(--weight-semibold);
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--color-secondary-dark);
}

.post-nav-newer .post-nav-label { justify-content: flex-end; }

.post-nav-arrow {
  display: inline-block;
  font-size: var(--text-sm);
  letter-spacing: 0;
  color: var(--color-secondary-dark);
  transition: transform var(--transition-base);
}

.post-nav-title {
  font-size: var(--text-lg);
  font-weight: var(--weight-medium);
  line-height: var(--leading-snug);
  color: var(--color-primary);
  display: -webkit-box;
  -webkit-line-clamp: 2;
  line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
  transition: color var(--transition-base);
}

.post-nav-date {
  font-size: var(--text-xs);
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.05em;
  color: var(--color-text-muted);
}

a.post-nav-link:hover .post-nav-title {
  color: var(--color-primary-dark);
  text-decoration: underline;
  text-decoration-color: var(--color-secondary);
  text-decoration-thickness: 2px;
  text-underline-offset: 4px;
}

a.post-nav-link:hover .post-nav-arrow {
  color: var(--color-secondary);
}

.post-nav-older a.post-nav-link:hover .post-nav-arrow { transform: translateX(-3px); }
.post-nav-newer a.post-nav-link:hover .post-nav-arrow { transform: translateX(3px); }

.post-nav-empty .post-nav-label { opacity: 0.55; }

.post-nav-placeholder {
  font-size: var(--text-sm);
  font-style: italic;
  color: var(--color-text-muted);
}

@media (max-width: 640px) {
  .post-nav {
    grid-template-columns: 1fr;
  }
  .post-nav-cell + .post-nav-cell {
    border-left: none;
    border-top: 1px solid var(--color-border-light);
    padding-left: 0;
    padding-top: var(--space-5);
  }
  .post-nav-older { padding-right: 0; }
  .post-nav-newer { text-align: left; }
  .post-nav-newer .post-nav-label { justify-content: flex-start; }
}

/* ----------------------------------------------------------------
   25. PRINT STYLES
   ---------------------------------------------------------------- */
@media print {
  .navbar, .footer, .hero-scroll-indicator, .btn { display: none; }
  .page-header { padding-top: var(--space-8); }
  body { font-size: 12pt; }
}