/* ========================================
   IPL Lab Brand Design System
   Portfolio - JUNG Hyeji
   ======================================== */

/* CSS Variables - IPL Lab Brand */
:root {
  /* Colors */
  --ipl-main: #00BCD4;
  --ipl-bg: #020403;
  --ipl-bg-elevated: #0a0f0d;
  --ipl-light: #4DD0E1;
  --ipl-deep: #00838F;
  --ipl-text-primary: #E8EAF6;
  --ipl-text-secondary: #9E9E9E;
  --ipl-text-muted: #4a4a4a;

  /* Super Accent */
  --ipl-super-orange: #FF6B35;
  --ipl-super-yellow: #FFD93D;
  --ipl-super-gradient: linear-gradient(135deg, #FF6B35, #FFD93D);

  /* Typography - 고딕체 */
  --ipl-font-kr: 'Pretendard', 'Noto Sans KR', -apple-system, sans-serif;
  --ipl-font-en-heading: 'Pretendard', 'Noto Sans KR', sans-serif;
  --ipl-font-en-script: 'Pretendard', 'Noto Sans KR', sans-serif;

  /* Glow Effects - 절반으로 감소 */
  --ipl-glow-sm: 0 0 2px var(--ipl-main), 0 0 5px var(--ipl-main);
  --ipl-glow-md: 0 0 5px var(--ipl-main), 0 0 10px var(--ipl-main), 0 0 15px var(--ipl-light);
  --ipl-glow-lg: 0 0 5px var(--ipl-main), 0 0 10px var(--ipl-main), 0 0 20px var(--ipl-light), 0 0 30px var(--ipl-deep);

  /* Spacing */
  --space-xs: 0.5rem;
  --space-sm: 1rem;
  --space-md: 2rem;
  --space-lg: 4rem;
  --space-xl: 8rem;
}

/* ========================================
   Base Styles
   ======================================== */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

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

body {
  font-family: var(--ipl-font-kr);
  background-color: var(--ipl-bg);
  color: var(--ipl-text-primary);
  line-height: 1.7;
  overflow-x: hidden;
}

/* Selection */
::selection {
  background: var(--ipl-main);
  color: var(--ipl-bg);
}

/* Links */
a {
  color: var(--ipl-main);
  text-decoration: none;
  transition: all 0.3s ease;
}

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

/* Container */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-md);
}

/* ========================================
   Typography Classes
   ======================================== */
.neon-text {
  color: var(--ipl-main);
  text-shadow: var(--ipl-glow-md);
}

.neon-text-strong {
  color: var(--ipl-light);
  text-shadow: var(--ipl-glow-lg);
}

.script-text {
  font-family: var(--ipl-font-en-script);
  color: var(--ipl-text-primary);
  text-shadow: 0 0 8px rgba(0, 188, 212, 0.6);
  letter-spacing: normal;
}

.highlight {
  color: var(--ipl-main);
  font-weight: 500;
}

/* ========================================
   Navigation
   ======================================== */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  padding: var(--space-sm) 0;
  background: rgba(2, 4, 3, 0.9);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid rgba(0, 188, 212, 0.1);
}

.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-md);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.nav-logo {
  font-family: var(--ipl-font-en-heading);
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--ipl-main);
  text-shadow: var(--ipl-glow-sm);
}

.nav-links {
  display: flex;
  list-style: none;
  gap: var(--space-md);
}

.nav-links a {
  font-size: 0.9rem;
  color: var(--ipl-text-secondary);
  text-transform: uppercase;
  letter-spacing: normal;
  padding: 0.5rem 0;
  position: relative;
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 1px;
  background: var(--ipl-main);
  box-shadow: var(--ipl-glow-sm);
  transition: width 0.3s ease;
}

.nav-links a:hover {
  color: var(--ipl-main);
}

.nav-links a:hover::after {
  width: 100%;
}

/* Language Toggle */
.lang-toggle {
  display: flex;
  align-items: center;
  gap: 0.25rem;
  background: transparent;
  border: 1px solid rgba(0, 188, 212, 0.3);
  border-radius: 20px;
  padding: 0.4rem 0.8rem;
  cursor: pointer;
  font-size: 0.75rem;
  font-weight: 500;
  margin-right: var(--space-sm);
  transition: all 0.3s ease;
}

.lang-toggle:hover {
  border-color: var(--ipl-main);
}

.lang-toggle .lang-ko,
.lang-toggle .lang-en {
  color: var(--ipl-text-muted);
  transition: color 0.3s ease;
}

.lang-toggle .lang-ko.active,
.lang-toggle .lang-en.active {
  color: var(--ipl-main);
  text-shadow: var(--ipl-glow-sm);
}

.lang-toggle .lang-divider {
  color: var(--ipl-text-muted);
}

/* Language Visibility */
.lang-ko .text-en {
  display: none !important;
}

.lang-en .text-ko {
  display: none !important;
}

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 5px;
}

.nav-toggle span {
  width: 25px;
  height: 2px;
  background: var(--ipl-main);
  transition: all 0.3s ease;
}

/* ========================================
   Hero Section
   ======================================== */
.hero {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  position: relative;
  padding: var(--space-xl) var(--space-md);
  overflow: hidden;
}

.hero-bg {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse at 20% 50%, rgba(0, 188, 212, 0.08) 0%, transparent 50%),
    radial-gradient(ellipse at 80% 50%, rgba(0, 131, 143, 0.06) 0%, transparent 50%),
    radial-gradient(ellipse at 50% 100%, rgba(0, 188, 212, 0.05) 0%, transparent 40%);
  animation: bgPulse 8s ease-in-out infinite;
}

@keyframes bgPulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.7; }
}

.hero-content {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-lg);
  z-index: 1;
  text-align: center;
}

/* Profile Photo */
.hero-photo {
  position: relative;
}

.profile-img {
  width: 360px;
  height: 360px;
  border-radius: 50%;
  object-fit: cover;
  object-position: center 35%;
  border: 4px solid var(--ipl-main);
  box-shadow: var(--ipl-glow-sm);
}

.photo-placeholder {
  width: 150px;
  height: 150px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--ipl-bg-elevated) 0%, var(--ipl-bg) 100%);
  border: 3px solid var(--ipl-main);
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  overflow: hidden;
}

.photo-initial {
  font-family: var(--ipl-font-en-heading);
  font-size: 4rem;
  font-weight: 700;
  color: var(--ipl-main);
  text-shadow: var(--ipl-glow-md);
}

.photo-glow {
  position: absolute;
  inset: -20px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(0, 188, 212, 0.3) 0%, transparent 70%);
  animation: glowPulse 3s ease-in-out infinite;
  pointer-events: none;
}

@keyframes glowPulse {
  0%, 100% { transform: scale(1); opacity: 0.5; }
  50% { transform: scale(1.1); opacity: 0.8; }
}

/* Hero Text */
.hero-subtitle {
  font-size: 1.5rem;
  margin-bottom: var(--space-xs);
}

.hero-name {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.name-main {
  font-size: 3.5rem;
  font-weight: 700;
  color: var(--ipl-text-primary);
  letter-spacing: normal;
}

.name-sub {
  font-size: 1.1rem;
  font-weight: 400;
  color: var(--ipl-text-secondary);
  letter-spacing: normal;
}

.hero-title {
  font-size: 1.1rem;
  color: var(--ipl-light);
  margin-top: 0.5rem;
}

.hero-tagline {
  margin-top: var(--space-xs);
  font-size: 0.95rem;
  color: var(--ipl-text-secondary);
  letter-spacing: normal;
}

/* Hero Contact List - Full Button Style */
.hero-contact-list {
  display: flex;
  flex-direction: column;
  gap: 0.625rem;
  margin-top: var(--space-lg);
  width: 100%;
  max-width: 480px;
  padding: 0 var(--space-sm);
}

.contact-card {
  display: flex;
  align-items: center;
  gap: 0.625rem;
  padding: 0.625rem 1rem;
  background: var(--ipl-bg-elevated);
  border: 1px solid rgba(0, 188, 212, 0.2);
  border-radius: 12px;
  color: var(--ipl-text-primary);
  transition: all 0.3s ease;
}

.contact-card:hover {
  border-color: var(--ipl-main);
  background: rgba(0, 188, 212, 0.08);
  transform: translateX(4px);
}

.contact-card-icon {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: rgba(0, 188, 212, 0.15);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  transition: all 0.3s ease;
}

.contact-card:hover .contact-card-icon {
  background: rgba(0, 188, 212, 0.25);
}

.contact-card-icon svg {
  color: var(--ipl-main);
}

.contact-card-icon img {
  width: 22px;
  height: 22px;
}

/* Brunch 아이콘 스타일 - 기본 사이안 색상 사용 */

/* Instagram 아이콘 스타일 */
.contact-card-icon-instagram {
  background: linear-gradient(135deg, rgba(131, 58, 180, 0.15), rgba(253, 29, 29, 0.15), rgba(252, 176, 69, 0.15));
}

.contact-card:hover .contact-card-icon-instagram {
  background: linear-gradient(135deg, rgba(131, 58, 180, 0.25), rgba(253, 29, 29, 0.25), rgba(252, 176, 69, 0.25));
}

.contact-card-text {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 0.15rem;
}

.contact-card-label {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--ipl-text-primary);
}

.contact-card-value {
  font-size: 0.8rem;
  color: var(--ipl-text-secondary);
}

.contact-card-arrow {
  font-size: 1.5rem;
  color: var(--ipl-text-muted);
  transition: all 0.3s ease;
}

.contact-card:hover .contact-card-arrow {
  color: var(--ipl-main);
  transform: translateX(4px);
}

/* Scroll Indicator */
.scroll-indicator {
  position: absolute;
  bottom: var(--space-md);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
  color: var(--ipl-text-secondary);
  font-size: 0.8rem;
  letter-spacing: normal;
  text-transform: uppercase;
  animation: bounce 2s infinite;
}

.scroll-arrow {
  width: 1px;
  height: 40px;
  background: linear-gradient(to bottom, var(--ipl-main), transparent);
}

@keyframes bounce {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(10px); }
}

/* ========================================
   Section Base Styles
   ======================================== */
.section {
  padding: var(--space-xl) 0;
  position: relative;
}

.section-header {
  display: flex;
  align-items: baseline;
  gap: var(--space-sm);
  margin-bottom: var(--space-lg);
}

.section-number {
  font-family: var(--ipl-font-en-heading);
  font-size: 1rem;
  color: var(--ipl-text-muted);
  letter-spacing: normal;
}

.section-title {
  font-family: var(--ipl-font-en-heading);
  font-size: 2.5rem;
  font-weight: 600;
  letter-spacing: normal;
}

/* ========================================
   Vision Section
   ======================================== */
.vision-content {
  max-width: 900px;
}

.vision-quote {
  border-left: 2px solid var(--ipl-main);
  padding-left: var(--space-md);
  margin-bottom: var(--space-lg);
}

.vision-text-kr {
  font-size: 1.3rem;
  line-height: 2;
  margin-bottom: var(--space-md);
}

.vision-text-en {
  font-family: var(--ipl-font-en-heading);
  font-size: 1rem;
  color: var(--ipl-text-secondary);
  line-height: 1.8;
  font-style: italic;
}

/* Three Brains */
.three-brains {
  margin-top: var(--space-lg);
}

.brains-title {
  font-size: 2rem;
  margin-bottom: var(--space-md);
  text-align: center;
}

.brains-diagram {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  flex-wrap: wrap;
}

.brain-card {
  background: var(--ipl-bg-elevated);
  border: 1px solid rgba(0, 188, 212, 0.2);
  border-radius: 12px;
  padding: var(--space-md);
  text-align: center;
  min-width: 200px;
  transition: all 0.3s ease;
}

.brain-card:hover {
  border-color: var(--ipl-main);
  box-shadow: var(--ipl-glow-sm);
  transform: translateY(-5px);
}

.brain-icon {
  font-size: 2.5rem;
  margin-bottom: var(--space-xs);
}

.brain-card h4 {
  font-size: 1.1rem;
  color: var(--ipl-text-primary);
  margin-bottom: 0.25rem;
}

.brain-en {
  font-family: var(--ipl-font-en-heading);
  font-size: 0.9rem;
  color: var(--ipl-main);
  margin-bottom: var(--space-xs);
}

.brain-function {
  font-size: 0.85rem;
  color: var(--ipl-text-secondary);
  margin-bottom: var(--space-xs);
}

.brain-keyword {
  display: inline-block;
  font-size: 0.75rem;
  color: var(--ipl-bg);
  background: var(--ipl-super-gradient);
  padding: 0.25rem 0.75rem;
  border-radius: 20px;
  font-weight: 600;
  letter-spacing: normal;
}

.brain-connector {
  font-size: 1.5rem;
  color: var(--ipl-main);
  text-shadow: var(--ipl-glow-sm);
}

/* Brains Diagram Image */
.brains-diagram-img {
  display: flex;
  justify-content: center;
  align-items: center;
  margin-top: var(--space-md);
}

.brains-img {
  max-width: 100%;
  width: 700px;
  height: auto;
  border-radius: 12px;
  box-shadow: 0 4px 20px rgba(0, 188, 212, 0.1);
}

/* ========================================
   About Section
   ======================================== */
.about-intro {
  max-width: 800px;
  margin-bottom: var(--space-lg);
}

.intro-kr {
  font-size: 1.2rem;
  line-height: 2;
  margin-bottom: var(--space-sm);
}

.intro-en {
  font-family: var(--ipl-font-en-heading);
  font-size: 0.95rem;
  color: var(--ipl-text-secondary);
  line-height: 1.8;
}

/* Profile Grid */
.profile-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: var(--space-md);
  margin-bottom: var(--space-lg);
}

.profile-card {
  background: var(--ipl-bg-elevated);
  border: 1px solid rgba(0, 188, 212, 0.15);
  border-radius: 12px;
  padding: var(--space-md);
  transition: all 0.3s ease;
}

.profile-card:hover {
  border-color: var(--ipl-main);
  box-shadow: inset 0 0 20px rgba(0, 188, 212, 0.1);
}

.card-icon {
  font-size: 1.5rem;
  margin-bottom: var(--space-xs);
}

.profile-card h4 {
  font-size: 1rem;
  color: var(--ipl-text-primary);
  margin-bottom: 0.25rem;
}

.profile-card p {
  font-size: 0.9rem;
  color: var(--ipl-main);
}

/* 링크 카드 스타일 */
a.profile-card-link {
  text-decoration: none;
  display: block;
}

a.profile-card-link:hover {
  transform: translateY(-2px);
  box-shadow: var(--ipl-glow-sm);
}

.card-en {
  display: block;
  font-size: 0.8rem;
  color: var(--ipl-text-secondary);
  margin-top: 0.5rem;
}

/* Subsections */
.about-subsection {
  margin-bottom: var(--space-lg);
  padding-top: var(--space-md);
  border-top: 1px solid rgba(0, 188, 212, 0.1);
}

.subsection-title {
  font-family: var(--ipl-font-en-heading);
  font-size: 1.3rem;
  color: var(--ipl-main);
  margin-bottom: var(--space-md);
  letter-spacing: normal;
}

/* Timeline */
.timeline {
  position: relative;
  padding-left: var(--space-lg);
}

.timeline::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 1px;
  background: linear-gradient(to bottom, var(--ipl-main), transparent);
}

.timeline-item {
  position: relative;
  margin-bottom: var(--space-md);
}

.timeline-badge {
  position: absolute;
  left: calc(-1 * var(--space-lg) - 20px);
  width: 40px;
  height: 40px;
  background: var(--ipl-bg);
  border: 2px solid var(--ipl-main);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.7rem;
  font-weight: 700;
  color: var(--ipl-main);
}

.timeline-content h4 {
  font-size: 1.1rem;
  color: var(--ipl-text-primary);
  margin-bottom: 0.25rem;
}

.timeline-content p {
  font-size: 0.95rem;
  color: var(--ipl-text-secondary);
}

.timeline-en {
  display: block;
  font-size: 0.85rem;
  color: var(--ipl-text-muted);
  margin-top: 0.25rem;
}

.timeline-date {
  display: inline-block;
  font-size: 0.8rem;
  color: var(--ipl-main);
  margin-top: 0.5rem;
}

/* Experience List */
.experience-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}

.experience-item {
  padding: var(--space-md);
  background: var(--ipl-bg-elevated);
  border-radius: 8px;
  border-left: 3px solid var(--ipl-main);
}

.exp-header {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  margin-bottom: 0.5rem;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.exp-header h4 {
  font-size: 1.1rem;
  color: var(--ipl-text-primary);
}

.exp-date {
  font-size: 0.85rem;
  color: var(--ipl-main);
}

.exp-role {
  font-size: 0.95rem;
  color: var(--ipl-light);
  margin-bottom: 0.25rem;
}

.exp-desc {
  font-size: 0.9rem;
  color: var(--ipl-text-secondary);
}

/* Studies List */
.studies-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.study-item {
  display: flex;
  gap: var(--space-sm);
  padding: var(--space-sm);
  border-radius: 6px;
  transition: background 0.3s ease;
}

.study-item:hover {
  background: var(--ipl-bg-elevated);
}

.study-year {
  min-width: 50px;
  font-size: 0.85rem;
  color: var(--ipl-main);
  font-weight: 500;
}

.study-item p {
  font-size: 0.95rem;
  color: var(--ipl-text-secondary);
}

.btn-more {
  margin-top: var(--space-sm);
  padding: 0.5rem 1.5rem;
  background: transparent;
  border: 1px solid var(--ipl-text-muted);
  color: var(--ipl-text-secondary);
  border-radius: 20px;
  cursor: pointer;
  font-size: 0.85rem;
  transition: all 0.3s ease;
}

.btn-more:hover {
  border-color: var(--ipl-main);
  color: var(--ipl-main);
}

/* Certifications */
.cert-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--space-sm);
}

.cert-item {
  padding: var(--space-sm);
  border: 1px solid rgba(0, 188, 212, 0.1);
  border-radius: 8px;
}

.cert-label {
  display: inline-block;
  font-size: 0.75rem;
  color: var(--ipl-main);
  background: rgba(0, 188, 212, 0.1);
  padding: 0.2rem 0.6rem;
  border-radius: 4px;
  margin-bottom: 0.5rem;
}

.cert-item p {
  font-size: 0.9rem;
  color: var(--ipl-text-secondary);
}

/* ========================================
   Projects Section
   ======================================== */
.project-tabs {
  display: flex;
  gap: var(--space-xs);
  margin-bottom: var(--space-lg);
  flex-wrap: wrap;
}

.tab-btn {
  padding: 0.75rem 1.5rem;
  background: transparent;
  border: 1px solid rgba(0, 188, 212, 0.3);
  color: var(--ipl-text-secondary);
  border-radius: 25px;
  cursor: pointer;
  font-family: var(--ipl-font-en-heading);
  font-size: 0.9rem;
  letter-spacing: normal;
  transition: all 0.3s ease;
}

.tab-btn:hover {
  border-color: var(--ipl-main);
  color: var(--ipl-main);
}

.tab-btn.active {
  background: var(--ipl-main);
  border-color: var(--ipl-main);
  color: var(--ipl-bg);
  box-shadow: var(--ipl-glow-sm);
}

/* Project Panels */
.project-section {
  display: block;
  margin-bottom: var(--space-lg);
  padding-top: var(--space-md);
  border-top: 1px solid rgba(0, 188, 212, 0.2);
}

.project-section:first-of-type {
  border-top: none;
  padding-top: 0;
}

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

.panel-title {
  font-size: 1.8rem;
  margin-bottom: var(--space-md);
}

/* Project Timeline */
.project-timeline {
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}

.project-year {
  display: grid;
  grid-template-columns: 100px 1fr;
  gap: var(--space-md);
  align-items: start;
}

.year-label {
  font-family: var(--ipl-font-en-heading);
  font-size: 1.2rem;
  color: var(--ipl-main);
  font-weight: 600;
  text-shadow: var(--ipl-glow-sm);
}

.project-items {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.project-item {
  padding: var(--space-sm) var(--space-md);
  background: var(--ipl-bg-elevated);
  border-radius: 8px;
  border-left: 2px solid var(--ipl-deep);
  transition: all 0.3s ease;
}

.project-item:hover {
  border-left-color: var(--ipl-main);
  box-shadow: inset 0 0 15px rgba(0, 188, 212, 0.05);
}

.project-item h4 {
  font-size: 1rem;
  color: var(--ipl-text-primary);
  margin-bottom: 0.25rem;
}

.project-item p {
  font-size: 0.9rem;
  color: var(--ipl-text-secondary);
}

/* Lecture Table */
.lecture-table {
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
}

.lecture-item {
  display: grid;
  grid-template-columns: 80px 200px 1fr;
  gap: var(--space-sm);
  padding: var(--space-sm);
  border-radius: 6px;
  transition: background 0.3s ease;
  align-items: start;
}

.lecture-item:hover {
  background: var(--ipl-bg-elevated);
}

.lecture-date {
  font-size: 0.85rem;
  color: var(--ipl-main);
}

.lecture-org {
  font-size: 0.9rem;
  color: var(--ipl-text-primary);
}

.lecture-title {
  font-size: 0.9rem;
  color: var(--ipl-text-secondary);
}

/* ========================================
   Contact Section
   ======================================== */
.contact {
  text-align: center;
  background:
    radial-gradient(ellipse at 50% 0%, rgba(0, 188, 212, 0.1) 0%, transparent 50%);
}

.contact-content {
  max-width: 700px;
  margin: 0 auto;
}

.contact-title {
  font-size: 3rem;
  margin-bottom: var(--space-md);
}

.contact-text {
  font-size: 1.1rem;
  line-height: 1.9;
  margin-bottom: var(--space-sm);
}

.contact-text-en {
  font-family: var(--ipl-font-en-heading);
  font-size: 0.95rem;
  color: var(--ipl-text-secondary);
  margin-bottom: var(--space-lg);
}

/* Contact Links */
.contact-links {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
  align-items: center;
}

.contact-link {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: 1rem 2rem;
  min-width: 300px;
  justify-content: center;
}

.neon-btn {
  background: transparent;
  border: 2px solid var(--ipl-main);
  color: var(--ipl-main);
  box-shadow: var(--ipl-glow-sm);
  border-radius: 50px;
  transition: all 0.3s ease;
}

.neon-btn:hover {
  background: var(--ipl-main);
  color: var(--ipl-bg);
  text-shadow: none;
  box-shadow: var(--ipl-glow-lg);
}

.link-icon {
  font-size: 1.2rem;
}

.link-text {
  font-size: 1rem;
}

/* ========================================
   Footer
   ======================================== */
.footer {
  padding: var(--space-md) 0;
  text-align: center;
  border-top: 1px solid rgba(0, 188, 212, 0.1);
}

.back-to-top {
  display: inline-block;
  font-size: 0.9rem;
  color: var(--ipl-text-secondary);
  margin-bottom: var(--space-sm);
  transition: color 0.3s ease;
}

.back-to-top:hover {
  color: var(--ipl-main);
}

.copyright {
  font-size: 0.85rem;
  color: var(--ipl-text-muted);
}

/* ========================================
   Responsive Design
   ======================================== */

/* Tablet */
@media (max-width: 1024px) {
  :root {
    font-size: 15px;
  }

  /* Contact Cards - 태블릿 */
  .hero-contact-list {
    max-width: 440px;
  }

  .contact-card-icon {
    width: 44px;
    height: 44px;
  }

  .lecture-item {
    grid-template-columns: 80px 1fr;
  }

  .lecture-title {
    grid-column: 1 / -1;
    margin-top: 0.25rem;
  }
}

/* Mobile */
@media (max-width: 768px) {
  :root {
    font-size: 14px;
  }

  /* Navigation */
  .nav-links {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: rgba(2, 4, 3, 0.98);
    flex-direction: column;
    padding: var(--space-md);
    gap: var(--space-sm);
    border-bottom: 1px solid rgba(0, 188, 212, 0.2);
  }

  .nav-links.active {
    display: flex;
  }

  .nav-toggle {
    display: flex;
  }

  .nav-toggle.active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
  }

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

  .nav-toggle.active span:nth-child(3) {
    transform: rotate(-45deg) translate(5px, -5px);
  }

  /* Hero - 모바일 명함 스타일 */
  .hero {
    min-height: 100vh;
    padding: var(--space-lg) var(--space-sm);
  }

  .hero-content {
    gap: var(--space-md);
  }

  .profile-img {
    width: 120px;
    height: 120px;
  }

  .name-main {
    font-size: 2.2rem;
  }

  .name-sub {
    font-size: 0.95rem;
  }

  .hero-title {
    font-size: 0.9rem;
  }

  .hero-tagline {
    font-size: 0.85rem;
  }

  /* Contact Cards - 모바일 (푸터 스타일) */
  .hero-contact-list {
    position: relative;
    width: calc(100vw - 2rem);
    left: 50%;
    transform: translateX(-50%);
    max-width: none;
    margin-top: 1.25rem;
    padding: 0;
    gap: 0.75rem;
  }

  .contact-card {
    padding: 0.875rem 1.25rem;
    gap: 0.75rem;
    border-radius: 50px;
    border: 2px solid var(--ipl-main);
    box-shadow: var(--ipl-glow-sm);
    background: transparent;
  }

  .contact-card:hover {
    box-shadow: var(--ipl-glow-md);
  }

  .contact-card-icon {
    width: 40px;
    height: 40px;
  }

  .contact-card-icon svg {
    width: 18px;
    height: 18px;
  }

  .contact-card-icon img {
    width: 18px;
    height: 18px;
  }

  .contact-card-label {
    font-size: 0.8rem;
  }

  .contact-card-value {
    font-size: 0.75rem;
  }

  .contact-card-arrow {
    font-size: 1.2rem;
  }

  /* 모바일에서 스크롤 인디케이터 숨김 */
  .scroll-indicator {
    display: none;
  }

  .hero-buttons {
    grid-template-columns: repeat(2, 1fr);
    gap: 0.5rem;
    max-width: 280px;
  }

  .hero-btn {
    padding: 0.8rem 0.4rem;
    font-size: 0.7rem;
  }

  .hero-btn .btn-icon {
    font-size: 1.3rem;
  }

  /* Three Brains */
  .brains-diagram {
    flex-direction: column;
  }

  .brain-connector {
    transform: rotate(90deg);
  }

  /* Project Year */
  .project-year {
    grid-template-columns: 1fr;
  }

  .year-label {
    margin-bottom: 0.5rem;
  }

  /* Lecture */
  .lecture-item {
    grid-template-columns: 1fr;
    gap: 0.25rem;
  }

  .lecture-org {
    color: var(--ipl-light);
  }

  /* Contact */
  .contact-title {
    font-size: 2rem;
  }

  .contact-link {
    min-width: 100%;
  }
}

/* Small Mobile */
@media (max-width: 480px) {
  .section {
    padding: var(--space-lg) 0;
  }

  .section-title {
    font-size: 2rem;
  }

  .name-main {
    font-size: 1.8rem;
  }

  .name-sub {
    font-size: 0.85rem;
  }

  .photo-placeholder {
    width: 140px;
    height: 140px;
  }

  .photo-initial {
    font-size: 3rem;
  }

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

  .timeline {
    padding-left: var(--space-md);
  }

  .timeline-badge {
    left: calc(-1 * var(--space-md) - 15px);
    width: 30px;
    height: 30px;
    font-size: 0.6rem;
  }

  /* Contact Cards - 작은 모바일 (풀 와이드 유지) */
  .contact-card {
    padding: 0.875rem 1rem;
  }

  .contact-card-icon {
    width: 36px;
    height: 36px;
  }

  .contact-card-icon svg {
    width: 16px;
    height: 16px;
  }

  .contact-card-icon img {
    width: 16px;
    height: 16px;
  }

  .contact-card-label {
    font-size: 0.75rem;
  }

  .contact-card-value {
    font-size: 0.7rem;
  }

  .contact-card-arrow {
    font-size: 1rem;
  }
}

/* ========================================
   Animations
   ======================================== */

/* Fade In Up */
.fade-in-up {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-in-up.visible {
  opacity: 1;
  transform: translateY(0);
}

/* Stagger Children */
.stagger-children > * {
  opacity: 0;
  transform: translateY(20px);
}

.stagger-children.visible > * {
  opacity: 1;
  transform: translateY(0);
  transition: opacity 0.5s ease, transform 0.5s ease;
}

.stagger-children.visible > *:nth-child(1) { transition-delay: 0.1s; }
.stagger-children.visible > *:nth-child(2) { transition-delay: 0.2s; }
.stagger-children.visible > *:nth-child(3) { transition-delay: 0.3s; }
.stagger-children.visible > *:nth-child(4) { transition-delay: 0.4s; }
.stagger-children.visible > *:nth-child(5) { transition-delay: 0.5s; }
.stagger-children.visible > *:nth-child(6) { transition-delay: 0.6s; }

/* Neon Pulse */
@keyframes neonPulse {
  0%, 100% {
    text-shadow: var(--ipl-glow-md);
  }
  50% {
    text-shadow: var(--ipl-glow-lg);
  }
}

.neon-pulse {
  animation: neonPulse 2s ease-in-out infinite;
}