/* ==========================================================================
   신건영 (Geonyeong Shin) Portfolio Design System & Stylesheet
   ========================================================================== */

/* Design Tokens & Theme Variables */
:root {
  /* Dark Theme (Default) */
  --bg-primary: #0A0D14;
  --bg-secondary: #101522;
  --bg-tertiary: #161D2E;
  --bg-card: rgba(22, 29, 46, 0.75);
  --bg-card-hover: rgba(28, 37, 58, 0.85);
  --bg-glass: rgba(16, 21, 34, 0.8);
  
  --text-primary: #F3F4F6;
  --text-secondary: #9CA3AF;
  --text-muted: #6B7280;
  
  --accent-primary: #3B82F6;
  --accent-primary-hover: #2563EB;
  --accent-secondary: #06B6D4;
  --accent-purple: #8B5CF6;
  --accent-soft: rgba(59, 130, 246, 0.15);
  --accent-border: rgba(59, 130, 246, 0.3);
  
  --border-color: rgba(255, 255, 255, 0.08);
  --border-color-hover: rgba(255, 255, 255, 0.16);
  
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 16px 36px rgba(0, 0, 0, 0.5);
  --shadow-glow: 0 0 30px rgba(59, 130, 246, 0.25);
  
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --radius-full: 9999px;
  
  --font-sans: 'Plus Jakarta Sans', 'Noto Sans KR', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-heading: 'Space Grotesk', 'Plus Jakarta Sans', 'Noto Sans KR', sans-serif;
  --font-mono: 'Fira Code', monospace;
  
  --max-width: 1160px;
  --transition-fast: 0.2s ease;
  --transition-normal: 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

/* Light Theme Variables */
[data-theme="light"] {
  --bg-primary: #F8FAFC;
  --bg-secondary: #FFFFFF;
  --bg-tertiary: #F1F5F9;
  --bg-card: rgba(255, 255, 255, 0.85);
  --bg-card-hover: #FFFFFF;
  --bg-glass: rgba(255, 255, 255, 0.85);
  
  --text-primary: #0F172A;
  --text-secondary: #475569;
  --text-muted: #94A3B8;
  
  --accent-primary: #2563EB;
  --accent-primary-hover: #1D4ED8;
  --accent-secondary: #0891B2;
  --accent-purple: #7C3AED;
  --accent-soft: rgba(37, 99, 235, 0.1);
  --accent-border: rgba(37, 99, 235, 0.25);
  
  --border-color: rgba(15, 23, 42, 0.08);
  --border-color-hover: rgba(15, 23, 42, 0.16);
  
  --shadow-sm: 0 2px 6px rgba(15, 23, 42, 0.05);
  --shadow-md: 0 8px 24px rgba(15, 23, 42, 0.08);
  --shadow-lg: 0 16px 36px rgba(15, 23, 42, 0.12);
  --shadow-glow: 0 0 30px rgba(37, 99, 235, 0.15);
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
  scroll-padding-top: 80px;
}

body {
  background-color: var(--bg-primary);
  color: var(--text-primary);
  font-family: var(--font-sans);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
  transition: background-color var(--transition-normal), color var(--transition-normal);
}

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

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

ul, ol {
  list-style: none;
}

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

/* Utility Containers */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

.section {
  padding: 6.5rem 0;
  position: relative;
}

.section-alt {
  background-color: var(--bg-secondary);
}

.section-header {
  margin-bottom: 3.5rem;
}

.section-badge {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--accent-primary);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  margin-bottom: 0.75rem;
  padding: 0.3rem 0.75rem;
  border-radius: var(--radius-full);
  background: var(--accent-soft);
  border: 1px solid var(--accent-border);
}

.section-title {
  font-family: var(--font-heading);
  font-size: clamp(1.8rem, 3.5vw, 2.5rem);
  font-weight: 700;
  line-height: 1.25;
  color: var(--text-primary);
  margin-bottom: 0.75rem;
}

.section-desc {
  font-size: 1.05rem;
  color: var(--text-secondary);
  max-width: 680px;
}

.text-gradient {
  background: linear-gradient(135deg, #60A5FA 0%, #38BDF8 50%, #A78BFA 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

[data-theme="light"] .text-gradient {
  background: linear-gradient(135deg, #2563EB 0%, #0284C7 50%, #7C3AED 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

/* ==========================================================================
   Navigation Bar
   ========================================================================== */
.nav-wrap {
  position: sticky;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: var(--bg-glass);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border-color);
  transition: all var(--transition-fast);
}

.nav-container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0.85rem 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: 0.65rem;
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 1.15rem;
  color: var(--text-primary);
}

.brand-badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 34px;
  height: 34px;
  border-radius: 10px;
  background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
  color: #FFFFFF;
  font-size: 0.9rem;
  font-weight: 800;
  box-shadow: 0 2px 10px rgba(59, 130, 246, 0.4);
}

.nav-right {
  display: flex;
  align-items: center;
  gap: 2rem;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 1.5rem;
}

.nav-item {
  font-size: 0.92rem;
  font-weight: 500;
  color: var(--text-secondary);
  padding: 0.4rem 0.6rem;
  border-radius: var(--radius-sm);
  transition: color var(--transition-fast), background-color var(--transition-fast);
}

.nav-item:hover, .nav-item.active {
  color: var(--accent-primary);
  background: var(--accent-soft);
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

/* Theme Toggle Button */
.theme-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 38px;
  height: 38px;
  border-radius: var(--radius-full);
  background: var(--bg-tertiary);
  color: var(--text-primary);
  border: 1px solid var(--border-color);
  transition: all var(--transition-fast);
}

.theme-toggle:hover {
  background: var(--accent-soft);
  color: var(--accent-primary);
  border-color: var(--accent-border);
  transform: rotate(15deg);
}

[data-theme="dark"] .sun-icon { display: block; }
[data-theme="dark"] .moon-icon { display: none; }
[data-theme="light"] .sun-icon { display: none; }
[data-theme="light"] .moon-icon { display: block; }

/* Mobile Nav Toggle */
.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 36px;
  height: 36px;
  padding: 6px;
  border-radius: var(--radius-sm);
  background: var(--bg-tertiary);
}

.nav-toggle span {
  display: block;
  width: 100%;
  height: 2px;
  background: var(--text-primary);
  border-radius: 2px;
  transition: transform var(--transition-fast), opacity var(--transition-fast);
}

.nav-toggle.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle.open span:nth-child(2) { opacity: 0; }
.nav-toggle.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ==========================================================================
   Hero Section
   ========================================================================== */
.hero-section {
  position: relative;
  padding: 6rem 0 5rem;
  overflow: hidden;
}

.hero-glow {
  position: absolute;
  border-radius: 50%;
  filter: blur(120px);
  pointer-events: none;
  z-index: 0;
  opacity: 0.5;
}

.hero-glow-1 {
  top: -100px;
  left: 20%;
  width: 450px;
  height: 450px;
  background: radial-gradient(circle, rgba(59, 130, 246, 0.35) 0%, transparent 70%);
}

.hero-glow-2 {
  bottom: 0;
  right: 15%;
  width: 400px;
  height: 400px;
  background: radial-gradient(circle, rgba(139, 92, 246, 0.25) 0%, transparent 70%);
}

.hero-container {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: 1.25fr 0.75fr;
  gap: 3.5rem;
  align-items: center;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.4rem 0.9rem;
  background: var(--accent-soft);
  border: 1px solid var(--accent-border);
  border-radius: var(--radius-full);
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--accent-primary);
  margin-bottom: 1.25rem;
}

.status-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: #10B981;
  box-shadow: 0 0 0 3px rgba(16, 185, 129, 0.3);
  animation: pulse-dot 2s infinite;
}

@keyframes pulse-dot {
  0% { transform: scale(0.95); box-shadow: 0 0 0 0 rgba(16, 185, 129, 0.6); }
  70% { transform: scale(1); box-shadow: 0 0 0 6px rgba(16, 185, 129, 0); }
  100% { transform: scale(0.95); box-shadow: 0 0 0 0 rgba(16, 185, 129, 0); }
}

.hero-title {
  font-family: var(--font-heading);
  font-size: clamp(2.2rem, 4.5vw, 3.2rem);
  font-weight: 800;
  line-height: 1.2;
  margin-bottom: 1.2rem;
  letter-spacing: -0.02em;
}

.hero-subtext {
  font-size: 1.12rem;
  color: var(--text-secondary);
  margin-bottom: 1.5rem;
  line-height: 1.75;
}

.hero-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
  margin-bottom: 1.75rem;
}

.hero-tag {
  font-size: 0.85rem;
  font-weight: 600;
  padding: 0.35rem 0.8rem;
  border-radius: var(--radius-full);
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
}

.hero-meta-list {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  font-size: 0.92rem;
  color: var(--text-secondary);
  margin-bottom: 2rem;
}

.meta-item {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.85rem;
  align-items: center;
}

/* Button Component */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.75rem 1.4rem;
  border-radius: var(--radius-full);
  font-size: 0.92rem;
  font-weight: 600;
  transition: all var(--transition-fast);
}

.btn-primary {
  background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
  color: #FFFFFF;
  box-shadow: 0 4px 14px rgba(59, 130, 246, 0.35);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(59, 130, 246, 0.5);
  color: #FFFFFF;
}

.btn-secondary {
  background: var(--bg-secondary);
  color: var(--text-primary);
  border: 1px solid var(--border-color);
}

.btn-secondary:hover {
  background: var(--bg-tertiary);
  border-color: var(--accent-border);
  color: var(--accent-primary);
  transform: translateY(-2px);
}

.btn-ghost {
  background: transparent;
  color: var(--text-secondary);
  border: 1px solid var(--border-color);
}

.btn-ghost:hover {
  background: var(--accent-soft);
  color: var(--accent-primary);
  border-color: var(--accent-border);
}

.btn-sm {
  padding: 0.45rem 0.9rem;
  font-size: 0.82rem;
  border-radius: var(--radius-full);
}

.btn-outline {
  border: 1px solid var(--border-color);
  background: var(--bg-tertiary);
  color: var(--text-primary);
}

.btn-outline:hover {
  border-color: var(--accent-primary);
  color: var(--accent-primary);
}

.btn-yt:hover {
  color: #EF4444;
  border-color: rgba(239, 68, 68, 0.4);
}

/* Profile Visual Card */
.profile-card-wrapper {
  position: relative;
  max-width: 360px;
  margin: 0 auto;
}

.profile-card {
  position: relative;
  z-index: 2;
  border-radius: var(--radius-lg);
  overflow: hidden;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow-lg);
  transition: transform var(--transition-normal), box-shadow var(--transition-normal);
}

.profile-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-glow), var(--shadow-lg);
  border-color: var(--accent-border);
}

.profile-img-box {
  width: 100%;
  aspect-ratio: 3/4;
  overflow: hidden;
  background: #111;
}

.profile-img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center top;
  transition: transform 0.6s ease;
}

.profile-card:hover .profile-img {
  transform: scale(1.04);
}

.profile-info-overlay {
  padding: 1.25rem 1.5rem;
  background: var(--bg-card);
  backdrop-filter: blur(12px);
  border-top: 1px solid var(--border-color);
}

.profile-name-kr {
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--text-primary);
}

.profile-name-en {
  font-size: 0.9rem;
  color: var(--text-muted);
  font-family: var(--font-heading);
  margin-bottom: 0.4rem;
}

.profile-status {
  display: flex;
  align-items: center;
  gap: 0.45rem;
  font-size: 0.82rem;
  color: var(--accent-primary);
  font-weight: 600;
}

.dot-online {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: #10B981;
}

.profile-card-bg {
  position: absolute;
  inset: -12px;
  border-radius: 26px;
  background: linear-gradient(135deg, var(--accent-primary), var(--accent-purple));
  opacity: 0.3;
  filter: blur(20px);
  z-index: 1;
}

/* ==========================================================================
   About Section
   ========================================================================== */
.about-grid {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: 3.5rem;
  align-items: start;
}

.about-narrative {
  display: flex;
  flex-direction: column;
  gap: 1.15rem;
  font-size: 1.02rem;
  color: var(--text-secondary);
}

.lead-text {
  font-size: 1.15rem;
  font-weight: 500;
  color: var(--text-primary);
  line-height: 1.7;
}

.about-stats {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1rem;
  margin-top: 1.5rem;
}

.stat-card {
  padding: 1.25rem 1.4rem;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  transition: transform var(--transition-fast), border-color var(--transition-fast);
}

.stat-card:hover {
  transform: translateY(-3px);
  border-color: var(--accent-border);
}

.stat-num {
  font-family: var(--font-heading);
  font-size: 2rem;
  font-weight: 800;
  color: var(--accent-primary);
  line-height: 1.1;
  margin-bottom: 0.35rem;
}

.stat-unit {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--accent-secondary);
}

.stat-label {
  font-size: 0.85rem;
  color: var(--text-secondary);
  font-weight: 500;
}

.subsection-title {
  font-family: var(--font-heading);
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 1.2rem;
}

.traits-container {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.trait-card {
  display: flex;
  gap: 1.1rem;
  padding: 1.25rem 1.4rem;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  backdrop-filter: blur(12px);
  transition: transform var(--transition-fast), border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.trait-card:hover {
  transform: translateX(4px);
  border-color: var(--accent-border);
  box-shadow: var(--shadow-sm);
}

.trait-icon {
  font-size: 1.6rem;
  flex-shrink: 0;
}

.trait-content h4 {
  font-size: 0.98rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 0.3rem;
}

.trait-content p {
  font-size: 0.88rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* ==========================================================================
   Research & Skills Section
   ========================================================================== */
.research-pillars {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
  margin-bottom: 3.5rem;
}

.pillar-card {
  padding: 2rem 1.6rem;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  backdrop-filter: blur(12px);
  display: flex;
  flex-direction: column;
  transition: transform var(--transition-normal), border-color var(--transition-normal), box-shadow var(--transition-normal);
}

.pillar-card:hover {
  transform: translateY(-6px);
  border-color: var(--accent-border);
  box-shadow: var(--shadow-md);
}

.pillar-card.highlight-card {
  border-color: var(--accent-border);
  background: linear-gradient(180deg, var(--accent-soft) 0%, var(--bg-card) 100%);
}

.pillar-header {
  display: flex;
  align-items: center;
  gap: 0.85rem;
  margin-bottom: 1rem;
}

.pillar-icon {
  font-size: 1.8rem;
}

.pillar-header h3 {
  font-family: var(--font-heading);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
}

.pillar-desc {
  font-size: 0.92rem;
  color: var(--text-secondary);
  line-height: 1.65;
  margin-bottom: 1.5rem;
  flex-grow: 1;
}

.pillar-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
}

.pillar-tags span {
  font-size: 0.76rem;
  font-weight: 600;
  padding: 0.25rem 0.65rem;
  border-radius: var(--radius-full);
  background: var(--bg-tertiary);
  color: var(--accent-primary);
  border: 1px solid var(--border-color);
}

/* Categorized Skills */
.skills-wrapper {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
}

.skill-category {
  padding: 1.8rem 1.6rem;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
}

.skill-cat-title {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-size: 1rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 1.4rem;
  padding-bottom: 0.75rem;
  border-bottom: 1px solid var(--border-color);
}

.cat-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
}
.cat-ai { background: #3B82F6; box-shadow: 0 0 8px rgba(59,130,246,0.6); }
.cat-data { background: #10B981; box-shadow: 0 0 8px rgba(16,185,129,0.6); }
.cat-dev { background: #8B5CF6; box-shadow: 0 0 8px rgba(139,92,246,0.6); }

.skill-tags {
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
}

.skill-pill {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0.55rem 0.9rem;
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  font-size: 0.88rem;
  font-weight: 500;
  transition: all var(--transition-fast);
}

.skill-pill:hover {
  background: var(--accent-soft);
  border-color: var(--accent-border);
  transform: translateX(3px);
}

.pill-lvl {
  font-style: normal;
  font-size: 0.72rem;
  font-family: var(--font-mono);
  color: var(--text-muted);
}

/* ==========================================================================
   Experience Section (Timeline V2)
   ========================================================================== */
.timeline-v2 {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 2.2rem;
  padding-left: 2rem;
}

.timeline-v2::before {
  content: '';
  position: absolute;
  top: 1.5rem;
  bottom: 1.5rem;
  left: 7px;
  width: 2px;
  background: linear-gradient(180deg, var(--accent-primary) 0%, var(--border-color) 100%);
}

.timeline-card {
  position: relative;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 2rem;
  backdrop-filter: blur(12px);
  transition: transform var(--transition-normal), border-color var(--transition-normal), box-shadow var(--transition-normal);
}

.timeline-card:hover {
  transform: translateX(6px);
  border-color: var(--accent-border);
  box-shadow: var(--shadow-md);
}

.timeline-card.current-role {
  border-color: var(--accent-border);
  background: linear-gradient(135deg, rgba(59, 130, 246, 0.08) 0%, var(--bg-card) 100%);
}

.timeline-marker {
  position: absolute;
  left: -2.42rem;
  top: 2rem;
}

.marker-dot {
  display: block;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--bg-primary);
  border: 3px solid var(--accent-primary);
}

.marker-dot.pulse {
  background: var(--accent-primary);
  box-shadow: 0 0 0 5px var(--accent-soft);
}

.timeline-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 1rem;
  margin-bottom: 1.25rem;
  flex-wrap: wrap;
}

.org-meta {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.org-logo-wrap {
  width: 52px;
  height: 52px;
  border-radius: 12px;
  overflow: hidden;
  background: #FFFFFF;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--border-color);
  flex-shrink: 0;
  padding: 4px;
}

.org-logo-img {
  width: 100%;
  height: 100%;
  object-fit: contain;
}

.pnu-logo-wrap {
  background: linear-gradient(135deg, #003876, #0056B3);
  color: #FFFFFF;
}

.pnu-symbol, .kodit-symbol {
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 0.85rem;
  letter-spacing: 0.05em;
}

.kodit-logo-wrap {
  background: linear-gradient(135deg, #0C3C82, #1868DB);
  color: #FFFFFF;
}

.org-title {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 0.2rem;
}

.org-name {
  font-size: 0.9rem;
  color: var(--text-secondary);
  font-weight: 500;
}

.timeline-period-badge {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--accent-primary);
  padding: 0.35rem 0.85rem;
  background: var(--accent-soft);
  border: 1px solid var(--accent-border);
  border-radius: var(--radius-full);
  white-space: nowrap;
}

.role-desc {
  font-size: 0.95rem;
  color: var(--text-secondary);
  line-height: 1.65;
  margin-bottom: 1.2rem;
}

.role-desc strong {
  color: var(--text-primary);
}

.timeline-bullets {
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
}

.timeline-bullets li {
  position: relative;
  padding-left: 1.25rem;
  font-size: 0.92rem;
  color: var(--text-secondary);
}

.timeline-bullets li::before {
  content: '▸';
  position: absolute;
  left: 0;
  color: var(--accent-primary);
  font-weight: bold;
}

.timeline-bullets li strong {
  color: var(--text-primary);
}

/* Subprojects inside Experience */
.exp-subprojects {
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
  margin-top: 1.25rem;
}

.subproject-box {
  padding: 1.1rem 1.25rem;
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
}

.subproject-head {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 0.4rem;
}

.subp-name {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--text-primary);
}

.subp-role {
  font-size: 0.78rem;
  font-family: var(--font-mono);
  color: var(--accent-primary);
}

.subp-desc {
  font-size: 0.88rem;
  color: var(--text-secondary);
  line-height: 1.55;
}

/* ==========================================================================
   Projects Section
   ========================================================================== */
.filter-wrapper {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
  margin-bottom: 2.5rem;
}

.filter-btn {
  padding: 0.55rem 1.15rem;
  border-radius: var(--radius-full);
  font-size: 0.88rem;
  font-weight: 600;
  color: var(--text-secondary);
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  transition: all var(--transition-fast);
}

.filter-btn:hover {
  color: var(--text-primary);
  border-color: var(--border-color-hover);
}

.filter-btn.active {
  background: var(--accent-primary);
  color: #FFFFFF;
  border-color: var(--accent-primary);
  box-shadow: 0 2px 10px rgba(59, 130, 246, 0.35);
}

.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
  gap: 1.75rem;
}

.project-box {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 1.85rem;
  display: flex;
  flex-direction: column;
  gap: 1rem;
  backdrop-filter: blur(12px);
  transition: transform var(--transition-normal), border-color var(--transition-normal), box-shadow var(--transition-normal), opacity var(--transition-fast);
}

.project-box:hover {
  transform: translateY(-6px);
  border-color: var(--accent-border);
  box-shadow: var(--shadow-md);
}

.project-box.hidden {
  display: none !important;
}

.project-badge-bar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 0.75rem;
  font-size: 0.8rem;
}

.p-category {
  font-weight: 700;
  color: var(--accent-primary);
}

.p-date {
  font-family: var(--font-mono);
  color: var(--text-muted);
}

.project-box-title {
  font-family: var(--font-heading);
  font-size: 1.22rem;
  font-weight: 700;
  color: var(--text-primary);
  line-height: 1.35;
}

.project-box-desc {
  font-size: 0.92rem;
  color: var(--text-secondary);
  line-height: 1.6;
  flex-grow: 1;
}

.project-highlights {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  padding: 0.85rem 1rem;
  background: var(--bg-tertiary);
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-color);
}

.ph-item {
  display: flex;
  flex-direction: column;
  gap: 0.15rem;
}

.ph-item strong {
  font-size: 0.78rem;
  color: var(--accent-primary);
}

.ph-item span {
  font-size: 0.84rem;
  color: var(--text-primary);
  line-height: 1.45;
}

.project-tech-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
}

.project-tech-tags span {
  font-size: 0.76rem;
  padding: 0.25rem 0.6rem;
  border-radius: var(--radius-full);
  background: var(--bg-tertiary);
  color: var(--text-secondary);
  border: 1px solid var(--border-color);
}

.project-actions {
  display: flex;
  align-items: center;
  gap: 0.65rem;
  margin-top: 0.5rem;
  flex-wrap: wrap;
}

.btn-modal-open {
  background: var(--accent-primary);
  color: #FFFFFF;
}
.btn-modal-open:hover {
  background: var(--accent-primary-hover);
  color: #FFFFFF;
}

/* ==========================================================================
   Education & Awards Section
   ========================================================================== */
.edu-awards-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3.5rem;
}

.col-heading {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-family: var(--font-heading);
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 1.5rem;
  padding-bottom: 0.75rem;
  border-bottom: 1px solid var(--border-color);
}

.col-icon {
  font-size: 1.4rem;
}

.edu-col, .awards-col {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.edu-card {
  padding: 1.5rem 1.6rem;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  transition: transform var(--transition-fast), border-color var(--transition-fast);
}

.edu-card:hover {
  transform: translateY(-3px);
  border-color: var(--accent-border);
}

.edu-card.highlight-border {
  border-color: var(--accent-border);
  background: linear-gradient(135deg, rgba(59, 130, 246, 0.08) 0%, var(--bg-card) 100%);
}

.edu-head {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 0.5rem;
}

.edu-degree-badge {
  font-size: 0.78rem;
  font-weight: 700;
  padding: 0.25rem 0.65rem;
  border-radius: var(--radius-full);
  background: var(--accent-soft);
  color: var(--accent-primary);
}

.degree-ms { background: rgba(139, 92, 246, 0.15); color: var(--accent-purple); }
.degree-bs { background: rgba(16, 185, 129, 0.15); color: #10B981; }

.edu-years {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--text-muted);
}

.edu-school {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 0.2rem;
}

.edu-major {
  font-size: 0.92rem;
  color: var(--text-secondary);
  margin-bottom: 0.35rem;
}

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

.edu-advisor strong {
  color: var(--accent-primary);
}

/* Awards Banner */
.award-banner {
  display: flex;
  gap: 1.25rem;
  padding: 1.4rem 1.5rem;
  background: linear-gradient(135deg, rgba(234, 179, 8, 0.12) 0%, var(--bg-card) 100%);
  border: 1px solid rgba(234, 179, 8, 0.3);
  border-radius: var(--radius-md);
  align-items: center;
}

.award-trophy {
  font-size: 2.2rem;
  flex-shrink: 0;
}

.award-title {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 0.25rem;
}

.award-org {
  font-size: 0.82rem;
  font-family: var(--font-mono);
  color: #EAB308;
  margin-bottom: 0.3rem;
}

.award-sub {
  font-size: 0.85rem;
  color: var(--text-secondary);
}

/* Certificate Grid */
.cert-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 0.85rem;
}

.cert-card {
  padding: 1rem 1.15rem;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
}

.cert-card:hover {
  border-color: var(--accent-border);
  transform: translateY(-2px);
}

.cert-name {
  font-size: 0.9rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 0.2rem;
}

.cert-meta {
  font-size: 0.76rem;
  color: var(--text-muted);
}

/* Training Section */
.mt-4 { margin-top: 1.5rem; }

.training-card {
  padding: 1.35rem 1.5rem;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
}

.training-head {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 0.75rem;
  flex-wrap: wrap;
  margin-bottom: 0.3rem;
}

.training-head strong {
  font-size: 0.98rem;
  color: var(--text-primary);
}

.training-badge {
  font-family: var(--font-mono);
  font-size: 0.76rem;
  font-weight: 700;
  color: #10B981;
  padding: 0.2rem 0.6rem;
  background: rgba(16, 185, 129, 0.12);
  border-radius: var(--radius-full);
}

.training-meta {
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-bottom: 0.6rem;
}

.training-desc {
  font-size: 0.88rem;
  color: var(--text-secondary);
  line-height: 1.55;
}

.training-small-list {
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
}

.tr-small-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0.75rem 1rem;
  background: var(--bg-tertiary);
  border-radius: var(--radius-sm);
  font-size: 0.86rem;
  border: 1px solid var(--border-color);
}

.tr-small-item span {
  font-weight: 600;
  color: var(--text-primary);
}

.tr-small-item em {
  font-style: normal;
  font-size: 0.76rem;
  color: var(--text-muted);
}

/* ==========================================================================
   Contact Section & Footer
   ========================================================================== */
.contact-card-wrap {
  max-width: 900px;
  margin: 0 auto;
}

.contact-card {
  padding: 3.5rem 3rem;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  backdrop-filter: blur(16px);
  text-align: center;
}

.contact-title {
  font-family: var(--font-heading);
  font-size: clamp(1.6rem, 3vw, 2.2rem);
  font-weight: 800;
  color: var(--text-primary);
  margin-bottom: 0.85rem;
}

.contact-desc {
  font-size: 1.05rem;
  color: var(--text-secondary);
  max-width: 620px;
  margin: 0 auto 2.5rem;
  line-height: 1.7;
}

.contact-info-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.25rem;
  margin-bottom: 2.5rem;
  text-align: left;
}

.contact-box {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 1.2rem 1.4rem;
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  position: relative;
  transition: all var(--transition-fast);
}

.contact-box:hover {
  border-color: var(--accent-border);
  transform: translateY(-2px);
}

.cb-icon {
  font-size: 1.6rem;
  flex-shrink: 0;
}

.cb-text {
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

.cb-label {
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-muted);
}

.cb-val {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-primary);
  text-overflow: ellipsis;
  overflow: hidden;
  white-space: nowrap;
}

.cb-val:hover {
  color: var(--accent-primary);
}

.cb-copy {
  margin-left: auto;
  font-size: 0.78rem;
  font-weight: 600;
  padding: 0.3rem 0.65rem;
  border-radius: var(--radius-sm);
  background: var(--accent-soft);
  color: var(--accent-primary);
  border: 1px solid var(--accent-border);
  transition: all var(--transition-fast);
}

.cb-copy:hover {
  background: var(--accent-primary);
  color: #FFFFFF;
}

.contact-footer-note {
  font-size: 0.88rem;
  color: var(--text-muted);
}

/* Footer */
.footer {
  padding: 2.5rem 0;
  border-top: 1px solid var(--border-color);
  background: var(--bg-primary);
}

.footer-container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1.5rem;
}

.footer-copy {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-primary);
}

.footer-sub {
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-top: 0.2rem;
}

.back-to-top {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.85rem;
  font-weight: 600;
  padding: 0.5rem 1rem;
  border-radius: var(--radius-full);
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  transition: all var(--transition-fast);
}

.back-to-top:hover {
  color: var(--accent-primary);
  border-color: var(--accent-border);
  transform: translateY(-2px);
}

/* ==========================================================================
   Project Detail Modal
   ========================================================================== */
.modal-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.75);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  z-index: 2000;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1.5rem;
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--transition-fast), visibility var(--transition-fast);
}

.modal-backdrop.open {
  opacity: 1;
  visibility: visible;
}

.modal-window {
  width: 100%;
  max-width: 780px;
  max-height: 90vh;
  overflow-y: auto;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  position: relative;
  padding: 2.5rem;
  transform: scale(0.95);
  transition: transform var(--transition-normal);
}

.modal-backdrop.open .modal-window {
  transform: scale(1);
}

.modal-close {
  position: absolute;
  top: 1.25rem;
  right: 1.25rem;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: var(--bg-tertiary);
  color: var(--text-primary);
  font-size: 1.4rem;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--border-color);
  transition: all var(--transition-fast);
}

.modal-close:hover {
  background: #EF4444;
  color: #FFFFFF;
  border-color: #EF4444;
}

.modal-header-tag {
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--accent-primary);
  margin-bottom: 0.4rem;
}

.modal-title {
  font-family: var(--font-heading);
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--text-primary);
  margin-bottom: 0.4rem;
  line-height: 1.3;
}

.modal-team-info {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: 1.5rem;
}

.modal-video-box {
  width: 100%;
  aspect-ratio: 16/9;
  border-radius: var(--radius-md);
  overflow: hidden;
  background: #000;
  margin-bottom: 1.5rem;
}

.modal-video-box iframe {
  width: 100%;
  height: 100%;
  border: none;
}

.modal-section-title {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text-primary);
  margin: 1.25rem 0 0.5rem;
}

.modal-text {
  font-size: 0.92rem;
  color: var(--text-secondary);
  line-height: 1.65;
}

.modal-list {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  margin-top: 0.5rem;
}

.modal-list li {
  position: relative;
  padding-left: 1.25rem;
  font-size: 0.9rem;
  color: var(--text-secondary);
}

.modal-list li::before {
  content: '✓';
  position: absolute;
  left: 0;
  color: var(--accent-primary);
  font-weight: bold;
}

.modal-footer-actions {
  display: flex;
  gap: 0.85rem;
  margin-top: 2rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border-color);
}

/* ==========================================================================
   Toast Notification
   ========================================================================== */
.toast-notification {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  z-index: 3000;
  background: #10B981;
  color: #FFFFFF;
  padding: 0.75rem 1.4rem;
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-size: 0.9rem;
  font-weight: 600;
  box-shadow: 0 8px 24px rgba(16, 185, 129, 0.4);
  transform: translateY(100px);
  opacity: 0;
  transition: transform var(--transition-normal), opacity var(--transition-normal);
  pointer-events: none;
}

.toast-notification.show {
  transform: translateY(0);
  opacity: 1;
}

.exp-bridge-note {
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
  margin-top: 1rem;
  padding: 0.9rem 1.15rem;
  background: var(--accent-soft);
  border: 1px solid var(--accent-border);
  border-radius: var(--radius-md);
  font-size: 0.86rem;
  color: var(--text-primary);
  line-height: 1.55;
}

.exp-bridge-note strong {
  color: var(--accent-primary);
}

.bridge-icon {
  font-size: 1.1rem;
  flex-shrink: 0;
}

/* ==========================================================================
   Responsive Breakpoints
   ========================================================================== */
@media (max-width: 1024px) {
  .hero-container {
    grid-template-columns: 1fr;
    gap: 3rem;
  }
  
  .profile-card-wrapper {
    max-width: 300px;
  }
  
  .about-grid, .edu-awards-grid {
    grid-template-columns: 1fr;
    gap: 3rem;
  }
  
  .research-pillars, .skills-wrapper {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 768px) {
  .section {
    padding: 4.5rem 0;
  }

  .hero-section {
    padding: 3.5rem 0 3rem;
  }

  .nav-toggle {
    display: flex;
  }

  .nav-links {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--bg-secondary);
    border-bottom: 1px solid transparent;
    flex-direction: column;
    align-items: stretch;
    padding: 0 1.5rem;
    gap: 0.35rem;
    max-height: 0;
    opacity: 0;
    visibility: hidden;
    overflow: hidden;
    transition: max-height 0.3s ease, padding 0.3s ease, opacity 0.2s ease, visibility 0.3s ease;
  }

  .nav-links.open {
    padding: 1rem 1.5rem 1.25rem;
    max-height: 420px;
    opacity: 1;
    visibility: visible;
    border-bottom: 1px solid var(--border-color);
    box-shadow: var(--shadow-md);
  }

  .nav-item {
    padding: 0.75rem 1rem;
  }

  .hero-title {
    font-size: 2.1rem;
  }

  .about-stats {
    grid-template-columns: 1fr;
  }

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

  .contact-info-grid, .cert-grid {
    grid-template-columns: 1fr;
  }

  .contact-card {
    padding: 2.5rem 1.5rem;
  }

  .modal-window {
    padding: 1.75rem 1.25rem;
  }
}