/* ==========================================================================
   PORTFOLIO DESIGN SYSTEM & DARK THEME STYLES
   Author: Dohyun Kim (AI Researcher & Software Engineer)
   ========================================================================== */

/* --------------------------------------------------------------------------
   1. CSS Reset & Variables
   -------------------------------------------------------------------------- */
:root {
  /* Color Palette */
  --bg-dark: #070a11;
  --bg-dark-secondary: #0d121f;
  --bg-card: rgba(16, 24, 40, 0.65);
  --bg-card-hover: rgba(23, 34, 56, 0.85);
  --bg-input: rgba(11, 18, 33, 0.8);

  /* Borders & Dividers */
  --border-subtle: rgba(255, 255, 255, 0.08);
  --border-focus: rgba(99, 102, 241, 0.6);
  --border-hover: rgba(56, 189, 248, 0.4);

  /* Accents & Gradients */
  --accent-cyan: #38bdf8;
  --accent-blue: #3b82f6;
  --accent-indigo: #6366f1;
  --accent-purple: #a855f7;
  --accent-pink: #ec4899;
  --accent-emerald: #10b981;
  --accent-amber: #f59e0b;

  --gradient-primary: linear-gradient(135deg, #38bdf8 0%, #6366f1 50%, #a855f7 100%);
  --gradient-glow: linear-gradient(135deg, rgba(56, 189, 248, 0.25), rgba(99, 102, 241, 0.25));
  --gradient-gold: linear-gradient(135deg, #fbbf24 0%, #f59e0b 50%, #d97706 100%);

  /* Typography Colors */
  --text-main: #f8fafc;
  --text-muted: #94a3b8;
  --text-dim: #64748b;
  --text-inverse: #090d16;

  /* Typography Families */
  --font-sans: 'Pretendard', 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-heading: 'Outfit', 'Pretendard', sans-serif;
  --font-mono: 'Fira Code', monospace;

  /* Transitions & Shadows */
  --transition-fast: 0.18s ease;
  --transition-normal: 0.3s cubic-bezier(0.16, 1, 0.3, 1);
  --transition-slow: 0.5s cubic-bezier(0.16, 1, 0.3, 1);
  
  --shadow-sm: 0 4px 12px rgba(0, 0, 0, 0.25);
  --shadow-md: 0 10px 30px -10px rgba(0, 0, 0, 0.5);
  --shadow-lg: 0 20px 40px -15px rgba(0, 0, 0, 0.7);
  --shadow-glow: 0 0 35px rgba(99, 102, 241, 0.25);

  /* Layout */
  --header-height: 76px;
  --container-max-width: 1200px;
  --border-radius-sm: 8px;
  --border-radius-md: 14px;
  --border-radius-lg: 20px;
  --border-radius-pill: 9999px;
}

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

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

body {
  font-family: var(--font-sans);
  background-color: var(--bg-dark);
  color: var(--text-main);
  line-height: 1.65;
  overflow-x: hidden;
  position: relative;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  background-image: 
    radial-gradient(circle at 15% 20%, rgba(56, 189, 248, 0.05) 0%, transparent 40%),
    radial-gradient(circle at 85% 70%, rgba(168, 85, 247, 0.05) 0%, transparent 45%);
}

/* --------------------------------------------------------------------------
   2. Background Ambient Glow Orbs
   -------------------------------------------------------------------------- */
.ambient-glow {
  position: fixed;
  border-radius: 50%;
  filter: blur(120px);
  pointer-events: none;
  z-index: 0;
  opacity: 0.45;
  animation: floatOrb 20s infinite alternate ease-in-out;
}

.glow-1 {
  width: 500px;
  height: 500px;
  background: radial-gradient(circle, rgba(56, 189, 248, 0.35) 0%, rgba(99, 102, 241, 0.1) 70%, transparent 100%);
  top: -100px;
  left: -100px;
}

.glow-2 {
  width: 550px;
  height: 550px;
  background: radial-gradient(circle, rgba(168, 85, 247, 0.3) 0%, rgba(59, 130, 246, 0.08) 70%, transparent 100%);
  top: 40%;
  right: -150px;
  animation-duration: 25s;
  animation-delay: -5s;
}

.glow-3 {
  width: 450px;
  height: 450px;
  background: radial-gradient(circle, rgba(16, 185, 129, 0.25) 0%, rgba(56, 189, 248, 0.05) 70%, transparent 100%);
  bottom: 5%;
  left: 10%;
  animation-duration: 22s;
  animation-delay: -10s;
}

@keyframes floatOrb {
  0% { transform: translate(0, 0) scale(1); }
  50% { transform: translate(60px, 40px) scale(1.1); }
  100% { transform: translate(-40px, 70px) scale(0.95); }
}

/* --------------------------------------------------------------------------
   3. Utilities & Global Components
   -------------------------------------------------------------------------- */
.container {
  width: 100%;
  max-width: var(--container-max-width);
  margin-left: auto;
  margin-right: auto;
  padding-left: 1.5rem;
  padding-right: 1.5rem;
  position: relative;
  z-index: 1;
}

.section-padding {
  padding-top: 6.5rem;
  padding-bottom: 6.5rem;
}

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

/* Glass Panel Utility */
.glass-panel {
  background: var(--bg-card);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border: 1px solid var(--border-subtle);
  border-radius: var(--border-radius-md);
  box-shadow: var(--shadow-md);
  transition: transform var(--transition-normal), border-color var(--transition-normal), box-shadow var(--transition-normal);
}

.glass-panel:hover {
  border-color: var(--border-hover);
  box-shadow: var(--shadow-lg), var(--shadow-glow);
}

/* Gradient Text */
.gradient-text {
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  display: inline-block;
}

/* Section Header Typography */
.section-header {
  margin-bottom: 3.5rem;
}

.section-tag {
  display: inline-block;
  font-family: var(--font-heading);
  font-size: 0.85rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--accent-cyan);
  background: rgba(56, 189, 248, 0.1);
  border: 1px solid rgba(56, 189, 248, 0.25);
  padding: 0.35rem 1rem;
  border-radius: var(--border-radius-pill);
  margin-bottom: 1rem;
}

.section-title {
  font-family: var(--font-heading);
  font-size: clamp(2rem, 3.5vw, 2.75rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--text-main);
  margin-bottom: 1rem;
}

.section-subtitle {
  font-size: 1.1rem;
  color: var(--text-muted);
  max-width: 680px;
  margin-left: auto;
  margin-right: auto;
  line-height: 1.7;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  font-family: var(--font-sans);
  font-size: 0.95rem;
  font-weight: 600;
  padding: 0.8rem 1.6rem;
  border-radius: var(--border-radius-pill);
  text-decoration: none;
  cursor: pointer;
  transition: all var(--transition-normal);
  border: 1px solid transparent;
  outline: none;
  white-space: nowrap;
}

.btn:active {
  transform: scale(0.97);
}

.btn-primary {
  background: var(--gradient-primary);
  color: #ffffff;
  box-shadow: 0 4px 20px rgba(99, 102, 241, 0.4);
}

.btn-primary:hover {
  box-shadow: 0 6px 28px rgba(99, 102, 241, 0.6);
  transform: translateY(-2px);
}

.btn-secondary {
  background: rgba(255, 255, 255, 0.06);
  color: var(--text-main);
  border-color: rgba(255, 255, 255, 0.15);
}

.btn-secondary:hover {
  background: rgba(255, 255, 255, 0.12);
  border-color: rgba(255, 255, 255, 0.3);
  transform: translateY(-2px);
}

.btn-glass {
  background: rgba(15, 23, 42, 0.7);
  backdrop-filter: blur(10px);
  color: var(--text-main);
  border-color: var(--border-subtle);
}

.btn-glass:hover {
  border-color: var(--accent-cyan);
  background: rgba(15, 23, 42, 0.9);
  color: var(--accent-cyan);
  transform: translateY(-2px);
}

.btn-outline {
  background: transparent;
  color: var(--accent-cyan);
  border: 1px solid rgba(56, 189, 248, 0.4);
}

.btn-outline:hover {
  background: rgba(56, 189, 248, 0.12);
  border-color: var(--accent-cyan);
  color: #ffffff;
}

.btn-sm {
  font-size: 0.85rem;
  padding: 0.5rem 1.1rem;
}

.btn-block {
  width: 100%;
}

/* --------------------------------------------------------------------------
   4. Scroll Progress Bar
   -------------------------------------------------------------------------- */
.scroll-progress-bar {
  position: fixed;
  top: 0;
  left: 0;
  height: 3px;
  width: 0%;
  background: var(--gradient-primary);
  z-index: 1000;
  transition: width 0.1s ease-out;
}

/* --------------------------------------------------------------------------
   5. Site Header & Navigation
   -------------------------------------------------------------------------- */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: var(--header-height);
  z-index: 100;
  transition: background-color var(--transition-normal), backdrop-filter var(--transition-normal), border-bottom var(--transition-normal);
}

.site-header.scrolled {
  background: rgba(7, 10, 17, 0.82);
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
  border-bottom: 1px solid var(--border-subtle);
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
}

.header-container {
  max-width: var(--container-max-width);
  margin: 0 auto;
  height: 100%;
  padding: 0 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand-logo {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  text-decoration: none;
}

.logo-symbol {
  font-family: var(--font-mono);
  font-size: 1rem;
  font-weight: 700;
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  padding: 0.2rem 0.5rem;
  border: 1px solid rgba(99, 102, 241, 0.3);
  border-radius: var(--border-radius-sm);
  background-color: rgba(99, 102, 241, 0.08);
}

.logo-text {
  font-family: var(--font-heading);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-main);
  letter-spacing: -0.01em;
}

.desktop-nav {
  display: block;
}

.nav-list {
  display: flex;
  align-items: center;
  list-style: none;
  gap: 1.75rem;
}

.nav-link {
  font-size: 0.92rem;
  font-weight: 500;
  color: var(--text-muted);
  text-decoration: none;
  transition: color var(--transition-fast);
  position: relative;
  padding: 0.4rem 0;
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0%;
  height: 2px;
  background: var(--gradient-primary);
  transition: width var(--transition-normal);
  border-radius: 2px;
}

.nav-link:hover,
.nav-link.active {
  color: var(--text-main);
}

.nav-link:hover::after,
.nav-link.active::after {
  width: 100%;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.mobile-toggle-btn {
  display: none;
  flex-direction: column;
  justify-content: space-around;
  width: 38px;
  height: 38px;
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--border-subtle);
  border-radius: var(--border-radius-sm);
  padding: 9px;
  cursor: pointer;
  transition: background var(--transition-fast);
}

.mobile-toggle-btn:hover {
  background: rgba(255, 255, 255, 0.1);
}

.hamburger-bar {
  display: block;
  width: 100%;
  height: 2px;
  background: var(--text-main);
  border-radius: 2px;
  transition: all var(--transition-fast);
}

.mobile-toggle-btn.active .hamburger-bar:nth-child(1) {
  transform: translateY(6px) rotate(45deg);
}

.mobile-toggle-btn.active .hamburger-bar:nth-child(2) {
  opacity: 0;
}

.mobile-toggle-btn.active .hamburger-bar:nth-child(3) {
  transform: translateY(-6px) rotate(-45deg);
}

/* Mobile Nav Drawer */
.mobile-nav {
  position: fixed;
  top: var(--header-height);
  left: 0;
  width: 100%;
  height: calc(100vh - var(--header-height));
  background: rgba(7, 10, 17, 0.95);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border-subtle);
  transform: translateY(-100%);
  opacity: 0;
  visibility: hidden;
  transition: all var(--transition-normal);
  overflow-y: auto;
  z-index: 99;
}

.mobile-nav.open {
  transform: translateY(0);
  opacity: 1;
  visibility: visible;
}

.mobile-nav-inner {
  padding: 2.5rem 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 2rem;
}

.mobile-nav-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.mobile-nav-link {
  display: flex;
  align-items: center;
  gap: 1rem;
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--text-muted);
  text-decoration: none;
  padding: 0.75rem 0;
  border-bottom: 1px solid rgba(255, 255, 255, 0.05);
  transition: color var(--transition-fast);
}

.mobile-nav-link i {
  font-size: 1.1rem;
  color: var(--accent-cyan);
  width: 24px;
}

.mobile-nav-link:hover,
.mobile-nav-link.active {
  color: var(--text-main);
}

/* --------------------------------------------------------------------------
   6. Hero Section
   -------------------------------------------------------------------------- */
.hero-section {
  padding-top: calc(var(--header-height) + 3.5rem);
  min-height: 90vh;
  display: flex;
  align-items: center;
}

.hero-container {
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  align-items: center;
  gap: 3.5rem;
}

.status-badge-wrapper {
  margin-bottom: 1.5rem;
}

.status-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  background: rgba(16, 185, 129, 0.1);
  border: 1px solid rgba(16, 185, 129, 0.3);
  padding: 0.4rem 1rem;
  border-radius: var(--border-radius-pill);
  font-size: 0.85rem;
  font-weight: 600;
  color: #34d399;
}

.status-dot {
  width: 8px;
  height: 8px;
  background: #10b981;
  border-radius: 50%;
  box-shadow: 0 0 10px #10b981;
  animation: pulseDot 2s infinite ease-in-out;
}

@keyframes pulseDot {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.4; transform: scale(0.85); }
}

.hero-title {
  font-family: var(--font-heading);
  font-size: clamp(2.4rem, 4.2vw, 3.75rem);
  font-weight: 800;
  line-height: 1.2;
  letter-spacing: -0.03em;
  color: var(--text-main);
  margin-bottom: 1.5rem;
}

.hero-description {
  font-size: 1.15rem;
  color: var(--text-muted);
  line-height: 1.75;
  margin-bottom: 2.2rem;
  max-width: 620px;
}

.hero-description strong {
  color: var(--text-main);
}

.hero-cta-group {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 1rem;
  margin-bottom: 3.5rem;
}

.hero-stats-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1.25rem;
  padding-top: 1.75rem;
  border-top: 1px solid var(--border-subtle);
}

.stat-card {
  display: flex;
  flex-direction: column;
}

.stat-number {
  font-family: var(--font-heading);
  font-size: 2rem;
  font-weight: 800;
  color: var(--text-main);
  line-height: 1.1;
  margin-bottom: 0.3rem;
}

.stat-accent {
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  font-size: 1.5rem;
}

.stat-label {
  font-size: 0.8rem;
  color: var(--text-muted);
  line-height: 1.35;
}

/* Hero Visual & Profile Card */
.hero-visual {
  display: flex;
  justify-content: center;
}

.profile-card-wrapper {
  position: relative;
  width: 100%;
  max-width: 420px;
}

.profile-card-glow {
  position: absolute;
  inset: -15px;
  background: var(--gradient-primary);
  filter: blur(40px);
  opacity: 0.35;
  border-radius: var(--border-radius-lg);
  z-index: 0;
  transition: opacity var(--transition-slow);
}

.profile-card-wrapper:hover .profile-card-glow {
  opacity: 0.55;
}

.profile-card {
  position: relative;
  background: rgba(16, 24, 40, 0.7);
  backdrop-filter: blur(24px);
  -webkit-backdrop-filter: blur(24px);
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: var(--border-radius-lg);
  overflow: hidden;
  box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.7);
  z-index: 1;
}

.profile-img-container {
  position: relative;
  width: 100%;
  height: 380px;
  overflow: hidden;
  background: #0d121f;
}

.profile-image {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: top center;
  transition: transform var(--transition-slow);
}

.profile-card:hover .profile-image {
  transform: scale(1.03);
}

.profile-overlay-badge {
  position: absolute;
  top: 1rem;
  right: 1rem;
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  background: rgba(15, 23, 42, 0.8);
  backdrop-filter: blur(12px);
  border: 1px solid rgba(255, 255, 255, 0.15);
  padding: 0.35rem 0.85rem;
  border-radius: var(--border-radius-pill);
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--accent-cyan);
}

.profile-card-footer {
  padding: 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-top: 1px solid var(--border-subtle);
}

.profile-name {
  font-family: var(--font-heading);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-main);
}

.profile-eng {
  font-size: 0.85rem;
  font-weight: 400;
  color: var(--text-muted);
  margin-left: 0.3rem;
}

.profile-role {
  font-size: 0.85rem;
  color: var(--text-dim);
  margin-top: 0.2rem;
}

.profile-social-links {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.social-icon-btn {
  width: 36px;
  height: 36px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--border-subtle);
  border-radius: 50%;
  color: var(--text-muted);
  text-decoration: none;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.social-icon-btn:hover {
  background: rgba(56, 189, 248, 0.15);
  border-color: var(--accent-cyan);
  color: var(--accent-cyan);
  transform: translateY(-2px);
}

/* Floating Tech Badges */
.floating-tech-badge {
  position: absolute;
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  background: rgba(15, 23, 42, 0.85);
  backdrop-filter: blur(14px);
  border: 1px solid rgba(255, 255, 255, 0.15);
  padding: 0.65rem 1.1rem;
  border-radius: var(--border-radius-pill);
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.5);
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-main);
  z-index: 2;
  animation: floatBadge 6s infinite ease-in-out;
}

.floating-tech-badge i {
  color: var(--accent-cyan);
}

.badge-top-right {
  top: -15px;
  right: -25px;
}

.badge-bottom-left {
  bottom: 85px;
  left: -35px;
  animation-delay: -3s;
}

.badge-bottom-left i {
  color: var(--accent-purple);
}

@keyframes floatBadge {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-8px); }
}

/* --------------------------------------------------------------------------
   7. About Section
   -------------------------------------------------------------------------- */
.about-grid {
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  gap: 2rem;
}

.about-card {
  padding: 2.25rem;
}

.card-icon-badge {
  width: 48px;
  height: 48px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background: rgba(99, 102, 241, 0.12);
  border: 1px solid rgba(99, 102, 241, 0.3);
  border-radius: var(--border-radius-sm);
  color: var(--accent-indigo);
  font-size: 1.25rem;
  margin-bottom: 1.5rem;
}

.card-title {
  font-family: var(--font-heading);
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 1.2rem;
  display: flex;
  align-items: center;
  gap: 0.6rem;
}

.card-title i {
  color: var(--accent-cyan);
  font-size: 1.1rem;
}

.card-text {
  font-size: 1rem;
  color: var(--text-muted);
  line-height: 1.8;
  margin-bottom: 1.25rem;
}

.card-text strong {
  color: var(--text-main);
}

.education-block {
  margin-top: 2rem;
  padding-top: 1.75rem;
  border-top: 1px solid var(--border-subtle);
}

.sub-heading {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--text-main);
  margin-bottom: 1.25rem;
  display: flex;
  align-items: center;
  gap: 0.6rem;
}

.sub-heading i {
  color: var(--accent-indigo);
}

.education-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.edu-item {
  display: flex;
  gap: 1.25rem;
}

.edu-year {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--accent-cyan);
  background: rgba(56, 189, 248, 0.1);
  padding: 0.2rem 0.6rem;
  border-radius: var(--border-radius-sm);
  height: fit-content;
  white-space: nowrap;
}

.edu-detail {
  font-size: 0.95rem;
  color: var(--text-main);
  line-height: 1.5;
}

.edu-lab {
  display: block;
  font-size: 0.85rem;
  color: var(--text-dim);
  margin-top: 0.2rem;
}

.about-side-column {
  display: flex;
  flex-direction: column;
  gap: 2rem;
}

.interests-grid {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.interest-item {
  display: flex;
  gap: 1rem;
  align-items: flex-start;
}

.interest-icon {
  width: 38px;
  height: 38px;
  min-width: 38px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(56, 189, 248, 0.1);
  border: 1px solid rgba(56, 189, 248, 0.25);
  border-radius: var(--border-radius-sm);
  color: var(--accent-cyan);
  font-size: 1rem;
}

.interest-item h4 {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-main);
  margin-bottom: 0.25rem;
}

.interest-item p {
  font-size: 0.88rem;
  color: var(--text-muted);
  line-height: 1.5;
}

.skills-category {
  margin-bottom: 1.25rem;
}

.skills-category:last-child {
  margin-bottom: 0;
}

.category-name {
  display: block;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-dim);
  margin-bottom: 0.6rem;
}

.tags-group {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.skill-tag {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--text-muted);
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--border-subtle);
  padding: 0.35rem 0.75rem;
  border-radius: var(--border-radius-sm);
  transition: all var(--transition-fast);
}

.skill-tag:hover {
  background: rgba(99, 102, 241, 0.15);
  border-color: var(--accent-indigo);
  color: #ffffff;
}

/* --------------------------------------------------------------------------
   8. Experience Timeline Section
   -------------------------------------------------------------------------- */
.timeline-container {
  position: relative;
  max-width: 900px;
  margin: 0 auto;
  padding: 1.5rem 0;
}

.timeline-line {
  position: absolute;
  top: 0;
  bottom: 0;
  left: 28px;
  width: 2px;
  background: linear-gradient(to bottom, var(--accent-cyan), var(--accent-indigo), var(--accent-purple));
  opacity: 0.4;
}

.timeline-item {
  position: relative;
  margin-bottom: 3rem;
  padding-left: 70px;
}

.timeline-item:last-child {
  margin-bottom: 0;
}

.timeline-marker {
  position: absolute;
  left: 10px;
  top: 0;
  width: 38px;
  height: 38px;
  border-radius: 50%;
  background: var(--bg-dark-secondary);
  border: 2px solid var(--accent-indigo);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--accent-cyan);
  font-size: 0.95rem;
  box-shadow: 0 0 15px rgba(99, 102, 241, 0.4);
  z-index: 2;
  transition: transform var(--transition-normal);
}

.timeline-item:hover .timeline-marker {
  transform: scale(1.15);
  border-color: var(--accent-cyan);
  box-shadow: 0 0 20px rgba(56, 189, 248, 0.6);
}

.timeline-content {
  padding: 2rem;
}

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

.period-badge {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--accent-cyan);
  background: rgba(56, 189, 248, 0.1);
  padding: 0.2rem 0.65rem;
  border-radius: var(--border-radius-sm);
  margin-bottom: 0.5rem;
}

.job-title {
  font-family: var(--font-heading);
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--text-main);
  line-height: 1.3;
}

.company-name {
  font-size: 1rem;
  font-weight: 500;
  color: var(--accent-indigo);
  margin-top: 0.25rem;
}

.work-badge {
  font-size: 0.78rem;
  color: var(--text-dim);
  background: rgba(255, 255, 255, 0.05);
  padding: 0.25rem 0.65rem;
  border-radius: var(--border-radius-pill);
  border: 1px solid var(--border-subtle);
  white-space: nowrap;
}

.timeline-desc {
  font-size: 0.98rem;
  color: var(--text-muted);
  line-height: 1.7;
  margin-bottom: 1.25rem;
}

.achievement-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  margin-bottom: 1.5rem;
}

.achievement-list li {
  position: relative;
  padding-left: 1.4rem;
  font-size: 0.92rem;
  color: var(--text-muted);
  line-height: 1.6;
}

.achievement-list li::before {
  content: '▹';
  position: absolute;
  left: 0;
  color: var(--accent-cyan);
  font-weight: 700;
}

.achievement-list strong {
  color: var(--text-main);
}

.tech-tags-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  padding-top: 1rem;
  border-top: 1px solid var(--border-subtle);
}

.tech-tags-list .tag {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-muted);
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid var(--border-subtle);
  padding: 0.25rem 0.6rem;
  border-radius: var(--border-radius-sm);
}

/* --------------------------------------------------------------------------
   9. Publications Section
   -------------------------------------------------------------------------- */
.filter-controls {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-bottom: 2.75rem;
}

.filter-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--font-sans);
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-muted);
  background: rgba(16, 24, 40, 0.6);
  border: 1px solid var(--border-subtle);
  padding: 0.6rem 1.25rem;
  border-radius: var(--border-radius-pill);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.filter-btn i {
  font-size: 0.85rem;
}

.filter-btn:hover {
  color: var(--text-main);
  border-color: rgba(255, 255, 255, 0.25);
  background: rgba(23, 34, 56, 0.8);
}

.filter-btn.active {
  color: #ffffff;
  background: var(--gradient-primary);
  border-color: transparent;
  box-shadow: 0 4px 15px rgba(99, 102, 241, 0.35);
}

.publications-grid {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  max-width: 960px;
  margin: 0 auto;
}

.pub-card {
  padding: 2rem;
  transition: all var(--transition-normal);
}

.pub-card.hide {
  display: none;
}

.pub-card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 0.75rem;
}

.pub-badge-group {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.5rem;
}

.pub-type-badge {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 600;
  padding: 0.25rem 0.65rem;
  border-radius: var(--border-radius-sm);
}

.pub-type-badge.conf {
  color: var(--accent-cyan);
  background: rgba(56, 189, 248, 0.12);
  border: 1px solid rgba(56, 189, 248, 0.25);
}

.pub-type-badge.journal {
  color: var(--accent-indigo);
  background: rgba(99, 102, 241, 0.12);
  border: 1px solid rgba(99, 102, 241, 0.25);
}

.pub-type-badge.patent {
  color: var(--accent-emerald);
  background: rgba(16, 185, 129, 0.12);
  border: 1px solid rgba(16, 185, 129, 0.25);
}

.pub-highlight-badge {
  font-size: 0.75rem;
  font-weight: 600;
  color: #f59e0b;
  background: rgba(245, 158, 11, 0.1);
  border: 1px solid rgba(245, 158, 11, 0.25);
  padding: 0.2rem 0.55rem;
  border-radius: var(--border-radius-pill);
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
}

.pub-highlight-badge.highlight-gold {
  color: #fcd34d;
  background: rgba(251, 191, 36, 0.12);
  border-color: rgba(251, 191, 36, 0.3);
}

.pub-year {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-dim);
}

.citation-count {
  font-size: 0.8rem;
  color: var(--text-muted);
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
}

.citation-count i {
  color: var(--accent-cyan);
}

.pub-title {
  font-family: var(--font-heading);
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--text-main);
  line-height: 1.4;
  margin-bottom: 0.6rem;
}

.pub-authors {
  font-size: 0.95rem;
  color: var(--text-muted);
  margin-bottom: 0.35rem;
}

.author-me {
  color: var(--accent-cyan);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.pub-venue {
  font-size: 0.9rem;
  color: var(--text-dim);
  margin-bottom: 1.25rem;
}

.pub-abstract {
  background: rgba(11, 18, 33, 0.65);
  border: 1px solid var(--border-subtle);
  border-radius: var(--border-radius-sm);
  padding: 1.25rem;
  margin-bottom: 1.25rem;
  font-size: 0.9rem;
  color: var(--text-muted);
  line-height: 1.7;
  display: none;
  animation: fadeIn 0.3s ease;
}

.pub-abstract.open {
  display: block;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(-5px); }
  to { opacity: 1; transform: translateY(0); }
}

.pub-actions {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.65rem;
  padding-top: 1rem;
  border-top: 1px solid var(--border-subtle);
}

.action-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  font-family: var(--font-sans);
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--text-muted);
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--border-subtle);
  padding: 0.4rem 0.85rem;
  border-radius: var(--border-radius-sm);
  text-decoration: none;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.action-btn:hover {
  background: rgba(255, 255, 255, 0.1);
  color: var(--text-main);
  border-color: rgba(255, 255, 255, 0.2);
}

.action-btn.toggle-abstract-btn.open i {
  transform: rotate(180deg);
}

.action-btn.toggle-abstract-btn i {
  transition: transform var(--transition-fast);
}

.action-btn.pdf-btn:hover {
  color: #ef4444;
  border-color: rgba(239, 68, 68, 0.4);
  background: rgba(239, 68, 68, 0.1);
}

.action-btn.bibtex-btn:hover {
  color: var(--accent-purple);
  border-color: rgba(168, 85, 247, 0.4);
  background: rgba(168, 85, 247, 0.1);
}

.action-btn.doi-btn:hover {
  color: var(--accent-cyan);
  border-color: rgba(56, 189, 248, 0.4);
  background: rgba(56, 189, 248, 0.1);
}

/* --------------------------------------------------------------------------
   10. Awards Section
   -------------------------------------------------------------------------- */
.awards-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.75rem;
}

.award-card {
  padding: 2.25rem;
  display: flex;
  gap: 1.5rem;
  position: relative;
  overflow: hidden;
}

.award-featured {
  border-color: rgba(245, 158, 11, 0.3);
}

.award-featured::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 4px;
  height: 100%;
  background: var(--gradient-gold);
}

.award-trophy-icon {
  width: 54px;
  height: 54px;
  min-width: 54px;
  border-radius: var(--border-radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
}

.trophy-gold {
  background: rgba(251, 191, 36, 0.15);
  border: 1px solid rgba(251, 191, 36, 0.4);
  color: #fbbf24;
  box-shadow: 0 0 20px rgba(251, 191, 36, 0.2);
}

.trophy-blue {
  background: rgba(59, 130, 246, 0.15);
  border: 1px solid rgba(59, 130, 246, 0.4);
  color: #60a5fa;
  box-shadow: 0 0 20px rgba(59, 130, 246, 0.2);
}

.trophy-purple {
  background: rgba(168, 85, 247, 0.15);
  border: 1px solid rgba(168, 85, 247, 0.4);
  color: #c084fc;
  box-shadow: 0 0 20px rgba(168, 85, 247, 0.2);
}

.trophy-cyan {
  background: rgba(56, 189, 248, 0.15);
  border: 1px solid rgba(56, 189, 248, 0.4);
  color: #38bdf8;
  box-shadow: 0 0 20px rgba(56, 189, 248, 0.2);
}

.award-content {
  flex: 1;
}

.award-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 0.6rem;
}

.award-year {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--text-dim);
}

.award-badge {
  font-size: 0.75rem;
  font-weight: 700;
  padding: 0.2rem 0.6rem;
  border-radius: var(--border-radius-pill);
}

.award-badge.gold {
  color: #fbbf24;
  background: rgba(251, 191, 36, 0.12);
  border: 1px solid rgba(251, 191, 36, 0.3);
}

.award-badge.blue {
  color: #60a5fa;
  background: rgba(59, 130, 246, 0.12);
  border: 1px solid rgba(59, 130, 246, 0.3);
}

.award-badge.purple {
  color: #c084fc;
  background: rgba(168, 85, 247, 0.12);
  border: 1px solid rgba(168, 85, 247, 0.3);
}

.award-badge.cyan {
  color: #38bdf8;
  background: rgba(56, 189, 248, 0.12);
  border: 1px solid rgba(56, 189, 248, 0.3);
}

.award-title {
  font-family: var(--font-heading);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 0.3rem;
  line-height: 1.35;
}

.award-issuer {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--accent-cyan);
  margin-bottom: 0.75rem;
}

.award-desc {
  font-size: 0.9rem;
  color: var(--text-muted);
  line-height: 1.6;
}

/* --------------------------------------------------------------------------
   11. Contact Section & Interactive Form
   -------------------------------------------------------------------------- */
.contact-grid {
  display: grid;
  grid-template-columns: 0.9fr 1.1fr;
  gap: 2.5rem;
  align-items: stretch;
}

.contact-info-card {
  padding: 2.5rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.info-card-title {
  font-family: var(--font-heading);
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--text-main);
  line-height: 1.35;
  margin-bottom: 1rem;
}

.info-card-desc {
  font-size: 0.98rem;
  color: var(--text-muted);
  line-height: 1.7;
  margin-bottom: 2rem;
}

.info-card-desc strong {
  color: var(--accent-cyan);
}

.contact-methods-list {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  margin-bottom: 2rem;
}

.contact-method-item {
  display: flex;
  align-items: flex-start;
  gap: 1.25rem;
}

.method-icon {
  width: 42px;
  height: 42px;
  min-width: 42px;
  border-radius: var(--border-radius-sm);
  background: rgba(99, 102, 241, 0.12);
  border: 1px solid rgba(99, 102, 241, 0.3);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--accent-indigo);
  font-size: 1.1rem;
}

.method-text {
  display: flex;
  flex-direction: column;
  gap: 0.2rem;
}

.method-label {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-dim);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.method-value {
  font-size: 0.98rem;
  font-weight: 600;
  color: var(--text-main);
}

.copyable-email-wrapper {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  flex-wrap: wrap;
}

.mini-copy-btn {
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid var(--border-subtle);
  border-radius: 6px;
  color: var(--text-muted);
  padding: 0.3rem 0.5rem;
  cursor: pointer;
  font-size: 0.85rem;
  transition: all var(--transition-fast);
}

.mini-copy-btn:hover {
  background: rgba(56, 189, 248, 0.15);
  border-color: var(--accent-cyan);
  color: var(--accent-cyan);
}

.info-social-block {
  padding-top: 1.75rem;
  border-top: 1px solid var(--border-subtle);
}

.social-block-title {
  display: block;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-dim);
  margin-bottom: 0.85rem;
}

.social-buttons-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
}

.social-tag-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--text-muted);
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--border-subtle);
  padding: 0.45rem 0.9rem;
  border-radius: var(--border-radius-pill);
  text-decoration: none;
  transition: all var(--transition-fast);
}

.social-tag-btn:hover {
  background: rgba(99, 102, 241, 0.15);
  border-color: var(--accent-indigo);
  color: #ffffff;
}

/* Form Styles */
.contact-form-wrapper {
  padding: 2.5rem;
}

.contact-form {
  display: flex;
  flex-direction: column;
  gap: 1.4rem;
}

.form-row {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.25rem;
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
}

.form-label {
  font-size: 0.88rem;
  font-weight: 600;
  color: var(--text-main);
}

.required-star {
  color: #f43f5e;
}

.input-wrapper {
  position: relative;
  display: flex;
  align-items: center;
}

.input-icon {
  position: absolute;
  left: 1.1rem;
  color: var(--text-dim);
  font-size: 0.95rem;
  pointer-events: none;
  transition: color var(--transition-fast);
}

.textarea-icon {
  top: 1.1rem;
}

.form-input {
  width: 100%;
  padding: 0.85rem 1.1rem 0.85rem 2.85rem;
  font-family: var(--font-sans);
  font-size: 0.95rem;
  color: var(--text-main);
  background: var(--bg-input);
  border: 1px solid var(--border-subtle);
  border-radius: var(--border-radius-sm);
  outline: none;
  transition: all var(--transition-fast);
}

.form-input::placeholder {
  color: var(--text-dim);
}

.form-input:focus {
  border-color: var(--accent-indigo);
  box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.25);
  background: rgba(14, 23, 42, 0.95);
}

.form-input:focus + .input-icon,
.input-wrapper:focus-within .input-icon {
  color: var(--accent-cyan);
}

.form-select {
  appearance: none;
  background-image: url("data:image/svg+xml;charset=UTF-8,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%2394a3b8' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3e%3cpolyline points='6 9 12 15 18 9'%3e%3c/polyline%3e%3c/svg%3e");
  background-repeat: no-repeat;
  background-position: right 1rem center;
  background-size: 1.1em;
  cursor: pointer;
}

.form-textarea {
  resize: vertical;
  min-height: 130px;
  line-height: 1.6;
}

.textarea-bottom {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: 0.2rem;
}

.char-counter {
  font-size: 0.78rem;
  color: var(--text-dim);
  margin-left: auto;
}

/* Custom Checkbox */
.custom-checkbox-container {
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
  cursor: pointer;
  user-select: none;
  position: relative;
}

.custom-checkbox-container input {
  position: absolute;
  opacity: 0;
  cursor: pointer;
  height: 0;
  width: 0;
}

.checkmark {
  width: 20px;
  height: 20px;
  min-width: 20px;
  background-color: var(--bg-input);
  border: 1px solid var(--border-subtle);
  border-radius: 5px;
  display: inline-block;
  position: relative;
  margin-top: 2px;
  transition: all var(--transition-fast);
}

.custom-checkbox-container:hover .checkmark {
  border-color: var(--accent-cyan);
}

.custom-checkbox-container input:checked ~ .checkmark {
  background-color: var(--accent-indigo);
  border-color: var(--accent-indigo);
}

.checkmark::after {
  content: "";
  position: absolute;
  display: none;
  left: 6px;
  top: 2px;
  width: 5px;
  height: 10px;
  border: solid white;
  border-width: 0 2px 2px 0;
  transform: rotate(45deg);
}

.custom-checkbox-container input:checked ~ .checkmark::after {
  display: block;
}

.consent-text {
  font-size: 0.88rem;
  color: var(--text-muted);
  line-height: 1.5;
}

/* Error States */
.error-msg {
  display: none;
  font-size: 0.8rem;
  color: #f43f5e;
  margin-top: 0.25rem;
}

.form-group.has-error .error-msg,
.form-consent.has-error .error-msg {
  display: block;
}

.form-group.has-error .form-input {
  border-color: #f43f5e;
  box-shadow: 0 0 0 3px rgba(244, 63, 94, 0.2);
}

/* Submit Button & Spinner */
.btn-submit {
  width: 100%;
  padding: 0.95rem;
  font-size: 1.05rem;
  margin-top: 0.5rem;
  position: relative;
}

.btn-spinner {
  display: none;
}

.btn-submit.loading .btn-text {
  display: none;
}

.btn-submit.loading .btn-spinner {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
}

/* --------------------------------------------------------------------------
   12. Footer
   -------------------------------------------------------------------------- */
.site-footer {
  background: #05070c;
  border-top: 1px solid var(--border-subtle);
  padding: 4rem 0 2.5rem 0;
}

.footer-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 2rem;
  padding-bottom: 2.5rem;
  border-bottom: 1px solid var(--border-subtle);
}

.footer-brand {
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
}

.brand-title {
  font-family: var(--font-heading);
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--text-main);
}

.brand-subtitle {
  font-size: 0.85rem;
  color: var(--text-dim);
}

.footer-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 1.5rem;
}

.footer-nav a {
  font-size: 0.9rem;
  color: var(--text-muted);
  text-decoration: none;
  transition: color var(--transition-fast);
}

.footer-nav a:hover {
  color: var(--accent-cyan);
}

.footer-bottom {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 2rem;
}

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

.back-to-top-btn {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--border-subtle);
  color: var(--text-main);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.back-to-top-btn:hover {
  background: var(--gradient-primary);
  border-color: transparent;
  transform: translateY(-4px);
  box-shadow: 0 6px 20px rgba(99, 102, 241, 0.4);
}

/* --------------------------------------------------------------------------
   13. Toast Notification Component
   -------------------------------------------------------------------------- */
.toast-container {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  z-index: 1100;
  pointer-events: none;
}

.toast {
  pointer-events: auto;
  display: flex;
  align-items: center;
  gap: 0.85rem;
  min-width: 320px;
  max-width: 450px;
  padding: 1rem 1.25rem;
  background: rgba(15, 23, 42, 0.92);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: var(--border-radius-md);
  box-shadow: 0 15px 35px rgba(0, 0, 0, 0.6);
  color: var(--text-main);
  font-size: 0.92rem;
  transform: translateX(120%);
  opacity: 0;
  transition: all 0.35s cubic-bezier(0.16, 1, 0.3, 1);
}

.toast.show {
  transform: translateX(0);
  opacity: 1;
}

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

.toast.success .toast-icon {
  color: #10b981;
}

.toast.info .toast-icon {
  color: var(--accent-cyan);
}

.toast.error .toast-icon {
  color: #f43f5e;
}

.toast-message {
  flex: 1;
  line-height: 1.4;
}

.toast-close {
  background: transparent;
  border: none;
  color: var(--text-dim);
  cursor: pointer;
  font-size: 1.1rem;
  padding: 0.2rem;
  line-height: 1;
  transition: color var(--transition-fast);
}

.toast-close:hover {
  color: var(--text-main);
}

/* --------------------------------------------------------------------------
   14. BibTeX Modal
   -------------------------------------------------------------------------- */
.modal-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(3, 7, 18, 0.8);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1.5rem;
  z-index: 1200;
  opacity: 0;
  visibility: hidden;
  transition: all var(--transition-normal);
}

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

.modal-box {
  width: 100%;
  max-width: 650px;
  padding: 2rem;
  border: 1px solid rgba(255, 255, 255, 0.15);
  transform: scale(0.95);
  transition: transform var(--transition-normal);
}

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

.modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1.25rem;
}

.modal-title {
  font-family: var(--font-heading);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-main);
  display: flex;
  align-items: center;
  gap: 0.6rem;
}

.modal-title i {
  color: var(--accent-cyan);
}

.modal-close-btn {
  background: transparent;
  border: none;
  color: var(--text-muted);
  font-size: 1.8rem;
  cursor: pointer;
  line-height: 1;
  transition: color var(--transition-fast);
}

.modal-close-btn:hover {
  color: var(--text-main);
}

.modal-body {
  margin-bottom: 1.5rem;
}

.bibtex-code {
  display: block;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: #38bdf8;
  background: #060911;
  border: 1px solid var(--border-subtle);
  border-radius: var(--border-radius-sm);
  padding: 1.25rem;
  overflow-x: auto;
  white-space: pre;
  line-height: 1.6;
}

.modal-footer {
  display: flex;
  justify-content: flex-end;
  gap: 0.75rem;
}

/* --------------------------------------------------------------------------
   15. Scroll Animation Classes
   -------------------------------------------------------------------------- */
.reveal-on-scroll {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity 0.7s cubic-bezier(0.16, 1, 0.3, 1), transform 0.7s cubic-bezier(0.16, 1, 0.3, 1);
}

.reveal-on-scroll.revealed {
  opacity: 1;
  transform: translateY(0);
}

/* --------------------------------------------------------------------------
   16. Responsive Media Queries
   -------------------------------------------------------------------------- */
@media (max-width: 1024px) {
  .hero-container {
    grid-template-columns: 1fr;
    text-align: center;
    gap: 3rem;
  }

  .status-badge-wrapper {
    display: flex;
    justify-content: center;
  }

  .hero-description {
    margin-left: auto;
    margin-right: auto;
  }

  .hero-cta-group {
    justify-content: center;
  }

  .hero-stats-grid {
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
  }

  .hero-visual {
    order: -1;
  }

  .profile-card-wrapper {
    max-width: 360px;
  }

  .profile-img-container {
    height: 340px;
  }

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

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

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

@media (max-width: 768px) {
  :root {
    --header-height: 68px;
  }

  .desktop-nav,
  .header-cta {
    display: none;
  }

  .mobile-toggle-btn {
    display: flex;
  }

  .section-padding {
    padding-top: 4.5rem;
    padding-bottom: 4.5rem;
  }

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

  .form-row {
    grid-template-columns: 1fr;
  }

  .timeline-line {
    left: 20px;
  }

  .timeline-marker {
    left: 2px;
    width: 36px;
    height: 36px;
  }

  .timeline-item {
    padding-left: 54px;
  }

  .timeline-header {
    flex-direction: column;
    align-items: flex-start;
  }

  .floating-tech-badge {
    display: none;
  }

  .footer-top,
  .footer-bottom {
    flex-direction: column;
    align-items: center;
    text-align: center;
    gap: 1.5rem;
  }

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

  .toast-container {
    left: 1rem;
    right: 1rem;
    bottom: 1rem;
  }

  .toast {
    min-width: 100%;
  }
}

@media (max-width: 480px) {
  .hero-title {
    font-size: 2.1rem;
  }

  .hero-cta-group .btn {
    width: 100%;
  }

  .about-card,
  .timeline-content,
  .pub-card,
  .award-card,
  .contact-info-card,
  .contact-form-wrapper {
    padding: 1.5rem;
  }

  .pub-card-header {
    flex-direction: column;
    align-items: flex-start;
  }
}