/* ================================================================
   MAIN.CSS — Futuristic AI/ML/Robotics Portfolio
   Arijit De | 2025
   ================================================================ */

/* ----------------------------------------------------------------
   1. CUSTOM PROPERTIES
   ---------------------------------------------------------------- */
:root {
  --bg-deep:        #050A13;
  --bg-section:     #080D19;
  --bg-card:        rgba(255, 255, 255, 0.03);
  --bg-card-hover:  rgba(0, 212, 255, 0.06);
  --accent-cyan:    #00D4FF;
  --accent-purple:  #7B2FBE;
  --accent-green:   #00FF88;
  --accent-orange:  #FF6B35;
  --text-primary:   #E8EDF5;
  --text-secondary: #8892A4;
  --text-muted:     #4A5568;
  --border-glow:    rgba(0, 212, 255, 0.2);
  --border-subtle:  rgba(255, 255, 255, 0.06);
  --glow-cyan:      0 0 20px rgba(0, 212, 255, 0.4);
  --glow-purple:    0 0 20px rgba(123, 47, 190, 0.4);
  --nav-height:     70px;
  --transition:     0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --radius-sm:      6px;
  --radius-md:      12px;
  --radius-lg:      20px;
}

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

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

body {
  background-color: var(--bg-deep);
  color: var(--text-primary);
  font-family: 'Inter', sans-serif;
  line-height: 1.7;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--accent-cyan);
  text-decoration: none;
  transition: color var(--transition);
}
a:hover { color: #fff; }

h1, h2, h3, h4, h5 {
  font-family: 'Orbitron', sans-serif;
  font-weight: 700;
  letter-spacing: 0.05em;
  line-height: 1.2;
}

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

/* Custom scrollbar */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: var(--bg-deep); }
::-webkit-scrollbar-thumb {
  background: var(--accent-cyan);
  border-radius: 3px;
}

/* Section base */
section {
  padding: 100px 0;
  position: relative;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

/* Section heading */
.section-title {
  text-align: center;
  margin-bottom: 64px;
}
.section-title h2 {
  font-size: clamp(1.6rem, 3vw, 2.4rem);
  color: var(--text-primary);
  position: relative;
  display: inline-block;
  padding-bottom: 16px;
}
.section-title h2::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 60px;
  height: 3px;
  background: linear-gradient(90deg, var(--accent-cyan), var(--accent-purple));
  border-radius: 2px;
}
.section-title p {
  color: var(--text-secondary);
  font-size: 1rem;
  margin-top: 12px;
}

/* ----------------------------------------------------------------
   3. NAVBAR
   ---------------------------------------------------------------- */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  height: var(--nav-height);
  display: flex;
  align-items: center;
  background: rgba(5, 10, 19, 0.7);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border-glow);
  transition: background var(--transition), box-shadow var(--transition);
}
.navbar.scrolled {
  background: rgba(5, 10, 19, 0.95);
  box-shadow: 0 4px 30px rgba(0, 212, 255, 0.08);
}

.navbar .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
}

.navbar-brand {
  font-family: 'Orbitron', sans-serif;
  font-size: 1.3rem;
  font-weight: 900;
  color: var(--accent-cyan) !important;
  letter-spacing: 0.15em;
  text-shadow: 0 0 20px rgba(0, 212, 255, 0.5);
  text-decoration: none;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 8px;
  list-style: none;
}

.nav-links a {
  color: var(--text-secondary);
  font-size: 0.82rem;
  font-weight: 500;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  padding: 8px 16px;
  border-radius: var(--radius-sm);
  transition: color var(--transition), background var(--transition);
  text-decoration: none;
}
.nav-links a:hover,
.nav-links a.active {
  color: var(--accent-cyan);
  background: rgba(0, 212, 255, 0.08);
}

/* Hamburger */
.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  padding: 4px;
  background: none;
  border: none;
}
.nav-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--accent-cyan);
  border-radius: 2px;
  transition: transform var(--transition), opacity var(--transition);
}
.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); }

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

#neural-canvas {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  z-index: 0;
}

.hero-content {
  position: relative;
  z-index: 2;
  text-align: center;
  padding: 40px 24px;
  max-width: 800px;
}

/* Profile photo */
.profile-ring {
  position: relative;
  display: inline-block;
  margin-bottom: 32px;
}
.profile-ring::before {
  content: '';
  position: absolute;
  inset: -6px;
  border-radius: 50%;
  background: conic-gradient(var(--accent-cyan), var(--accent-purple), var(--accent-cyan));
  animation: spin 4s linear infinite;
  z-index: -1;
}
.profile-ring::after {
  content: '';
  position: absolute;
  inset: -12px;
  border-radius: 50%;
  background: transparent;
  border: 1px solid rgba(0, 212, 255, 0.2);
  animation: pulse-ring 2s ease-in-out infinite;
}
@keyframes spin {
  to { transform: rotate(360deg); }
}
@keyframes pulse-ring {
  0%, 100% { transform: scale(1); opacity: 1; }
  50% { transform: scale(1.05); opacity: 0.5; }
}

.profile-photo {
  width: 160px;
  height: 160px;
  border-radius: 50%;
  object-fit: cover;
  border: 4px solid var(--bg-deep);
  display: block;
}

/* Hero text */
.hero-name {
  font-size: clamp(2.2rem, 5vw, 3.8rem);
  color: #fff;
  text-shadow: 0 0 40px rgba(0, 212, 255, 0.3);
  margin-bottom: 16px;
}
.hero-name span {
  color: var(--accent-cyan);
}

.hero-tagline {
  font-size: 0.8rem;
  letter-spacing: 0.3em;
  text-transform: uppercase;
  color: var(--accent-purple);
  margin-bottom: 24px;
  font-family: 'Orbitron', sans-serif;
}

.hero-typed-wrap {
  font-size: clamp(1.1rem, 2.5vw, 1.5rem);
  color: var(--text-secondary);
  min-height: 2.5rem;
  margin-bottom: 40px;
}
.hero-typed-wrap #typed {
  color: var(--accent-cyan);
  font-weight: 600;
}
.typed-cursor {
  color: var(--accent-cyan);
  font-size: 1.4em;
  animation: blink 0.7s infinite;
}
@keyframes blink {
  0%, 100% { opacity: 1; }
  50% { opacity: 0; }
}

/* Hero CTA buttons */
.hero-cta {
  display: flex;
  gap: 16px;
  justify-content: center;
  flex-wrap: wrap;
}

/* Scroll indicator */
.scroll-indicator {
  position: absolute;
  bottom: 32px;
  left: 50%;
  transform: translateX(-50%);
  z-index: 2;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  color: var(--text-muted);
  font-size: 0.7rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
}
.scroll-arrow {
  width: 20px;
  height: 20px;
  border-right: 2px solid var(--accent-cyan);
  border-bottom: 2px solid var(--accent-cyan);
  transform: rotate(45deg);
  animation: scroll-bounce 1.5s ease-in-out infinite;
}
@keyframes scroll-bounce {
  0%, 100% { transform: rotate(45deg) translateY(0); opacity: 1; }
  50% { transform: rotate(45deg) translateY(6px); opacity: 0.4; }
}

/* ----------------------------------------------------------------
   5. BUTTONS
   ---------------------------------------------------------------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 28px;
  border-radius: var(--radius-sm);
  font-size: 0.85rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  cursor: pointer;
  transition: all var(--transition);
  border: none;
  text-decoration: none;
}

.btn-primary {
  background: var(--accent-cyan);
  color: var(--bg-deep);
}
.btn-primary:hover {
  background: #fff;
  color: var(--bg-deep);
  box-shadow: 0 8px 32px rgba(0, 212, 255, 0.4);
  transform: translateY(-2px);
}

.btn-outline {
  background: transparent;
  color: var(--accent-cyan);
  border: 1px solid var(--accent-cyan);
}
.btn-outline:hover {
  background: rgba(0, 212, 255, 0.1);
  color: var(--accent-cyan);
  box-shadow: var(--glow-cyan);
  transform: translateY(-2px);
}

.btn-ghost {
  background: transparent;
  color: var(--text-secondary);
  border: 1px solid var(--border-subtle);
}
.btn-ghost:hover {
  color: var(--text-primary);
  border-color: var(--border-glow);
  background: var(--bg-card);
}

/* Breathing animation (PhD thesis button) */
.btn-breathing {
  animation: breathing 2.5s ease-in-out infinite;
  background: linear-gradient(135deg, var(--accent-purple), #5b1fa0);
  color: #fff;
}
.btn-breathing:hover {
  background: linear-gradient(135deg, #9b4fe0, var(--accent-purple));
  color: #fff;
  animation-play-state: paused;
  transform: translateY(-2px);
  box-shadow: var(--glow-purple);
}
@keyframes breathing {
  0%, 100% { transform: scale(1); box-shadow: 0 0 0 rgba(123, 47, 190, 0); }
  50% { transform: scale(1.04); box-shadow: 0 0 20px rgba(123, 47, 190, 0.5); }
}

/* ----------------------------------------------------------------
   6. ABOUT SECTION
   ---------------------------------------------------------------- */
.about-section {
  background: var(--bg-section);
}

.about-grid {
  display: grid;
  grid-template-columns: 3fr 2fr;
  gap: 48px;
  align-items: start;
}

.about-text p {
  color: var(--text-secondary);
  margin-bottom: 20px;
  font-size: 0.95rem;
  line-height: 1.8;
}
.about-text a {
  color: var(--accent-cyan);
  border-bottom: 1px solid transparent;
  transition: border-color var(--transition);
}
.about-text a:hover { border-color: var(--accent-cyan); }

.about-cta {
  margin-top: 32px;
}

/* PhD card */
.phd-card {
  background: var(--bg-card);
  border: 1px solid var(--border-glow);
  border-radius: var(--radius-md);
  padding: 28px;
  position: relative;
  overflow: hidden;
}
.phd-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--accent-cyan), var(--accent-purple));
}
.phd-card h4 {
  font-size: 0.7rem;
  letter-spacing: 0.25em;
  text-transform: uppercase;
  color: var(--accent-cyan);
  margin-bottom: 12px;
}
.phd-card h3 {
  font-size: 1rem;
  color: var(--text-primary);
  line-height: 1.5;
  margin-bottom: 16px;
  font-family: 'Inter', sans-serif;
  font-weight: 600;
}
.phd-card p {
  font-size: 0.85rem;
  color: var(--text-secondary);
  line-height: 1.7;
}
.phd-card a {
  color: var(--accent-cyan);
}
.phd-card .phd-cta {
  margin-top: 20px;
}
.phd-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: rgba(0, 255, 136, 0.1);
  border: 1px solid rgba(0, 255, 136, 0.3);
  color: var(--accent-green);
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  padding: 4px 12px;
  border-radius: 100px;
  margin-bottom: 16px;
}

/* ----------------------------------------------------------------
   7. SKILLS SECTION
   ---------------------------------------------------------------- */
.skills-section {
  background: var(--bg-deep);
}

/* Category tabs */
.skills-tabs {
  display: flex;
  justify-content: center;
  gap: 8px;
  margin-bottom: 48px;
  flex-wrap: wrap;
}

.skills-tab {
  padding: 10px 24px;
  border-radius: 100px;
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  cursor: pointer;
  border: 1px solid var(--border-subtle);
  background: transparent;
  color: var(--text-secondary);
  transition: all var(--transition);
  font-family: 'Orbitron', sans-serif;
}
.skills-tab:hover {
  color: var(--accent-cyan);
  border-color: var(--border-glow);
}
.skills-tab.active {
  background: rgba(0, 212, 255, 0.1);
  border-color: var(--accent-cyan);
  color: var(--accent-cyan);
  box-shadow: 0 0 16px rgba(0, 212, 255, 0.2);
}

/* Skills panel */
.skills-panel {
  display: none;
}
.skills-panel.active {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(110px, 1fr));
  gap: 16px;
  animation: fadeIn 0.3s ease;
}
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(10px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* Skill card */
.skill-card {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
  padding: 20px 12px;
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  cursor: default;
  transition: all var(--transition);
  text-align: center;
}
.skill-card:hover {
  background: var(--bg-card-hover);
  border-color: var(--border-glow);
  transform: translateY(-4px);
  box-shadow: var(--glow-cyan);
}
.skill-card img,
.skill-card svg {
  width: 44px;
  height: 44px;
  object-fit: contain;
  filter: brightness(0.9);
  transition: filter var(--transition), transform var(--transition);
}
.skill-card:hover img,
.skill-card:hover svg {
  filter: brightness(1.2) drop-shadow(0 0 8px rgba(0, 212, 255, 0.5));
  transform: scale(1.1);
}
.skill-card span {
  font-size: 0.72rem;
  color: var(--text-secondary);
  font-weight: 500;
  letter-spacing: 0.05em;
}

/* ----------------------------------------------------------------
   8. FEATURED WORK CTA SECTION
   ---------------------------------------------------------------- */
.work-section {
  background: var(--bg-section);
  padding: 80px 0;
}

.work-section .section-title {
  margin-bottom: 48px;
}

.work-cards {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 32px;
}

.work-card {
  position: relative;
  padding: 48px 40px;
  border-radius: var(--radius-lg);
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  overflow: hidden;
  transition: all var(--transition);
  text-decoration: none;
  display: flex;
  flex-direction: column;
  gap: 20px;
}
.work-card::before {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: var(--radius-lg);
  padding: 1px;
  background: linear-gradient(135deg, transparent, transparent);
  -webkit-mask: linear-gradient(#fff 0 0) content-box, linear-gradient(#fff 0 0);
  -webkit-mask-composite: xor;
  mask-composite: exclude;
  transition: background var(--transition);
  pointer-events: none;
}
.work-card:hover::before {
  background: linear-gradient(135deg, var(--accent-cyan), var(--accent-purple));
}
.work-card:hover {
  transform: translateY(-6px);
  background: rgba(255, 255, 255, 0.05);
  border-color: transparent;
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.4);
}

.work-card-icon {
  font-size: 2.4rem;
  line-height: 1;
}
.work-card.projects .work-card-icon { color: var(--accent-cyan); }
.work-card.publications .work-card-icon { color: var(--accent-purple); }

.work-card-label {
  font-size: 0.65rem;
  letter-spacing: 0.3em;
  text-transform: uppercase;
  font-family: 'Orbitron', sans-serif;
}
.work-card.projects .work-card-label { color: var(--accent-cyan); }
.work-card.publications .work-card-label { color: var(--accent-purple); }

.work-card h3 {
  font-size: clamp(1.6rem, 3vw, 2.2rem);
  color: var(--text-primary);
  font-family: 'Orbitron', sans-serif;
}

.work-card p {
  color: var(--text-secondary);
  font-size: 0.9rem;
  line-height: 1.7;
  flex: 1;
}

.work-card-arrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-size: 0.82rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  transition: gap var(--transition);
}
.work-card.projects .work-card-arrow { color: var(--accent-cyan); }
.work-card.publications .work-card-arrow { color: var(--accent-purple); }
.work-card:hover .work-card-arrow { gap: 18px; }

.work-card-bg-number {
  position: absolute;
  bottom: -10px;
  right: 20px;
  font-family: 'Orbitron', sans-serif;
  font-size: 8rem;
  font-weight: 900;
  line-height: 1;
  opacity: 0.04;
  pointer-events: none;
  user-select: none;
  color: var(--text-primary);
}

/* ----------------------------------------------------------------
   9. FOOTER
   ---------------------------------------------------------------- */
.site-footer {
  background: #020508;
  padding: 60px 0 0;
  border-top: 1px solid var(--border-subtle);
}

.footer-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 40px;
  padding-bottom: 48px;
}

.footer-col h4 {
  font-size: 0.68rem;
  letter-spacing: 0.25em;
  text-transform: uppercase;
  color: var(--accent-cyan);
  margin-bottom: 20px;
  font-family: 'Orbitron', sans-serif;
}

.footer-col p {
  color: var(--text-secondary);
  font-size: 0.88rem;
}

.social-links {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

.social-link {
  width: 40px;
  height: 40px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-subtle);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-secondary);
  font-size: 1rem;
  transition: all var(--transition);
  text-decoration: none;
}
.social-link:hover {
  color: var(--accent-cyan);
  border-color: var(--border-glow);
  background: rgba(0, 212, 255, 0.08);
  box-shadow: var(--glow-cyan);
  transform: translateY(-2px);
}
.social-link svg {
  width: 16px;
  height: 16px;
  fill: currentColor;
}

.footer-blog-link {
  color: var(--text-secondary);
  font-size: 0.88rem;
  transition: color var(--transition);
  display: inline-flex;
  align-items: center;
  gap: 8px;
  text-decoration: none;
}
.footer-blog-link:hover { color: var(--accent-cyan); }

.footer-bottom {
  border-top: 1px solid var(--border-subtle);
  padding: 20px 0;
  text-align: center;
}
.footer-bottom p {
  font-size: 0.78rem;
  color: var(--text-muted);
}

/* ----------------------------------------------------------------
   10. PAGE HERO (projects / publications)
   ---------------------------------------------------------------- */
.page-hero {
  padding-top: calc(var(--nav-height) + 60px);
  padding-bottom: 60px;
  text-align: center;
  background: var(--bg-section);
  position: relative;
  overflow: hidden;
}
.page-hero::after {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse at 50% 0%, rgba(0,212,255,0.06) 0%, transparent 70%);
  pointer-events: none;
}
.page-hero h1 {
  font-size: clamp(2rem, 5vw, 3.5rem);
  color: var(--text-primary);
  margin-bottom: 16px;
}
.page-hero h1 span { color: var(--accent-cyan); }
.page-hero p {
  color: var(--text-secondary);
  font-size: 1rem;
  max-width: 600px;
  margin: 0 auto;
}

/* ----------------------------------------------------------------
   11. GIF BANNER (Projects page)
   ---------------------------------------------------------------- */
.gif-banner {
  position: relative;
  margin: 0 0 80px;
  border-radius: var(--radius-lg);
  overflow: hidden;
  max-height: 360px;
  border: 1px solid var(--border-glow);
}
.gif-banner img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}
.gif-banner-overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(
    to right,
    rgba(5,10,19,0.85) 0%,
    rgba(5,10,19,0.3) 50%,
    rgba(5,10,19,0.1) 100%
  );
  display: flex;
  align-items: center;
  padding: 40px;
}
.gif-banner-text h2 {
  font-size: clamp(1.4rem, 3vw, 2.2rem);
  color: #fff;
  margin-bottom: 8px;
}
.gif-banner-text p {
  color: var(--text-secondary);
  font-size: 0.9rem;
}

/* ----------------------------------------------------------------
   12. PROJECT CARDS
   ---------------------------------------------------------------- */
.projects-section {
  background: var(--bg-deep);
  padding-top: 0;
}

.projects-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}

.project-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 32px;
  transition: all var(--transition);
  display: flex;
  flex-direction: column;
  gap: 16px;
  position: relative;
  overflow: hidden;
}
.project-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--accent-cyan), var(--accent-purple));
  transform: scaleX(0);
  transition: transform var(--transition);
  transform-origin: left;
}
.project-card:hover::before { transform: scaleX(1); }
.project-card:hover {
  background: var(--bg-card-hover);
  border-color: var(--border-glow);
  transform: translateY(-4px);
  box-shadow: 0 16px 48px rgba(0, 0, 0, 0.3);
}

.project-card h3 {
  font-size: 1rem;
  color: var(--text-primary);
  font-family: 'Inter', sans-serif;
  font-weight: 700;
  line-height: 1.4;
}

.project-card p {
  color: var(--text-secondary);
  font-size: 0.88rem;
  line-height: 1.7;
  flex: 1;
}
.project-card a.pub-link {
  color: var(--accent-cyan);
  border-bottom: 1px solid transparent;
  transition: border-color var(--transition);
}
.project-card a.pub-link:hover { border-color: var(--accent-cyan); }

.project-links {
  display: flex;
  gap: 12px;
  align-items: center;
  margin-top: 8px;
}

.github-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 18px;
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--text-secondary);
  letter-spacing: 0.05em;
  transition: all var(--transition);
  text-decoration: none;
}
.github-btn:hover {
  color: var(--accent-cyan);
  border-color: var(--border-glow);
  background: rgba(0, 212, 255, 0.06);
}
.github-btn i { font-size: 1.1em; }

/* ----------------------------------------------------------------
   13. PUBLICATIONS PAGE
   ---------------------------------------------------------------- */
.publications-section {
  background: var(--bg-deep);
  padding-top: 0;
}

.pub-timeline {
  position: relative;
  max-width: 860px;
  margin: 0 auto;
  padding-left: 20px;
}
.pub-timeline::before {
  content: '';
  position: absolute;
  top: 0;
  bottom: 0;
  left: 0;
  width: 1px;
  background: linear-gradient(to bottom, var(--accent-cyan), var(--accent-purple), transparent);
}

.pub-item {
  display: flex;
  gap: 28px;
  margin-bottom: 48px;
  position: relative;
}

.pub-badge {
  flex-shrink: 0;
  width: 56px;
  height: 56px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: 'Orbitron', sans-serif;
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  z-index: 1;
  box-shadow: 0 0 0 4px var(--bg-deep);
}
.pub-badge.journal {
  background: rgba(0, 212, 255, 0.1);
  border: 2px solid var(--accent-cyan);
  color: var(--accent-cyan);
  box-shadow: 0 0 0 4px var(--bg-deep), var(--glow-cyan);
}
.pub-badge.conference {
  background: rgba(123, 47, 190, 0.1);
  border: 2px solid var(--accent-purple);
  color: var(--accent-purple);
  box-shadow: 0 0 0 4px var(--bg-deep), var(--glow-purple);
}

.pub-content {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 24px 28px;
  flex: 1;
  transition: all var(--transition);
}
.pub-content:hover {
  border-color: var(--border-glow);
  background: var(--bg-card-hover);
}

.pub-content h3 {
  font-size: 0.98rem;
  color: var(--text-primary);
  font-family: 'Inter', sans-serif;
  font-weight: 700;
  line-height: 1.5;
  margin-bottom: 10px;
}

.pub-content .pub-citation {
  font-size: 0.82rem;
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: 12px;
}
.pub-content .pub-citation a {
  color: var(--accent-cyan);
  font-size: 0.8rem;
}

.pub-actions {
  display: flex;
  gap: 10px;
  align-items: center;
  flex-wrap: wrap;
}

.pub-pdf-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 16px;
  border-radius: var(--radius-sm);
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  text-decoration: none;
  transition: all var(--transition);
}
.pub-pdf-btn.journal {
  border: 1px solid rgba(0, 212, 255, 0.4);
  color: var(--accent-cyan);
  background: rgba(0, 212, 255, 0.05);
}
.pub-pdf-btn.journal:hover {
  background: rgba(0, 212, 255, 0.15);
  box-shadow: var(--glow-cyan);
}
.pub-pdf-btn.conference {
  border: 1px solid rgba(123, 47, 190, 0.4);
  color: var(--accent-purple);
  background: rgba(123, 47, 190, 0.05);
}
.pub-pdf-btn.conference:hover {
  background: rgba(123, 47, 190, 0.15);
  box-shadow: var(--glow-purple);
}

/* ----------------------------------------------------------------
   14. BACK TO TOP
   ---------------------------------------------------------------- */
.back-to-top {
  position: fixed;
  bottom: 32px;
  right: 32px;
  width: 44px;
  height: 44px;
  background: rgba(0, 212, 255, 0.1);
  border: 1px solid var(--border-glow);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--accent-cyan);
  font-size: 1.1rem;
  cursor: pointer;
  opacity: 0;
  pointer-events: none;
  transition: all var(--transition);
  z-index: 999;
  text-decoration: none;
}
.back-to-top.visible {
  opacity: 1;
  pointer-events: auto;
}
.back-to-top:hover {
  background: var(--accent-cyan);
  color: var(--bg-deep);
  box-shadow: var(--glow-cyan);
}

/* ----------------------------------------------------------------
   15. AOS & GSAP INTEGRATION
   ---------------------------------------------------------------- */
[data-aos] { transition-timing-function: cubic-bezier(0.4, 0, 0.2, 1); }

/* ----------------------------------------------------------------
   16. RESPONSIVE
   ---------------------------------------------------------------- */
@media (max-width: 1024px) {
  .about-grid { grid-template-columns: 1fr; }
  .work-cards { grid-template-columns: 1fr; gap: 20px; }
}

@media (max-width: 768px) {
  section { padding: 72px 0; }

  .nav-links {
    display: none;
    position: absolute;
    top: var(--nav-height);
    left: 0;
    right: 0;
    flex-direction: column;
    background: rgba(5, 10, 19, 0.98);
    backdrop-filter: blur(20px);
    padding: 20px;
    border-bottom: 1px solid var(--border-glow);
    gap: 4px;
  }
  .nav-links.open { display: flex; }
  .nav-links a {
    padding: 12px 16px;
    width: 100%;
  }
  .nav-toggle { display: flex; }

  .profile-photo { width: 130px; height: 130px; }
  .hero-cta { flex-direction: column; align-items: center; }

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

  .footer-grid { grid-template-columns: 1fr; gap: 32px; }

  .pub-timeline::before { left: 0; }
  .pub-badge { width: 44px; height: 44px; font-size: 0.65rem; }

  .skills-panel.active {
    grid-template-columns: repeat(auto-fill, minmax(90px, 1fr));
    gap: 12px;
  }

  .gif-banner-overlay { padding: 24px; }

  .work-card { padding: 32px 24px; }
}

@media (max-width: 480px) {
  .skills-panel.active {
    grid-template-columns: repeat(3, 1fr);
  }
  .work-card h3 { font-size: 1.4rem; }
  .pub-item { gap: 16px; }
  .pub-content { padding: 18px; }
}

/* ----------------------------------------------------------------
   17. UTILITY
   ---------------------------------------------------------------- */
.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
}

.text-cyan    { color: var(--accent-cyan); }
.text-purple  { color: var(--accent-purple); }
.text-muted   { color: var(--text-muted); }