/* ============================================================
   GYANENDRA SHARMA, PhD — PORTFOLIO STYLESHEET
   Senior HMI & UX Researcher
   ============================================================ */

/* ============================
   1. DESIGN TOKENS / VARIABLES
   ============================ */
:root {
  /* Background Scale */
  --bg-950: #04091a;
  --bg-900: #060e24;
  --bg-800: #0b1530;
  --bg-700: #0f1e42;
  --bg-600: #162654;

  /* Card / Glass */
  --card-bg: rgba(11, 21, 48, 0.7);
  --card-border: rgba(79, 126, 240, 0.13);
  --glass-bg: rgba(15, 30, 66, 0.55);

  /* Accent Palette */
  --blue: #4f7ef0;
  --blue-light: #7aa3f5;
  --cyan: #22d3ee;
  --gold: #f59e0b;
  --green: #34d399;
  --purple: #a78bfa;

  /* Text */
  --text-100: #f1f5f9;
  --text-200: #e2e8f0;
  --text-300: #cbd5e1;
  --text-400: #94a3b8;
  --text-500: #64748b;
  --text-600: #475569;

  /* Gradients */
  --grad-primary: linear-gradient(135deg, #4f7ef0 0%, #22d3ee 100%);
  --grad-gold: linear-gradient(135deg, #f59e0b 0%, #fcd34d 100%);
  --grad-text: linear-gradient(135deg, #4f7ef0 30%, #22d3ee 100%);

  /* Shadows */
  --shadow-sm: 0 2px 10px rgba(0,0,0,0.35);
  --shadow-md: 0 6px 24px rgba(0,0,0,0.45);
  --shadow-lg: 0 12px 48px rgba(0,0,0,0.6);
  --shadow-glow: 0 0 30px rgba(79, 126, 240, 0.25);
  --shadow-glow-sm: 0 0 14px rgba(79, 126, 240, 0.2);

  /* Typography */
  --font-serif: 'Playfair Display', 'Georgia', serif;
  --font-sans: 'Inter', system-ui, -apple-system, sans-serif;

  /* Spacing & Layout */
  --container: 1200px;
  --section-y: 6rem;
  --radius-xs: 4px;
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --radius-xl: 28px;
  --radius-pill: 999px;

  /* Transitions */
  --ease: cubic-bezier(0.4, 0, 0.2, 1);
  --trans: all 0.3s var(--ease);
  --trans-slow: all 0.6s var(--ease);
}


/* ============================
   2. RESET & BASE
   ============================ */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; font-size: 16px; }
body {
  font-family: var(--font-sans);
  background: var(--bg-950);
  color: var(--text-100);
  line-height: 1.7;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}
img { max-width: 100%; height: auto; display: block; }
a { text-decoration: none; color: inherit; }
ul { list-style: none; }
button { cursor: pointer; border: none; background: none; font-family: inherit; }

/* Scrollbar */
::-webkit-scrollbar { width: 5px; }
::-webkit-scrollbar-track { background: var(--bg-950); }
::-webkit-scrollbar-thumb { background: var(--bg-600); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--blue); }


/* ============================
   3. TYPOGRAPHY
   ============================ */
.label {
  display: block;
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--cyan);
  margin-bottom: 0.75rem;
}

.section-title {
  font-family: var(--font-serif);
  font-size: clamp(1.8rem, 4vw, 2.6rem);
  font-weight: 700;
  line-height: 1.2;
  color: var(--text-100);
  margin-bottom: 1rem;
}
.section-title span {
  background: var(--grad-text);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.section-sub {
  font-size: 0.975rem;
  color: var(--text-400);
  max-width: 580px;
  line-height: 1.75;
  margin-bottom: 2.75rem;
}


/* ============================
   4. LAYOUT
   ============================ */
.container {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 2rem;
}
section { padding: var(--section-y) 0; }
section:nth-child(even) { background: var(--bg-800); }


/* ============================
   5. BUTTONS
   ============================ */
.btn-primary {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.875rem 2rem;
  background: var(--grad-primary);
  color: white;
  border-radius: var(--radius-pill);
  font-weight: 600;
  font-size: 0.9rem;
  letter-spacing: 0.02em;
  transition: var(--trans);
  box-shadow: 0 4px 18px rgba(79,126,240,0.35);
  white-space: nowrap;
}
.btn-primary:hover {
  transform: translateY(-3px);
  box-shadow: 0 10px 32px rgba(79,126,240,0.5);
}
.btn-secondary {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.875rem 2rem;
  background: rgba(255,255,255,0.04);
  color: var(--text-200);
  border: 1px solid rgba(255,255,255,0.15);
  border-radius: var(--radius-pill);
  font-weight: 500;
  font-size: 0.9rem;
  transition: var(--trans);
  white-space: nowrap;
}
.btn-secondary:hover {
  background: rgba(255,255,255,0.08);
  border-color: rgba(255,255,255,0.3);
  transform: translateY(-3px);
}


/* ============================
   6. SCROLL ANIMATIONS
   ============================ */
.reveal, .reveal-left, .reveal-right {
  opacity: 0;
  transition: opacity 0.75s var(--ease), transform 0.75s var(--ease);
}
.reveal { transform: translateY(32px); }
.reveal-left { transform: translateX(-40px); }
.reveal-right { transform: translateX(40px); }
.reveal.visible,
.reveal-left.visible,
.reveal-right.visible {
  opacity: 1;
  transform: none;
}
/* Stagger delay helper classes */
.delay-1 { transition-delay: 0.1s !important; }
.delay-2 { transition-delay: 0.2s !important; }
.delay-3 { transition-delay: 0.3s !important; }
.delay-4 { transition-delay: 0.4s !important; }
.delay-5 { transition-delay: 0.5s !important; }


/* ============================
   7. NAVBAR
   ============================ */
#navbar {
  position: fixed;
  top: 0; left: 0;
  width: 100%;
  z-index: 1000;
  padding: 1.375rem 0;
  transition: var(--trans);
}
#navbar.scrolled {
  background: rgba(4, 9, 26, 0.88);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  padding: 0.9rem 0;
  border-bottom: 1px solid var(--card-border);
  box-shadow: var(--shadow-md);
}
.nav-container {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 2rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.nav-logo {
  font-family: var(--font-serif);
  font-size: 1.45rem;
  font-weight: 700;
  background: var(--grad-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  letter-spacing: 0.04em;
}
.nav-links {
  display: flex;
  align-items: center;
  gap: 0.125rem;
}
.nav-links a {
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--text-400);
  padding: 0.45rem 0.875rem;
  border-radius: var(--radius-sm);
  transition: var(--trans);
  position: relative;
}
.nav-links a::after {
  content: '';
  position: absolute;
  bottom: 0; left: 50%;
  width: 0; height: 2px;
  background: var(--grad-primary);
  transform: translateX(-50%);
  transition: width 0.3s var(--ease);
  border-radius: 1px;
}
.nav-links a:hover, .nav-links a.active { color: var(--text-100); }
.nav-links a:hover::after, .nav-links a.active::after { width: 65%; }
.btn-nav-resume {
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--blue);
  border: 1px solid var(--blue);
  padding: 0.5rem 1.1rem;
  border-radius: var(--radius-pill);
  letter-spacing: 0.03em;
  transition: var(--trans);
}
.btn-nav-resume:hover {
  background: var(--blue);
  color: white;
  box-shadow: 0 4px 14px rgba(79,126,240,0.4);
}
.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  padding: 4px;
}
.nav-toggle span {
  display: block;
  width: 22px; height: 2px;
  background: var(--text-100);
  border-radius: 2px;
  transition: var(--trans);
}
.nav-toggle.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle.open span:nth-child(2) { opacity: 0; transform: scaleX(0); }
.nav-toggle.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* Mobile nav drawer */
.mobile-nav {
  position: fixed;
  top: 0; right: -100%;
  width: min(290px, 80vw);
  height: 100vh;
  background: var(--bg-700);
  z-index: 999;
  padding: 5.5rem 2rem 2rem;
  transition: right 0.4s var(--ease);
  border-left: 1px solid var(--card-border);
  display: flex;
  flex-direction: column;
  gap: 0.375rem;
  box-shadow: -10px 0 40px rgba(0,0,0,0.5);
}
.mobile-nav.open { right: 0; }
.mobile-nav a {
  display: block;
  padding: 0.8rem 1rem;
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--text-400);
  border-radius: var(--radius-sm);
  transition: var(--trans);
}
.mobile-nav a:hover { color: var(--text-100); background: rgba(79,126,240,0.1); }
.btn-mobile-resume {
  margin-top: 1.25rem;
  display: block;
  padding: 0.875rem;
  background: var(--grad-primary);
  color: white !important;
  text-align: center;
  border-radius: var(--radius-md);
  font-weight: 700;
  font-size: 0.875rem;
  box-shadow: 0 4px 14px rgba(79,126,240,0.3);
}
.nav-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.55);
  z-index: 998;
  opacity: 0;
  visibility: hidden;
  transition: var(--trans);
}
.nav-overlay.visible { opacity: 1; visibility: visible; }


/* ============================
   8. HERO
   ============================ */
#hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  position: relative;
  overflow: hidden;
  padding: 7rem 0 5rem;
  background: var(--bg-950);
}
#particles-canvas {
  position: absolute;
  inset: 0;
  width: 100%; height: 100%;
  z-index: 0;
}
.hero-glow {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 70% 70% at 20% 50%, rgba(79,126,240,0.07) 0%, transparent 65%),
    radial-gradient(ellipse 50% 70% at 75% 25%, rgba(34,211,238,0.05) 0%, transparent 65%);
  z-index: 0;
}
.hero-layout {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 4rem;
  align-items: center;
}

/* Hero text */
.hero-text { display: flex; flex-direction: column; gap: 1.75rem; }
.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.375rem 1rem;
  background: rgba(79,126,240,0.1);
  border: 1px solid rgba(79,126,240,0.3);
  border-radius: var(--radius-pill);
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--cyan);
  width: fit-content;
}
.badge-dot {
  width: 7px; height: 7px;
  border-radius: 50%;
  background: var(--green);
  box-shadow: 0 0 8px var(--green);
  animation: pulseDot 2s ease-in-out infinite;
}
@keyframes pulseDot {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.5; transform: scale(0.8); }
}
.hero-name {
  font-family: var(--font-serif);
  font-size: clamp(2.8rem, 6vw, 4.2rem);
  font-weight: 700;
  line-height: 1.08;
  color: var(--text-100);
}
.hero-name .first { display: block; }
.hero-name .last {
  display: block;
  background: var(--grad-text);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.hero-name .phd {
  font-size: 0.38em;
  font-family: var(--font-sans);
  font-weight: 400;
  color: var(--text-400);
  -webkit-text-fill-color: var(--text-400);
  vertical-align: super;
  margin-left: 0.35em;
  letter-spacing: 0.06em;
}
.hero-subtitle {
  font-size: 1.05rem;
  color: var(--text-400);
  max-width: 500px;
  line-height: 1.8;
}

/* Metric stats */
.hero-metrics {
  display: flex;
  gap: 2.75rem;
  padding: 1.5rem 0;
  border-top: 1px solid rgba(255,255,255,0.06);
  border-bottom: 1px solid rgba(255,255,255,0.06);
}
.metric-item { display: flex; flex-direction: column; gap: 0.2rem; }
.metric-value {
  font-family: var(--font-serif);
  font-size: 2.4rem;
  font-weight: 700;
  line-height: 1;
  background: var(--grad-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  display: flex;
  align-items: baseline;
}
.metric-value .plus { font-size: 1.2rem; margin-left: 1px; }
.metric-label {
  font-size: 0.68rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-500);
}
.hero-cta { display: flex; gap: 1rem; flex-wrap: wrap; }

/* Hero visual / orbital */
.hero-visual {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  height: 420px;
}
.orbit {
  position: absolute;
  border-radius: 50%;
  border: 1px solid;
}
.orbit-1 {
  width: 340px; height: 340px;
  border-color: rgba(79,126,240,0.15);
  animation: orbitSpin 22s linear infinite;
}
.orbit-2 {
  width: 260px; height: 260px;
  border-color: rgba(34,211,238,0.12);
  animation: orbitSpin 16s linear infinite reverse;
}
.orbit-3 {
  width: 430px; height: 430px;
  border-color: rgba(79,126,240,0.06);
  animation: orbitSpin 35s linear infinite;
}
@keyframes orbitSpin {
  from { transform: rotate(0deg); }
  to   { transform: rotate(360deg); }
}
/* Orbital dots */
.orbit-1::before {
  content: '';
  position: absolute;
  top: -5px; left: 50%;
  width: 10px; height: 10px;
  background: var(--blue);
  border-radius: 50%;
  box-shadow: 0 0 12px var(--blue);
  transform: translateX(-50%);
}
.orbit-2::after {
  content: '';
  position: absolute;
  bottom: -4px; left: 50%;
  width: 7px; height: 7px;
  background: var(--cyan);
  border-radius: 50%;
  box-shadow: 0 0 10px var(--cyan);
  transform: translateX(-50%);
}
.hero-profile {
  width: 210px; height: 210px;
  border-radius: 50%;
  object-fit: cover;
  object-position: center top;
  position: relative;
  z-index: 2;
  border: 3px solid var(--bg-950);
  box-shadow:
    0 0 0 1px rgba(79,126,240,0.35),
    0 24px 60px rgba(0,0,0,0.5);
}
.hero-profile-placeholder {
  width: 210px; height: 210px;
  border-radius: 50%;
  background: var(--grad-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-serif);
  font-size: 3.5rem;
  font-weight: 700;
  color: white;
  position: relative;
  z-index: 2;
  box-shadow:
    0 0 0 1px rgba(79,126,240,0.35),
    0 24px 60px rgba(0,0,0,0.5);
}
/* Floating badges on visual */
.hero-float-badge {
  position: absolute;
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-md);
  padding: 0.625rem 1rem;
  backdrop-filter: blur(12px);
  z-index: 3;
  box-shadow: var(--shadow-md);
}
.hfb-1 {
  top: 28px; right: -10px;
  animation: floatY 4s ease-in-out infinite;
}
.hfb-2 {
  bottom: 50px; left: -20px;
  animation: floatY 5s ease-in-out infinite 1.5s;
}
@keyframes floatY {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-8px); }
}
.hfb-title { font-size: 0.62rem; font-weight: 600; color: var(--text-500); letter-spacing: 0.08em; text-transform: uppercase; margin-bottom: 0.15rem; }
.hfb-value { font-size: 0.85rem; font-weight: 700; color: var(--text-100); }

/* Scroll hint */
.hero-scroll {
  position: absolute;
  bottom: 2.25rem; left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
  z-index: 1;
  opacity: 0.5;
}
.hero-scroll-text { font-size: 0.6rem; letter-spacing: 0.25em; text-transform: uppercase; color: var(--text-500); }
.scroll-mouse {
  width: 22px; height: 36px;
  border: 1px solid rgba(255,255,255,0.2);
  border-radius: 11px;
  display: flex;
  justify-content: center;
  padding-top: 8px;
}
.scroll-dot {
  width: 3px; height: 7px;
  background: var(--blue);
  border-radius: 2px;
  animation: scrollAnim 2.2s ease-in-out infinite;
}
@keyframes scrollAnim {
  0% { transform: translateY(0); opacity: 1; }
  100% { transform: translateY(11px); opacity: 0; }
}


/* ============================
   9. ABOUT
   ============================ */
#about { background: var(--bg-800); }
.about-grid {
  display: grid;
  grid-template-columns: 370px 1fr;
  gap: 5rem;
  align-items: start;
  margin-bottom: 4rem;
}
.about-img-col { position: relative; padding-bottom: 2rem; }
.about-img-frame {
  border-radius: var(--radius-lg);
  overflow: hidden;
  position: relative;
}
.about-img-frame img {
  width: 100%; height: 460px;
  object-fit: cover;
  object-position: center top;
  border-radius: var(--radius-lg);
  transition: transform 0.6s var(--ease);
}
.about-img-frame:hover img { transform: scale(1.03); }
.about-img-frame::after {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: var(--radius-lg);
  border: 1px solid rgba(79,126,240,0.2);
  pointer-events: none;
}
.about-stat-card {
  position: absolute;
  bottom: 0; right: -1.75rem;
  background: var(--bg-700);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-md);
  padding: 1.25rem 1.5rem;
  text-align: center;
  box-shadow: var(--shadow-md);
}
.about-stat-num {
  font-family: var(--font-serif);
  font-size: 2.5rem;
  font-weight: 700;
  background: var(--grad-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  line-height: 1;
}
.about-stat-lbl {
  font-size: 0.72rem;
  font-weight: 600;
  color: var(--text-400);
  margin-top: 0.3rem;
  white-space: nowrap;
}
.about-text-col { padding-top: 0.5rem; }
.about-bio p {
  font-size: 0.975rem;
  color: var(--text-400);
  line-height: 1.85;
  margin-bottom: 1rem;
}
.about-bio strong { color: var(--text-100); font-weight: 600; }

.expertise-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.75rem;
  margin-top: 1.75rem;
}
.exp-item {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.875rem 1rem;
  background: rgba(79,126,240,0.05);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-md);
  font-size: 0.82rem;
  font-weight: 500;
  color: var(--text-200);
  transition: var(--trans);
}
.exp-item:hover {
  background: rgba(79,126,240,0.1);
  border-color: rgba(79,126,240,0.3);
  transform: translateY(-2px);
}
.exp-item-icon { font-size: 1.1rem; flex-shrink: 0; }

/* Affiliations */
.affiliations-section { padding-top: 3rem; border-top: 1px solid rgba(255,255,255,0.05); }
.affiliations-label {
  font-size: 0.67rem;
  font-weight: 700;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--text-500);
  text-align: center;
  margin-bottom: 2rem;
}
.affiliations-row {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 3rem;
  flex-wrap: wrap;
}
.affil-logo {
  height: 34px; width: auto;
  filter: grayscale(1) brightness(0.5);
  transition: var(--trans);
  object-fit: contain;
}
.affil-logo:hover {
  filter: grayscale(0) brightness(1);
  transform: translateY(-3px);
}
/* Text fallback for affiliation logos */
.affil-text {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--text-500);
  letter-spacing: 0.06em;
  transition: var(--trans);
  padding: 0.4rem 0.875rem;
  border: 1px solid rgba(255,255,255,0.06);
  border-radius: var(--radius-pill);
}
.affil-text:hover {
  color: var(--text-200);
  border-color: rgba(79,126,240,0.25);
  background: rgba(79,126,240,0.07);
}


/* ============================
   10. EXPERIENCE
   ============================ */
#experience { background: var(--bg-900); }
.exp-layout {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 5rem;
  align-items: start;
}

/* Timeline */
.timeline {
  position: relative;
  padding-left: 2.25rem;
  margin-top: 2rem;
}
.timeline::before {
  content: '';
  position: absolute;
  left: 0; top: 10px; bottom: 0;
  width: 1px;
  background: linear-gradient(to bottom, var(--blue) 0%, rgba(79,126,240,0.15) 80%, transparent 100%);
}
.tl-item {
  position: relative;
  margin-bottom: 2.75rem;
  transition: var(--trans);
}
.tl-item:last-child { margin-bottom: 0; }
.tl-dot {
  position: absolute;
  left: -2.5rem; top: 4px;
  width: 15px; height: 15px;
  border-radius: 50%;
  background: var(--bg-800);
  border: 2px solid var(--text-500);
  transition: var(--trans);
}
.tl-dot.active {
  background: var(--blue);
  border-color: var(--blue);
  box-shadow: 0 0 16px rgba(79,126,240,0.6);
}
.tl-head {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 1rem;
  margin-bottom: 0.75rem;
}
.tl-role {
  font-size: 1rem;
  font-weight: 700;
  color: var(--text-100);
  margin-bottom: 0.2rem;
}
.tl-company {
  font-size: 0.85rem;
  color: var(--cyan);
  font-weight: 500;
}
.tl-period {
  font-size: 0.72rem;
  color: var(--text-500);
  white-space: nowrap;
  flex-shrink: 0;
  padding: 0.25rem 0.75rem;
  background: rgba(255,255,255,0.04);
  border: 1px solid rgba(255,255,255,0.07);
  border-radius: var(--radius-pill);
}
.tl-bullets { display: flex; flex-direction: column; gap: 0.5rem; }
.tl-bullets li {
  font-size: 0.87rem;
  color: var(--text-400);
  line-height: 1.72;
  padding-left: 1.25rem;
  position: relative;
}
.tl-bullets li::before {
  content: '';
  position: absolute;
  left: 0; top: 0.65em;
  width: 5px; height: 5px;
  border-radius: 50%;
  background: var(--blue);
  opacity: 0.55;
}

/* Education cards */
.edu-cards {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
  margin-top: 2rem;
}
.edu-card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-lg);
  padding: 1.625rem;
  transition: var(--trans);
  backdrop-filter: blur(12px);
}
.edu-card:hover {
  border-color: rgba(79,126,240,0.3);
  transform: translateY(-3px);
  box-shadow: var(--shadow-glow);
}
.edu-degree-tag {
  display: inline-block;
  font-size: 0.65rem;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--gold);
  margin-bottom: 0.6rem;
  padding: 0.2rem 0.6rem;
  background: rgba(245,158,11,0.1);
  border: 1px solid rgba(245,158,11,0.2);
  border-radius: var(--radius-pill);
}
.edu-title { font-size: 1.1rem; font-weight: 700; color: var(--text-100); margin-bottom: 0.3rem; }
.edu-school { font-size: 0.875rem; color: var(--cyan); font-weight: 500; margin-bottom: 0.3rem; }
.edu-period { font-size: 0.78rem; color: var(--text-500); margin-bottom: 0.75rem; }
.edu-thesis {
  font-size: 0.83rem;
  color: var(--text-400);
  line-height: 1.6;
  padding-top: 0.875rem;
  border-top: 1px solid var(--card-border);
}
.edu-thesis strong { color: var(--text-200); }


/* ============================
   11. RESEARCH PROJECTS
   ============================ */
#projects { background: var(--bg-800); }
.filter-row {
  display: flex;
  gap: 0.625rem;
  flex-wrap: wrap;
  margin-bottom: 2.75rem;
}
.filter-btn {
  padding: 0.5rem 1.375rem;
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  color: var(--text-400);
  border: 1px solid rgba(255,255,255,0.08);
  border-radius: var(--radius-pill);
  background: rgba(255,255,255,0.03);
  transition: var(--trans);
}
.filter-btn:hover {
  color: var(--text-100);
  border-color: rgba(79,126,240,0.35);
  background: rgba(79,126,240,0.08);
}
.filter-btn.active {
  background: var(--grad-primary);
  color: white;
  border-color: transparent;
  box-shadow: 0 4px 14px rgba(79,126,240,0.35);
}
.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
  gap: 1.75rem;
}
.project-card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: var(--trans);
  backdrop-filter: blur(12px);
  display: flex;
  flex-direction: column;
}
.project-card:hover {
  border-color: rgba(79,126,240,0.3);
  transform: translateY(-6px);
  box-shadow: var(--shadow-lg), 0 0 0 1px rgba(79,126,240,0.1);
}
.project-card.hidden { display: none; }

/* Project image */
.proj-img {
  position: relative;
  height: 195px;
  overflow: hidden;
}
.proj-img img {
  width: 100%; height: 100%;
  object-fit: cover;
  transition: transform 0.55s var(--ease);
}
.project-card:hover .proj-img img { transform: scale(1.06); }
.proj-img-overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(to bottom, transparent 35%, rgba(4,9,26,0.88) 100%);
}
.proj-badge {
  position: absolute;
  top: 1rem; left: 1rem;
  padding: 0.28rem 0.75rem;
  background: rgba(4,9,26,0.75);
  border: 1px solid rgba(79,126,240,0.35);
  border-radius: var(--radius-pill);
  font-size: 0.67rem;
  font-weight: 700;
  letter-spacing: 0.09em;
  color: var(--cyan);
  backdrop-filter: blur(10px);
}
/* Image gradient fallbacks */
.proj-img.p-automotive { background: linear-gradient(135deg, #0b1e42 0%, #1a3068 50%, #0d2045 100%); }
.proj-img.p-psycho     { background: linear-gradient(135deg, #1a0f42 0%, #2d1b6c 50%, #1a0d42 100%); }
.proj-img.p-immersive  { background: linear-gradient(135deg, #0b2432 0%, #1a404a 50%, #0d2035 100%); }
.proj-img.p-review     { background: linear-gradient(135deg, #1a1e0b 0%, #2e3818 50%, #1a1d0d 100%); }

/* Icon overlays for no-image fallback */
.proj-img-icon {
  position: absolute;
  top: 50%; left: 50%;
  transform: translate(-50%, -50%);
  font-size: 3.5rem;
  opacity: 0.18;
  z-index: 0;
}

/* Project body */
.proj-body {
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 0.875rem;
  flex: 1;
}
.proj-title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--text-100);
  line-height: 1.45;
}
.proj-desc {
  font-size: 0.845rem;
  color: var(--text-400);
  line-height: 1.75;
}
.proj-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
}
.proj-tag {
  padding: 0.2rem 0.65rem;
  background: rgba(79,126,240,0.08);
  border: 1px solid rgba(79,126,240,0.18);
  border-radius: var(--radius-pill);
  font-size: 0.68rem;
  font-weight: 600;
  color: var(--blue-light);
}

/* Contributions accordion */
.proj-contrib-section {
  border-top: 1px solid var(--card-border);
  padding-top: 0.875rem;
  margin-top: 0.25rem;
}
.proj-contrib-toggle {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  font-size: 0.78rem;
  font-weight: 700;
  color: var(--blue);
  letter-spacing: 0.04em;
  text-transform: uppercase;
  transition: var(--trans);
  padding: 0;
}
.proj-contrib-toggle:hover { color: var(--cyan); }
.contrib-arrow {
  font-size: 0.7rem;
  transition: transform 0.35s var(--ease);
  opacity: 0.7;
}
.proj-contrib-toggle.open .contrib-arrow { transform: rotate(180deg); }
.proj-contrib-body {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.5s var(--ease);
}
.proj-contrib-body.open { max-height: 700px; }
.contrib-list {
  display: flex;
  flex-direction: column;
  gap: 0.55rem;
  padding-top: 0.875rem;
}
.contrib-list li {
  font-size: 0.8rem;
  color: var(--text-400);
  line-height: 1.65;
  padding-left: 1.3rem;
  position: relative;
}
.contrib-list li::before {
  content: '';
  position: absolute;
  left: 0; top: 0.52em;
  width: 7px; height: 7px;
  border-radius: 50%;
  background: var(--grad-primary);
  flex-shrink: 0;
}

/* Project links */
.proj-links {
  display: flex;
  gap: 0.75rem;
  align-items: center;
  flex-wrap: wrap;
  margin-top: auto;
  padding-top: 0.25rem;
}
.proj-link {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  font-size: 0.76rem;
  font-weight: 700;
  padding: 0.375rem 0.875rem;
  border-radius: var(--radius-pill);
  transition: var(--trans);
  letter-spacing: 0.02em;
}
.proj-link.pdf {
  background: rgba(245,158,11,0.08);
  border: 1px solid rgba(245,158,11,0.25);
  color: var(--gold);
}
.proj-link.pdf:hover { background: rgba(245,158,11,0.18); transform: translateY(-1px); }
.proj-link.paper {
  background: rgba(79,126,240,0.08);
  border: 1px solid rgba(79,126,240,0.25);
  color: var(--blue);
}
.proj-link.paper:hover { background: rgba(79,126,240,0.18); transform: translateY(-1px); }
.proj-link.video {
  background: rgba(34,211,238,0.08);
  border: 1px solid rgba(34,211,238,0.25);
  color: var(--cyan);
}
.proj-link.video:hover { background: rgba(34,211,238,0.18); transform: translateY(-1px); }
.proj-link.conf-only {
  opacity: 0.45;
  cursor: default;
  border: 1px solid rgba(255,255,255,0.08);
  color: var(--text-500);
}


/* ============================
   12. PUBLICATIONS & PATENTS
   ============================ */
#publications { background: var(--bg-900); }
.pub-layout {
  display: grid;
  grid-template-columns: 1fr 380px;
  gap: 4.5rem;
  align-items: start;
}
.pub-list { display: flex; flex-direction: column; }
.pub-item {
  display: grid;
  grid-template-columns: 3rem 1fr;
  gap: 1.25rem;
  padding: 1.375rem 0.5rem;
  border-bottom: 1px solid rgba(255,255,255,0.05);
  transition: var(--trans);
  border-radius: var(--radius-sm);
}
.pub-item:last-child { border-bottom: none; }
.pub-item:hover {
  background: rgba(79,126,240,0.04);
  padding-left: 1rem;
}
.pub-num {
  font-family: var(--font-serif);
  font-size: 1.75rem;
  font-weight: 700;
  background: var(--grad-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  line-height: 1;
  padding-top: 0.2rem;
}
.pub-title {
  font-size: 0.935rem;
  font-weight: 600;
  color: var(--text-100);
  line-height: 1.5;
  margin-bottom: 0.35rem;
}
.pub-authors { font-size: 0.8rem; color: var(--text-400); margin-bottom: 0.25rem; }
.pub-authors strong { color: var(--cyan); }
.pub-venue { font-size: 0.77rem; color: var(--text-500); font-style: italic; margin-bottom: 0.5rem; }
.pub-meta { display: flex; align-items: center; gap: 0.75rem; flex-wrap: wrap; }
.pub-year {
  padding: 0.18rem 0.6rem;
  background: rgba(79,126,240,0.08);
  border-radius: var(--radius-pill);
  font-size: 0.68rem;
  font-weight: 700;
  color: var(--blue);
}
.pub-pdf {
  font-size: 0.72rem;
  font-weight: 700;
  color: var(--gold);
  padding: 0.18rem 0.6rem;
  background: rgba(245,158,11,0.07);
  border: 1px solid rgba(245,158,11,0.2);
  border-radius: var(--radius-pill);
  transition: var(--trans);
}
.pub-pdf:hover { background: rgba(245,158,11,0.16); }

/* Patents */
.patent-list {
  display: flex;
  flex-direction: column;
  gap: 1.1rem;
  margin-top: 1.75rem;
}
.patent-card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-md);
  padding: 1.375rem;
  transition: var(--trans);
  backdrop-filter: blur(12px);
}
.patent-card:hover {
  border-color: rgba(245,158,11,0.3);
  transform: translateY(-3px);
  box-shadow: 0 10px 24px rgba(0,0,0,0.35);
}
.patent-year {
  font-size: 0.67rem;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--gold);
  margin-bottom: 0.5rem;
}
.patent-title {
  font-size: 0.91rem;
  font-weight: 600;
  color: var(--text-100);
  line-height: 1.45;
  margin-bottom: 0.4rem;
}
.patent-num { font-size: 0.76rem; color: var(--text-500); font-family: monospace; }
.patent-inv { font-size: 0.75rem; color: var(--text-500); margin-top: 0.35rem; }


/* ============================
   13. SKILLS
   ============================ */
#skills { background: var(--bg-800); }
.skills-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.25rem;
}
.skill-cat {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-lg);
  padding: 1.625rem;
  transition: var(--trans);
  backdrop-filter: blur(12px);
}
.skill-cat:hover {
  border-color: rgba(79,126,240,0.28);
  transform: translateY(-3px);
  box-shadow: var(--shadow-glow-sm);
}
.skill-cat-head {
  display: flex;
  align-items: center;
  gap: 0.875rem;
  margin-bottom: 1.25rem;
}
.skill-cat-icon {
  width: 2.5rem; height: 2.5rem;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.15rem;
  flex-shrink: 0;
}
.icon-blue   { background: rgba(79,126,240,0.15); }
.icon-gold   { background: rgba(245,158,11,0.15); }
.icon-green  { background: rgba(52,211,153,0.15); }
.icon-purple { background: rgba(167,139,250,0.15); }
.icon-cyan   { background: rgba(34,211,238,0.15); }
.icon-rose   { background: rgba(251,113,133,0.15); }
.skill-cat-title {
  font-size: 0.88rem;
  font-weight: 700;
  color: var(--text-100);
  line-height: 1.35;
}
.skill-tags { display: flex; flex-wrap: wrap; gap: 0.45rem; }
.skill-tag {
  padding: 0.28rem 0.75rem;
  background: rgba(255,255,255,0.04);
  border: 1px solid rgba(255,255,255,0.07);
  border-radius: var(--radius-pill);
  font-size: 0.73rem;
  font-weight: 500;
  color: var(--text-400);
  transition: var(--trans);
}
.skill-tag:hover {
  background: rgba(79,126,240,0.1);
  border-color: rgba(79,126,240,0.25);
  color: var(--blue-light);
  transform: translateY(-1px);
}


/* ============================
   14. CONTACT
   ============================ */
#contact { background: var(--bg-900); }
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 5rem;
  align-items: center;
}
.contact-tagline {
  font-family: var(--font-serif);
  font-size: clamp(1.8rem, 4vw, 2.6rem);
  font-weight: 700;
  color: var(--text-100);
  line-height: 1.2;
  margin-bottom: 1rem;
}
.contact-tagline span {
  background: var(--grad-text);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.contact-desc {
  font-size: 0.96rem;
  color: var(--text-400);
  line-height: 1.8;
  margin-bottom: 2rem;
}
.contact-items { display: flex; flex-direction: column; gap: 1.125rem; margin-bottom: 2rem; }
.contact-item { display: flex; align-items: center; gap: 1rem; }
.contact-icon {
  width: 2.75rem; height: 2.75rem;
  background: rgba(79,126,240,0.08);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.05rem;
  flex-shrink: 0;
  transition: var(--trans);
}
.contact-item:hover .contact-icon {
  background: rgba(79,126,240,0.15);
  border-color: rgba(79,126,240,0.3);
}
.contact-label {
  font-size: 0.67rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--text-500);
  margin-bottom: 0.15rem;
}
.contact-val {
  font-size: 0.9rem;
  color: var(--text-200);
  font-weight: 500;
  transition: var(--trans);
}
a.contact-val:hover { color: var(--blue); }
.social-row { display: flex; gap: 0.75rem; flex-wrap: wrap; }
.social-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.625rem 1.25rem;
  background: rgba(255,255,255,0.04);
  border: 1px solid rgba(255,255,255,0.1);
  border-radius: var(--radius-pill);
  font-size: 0.825rem;
  font-weight: 600;
  color: var(--text-200);
  transition: var(--trans);
}
.social-btn:hover {
  background: rgba(79,126,240,0.1);
  border-color: rgba(79,126,240,0.3);
  color: var(--blue);
  transform: translateY(-2px);
}

/* CTA card */
.contact-cta-card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-xl);
  padding: 2.25rem;
  backdrop-filter: blur(20px);
  box-shadow: var(--shadow-lg);
}
.cta-header { display: flex; align-items: center; gap: 1rem; margin-bottom: 1rem; }
.cta-icon { font-size: 1.6rem; }
.cta-title { font-size: 1.15rem; font-weight: 700; color: var(--text-100); }
.cta-desc {
  font-size: 0.875rem;
  color: var(--text-400);
  line-height: 1.8;
  margin-bottom: 1.5rem;
}
.avail-badge {
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
  padding: 0.875rem 1rem;
  background: rgba(52,211,153,0.07);
  border: 1px solid rgba(52,211,153,0.2);
  border-radius: var(--radius-md);
  margin-bottom: 1.625rem;
}
.avail-dot {
  width: 9px; height: 9px;
  border-radius: 50%;
  background: var(--green);
  box-shadow: 0 0 10px var(--green);
  flex-shrink: 0;
  margin-top: 0.22rem;
  animation: pulseDot 2s ease-in-out infinite;
}
.avail-text { font-size: 0.83rem; color: var(--green); line-height: 1.5; }
.btn-cta-email {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.9rem;
  background: var(--grad-primary);
  color: white;
  border-radius: var(--radius-md);
  font-weight: 600;
  font-size: 0.9rem;
  margin-bottom: 0.75rem;
  transition: var(--trans);
  box-shadow: 0 4px 16px rgba(79,126,240,0.35);
}
.btn-cta-email:hover {
  transform: translateY(-2px);
  box-shadow: 0 10px 28px rgba(79,126,240,0.45);
}
.btn-cta-linkedin {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.9rem;
  background: rgba(255,255,255,0.04);
  border: 1px solid rgba(255,255,255,0.12);
  color: var(--text-200);
  border-radius: var(--radius-md);
  font-weight: 600;
  font-size: 0.9rem;
  transition: var(--trans);
}
.btn-cta-linkedin:hover {
  background: rgba(10,102,194,0.15);
  border-color: rgba(10,102,194,0.4);
  color: #7aabff;
  transform: translateY(-2px);
}


/* ============================
   15. FOOTER
   ============================ */
footer {
  background: var(--bg-950);
  border-top: 1px solid rgba(255,255,255,0.05);
  padding: 1.75rem 0;
}
.footer-inner {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 2rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
}
.footer-logo {
  font-family: var(--font-serif);
  font-size: 1.25rem;
  font-weight: 700;
  background: var(--grad-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.footer-copy { font-size: 0.78rem; color: var(--text-500); }
.footer-links { display: flex; gap: 1.75rem; }
.footer-links a { font-size: 0.78rem; color: var(--text-500); transition: var(--trans); }
.footer-links a:hover { color: var(--blue); }


/* ============================
   16. RESPONSIVE
   ============================ */
@media (max-width: 1100px) {
  .about-grid { grid-template-columns: 300px 1fr; gap: 3rem; }
  .skills-grid { grid-template-columns: repeat(2, 1fr); }
  .pub-layout { grid-template-columns: 1fr; gap: 3rem; }
  .exp-layout { grid-template-columns: 1fr; gap: 3rem; }
}

@media (max-width: 900px) {
  .projects-grid { grid-template-columns: 1fr 1fr; }
  .contact-grid { grid-template-columns: 1fr; gap: 3rem; }
}

@media (max-width: 768px) {
  :root { --section-y: 4rem; }
  .nav-links, .btn-nav-resume { display: none; }
  .nav-toggle { display: flex; }
  .hero-layout { grid-template-columns: 1fr; text-align: center; gap: 3rem; }
  .hero-text { align-items: center; }
  .hero-badge { align-self: center; }
  .hero-subtitle { max-width: 100%; }
  .hero-metrics { justify-content: center; }
  .hero-visual { order: -1; height: 340px; }
  .orbit-1 { width: 240px; height: 240px; }
  .orbit-2 { width: 185px; height: 185px; }
  .orbit-3 { width: 300px; height: 300px; }
  .hero-profile { width: 160px; height: 160px; }
  .hero-profile-placeholder { width: 160px; height: 160px; }
  .hfb-1, .hfb-2 { display: none; }
  .hero-cta { flex-direction: column; align-items: stretch; width: 100%; }
  .hero-cta a { text-align: center; justify-content: center; }
  .about-grid { grid-template-columns: 1fr; gap: 2rem; }
  .about-img-frame img { height: 300px; }
  .about-stat-card { bottom: -1rem; right: -0.5rem; }
  .expertise-grid { grid-template-columns: 1fr; }
  .projects-grid { grid-template-columns: 1fr; }
  .skills-grid { grid-template-columns: 1fr; }
}

@media (max-width: 480px) {
  .container { padding: 0 1.25rem; }
  .hero-metrics { gap: 1.75rem; }
  .footer-inner { flex-direction: column; text-align: center; }
  .footer-links { justify-content: center; }
}