/* ============================================
   DR. MITHLESH KUMAR MAHTO — Portfolio CSS
   Theme: Dark Luxury + Vivid Accents
   ============================================ */

@import url('https://fonts.googleapis.com/css2?family=Playfair+Display:ital,wght@0,700;0,900;1,700&family=DM+Sans:wght@300;400;500;600&family=Space+Mono:wght@400;700&display=swap');

/* ---------- CSS Variables ---------- */
:root {
  --bg-dark:     #0a0c14;
  --bg-card:     #111520;
  --bg-card2:    #161b2e;
  --border:      rgba(255,255,255,0.07);
  --accent1:     #f97316;   /* vivid orange */
  --accent2:     #38bdf8;   /* sky blue */
  --accent3:     #a78bfa;   /* purple */
  --accent4:     #34d399;   /* emerald */
  --accent5:     #f43f5e;   /* rose */
  --text-main:   #f0f4ff;
  --text-muted:  #8899bb;
  --text-soft:   #c8d4f0;
  --font-display: 'Playfair Display', serif;
  --font-body:   'DM Sans', sans-serif;
  --font-mono:   'Space Mono', monospace;
  --radius:      14px;
  --shadow:      0 8px 40px rgba(0,0,0,0.6);
}

/* ---------- Reset ---------- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  background: var(--bg-dark);
  color: var(--text-main);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.7;
  overflow-x: hidden;
}
a { color: inherit; text-decoration: none; }
ul { list-style: none; }

/* ---------- Particle Canvas ---------- */
#particles {
  position: fixed;
  top: 0; left: 0;
  width: 100%; height: 100%;
  z-index: 0;
  pointer-events: none;
}

/* ---------- Container ---------- */
.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 2rem;
  position: relative;
  z-index: 1;
}

/* ---------- Navbar ---------- */
#navbar {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1rem 2.5rem;
  background: rgba(10,12,20,0.85);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--border);
  transition: box-shadow 0.3s;
}
#navbar.scrolled { box-shadow: 0 4px 30px rgba(0,0,0,0.5); }

.nav-brand {
  font-family: var(--font-mono);
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--accent1);
  letter-spacing: 2px;
}
.nav-links {
  display: flex;
  gap: 2rem;
}
.nav-links a {
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--text-muted);
  letter-spacing: 0.5px;
  transition: color 0.2s;
}
.nav-links a:hover { color: var(--accent2); }
.hamburger {
  display: none;
  background: none; border: none;
  color: var(--text-main);
  font-size: 1.5rem;
  cursor: pointer;
}

/* ---------- Section Common ---------- */
section {
  padding: 6rem 0;
  position: relative;
  z-index: 1;
}
section:nth-child(even) { background: rgba(255,255,255,0.015); }

.section-header {
  margin-bottom: 3rem;
}
.section-tag {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--accent1);
  letter-spacing: 2px;
  text-transform: uppercase;
  display: block;
  margin-bottom: 0.5rem;
}
.section-header h2 {
  font-family: var(--font-display);
  font-size: clamp(2rem, 4vw, 3rem);
  font-weight: 900;
  color: var(--text-main);
  line-height: 1.15;
}

/* ---------- Reveal Animation ---------- */
.reveal {
  opacity: 0;
  transform: translateY(40px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}
.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ========== HERO ========== */
#hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 7rem 2.5rem 4rem;
  max-width: 1200px;
  margin: 0 auto;
  gap: 3rem;
}

.hero-content { flex: 1; max-width: 600px; }

.hero-badge {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  background: linear-gradient(135deg, var(--accent1), var(--accent5));
  padding: 0.35rem 1rem;
  border-radius: 50px;
  letter-spacing: 1.5px;
  margin-bottom: 1.5rem;
  animation: fadeSlideDown 0.8s 0.2s both;
}

.hero-name {
  font-family: var(--font-display);
  font-size: clamp(2.8rem, 6vw, 5rem);
  font-weight: 900;
  line-height: 1.05;
  margin-bottom: 1rem;
  animation: fadeSlideDown 0.8s 0.4s both;
}
.hero-name .accent {
  background: linear-gradient(135deg, var(--accent2), var(--accent3));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.hero-tagline {
  font-size: 1.05rem;
  color: var(--accent4);
  font-weight: 500;
  letter-spacing: 0.5px;
  margin-bottom: 0.4rem;
  animation: fadeSlideDown 0.8s 0.5s both;
}
.hero-sub {
  font-size: 0.9rem;
  color: var(--text-muted);
  margin-bottom: 2.5rem;
  animation: fadeSlideDown 0.8s 0.6s both;
}

.hero-stats {
  display: flex;
  gap: 1.2rem;
  flex-wrap: wrap;
  margin-bottom: 2.5rem;
  animation: fadeSlideDown 0.8s 0.7s both;
}
.stat-box {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1rem 1.4rem;
  text-align: center;
  min-width: 80px;
  transition: transform 0.3s, border-color 0.3s;
}
.stat-box:hover { transform: translateY(-4px); border-color: var(--accent2); }
.stat-num {
  display: block;
  font-family: var(--font-mono);
  font-size: 1.8rem;
  font-weight: 700;
  color: var(--accent2);
}
.stat-label {
  font-size: 0.7rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 1px;
}

.hero-cta {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  animation: fadeSlideDown 0.8s 0.85s both;
}
.btn-primary {
  background: linear-gradient(135deg, var(--accent1), var(--accent5));
  color: white;
  padding: 0.75rem 2rem;
  border-radius: 50px;
  font-weight: 600;
  font-size: 0.9rem;
  transition: transform 0.2s, box-shadow 0.2s;
  box-shadow: 0 4px 20px rgba(249,115,22,0.35);
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 8px 30px rgba(249,115,22,0.5); }
.btn-outline {
  border: 1.5px solid var(--accent2);
  color: var(--accent2);
  padding: 0.75rem 2rem;
  border-radius: 50px;
  font-weight: 600;
  font-size: 0.9rem;
  transition: background 0.2s, color 0.2s;
}
.btn-outline:hover { background: var(--accent2); color: var(--bg-dark); }

/* Hero Visual */
.hero-visual {
  position: relative;
  width: 320px; height: 320px;
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  animation: fadeIn 1s 0.5s both;
}
.hex-ring {
  position: absolute;
  border-radius: 50%;
  border: 1.5px solid;
  animation: spinRing linear infinite;
}
.ring1 { width: 280px; height: 280px; border-color: rgba(56,189,248,0.25); animation-duration: 20s; }
.ring2 { width: 220px; height: 220px; border-color: rgba(167,139,250,0.3); animation-duration: 15s; animation-direction: reverse; }
.ring3 { width: 160px; height: 160px; border-color: rgba(249,115,22,0.35); animation-duration: 10s; }

.avatar-circle {
  width: 110px; height: 110px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--accent1), var(--accent3));
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-display);
  font-size: 2rem;
  font-weight: 900;
  color: white;
  z-index: 2;
  box-shadow: 0 0 40px rgba(249,115,22,0.4), 0 0 80px rgba(167,139,250,0.2);
}

.orbit-dot {
  position: absolute;
  width: 12px; height: 12px;
  border-radius: 50%;
  animation: orbitDot linear infinite;
}
.dot1 { background: var(--accent1); width: 12px; height: 12px; animation-duration: 8s; }
.dot2 { background: var(--accent2); width: 8px; height: 8px; animation-duration: 12s; animation-direction: reverse; }
.dot3 { background: var(--accent3); width: 10px; height: 10px; animation-duration: 16s; }

/* ========== ABOUT ========== */
.about-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3rem;
  align-items: start;
}
.about-text p {
  color: var(--text-soft);
  margin-bottom: 1rem;
  font-size: 1rem;
}
.about-text strong { color: var(--accent2); }
.about-text em { color: var(--accent1); font-style: normal; font-weight: 600; }

.interests-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}
.interest-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1rem;
  text-align: center;
  font-size: 0.85rem;
  color: var(--text-muted);
  transition: transform 0.25s, border-color 0.25s, color 0.25s;
}
.interest-card:hover { transform: translateY(-3px); border-color: var(--accent3); color: var(--text-main); }
.int-icon { font-size: 1.5rem; margin-bottom: 0.3rem; }

/* ========== EDUCATION TIMELINE ========== */
.timeline { position: relative; padding-left: 3rem; }
.timeline::before {
  content: '';
  position: absolute;
  left: 1rem;
  top: 0; bottom: 0;
  width: 2px;
  background: linear-gradient(to bottom, var(--accent1), var(--accent3), var(--accent2));
}
.timeline-item {
  position: relative;
  margin-bottom: 2.5rem;
  display: flex;
  gap: 1.5rem;
  align-items: flex-start;
}
.tl-dot {
  position: absolute;
  left: -2.4rem;
  top: 0.4rem;
  width: 14px; height: 14px;
  border-radius: 50%;
  background: var(--accent1);
  border: 3px solid var(--bg-dark);
  box-shadow: 0 0 10px var(--accent1);
  flex-shrink: 0;
}
.tl-dot.gate { background: var(--accent4); box-shadow: 0 0 10px var(--accent4); }

.tl-year {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--accent1);
  min-width: 48px;
  padding-top: 0.2rem;
  font-weight: 700;
}
.tl-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.2rem 1.5rem;
  flex: 1;
  transition: border-color 0.3s;
}
.tl-card:hover { border-color: var(--accent2); }
.highlight-card { border-color: rgba(52,211,153,0.3); }

.tl-badge {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.65rem;
  font-weight: 700;
  padding: 0.2rem 0.7rem;
  border-radius: 4px;
  margin-bottom: 0.5rem;
  letter-spacing: 1px;
}
.tl-badge.phd  { background: rgba(249,115,22,0.2); color: var(--accent1); }
.tl-badge.mtech { background: rgba(56,189,248,0.2); color: var(--accent2); }
.tl-badge.be   { background: rgba(167,139,250,0.2); color: var(--accent3); }
.tl-badge.gate-badge { background: rgba(52,211,153,0.2); color: var(--accent4); }

.tl-card h3 { font-size: 1rem; font-weight: 600; margin-bottom: 0.3rem; }
.tl-inst { color: var(--accent2); font-size: 0.9rem; font-weight: 500; margin-bottom: 0.3rem; }
.tl-note { color: var(--text-muted); font-size: 0.85rem; }

/* ========== EXPERIENCE ========== */
.exp-cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.5rem;
}
.exp-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.8rem;
  position: relative;
  overflow: hidden;
  transition: transform 0.3s, border-color 0.3s;
}
.exp-card:hover { transform: translateY(-5px); border-color: var(--accent3); }
.exp-card.current { border-color: rgba(52,211,153,0.4); }
.exp-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 3px;
  background: linear-gradient(to right, var(--accent1), var(--accent3));
}
.exp-card.current::before { background: linear-gradient(to right, var(--accent4), var(--accent2)); }

.exp-badge {
  display: inline-block;
  background: var(--accent4);
  color: var(--bg-dark);
  font-size: 0.65rem;
  font-weight: 700;
  padding: 0.2rem 0.6rem;
  border-radius: 4px;
  letter-spacing: 1px;
  margin-bottom: 0.8rem;
}
.exp-duration {
  font-family: var(--font-mono);
  font-size: 2rem;
  font-weight: 700;
  color: var(--accent1);
  line-height: 1;
  margin-bottom: 0.5rem;
}
.exp-card h3 { font-size: 1rem; font-weight: 600; margin-bottom: 0.3rem; }
.exp-loc { font-size: 0.85rem; color: var(--accent2); margin-bottom: 0.3rem; }
.exp-detail { font-size: 0.8rem; color: var(--text-muted); }

/* ========== RESEARCH ========== */
.research-block {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-left: 4px solid var(--accent1);
  border-radius: var(--radius);
  padding: 2rem;
}
.res-title {
  font-family: var(--font-display);
  font-size: 1.2rem;
  font-style: italic;
  color: var(--text-main);
  margin-bottom: 1rem;
}
.res-points { display: flex; flex-direction: column; gap: 1rem; }
.res-point {
  display: flex;
  gap: 1rem;
  align-items: flex-start;
}
.res-icon { font-size: 1rem; margin-top: 0.2rem; flex-shrink: 0; }
.res-point p { color: var(--text-soft); font-size: 0.95rem; }
.res-point strong { color: var(--accent2); }

.scholar-links {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  margin-top: 2.5rem;
}
.scholar-btn {
  padding: 0.55rem 1.4rem;
  border-radius: 50px;
  font-size: 0.85rem;
  font-weight: 600;
  border: 1.5px solid;
  transition: transform 0.2s, background 0.2s;
}
.scholar-btn:hover { transform: translateY(-2px); }
.scholar-btn.google { border-color: var(--accent1); color: var(--accent1); }
.scholar-btn.google:hover { background: var(--accent1); color: white; }
.scholar-btn.scopus { border-color: var(--accent2); color: var(--accent2); }
.scholar-btn.scopus:hover { background: var(--accent2); color: var(--bg-dark); }
.scholar-btn.resgate { border-color: var(--accent3); color: var(--accent3); }
.scholar-btn.resgate:hover { background: var(--accent3); color: white; }
.scholar-btn.orcid { border-color: var(--accent4); color: var(--accent4); }
.scholar-btn.orcid:hover { background: var(--accent4); color: var(--bg-dark); }

/* ========== PUBLICATIONS ========== */
.pub-filter {
  display: flex;
  gap: 0.8rem;
  margin-bottom: 2rem;
  flex-wrap: wrap;
}
.filter-btn {
  background: var(--bg-card);
  border: 1px solid var(--border);
  color: var(--text-muted);
  padding: 0.45rem 1.2rem;
  border-radius: 50px;
  font-size: 0.85rem;
  cursor: pointer;
  font-family: var(--font-body);
  transition: all 0.2s;
}
.filter-btn.active, .filter-btn:hover {
  background: var(--accent1);
  border-color: var(--accent1);
  color: white;
}

.pub-list { display: flex; flex-direction: column; gap: 1.2rem; }
.pub-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.4rem 1.8rem;
  display: flex;
  gap: 1.5rem;
  align-items: flex-start;
  transition: transform 0.25s, border-color 0.25s;
}
.pub-card:hover { transform: translateX(5px); border-color: var(--accent2); }
.pub-card.hidden { display: none; }

.pub-num {
  font-family: var(--font-mono);
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--accent1);
  opacity: 0.4;
  min-width: 32px;
  padding-top: 0.15rem;
}
.pub-content { flex: 1; }
.pub-journal {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--accent2);
  letter-spacing: 0.5px;
  text-transform: uppercase;
  margin-bottom: 0.3rem;
}
.pub-year {
  float: right;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-muted);
  background: rgba(255,255,255,0.05);
  padding: 0.1rem 0.5rem;
  border-radius: 4px;
}
.pub-title {
  font-size: 0.95rem;
  color: var(--text-soft);
  margin: 0.3rem 0 0.7rem;
  line-height: 1.5;
}
.pub-meta { display: flex; align-items: center; gap: 0.6rem; flex-wrap: wrap; }
.if-badge {
  font-size: 0.72rem;
  font-weight: 600;
  background: rgba(249,115,22,0.15);
  color: var(--accent1);
  padding: 0.2rem 0.6rem;
  border-radius: 4px;
  font-family: var(--font-mono);
}
.q-badge {
  font-size: 0.7rem;
  font-weight: 700;
  padding: 0.2rem 0.6rem;
  border-radius: 4px;
  font-family: var(--font-mono);
  letter-spacing: 1px;
}
.q-badge.q1 { background: rgba(52,211,153,0.15); color: var(--accent4); }
.q-badge.q2 { background: rgba(56,189,248,0.15); color: var(--accent2); }
.q-badge.q4 { background: rgba(255,255,255,0.07); color: var(--text-muted); }
.doi-link {
  font-size: 0.78rem;
  color: var(--accent3);
  border-bottom: 1px dashed rgba(167,139,250,0.4);
  padding-bottom: 1px;
  margin-left: auto;
  transition: color 0.2s;
}
.doi-link:hover { color: var(--text-main); }

/* ========== CONFERENCES ========== */
.conf-tabs {
  display: flex;
  gap: 0.5rem;
  margin-bottom: 2rem;
}
.conf-tab {
  background: var(--bg-card);
  border: 1px solid var(--border);
  color: var(--text-muted);
  padding: 0.5rem 1.5rem;
  border-radius: 50px;
  cursor: pointer;
  font-family: var(--font-body);
  font-size: 0.9rem;
  transition: all 0.2s;
}
.conf-tab.active, .conf-tab:hover {
  background: var(--accent3);
  border-color: var(--accent3);
  color: white;
}
.conf-list { display: none; flex-direction: column; gap: 1rem; }
.conf-list.active { display: flex; }

.conf-item {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.2rem 1.5rem;
  display: flex;
  gap: 1.2rem;
  align-items: flex-start;
  transition: border-color 0.3s;
}
.conf-item:hover { border-color: var(--accent3); }
.conf-type {
  font-size: 0.68rem;
  font-weight: 700;
  padding: 0.25rem 0.6rem;
  border-radius: 4px;
  letter-spacing: 1px;
  text-transform: uppercase;
  flex-shrink: 0;
  margin-top: 0.2rem;
}
.conf-type.oral { background: rgba(249,115,22,0.2); color: var(--accent1); }
.conf-type.poster { background: rgba(167,139,250,0.2); color: var(--accent3); }
.conf-title { font-size: 0.95rem; color: var(--text-soft); margin-bottom: 0.3rem; }
.conf-venue { font-size: 0.8rem; color: var(--text-muted); }

/* ========== ACHIEVEMENTS ========== */
.ach-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2rem;
}
.ach-col {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.8rem;
}
.ach-col h3 {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 1.2rem;
  color: var(--accent2);
}
.ach-list li {
  color: var(--text-muted);
  font-size: 0.9rem;
  padding: 0.5rem 0;
  border-bottom: 1px solid var(--border);
  padding-left: 1rem;
  position: relative;
}
.ach-list li::before {
  content: '▸';
  position: absolute;
  left: 0;
  color: var(--accent1);
}
.ach-list li:last-child { border-bottom: none; }

/* ========== CONTACT ========== */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1.2fr;
  gap: 3rem;
}
.contact-info { display: flex; flex-direction: column; gap: 1.5rem; }
.contact-item {
  display: flex;
  gap: 1rem;
  align-items: flex-start;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.2rem 1.5rem;
  transition: border-color 0.3s;
}
.contact-item:hover { border-color: var(--accent4); }
.c-icon { font-size: 1.5rem; flex-shrink: 0; }
.c-label {
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--text-muted);
  margin-bottom: 0.3rem;
}
.contact-item a {
  color: var(--accent2);
  font-size: 0.9rem;
  display: block;
  transition: color 0.2s;
}
.contact-item a:hover { color: var(--text-main); }
.contact-item p { color: var(--text-soft); font-size: 0.9rem; }

.contact-profiles h3 {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 1.2rem;
  color: var(--accent4);
  font-family: var(--font-mono);
  letter-spacing: 1px;
}
.profile-links { display: flex; flex-direction: column; gap: 0.8rem; }
.profile-link {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1rem 1.3rem;
  display: flex;
  align-items: center;
  gap: 0.8rem;
  transition: transform 0.25s, border-color 0.25s;
}
.profile-link:hover { transform: translateX(6px); }
.profile-link.gs:hover { border-color: var(--accent1); }
.profile-link.sc:hover { border-color: var(--accent2); }
.profile-link.rg:hover { border-color: var(--accent3); }
.profile-link.oc:hover { border-color: var(--accent4); }
.pl-icon { font-size: 1.2rem; }
.profile-link span:nth-child(2) { flex: 1; font-size: 0.9rem; color: var(--text-soft); }
.pl-stats {
  font-size: 0.72rem !important;
  color: var(--accent4) !important;
  font-family: var(--font-mono);
  background: rgba(52,211,153,0.1);
  padding: 0.15rem 0.6rem;
  border-radius: 4px;
}

/* ========== FOOTER ========== */
footer {
  background: var(--bg-card);
  border-top: 1px solid var(--border);
  text-align: center;
  padding: 2rem;
  color: var(--text-muted);
  font-size: 0.85rem;
  position: relative;
  z-index: 1;
}

/* ========== KEYFRAMES ========== */
@keyframes fadeSlideDown {
  from { opacity: 0; transform: translateY(-20px); }
  to   { opacity: 1; transform: translateY(0); }
}
@keyframes fadeIn {
  from { opacity: 0; }
  to   { opacity: 1; }
}
@keyframes spinRing {
  from { transform: rotate(0deg); }
  to   { transform: rotate(360deg); }
}
@keyframes orbitDot {
  0%   { transform: rotate(0deg) translateX(130px) rotate(0deg); }
  100% { transform: rotate(360deg) translateX(130px) rotate(-360deg); }
}

/* ========== RESPONSIVE ========== */
@media (max-width: 900px) {
  #hero { flex-direction: column; text-align: center; padding-top: 8rem; }
  .hero-cta, .hero-stats { justify-content: center; }
  .hero-visual { width: 240px; height: 240px; }
  .ring1 { width: 210px; height: 210px; }
  .ring2 { width: 165px; height: 165px; }
  .ring3 { width: 120px; height: 120px; }
  .about-grid { grid-template-columns: 1fr; }
  .contact-grid { grid-template-columns: 1fr; }
  .ach-grid { grid-template-columns: 1fr; }
}

@media (max-width: 650px) {
  .nav-links { display: none; flex-direction: column; position: absolute; top: 100%; left: 0; right: 0; background: rgba(10,12,20,0.98); padding: 1.5rem 2rem; gap: 1rem; border-bottom: 1px solid var(--border); }
  .nav-links.open { display: flex; }
  .hamburger { display: block; }
  .pub-card { flex-direction: column; }
  .pub-year { float: none; display: inline-block; margin-bottom: 0.3rem; }
  .timeline { padding-left: 2rem; }
  .timeline-item { gap: 0.8rem; }
  section { padding: 4rem 0; }
}