/* ================================================================
   Meghamsh Teja – PhD Student Website
   Neuroimmunology Theme · Purples · Teals · Modern Minimalist
   ================================================================ */

/* ── Custom Properties ──────────────────────────────────────────── */
:root {
  --clr-bg:          #0d0a14;
  --clr-bg-alt:      #120e1e;
  --clr-surface:     #1a1430;
  --clr-surface-alt: #211940;
  --clr-purple-deep: #2D1B4E;
  --clr-purple:      #4A3073;
  --clr-purple-mid:  #6B4FA8;
  --clr-teal:        #00D4D4;
  --clr-teal-light:  #00BCD4;
  --clr-teal-dim:    rgba(0, 212, 212, 0.12);
  --clr-accent:      #A78BFA;
  --clr-text:        #e8e2f8;
  --clr-text-muted:  #9a90c4;
  --clr-border:      rgba(107, 79, 168, 0.25);
  --clr-border-teal: rgba(0, 212, 212, 0.20);

  --font-sans:    'Inter', system-ui, sans-serif;
  --font-display: 'Space Grotesk', system-ui, sans-serif;

  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 20px;
  --radius-xl: 28px;

  --shadow-glow-teal:   0 0 30px rgba(0, 212, 212, 0.15);
  --shadow-glow-purple: 0 0 30px rgba(107, 79, 168, 0.25);
  --shadow-card:        0 4px 32px rgba(0, 0, 0, 0.4);

  --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

/* ── 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-color: var(--clr-bg);
  color: var(--clr-text);
  line-height: 1.7;
  overflow-x: hidden;
}

::selection { background: rgba(0, 212, 212, 0.25); color: var(--clr-teal); }

a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }
ul { list-style: none; }

/* ── Scrollbar ──────────────────────────────────────────────────── */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: var(--clr-bg); }
::-webkit-scrollbar-thumb { background: var(--clr-purple); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--clr-purple-mid); }

/* ── Container ──────────────────────────────────────────────────── */
.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* ── Reveal Animation ───────────────────────────────────────────── */
.reveal {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}
.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ── Buttons ────────────────────────────────────────────────────── */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 1.75rem;
  border-radius: var(--radius-md);
  font-family: var(--font-display);
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
  border: 2px solid transparent;
}
.btn--primary {
  background: linear-gradient(135deg, var(--clr-teal), var(--clr-teal-light));
  color: var(--clr-bg);
}
.btn--primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(0, 212, 212, 0.35);
}
.btn--outline {
  border-color: var(--clr-teal);
  color: var(--clr-teal);
  background: transparent;
}
.btn--outline:hover {
  background: var(--clr-teal-dim);
  transform: translateY(-2px);
}

/* ── Tags ───────────────────────────────────────────────────────── */
.tag {
  display: inline-block;
  padding: 0.3rem 0.85rem;
  background: var(--clr-teal-dim);
  border: 1px solid var(--clr-border-teal);
  color: var(--clr-teal);
  border-radius: 100px;
  font-size: 0.8rem;
  font-weight: 500;
  letter-spacing: 0.02em;
}
.tag--sm { padding: 0.2rem 0.6rem; font-size: 0.72rem; }

/* ── Section Shared Styles ──────────────────────────────────────── */
.section { padding: 6rem 0; }
.section:nth-child(odd) { background: var(--clr-bg); }
.section:nth-child(even) { background: var(--clr-bg-alt); }

.section__header { margin-bottom: 3rem; }
.section__tag {
  display: inline-block;
  font-family: var(--font-display);
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--clr-teal);
  margin-bottom: 0.75rem;
}
.section__title {
  font-family: var(--font-display);
  font-size: clamp(1.6rem, 3vw, 2.4rem);
  font-weight: 700;
  color: var(--clr-text);
  line-height: 1.2;
}

/* ══════════════════════════════════════════════════════════════════
   NAVIGATION
   ══════════════════════════════════════════════════════════════════ */
.nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 1000;
  padding: 0.9rem 0;
  transition: background var(--transition), backdrop-filter var(--transition), box-shadow var(--transition);
}
.nav.scrolled {
  background: rgba(13, 10, 20, 0.92);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  box-shadow: 0 1px 0 var(--clr-border);
}
.nav__container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.nav__logo {
  font-family: var(--font-display);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--clr-teal);
  letter-spacing: 0.05em;
}
.nav__links {
  display: flex;
  align-items: center;
  gap: 0.25rem;
}
.nav__link {
  padding: 0.45rem 0.9rem;
  border-radius: var(--radius-sm);
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--clr-text-muted);
  transition: var(--transition);
}
.nav__link:hover,
.nav__link.active { color: var(--clr-text); background: rgba(255,255,255,0.06); }
.nav__link--cta {
  color: var(--clr-teal);
  border: 1.5px solid var(--clr-border-teal);
  margin-left: 0.5rem;
}
.nav__link--cta:hover { background: var(--clr-teal-dim); color: var(--clr-teal); }

/* Mobile toggle */
.nav__toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 36px; height: 36px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}
.nav__toggle span {
  display: block;
  width: 100%; height: 2px;
  background: var(--clr-text);
  border-radius: 2px;
  transition: 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); }

/* ══════════════════════════════════════════════════════════════════
   HERO
   ══════════════════════════════════════════════════════════════════ */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  overflow: hidden;
  background: radial-gradient(ellipse at 60% 40%, rgba(74,48,115,0.25) 0%, transparent 65%),
              radial-gradient(ellipse at 20% 80%, rgba(0,212,212,0.08) 0%, transparent 55%),
              var(--clr-bg);
}
.hero__canvas {
  position: absolute;
  inset: 0;
  width: 100%; height: 100%;
  opacity: 0.5;
  pointer-events: none;
}
.hero__content {
  position: relative;
  z-index: 1;
  max-width: 1100px;
  margin: 0 auto;
  padding: 6rem 1.5rem 4rem;
  width: 100%;
}
.hero__greeting {
  font-size: 1rem;
  font-weight: 500;
  color: var(--clr-teal);
  letter-spacing: 0.08em;
  margin-bottom: 0.75rem;
}
.hero__name {
  font-family: var(--font-display);
  font-size: clamp(3rem, 8vw, 6rem);
  font-weight: 700;
  line-height: 1.0;
  margin-bottom: 1.25rem;
  letter-spacing: -0.02em;
}
.hero__name--accent { color: var(--clr-teal); }

.hero__roles {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  font-family: var(--font-display);
  font-size: clamp(1rem, 2.5vw, 1.35rem);
  color: var(--clr-text-muted);
  margin-bottom: 1.5rem;
}
.hero__role-dynamic {
  color: var(--clr-accent);
  font-weight: 500;
  border-right: 2px solid var(--clr-accent);
  padding-right: 4px;
  white-space: nowrap;
}

.hero__tagline {
  max-width: 560px;
  font-size: clamp(0.95rem, 1.5vw, 1.1rem);
  color: var(--clr-text-muted);
  margin-bottom: 2.25rem;
  line-height: 1.75;
}
.hero__tagline .highlight { color: var(--clr-teal); font-weight: 500; }

.hero__cta { display: flex; gap: 1rem; flex-wrap: wrap; margin-bottom: 2.5rem; }

.hero__affiliations {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-size: 0.8rem;
  color: var(--clr-text-muted);
}
.affil {
  padding: 0.25rem 0.75rem;
  border: 1px solid var(--clr-border);
  border-radius: 100px;
}
.affil-sep { color: var(--clr-border); }

/* Scroll hint */
.hero__scroll-hint {
  position: absolute;
  bottom: 2rem; left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.7rem;
  letter-spacing: 0.12em;
  color: var(--clr-text-muted);
  text-transform: uppercase;
  animation: fadeInUp 1s 1.5s both;
}
.scroll-line {
  width: 1px; height: 40px;
  background: linear-gradient(to bottom, var(--clr-teal), transparent);
  animation: scrollLine 1.8s ease-in-out infinite;
}
@keyframes scrollLine {
  0%   { transform: scaleY(0); transform-origin: top; }
  50%  { transform: scaleY(1); transform-origin: top; }
  51%  { transform: scaleY(1); transform-origin: bottom; }
  100% { transform: scaleY(0); transform-origin: bottom; }
}
@keyframes fadeInUp {
  from { opacity: 0; transform: translateX(-50%) translateY(16px); }
  to   { opacity: 1; transform: translateX(-50%) translateY(0); }
}

/* ══════════════════════════════════════════════════════════════════
   ABOUT
   ══════════════════════════════════════════════════════════════════ */
.about__grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3rem;
  align-items: start;
}
.about__text p { color: var(--clr-text-muted); margin-bottom: 1rem; }
.about__text p strong { color: var(--clr-text); }
.about__interests { display: flex; flex-wrap: wrap; gap: 0.5rem; margin-top: 1.5rem; }

.about__stats { display: grid; grid-template-columns: 1fr 1fr; gap: 1rem; }
.stat-card {
  background: var(--clr-surface);
  border: 1px solid var(--clr-border);
  border-radius: var(--radius-md);
  padding: 1.5rem 1.25rem;
  text-align: center;
  transition: var(--transition);
}
.stat-card:hover {
  border-color: var(--clr-border-teal);
  box-shadow: var(--shadow-glow-teal);
  transform: translateY(-3px);
}
.stat-card__icon { font-size: 1.5rem; margin-bottom: 0.5rem; }
.stat-card__number {
  font-family: var(--font-display);
  font-size: 2rem;
  font-weight: 700;
  color: var(--clr-teal);
  line-height: 1;
  margin-bottom: 0.35rem;
}
.stat-card__label { font-size: 0.78rem; color: var(--clr-text-muted); }

/* ══════════════════════════════════════════════════════════════════
   RESEARCH
   ══════════════════════════════════════════════════════════════════ */
.research__badge {
  display: inline-block;
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--clr-teal);
  border: 1px solid var(--clr-border-teal);
  border-radius: 100px;
  padding: 0.2rem 0.8rem;
  margin-bottom: 1rem;
}
.research__badge--past { color: var(--clr-text-muted); border-color: var(--clr-border); }

.research__card {
  background: var(--clr-surface);
  border: 1px solid var(--clr-border);
  border-radius: var(--radius-lg);
  padding: 2rem;
  margin-bottom: 0.5rem;
  transition: var(--transition);
}
.research__card:hover {
  border-color: var(--clr-border-teal);
  box-shadow: var(--shadow-glow-teal);
}
.research__card--featured {
  border-color: rgba(0, 212, 212, 0.3);
  background: linear-gradient(135deg, var(--clr-surface), rgba(0,212,212,0.04));
}

.research__card-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 1rem;
  margin-bottom: 1rem;
}
.research__card-header h3 {
  font-family: var(--font-display);
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--clr-text);
  margin-bottom: 0.25rem;
}
.research__lab { font-size: 0.85rem; color: var(--clr-teal); font-weight: 500; }

.research__status {
  flex-shrink: 0;
  font-size: 0.72rem;
  font-weight: 600;
  padding: 0.25rem 0.7rem;
  border-radius: 100px;
  background: rgba(0, 212, 212, 0.15);
  color: var(--clr-teal);
  border: 1px solid var(--clr-border-teal);
  white-space: nowrap;
}
.research__status--past {
  background: rgba(154, 144, 196, 0.1);
  color: var(--clr-text-muted);
  border-color: var(--clr-border);
}

.research__desc { font-size: 0.9rem; color: var(--clr-text-muted); margin-bottom: 1.25rem; line-height: 1.75; }

.research__highlights { display: flex; flex-direction: column; gap: 0.5rem; }
.research__highlight { display: flex; align-items: center; gap: 0.75rem; font-size: 0.85rem; color: var(--clr-text-muted); }
.research__highlight-icon { color: var(--clr-teal); font-size: 0.65rem; }

.research__current { margin-bottom: 1.5rem; }
.research__past { margin-bottom: 3rem; }

.research__focus-title {
  font-family: var(--font-display);
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--clr-text-muted);
  margin-bottom: 1.5rem;
  letter-spacing: 0.04em;
}
.research__focus-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1rem;
}

.focus-card {
  background: var(--clr-surface);
  border: 1px solid var(--clr-border);
  border-radius: var(--radius-md);
  padding: 1.5rem 1.25rem;
  transition: var(--transition);
}
.focus-card:hover {
  border-color: var(--clr-border-teal);
  transform: translateY(-4px);
  box-shadow: var(--shadow-glow-teal);
}
.focus-card__icon { font-size: 1.75rem; margin-bottom: 0.75rem; }
.focus-card h4 { font-family: var(--font-display); font-size: 0.95rem; font-weight: 600; margin-bottom: 0.5rem; }
.focus-card p { font-size: 0.8rem; color: var(--clr-text-muted); line-height: 1.6; }

/* ══════════════════════════════════════════════════════════════════
   PROJECTS
   ══════════════════════════════════════════════════════════════════ */
.projects__grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.25rem;
  margin-bottom: 2.5rem;
}
.project-card {
  background: var(--clr-surface);
  border: 1px solid var(--clr-border);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  transition: var(--transition);
}
.project-card:hover {
  border-color: var(--clr-border-teal);
  box-shadow: var(--shadow-glow-teal);
  transform: translateY(-4px);
}
.project-card__header {
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.project-card__category {
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--clr-accent);
}
.project-card__links a {
  color: var(--clr-text-muted);
  display: flex;
  align-items: center;
  transition: var(--transition);
}
.project-card__links a:hover { color: var(--clr-teal); }
.project-card__title {
  font-family: var(--font-display);
  font-size: 1rem;
  font-weight: 600;
  color: var(--clr-text);
}
.project-card__desc { font-size: 0.85rem; color: var(--clr-text-muted); line-height: 1.7; flex: 1; }
.project-card__tags { display: flex; flex-wrap: wrap; gap: 0.4rem; }

.projects__cta { text-align: center; }

/* ══════════════════════════════════════════════════════════════════
   SKILLS
   ══════════════════════════════════════════════════════════════════ */
.skills__grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.5rem;
}
.skills__group {
  background: var(--clr-surface);
  border: 1px solid var(--clr-border);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
  transition: var(--transition);
}
.skills__group:hover { border-color: var(--clr-border-teal); }
.skills__group-title {
  font-family: var(--font-display);
  font-size: 0.95rem;
  font-weight: 600;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 1.25rem;
  color: var(--clr-text);
}
.skills__group-icon { font-size: 1.1rem; }

.skill-list { display: flex; flex-direction: column; gap: 0.85rem; }
.skill-item { display: flex; align-items: center; gap: 0.85rem; }
.skill-item__name { font-size: 0.85rem; color: var(--clr-text-muted); min-width: 120px; }
.skill-item__bar {
  flex: 1;
  height: 5px;
  background: rgba(255,255,255,0.07);
  border-radius: 100px;
  overflow: hidden;
}
.skill-item__fill {
  height: 100%;
  width: 0;
  background: linear-gradient(90deg, var(--clr-teal), var(--clr-accent));
  border-radius: 100px;
  transition: width 1.2s cubic-bezier(0.4, 0, 0.2, 1);
}
.skill-item__fill.animated { width: var(--fill); }

.lab-skills { display: flex; flex-direction: column; gap: 0.6rem; }
.lab-skill {
  font-size: 0.85rem;
  color: var(--clr-text-muted);
  padding: 0.5rem 0.85rem;
  background: rgba(255,255,255,0.03);
  border-radius: var(--radius-sm);
  border-left: 2px solid var(--clr-teal);
  transition: var(--transition);
}
.lab-skill:hover {
  background: var(--clr-teal-dim);
  color: var(--clr-text);
  border-left-color: var(--clr-teal);
}

/* ══════════════════════════════════════════════════════════════════
   PUBLICATIONS
   ══════════════════════════════════════════════════════════════════ */
.publications__list { display: flex; flex-direction: column; gap: 1rem; margin-bottom: 1.5rem; }

.pub-card {
  background: var(--clr-surface);
  border: 1px solid var(--clr-border);
  border-radius: var(--radius-md);
  padding: 1.5rem 1.75rem;
  transition: var(--transition);
}
.pub-card:hover {
  border-color: var(--clr-border-teal);
  transform: translateX(4px);
}
.pub-card__meta {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-bottom: 0.5rem;
}
.pub-card__type {
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--clr-teal);
}
.pub-card__year { font-size: 0.78rem; color: var(--clr-text-muted); }
.pub-card__title { font-family: var(--font-display); font-size: 0.95rem; font-weight: 600; color: var(--clr-text); margin-bottom: 0.35rem; }
.pub-card__authors { font-size: 0.82rem; color: var(--clr-text-muted); margin-bottom: 0.2rem; }
.pub-card__venue { font-size: 0.82rem; color: var(--clr-accent); font-style: italic; }

.publications__note {
  font-size: 0.85rem;
  color: var(--clr-text-muted);
  text-align: center;
}
.publications__note a { color: var(--clr-teal); border-bottom: 1px solid transparent; transition: var(--transition); }
.publications__note a:hover { border-bottom-color: var(--clr-teal); }

/* ══════════════════════════════════════════════════════════════════
   CONTACT
   ══════════════════════════════════════════════════════════════════ */
.contact__grid {
  display: grid;
  grid-template-columns: 1fr 1.4fr;
  gap: 3rem;
  align-items: start;
}
.contact__intro p { color: var(--clr-text-muted); font-size: 1rem; line-height: 1.8; }
.contact__links { display: flex; flex-direction: column; gap: 0.75rem; }

.contact-link {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 1rem 1.25rem;
  background: var(--clr-surface);
  border: 1px solid var(--clr-border);
  border-radius: var(--radius-md);
  transition: var(--transition);
}
.contact-link:hover {
  border-color: var(--clr-border-teal);
  background: var(--clr-teal-dim);
  transform: translateX(4px);
}
.contact-link__icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 42px; height: 42px;
  background: rgba(0, 212, 212, 0.1);
  border-radius: var(--radius-sm);
  color: var(--clr-teal);
  flex-shrink: 0;
}
.contact-link__label { display: block; font-size: 0.72rem; color: var(--clr-text-muted); font-weight: 500; letter-spacing: 0.05em; text-transform: uppercase; }
.contact-link__value { display: block; font-size: 0.9rem; color: var(--clr-text); font-weight: 500; }

/* ══════════════════════════════════════════════════════════════════
   FOOTER
   ══════════════════════════════════════════════════════════════════ */
.footer {
  padding: 2rem 0;
  border-top: 1px solid var(--clr-border);
  text-align: center;
  font-size: 0.82rem;
  color: var(--clr-text-muted);
}
.footer__copy { margin-top: 0.25rem; }
.footer strong { color: var(--clr-text); }

/* ── Interactive Lab Section ────────────────────────────────────── */
.interactive-lab__desc {
  text-align: center;
  color: var(--clr-text-muted);
  max-width: 700px;
  margin: 0 auto 2rem;
  line-height: 1.8;
}

.interactive-lab__canvas-wrap {
  position: relative;
  border: 1px solid var(--clr-border-teal);
  border-radius: var(--radius-lg);
  overflow: hidden;
  background: rgba(13, 10, 20, 0.85);
  box-shadow: var(--shadow-glow-teal), var(--shadow-card);
}

.interactive-lab__canvas {
  display: block;
  width: 100%;
  height: 420px;
  cursor: crosshair;
}
.interactive-lab__canvas:focus {
  outline: 2px solid var(--clr-teal);
  outline-offset: 2px;
}

.interactive-lab__legend {
  position: absolute;
  top: 1rem;
  right: 1rem;
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

.legend-item {
  font-size: 0.72rem;
  font-weight: 500;
  font-family: var(--font-display);
  padding: 0.22rem 0.6rem;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  gap: 0.45rem;
}

.legend-item::before {
  content: '';
  width: 9px;
  height: 9px;
  border-radius: 50%;
  flex-shrink: 0;
}

.legend-item--homeostatic { color: #00d4d4; background: rgba(0, 212, 212, 0.10); }
.legend-item--homeostatic::before { background: #00d4d4; }
.legend-item--surveilling { color: #f0c040; background: rgba(240, 192, 64, 0.10); }
.legend-item--surveilling::before { background: #f0c040; }
.legend-item--activated   { color: #ff6b6b; background: rgba(255, 107, 107, 0.10); }
.legend-item--activated::before   { background: #ff6b6b; }

.interactive-lab__hint {
  text-align: center;
  padding: 0.55rem 1rem;
  font-size: 0.78rem;
  color: var(--clr-text-muted);
  background: rgba(0, 0, 0, 0.35);
  border-top: 1px solid var(--clr-border);
}

/* ══════════════════════════════════════════════════════════════════
   RESPONSIVE – TABLET
   ══════════════════════════════════════════════════════════════════ */
@media (max-width: 900px) {
  .about__grid { grid-template-columns: 1fr; }
  .about__stats { grid-template-columns: repeat(4, 1fr); }
  .research__focus-grid { grid-template-columns: repeat(2, 1fr); }
  .projects__grid { grid-template-columns: 1fr; }
  .skills__grid { grid-template-columns: 1fr; }
  .contact__grid { grid-template-columns: 1fr; }
}

/* ══════════════════════════════════════════════════════════════════
   RESPONSIVE – MOBILE
   ══════════════════════════════════════════════════════════════════ */
@media (max-width: 640px) {
  .section { padding: 4rem 0; }

  /* Nav mobile */
  .nav__toggle { display: flex; }
  .nav__links {
    position: fixed;
    inset: 0;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    background: rgba(13, 10, 20, 0.97);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    gap: 1rem;
    opacity: 0;
    pointer-events: none;
    transition: opacity var(--transition);
  }
  .nav__links.open { opacity: 1; pointer-events: all; }
  .nav__link { font-size: 1.3rem; padding: 0.75rem 2rem; }
  .nav__link--cta { margin-left: 0; }

  .about__stats { grid-template-columns: repeat(2, 1fr); }
  .research__focus-grid { grid-template-columns: 1fr; }
  .research__card-header { flex-direction: column; }

  .hero__cta { flex-direction: column; align-items: flex-start; }
  .hero__cta .btn { width: 100%; justify-content: center; }

  .skills__group { padding: 1.25rem; }
  .skill-item__name { min-width: 90px; font-size: 0.78rem; }
}

/* ══════════════════════════════════════════════════════════════════
   UTILITY
   ══════════════════════════════════════════════════════════════════ */
.sr-only {
  position: absolute;
  width: 1px; height: 1px;
  padding: 0; margin: -1px;
  overflow: hidden;
  clip: rect(0,0,0,0);
  border: 0;
}