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

/* ── Light Theme ─────────────────────────────────────────── */
:root {
  --bg-primary:        #ffffff;
  --bg-secondary:      #f5f5f7;
  --bg-card:           #ffffff;
  --bg-card-hover:     #fafafa;
  --text-primary:      #1d1d1f;
  --text-mid:          #6e6e73;
  --border:            #d2d2d7;
  --border-subtle:     rgba(0,0,0,0.06);
  --nav-bg:            rgba(255,255,255,0.82);
  --chip-bg:           #ffffff;
  --chip-shadow:       0 1px 4px rgba(0,0,0,0.1), 0 0 0 1px rgba(0,0,0,0.05);
  --card-shadow:       0 1px 4px rgba(0,0,0,0.08), 0 0 0 1px rgba(0,0,0,0.05);
  --card-shadow-hover: 0 8px 28px rgba(0,0,0,0.1);
  --toggle-bg:         #e5e5ea;
  --toggle-knob:       #ffffff;
  --accent:            #0071e3;
  --accent-h:          #0077ed;
  --font: -apple-system, BlinkMacSystemFont, 'SF Pro Display', 'Helvetica Neue', Arial, sans-serif;
  color-scheme: light;
}

/* ── Dark Theme ──────────────────────────────────────────── */
html[data-theme="dark"] {
  --bg-primary:        #000000;
  --bg-secondary:      #1c1c1e;
  --bg-card:           #1c1c1e;
  --bg-card-hover:     #2c2c2e;
  --text-primary:      #f5f5f7;
  --text-mid:          #86868b;
  --border:            rgba(255,255,255,0.12);
  --border-subtle:     rgba(255,255,255,0.08);
  --nav-bg:            rgba(28,28,30,0.9);
  --chip-bg:           #2c2c2e;
  --chip-shadow:       0 1px 4px rgba(0,0,0,0.5), 0 0 0 1px rgba(255,255,255,0.06);
  --card-shadow:       0 1px 4px rgba(0,0,0,0.5), 0 0 0 1px rgba(255,255,255,0.06);
  --card-shadow-hover: 0 8px 28px rgba(0,0,0,0.5);
  --toggle-bg:         #3a3a3c;
  --toggle-knob:       #ffffff;
  color-scheme: dark;
}

/* ── System preference (no manual override) ──────────────── */
@media (prefers-color-scheme: dark) {
  html:not([data-theme="light"]):not([data-theme="dark"]) {
    --bg-primary:        #000000;
    --bg-secondary:      #1c1c1e;
    --bg-card:           #1c1c1e;
    --bg-card-hover:     #2c2c2e;
    --text-primary:      #f5f5f7;
    --text-mid:          #86868b;
    --border:            rgba(255,255,255,0.12);
    --border-subtle:     rgba(255,255,255,0.08);
    --nav-bg:            rgba(28,28,30,0.9);
    --chip-bg:           #2c2c2e;
    --chip-shadow:       0 1px 4px rgba(0,0,0,0.5), 0 0 0 1px rgba(255,255,255,0.06);
    --card-shadow:       0 1px 4px rgba(0,0,0,0.5), 0 0 0 1px rgba(255,255,255,0.06);
    --card-shadow-hover: 0 8px 28px rgba(0,0,0,0.5);
    --toggle-bg:         #3a3a3c;
    --toggle-knob:       #ffffff;
    color-scheme: dark;
  }
}

html { scroll-behavior: smooth; }
body {
  font-family: var(--font);
  background: var(--bg-primary); color: var(--text-primary);
  overflow-x: hidden; -webkit-font-smoothing: antialiased;
  transition: background 0.3s ease, color 0.3s ease;
}
::selection { background: rgba(0,113,227,0.18); }
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: var(--bg-secondary); }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 3px; }

/* ── Nav ─────────────────────────────────────────────────── */
nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 200;
  height: 48px; display: flex; align-items: center; justify-content: center;
  background: var(--nav-bg);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  border-bottom: 1px solid var(--border-subtle);
  transition: background 0.3s ease;
}
.nav-inner {
  width: 100%; max-width: 1024px;
  display: flex; align-items: center; justify-content: space-between;
  padding: 0 1.5rem; gap: 1rem;
}
.nav-logo {
  display: inline-flex; align-items: center; justify-content: center;
  width: 32px; height: 32px; border-radius: 8px;
  background: linear-gradient(135deg, #0071e3, #34aadc);
  color: #fff; font-size: 0.78rem; font-weight: 700;
  letter-spacing: 0.04em; text-decoration: none; flex-shrink: 0;
  box-shadow: 0 1px 4px rgba(0,113,227,0.35);
}
.nav-links { display: flex; gap: 1.6rem; list-style: none; }
.nav-links a { font-size: 0.78rem; color: var(--text-mid); text-decoration: none; letter-spacing: 0.01em; transition: color 0.15s; }
.nav-links a:hover { color: var(--text-primary); }
.nav-right { display: flex; align-items: center; gap: 1rem; flex-shrink: 0; }
.nav-cta { font-size: 0.78rem; font-weight: 500; color: var(--accent); text-decoration: none; white-space: nowrap; }

/* ── Theme Toggle ────────────────────────────────────────── */
.theme-toggle {
  position: relative; width: 44px; height: 26px;
  background: var(--toggle-bg); border-radius: 980px;
  border: none; cursor: pointer; padding: 0; flex-shrink: 0;
  transition: background 0.25s ease;
}
.theme-toggle:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
.toggle-knob {
  position: absolute; top: 3px; left: 3px;
  width: 20px; height: 20px; border-radius: 50%;
  background: var(--toggle-knob);
  box-shadow: 0 1px 4px rgba(0,0,0,0.3);
  transition: transform 0.25s cubic-bezier(0.34,1.56,0.64,1);
  display: flex; align-items: center; justify-content: center;
  font-size: 11px; line-height: 1;
}
html[data-theme="dark"] .toggle-knob { transform: translateX(18px); }

/* ── Hero ────────────────────────────────────────────────── */
#hero {
  min-height: 100svh; display: flex; flex-direction: column;
  align-items: center; justify-content: center;
  text-align: center; padding: 6rem 2rem 4rem;
  background: var(--bg-primary); overflow: hidden; position: relative;
  transition: background 0.3s ease;
}
.hero-orb {
  position: absolute; width: 700px; height: 700px; border-radius: 50%;
  background: radial-gradient(circle, rgba(0,113,227,0.07) 0%, rgba(0,113,227,0) 70%);
  top: 50%; left: 50%; transform: translate(-50%,-60%); pointer-events: none;
}
.hero-eyebrow {
  font-size: 0.8rem; font-weight: 600; letter-spacing: 0.08em;
  text-transform: uppercase; color: var(--accent); margin-bottom: 1.2rem;
  opacity: 0; animation: fade-up 0.9s 0.1s forwards;
}
.hero-headline {
  font-size: clamp(2rem, 5.5vw, 5rem); font-weight: 700;
  letter-spacing: -0.04em; line-height: 1.0;
  color: var(--text-primary); white-space: nowrap;
  opacity: 0; animation: fade-up 0.9s 0.25s forwards;
}
.hero-headline em {
  font-style: normal;
  background: linear-gradient(135deg, #0071e3 0%, #34aadc 100%);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
}
.hero-sub {
  margin-top: 1.5rem; font-size: clamp(1rem, 2.5vw, 1.35rem);
  font-weight: 400; color: var(--text-mid); max-width: 600px; line-height: 1.5;
  opacity: 0; animation: fade-up 0.9s 0.4s forwards;
}
.hero-typing {
  margin-top: 0.5rem; font-size: 1.1rem; color: var(--accent);
  font-weight: 500; min-height: 1.6em;
  opacity: 0; animation: fade-up 0.9s 0.55s forwards;
}
.hero-cta {
  display: flex; gap: 1rem; justify-content: center;
  margin-top: 2.5rem; flex-wrap: wrap;
  opacity: 0; animation: fade-up 0.9s 0.7s forwards;
}
.btn-blue {
  padding: 0.75rem 1.8rem; border-radius: 980px; font-size: 0.9rem; font-weight: 500;
  background: var(--accent); color: #fff; text-decoration: none;
  transition: background 0.2s, transform 0.2s; white-space: nowrap;
}
.btn-blue:hover { background: var(--accent-h); transform: scale(1.02); }
.btn-outline {
  padding: 0.75rem 1.8rem; border-radius: 980px; font-size: 0.9rem; font-weight: 500;
  background: transparent; color: var(--accent); border: none;
  text-decoration: none; transition: color 0.2s, transform 0.2s; white-space: nowrap;
}
.btn-outline:hover { color: var(--accent-h); transform: scale(1.02); }
.btn-outline::after { content: ' →'; }
.scroll-cue {
  position: absolute; bottom: 2.5rem; left: 50%; transform: translateX(-50%);
  display: flex; flex-direction: column; align-items: center; gap: 6px;
  opacity: 0; animation: fade-in 1s 1.2s forwards;
}
.scroll-cue span { font-size: 0.7rem; letter-spacing: 0.12em; text-transform: uppercase; color: var(--border); }
.scroll-arrow {
  width: 18px; height: 18px;
  border-right: 1.5px solid var(--border); border-bottom: 1.5px solid var(--border);
  transform: rotate(45deg); animation: bounce-arrow 1.8s infinite;
}
@keyframes bounce-arrow { 0%,100%{transform:rotate(45deg) translate(0,0)} 50%{transform:rotate(45deg) translate(3px,3px)} }

/* ── Stats ────────────────────────────────────────────────── */
#stats { background: var(--bg-secondary); padding: 5rem 2rem; transition: background 0.3s ease; }
.stats-inner {
  max-width: 900px; margin: 0 auto;
  display: grid; grid-template-columns: repeat(4,1fr); gap: 0; text-align: center;
}
.stat-item { padding: 1rem; border-right: 1px solid var(--border); }
.stat-item:last-child { border-right: none; }
.stat-num { font-size: clamp(2.5rem,5vw,3.8rem); font-weight: 700; letter-spacing: -0.03em; color: var(--text-primary); line-height: 1; }
.stat-num sup { font-size: 0.5em; vertical-align: super; font-weight: 500; }
.stat-label { font-size: 0.78rem; color: var(--text-mid); margin-top: 0.5rem; letter-spacing: 0.04em; }

/* ── About ───────────────────────────────────────────────── */
#about { background: var(--bg-secondary); padding: 7rem 2rem; text-align: center; transition: background 0.3s ease; }
.about-eyebrow { font-size: 0.78rem; font-weight: 600; letter-spacing: 0.1em; text-transform: uppercase; color: var(--accent); margin-bottom: 1.2rem; }
.about-headline { font-size: clamp(2rem,5vw,3.8rem); font-weight: 700; letter-spacing: -0.03em; line-height: 1.1; max-width: 800px; margin: 0 auto; color: var(--text-primary); }
.about-body { max-width: 640px; margin: 2rem auto 0; font-size: 1.05rem; color: var(--text-mid); line-height: 1.7; }
.cred-chips { display: flex; flex-wrap: wrap; gap: 0.7rem; justify-content: center; margin-top: 2.5rem; }
.cred-chip {
  padding: 0.45rem 1.1rem; border-radius: 980px; font-size: 0.82rem; font-weight: 500;
  background: var(--chip-bg); color: var(--text-primary); box-shadow: var(--chip-shadow);
  transition: box-shadow 0.2s, transform 0.2s, background 0.3s;
}
.cred-chip:hover { box-shadow: var(--card-shadow-hover); transform: translateY(-1px); }

/* ── Experience ──────────────────────────────────────────── */
#experience { background: var(--bg-primary); padding: 7rem 2rem; transition: background 0.3s ease; }
.section-eyebrow { font-size: 0.78rem; font-weight: 600; letter-spacing: 0.1em; text-transform: uppercase; color: var(--accent); text-align: center; margin-bottom: 0.8rem; }
.section-headline { font-size: clamp(2rem,5vw,3.2rem); font-weight: 700; letter-spacing: -0.03em; text-align: center; margin-bottom: 4rem; color: var(--text-primary); }
.feature-grid {
  max-width: 1024px; margin: 0 auto;
  display: grid; grid-template-columns: repeat(3,1fr); gap: 1px;
  background: var(--border); border-radius: 18px; overflow: hidden;
}
.feature-cell { background: var(--bg-secondary); padding: 2.5rem 2rem; transition: background 0.2s; }
.feature-cell:hover { background: var(--bg-card-hover); }
.feature-icon { font-size: 2rem; margin-bottom: 1rem; }
.feature-title { font-size: 1.1rem; font-weight: 600; letter-spacing: -0.02em; margin-bottom: 0.5rem; color: var(--text-primary); }
.feature-org { font-size: 0.8rem; color: var(--accent); font-weight: 500; margin-bottom: 0.6rem; }
.feature-date { font-size: 0.75rem; color: var(--text-mid); margin-bottom: 0.7rem; }
.feature-desc { font-size: 0.85rem; color: var(--text-mid); line-height: 1.6; }

/* ── Scroll offset for fixed nav ─────────────────────────── */
section { scroll-margin-top: 70px; }

/* ── Credentials ─────────────────────────────────────────── */
#certs { background: var(--bg-primary); padding: 7rem 2rem; transition: background 0.3s ease; }
.certs-eyebrow { font-size: 0.78rem; font-weight: 600; letter-spacing: 0.1em; text-transform: uppercase; color: var(--text-mid); text-align: center; margin-bottom: 0.8rem; }
.certs-headline { font-size: clamp(2rem,5vw,3.2rem); font-weight: 700; letter-spacing: -0.03em; text-align: center; color: var(--text-primary); margin-bottom: 4rem; }
.certs-row { max-width: 960px; margin: 0 auto; display: grid; grid-template-columns: repeat(auto-fit, minmax(200px,1fr)); gap: 1.5rem; }
.cert-tile {
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: 18px; padding: 2rem 1.5rem; text-align: center;
  transition: background 0.2s, transform 0.2s, border-color 0.3s;
}
.cert-tile:hover { background: var(--bg-card-hover); transform: translateY(-4px); }
.cert-tile-icon { font-size: 2.5rem; margin-bottom: 1rem; }
.cert-tile-name { font-size: 1rem; font-weight: 600; color: var(--text-primary); margin-bottom: 0.3rem; }
.cert-tile-issuer { font-size: 0.8rem; color: var(--text-mid); margin-bottom: 0.8rem; }
.cert-tile-badge {
  display: inline-block; padding: 0.2rem 0.8rem; border-radius: 980px;
  font-size: 0.68rem; font-weight: 700; letter-spacing: 0.06em;
  background: rgba(52,210,120,0.15); color: #34d278; border: 1px solid rgba(52,210,120,0.3);
}
.cert-tile-badge.prev { background: rgba(255,255,255,0.08); color: rgba(255,255,255,0.35); border-color: rgba(255,255,255,0.12); }

/* ── Education tile (left-aligned layout) ────────────────── */
.cert-tile.education-tile { text-align: left; display: flex; gap: 1.5rem; align-items: center; }
.edu-icon { font-size: 2.5rem; flex-shrink: 0; }
.edu-school { font-size: 0.88rem !important; }
.edu-desc { font-size: 0.82rem; color: var(--text-mid); margin-top: 0.4rem; line-height: 1.5; }

/* ── Skills ──────────────────────────────────────────────── */
#skills { background: var(--bg-secondary); padding: 7rem 2rem; transition: background 0.3s ease; }
.skills-layout { max-width: 960px; margin: 0 auto; display: grid; grid-template-columns: 1fr 1fr; gap: 3rem; align-items: start; }
.skills-left h2 { font-size: clamp(2rem,4vw,3rem); font-weight: 700; letter-spacing: -0.03em; line-height: 1.1; margin-bottom: 1rem; color: var(--text-primary); }
.skills-left p { font-size: 1rem; color: var(--text-mid); line-height: 1.7; }
.skills-right { display: flex; flex-direction: column; gap: 1rem; }
.skill-row { display: flex; align-items: center; gap: 1rem; }
.skill-name { font-size: 0.88rem; font-weight: 500; width: 160px; flex-shrink: 0; color: var(--text-primary); }
.skill-track { flex: 1; height: 4px; background: var(--border); border-radius: 2px; overflow: hidden; }
.skill-fill { height: 100%; border-radius: 2px; width: 0; background: var(--accent); transition: width 1.3s cubic-bezier(0.22,1,0.36,1); }
.skill-pct { font-size: 0.78rem; color: var(--text-mid); width: 36px; text-align: right; flex-shrink: 0; }

/* ── Awards ──────────────────────────────────────────────── */
#awards { background: var(--bg-primary); padding: 7rem 2rem; transition: background 0.3s ease; }
.awards-marquee-wrap { max-width: 960px; margin: 3rem auto 0; display: grid; grid-template-columns: repeat(3,1fr); gap: 1.5rem; }
.award-tile {
  border: 1px solid var(--border); border-radius: 18px; padding: 2rem;
  background: var(--bg-card);
  transition: box-shadow 0.2s, transform 0.2s, border-color 0.3s, background 0.3s;
}
.award-tile:hover { box-shadow: var(--card-shadow-hover); transform: translateY(-3px); }
.award-emoji { font-size: 2rem; margin-bottom: 1rem; }
.award-name { font-size: 1rem; font-weight: 600; letter-spacing: -0.01em; margin-bottom: 0.4rem; color: var(--text-primary); }
.award-by { font-size: 0.8rem; color: var(--accent); margin-bottom: 0.3rem; }
.award-date { font-size: 0.75rem; color: var(--text-mid); }

/* ── Contact ─────────────────────────────────────────────── */
#contact { background: var(--bg-secondary); padding: 7rem 2rem; text-align: center; transition: background 0.3s ease; }
.contact-headline { font-size: clamp(2rem,5vw,3.5rem); font-weight: 700; letter-spacing: -0.03em; margin-bottom: 0.8rem; color: var(--text-primary); }
.contact-sub { font-size: 1.1rem; color: var(--text-mid); max-width: 480px; margin: 0 auto 2.5rem; line-height: 1.5; }
.contact-btns { display: flex; gap: 1rem; justify-content: center; flex-wrap: wrap; }
.contact-link {
  padding: 0.75rem 1.8rem; border-radius: 980px; font-size: 0.9rem; font-weight: 500;
  text-decoration: none; display: inline-flex; align-items: center; gap: 0.5rem; transition: all 0.2s;
}
.contact-link.primary { background: var(--accent); color: #fff; }
.contact-link.primary:hover { background: var(--accent-h); transform: scale(1.02); }

/* ── Footer ──────────────────────────────────────────────── */
footer { background: var(--bg-secondary); color: var(--text-mid); padding: 2rem; text-align: center; font-size: 0.75rem; line-height: 1.8; transition: background 0.3s ease, color 0.3s ease; }
footer a { color: var(--text-mid); text-decoration: none; margin: 0 0.7rem; }
footer a:hover { color: var(--text-primary); }
footer .divider { color: var(--border); margin: 0 0.3rem; }

/* ── Animations ──────────────────────────────────────────── */
@keyframes fade-up { from{opacity:0;transform:translateY(24px)} to{opacity:1;transform:translateY(0)} }
@keyframes fade-in  { from{opacity:0} to{opacity:1} }
.reveal { opacity:0; transform:translateY(20px); transition: opacity 0.8s ease, transform 0.8s ease; }
.reveal.visible { opacity:1; transform:translateY(0); }

/* ── Responsive ──────────────────────────────────────────── */
@media (max-width: 768px) {
  .stats-inner { grid-template-columns: repeat(2,1fr); }
  .stat-item { border-right:none; border-bottom:1px solid var(--border); }
  .feature-grid { grid-template-columns:1fr; }
  .skills-layout { grid-template-columns:1fr; }
  .awards-marquee-wrap { grid-template-columns:1fr; }
  .nav-links { display:none; }
}