:root {
  --bg: #000000;
  --bg-alt: #1d1d1f;
  --surface: #1d1d1f;
  --surface-2: #2d2d2f;
  --border: rgba(255,255,255,0.08);
  --text: #f5f5f7;
  --text-secondary: #98989d;
  --text-tertiary: #424245;
  --accent: #2997ff;
  --accent-hover: #40a9ff;
  --accent-press: #0071e3;
  --accent-glow: rgba(41,151,255,0.12);
  --accent-glow-strong: rgba(41,151,255,0.22);
  --nav-bg: rgba(0,0,0,0.8);
  --nav-border: rgba(255,255,255,0.08);
  --shadow: 0 2px 12px rgba(0,0,0,0.4);
  --shadow-lg: 0 4px 24px rgba(0,0,0,0.5);
  --radius: 12px;
  --radius-lg: 16px;
  --transition: 0.35s cubic-bezier(0.25, 0.1, 0.25, 1);
  --transition-spring: 0.5s cubic-bezier(0.34, 1.56, 0.64, 1);
  --nav-height: 48px;
  --max-width: 1068px;
}

html.light {
  --bg: #f5f5f7;
  --bg-alt: #ffffff;
  --surface: #ffffff;
  --surface-2: #f5f5f7;
  --border: rgba(0,0,0,0.06);
  --text: #1d1d1f;
  --text-secondary: #6b6b70;
  --text-tertiary: #aeaeb2;
  --accent: #0071e3;
  --accent-hover: #0077ed;
  --accent-press: #0068c8;
  --accent-glow: rgba(0,113,227,0.08);
  --accent-glow-strong: rgba(0,113,227,0.16);
  --nav-bg: rgba(255,255,255,0.8);
  --nav-border: rgba(0,0,0,0.08);
  --shadow: 0 2px 12px rgba(0,0,0,0.04);
  --shadow-lg: 0 4px 24px rgba(0,0,0,0.06);
}

html.light .site-header.is-sticky { background: var(--nav-bg); }
html.light .site-header.is-sticky .nav-links.is-open { background: var(--bg-alt); }

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; border-radius: 4px; }

html { scroll-behavior: smooth; scroll-padding-top: var(--nav-height); }

body {
  background: var(--bg);
  color: var(--text);
  font-family: "Inter", -apple-system, BlinkMacSystemFont, system-ui, "Helvetica Neue", sans-serif;
  font-size: 1rem;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

body.menu-open { overflow: hidden; position: fixed; width: 100%; }

img { max-width: 100%; display: block; }
a { color: var(--accent); text-decoration: none; transition: color var(--transition); }
a:hover { color: var(--accent-hover); }
.hero-stat a { color: inherit; text-decoration: none; }

.container { max-width: var(--max-width); margin: 0 auto; padding: 0 24px; }
.section { padding: 120px 0; }
.section--alt { background: var(--bg-alt); }

/* Navigation */
.site-header {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  height: var(--nav-height); display: flex; align-items: center;
  transition: background var(--transition), border-color var(--transition);
  border-bottom: 1px solid transparent;
}
.site-header.is-sticky {
  background: var(--nav-bg);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  border-color: var(--nav-border);
}
.site-header .container {
  width: 100%; display: flex; align-items: center;
  justify-content: center; gap: 32px;
}
.nav-logo {
  display: flex; align-items: center; gap: 8px;
  text-decoration: none; color: inherit; margin-right: auto;
}
.nav-logo-mark {
  display: flex; align-items: center; justify-content: center;
  width: 36px; height: 36px; border-radius: 9999px;
  border: 1px solid var(--border);
  color: var(--text-secondary);
  font-size: 0.75rem; font-weight: 600;
  transition: transform var(--transition-spring), border-color var(--transition), color var(--transition);
  line-height: 1;
}
.nav-logo:hover .nav-logo-mark {
  border-color: var(--text-tertiary);
  color: var(--text);
}
.nav-links { display: flex; align-items: center; gap: 0; }
.nav-links a {
  font-size: 0.75rem; font-weight: 500; letter-spacing: 0.01em;
  color: var(--text-secondary); padding: 6px 16px;
  transition: color var(--transition); text-decoration: none;
}
.nav-links a:hover { color: var(--text); }
.nav-links a.is-active { color: var(--text); }
.nav-actions { display: flex; align-items: center; gap: 8px; margin-left: auto; }

.theme-toggle {
  display: flex; align-items: center; justify-content: center;
  width: 36px; height: 36px; border-radius: 9999px;
  background: transparent; border: 1px solid var(--border);
  color: var(--text-secondary); cursor: pointer;
  transition: all var(--transition);
}
.theme-toggle:hover { color: var(--text); border-color: var(--text-tertiary); }
.theme-toggle svg { width: 16px; height: 16px; }
html.light .theme-toggle .icon-moon { display: none; }
html.light .theme-toggle .icon-sun { display: block; }
.theme-toggle .icon-sun { display: none; }
.theme-toggle .icon-moon { display: block; }

.nav-toggle {
  display: none;
  flex-direction: column; justify-content: center; gap: 5px;
  width: 36px; height: 36px; background: none; border: none;
  cursor: pointer; padding: 4px; border-radius: 6px;
  transition: background var(--transition);
}
.nav-toggle:hover { background: var(--surface-2); }
.nav-toggle span {
  display: block; width: 22px; height: 2px;
  background: var(--text); border-radius: 2px;
  transition: transform var(--transition), opacity var(--transition);
  transform-origin: center;
}
.menu-open .nav-toggle span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.menu-open .nav-toggle span:nth-child(2) { opacity: 0; }
.menu-open .nav-toggle span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* Hero */
.s-hero {
  min-height: 100dvh; display: flex; align-items: center;
  position: relative; overflow: hidden; padding-top: var(--nav-height);
}
.s-hero::before {
  content: ''; position: absolute; inset: 0;
  background:
    radial-gradient(ellipse 70% 55% at 50% 40%, rgba(0,113,227,0.07) 0%, transparent 60%),
    radial-gradient(ellipse 40% 40% at 20% 80%, rgba(0,113,227,0.04) 0%, transparent 50%),
    radial-gradient(ellipse 30% 30% at 80% 70%, rgba(0,113,227,0.03) 0%, transparent 50%);
  pointer-events: none;
  animation: hero-ambient 14s ease-in-out infinite alternate;
}
@keyframes hero-ambient {
  0%   { transform: scale(1) translate(0, 0); }
  100% { transform: scale(1.06) translate(-12px, 12px); }
}

.hero-content {
  position: relative; z-index: 1; text-align: center;
  max-width: 800px; margin: 0 auto; padding: 0 24px;
}
.hero-eyebrow {
  display: inline-block; font-size: 0.8rem; font-weight: 500;
  letter-spacing: 0.15em; text-transform: uppercase;
  color: var(--text-secondary); margin-bottom: 20px;
}
.hero-name {
  font-size: clamp(3rem, 10vw, 5.5rem); font-weight: 600;
  letter-spacing: -0.03em; line-height: 1.05; margin-bottom: 20px;
  color: var(--text);
}
.hero-sub {
  font-size: clamp(1.1rem, 2.5vw, 1.375rem); font-weight: 400;
  color: var(--text-secondary); margin-bottom: 44px; line-height: 1.5;
}
.hero-sub span { color: var(--accent); }
.hero-actions {
  display: flex; flex-wrap: wrap; gap: 12px;
  justify-content: center; margin-bottom: 52px;
}

.btn {
  display: inline-flex; align-items: center; justify-content: center;
  gap: 8px; font-size: 0.875rem; font-weight: 500; height: 44px;
  padding: 0 24px; border-radius: 9999px; border: none; cursor: pointer;
  text-decoration: none; white-space: nowrap;
  transition: all var(--transition-spring); user-select: none;
}
.btn:hover { transform: scale(1.04); }
.btn:active { transform: scale(0.96); }
.btn-primary { background: var(--accent); color: #fff; }
.btn-primary:hover { background: var(--accent-hover); color: #fff; }
.btn-outline {
  background: transparent; color: var(--text);
  border: 1px solid var(--text-tertiary);
}
.btn-outline:hover { border-color: var(--text); }
.btn-icon {
  width: 44px; height: 44px; padding: 0; border-radius: 9999px;
  background: transparent; color: var(--text-secondary);
  border: 1px solid var(--text-tertiary);
}
.btn-icon:hover { color: var(--text); border-color: var(--text); }
.btn-icon svg { width: 17px; height: 17px; }
.hero-actions-group { display: inline-flex; align-items: center; gap: 10px; }

.hero-stats {
  display: flex; flex-wrap: wrap; gap: 8px; justify-content: center;
}
.hero-stat {
  display: flex; align-items: center; gap: 6px; padding: 6px 14px;
  background: var(--surface-2); border-radius: 9999px;
  font-size: 0.78rem; font-weight: 500; color: var(--text-secondary);
  transition: background var(--transition);
}
.hero-stat:hover { background: var(--border); }
.hero-stat strong { color: var(--text); font-weight: 600; }
.hero-stat--event {
  background: var(--accent-glow-strong);
  color: var(--accent);
}
.hero-stat--event:hover { background: var(--accent-glow); }
.hero-stat--event strong { color: var(--accent); }

/* Section Headers */
.section-label {
  display: block; font-size: 0.7rem; font-weight: 600;
  letter-spacing: 0.12em; text-transform: uppercase;
  color: var(--text-secondary); margin-bottom: 8px;
}
.section-title {
  font-size: clamp(1.5rem, 3.5vw, 2.25rem); font-weight: 600;
  letter-spacing: -0.025em; color: var(--text); line-height: 1.15;
  margin-bottom: 12px;
}
.section-intro {
  color: var(--text-secondary); font-size: 1.125rem;
  line-height: 1.7;
}
.section-header { margin-bottom: 56px; }

/* About */
.about-grid {
  display: grid; grid-template-columns: 240px 1fr; gap: 64px; align-items: start;
}
.about-photo {
  width: 100%; aspect-ratio: 1; object-fit: cover;
  border-radius: 16px; background: var(--surface-2);
}
.about-text p {
  color: var(--text-secondary); margin-bottom: 20px;
  font-size: 1.05rem; line-height: 1.8;
}
.about-text p:last-of-type { margin-bottom: 32px; }

.expertise-grid {
  display: flex; flex-wrap: wrap; gap: 8px; margin-top: 28px;
}
.pill {
  display: inline-flex; align-items: center; gap: 7px;
  padding: 8px 14px; background: var(--surface-2);
  border-radius: 9999px; font-size: 0.8rem; font-weight: 500;
  color: var(--text-secondary);
  transition: all var(--transition);
}
.pill:hover { color: var(--accent); background: var(--accent-glow); }
.pill svg { width: 14px; height: 14px; color: var(--accent); flex-shrink: 0; }

.tech-stack { margin-top: 16px; padding-top: 14px; border-top: 1px solid var(--border); }
.tech-label {
  display: block; font-size: 0.7rem; font-weight: 600;
  text-transform: uppercase; letter-spacing: 0.1em;
  color: var(--text-tertiary); margin-bottom: 8px;
}
.tech-grid { display: flex; flex-wrap: wrap; gap: 6px; }

/* Timeline */
.timeline { margin-top: 48px; padding-left: 20px; }
.timeline-item {
  position: relative; padding: 24px 0 24px 28px;
  border-left: 2px solid var(--border);
  transition: border-color var(--transition);
}
.timeline-item:first-child { padding-top: 0; }
.timeline-item:last-child { padding-bottom: 0; }
.timeline-item::before {
  content: ''; position: absolute; left: -5px; top: 28px;
  width: 12px; height: 12px; border-radius: 50%;
  background: var(--accent); border: 2px solid var(--bg);
  transition: background var(--transition), border-color var(--transition);
  z-index: 1;
}
.timeline-item:hover { border-left-color: var(--accent); }
.timeline-meta {
  display: flex; align-items: center; flex-wrap: wrap;
  gap: 12px; margin-bottom: 6px;
}
.timeline-period {
  font-size: 0.78rem; font-weight: 600; letter-spacing: 0.02em;
  color: var(--accent);
}
.timeline-company {
  font-size: 0.82rem; color: var(--text-tertiary); font-weight: 400;
}
.timeline-role {
  font-size: 1.1rem; font-weight: 600; color: var(--text);
  margin-bottom: 8px; letter-spacing: -0.01em;
}
.timeline-desc {
  font-size: 0.925rem; color: var(--text-secondary); line-height: 1.75;
}
.timeline-subsection-label {
  font-size: 0.75rem; font-weight: 600; letter-spacing: 0.1em;
  text-transform: uppercase; color: var(--text-tertiary);
  margin: 40px 0 24px 28px;
  padding-top: 20px;
  border-top: 1px solid var(--border);
}

/* Cert Grid */
.certs-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 20px;
}
.cert-card {
  background: var(--surface); border-radius: 16px;
  padding: 32px 20px 28px; cursor: pointer; text-align: center;
  transition: all var(--transition-spring);
  box-shadow: var(--shadow); user-select: none;
}
.cert-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-lg); }
.cert-card:active { transform: translateY(-1px); }
.cert-badge { width: 96px; height: 96px; object-fit: contain; margin: 0 auto 20px; border-radius: 8px; }
.cert-name { font-size: 0.875rem; font-weight: 600; color: var(--text); line-height: 1.4; margin-bottom: 12px; }
.cert-tags { display: flex; flex-wrap: wrap; gap: 6px; justify-content: center; }
.tag {
  font-size: 0.68rem; font-weight: 500; color: var(--text-secondary);
  background: var(--surface-2); padding: 3px 10px; border-radius: 9999px;
}

/* Modals */
.cert-dialog {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius-lg); color: var(--text);
  max-width: 540px; width: calc(100% - 48px); padding: 0;
  box-shadow: var(--shadow-lg);
  animation: modal-in 0.22s ease;
  position: fixed; top: 50%; left: 50%;
  transform: translate(-50%, -50%); margin: 0;
}
.cert-dialog::backdrop {
  background: rgba(0,0,0,0.7);
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
}
@keyframes modal-in {
  from { opacity: 0; transform: translate(-50%, calc(-50% + 14px)) scale(0.97); }
  to   { opacity: 1; transform: translate(-50%, -50%) scale(1); }
}
.dialog-inner { padding: 32px; }
.dialog-header {
  display: flex; align-items: flex-start; gap: 20px; margin-bottom: 24px;
}
.dialog-badge {
  width: 80px; height: 80px; object-fit: contain; flex-shrink: 0; border-radius: 8px;
}
.dialog-title-group { flex: 1; }
.dialog-title {
  font-size: 1.1rem; font-weight: 700; color: var(--text);
  line-height: 1.3; margin-bottom: 6px; letter-spacing: -0.01em;
}
.dialog-body {
  font-size: 0.9rem; color: var(--text-secondary);
  line-height: 1.75; margin-bottom: 20px;
}
.dialog-tags { display: flex; flex-wrap: wrap; gap: 6px; margin-bottom: 28px; }
.dialog-footer {
  display: flex; align-items: center; justify-content: space-between;
  padding-top: 20px; border-top: 1px solid var(--border); gap: 12px;
}
.btn-sm { height: 36px; padding: 0 18px; font-size: 0.85rem; }
.btn-ghost {
  background: transparent; color: var(--text-secondary);
  border: 1px solid var(--border);
}
.btn-ghost:hover {
  color: var(--text); border-color: var(--text-tertiary);
  background: var(--surface-2); transform: none;
}

/* Awards */
.awards-grid {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 20px;
}
.award-card {
  background: var(--surface); border-radius: 16px; padding: 32px;
  transition: all var(--transition-spring); box-shadow: var(--shadow);
}
.award-card:hover { transform: translateY(-2px); box-shadow: var(--shadow-lg); }
.award-year {
  display: inline-block; font-size: 0.72rem; font-weight: 600;
  letter-spacing: 0.06em; color: var(--accent); margin-bottom: 12px;
}
.award-title { font-size: 1rem; font-weight: 600; color: var(--text); margin-bottom: 8px; letter-spacing: -0.01em; line-height: 1.3; }
.award-desc { font-size: 0.9rem; color: var(--text-secondary); line-height: 1.7; }

/* Contact */
.s-contact { text-align: center; }
.s-contact .section-intro { margin: 0 auto 32px; }
.contact-email {
  display: inline-block; font-size: clamp(1.25rem, 3.5vw, 1.75rem);
  font-weight: 500; color: var(--text); letter-spacing: -0.02em;
  margin-bottom: 32px; text-decoration: none;
  border-bottom: 1px solid var(--accent); padding-bottom: 2px;
  transition: color var(--transition), border-color var(--transition);
}
.contact-email:hover { color: var(--accent); border-color: var(--accent); }
.contact-cta { display: flex; justify-content: center; }

/* Footer */
.site-footer {
  background: var(--surface); border-top: 1px solid var(--border);
  padding: 32px 0;
}
.site-footer .container {
  display: flex; flex-direction: column; align-items: center;
  text-align: center; gap: 16px;
}
.footer-copy {
  display: flex; flex-direction: column; gap: 3px;
  font-size: 0.8rem; color: var(--text-tertiary);
}
.footer-made { font-size: 0.72rem; color: var(--text-tertiary); opacity: 0.7; }
.footer-made-sep { color: var(--accent); opacity: 0.5; font-size: 0.6rem; margin: 0 4px; }
.footer-social { display: flex; gap: 12px; }
.footer-social a {
  display: flex; align-items: center; justify-content: center;
  width: 36px; height: 36px; border-radius: 9999px;
  border: 1px solid var(--border); color: var(--text-tertiary);
  transition: all var(--transition);
}
.footer-social a:hover { color: var(--text); border-color: var(--text-tertiary); }
.footer-social svg { width: 16px; height: 16px; fill: currentColor; }

/* Back to Top */
.back-to-top {
  position: fixed; bottom: 32px; right: 32px; z-index: 90;
  display: flex; align-items: center; justify-content: center;
  width: 40px; height: 40px; border-radius: 9999px;
  background: var(--surface); color: var(--text-secondary);
  border: 1px solid var(--border); cursor: pointer;
  opacity: 0; visibility: hidden; transform: translateY(8px);
  transition: all var(--transition); text-decoration: none;
  box-shadow: var(--shadow);
}
.back-to-top.is-visible { opacity: 1; visibility: visible; transform: translateY(0); }
.back-to-top:hover { border-color: var(--text-tertiary); color: var(--text); }
.back-to-top svg { width: 18px; height: 18px; }

/* Reveal Animations */
.js-loaded .reveal {
  opacity: 0; transform: translateY(24px);
  transition: opacity 0.6s cubic-bezier(0.25, 0.1, 0.25, 1),
              transform 0.6s cubic-bezier(0.25, 0.1, 0.25, 1);
}
.js-loaded .reveal.is-visible { opacity: 1; transform: translateY(0); }
.reveal-delay-1 { transition-delay: 0.1s; }
.reveal-delay-2 { transition-delay: 0.2s; }
.reveal-delay-3 { transition-delay: 0.3s; }
.reveal-delay-4 { transition-delay: 0.4s; }

/* Responsive */
@media (max-width: 768px) {
  .section { padding: 80px 0; }
  .nav-links {
    display: none;
    position: fixed; inset: var(--nav-height) 0 0 0;
    background: var(--bg);
    flex-direction: column; align-items: stretch;
    padding: 32px 24px; gap: 8px;
    border-top: 1px solid var(--border);
    z-index: 99; overflow-y: auto;
  }
  .nav-links.is-open { display: flex; }
  .nav-links a {
    display: block; width: 100%;
    font-size: 1.125rem; font-weight: 500;
    padding: 18px 24px; border-radius: 10px;
    color: var(--text-secondary); text-align: center;
  }
  .nav-links a:hover,
  .nav-links a.is-active { background: var(--surface-2); color: var(--text); }
  .nav-toggle { display: flex; }
  .about-grid { grid-template-columns: 1fr; gap: 40px; }
  .about-photo { max-width: 200px; }
  .about-grid > .reveal:first-child { text-align: center; }
  .certs-grid { grid-template-columns: repeat(auto-fill, minmax(160px, 1fr)); gap: 14px; }
  .awards-grid { grid-template-columns: 1fr; }
  .hero-actions { flex-direction: column; align-items: center; }
  .hero-actions > .btn { width: 100%; max-width: 280px; justify-content: center; }
  .hero-actions-group { justify-content: center; }
  .btn-icon { flex: 0 0 44px; width: 44px; }
  .timeline { padding-left: 10px; }
  .timeline-item { padding-left: 20px; }
  .timeline-item::before { width: 10px; height: 10px; left: -6px; top: 26px; }
  .timeline-item--edu::before { width: 7px; height: 7px; left: -5px; top: 28px; }
  .timeline-subsection-label { margin-left: 20px; }
}

@media (max-width: 480px) {
  .section { padding: 64px 0; }
  .hero-eyebrow { margin-bottom: 12px; }
  .hero-name { margin-bottom: 12px; }
  .hero-sub { margin-bottom: 28px; }
  .hero-actions { margin-bottom: 28px; gap: 10px; }
  .hero-actions-group { gap: 10px; }
  .hero-stats { gap: 6px; }
  .hero-stat { padding: 4px 12px; font-size: 0.72rem; }
  .certs-grid { grid-template-columns: repeat(2, 1fr); }
  .cert-card { padding: 24px 12px 20px; }
  .cert-badge { width: 80px; height: 80px; }
  .dialog-footer { flex-wrap: wrap; justify-content: center; }
}

@media (prefers-reduced-motion: reduce) {
  .js-loaded .reveal { opacity: 1 !important; transform: none !important; transition: none !important; }
  .s-hero::before { animation: none; }
  html { scroll-behavior: auto; }
}