:root {
  --bg: #ffffff;
  --bg-alt: #f7f8fa;
  --surface: #ffffff;
  --text: #1f2933;
  --text-muted: #52606d;
  --border: #e4e7eb;
  --accent: #1d4ed8;
  --accent-soft: #eff4ff;
  --accent-strong: #1746b0;
  --shadow: 0 1px 3px rgba(31, 41, 51, .06), 0 1px 2px rgba(31, 41, 51, .04);
  --shadow-lg: 0 6px 24px rgba(31, 41, 51, .08);
  --radius: 8px;
  --radius-lg: 12px;
  --maxw: 1100px;
  --space-section: clamp(3.5rem, 8vw, 6rem);
  --font: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
}

@media (prefers-color-scheme: dark) {
  /* Light professional style stays light; dark not used. */
}

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

html { scroll-behavior: smooth; }

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

body {
  margin: 0;
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.6;
  color: var(--text);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

img, svg { display: block; max-width: 100%; }

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

h1, h2, h3, h4 { line-height: 1.25; font-weight: 600; margin: 0 0 .5em; }
h2 { font-size: clamp(1.6rem, 3vw, 2.1rem); }
h3 { font-size: 1.15rem; }
p { margin: 0 0 1em; }

.container { width: 100%; max-width: var(--maxw); margin: 0 auto; padding: 0 1.25rem; }

.icon { display: inline-block; vertical-align: middle; }

/* Skip link */
.skip-link {
  position: absolute; left: -9999px; top: 0; z-index: 100;
  background: var(--accent); color: #fff; padding: .6rem 1rem; border-radius: 0 0 6px 0;
}
.skip-link:focus { left: 0; }

/* Header */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: rgba(255,255,255,.85);
  backdrop-filter: saturate(180%) blur(10px);
  border-bottom: 1px solid var(--border);
}
.header-inner { display: flex; align-items: center; justify-content: space-between; height: 60px; }

.brand { display: inline-flex; align-items: center; gap: .5rem; font-weight: 700; color: var(--text); }
.brand:hover { text-decoration: none; }
.brand-mark {
  display: inline-grid; place-items: center;
  width: 32px; height: 32px; border-radius: var(--radius);
  background: var(--accent); color: #fff; font-size: .85rem; font-weight: 700; letter-spacing: .02em;
}

.site-nav ul { list-style: none; display: flex; align-items: center; gap: 1.5rem; margin: 0; padding: 0; }
.site-nav a { color: var(--text); font-weight: 500; font-size: .95rem; }
.site-nav a:hover { color: var(--accent); text-decoration: none; }
.nav-cta {
  background: var(--accent); color: #fff; padding: .5rem 1rem; border-radius: var(--radius);
}
.nav-cta:hover { background: var(--accent-strong); color: #fff; }

.nav-toggle { display: none; background: none; border: 1px solid var(--border); border-radius: var(--radius); padding: .45rem; cursor: pointer; }
.nav-toggle-bar { display: block; width: 20px; height: 2px; background: var(--text); margin: 4px 0; transition: .2s; }
.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(1) { transform: translateY(6px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(3) { transform: translateY(-6px) rotate(-45deg); }

/* Hero */
.hero { padding: clamp(3rem, 9vw, 6rem) 0 clamp(2.5rem, 7vw, 4.5rem); }
.hero-inner { max-width: 760px; }
.hero-eyebrow {
  text-transform: uppercase; letter-spacing: .12em; font-size: .8rem; font-weight: 600;
  color: var(--accent); margin: 0 0 1rem;
}
.hero-title { font-size: clamp(2.2rem, 6vw, 3.4rem); font-weight: 700; letter-spacing: -.02em; margin: 0 0 .8rem; }
.hero-tagline { font-size: clamp(1.05rem, 2.2vw, 1.25rem); color: var(--text-muted); max-width: 620px; margin: 0 0 1.5rem; }
.hero-location { display: inline-flex; align-items: center; gap: .4rem; color: var(--text-muted); font-size: .95rem; margin: 0 0 1.75rem; }
.hero-actions { display: flex; flex-wrap: wrap; gap: .75rem; }

.btn {
  display: inline-flex; align-items: center; justify-content: center;
  padding: .7rem 1.4rem; border-radius: var(--radius); font-weight: 600; font-size: .95rem;
  border: 1px solid transparent; transition: background .15s, border-color .15s, color .15s;
}
.btn:hover { text-decoration: none; }
.btn-primary { background: var(--accent); color: #fff; }
.btn-primary:hover { background: var(--accent-strong); color: #fff; }
.btn-ghost { border-color: var(--border); color: var(--text); background: var(--surface); }
.btn-ghost:hover { border-color: var(--accent); color: var(--accent); }

/* Sections */
.section { padding: var(--space-section) 0; }
.section-alt { background: var(--bg-alt); }
.section-title { margin-bottom: 2rem; }

/* About */
.about-content { display: grid; gap: 2.25rem; }
.prose { font-size: 1.08rem; max-width: 760px; }
.prose p { margin: 0; }
.about-grid { display: grid; gap: 2rem; grid-template-columns: 1fr; }
.about-block h3 { color: var(--text); margin-bottom: 1rem; }

.chip-list { list-style: none; display: flex; flex-wrap: wrap; gap: .5rem; padding: 0; margin: 0; }
.chip-list li {
  background: var(--accent-soft); color: var(--accent-strong);
  border: 1px solid #d8e3fb; border-radius: 999px; padding: .35rem .8rem; font-size: .88rem; font-weight: 500;
}

/* Timeline */
.timeline { list-style: none; margin: 0; padding: 0 0 1rem; position: relative; }
.timeline-item { position: relative; padding-left: 2.25rem; padding-bottom: 2rem; }
.timeline-item:last-child { padding-bottom: 0; }
.timeline-item::before {
  content: ""; position: absolute; left: .42rem; top: .55rem; bottom: -1.25rem; width: 2px; background: var(--border);
}
.timeline-item:last-child::before { display: none; }
.timeline-marker {
  position: absolute; left: 0; top: .35rem; width: 1rem; height: 1rem; border-radius: 50%;
  background: var(--accent); border: 3px solid var(--bg); box-shadow: 0 0 0 1px var(--border);
}
.section-alt .timeline-marker { border-color: var(--bg-alt); }
.timeline-period { display: inline-flex; align-items: center; gap: .5rem; font-size: .82rem; color: var(--text-muted); margin: 0 0 .35rem; }
.timeline-period .dot { display: none; }
.timeline-role { margin: 0 0 .2rem; }
.timeline-org { font-weight: 600; color: var(--accent-strong); margin: 0 0 .15rem; }
.timeline-place { color: var(--text-muted); font-size: .9rem; margin: 0; }
.timeline-summary { margin: .4rem 0 0; color: var(--text-muted); }
.timeline-note { color: var(--text-muted); font-size: .92rem; margin-top: 1.25rem; }

/* Skills */
.skills-grid { display: grid; gap: 1.5rem; grid-template-columns: 1fr; }
.skill-group {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius-lg);
  padding: 1.5rem; box-shadow: var(--shadow);
}
.skill-group h3 { margin-bottom: 1rem; font-size: 1rem; }
.skill-tags { list-style: none; display: flex; flex-wrap: wrap; gap: .5rem; padding: 0; margin: 0; }
.skill-tags li {
  background: var(--bg-alt); border: 1px solid var(--border); color: var(--text);
  border-radius: var(--radius); padding: .4rem .75rem; font-size: .88rem;
}

/* Education */
.edu-list { list-style: none; padding: 0; margin: 0; display: grid; gap: 1rem; }
.edu-list li {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius-lg);
  padding: 1.25rem 1.5rem; box-shadow: var(--shadow);
}
.edu-school { margin: 0 0 .25rem; }
.edu-period { color: var(--text-muted); font-size: .9rem; margin: 0; }

/* Contact */
.contact-section { background: var(--accent-soft); }
.contact-inner { max-width: 720px; }
.contact-lead { color: var(--text-muted); font-size: 1.05rem; margin-bottom: 1.75rem; }
.contact-links { list-style: none; display: flex; flex-wrap: wrap; gap: .75rem; padding: 0; margin: 0; }
.contact-links li a {
  display: inline-flex; align-items: center; gap: .6rem; padding: .7rem 1.1rem;
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  color: var(--text); font-weight: 500; box-shadow: var(--shadow);
}
.contact-links li a:hover { border-color: var(--accent); color: var(--accent); text-decoration: none; }
.contact-links li a [data-tbd] {}

/* Videos */
.videos-grid { display: grid; gap: 1.75rem; grid-template-columns: 1fr; }
.video-card {
  margin: 0; background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius-lg); overflow: hidden; box-shadow: var(--shadow);
  display: flex; flex-direction: column;
}
.video-frame { position: relative; width: 100%; aspect-ratio: 16 / 9; background: #000; }
.video-frame iframe { position: absolute; inset: 0; width: 100%; height: 100%; border: 0; }
.video-card figcaption { padding: 1.25rem 1.5rem; }
.video-card figcaption h3 { margin: 0 0 .4rem; }
.video-card figcaption p { color: var(--text-muted); margin: 0 0 .75rem; font-size: .95rem; }
.video-meta { font-size: .82rem; font-weight: 600; color: var(--accent); margin: 0 0 .5rem !important; letter-spacing: .02em; }
.video-link { font-size: .9rem; font-weight: 500; }

/* Footer */
.site-footer { border-top: 1px solid var(--border); padding: 1.5rem 0; }
.footer-inner { display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap; gap: .75rem; }
.footer-copy { color: var(--text-muted); font-size: .9rem; margin: 0; }
.footer-social { list-style: none; display: flex; gap: 1rem; padding: 0; margin: 0; }
.footer-social a { color: var(--text-muted); font-size: .9rem; }
.footer-social a:hover { color: var(--accent); }

/* Reveal animation */
.reveal { opacity: 0; transform: translateY(16px); transition: opacity .5s ease, transform .5s ease; }
.reveal.is-visible { opacity: 1; transform: none; }

/* Responsive */
@media (min-width: 640px) {
  .about-grid { grid-template-columns: 1fr 1fr; }
  .skills-grid { grid-template-columns: 1fr 1fr; }
  .videos-grid { grid-template-columns: 1fr 1fr; }
}

@media (min-width: 1024px) {
  .skills-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 767px) {
  .nav-toggle { display: inline-flex; flex-direction: column; justify-content: center; }
  .site-nav {
    position: fixed; inset: 60px 0 auto 0; background: var(--bg);
    border-bottom: 1px solid var(--border); padding: 1rem 1.25rem 1.5rem;
    transform: translateY(-120%); transition: transform .25s ease; box-shadow: var(--shadow-lg);
  }
  .site-nav.open { transform: translateY(0); }
  .site-nav ul { flex-direction: column; align-items: stretch; gap: .25rem; }
  .site-nav a { display: block; padding: .7rem .5rem; border-radius: var(--radius); }
  .site-nav a:hover { background: var(--bg-alt); }
  .nav-cta { text-align: center; }
  .footer-inner { justify-content: center; text-align: center; }
}

:focus-visible { outline: 3px solid var(--accent); outline-offset: 2px; border-radius: 4px; }