/* ── Fonts ─────────────────────────────────────────────── */

@font-face {
  font-family: 'Inter';
  font-style: normal;
  font-weight: 400;
  font-display: swap;
  src: url('fonts/Inter-Regular.woff2') format('woff2');
}

@font-face {
  font-family: 'Inter';
  font-style: normal;
  font-weight: 500;
  font-display: swap;
  src: url('fonts/Inter-Medium.woff2') format('woff2');
}

@font-face {
  font-family: 'Inter';
  font-style: normal;
  font-weight: 600;
  font-display: swap;
  src: url('fonts/Inter-SemiBold.woff2') format('woff2');
}

@font-face {
  font-family: 'Inter';
  font-style: normal;
  font-weight: 700;
  font-display: swap;
  src: url('fonts/Inter-Bold.woff2') format('woff2');
}

/* ── Custom Properties ────────────────────────────────── */

:root {
  --max-width: 920px;
  --font: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --mono: ui-monospace, 'SF Mono', 'Cascadia Code', 'Consolas', monospace;
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
  --duration: 0.5s;
}

/* ── Dark theme (default) ──────────────────────────────── */

:root, [data-theme="dark"] {
  color-scheme: dark;
  --bg: #0c1016;
  --bg-soft: #111723;
  --panel: rgba(21, 29, 43, 0.65);
  --panel-solid: #151d2b;
  --text: #e8edf5;
  --muted: #8a95a8;
  --accent: #79d4ff;
  --accent-hover: #a3e2ff;
  --accent-soft: rgba(121, 212, 255, 0.1);
  --border: rgba(255, 255, 255, 0.08);
  --header-bg: rgba(12, 16, 22, 0.82);
  --footer-bg: rgba(12, 16, 22, 0.8);
  --accent-border: rgba(121, 212, 255, 0.2);
  --accent-border-strong: rgba(121, 212, 255, 0.3);
  --accent-focus: rgba(121, 212, 255, 0.4);
  --accent-ring: rgba(121, 212, 255, 0.08);
  --input-bg: rgba(255, 255, 255, 0.04);
  --tag-bg: rgba(255, 255, 255, 0.03);
  --shadow: rgba(0, 0, 0, 0.3);
  --hero-grad-1: rgba(121, 212, 255, 0.1);
  --hero-grad-2: rgba(115, 148, 255, 0.07);
  --success: #34d399;
  --success-bg: rgba(52, 211, 153, 0.1);
  --success-border: rgba(52, 211, 153, 0.25);
  --error: #f87171;
  --error-bg: rgba(248, 113, 113, 0.1);
  --error-border: rgba(248, 113, 113, 0.25);
  --form-embed-bg: #fff;
}

/* ── Light theme ───────────────────────────────────────── */

[data-theme="light"] {
  color-scheme: light;
  --bg: #fafbfc;
  --bg-soft: #f0f2f5;
  --panel: rgba(255, 255, 255, 0.7);
  --panel-solid: #ffffff;
  --text: #1a1f2e;
  --muted: #5f6b7a;
  --accent: #0284c7;
  --accent-hover: #0369a1;
  --accent-soft: rgba(2, 132, 199, 0.08);
  --border: rgba(0, 0, 0, 0.08);
  --header-bg: rgba(250, 251, 252, 0.82);
  --footer-bg: rgba(240, 242, 245, 0.85);
  --accent-border: rgba(2, 132, 199, 0.2);
  --accent-border-strong: rgba(2, 132, 199, 0.3);
  --accent-focus: rgba(2, 132, 199, 0.4);
  --accent-ring: rgba(2, 132, 199, 0.1);
  --input-bg: rgba(0, 0, 0, 0.025);
  --tag-bg: rgba(0, 0, 0, 0.03);
  --shadow: rgba(0, 0, 0, 0.08);
  --hero-grad-1: rgba(2, 132, 199, 0.06);
  --hero-grad-2: rgba(99, 102, 241, 0.04);
  --success: #059669;
  --success-bg: rgba(5, 150, 105, 0.08);
  --success-border: rgba(5, 150, 105, 0.2);
  --error: #dc2626;
  --error-bg: rgba(220, 38, 38, 0.06);
  --error-border: rgba(220, 38, 38, 0.2);
  --form-embed-bg: #fff;
}

@media (prefers-color-scheme: light) {
  :root:not([data-theme="dark"]) {
    color-scheme: light;
    --bg: #fafbfc;
    --bg-soft: #f0f2f5;
    --panel: rgba(255, 255, 255, 0.7);
    --panel-solid: #ffffff;
    --text: #1a1f2e;
    --muted: #5f6b7a;
    --accent: #0284c7;
    --accent-hover: #0369a1;
    --accent-soft: rgba(2, 132, 199, 0.08);
    --border: rgba(0, 0, 0, 0.08);
    --header-bg: rgba(250, 251, 252, 0.82);
    --footer-bg: rgba(240, 242, 245, 0.85);
    --accent-border: rgba(2, 132, 199, 0.2);
    --accent-border-strong: rgba(2, 132, 199, 0.3);
    --accent-focus: rgba(2, 132, 199, 0.4);
    --accent-ring: rgba(2, 132, 199, 0.1);
    --input-bg: rgba(0, 0, 0, 0.025);
    --tag-bg: rgba(0, 0, 0, 0.03);
    --shadow: rgba(0, 0, 0, 0.08);
    --hero-grad-1: rgba(2, 132, 199, 0.06);
    --hero-grad-2: rgba(99, 102, 241, 0.04);
    --success: #059669;
    --success-bg: rgba(5, 150, 105, 0.08);
    --success-border: rgba(5, 150, 105, 0.2);
    --error: #dc2626;
    --error-bg: rgba(220, 38, 38, 0.06);
    --error-border: rgba(220, 38, 38, 0.2);
    --form-embed-bg: #fff;
  }
}

/* ── Reset ────────────────────────────────────────────── */

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

body {
  min-height: 100vh;
  font-family: var(--font);
  font-size: 15px;
  line-height: 1.6;
  color: var(--text);
  background: var(--bg);
  display: flex;
  flex-direction: column;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--accent);
  text-decoration: none;
  transition: color 0.2s ease;
}

a:hover {
  color: var(--accent-hover);
}

/* ── Focus + Skip Link ────────────────────────────────── */

:where(a, button):focus-visible {
  outline: 2px solid var(--accent-focus);
  outline-offset: 3px;
}

.skip-link {
  position: absolute;
  left: 1rem;
  top: 0.85rem;
  padding: 0.55rem 0.85rem;
  border-radius: 999px;
  border: 1px solid var(--accent-border-strong);
  background: var(--panel-solid);
  color: var(--text);
  transform: translateY(-160%);
  transition: transform 0.2s var(--ease);
  z-index: 999;
}

.skip-link:focus {
  transform: translateY(0);
}

/* ── Layout ───────────────────────────────────────────── */

.container {
  width: min(var(--max-width), calc(100% - 2.5rem));
  margin-inline: auto;
}

main { flex: 1; }

#main { scroll-margin-top: 5rem; }

/* ── Header ───────────────────────────────────────────── */

.site-header {
  position: sticky;
  top: 0;
  z-index: 30;
  border-bottom: 1px solid var(--border);
  background: var(--header-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
}

.nav-shell {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.75rem 0;
}

.brand {
  color: var(--text);
  font-weight: 700;
  font-size: 0.95rem;
  letter-spacing: 0.02em;
}

.brand:hover { color: var(--text); }

.main-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.3rem;
}

.main-nav a {
  color: var(--muted);
  padding: 0.35rem 0.7rem;
  border-radius: 999px;
  border: 1px solid transparent;
  font-size: 0.875rem;
  font-weight: 500;
  transition: all 0.2s ease;
}

.main-nav a:hover {
  color: var(--text);
  background: var(--accent-soft);
  border-color: var(--accent-border);
}

.main-nav a.active {
  color: var(--text);
  background: var(--accent-soft);
  border-color: var(--accent-border-strong);
}

/* ── Hero ─────────────────────────────────────────────── */

.hero-wrap {
  position: relative;
  overflow: hidden;
}

.hero-gradient {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 800px 500px at 70% 20%, var(--hero-grad-1), transparent 60%),
    radial-gradient(ellipse 600px 400px at 20% 60%, var(--hero-grad-2), transparent 60%);
  animation: hero-shift 12s ease-in-out infinite alternate;
  pointer-events: none;
}

@keyframes hero-shift {
  0%   { opacity: 1; transform: translateX(0); }
  100% { opacity: 0.7; transform: translateX(30px) translateY(-10px); }
}

.hero {
  padding: 5rem 0 2.5rem;
}

.eyebrow {
  margin: 0 0 0.5rem;
  color: var(--accent);
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

h1 {
  margin: 0;
  font-size: clamp(2rem, 5vw, 3.2rem);
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: -0.02em;
}

h2 {
  margin: 0 0 0.75rem;
  font-size: 1.25rem;
  font-weight: 600;
  line-height: 1.25;
  letter-spacing: -0.01em;
}

h3 {
  margin: 0 0 0.3rem;
  font-size: 1rem;
  font-weight: 600;
  line-height: 1.3;
}

p { margin: 0 0 0.85rem; }

.tagline {
  margin: 0.75rem 0 0;
  color: var(--muted);
  font-size: 1.15rem;
  font-weight: 400;
  letter-spacing: -0.005em;
}

.lede {
  margin-top: 0.75rem;
  max-width: 60ch;
  color: var(--muted);
  font-size: 1rem;
}

.hero-actions {
  margin-top: 1.25rem;
}

/* ── Cards ────────────────────────────────────────────── */

.link-grid {
  margin-top: 2.5rem;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1rem;
}

.card {
  display: block;
  padding: 1.25rem;
  border-radius: 14px;
  border: 1px solid var(--border);
  background: var(--panel);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  color: var(--text);
  transition: transform 0.25s var(--ease), border-color 0.25s ease,
              box-shadow 0.25s ease;
}

.card:hover {
  transform: translateY(-3px);
  border-color: var(--accent-border-strong);
  box-shadow: 0 8px 30px var(--shadow);
}

.card-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  margin-bottom: 0.75rem;
  border-radius: 10px;
  background: var(--accent-soft);
  color: var(--accent);
  font-size: 1.1rem;
  font-weight: 700;
}

.card h3 { margin-bottom: 0.25rem; }

.card p {
  margin: 0;
  color: var(--muted);
  font-size: 0.9rem;
}

/* ── Sections ─────────────────────────────────────────── */

.section {
  padding: 0.5rem 0 3rem;
}

.stack {
  display: grid;
  gap: 1rem;
}

/* ── Panels ───────────────────────────────────────────── */

.panel {
  border: 1px solid var(--border);
  background: var(--panel);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  border-radius: 14px;
  padding: 1.25rem 1.5rem;
}

.panel p:last-child { margin-bottom: 0; }

.panel-intro {
  color: var(--muted);
  margin-bottom: 1.25rem;
}

.panel.panel-cta {
  text-align: center;
  padding: 2rem;
}

.panel.panel-cta h2 {
  margin-bottom: 0.5rem;
}

.panel.panel-cta p {
  color: var(--muted);
}

/* ── Timeline (education, experience) ─────────────────── */

.timeline {
  list-style: none;
  padding: 0;
  margin: 0;
  position: relative;
}

.timeline::before {
  content: '';
  position: absolute;
  left: 7px;
  top: 8px;
  bottom: 8px;
  width: 1px;
  background: var(--border);
}

.timeline li {
  padding-left: 2rem;
  padding-bottom: 1.25rem;
  position: relative;
}

.timeline li:last-child { padding-bottom: 0; }

.timeline li::before {
  content: '';
  position: absolute;
  left: 3px;
  top: 8px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--accent);
  border: 2px solid var(--bg);
  box-shadow: 0 0 0 1px var(--accent);
}

/* ── List ─────────────────────────────────────────────── */

.list-clean {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  gap: 1rem;
}

.list-clean li {
  border-top: 1px solid var(--border);
  padding-top: 1rem;
}

.list-clean li:first-child {
  border-top: none;
  padding-top: 0;
}

.list-clean p {
  margin: 0.3rem 0 0;
  color: var(--muted);
}

/* ── Meta ─────────────────────────────────────────────── */

.meta {
  color: var(--muted);
  font-size: 0.85rem;
  font-weight: 500;
}

/* ── Tags ─────────────────────────────────────────────── */

.tag-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
}

.tag-list.spaced {
  margin-bottom: 0.85rem;
}

.tag {
  border: 1px solid var(--border);
  color: var(--muted);
  background: var(--tag-bg);
  border-radius: 999px;
  padding: 0.22rem 0.6rem;
  font-size: 0.82rem;
  font-weight: 500;
  transition: border-color 0.2s ease, color 0.2s ease;
}

.tag:hover {
  border-color: var(--accent-border-strong);
  color: var(--text);
}

/* ── Sub-nav ──────────────────────────────────────────── */

.sub-nav {
  margin-top: 1rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
}

.sub-nav a {
  color: var(--muted);
  border: 1px solid var(--border);
  padding: 0.3rem 0.65rem;
  border-radius: 999px;
  font-size: 0.85rem;
  font-weight: 500;
  transition: all 0.2s ease;
}

.sub-nav a:hover {
  color: var(--text);
  border-color: var(--accent-border-strong);
  background: var(--accent-soft);
}

.sub-nav a.active {
  color: var(--text);
  border-color: var(--accent-border-strong);
  background: var(--accent-soft);
}

/* ── Publications ─────────────────────────────────────── */

.pub-list {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  gap: 0.75rem;
  counter-reset: pub;
}

.pub-list li {
  counter-increment: pub;
  padding-left: 1.75rem;
  position: relative;
  font-size: 0.9rem;
  line-height: 1.55;
  color: var(--muted);
}

.pub-list li::before {
  content: counter(pub) ".";
  position: absolute;
  left: 0;
  color: var(--accent);
  font-weight: 600;
  font-size: 0.85rem;
}

.pub-list .pub-title {
  color: var(--text);
  font-weight: 500;
}

.pub-list a {
  font-size: 0.82rem;
  word-break: break-all;
}

/* ── Awards ───────────────────────────────────────────── */

.awards-grid {
  display: grid;
  gap: 0.5rem;
}

.award-row {
  display: flex;
  gap: 0.75rem;
  align-items: baseline;
  font-size: 0.9rem;
}

.award-year {
  color: var(--accent);
  font-weight: 600;
  font-size: 0.82rem;
  min-width: 3.5rem;
  flex-shrink: 0;
}

.award-name {
  color: var(--text);
}

.award-inst {
  color: var(--muted);
  font-size: 0.82rem;
}

/* ── Contact Form ─────────────────────────────────────── */

.contact-form {
  display: grid;
  gap: 1rem;
}

.form-group {
  display: grid;
  gap: 0.35rem;
}

.form-group label {
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--text);
}

.form-group input,
.form-group textarea {
  font-family: var(--font);
  font-size: 0.9rem;
  padding: 0.65rem 0.85rem;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--input-bg);
  color: var(--text);
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
  outline: none;
}

.form-group input:focus,
.form-group textarea:focus {
  border-color: var(--accent-focus);
  box-shadow: 0 0 0 3px var(--accent-ring);
}

.form-group textarea {
  resize: vertical;
  min-height: 120px;
}

.form-group input::placeholder,
.form-group textarea::placeholder {
  color: var(--muted);
  opacity: 0.5;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.4rem;
  padding: 0.65rem 1.5rem;
  border: none;
  border-radius: 8px;
  background: var(--accent);
  color: var(--bg);
  font-family: var(--font);
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.2s ease, transform 0.15s ease;
}

.btn:hover {
  background: var(--accent-hover);
  transform: translateY(-1px);
  color: var(--bg);
}

.btn:active { transform: translateY(0); }

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none;
}

.btn-outline {
  background: transparent;
  border: 1px solid var(--accent);
  color: var(--accent);
}

.btn-outline:hover {
  background: var(--accent-soft);
  color: var(--accent-hover);
}

.form-status {
  padding: 0.75rem 1rem;
  border-radius: 8px;
  font-size: 0.9rem;
  display: none;
}

.form-status.success {
  display: block;
  background: var(--success-bg);
  border: 1px solid var(--success-border);
  color: var(--success);
}

.form-status.error {
  display: block;
  background: var(--error-bg);
  border: 1px solid var(--error-border);
  color: var(--error);
}

/* ── Google Form Embed ────────────────────────────────── */

.form-wrap {
  border: 1px solid var(--border);
  border-radius: 14px;
  overflow: hidden;
  background: var(--form-embed-bg);
}

.form-wrap iframe {
  width: 100%;
  min-height: 1142px;
  border: 0;
  display: block;
}

/* ── External Link Cards ──────────────────────────────── */

.link-card {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 1rem 1.25rem;
  border-radius: 14px;
  border: 1px solid var(--border);
  background: var(--panel);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  color: var(--text);
  transition: transform 0.25s var(--ease), border-color 0.25s ease;
}

.link-card:hover {
  transform: translateY(-2px);
  border-color: var(--accent-border-strong);
}

.link-card-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border-radius: 10px;
  background: var(--accent-soft);
  color: var(--accent);
  font-size: 1.3rem;
  flex-shrink: 0;
}

.link-card-icon svg {
  width: 22px;
  height: 22px;
  fill: currentColor;
}

.link-card-text h3 { margin-bottom: 0.1rem; }

.link-card-text p {
  margin: 0;
  color: var(--muted);
  font-size: 0.875rem;
}

/* ── Theme Toggle ────────────────────────────────────── */

.theme-toggle {
  appearance: none;
  border: 1px solid var(--border);
  background: var(--tag-bg);
  color: var(--muted);
  border-radius: 999px;
  width: 2rem;
  height: 2rem;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1rem;
  line-height: 1;
  cursor: pointer;
  transition: border-color 0.2s ease, color 0.2s ease;
  flex-shrink: 0;
}

.theme-toggle:hover {
  border-color: var(--accent-border);
  color: var(--text);
}

/* ── Scroll Reveal ────────────────────────────────────── */

[data-reveal] {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity var(--duration) var(--ease),
              transform var(--duration) var(--ease);
}

[data-reveal].revealed {
  opacity: 1;
  transform: translateY(0);
}

@media (prefers-reduced-motion: reduce) {
  .hero-gradient { animation: none; }

  [data-reveal] {
    transform: none;
    transition: none;
  }
}

/* ── Footer ───────────────────────────────────────────── */

.site-footer {
  margin-top: 3rem;
  border-top: 1px solid var(--border);
  background: var(--footer-bg);
}

.footer-row {
  padding: 1.25rem 0;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 0.75rem;
  flex-wrap: wrap;
}

.footer-row p {
  margin: 0;
  color: var(--muted);
  font-size: 0.85rem;
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.footer-links a {
  color: var(--muted);
  font-size: 0.85rem;
}

.footer-links a:hover { color: var(--text); }

.pgp-fingerprint {
  font-size: 0.75rem;
  color: var(--muted);
  opacity: 0.7;
}

.pgp-fingerprint code {
  font-family: 'SF Mono', Menlo, Consolas, monospace;
  font-size: 0.7rem;
  letter-spacing: 0.02em;
}

/* ── Responsive ───────────────────────────────────────── */

@media (max-width: 700px) {
  .nav-shell {
    align-items: flex-start;
    flex-direction: column;
    gap: 0.5rem;
    position: relative;
  }

  .theme-toggle {
    position: absolute;
    top: 0.75rem;
    right: 0;
  }

  .hero { padding: 3.5rem 0 2rem; }

  h1 { font-size: clamp(1.75rem, 6vw, 2.4rem); }

  .link-grid {
    grid-template-columns: 1fr;
  }

  .award-row {
    flex-direction: column;
    gap: 0.15rem;
  }

  .panel { padding: 1rem 1.15rem; }

  .panel.panel-cta { padding: 1.5rem; }
}

/* ── Article ──────────────────────────────────────────── */

.article .panel p {
  color: var(--text);
  opacity: 0.88;
}

.article .panel strong {
  opacity: 1;
}

@media (max-width: 400px) {
  .container {
    width: calc(100% - 1.5rem);
  }

  .main-nav a {
    padding: 0.3rem 0.5rem;
    font-size: 0.8rem;
  }
}