/* ── Custom Properties ─────────────────────────────────────── */
:root {
  --bg:          #070b0f;
  --surface:     #0d1318;
  --surface-2:   #131b24;
  --ink:         #e4ecf4;
  --ink-2:       #b0c2d4;
  --ink-3:       #728fa6;
  --accent:      #59bbbf;
  --accent-dim:  rgba(89,187,191,0.12);
  --border:      #182030;
  --font-sans:   'IBM Plex Sans', system-ui, sans-serif;
  --font-serif:  'Newsreader', Georgia, serif;
  --font-mono:   'IBM Plex Mono', monospace;
  --radius:      6px;
  --tr:          0.2s ease;
  --container:   1100px;
  --prose:       740px;
}

/* ── Reset ─────────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; font-size: 18px; }
body {
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font-sans);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}
a { color: var(--accent); text-decoration: none; transition: opacity var(--tr); }
a:hover { opacity: 0.72; }
img, video { max-width: 100%; height: auto; display: block; }

/* ── Layout ────────────────────────────────────────────────── */
.container {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 2rem;
}

/* ── Navigation ────────────────────────────────────────────── */
.nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  padding: 1.2rem 0;
  background: rgba(7,11,15,0.7);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid transparent;
  transition: border-color 0.3s, background 0.3s;
}
.nav.scrolled {
  border-bottom-color: var(--border);
  background: rgba(7,11,15,0.92);
}
.nav__inner { display: flex; align-items: center; justify-content: space-between; }
.nav__logo {
  font-family: var(--font-serif);
  font-size: 1.05rem;
  color: var(--ink);
}
.nav__logo:hover { opacity: 1; color: var(--ink); }
.nav__links { display: flex; gap: 2rem; list-style: none; }
.nav__links a { font-size: 0.9rem; color: var(--ink-2); letter-spacing: 0.02em; transition: color var(--tr); }
.nav__links a:hover { color: var(--ink); opacity: 1; }

/* ── Hero ──────────────────────────────────────────────────── */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  overflow: hidden;
}
.hero__canvas { position: absolute; inset: 0; width: 100%; height: 100%; }
.hero__overlay {
  position: absolute; inset: 0;
  background:
    radial-gradient(ellipse 65% 90% at 0% 55%, rgba(7,11,15,0.97) 25%, rgba(7,11,15,0.6) 55%, transparent 100%),
    linear-gradient(to bottom, rgba(7,11,15,0.35) 0%, transparent 25%, transparent 75%, rgba(7,11,15,0.7) 100%);
}
.hero__content {
  position: relative;
  z-index: 2;
  padding: 9rem 0 7rem;
  max-width: 580px;
  animation: fadeUp 0.9s ease 0.15s both;
}
.hero__eyebrow {
  font-family: var(--font-mono);
  font-size: 0.84rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 1.5rem;
}
.hero__name {
  font-family: var(--font-serif);
  font-size: clamp(3.2rem, 7vw, 5.8rem);
  font-weight: 300;
  line-height: 1.0;
  letter-spacing: -0.03em;
  color: var(--ink);
  margin-bottom: 1.75rem;
}
.hero__tagline {
  font-size: clamp(1rem, 1.8vw, 1.15rem);
  font-weight: 300;
  color: var(--ink-2);
  line-height: 1.7;
  margin-bottom: 2.5rem;
}
.hero__links { display: flex; gap: 0.875rem; flex-wrap: wrap; }

@keyframes fadeUp {
  from { opacity: 0; transform: translateY(18px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* ── Buttons ───────────────────────────────────────────────── */
.btn {
  display: inline-flex;
  align-items: center;
  padding: 0.6rem 1.35rem;
  border-radius: var(--radius);
  font-size: 0.85rem;
  font-weight: 500;
  transition: background var(--tr), color var(--tr), border-color var(--tr);
}
.btn--primary { background: var(--accent); color: #070b0f; border: 1px solid var(--accent); }
.btn--primary:hover { background: transparent; color: var(--accent); opacity: 1; }
.btn--ghost { background: transparent; color: var(--ink-2); border: 1px solid var(--border); }
.btn--ghost:hover { border-color: rgba(139,154,170,0.5); color: var(--ink); opacity: 1; }

/* ── Sections ──────────────────────────────────────────────── */
.section { padding: 6rem 0; }
.section__header { margin-bottom: 3rem; }
.section__kicker {
  font-family: var(--font-mono);
  font-size: 0.875rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 0.65rem;
}
.section__title {
  font-family: var(--font-serif);
  font-size: clamp(1.85rem, 3.5vw, 2.6rem);
  font-weight: 300;
  letter-spacing: -0.02em;
  color: var(--ink);
  line-height: 1.15;
}

/* ── Post Cards ────────────────────────────────────────────── */
.posts-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1px;
  background: var(--border);
  border: 1px solid var(--border);
  border-radius: calc(var(--radius) + 1px);
  overflow: hidden;
}
.post-card {
  background: var(--bg);
  padding: 2rem 1.875rem;
  display: flex;
  flex-direction: column;
  gap: 0.8rem;
  text-decoration: none;
  color: inherit;
  transition: background var(--tr);
}
.post-card:hover { background: var(--surface); opacity: 1; }
.post-card__meta { display: flex; align-items: center; gap: 0.8rem; flex-wrap: wrap; }
.post-card__category {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  padding: 0.22rem 0.6rem;
  border-radius: 3px;
  background: var(--accent-dim);
  color: var(--accent);
}
.post-card__date { font-family: var(--font-mono); font-size: 0.875rem; color: var(--ink-3); }
.post-card__title {
  font-family: var(--font-serif);
  font-size: 1.2rem;
  font-weight: 400;
  line-height: 1.3;
  letter-spacing: -0.01em;
  color: var(--ink);
}
.post-card__excerpt { font-size: 0.9rem; line-height: 1.7; color: var(--ink-2); flex: 1; }
.post-card__cta { font-size: 0.8rem; color: var(--accent); font-family: var(--font-mono); margin-top: 0.2rem; }

/* ── Publications ──────────────────────────────────────────── */
.publications-list { display: flex; flex-direction: column; }
.publication-item {
  padding: 2rem 0;
  border-bottom: 1px solid var(--border);
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 2rem;
  align-items: start;
}
.publication-item:first-child { border-top: 1px solid var(--border); }
.publication-item__title {
  font-family: var(--font-serif);
  font-size: 1.05rem;
  font-weight: 400;
  letter-spacing: -0.01em;
  color: var(--ink);
  line-height: 1.4;
  margin-bottom: 0.35rem;
}
.publication-item__authors { font-size: 0.875rem; color: var(--ink-2); margin-bottom: 0.2rem; }
.publication-item__venue { font-family: var(--font-mono); font-size: 0.875rem; color: var(--ink-3); letter-spacing: 0.03em; }
.publication-item__excerpt { font-size: 0.9rem; color: var(--ink-2); line-height: 1.65; margin-top: 0.7rem; }
.publication-item__links { display: flex; flex-direction: column; gap: 0.4rem; align-items: flex-end; flex-shrink: 0; padding-top: 0.15rem; }
.publication-link {
  font-family: var(--font-mono);
  font-size: 0.875rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--accent);
  padding: 0.28rem 0.6rem;
  border: 1px solid rgba(89,187,191,0.25);
  border-radius: 3px;
  transition: background var(--tr), border-color var(--tr);
  white-space: nowrap;
}
.publication-link:hover { background: var(--accent-dim); border-color: rgba(89,187,191,0.5); opacity: 1; }
.scholar-note { margin-top: 2rem; font-size: 0.85rem; color: var(--ink-3); }
.scholar-note a { color: var(--ink-2); border-bottom: 1px solid var(--border); padding-bottom: 1px; }
.scholar-note a:hover { color: var(--ink); border-color: var(--ink-2); opacity: 1; }

/* ── About ─────────────────────────────────────────────────── */
.about-grid {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 5rem;
  align-items: start;
}
.about-text p { font-size: 1rem; line-height: 1.8; color: var(--ink-2); margin-bottom: 1.25rem; }
.about-text p:last-child { margin-bottom: 0; }
.about-text strong { color: var(--ink); font-weight: 500; }
.about-topics { margin-top: 1.75rem; }
.about-topics__title {
  font-family: var(--font-mono);
  font-size: 0.875rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-3);
  margin-bottom: 0.9rem;
}
.about-topics__list { list-style: none; display: flex; flex-direction: column; gap: 0.55rem; }
.about-topics__list li { font-size: 0.9rem; color: var(--ink-2); display: flex; align-items: center; gap: 0.75rem; }
.about-topics__list li::before { content: ''; width: 4px; height: 4px; border-radius: 50%; background: var(--accent); flex-shrink: 0; }
.social-links { display: flex; flex-wrap: wrap; gap: 1rem 1.5rem; margin-top: 2rem; }
.social-link {
  font-family: var(--font-mono);
  font-size: 0.84rem;
  letter-spacing: 0.07em;
  text-transform: uppercase;
  color: var(--ink-3);
  border-bottom: 1px solid var(--ink-3);
  padding-bottom: 2px;
  transition: color var(--tr), border-color var(--tr);
}
.social-link:hover { color: var(--accent); border-color: var(--accent); opacity: 1; }
.about-credentials { display: flex; flex-direction: column; gap: 1.25rem; }
.credential {
  padding: 1.4rem 1.5rem;
  background: var(--surface-2);
  border-radius: var(--radius);
  border: 1px solid var(--border);
  transition: border-color var(--tr);
}
.credential:hover { border-color: rgba(89,187,191,0.25); }
.credential__school { font-family: var(--font-serif); font-size: 1rem; color: var(--ink); margin-bottom: 0.3rem; }
.credential__degree { font-size: 0.85rem; color: var(--ink-2); margin-bottom: 0.2rem; }
.credential__year { font-family: var(--font-mono); font-size: 0.875rem; color: var(--ink-3); letter-spacing: 0.04em; }

/* ── Footer ────────────────────────────────────────────────── */
.footer { padding: 2.5rem 0; border-top: 1px solid var(--border); }
.footer__inner { display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; gap: 1rem; }
.footer__copy { font-size: 0.875rem; color: var(--ink-3); font-family: var(--font-mono); }
.footer__links { display: flex; gap: 1.75rem; list-style: none; }
.footer__links a { font-size: 0.875rem; color: var(--ink-3); transition: color var(--tr); }
.footer__links a:hover { color: var(--ink-2); opacity: 1; }

hr.divider { border: none; border-top: 1px solid var(--border); }

/* ── Post Layout ───────────────────────────────────────────── */
.post-layout { padding-top: 5rem; }
.post-header {
  padding: 4rem 0 3.5rem;
  border-bottom: 1px solid var(--border);
}
.post-header__kicker {
  display: flex;
  align-items: center;
  margin-bottom: 1.75rem;
  font-family: var(--font-mono);
  font-size: 0.84rem;
  letter-spacing: 0.07em;
  text-transform: uppercase;
  color: var(--ink-3);
  gap: 0;
}
.post-header__category { color: var(--accent); margin-right: 1rem; }
.post-header__sep { margin-right: 1rem; }
.post-header__title {
  font-family: var(--font-serif);
  font-size: clamp(2rem, 5vw, 3.6rem);
  font-weight: 300;
  letter-spacing: -0.03em;
  line-height: 1.08;
  color: var(--ink);
  max-width: 860px;
}
.post-body { padding: 4rem 0 6rem; }

/* ── Post Prose ────────────────────────────────────────────── */
.post-content {
  max-width: var(--prose);
  font-size: 1.05rem;
  line-height: 1.82;
  color: var(--ink-2);
}
.post-content h2 {
  font-family: var(--font-serif);
  font-size: clamp(1.5rem, 2.8vw, 1.9rem);
  font-weight: 400;
  letter-spacing: -0.02em;
  color: var(--ink);
  line-height: 1.2;
  margin: 3.5rem 0 1.25rem;
}
.post-content h2:first-child { margin-top: 0; }
.post-content h3 {
  font-family: var(--font-serif);
  font-size: 1.25rem;
  font-weight: 400;
  color: var(--ink);
  margin: 2.25rem 0 0.75rem;
}
.post-content p { margin-bottom: 1.5rem; }
.post-content ul, .post-content ol { margin: 0 0 1.5rem 1.5rem; }
.post-content li { margin-bottom: 0.4rem; }
.post-content a { color: var(--ink-2); border-bottom: 1px solid rgba(139,154,170,0.3); padding-bottom: 1px; }
.post-content a:hover { color: var(--accent); border-bottom-color: var(--accent); opacity: 1; }
.post-content strong { font-weight: 600; color: var(--ink); }
.post-content em { font-style: italic; }

/* Figures */
.post-content figure { margin: 2.5rem 0; }
.post-content figure img,
.post-content figure video {
  border-radius: var(--radius);
  border: 1px solid var(--border);
  margin: 0 auto;
}
.post-content figcaption {
  font-size: 0.875rem;
  color: var(--ink-3);
  text-align: center;
  margin-top: 0.8rem;
  font-style: italic;
  line-height: 1.55;
}

/* Shiki code blocks */
.post-content pre.astro-code {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem 1.75rem;
  overflow-x: auto;
  margin: 2rem 0;
  font-size: 0.875rem;
  line-height: 1.75;
}
.post-content :not(pre) > code {
  font-family: var(--font-mono);
  font-size: 0.85em;
  background: var(--surface-2);
  padding: 0.15em 0.4em;
  border-radius: 3px;
  border: 1px solid var(--border);
  color: var(--accent);
}

/* KaTeX overrides */
.post-content .katex-display {
  margin: 2rem 0;
  overflow-x: auto;
  overflow-y: hidden;
}
.post-content .katex { font-size: 1.05em; }

/* Post nav */
.post-nav {
  max-width: var(--prose);
  margin-top: 4rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border);
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  flex-wrap: wrap;
}
.post-nav__back { font-size: 0.85rem; color: var(--ink-3); transition: color var(--tr); }
.post-nav__back:hover { color: var(--ink-2); opacity: 1; }
.post-nav__arrows { display: flex; gap: 1.5rem; }
.post-nav__link { font-size: 0.85rem; color: var(--ink-3); transition: color var(--tr); }
.post-nav__link:hover { color: var(--ink-2); opacity: 1; }
.post-nav__dir {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--ink-3);
  display: block;
  margin-bottom: 0.15rem;
}

/* ── Responsive ────────────────────────────────────────────── */
@media (max-width: 820px) {
  .posts-grid { grid-template-columns: 1fr; }
  .about-grid { grid-template-columns: 1fr; gap: 3rem; }
  .publication-item { grid-template-columns: 1fr; }
  .publication-item__links { flex-direction: row; align-items: flex-start; }
}
@media (max-width: 640px) {
  .container { padding: 0 1.25rem; }
  .nav__links { gap: 1.25rem; }
  .hero__content { padding: 7rem 0 5rem; }
  .section { padding: 4rem 0; }
  .footer__inner { flex-direction: column; align-items: flex-start; }
}
@media (max-width: 440px) {
  .nav__links { display: none; }
}