/* =========================================================================
   Personal site — design system
   Palette: warm paper + near-black ink, one restrained indigo accent.
   Type:    Newsreader (display/prose) · IBM Plex Sans (UI) · IBM Plex Mono (meta)
   ========================================================================= */

:root {
  --paper:      #f7f6f3;
  --surface:    #ffffff;
  --ink:        #17171a;
  --ink-soft:   #2c2c31;
  --muted:      #6f6f76;
  --faint:      #a1a1a8;
  --hairline:   #e6e4dd;
  --accent:     #3b3fb0;
  --accent-ink: #2c2f8f;
  --accent-wash:#3b3fb012;

  --serif: "Newsreader", Georgia, "Times New Roman", serif;
  --sans:  "IBM Plex Sans", system-ui, -apple-system, sans-serif;
  --mono:  "IBM Plex Mono", ui-monospace, "SFMono-Regular", Menlo, monospace;

  --measure: 62ch;
  --page:    720px;    /* content column max */
  --wide:    980px;    /* nav / wide sections */

  --r: 10px;
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
}

/* ---------- reset-ish ---------- */
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 17px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
img, svg { max-width: 100%; display: block; }
a { color: inherit; }

/* subtle paper depth without shouting */
body::before {
  content: "";
  position: fixed; inset: 0;
  background:
    radial-gradient(1200px 600px at 82% -10%, #ffffff 0%, transparent 60%),
    radial-gradient(900px 500px at 0% 0%, #fbfaf7 0%, transparent 55%);
  pointer-events: none; z-index: 0;
}

/* ---------- layout ---------- */
.wrap { position: relative; z-index: 1; width: 100%; max-width: var(--wide);
  margin-inline: auto; padding-inline: 24px; }
.col  { max-width: var(--page); }
main  { padding-block: clamp(48px, 9vw, 104px); }

section + section { margin-top: clamp(52px, 8vw, 92px); }

/* ---------- eyebrow / labels ---------- */
.eyebrow {
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--accent-ink);
  margin: 0 0 18px;
}
.eyebrow::before { content: "→ "; opacity: 0.5; }

/* ---------- nav ---------- */
.nav {
  position: sticky; top: 0; z-index: 20;
  backdrop-filter: saturate(1.2) blur(8px);
  background: color-mix(in srgb, var(--paper) 82%, transparent);
  border-bottom: 1px solid var(--hairline);
}
.nav__inner {
  max-width: var(--wide); margin-inline: auto; padding: 15px 24px;
  display: flex; align-items: baseline; justify-content: space-between; gap: 16px;
}
.nav__brand {
  font-family: var(--serif); font-size: 1.06rem; font-weight: 500;
  letter-spacing: -0.01em; text-decoration: none; color: var(--ink);
  white-space: nowrap;
}
.nav__brand .dot { color: var(--accent); }
.nav__links { display: flex; align-items: baseline; gap: 22px; flex-wrap: wrap; justify-content: flex-end; }
.nav__links a {
  font-size: 0.86rem; text-decoration: none; color: var(--muted);
  transition: color 0.18s var(--ease); white-space: nowrap;
}
.nav__links a:hover, .nav__links a[aria-current="page"] { color: var(--ink); }
.nav__links a.ext::after { content: " ↗"; color: var(--faint); font-size: 0.85em; }
.nav__sep { width: 1px; height: 13px; background: var(--hairline); align-self: center; }
.nav__links .social { color: var(--faint); }
.nav__links .social:hover { color: var(--ink); }

/* ---------- hero ---------- */
.hero { position: relative; padding-top: 8px; }
.hero__grid {
  display: grid; grid-template-columns: 1fr; gap: 34px; align-items: start;
}
@media (min-width: 720px) {
  .hero__grid { grid-template-columns: 1fr auto; gap: 48px; }
}
.hero__name {
  font-family: var(--serif);
  font-weight: 400;
  font-size: clamp(2.6rem, 6.4vw, 4.4rem);
  line-height: 1.02;
  letter-spacing: -0.025em;
  margin: 0 0 20px;
}
.hero__lede {
  font-family: var(--serif);
  font-size: clamp(1.18rem, 2.4vw, 1.5rem);
  line-height: 1.45;
  color: var(--ink-soft);
  max-width: 30ch;
  margin: 0 0 26px;
}
.hero__lede em { font-style: italic; color: var(--ink); }

/* portrait / motif column */
.hero__aside { position: relative; width: min(240px, 60vw); justify-self: start; }
.portrait {
  width: 100%; aspect-ratio: 1; border-radius: 50%;
  border: 1px solid var(--hairline);
  object-fit: cover; background: var(--surface);
}
.motif {
  position: absolute; inset: -18% -18% auto auto; width: 136%;
  opacity: 0.16; pointer-events: none; z-index: -1;
}

/* inline link row */
.links { display: flex; flex-wrap: wrap; gap: 8px 20px; align-items: baseline;
  font-size: 0.92rem; }
.links a {
  text-decoration: none; color: var(--ink);
  border-bottom: 1px solid var(--hairline);
  padding-bottom: 1px; transition: border-color 0.18s var(--ease), color 0.18s var(--ease);
}
.links a:hover { color: var(--accent-ink); border-color: var(--accent); }
.links a::after { content: " ↗"; color: var(--faint); font-size: 0.82em; }
.links a.plain::after { content: none; }

/* ---------- prose ---------- */
.h2 {
  font-family: var(--serif); font-weight: 500;
  font-size: clamp(1.45rem, 3vw, 1.95rem);
  letter-spacing: -0.015em; line-height: 1.15; margin: 0 0 20px;
}
.prose { max-width: var(--measure); }
.prose p {
  font-family: var(--serif); font-size: 1.16rem; line-height: 1.62;
  color: var(--ink-soft); margin: 0 0 1.05em;
}
.prose p:last-child { margin-bottom: 0; }
.prose a { color: var(--accent-ink); text-decoration: underline;
  text-decoration-color: color-mix(in srgb, var(--accent) 40%, transparent);
  text-underline-offset: 3px; }
.prose a:hover { text-decoration-color: var(--accent); }

/* ---------- "building" card ---------- */
.card {
  background: var(--surface); border: 1px solid var(--hairline);
  border-radius: var(--r); padding: clamp(22px, 4vw, 34px);
}
.card__kicker {
  font-family: var(--mono); font-size: 0.72rem; letter-spacing: 0.14em;
  text-transform: uppercase; color: var(--muted); margin: 0 0 6px;
}
.card__title { font-family: var(--serif); font-weight: 500; font-size: 1.5rem;
  margin: 0 0 12px; letter-spacing: -0.01em; }
.card__title a { text-decoration: none; color: var(--ink); }
.card__title a:hover { color: var(--accent-ink); }
.pillars {
  list-style: none; margin: 22px 0 0; padding: 20px 0 0;
  border-top: 1px solid var(--hairline);
  display: grid; gap: 20px;
}
@media (min-width: 620px) { .pillars { grid-template-columns: repeat(3, 1fr); gap: 26px; } }
.pillars h4 { font-family: var(--sans); font-size: 0.82rem; font-weight: 600;
  letter-spacing: 0.02em; margin: 0 0 6px; color: var(--ink); }
.pillars .n { font-family: var(--mono); font-size: 0.72rem; color: var(--accent);
  display: block; margin-bottom: 8px; }
.pillars p { font-size: 0.9rem; line-height: 1.5; color: var(--muted); margin: 0; }

/* ---------- fact list (background) ---------- */
.facts { list-style: none; margin: 0; padding: 0; max-width: var(--measure); }
.facts li {
  display: grid; grid-template-columns: 92px 1fr; gap: 18px;
  padding: 13px 0; border-top: 1px solid var(--hairline); align-items: baseline;
}
.facts li:last-child { border-bottom: 1px solid var(--hairline); }
.facts .yr { font-family: var(--mono); font-size: 0.8rem; color: var(--muted); }
.facts .what { font-size: 0.98rem; color: var(--ink-soft); }
.facts .what b { font-weight: 600; color: var(--ink); }

/* ---------- publications ---------- */
.pubs { list-style: none; margin: 0; padding: 0; max-width: var(--measure); }
.pub {
  display: grid; grid-template-columns: 64px minmax(0, 1fr); gap: 14px;
  padding: 20px 0; border-top: 1px solid var(--hairline); align-items: start;
}
@media (min-width: 640px) {
  .pub { grid-template-columns: 88px minmax(0, 1fr); gap: 18px; }
}
.pubs .pub:last-child { border-bottom: 1px solid var(--hairline); }
.pub__thumb {
  width: 100%; aspect-ratio: 4 / 3; border-radius: 8px; object-fit: cover;
  border: 1px solid var(--hairline); background: var(--surface);
}
.pub__body { min-width: 0; }
.pub__title { font-family: var(--serif); font-weight: 500; font-size: 1.2rem;
  line-height: 1.25; letter-spacing: -0.01em; margin: 0 0 6px; }
.pub__title a { text-decoration: none; color: var(--ink);
  transition: color 0.18s var(--ease); }
.pub__title a:hover { color: var(--accent-ink); }
.pub__authors { font-size: 0.9rem; color: var(--muted); margin: 0 0 7px; line-height: 1.5; }
.pub__authors b { color: var(--ink); font-weight: 600; }
.pub__meta { font-family: var(--mono); font-size: 0.74rem; color: var(--faint);
  letter-spacing: 0.02em; display: flex; flex-wrap: wrap; gap: 5px 14px; align-items: baseline; }
.pub__meta .venue { color: var(--muted); }
.pub__meta a { color: var(--accent-ink); text-decoration: none; }
.pub__meta a:hover { text-decoration: underline; }
.pub__meta a::before { content: "["; color: var(--faint); }
.pub__meta a::after  { content: "]"; color: var(--faint); }
.pub--todo .pub__title { color: var(--faint); font-style: italic; }

/* ---------- writing list ---------- */
.year-head {
  font-family: var(--mono); font-size: 0.78rem; letter-spacing: 0.12em;
  color: var(--faint); margin: 0 0 6px; padding-top: 8px;
}
.entry {
  display: grid; grid-template-columns: 1fr; gap: 4px;
  padding: 22px 0; border-top: 1px solid var(--hairline);
  text-decoration: none; color: inherit; transition: transform 0.2s var(--ease);
}
.entry.has-thumb { grid-template-columns: 84px 1fr; column-gap: 16px; row-gap: 2px; align-items: start; }
@media (min-width: 640px) {
  .entry.has-thumb { grid-template-columns: 132px 1fr; column-gap: 26px; }
}
.entry:hover { transform: translateX(3px); }
.entry__thumb {
  width: 100%; aspect-ratio: 4 / 3; border-radius: 8px; object-fit: cover;
  border: 1px solid var(--hairline); background: var(--surface);
}
.entry__date { font-family: var(--mono); font-size: 0.74rem; color: var(--muted);
  letter-spacing: 0.02em; margin-bottom: 3px; }
.entry__title { font-family: var(--serif); font-weight: 500; font-size: 1.34rem;
  letter-spacing: -0.01em; line-height: 1.2; margin: 0 0 6px;
  transition: color 0.18s var(--ease); }
.entry:hover .entry__title { color: var(--accent-ink); }
.entry__blurb { font-size: 0.98rem; color: var(--muted); line-height: 1.5;
  max-width: 60ch; margin: 0; }
.entry__more { font-family: var(--mono); font-size: 0.72rem; color: var(--accent);
  margin-top: 8px; opacity: 0; transition: opacity 0.18s var(--ease); }
.entry:hover .entry__more { opacity: 1; }

/* ---------- article page ---------- */
.article { max-width: var(--measure); }
.article__meta { font-family: var(--mono); font-size: 0.76rem; color: var(--muted);
  letter-spacing: 0.04em; margin: 0 0 18px; }
.article__title { font-family: var(--serif); font-weight: 400;
  font-size: clamp(2rem, 4.6vw, 3rem); line-height: 1.08; letter-spacing: -0.02em;
  margin: 0 0 16px; }
.article__dek { font-family: var(--serif); font-style: italic; font-size: 1.28rem;
  line-height: 1.4; color: var(--muted); margin: 0 0 40px; }
.article .prose h3 { font-family: var(--serif); font-weight: 500; font-size: 1.4rem;
  letter-spacing: -0.01em; margin: 2em 0 0.6em; }
.article .prose blockquote {
  margin: 1.6em 0; padding: 4px 0 4px 22px; border-left: 2px solid var(--accent);
  font-style: italic; color: var(--ink); }
.article .prose blockquote p { font-size: 1.24rem; }
.prose figure { margin: 2em 0; }
.prose figure img { width: 100%; border: 1px solid var(--hairline); border-radius: var(--r);
  background: var(--surface); }
.prose figcaption { font-family: var(--sans); font-size: 0.84rem; color: var(--muted);
  line-height: 1.55; margin-top: 16px; }
.prose figure.diagram figcaption { margin-top: 18px; padding-top: 14px;
  border-top: 1px solid var(--hairline); }
.prose figcaption .fignum { color: var(--accent-ink); font-weight: 600; }
.prose .tbl-wrap { overflow-x: auto; margin: 1.9em 0; }
.prose table { width: 100%; border-collapse: collapse; font-family: var(--sans);
  font-size: 0.92rem; }
.prose caption { font-family: var(--mono); font-size: 0.74rem; color: var(--muted);
  text-align: left; letter-spacing: 0.02em; margin-bottom: 12px; caption-side: top; }
.prose th, .prose td { text-align: left; padding: 8px 16px 8px 0;
  border-bottom: 1px solid var(--hairline); white-space: nowrap; }
.prose thead th { border-bottom: 1px solid var(--ink-soft); font-weight: 600; }
.prose td.num, .prose th.num { font-family: var(--mono); text-align: right;
  font-variant-numeric: tabular-nums; }
.prose tbody tr:last-child td { border-bottom: 1px solid var(--ink-soft); }
.prose figure.diagram { background: var(--surface); border: 1px solid var(--hairline);
  border-radius: var(--r); padding: 28px 28px 18px; margin: 2.4em 0; }
.prose figure.diagram svg { width: 100%; height: auto; border: 0; background: none;
  display: block; margin-inline: auto; }
@media (max-width: 640px) { .prose figure.diagram { padding: 18px 16px 14px; } }
.prose .eqn { overflow-x: auto; overflow-y: hidden; margin: 1.4em 0; }
.prose .note { font-size: 0.94rem; color: var(--muted); border-left: 2px solid var(--hairline);
  padding-left: 16px; margin: 1.6em 0; }
/* pre-rendered LaTeX (SVG) */
.prose .matheq { display: inline-block; border: 0; background: none; margin: 0;
  max-width: 100%; }
.prose .matheq--display { display: block; margin: 1.2em auto; }
.prose .eqn { text-align: center; }
.prose .eqn table { text-align: left; }
/* pseudocode / algorithm card */
.prose .algo { background: var(--surface); border: 1px solid var(--hairline);
  border-left: 3px solid var(--accent); border-radius: var(--r);
  padding: 20px 26px 22px; margin: 2.4em 0; }
.prose .algo__title { font-family: var(--mono); font-size: 0.78rem; font-weight: 600;
  letter-spacing: 0.04em; color: var(--accent-ink); margin: 0 0 6px; }
.prose .algo__io { font-family: var(--mono); font-size: 0.82rem; color: var(--muted);
  margin: 0 0 16px; }
.prose .algo__io span { color: var(--faint); text-transform: uppercase;
  letter-spacing: 0.07em; font-size: 0.72rem; margin-right: 10px; }
.prose .algo__steps, .prose .algo__steps ol { margin: 0; padding-left: 1.6em; }
.prose .algo__steps > li { margin: 0.7em 0; padding-left: 0.2em; }
.prose .algo__steps ol { list-style: lower-alpha; margin-top: 0.5em; }
.prose .algo__steps ol > li { margin: 0.6em 0; }
.prose .algo li::marker { color: var(--faint); font-family: var(--mono); font-size: 0.85em; }
.prose .algo .matheq--display { margin: 0.55em 0; }
@media (max-width: 640px) { .prose .algo { padding: 16px 18px 18px; } }
/* subsection headings */
.article .prose h3.sub { font-family: var(--serif); font-weight: 500; font-size: 1.16rem;
  color: var(--ink-soft); letter-spacing: -0.01em; margin: 1.8em 0 0.5em; }
.prose h3, .prose h3.sub { scroll-margin-top: 84px; }
/* table of contents */
.prose .toc { background: var(--surface); border: 1px solid var(--hairline);
  border-radius: var(--r); padding: 18px 26px 20px; margin: 2.2em 0; }
.prose .toc__title { font-family: var(--mono); font-size: 0.74rem; letter-spacing: 0.08em;
  text-transform: uppercase; color: var(--muted); margin: 0 0 12px; }
.prose .toc ol { margin: 0; padding-left: 1.4em; }
.prose .toc ol > li { margin: 0.35em 0; }
.prose .toc ul { list-style: none; margin: 0.3em 0; padding-left: 0.3em; }
.prose .toc ul li { margin: 0.25em 0; font-size: 0.95em; }
.prose .toc ul li::before { content: "– "; color: var(--faint); }
.prose .toc a { text-decoration: none; color: var(--accent-ink); }
.prose .toc a:hover { text-decoration: underline; }
/* citation block */
.prose pre.cite { background: var(--surface); border: 1px solid var(--hairline);
  border-radius: var(--r); padding: 14px 18px; overflow-x: auto; font-family: var(--mono);
  font-size: 0.78rem; line-height: 1.55; color: var(--ink-soft); margin: 0.6em 0 0; }
.backlink { display: inline-block; margin-bottom: 40px; font-family: var(--mono);
  font-size: 0.76rem; color: var(--muted); text-decoration: none; letter-spacing: 0.04em; }
.backlink:hover { color: var(--accent-ink); }
.backlink::before { content: "← "; }

/* ---------- page heading ---------- */
.page-title { font-family: var(--serif); font-weight: 400;
  font-size: clamp(2.2rem, 5vw, 3.2rem); letter-spacing: -0.02em; line-height: 1.05;
  margin: 0 0 12px; }
.page-intro { color: var(--muted); font-size: 1.02rem; max-width: 54ch; margin: 0 0 44px; }

/* ---------- footer ---------- */
.foot {
  margin-top: clamp(64px, 10vw, 120px);
  border-top: 1px solid var(--hairline);
  padding: 30px 0 60px;
  display: flex; flex-wrap: wrap; gap: 12px 26px;
  align-items: baseline; justify-content: space-between;
}
.foot__links { display: flex; flex-wrap: wrap; gap: 20px; }
.foot a { font-size: 0.86rem; text-decoration: none; color: var(--muted);
  transition: color 0.18s var(--ease); }
.foot a:hover { color: var(--accent-ink); }
.foot small { font-family: var(--mono); font-size: 0.72rem; color: var(--faint);
  letter-spacing: 0.02em; }

/* ---------- accessibility ---------- */
:focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; border-radius: 3px; }
.skip { position: absolute; left: -9999px; top: 8px; background: var(--ink); color: var(--paper);
  padding: 8px 14px; border-radius: 6px; z-index: 50; }
.skip:focus { left: 24px; }

/* gentle load reveal */
@keyframes rise { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: none; } }
.reveal { animation: rise 0.7s var(--ease) both; }
.reveal:nth-child(2) { animation-delay: 0.06s; }
.reveal:nth-child(3) { animation-delay: 0.12s; }

@media (prefers-reduced-motion: reduce) {
  * { animation: none !important; transition: none !important; scroll-behavior: auto !important; }
}