/* Learn · learn.scuai.cn
   World: commutative diagram. Four topics are objects; arrows are the course.
   Hand-edited, no build step. */

:root {
  --paper: #f5f6f8;
  --paper-2: #eceef2;
  --ink: #15171e;
  --ink-2: #474c59;
  --rule: #c9cdd6;
  --rule-strong: #15171e;

  --alg: #2b3fd6;
  --infra: #0a7a6c;
  --api: #f0a818;
  --api-ink: #6b4500;
  --api-tint: #fdf1d6;
  --agent: #d93a22;

  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB",
    "Microsoft YaHei", "Noto Sans SC", "Noto Sans CJK SC", sans-serif;
  --math: "Latin Modern Roman", "STIX Two Text", "Cambria", "Times New Roman", "Songti SC", serif;
  --mono: ui-monospace, "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;

  --wrap: 1180px;
  --gutter: clamp(20px, 4vw, 48px);
  --shaft: 2px;
  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
}

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

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 17px;
  line-height: 1.8;
  letter-spacing: 0.01em;
  text-rendering: optimizeLegibility;
}

a { color: inherit; text-decoration-thickness: 1px; text-underline-offset: 0.22em; }
a:hover { text-decoration-thickness: 2px; }
:focus-visible { outline: 3px solid var(--alg); outline-offset: 3px; }

h1, h2, h3 { line-height: 1.3; text-wrap: balance; margin: 0; }
p { margin: 0 0 1em; }
img, svg { max-width: 100%; }

.wrap { max-width: var(--wrap); margin: 0 auto; padding: 0 var(--gutter); }

.cat { font-family: var(--math); font-weight: 700; font-style: normal; letter-spacing: 0; }
.var { font-family: var(--math); font-style: italic; letter-spacing: 0; }

.skip { position: absolute; left: -999px; top: 8px; background: var(--ink); color: #fff; padding: 6px 12px; z-index: 10; }
.skip:focus { left: 8px; }

/* ---------- Header ---------- */

.site-head { border-bottom: 1px solid var(--rule); }
.site-head .wrap {
  display: flex; align-items: center; justify-content: space-between; gap: 8px 24px;
  min-height: 64px; flex-wrap: wrap; padding-top: 8px; padding-bottom: 8px;
}
.brand {
  display: inline-flex; align-items: center; gap: 10px;
  font-weight: 800; font-size: 20px; text-decoration: none; letter-spacing: 0;
}
.brand .mark { width: 28px; height: 28px; flex: none; }
.brand small { font-weight: 400; font-size: 13px; color: var(--ink-2); }
.site-nav ul { display: flex; gap: clamp(16px, 2.4vw, 32px); list-style: none; margin: 0; padding: 0; flex-wrap: wrap; }
.site-nav a { text-decoration: none; font-size: 15px; padding: 6px 0; border-bottom: 2px solid transparent; }
.site-nav a:hover, .site-nav a[aria-current="page"] { border-bottom-color: currentColor; }

/* ---------- Footer ---------- */

.site-foot { margin-top: clamp(64px, 10vw, 128px); border-top: 1px solid var(--rule-strong); font-size: 14px; color: var(--ink-2); }
.site-foot .wrap { display: flex; justify-content: space-between; gap: 16px 32px; flex-wrap: wrap; padding-top: 28px; padding-bottom: 40px; }
.site-foot p { margin: 0; }
.site-foot .eq { font-family: var(--math); font-size: 16px; color: var(--ink); }
.site-foot .filings { display: flex; align-items: center; gap: 12px 24px; flex-wrap: wrap; width: 100%; }
.site-foot .filings a { display: inline-flex; align-items: center; gap: 5px; min-height: 20px; line-height: 20px; text-decoration: none; white-space: nowrap; }
.site-foot .filings a:hover { text-decoration: underline; }
.site-foot .filings img { width: 20px; height: 20px; flex: none; }

/* ---------- Home: thesis + diagram ---------- */

.thesis { padding-top: clamp(36px, 6vw, 72px); }
.thesis h1 { font-size: clamp(2rem, 4.6vw, 3.6rem); font-weight: 800; letter-spacing: -0.02em; max-width: 16em; }
.thesis .sub { margin-top: 10px; font-size: clamp(1.25rem, 2.2vw, 1.75rem); font-weight: 700; }
.thesis { display: grid; grid-template-columns: 1fr; gap: 36px 64px; }
.thesis .lede { margin-top: 14px; font-size: clamp(1rem, 1.4vw, 1.15rem); color: var(--ink-2); max-width: 36em; }

.cd {
  --gap-col: clamp(110px, 13vw, 200px);
  --gap-row: clamp(100px, 11vw, 150px);
  margin-top: clamp(28px, 4vw, 48px);
  display: grid;
  grid-template-columns: 1fr;
  grid-template-areas: "alg" "f" "infra" "g" "api" "h" "agent";
  position: relative;
  padding-left: 52px; /* room for the dashed composite on phones */
}

.obj {
  position: relative;
  display: flex; flex-direction: column; justify-content: space-between; gap: 18px;
  min-height: 172px;
  padding: clamp(18px, 2.2vw, 28px);
  text-decoration: none;
  color: #fff;
  transition: transform 0.5s var(--ease-out), box-shadow 0.5s var(--ease-out);
}
.obj:hover { transform: translateY(-3px); box-shadow: 0 14px 30px -18px rgba(21, 23, 30, 0.55); }
.obj h2 { font-size: clamp(1.45rem, 2.5vw, 2.25rem); font-weight: 800; letter-spacing: -0.01em; padding-right: 2.8em; }
.nb { white-space: nowrap; }
.obj p { margin: 8px 0 0; font-size: 15px; line-height: 1.6; max-width: 22em; }
.obj .cat { position: absolute; top: clamp(14px, 1.8vw, 22px); right: clamp(16px, 2vw, 26px); font-size: clamp(1.4rem, 2.4vw, 2.1rem); line-height: 1; }
.obj .go { font-size: 14px; font-weight: 600; display: inline-flex; gap: 8px; align-items: center; }
.obj .go::after { content: "→"; transition: transform 0.4s var(--ease-out); }
.obj:hover .go::after { transform: translateX(4px); }

.obj-alg { grid-area: alg; background: var(--alg); }
.obj-infra { grid-area: infra; background: var(--infra); }
.obj-api { grid-area: api; background: var(--api); color: var(--ink); }
.obj-agent { grid-area: agent; background: var(--agent); }

/* Arrows: mobile-first, all vertical, pointing down */
.arr { position: relative; min-height: 84px; display: flex; align-items: center; color: var(--ink); transition: color 0.3s var(--ease-out); }
.arr-f { grid-area: f; } .arr-g { grid-area: g; } .arr-h { grid-area: h; }
.shaft { position: absolute; left: 28px; top: 10px; bottom: 10px; width: var(--shaft); background: currentColor; }
.shaft::after {
  content: ""; position: absolute; left: 50%; bottom: -2px; width: 14px; height: 12px;
  transform: translateX(-50%); background: currentColor; clip-path: polygon(0 0, 100% 0, 50% 100%);
}
.lbl { margin-left: 52px; font-size: 15px; line-height: 1.5; padding: 2px 0; }
.lbl .var { font-size: 1.35em; margin-right: 6px; }
.lbl small { display: block; color: var(--ink-2); font-size: 13px; }

/* The composite arrow learn = h∘g∘f, dashed */
.arr-learn { position: absolute; left: 0; top: 0; bottom: 0; width: 44px; min-height: 0; }
.arr-learn .shaft {
  left: 14px; top: 40px; bottom: 40px; width: 0; background: none;
  border-left: var(--shaft) dashed currentColor;
}
.arr-learn .shaft::after { left: -1px; bottom: -4px; transform: translateX(-50%); }
.arr-learn .lbl {
  position: absolute; top: 50%; left: 24px; margin: 0; background: var(--paper);
  writing-mode: vertical-rl; transform: translateY(-50%);
  font-family: var(--math); font-size: 17px; white-space: nowrap; padding: 8px 0;
}

.cd-note { margin-top: 22px; font-size: 15px; color: var(--ink-2); max-width: 46em; }
.cd-note .var, .cd-note .cat { color: var(--ink); }

/* Diagram chase: shafts draw once, in order */
@media (prefers-reduced-motion: no-preference) {
  .cd .shaft { animation: draw-v 0.7s var(--ease-out) both; }
  .cd .arr-f .shaft { animation-delay: 0.15s; }
  .cd .arr-g .shaft { animation-delay: 0.6s; }
  .cd .arr-h .shaft { animation-delay: 1.05s; }
  .cd .arr-learn .shaft { animation-delay: 1.6s; animation-duration: 1s; }
}
@keyframes draw-v { from { clip-path: inset(-20px -20px 100% -20px); } to { clip-path: inset(-20px -20px -20px -20px); } }
@keyframes draw-h { from { clip-path: inset(-20px 100% -20px -20px); } to { clip-path: inset(-20px -20px -20px -20px); } }

/* Hovering an object lights the path that reaches it */
.cd:has(.obj-infra:hover) .arr-f,
.cd:has(.obj-api:hover) :is(.arr-f, .arr-g),
.cd:has(.obj-agent:hover) :is(.arr-f, .arr-g, .arr-h, .arr-learn) { color: var(--alg); }

@media (min-width: 880px) {
  .cd {
    padding-left: 0;
    grid-template-columns: minmax(0, 1fr) var(--gap-col) minmax(0, 1fr);
    grid-template-rows: auto var(--gap-row) auto;
    grid-template-areas:
      "alg   f   infra"
      "learn .   g"
      "agent h   api";
  }
  .obj { min-height: clamp(220px, 22vw, 290px); }

  .arr { min-height: 0; justify-content: center; }
  .arr-f .shaft, .arr-h .shaft {
    left: 14px; right: 14px; top: 50%; bottom: auto; width: auto; height: var(--shaft);
  }
  .arr-f .shaft::after, .arr-h .shaft::after {
    left: auto; right: -2px; bottom: auto; top: 50%; width: 12px; height: 14px;
    transform: translateY(-50%); clip-path: polygon(0 0, 100% 50%, 0 100%);
  }
  .arr-h .shaft { transform: scaleX(-1); }
  .arr-f .lbl, .arr-h .lbl { margin: 0; position: absolute; left: 50%; transform: translateX(-50%); text-align: center; white-space: nowrap; }
  .arr-f .lbl { bottom: calc(50% + 10px); }
  .arr-h .lbl { top: calc(50% + 10px); }
  .arr-g { justify-content: flex-start; }
  .arr-g .shaft { left: 50%; margin-left: -1px; }
  .arr-g .lbl { margin-left: calc(50% + 18px); }

  .arr-learn { position: relative; grid-area: learn; width: auto; display: flex; align-items: center; }
  .arr-learn .shaft { left: 50%; top: 10px; bottom: 10px; }
  .arr-learn .lbl {
    position: static; transform: none; writing-mode: horizontal-tb;
    margin-left: auto; margin-right: calc(50% + 18px); text-align: right; background: none;
  }

  @media (prefers-reduced-motion: no-preference) {
    .cd .arr-f .shaft, .cd .arr-h .shaft { animation-name: draw-h; }
  }
}

/* ---------- Home: topic index ---------- */

.section { margin-top: clamp(72px, 10vw, 128px); }
.section-head { display: flex; justify-content: space-between; align-items: baseline; gap: 16px; flex-wrap: wrap; border-bottom: 1px solid var(--rule-strong); padding-bottom: 14px; }
.section-head h2 { font-size: clamp(1.5rem, 2.6vw, 2.1rem); font-weight: 800; letter-spacing: -0.01em; }
.section-head a { font-size: 15px; }

.topics { list-style: none; margin: 0; padding: 0; }
.topic {
  display: grid; grid-template-columns: 1fr; gap: 14px 40px;
  padding: 32px 0; border-bottom: 1px solid var(--rule);
}
.topic .sig { display: flex; align-items: center; gap: 14px; }
.topic .chip { min-width: 56px; height: 44px; padding: 0 8px; flex: none; display: grid; place-items: center; font-family: var(--math); font-weight: 700; color: #fff; font-size: 15px; }
.topic h3 { font-size: clamp(1.25rem, 2vw, 1.6rem); font-weight: 800; }
.topic h3 a { text-decoration: none; }
.topic h3 a:hover { text-decoration: underline; }
.topic .motto { font-size: 18px; font-weight: 700; margin-bottom: 6px; }
.topic .body p { color: var(--ink-2); max-width: 38em; }
.topic .links { display: flex; flex-wrap: wrap; gap: 8px 22px; font-size: 15px; margin-top: 4px; }
@media (min-width: 880px) { .topic { grid-template-columns: 300px 1fr; } }

.c-alg { background: var(--alg); } .c-infra { background: var(--infra); }
.c-api { background: var(--api); } .c-agent { background: var(--agent); }
.chip.c-api { color: var(--ink); }

.status { font-size: 13px; color: var(--ink-2); white-space: nowrap; }
.placeholder-note {
  font-size: 13px; color: var(--ink-2); border: 1px dashed var(--rule); padding: 10px 14px; margin: 18px 0 0; max-width: 46em;
}

/* Updates list */
.updates { list-style: none; margin: 0; padding: 0; }
.updates li { display: grid; grid-template-columns: 1fr; gap: 4px 28px; padding: 18px 0; border-bottom: 1px solid var(--rule); }
.updates .kind { font-size: 14px; color: var(--ink-2); }
.updates a { font-weight: 700; font-size: 17px; }
@media (min-width: 720px) { .updates li { grid-template-columns: 140px 1fr auto; align-items: baseline; } }

.about-strip { display: grid; gap: 24px; grid-template-columns: 1fr; align-items: start; margin-top: 28px; }
.about-strip p { max-width: 38em; color: var(--ink-2); }
.about-strip .eq { font-family: var(--math); font-size: clamp(1.3rem, 2.4vw, 1.9rem); line-height: 1.4; margin: 0; }
@media (min-width: 880px) { .about-strip { grid-template-columns: 1fr 1fr; } }

/* ---------- Topic page ---------- */

.band { color: #fff; padding: clamp(40px, 7vw, 88px) 0 clamp(36px, 5vw, 64px); }
.band.c-api { color: var(--ink); }
.band .crumbs { font-size: 14px; margin-bottom: 18px; }
.band .crumbs a { text-decoration: none; } .band .crumbs a:hover { text-decoration: underline; }
.band h1 { font-size: clamp(2.2rem, 5.4vw, 4.2rem); font-weight: 800; letter-spacing: -0.02em; max-width: 14em; }
.band .cat-big { font-family: var(--math); font-weight: 700; font-size: 0.6em; margin-left: 0.4em; white-space: nowrap; }
.band .motto { margin-top: 14px; font-size: clamp(1.1rem, 1.8vw, 1.4rem); font-weight: 700; max-width: 30em; }
.band .desc { margin-top: 10px; max-width: 38em; }

/* Position in the chain */
.chain { display: flex; align-items: center; flex-wrap: wrap; gap: 8px 0; margin-top: 30px; font-size: 14px; }
.chain a, .chain .here { display: inline-flex; align-items: center; gap: 8px; text-decoration: none; padding: 5px 10px; border: 1px solid currentColor; }
.chain .here { background: #fff; color: var(--ink); border-color: #fff; font-weight: 700; }
.band.c-api .chain .here { background: var(--ink); color: #fff; border-color: var(--ink); }
.chain a:hover { text-decoration: underline; }
.chain .cat { font-size: 15px; }
.chain .to { padding: 0 10px; font-family: var(--math); font-style: italic; white-space: nowrap; }
.chain .to::after { content: " \2192"; font-style: normal; }

.columns { display: grid; gap: 48px; grid-template-columns: 1fr; margin-top: clamp(48px, 7vw, 80px); }
@media (min-width: 960px) { .columns { grid-template-columns: 1.3fr 1fr; gap: 72px; } }
.columns h2 { font-size: 1.35rem; font-weight: 800; border-bottom: 1px solid var(--rule-strong); padding-bottom: 10px; margin-bottom: 8px; }

.book-entry { display: grid; grid-template-columns: 104px 1fr; gap: 22px; padding: 22px 0; border-bottom: 1px solid var(--rule); }
.book-entry .spine { aspect-ratio: 3 / 4; padding: 10px; color: #fff; display: flex; flex-direction: column; justify-content: space-between; font-size: 12px; line-height: 1.35; font-weight: 700; text-decoration: none; }
.book-entry .spine.c-api { color: var(--ink); }
.book-entry .spine .cat { font-size: 16px; }
.book-entry h3 { font-size: 1.2rem; font-weight: 800; }
.book-entry h3 a { text-decoration: none; } .book-entry h3 a:hover { text-decoration: underline; }
.book-entry p { color: var(--ink-2); margin: 6px 0 8px; font-size: 15px; }

.plain-list { list-style: none; margin: 0; padding: 0; }
.plain-list li { padding: 14px 0; border-bottom: 1px solid var(--rule); display: flex; justify-content: space-between; gap: 4px 16px; align-items: baseline; flex-wrap: wrap; }
.plain-list li a { font-weight: 700; }
.plain-list li .no-link { font-weight: 700; color: var(--ink-2); }
.muted { color: var(--ink-2); }

/* ---------- Book cover + TOC ---------- */

.book-hero { display: grid; gap: 40px; grid-template-columns: 1fr; padding-top: clamp(36px, 6vw, 72px); align-items: end; }
@media (min-width: 880px) { .book-hero { grid-template-columns: 320px 1fr; gap: 64px; } }
.cover {
  aspect-ratio: 3 / 4; background: var(--infra); color: #fff; padding: 26px; position: relative;
  display: flex; flex-direction: column; justify-content: flex-end; gap: 14px; max-width: 320px;
  box-shadow: 0 24px 40px -28px rgba(10, 60, 54, 0.8);
}
.cover .t { font-size: 28px; font-weight: 800; line-height: 1.25; }
.cover .a { font-size: 14px; }
.cover svg { position: absolute; left: 26px; top: 26px; width: 120px; height: 120px; }
.crumbs-top { font-size: 14px; color: var(--ink-2); margin-bottom: 14px; }
.crumbs-top a { text-decoration: none; } .crumbs-top a:hover { text-decoration: underline; }
.book-hero h1 { font-size: clamp(2rem, 4.4vw, 3.3rem); font-weight: 800; letter-spacing: -0.02em; }
.book-hero .motto { font-size: 1.2rem; font-weight: 700; margin: 12px 0 10px; }
.book-hero p { color: var(--ink-2); max-width: 36em; }
.actions { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 18px; }
.btn {
  display: inline-flex; align-items: center; gap: 10px; padding: 11px 20px; font-size: 15px; font-weight: 700;
  text-decoration: none; border: 2px solid var(--ink); background: var(--ink); color: #fff;
  transition: background 0.3s var(--ease-out), color 0.3s var(--ease-out);
}
.btn:hover { background: transparent; color: var(--ink); }
.btn.ghost { background: transparent; color: var(--ink); }
.btn.ghost:hover { background: var(--ink); color: #fff; }

.toc { margin-top: clamp(56px, 8vw, 96px); max-width: 880px; }
.toc .part { margin-top: 40px; }
.toc .part h2 { font-size: 1.15rem; font-weight: 800; display: flex; gap: 14px; align-items: baseline; flex-wrap: wrap; border-bottom: 1px solid var(--rule-strong); padding-bottom: 8px; }
.toc .part h2 span { font-weight: 400; color: var(--ink-2); font-size: 15px; }
.toc ol { list-style: none; margin: 0; padding: 0; }
.toc li { display: grid; grid-template-columns: 2.4em 1fr auto; gap: 4px 12px; padding: 14px 0; border-bottom: 1px solid var(--rule); align-items: baseline; }
.toc .n { font-family: var(--math); font-size: 18px; color: var(--infra); font-weight: 700; }
.toc li a { font-weight: 700; }
.toc li .no-link { font-weight: 700; color: var(--ink-2); }
.toc li p { grid-column: 2 / 4; margin: 0; color: var(--ink-2); font-size: 15px; }

/* ---------- Reading page (chapter, post) ---------- */

.reader { display: grid; grid-template-columns: 1fr; gap: 32px; padding-top: clamp(28px, 5vw, 56px); }
@media (min-width: 1040px) { .reader { grid-template-columns: 240px minmax(0, 38em); gap: 72px; } }

.precis { font-size: 14px; line-height: 1.6; order: 2; }
.precis h2 { font-size: 14px; font-weight: 700; margin-bottom: 10px; }
.precis ol { list-style: none; margin: 0; padding: 0; border-left: 1px solid var(--rule-strong); }
.precis li a { display: block; padding: 8px 0 8px 14px; text-decoration: none; color: var(--ink-2); margin-left: -1px; border-left: 3px solid transparent; }
.precis li a:hover { color: var(--ink); border-left-color: var(--infra); }
.precis li a b { display: block; color: var(--ink); font-weight: 700; }
.article { order: 1; min-width: 0; }
@media (max-width: 1039px) { .precis { order: 0; border: 1px solid var(--rule); padding: 14px 16px; } }
@media (min-width: 1040px) { .precis { order: 0; } .precis-inner { position: sticky; top: 24px; } }

.article .crumbs { font-size: 14px; color: var(--ink-2); margin-bottom: 14px; }
.article .crumbs a { text-decoration: none; } .article .crumbs a:hover { text-decoration: underline; }
.article h1 { font-size: clamp(1.9rem, 4vw, 2.8rem); font-weight: 800; letter-spacing: -0.02em; }
.article .meta { font-size: 14px; color: var(--ink-2); margin: 12px 0 28px; }
.article h2 { font-size: 1.5rem; font-weight: 800; margin: 2.4em 0 0.7em; scroll-margin-top: 24px; }
.article h3 { font-size: 1.15rem; font-weight: 700; margin: 1.8em 0 0.6em; }
.article p, .article li { font-size: 17.5px; }
.article ul, .article ol { padding-left: 1.4em; margin: 0 0 1em; }
.article li { margin: 0.3em 0; }
.article code { font-family: var(--mono); font-size: 0.88em; background: var(--paper-2); padding: 0.1em 0.35em; }
.article pre { background: var(--ink); color: #e9ebf0; padding: 18px 20px; overflow-x: auto; font-size: 14px; line-height: 1.65; margin: 1.4em 0; }
.article pre code { background: none; padding: 0; color: inherit; font-size: inherit; }
.article .table-wrap { overflow-x: auto; margin: 1.4em 0; }
.article table { border-collapse: collapse; width: 100%; font-size: 15px; }
.article th, .article td { text-align: left; padding: 10px 14px 10px 0; border-bottom: 1px solid var(--rule); vertical-align: top; }
.article th { border-bottom: 1px solid var(--rule-strong); font-weight: 700; white-space: nowrap; }

/* Each section closes by folding its takeaway (mirrors the précis rail) */
.takeaway { margin: 1.6em 0 0; padding: 14px 0 0; border-top: 1px solid var(--rule-strong); font-size: 16px; }
.takeaway b { margin-right: 8px; }

.draft-banner { background: var(--api-tint); color: var(--api-ink); padding: 12px 16px; font-size: 14px; margin-bottom: 26px; }

.figure-cd { margin: 1.6em 0; padding: 20px; border: 1px solid var(--rule); background: #fff; }
.figure-cd svg { display: block; width: 100%; height: auto; }
.figure-cd figcaption { font-size: 14px; color: var(--ink-2); margin-top: 10px; }

.pager { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; margin-top: 56px; border-top: 1px solid var(--rule-strong); padding-top: 20px; font-size: 15px; }
.pager a { text-decoration: none; display: block; }
.pager a span { display: block; color: var(--ink-2); font-size: 13px; }
.pager a b { font-weight: 700; } .pager a:hover b { text-decoration: underline; }
.pager .next { text-align: right; }

/* ---------- Small pages ---------- */

.page-head { padding-top: clamp(36px, 6vw, 72px); }
.page-head h1 { font-size: clamp(2rem, 4.4vw, 3.3rem); font-weight: 800; letter-spacing: -0.02em; }
.page-head p { color: var(--ink-2); max-width: 38em; margin-top: 12px; }
.prose { max-width: 38em; margin-top: 40px; }
.prose h2 { font-size: 1.35rem; font-weight: 800; margin: 2em 0 0.6em; }

.lost { padding: clamp(56px, 10vw, 120px) 0; }
.lost .eq { font-family: var(--math); font-size: clamp(1.6rem, 4vw, 2.8rem); margin: 0; }
.lost h1 { font-size: clamp(1.8rem, 4vw, 2.6rem); font-weight: 800; margin: 18px 0 10px; }

.columns h2.later { margin-top: 48px; }
.section.tight { margin-top: 48px; }

/* Home: recent updates as the right column of the thesis */
.recent { align-self: start; }
.recent-head { display: flex; justify-content: space-between; align-items: baseline; gap: 12px; border-bottom: 1px solid var(--rule-strong); padding-bottom: 10px; }
.recent-head h2 { font-size: 18px; font-weight: 800; }
.recent-head a { font-size: 14px; }
.recent .updates li { grid-template-columns: 1fr auto; grid-template-areas: "kind status" "title title"; gap: 2px 12px; padding: 14px 0; }
.recent .updates .kind { grid-area: kind; font-size: 13px; }
.recent .updates .status { grid-area: status; font-size: 12px; }
.recent .updates a { grid-area: title; font-size: 16px; line-height: 1.5; }
@media (min-width: 1040px) {
  .thesis { grid-template-columns: minmax(0, 1fr) 340px; }
  .thesis h1 { max-width: none; }
  .recent { padding-top: 10px; }
}

/* Report blog: quotes and display formulas */
.article blockquote { margin: 1.6em 0; padding: 2px 0 2px 20px; border-left: 1px solid var(--ink); }
.article blockquote p { font-size: 1.15rem; font-weight: 700; line-height: 1.6; margin: 0; }
.article .formula { font-family: var(--math); font-size: 1.25rem; line-height: 2; text-align: center; margin: 1.4em 0; overflow-x: auto; }
.formula .up { font-style: normal; }
.formula sub { font-size: 0.65em; }
.frac { display: inline-flex; flex-direction: column; vertical-align: middle; text-align: center; line-height: 1.25; margin: 0 4px; }
.frac > span + span { border-top: 1px solid currentColor; }
.article a { overflow-wrap: anywhere; }