/* ============================================================
   Xiefan Guo — personal site
   Shared stylesheet for: index / papers / activities / blog.

   Layout & type scale:
     · Two-column hero — left photo + side links, right intro
     · Content column offset to align under the intro
     · Body & headings → EB Garamond (hierarchy by size, not typeface)
     · Cormorant Garamond → date / label small-caps accents only
     · Link color → #191970 (midnight blue)
   Fonts are self-hosted (assets/fonts/) so the page never depends
   on any external font service being reachable.
   ============================================================ */

/* ---------- Self-hosted fonts ---------- */
@font-face {
  font-family: "Cormorant Garamond";
  font-style: normal; font-weight: 500 600; font-display: block;
  src: url("../fonts/cormorant-garamond-latin-500-600.woff2") format("woff2");
}
@font-face {
  font-family: "EB Garamond";
  font-weight: 400; font-style: normal; font-display: block;
  src: url("../fonts/EBGaramond12-Regular.woff") format("woff");
}
@font-face {
  font-family: "EB Garamond";
  font-weight: 400; font-style: italic; font-display: block;
  src: url("../fonts/EBGaramond12-Italic.woff") format("woff");
}
/* Medium (500) is what `b, strong` asks for. Before it was registered, that
   request had no 500 face to match and CSS font matching resolved it down to
   Regular — bold text rendered identical to body copy. Real face, not a
   synthesised one, so the cupped foot serifs stay intact. */
@font-face {
  font-family: "EB Garamond";
  font-weight: 500; font-style: normal; font-display: block;
  src: url("../fonts/EBGaramond12-Medium.woff") format("woff");
}
@font-face {
  font-family: "EB Garamond";
  font-weight: 500; font-style: italic; font-display: block;
  src: url("../fonts/EBGaramond12-MediumItalic.woff") format("woff");
}
@font-face {
  font-family: "EB Garamond";
  font-weight: 600; font-style: normal; font-display: block;
  src: url("../fonts/EBGaramond12-Semibold.woff") format("woff");
}
@font-face {
  font-family: "EB Garamond";
  font-weight: 600; font-style: italic; font-display: block;
  src: url("../fonts/EBGaramond12-SemiboldItalic.woff") format("woff");
}
/* 700/800 complete the specimen's 400–800 range. Nothing requests them today,
   so the browser never downloads them — an unmatched @font-face costs no
   bytes. They exist so any future `font-weight: bold` resolves to a drawn
   face instead of a synthetic smear. */
@font-face {
  font-family: "EB Garamond";
  font-weight: 700; font-style: normal; font-display: block;
  src: url("../fonts/EBGaramond12-Bold.woff") format("woff");
}
@font-face {
  font-family: "EB Garamond";
  font-weight: 700; font-style: italic; font-display: block;
  src: url("../fonts/EBGaramond12-BoldItalic.woff") format("woff");
}
@font-face {
  font-family: "EB Garamond";
  font-weight: 800; font-style: normal; font-display: block;
  src: url("../fonts/EBGaramond12-ExtraBold.woff") format("woff");
}
@font-face {
  font-family: "EB Garamond";
  font-weight: 800; font-style: italic; font-display: block;
  src: url("../fonts/EBGaramond12-ExtraBoldItalic.woff") format("woff");
}

/* ---------- Design tokens ---------- */
:root {
  --bg: #ffffff;
  --text: #1a1a1a;
  --muted: #2f2b28;
  --link: #191970;
  --accent: #191970;
  --link-hover: #333399;

  --body-font: "EB Garamond", Georgia, Garamond, serif;
  --label-font: "Cormorant Garamond", "Palatino Linotype", "Book Antiqua", serif;

  --page-width: 1380px;
  --hero-image: 258px;
  --hero-gap: 70px;
  --content-width: 800px;

  /* Type scale — tuned for EB Garamond, larger & tighter (specimen feel).
     Names are historical; the comment on each line is the authoritative
     list of what actually consumes it. */
  --fs-h1: 33px;        /* .wordmark                                   */
  --fs-h2: 29px;        /* .section-title                              */
  --fs-lead: 19px;      /* body default, .callout                      */
  --fs-intro: 19.5px;   /* .intro p, .opp-list li, .opt-callout        */
  --fs-paper: 19.5px;   /* .paper entries (title, authors, venue, link)*/
  --fs-body-lg: 19px;   /* .article-body — blog post body              */
  --fs-body: 17px;      /* .side-links, .linkrow, .tbody, .paper .venue,
                           .post-list-summary                          */
  --fs-meta: 15.5px;    /* .nav, .tdate, .article-meta, .article-foot,
                           .section-title .note, .more                 */
  --fs-micro: 13.5px;   /* .callout-label, .opt-callout .tag           */
}

* { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
  /* Always reserve room for the vertical scrollbar so toggling long content
     (e.g. "Show earlier news") never shifts the centered layout sideways.
     overflow-y:scroll is the broadly-supported fallback for scrollbar-gutter. */
  overflow-y: scroll;
  scrollbar-gutter: stable;
}

html, body { margin: 0; padding: 0; background: var(--bg); color: var(--text); }

body {
  font-family: var(--body-font);
  font-size: var(--fs-lead);
  line-height: 1.4;
  font-weight: 400;
  /* Rendering matched to googlefonts.github.io/ebgaramond-specimen, which
     serves the byte-identical EBGaramond12 woffs. It sets only grayscale
     smoothing — no text-shadow, no text-rendering, no feature overrides.
     EB Garamond 12's foot serifs are cupped by design (the `n` foot runs
     y=-3 at the tips to y=+2 at the stem, ~5/1000 em). At 19px that arch is
     sub-pixel, so it only ever surfaces as antialiasing at the baseline —
     a blur-radius text-shadow spread it into a visible bowed edge, and
     optimizeLegibility nudged the same pixels. Dropping both restores the
     flat-looking baseline the specimen shows. */
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

a {
  color: var(--link);
  text-decoration: none;
  text-decoration-thickness: 1px;
  text-underline-offset: 2px;
  text-decoration-color: rgba(25, 25, 112, 0.5);
}
a:hover { opacity: 0.82; }

b, strong { font-weight: 500; }

/* ---------- Page frame ---------- */
.wrap {
  max-width: var(--page-width);
  margin: 0 auto;
  padding: 42px 56px 96px;
}

/* ---------- Top bar: wordmark + nav ---------- */
.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 32px;
}
.wordmark {
  color: var(--text);
  text-decoration: none;
  font-size: var(--fs-h1);
  line-height: 1;
  font-weight: 400;
  letter-spacing: -0.01em;
}
.wordmark:hover { opacity: 1; }
.nav {
  display: flex;
  align-items: center;
  gap: 22px;
  flex-wrap: wrap;
  font-size: 16px;
  line-height: 1.35;
}
.nav a { color: var(--text); text-decoration: none; opacity: 0.88; }
.nav a.active {
  opacity: 1;
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 6px;
  text-decoration-color: rgba(31, 27, 24, 0.7);
}

/* ---------- Hero: two-column (photo/side-links + intro) ---------- */
.hero {
  display: grid;
  grid-template-columns: var(--hero-image) minmax(0, 680px);
  gap: var(--hero-gap);
  align-items: start;
  margin-top: 92px;
  margin-left: 64px;
  margin-bottom: 0;
}
.hero-side { width: var(--hero-image); }
.portrait {
  width: var(--hero-image);
  aspect-ratio: 1 / 1;
  object-fit: cover;
  object-position: center 28%;
  display: block;
  background: #d8d4ce;
}
.side-links {
  margin: 14px 0 0;
  font-size: var(--fs-body);
  line-height: 1.5;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 3px;
}
.side-links a {
  color: var(--link);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 2px;
  text-decoration-color: rgba(25, 25, 112, 0.5);
  white-space: nowrap;
}
.side-plain { color: var(--text); white-space: nowrap; }

.intro { max-width: 680px; padding-top: 6px; }
.intro p { margin: 0 0 16px; font-size: var(--fs-intro); font-weight: 400; }
.intro p:last-child { margin-bottom: 0; }
.intro .linkrow { margin-top: 26px; font-size: var(--fs-body); }

/* Open-to-opportunities callout */
.callout {
  margin-top: 22px;
  padding: 12px 16px 12px 17px;
  border-left: 2px solid rgba(25, 25, 112, 0.34);
  box-shadow: inset 0 0 0 1px rgba(25, 25, 112, 0.05);
  font-size: var(--fs-lead);
  font-weight: 400;
  line-height: 1.5;
}
.callout-label {
  font-variant: small-caps;
  letter-spacing: 0.045em;
  font-size: var(--fs-micro);
  color: red;
  font-weight: 600;
  margin-right: 4px;
}

/* Open-to-opportunities list */
.opp-list {
  margin: 0;
  padding-left: 1.15em;
}
.opp-list li {
  font-size: var(--fs-intro);
  font-weight: 400;
  line-height: 1.5;
  margin-bottom: 10px;
}
.opp-list li:last-child { margin-bottom: 0; }
.opp-list li::marker { color: var(--muted); }

/* ===== TEMP: four Open-to-Opportunities style options (for comparison) ===== */
.opt-callout {
  margin-top: 24px;
  padding: 7px 14px 7px 15px;
  background: rgba(255, 255, 255, 0.32);
  border-left: 2px solid rgba(25, 25, 112, 0.34);
  box-shadow: inset 0 0 0 1px rgba(25, 25, 112, 0.05);
  font-size: var(--fs-intro);
  font-weight: 400;
  line-height: 1.4;
}
.opt-callout .lbl {
  font-variant: small-caps; letter-spacing: 0.045em;
  font-size: var(--fs-micro); color: red; font-weight: 600; margin-right: 4px;
}
.opt-banner {
  margin: 22px 0 0;
  padding: 16px 20px;
  background: rgba(25, 25, 112, 0.06);
  border: 1px solid rgba(25, 25, 112, 0.18);
  border-radius: 6px;
}
.opt-banner .head {
  display: block;
  font-family: var(--label-font);
  font-variant: small-caps; letter-spacing: 0.05em;
  font-size: 16px; font-weight: 600; color: red;
  margin-bottom: 5px;
}
.opt-banner .body { font-size: var(--fs-intro); font-weight: 400; line-height: 1.5; }
/* ===== END TEMP ===== */

/* ---------- Content column: offset to align under intro ---------- */
.content {
  max-width: var(--content-width);
  margin-left: calc(64px + var(--hero-image) + var(--hero-gap));
  margin-top: 20px;
}

/* Standalone pages (Papers / Activities / Blog) are single-column with no
   hero, so they keep the home page's right-shifted feel but with a smaller
   offset than home (which must clear the 258px portrait column). */
.content.page {
  margin-left: 264px;
}

/* ---------- Section heading ---------- */
.section {
  margin-top: 48px;
  scroll-margin-top: 28px;
}
.section:first-child { margin-top: 0; }
.section-title {
  margin: 0 0 16px;
  font-size: var(--fs-h2);
  line-height: 1.14;
  font-weight: 400;
  letter-spacing: -0.01em;
  color: var(--text);
}
.section-title .note {
  font-size: var(--fs-meta);
  font-weight: 400;
  letter-spacing: 0;
  color: var(--muted);
  margin-left: 8px;
}
/* Larger page-level heading (Papers page), set apart from the list */
.section-title.page-title {
  font-size: 36px;
  margin-bottom: 44px;
}

/* ---------- Timeline (date gutter + content) ---------- */
.timeline { display: grid; row-gap: 5px; }
.trow {
  display: grid;
  grid-template-columns: 58px minmax(0, 1fr);
  column-gap: 12px;
  align-items: baseline;
}
.tdate {
  font-family: var(--label-font);
  font-size: var(--fs-meta);
  line-height: 1.4;
  color: var(--muted);
  white-space: nowrap;
  font-weight: 600;
  letter-spacing: 0.015em;
}
.tbody { min-width: 0; font-size: var(--fs-body); font-weight: 400; line-height: 1.4; }
.tbody .sub { color: var(--muted); font-size: var(--fs-meta); }

/* ---------- Papers page ---------- */
.paper {
  display: grid;
  grid-template-columns: 104px minmax(0, 1fr);
  column-gap: 18px;
  align-items: start;
  margin-bottom: 16px;
}
.paper .venue {
  padding-top: 4px;
  font-family: var(--label-font);
  font-size: var(--fs-body);
  line-height: 1.3;
  color: var(--muted);
  white-space: nowrap;
  font-weight: 600;
  letter-spacing: 0.015em;
  text-align: right;
  justify-self: end;
}
.paper-main { min-width: 0; display: grid; row-gap: 0; }
.paper .ptitle {
  font-size: var(--fs-paper);
  line-height: 1.3;
  color: var(--link);
  font-weight: 400;
}
.paper .ptitle a { color: var(--link); text-decoration: none; }
.paper .ptitle a:hover { color: var(--link-hover); opacity: 1; }
.paper .authors { font-size: var(--fs-paper); line-height: 1.3; color: var(--text); font-weight: 400; }
.paper .authors .me { font-weight: 600; }
.paper .venue-full { font-size: var(--fs-paper); line-height: 1.3; color: var(--text); font-weight: 400; }
.paper .venue-full em { font-style: italic; }
.paper .plink { font-size: var(--fs-paper); line-height: 1.3; }
.paper .plink a { color: var(--link); text-decoration: none; }
.paper .plink a:hover { text-decoration: underline; text-underline-offset: 2px; opacity: 1; }

/* Small-caps method names in titles */
.sc { font-variant: small-caps; }

/* When a paper has no venue label, keep the main column aligned */
.paper.no-venue { grid-template-columns: 78px minmax(0, 1fr); }

/* ---------- Blog: table of contents (blog.html) ---------- */
.post-list { list-style: none; margin: 0; padding: 0; }
.post-list-item {
  display: grid;
  grid-template-columns: 78px minmax(0, 1fr);
  column-gap: 22px;
  align-items: baseline;
  margin-bottom: 30px;
}
.post-list-date {
  font-family: var(--label-font);
  font-size: 15.5px;
  font-weight: 600;
  letter-spacing: 0.015em;
  color: var(--muted);
  white-space: nowrap;
}
.post-list-main { min-width: 0; }
.post-list-title {
  display: inline-block;
  font-size: 21px;
  line-height: 1.3;
  color: var(--link);
  text-decoration: none;
}
.post-list-title:hover { color: var(--link-hover); opacity: 1; }
.post-list-summary {
  margin: 6px 0 0;
  font-size: var(--fs-body);
  font-weight: 400;
  line-height: 1.5;
  color: var(--muted);
}

/* ---------- Blog: single article (posts/*.html) ---------- */
.article-head { margin-bottom: 30px; }
.article-title {
  font-size: 34px;
  line-height: 1.15;
  font-weight: 400;
  letter-spacing: -0.01em;
  margin: 0 0 8px;
  color: var(--text);
}
.article-meta {
  font-family: var(--label-font);
  font-size: var(--fs-meta);
  font-weight: 600;
  letter-spacing: 0.015em;
  color: var(--muted);
}
.article-body { font-size: var(--fs-body-lg); font-weight: 400; line-height: 1.35; }
.article-body p { margin: 0 0 18px; }

/* MathJax — keep formulas in scale with the body text. mjx-container renders
   relative to the surrounding font-size, so these are body-relative; the
   global MathJax `scale` in each post's config trims the rest. */
.article-body mjx-container { font-size: 1.06em; }
.article-body mjx-container[display="true"] {
  font-size: 1.12em;
  margin: 16px 0;
  overflow-x: auto;
  overflow-y: hidden;
}
.article-body h2 {
  font-size: 22px;
  line-height: 1.2;
  font-weight: 600;
  letter-spacing: -0.005em;
  margin: 34px 0 12px;
  color: var(--text);
}
.article-body blockquote {
  margin: 22px 0;
  padding: 4px 0 4px 18px;
  border-left: 2px solid rgba(25, 25, 112, 0.34);
  font-style: italic;
  color: var(--muted);
}
.article-body ul,
.article-body ol { margin: 0 0 18px; padding-left: 1.3em; }
.article-body li { margin-bottom: 6px; }
.article-body code {
  font-family: "SFMono-Regular", Menlo, Consolas, monospace;
  font-size: 0.85em;
  background: rgba(25, 25, 112, 0.06);
  padding: 1px 5px;
  border-radius: 3px;
}
.article-foot {
  margin-top: 40px;
  padding-top: 18px;
  border-top: 1px solid var(--rule);
  font-size: var(--fs-meta);
}

/* ---------- Professional activities ---------- */
.activity-group p { margin: 0 0 12px; font-size: 17px; font-weight: 400; }
.activity-label {
  display: block;
  margin-bottom: 4px;
  font-size: 15px;
  line-height: 1.45;
  font-variant: small-caps;
  letter-spacing: 0.05em;
  color: var(--muted);
}

/* ---------- News "show earlier" toggle ---------- */
.more {
  margin-top: 12px;
  padding: 0;
  background: none;
  border: 0;
  color: var(--accent);
  font: inherit;
  font-size: var(--fs-meta);
  cursor: pointer;
  text-decoration: underline;
  text-underline-offset: 2px;
}
.hidden { display: none; }

/* ---------- Empty-page placeholder (Blog / Thoughts) ---------- */
.placeholder { color: var(--muted); font-size: 17px; font-style: italic; }

/* ---------- Responsive ---------- */
@media (max-width: 1080px) {
  .wrap { padding: 40px 34px 84px; }
  .hero {
    margin-left: 0;
    grid-template-columns: 222px minmax(0, 1fr);
    gap: 42px;
  }
  .portrait, .hero-side { width: 222px; }
  .content { margin-left: calc(222px + 42px); max-width: none; }
  .content.page { margin-left: 0; }
}

@media (max-width: 780px) {
  :root {
    --fs-h2: 25px;
    --fs-lead: 15.5px;
    --fs-intro: 16.5px;
    --fs-body: 14.8px;
    --fs-meta: 13.75px;
    /* Note: --fs-body-lg and --fs-paper are intentionally not scaled down
       here, so blog body text and paper entries keep their desktop size. */
  }
  body { line-height: 1.5; }
  .wrap { padding: 30px 20px 60px; }
  .topbar { flex-direction: column; align-items: flex-start; gap: 16px; }
  .nav { gap: 16px; }
  .hero {
    margin-top: 48px;
    grid-template-columns: 1fr;
    gap: 24px;
  }
  .portrait, .hero-side { width: min(244px, 100%); }
  .intro { max-width: none; padding-top: 0; }
  .content { margin-left: 0; margin-top: 50px; }
  .section { margin-top: 50px; }
  .trow { grid-template-columns: 58px minmax(0, 1fr); column-gap: 10px; }
  .paper { grid-template-columns: 90px minmax(0, 1fr); column-gap: 10px; }
}