/* ==========================================================================
   sashuv.github.io
   Colours are tokens on :root; dark mode redefines them under
   [data-theme="dark"] (set by the toggle, or from the system setting).
   ========================================================================== */

:root {
  --paper: #ffffff;
  --ink: #1b1d20;
  --muted: #5d636b;
  --faint: #8a9098;
  --line: #e4e6e9;
  --soft: #f4f5f7;
  --link: #1f4e8c;
  --code-bg: #f6f7f9;
  --fig-bg: #ffffff;

  --tag-green-bg: #e5f3ea;  --tag-green: #1e6b3a;
  --tag-teal-bg: #e2f1f3;   --tag-teal: #1c5e66;
  --tag-blue-bg: #e7eefa;   --tag-blue: #23498a;
  --tag-purple-bg: #efe9f8; --tag-purple: #5b3a8c;
  --tag-orange-bg: #fbeee2; --tag-orange: #8a4513;
  --tag-rose-bg: #fbe8ec;   --tag-rose: #8e2742;
  --tag-amber-bg: #fbf2d9;  --tag-amber: #7a5a06;
  --tag-slate-bg: #eceef1;  --tag-slate: #3f4854;

  --body: "Inter", -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --mono: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  --measure: 1080px;
  color-scheme: light;
}

:root[data-theme="dark"] {
  --paper: #141619;
  --ink: #e3e5e8;
  --muted: #9ba1a9;
  --faint: #737982;
  --line: #2a2e34;
  --soft: #1c1f23;
  --link: #8fb4e8;
  --code-bg: #1b1e22;
  --fig-bg: #f4f5f7;

  --tag-green-bg: #17301f;  --tag-green: #8fd3a6;
  --tag-teal-bg: #12302f;   --tag-teal: #86c9cf;
  --tag-blue-bg: #1b2742;   --tag-blue: #a3c0f2;
  --tag-purple-bg: #2a2140; --tag-purple: #c7aef0;
  --tag-orange-bg: #39261a; --tag-orange: #f0b07c;
  --tag-rose-bg: #3a1c25;   --tag-rose: #f0a3b6;
  --tag-amber-bg: #342a10;  --tag-amber: #e8c46a;
  --tag-slate-bg: #262a30;  --tag-slate: #b8c0ca;
  color-scheme: dark;
}

/* Without JavaScript, still follow the system setting. */
@media (prefers-color-scheme: dark) {
  :root:not([data-theme]) {
    --paper: #141619; --ink: #e3e5e8; --muted: #9ba1a9; --faint: #737982;
    --line: #2a2e34; --soft: #1c1f23; --link: #8fb4e8; --code-bg: #1b1e22; --fig-bg: #f4f5f7;
    color-scheme: dark;
  }
}

/* ---------- base ---------- */
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--body);
  font-size: 16px;
  line-height: 1.65;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}
img { max-width: 100%; height: auto; }
a { color: var(--link); text-decoration: none; }
a:hover { text-decoration: underline; text-underline-offset: 2px; }
:focus-visible { outline: 2px solid var(--link); outline-offset: 2px; border-radius: 3px; }
h1, h2, h3 { text-wrap: balance; }
.ico { width: 15px; height: 15px; flex: none; fill: currentColor; }

.wrap {
  max-width: var(--measure);
  margin: 0 auto;
  padding-inline: 32px;
  padding-block: 0 40px;
}

/* ---------- header ---------- */
.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
  padding: 22px 0;
}
.brand { font-weight: 600; font-size: 17px; color: var(--ink); }
.brand:hover { text-decoration: none; }
.nav { display: flex; align-items: center; gap: 22px; font-size: 15px; }
.nav a { color: var(--muted); }
.nav a:hover { color: var(--ink); text-decoration: none; }
.nav a[aria-current="page"] { color: var(--ink); font-weight: 600; }
.nav .ext { display: inline-flex; align-items: center; gap: 3px; }
.ext-ico { width: 11px; height: 11px; fill: none; stroke: currentColor; stroke-width: 1.6; }
.mode {
  display: grid; place-items: center;
  width: 32px; height: 32px; padding: 0;
  background: none; color: var(--muted);
  border: 0; border-radius: 6px;
  cursor: pointer;
}
.mode:hover { color: var(--ink); }
.mode svg { width: 16px; height: 16px; fill: none; stroke: currentColor; stroke-width: 1.6; stroke-linecap: round; }
.mode .sun { display: none; }
[data-theme="dark"] .mode .sun { display: block; }
[data-theme="dark"] .mode .moon { display: none; }

/* ---------- home: intro ---------- */
.hero {
  display: grid;
  grid-template-columns: 1fr 180px;
  gap: 56px;
  align-items: start;
  padding-top: 28px;
}
.hero h1 { font-size: 36px; font-weight: 600; line-height: 1.15; margin: 0 0 4px; letter-spacing: -0.02em; }
.hero .role { color: var(--muted); margin: 0 0 18px; font-size: 15px; }
.hero p { margin: 0 0 12px; }
.photo { width: 180px; height: 180px; border-radius: 6px; object-fit: cover; }
.social { list-style: none; margin: 18px 0 0; padding: 0; display: flex; flex-wrap: wrap; gap: 6px 20px; font-size: 15px; }
.social a { display: inline-flex; align-items: center; gap: 6px; color: var(--ink); }
.social a:hover { color: var(--link); text-decoration: none; }
.social .ico { color: var(--muted); }
.social a:hover .ico { color: var(--link); }

/* ---------- section headings ---------- */
main h2 {
  font-size: 12.5px;
  font-weight: 600;
  letter-spacing: 0.09em;
  text-transform: uppercase;
  color: var(--muted);
  margin: 56px 0 20px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--line);
}
section[id] { scroll-margin-top: 16px; }

/* ---------- research ---------- */
.research { display: grid; gap: 36px; }
.r { display: grid; grid-template-columns: 220px 1fr; gap: 28px; align-items: start; }
.fig {
  display: block;
  aspect-ratio: 8 / 5;
  border: 1px solid var(--line);
  border-radius: 6px;
  overflow: hidden;
  background: var(--fig-bg);
}
.fig img { width: 100%; height: 100%; object-fit: contain; display: block; }
.status { font-size: 13px; color: var(--muted); margin: 0 0 2px; }
.status b { font-weight: 600; color: var(--ink); }
.r-title { font-size: 20px; font-weight: 600; line-height: 1.3; margin: 2px 0 0; text-wrap: pretty; }
.r-title a { color: var(--ink); }
.r-title a:hover { color: var(--link); }
.authors { color: var(--muted); font-size: 14.5px; margin: 2px 0 0; }
.authors strong { color: var(--ink); font-weight: 600; }
.summary { margin: 6px 0 0; font-size: 15px; }
.r-foot { display: flex; flex-wrap: wrap; align-items: center; gap: 8px 16px; margin-top: 10px; }
.links { display: flex; flex-wrap: wrap; gap: 4px 14px; margin: 0; font-size: 14.5px; }

.tags { display: flex; flex-wrap: wrap; gap: 6px; list-style: none; margin: 0; padding: 0; }
.tag { font-size: 12.5px; font-weight: 500; line-height: 1; padding: 5px 10px; border-radius: 999px; background: var(--tag-slate-bg); color: var(--tag-slate); }
.tag-green  { background: var(--tag-green-bg);  color: var(--tag-green); }
.tag-teal   { background: var(--tag-teal-bg);   color: var(--tag-teal); }
.tag-blue   { background: var(--tag-blue-bg);   color: var(--tag-blue); }
.tag-purple { background: var(--tag-purple-bg); color: var(--tag-purple); }
.tag-orange { background: var(--tag-orange-bg); color: var(--tag-orange); }
.tag-rose   { background: var(--tag-rose-bg);   color: var(--tag-rose); }
.tag-amber  { background: var(--tag-amber-bg);  color: var(--tag-amber); }
.tag-slate  { background: var(--tag-slate-bg);  color: var(--tag-slate); }

/* ---------- experience / education ---------- */
.xp { list-style: none; margin: 0; padding: 0; display: grid; gap: 18px; }
.xp li { display: grid; grid-template-columns: 22px 1fr; gap: 12px; align-items: start; }
.logo { width: 22px; height: 22px; margin-top: 3px; border-radius: 4px; border: 1px solid var(--line); background: #fff; object-fit: contain; padding: 1px; display: block; }
.xp-line { display: flex; justify-content: space-between; align-items: baseline; flex-wrap: wrap; gap: 0 16px; }
.xp-role { font-size: 16.5px; font-weight: 600; margin: 0; line-height: 1.35; }
.when { color: var(--muted); font-size: 14px; white-space: nowrap; font-variant-numeric: tabular-nums; }
.xp-org { color: var(--muted); font-size: 14.5px; margin: 0; }
.xp-org a { color: inherit; }
.xp-org a:hover { color: var(--link); }

/* ---------- news ---------- */

.news { list-style: none; margin: 0; padding: 0; display: grid; gap: 8px; font-size: 15px; }
.news li { display: grid; grid-template-columns: 80px 1fr; gap: 16px; }
.news .when { padding-top: 1px; }

/* ---------- footer ---------- */
.site-footer {
  margin-top: 64px;
  padding-top: 16px;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 13.5px;
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 6px;
}

/* ---------- blog index ---------- */
.page-head { padding-top: 28px; }
.page-head h1 { font-size: 30px; font-weight: 600; margin: 0 0 4px; }
.page-head p { margin: 0; color: var(--muted); }
.rss { display: inline-flex; align-items: center; gap: 4px; margin-left: 6px; font-size: 15px; }
.rss .ico { width: 12px; height: 12px; }
.posts { margin-top: 28px; }
.post-card {
  display: grid;
  grid-template-columns: 240px 1fr;
  gap: 22px;
  padding: 24px 0;
  border-top: 1px solid var(--line);
  color: inherit;
}
.post-card:hover { text-decoration: none; }
.post-card:hover .post-title { color: var(--link); }
.thumb {
  aspect-ratio: 8 / 5;
  border: 1px solid var(--line);
  border-radius: 6px;
  overflow: hidden;
  background: var(--fig-bg);
}
.thumb img { width: 100%; height: 100%; object-fit: cover; display: block; }
.thumb img.default { object-position: center 30%; }
.post-card time { font-size: 13.5px; color: var(--muted); }
.post-title { font-size: 19px; font-weight: 600; line-height: 1.35; margin: 2px 0 6px; color: var(--ink); text-transform: none; letter-spacing: 0; border: 0; padding: 0; }
.post-desc { margin: 0 0 10px; color: var(--muted); font-size: 15px; }

/* ---------- articles (posts and research pages) ---------- */
.article-head { max-width: 780px; padding-top: 28px; margin-bottom: 28px; display: grid; gap: 8px; }
.article-head h1 { font-size: 32px; font-weight: 600; line-height: 1.2; margin: 0; letter-spacing: -0.01em; }
.kicker { margin: 0; font-size: 14px; letter-spacing: 0.08em; text-transform: uppercase; }
.kicker a { color: var(--muted); }
.meta { margin: 0; color: var(--muted); font-size: 15px; }
.meta strong { color: var(--ink); }
.article-head .status { margin: 0; font-size: 15px; }
.lead-figure { margin: 0 0 32px; max-width: 780px; }
.lead-figure img { display: block; width: 100%; border: 1px solid var(--line); border-radius: 6px; background: var(--fig-bg); }
.lead-figure figcaption { margin-top: 8px; color: var(--muted); font-size: 15px; }
.back { margin-top: 48px; }

/* Long-form text: blog posts and research pages */
.prose { font-size: 16.5px; line-height: 1.75; overflow-wrap: break-word; max-width: 780px; }
.prose > * + * { margin-top: 1.1em; }
.prose p, .prose ul, .prose ol, .prose pre, .prose table, .prose blockquote, .prose figure { margin-bottom: 0; }
.prose h1, .prose h2, .prose h3, .prose h4 {
  color: var(--ink);
  text-transform: none;
  letter-spacing: -0.005em;
  border: 0;
  padding: 0;
  line-height: 1.3;
  margin: 2em 0 0;
  font-weight: 600;
}
.prose h1, .prose h2 { font-size: 22px; }
.prose h3 { font-size: 18.5px; }
.prose h4 { font-size: 16.5px; }
.prose ul, .prose ol { padding-left: 1.3em; }
.prose li + li { margin-top: 0.35em; }
.prose img { display: block; margin-inline: auto; border-radius: 4px; }
.prose hr { border: 0; border-top: 1px solid var(--line); margin: 2.4em 0; }
.prose blockquote { margin-inline: 0; padding: 2px 0 2px 18px; border-left: 3px solid var(--line); color: var(--muted); }
.prose table { display: block; width: max-content; max-width: 100%; overflow-x: auto; border-collapse: collapse; font-size: 16px; }
.prose th, .prose td { border: 1px solid var(--line); padding: 6px 12px; text-align: left; }
.prose th { background: var(--soft); font-weight: 600; }
.prose .katex-display { overflow-x: auto; overflow-y: hidden; padding: 4px 0; }
.prose :not(pre) > code {
  font-family: var(--mono);
  font-size: 0.86em;
  background: var(--code-bg);
  border: 1px solid var(--line);
  border-radius: 4px;
  padding: 0.1em 0.35em;
}
.prose pre, .prose .highlight {
  font-family: var(--mono);
  font-size: 13.5px;
  line-height: 1.6;
  background: var(--code-bg);
  border: 1px solid var(--line);
  border-radius: 6px;
}
.prose pre { padding: 14px 16px; overflow-x: auto; }
.prose .highlight pre { border: 0; margin: 0; background: none; }
.prose div.highlighter-rouge { margin-top: 1.1em; }

/* Syntax highlighting (Rouge) */
.highlight .c, .highlight .c1, .highlight .cm, .highlight .cs { color: #6a737d; font-style: italic; }
.highlight .k, .highlight .kd, .highlight .kn, .highlight .kc, .highlight .kr, .highlight .ow { color: #a3165a; }
.highlight .s, .highlight .s1, .highlight .s2, .highlight .sd, .highlight .si, .highlight .sa { color: #1a7f37; }
.highlight .m, .highlight .mi, .highlight .mf, .highlight .mh { color: #9a4d00; }
.highlight .nf, .highlight .fm { color: #3a5bb8; }
.highlight .nc, .highlight .nn { color: #7a3fb0; }
.highlight .nb, .highlight .bp { color: #0f6f7a; }
.highlight .o { color: var(--muted); }
[data-theme="dark"] .highlight .c, [data-theme="dark"] .highlight .c1, [data-theme="dark"] .highlight .cm, [data-theme="dark"] .highlight .cs { color: #7d8590; }
[data-theme="dark"] .highlight .k, [data-theme="dark"] .highlight .kd, [data-theme="dark"] .highlight .kn, [data-theme="dark"] .highlight .kc, [data-theme="dark"] .highlight .kr, [data-theme="dark"] .highlight .ow { color: #f08fb7; }
[data-theme="dark"] .highlight .s, [data-theme="dark"] .highlight .s1, [data-theme="dark"] .highlight .s2, [data-theme="dark"] .highlight .sd, [data-theme="dark"] .highlight .si, [data-theme="dark"] .highlight .sa { color: #8fd3a6; }
[data-theme="dark"] .highlight .m, [data-theme="dark"] .highlight .mi, [data-theme="dark"] .highlight .mf, [data-theme="dark"] .highlight .mh { color: #f0b07c; }
[data-theme="dark"] .highlight .nf, [data-theme="dark"] .highlight .fm { color: #a3c0f2; }
[data-theme="dark"] .highlight .nc, [data-theme="dark"] .highlight .nn { color: #c7aef0; }
[data-theme="dark"] .highlight .nb, [data-theme="dark"] .highlight .bp { color: #86c9cf; }

/* ---------- small screens ---------- */
@media (max-width: 640px) {
  body { font-size: 14.5px; }
  .site-header { padding: 16px 0; }
  .brand { font-size: 16.5px; }
  .nav { font-size: 14px; }
  .hero .role { font-size: 14.5px; margin-bottom: 14px; }
  .social { font-size: 14px; }
  main h2 { font-size: 12.5px; margin: 44px 0 16px; }
  .status { font-size: 13px; }
  .authors { font-size: 14px; }
  .summary { font-size: 14px; }
  .tag { font-size: 12.5px; padding: 4px 9px; }
  .links { font-size: 14.5px; }
  .xp-role { font-size: 15px; }
  .xp-org, .when { font-size: 13px; }
  .news { font-size: 14px; }
  .page-head h1 { font-size: 26px; }
  .post-title { font-size: 17px; }
  .post-desc { font-size: 14px; }
  .post-card time { font-size: 13.5px; }
  .meta { font-size: 14.5px; }
  .lead-figure figcaption { font-size: 13.5px; }
  .site-footer { font-size: 13px; }
  .wrap { padding-inline: 18px; }
  .nav { gap: 16px; }
  .hero { grid-template-columns: 1fr; gap: 18px; padding-top: 8px; }
  .photo { order: -1; width: 112px; height: 112px; }
  .hero h1 { font-size: 26px; }
  .r, .post-card { grid-template-columns: 1fr; gap: 12px; }
  .r-title { font-size: 17px; }
  .news li { grid-template-columns: 1fr; gap: 0; }
  .article-head h1 { font-size: 25px; }
  .prose { font-size: 15.5px; }
  .prose h1, .prose h2 { font-size: 20px; }
  .prose h3 { font-size: 18px; }
  .prose pre, .prose .highlight { font-size: 13px; }
}

@media (prefers-reduced-motion: no-preference) {
  html { scroll-behavior: smooth; }
}