/* ---- csemx site ---------------------------------------------------------- */
:root {
  --bg:        #ffffff;
  --bg-alt:    #f5f8fa;
  --ink:       #15232b;
  --ink-soft:  #41535d;
  --muted:     #66767f;
  --line:      #e2e9ee;
  --accent:    #0c7f91;
  --accent-ink:#075f6d;
  --code-bg:   #0f2730;
  --code-ink:  #d7e7ec;
  --code-cmt:  #6f9aa6;
  --radius:    10px;
  --maxw:      980px;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg:       #0c1418;
    --bg-alt:   #101c22;
    --ink:      #e7eef2;
    --ink-soft: #b4c2ca;
    --muted:    #8497a0;
    --line:     #21323b;
    --accent:   #36c2d6;
    --accent-ink:#7fe0ee;
    --code-bg:  #0a151a;
    --code-ink: #d4e6ec;
  }
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 80px; }
body {
  margin: 0;
  font-family: "Inter", system-ui, -apple-system, Segoe UI, Roboto, sans-serif;
  color: var(--ink);
  background: var(--bg);
  line-height: 1.62;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
.wrap { max-width: var(--maxw); margin: 0 auto; padding: 0 24px; }
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
code, pre, .filetree { font-family: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, monospace; }

/* ---- header -------------------------------------------------------------- */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: color-mix(in srgb, var(--bg) 90%, transparent);
  backdrop-filter: saturate(140%) blur(10px);
  border-bottom: 1px solid var(--line);
}
.nav-wrap { display: flex; align-items: center; justify-content: space-between; height: 56px; }
.brand { display: inline-flex; align-items: center; gap: 9px; font-weight: 700; font-size: 1.1rem;
  color: var(--ink); letter-spacing: -.01em; }
.brand:hover { text-decoration: none; }
.brand-mark { color: var(--accent); }
.site-nav { display: flex; align-items: center; gap: 22px; }
.site-nav a { color: var(--ink-soft); font-weight: 500; font-size: .93rem; }
.site-nav a:hover { color: var(--accent); text-decoration: none; }
.nav-gh { color: var(--ink) !important; font-weight: 600 !important; }
@media (max-width: 620px) {
  .site-nav { gap: 14px; }
  .site-nav a:not(.nav-gh) { display: none; }
}

/* ---- intro --------------------------------------------------------------- */
.intro { padding: 56px 0 36px; border-bottom: 1px solid var(--line); }
.intro-title { font-size: clamp(2.4rem, 6vw, 3.2rem); line-height: 1; margin: 0 0 14px;
  letter-spacing: -.03em; font-weight: 700; }
.intro-sub { font-size: clamp(1.1rem, 2.4vw, 1.3rem); font-weight: 500; max-width: 56ch;
  margin: 0 0 12px; color: var(--ink); }
.intro-status { color: var(--muted); font-size: .95rem; margin: 0 0 24px; }
.intro-links { display: flex; flex-wrap: wrap; gap: 22px; }
.intro-links a { font-weight: 600; font-size: .98rem; }

/* ---- sections ------------------------------------------------------------ */
.section { padding: 36px 0; }
.section + .section { border-top: 1px solid var(--line); }
.col-h { font-size: 1.2rem; letter-spacing: -.01em; margin: 0 0 14px; }
.muted { color: var(--ink-soft); }
.prose { max-width: 70ch; }
.prose p { color: var(--ink-soft); }
.prose p + p { margin-top: 1em; }

.two-col { display: grid; grid-template-columns: 1fr 1fr; gap: 36px; }
.two-col.wide-left { grid-template-columns: 1fr 1fr; align-items: start; }
@media (max-width: 720px) { .two-col, .two-col.wide-left { grid-template-columns: 1fr; gap: 24px; } }

.plain { list-style: none; margin: 0; padding: 0; }
.plain li { position: relative; padding: 6px 0 6px 18px; color: var(--ink-soft);
  border-top: 1px solid var(--line); }
.plain li:first-child { border-top: 0; }
.plain li::before { content: "–"; position: absolute; left: 0; color: var(--accent); }

/* code + file tree */
.code, .filetree { background: var(--code-bg); color: var(--code-ink); border-radius: var(--radius);
  padding: 18px 20px; overflow-x: auto; font-size: .88rem; line-height: 1.65; margin: 0; }
.code .cmt, .filetree .cmt { color: var(--code-cmt); }

/* inline code on light sections */
.prose code, .muted code, .col-h code, .two-col code {
  background: color-mix(in srgb, var(--accent) 10%, var(--bg-alt));
  color: var(--accent-ink); padding: .12em .38em; border-radius: 5px; font-size: .88em; }

/* ---- footer -------------------------------------------------------------- */
.site-footer { border-top: 1px solid var(--line); background: var(--bg-alt); padding: 32px 0; margin-top: 8px; }
.foot-lead { color: var(--ink-soft); max-width: 60ch; margin: 0 0 14px; font-size: .95rem; }
.foot-links { display: flex; flex-wrap: wrap; gap: 20px; margin-bottom: 12px; }
.foot-links a { color: var(--ink); font-weight: 500; font-size: .92rem; }
.foot-meta { color: var(--muted); font-size: .85rem; margin: 0; }

/* ---- doc pages (spec / rationale) --------------------------------------- */
.doc-wrap { display: grid; grid-template-columns: 240px 1fr; gap: 48px; padding-top: 40px; padding-bottom: 72px; }
.doc-wrap.no-toc { grid-template-columns: 1fr; }
.doc-wrap.no-toc .toc { display: none; }
@media (max-width: 900px) { .doc-wrap { grid-template-columns: 1fr; } .toc { display: none !important; } }

.toc { position: sticky; top: 80px; align-self: start; max-height: calc(100vh - 104px); overflow-y: auto;
  font-size: .85rem; border-left: 2px solid var(--line); padding-left: 2px; }
.toc-title { text-transform: uppercase; letter-spacing: .08em; font-size: .7rem; font-weight: 700;
  color: var(--muted); margin: 0 0 10px 16px; }
#toc-nav { display: flex; flex-direction: column; }
#toc-nav a { color: var(--ink-soft); padding: 5px 0 5px 16px; margin-left: -2px;
  border-left: 2px solid transparent; line-height: 1.35; }
#toc-nav a:hover { color: var(--accent); text-decoration: none; }
#toc-nav a.active { color: var(--accent); border-left-color: var(--accent); font-weight: 600; }
#toc-nav a.toc-h3 { padding-left: 30px; font-size: .82rem; }

.doc-content { min-width: 0; max-width: 760px; grid-column: 2; }
.doc-wrap.no-toc .doc-content { grid-column: 1; max-width: 820px; }
@media (max-width: 900px) { .doc-content { grid-column: 1; } }
.doc-content h1 { font-size: clamp(1.9rem, 5vw, 2.4rem); letter-spacing: -.03em; margin: 0 0 .5em; line-height: 1.12; }
.doc-content h2 { font-size: 1.55rem; letter-spacing: -.02em; margin: 2.1em 0 .6em;
  padding-bottom: .3em; border-bottom: 1px solid var(--line); }
.doc-content h3 { font-size: 1.2rem; margin: 1.7em 0 .5em; }
.doc-content h4 { font-size: 1.04rem; margin: 1.4em 0 .4em; }
.doc-content p, .doc-content li { color: var(--ink-soft); }
.doc-content strong { color: var(--ink); }
.doc-content a { font-weight: 500; }
.doc-content blockquote { margin: 1.4em 0; padding: 10px 18px; border-left: 3px solid var(--accent);
  background: var(--bg-alt); border-radius: 0 8px 8px 0; color: var(--ink-soft); }
.doc-content blockquote p { margin: .3em 0; }
.doc-content code { background: color-mix(in srgb, var(--accent) 10%, var(--bg-alt));
  color: var(--accent-ink); padding: .12em .38em; border-radius: 5px; font-size: .88em; }
.doc-content pre { background: var(--code-bg); color: var(--code-ink); border-radius: var(--radius);
  padding: 16px 18px; overflow-x: auto; font-size: .85rem; line-height: 1.6; }
.doc-content pre code { background: none; color: inherit; padding: 0; }
.doc-content table { border-collapse: collapse; width: 100%; margin: 1.4em 0; font-size: .91rem; display: block; overflow-x: auto; }
.doc-content th, .doc-content td { border: 1px solid var(--line); padding: 8px 12px; text-align: left; }
.doc-content th { background: var(--bg-alt); font-weight: 600; color: var(--ink); }
.doc-content img { max-width: 100%; }
.doc-content hr { border: 0; border-top: 1px solid var(--line); margin: 2.2em 0; }
.doc-content h2, .doc-content h3 { scroll-margin-top: 80px; }