Architecture page: numbered sections, bulleted TOC, clearer heading separation

Adds --number-sections to the pandoc invocation and rewrites the header
CSS so sections are visually separated from their titles:

- TOC gets real disc/circle bullets with nesting
- Each h1 starts with a top border and extra vertical rhythm
- h2 gets its own lighter divider
- Numbered sections (1, 2, 8.1, 8.2, ...) sit in a muted slot ahead of
  the title so the eye parses them as metadata, not as part of the
  heading text
- TOC has a "Contents" label above the list
- All colors still derived from the app palette (#f5f3ee background,
  #2e5b8a accent)

scripts/architecture-header.html

@@ -3,50 +3,92 @@
     --bg: #f5f3ee;
     --panel: #ffffff;
     --ink: #1a1a1a;
-    --ink-muted: #6b6b6b;
+    --ink-muted: #5a5a5a;
+    --ink-faint: #8a8a8a;
     --accent: #2e5b8a;
+    --accent-hover: #1f4470;
     --border: #e2ddd2;
+    --border-strong: #c9c2b0;
     --code-bg: #f0ede4;
   }
+  * { box-sizing: border-box; }
   html, body {
     background: var(--bg);
     color: var(--ink);
     font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
                  "Helvetica Neue", Arial, sans-serif;
     font-size: 16px;
-    line-height: 1.6;
+    line-height: 1.65;
     margin: 0;
   }
   body {
     max-width: 820px;
     margin: 0 auto;
-    padding: 48px 32px 96px;
+    padding: 56px 36px 120px;
   }
-  h1, h2, h3, h4 {
+
-    color: var(--ink);
+  /* Title block */
-    letter-spacing: -0.01em;
+  header#title-block-header {
-    line-height: 1.25;
+    margin: 0 0 12px;
-    margin-top: 2.2em;
+    padding-bottom: 28px;
-    margin-bottom: 0.6em;
+    border-bottom: 1px solid var(--border-strong);
   }
   h1.title {
-    font-size: 44px;
+    font-size: 48px;
     font-weight: 700;
-    margin-top: 0;
+    letter-spacing: -0.025em;
-    margin-bottom: 0.2em;
+    margin: 0 0 4px;
-    letter-spacing: -0.02em;
+    line-height: 1.1;
   }
-  h1 { font-size: 28px; font-weight: 700; border-bottom: 1px solid var(--border); padding-bottom: 0.3em; }
+  p.author, p.date { color: var(--ink-faint); margin: 0; font-size: 14px; }
-  h2 { font-size: 22px; font-weight: 600; }
+
-  h3 { font-size: 18px; font-weight: 600; color: var(--ink-muted); }
+  /* Headings -- clear hierarchy with real breathing room between sections */
+  h1, h2, h3, h4 {
+    color: var(--ink);
+    letter-spacing: -0.012em;
+    line-height: 1.25;
+  }
+  h1 {
+    font-size: 30px;
+    font-weight: 700;
+    margin: 3.2em 0 0.8em;
+    padding: 1.2em 0 0.5em;
+    border-top: 2px solid var(--border-strong);
+  }
+  h1:first-of-type { border-top: none; padding-top: 0; margin-top: 2em; }
+  h2 {
+    font-size: 22px;
+    font-weight: 600;
+    margin: 2.4em 0 0.6em;
+    padding-top: 0.4em;
+    border-top: 1px solid var(--border);
+  }
+  h3 {
+    font-size: 17px;
+    font-weight: 600;
+    color: var(--ink-muted);
+    margin: 1.8em 0 0.5em;
+  }
+  /* Section numbers sit in their own visual slot so the title reads cleanly */
+  .header-section-number {
+    display: inline-block;
+    color: var(--ink-faint);
+    font-weight: 500;
+    margin-right: 0.55em;
+    font-variant-numeric: tabular-nums;
+  }
+
+  /* Body text */
   p { margin: 0 0 1.1em; }
   a { color: var(--accent); text-decoration: none; }
-  a:hover { text-decoration: underline; }
+  a:hover { color: var(--accent-hover); text-decoration: underline; }
+
+  /* Inline + block code */
   code {
     font-family: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
     font-size: 0.88em;
     background: var(--code-bg);
-    padding: 0.1em 0.35em;
+    padding: 0.12em 0.4em;
     border-radius: 4px;
     border: 1px solid var(--border);
   }
@@ -54,10 +96,11 @@
     background: var(--panel);
     border: 1px solid var(--border);
     border-radius: 8px;
-    padding: 16px 20px;
+    padding: 18px 22px;
     overflow-x: auto;
-    font-size: 13.5px;
+    font-size: 13px;
     line-height: 1.55;
+    margin: 1.4em 0;
   }
   pre code {
     background: transparent;
@@ -66,39 +109,82 @@
     font-size: inherit;
   }
   .sourceCode { background: transparent; }
-  #TOC {
+
+  /* Table of contents -- real bullets, clear nesting */
+  nav#TOC {
     background: var(--panel);
     border: 1px solid var(--border);
-    border-radius: 8px;
+    border-radius: 10px;
-    padding: 20px 28px;
+    padding: 26px 36px 26px 28px;
-    margin: 28px 0 40px;
+    margin: 32px 0 48px;
   }
-  #TOC ul { list-style: none; padding-left: 1.1em; margin: 0.3em 0; }
+  nav#TOC::before {
-  #TOC > ul { padding-left: 0; }
+    content: "Contents";
-  #TOC li { margin: 0.25em 0; }
+    display: block;
-  #TOC a { color: var(--ink); }
+    font-size: 12px;
-  .mermaid, .diagram, figure {
+    text-transform: uppercase;
+    letter-spacing: 0.12em;
+    font-weight: 700;
+    color: var(--ink-faint);
+    margin-bottom: 14px;
+  }
+  nav#TOC ul {
+    list-style: disc;
+    padding-left: 1.35em;
+    margin: 0.35em 0;
+  }
+  nav#TOC > ul { padding-left: 1.1em; }
+  nav#TOC ul ul {
+    list-style: circle;
+    margin: 0.2em 0 0.35em;
+  }
+  nav#TOC li {
+    margin: 0.35em 0;
+    padding-left: 0.25em;
+    color: var(--ink-muted);
+  }
+  nav#TOC li::marker { color: var(--border-strong); }
+  nav#TOC a { color: var(--ink); }
+  nav#TOC a:hover { color: var(--accent); }
+  nav#TOC .toc-section-number {
+    color: var(--ink-faint);
+    font-variant-numeric: tabular-nums;
+    font-weight: 500;
+    margin-right: 0.45em;
+  }
+
+  /* Mermaid / figures */
+  figure, .mermaid, .diagram {
     background: var(--panel);
     border: 1px solid var(--border);
-    border-radius: 8px;
+    border-radius: 10px;
-    padding: 20px;
+    padding: 22px;
-    margin: 24px 0;
+    margin: 28px 0;
     text-align: center;
   }
   figure img, figure svg, p img { max-width: 100%; height: auto; }
+
+  /* Callouts */
   blockquote {
     border-left: 3px solid var(--accent);
-    margin: 1.2em 0;
+    margin: 1.3em 0;
-    padding: 0.2em 1em;
+    padding: 0.25em 1.1em;
     color: var(--ink-muted);
     background: var(--panel);
     border-radius: 0 6px 6px 0;
   }
-  header#title-block-header {
+
-    margin-bottom: 0.4em;
+  /* Body bullet lists (outside TOC) */
+  body > ul, body > ol,
+  h1 ~ ul, h1 ~ ol, h2 ~ ul, h2 ~ ol, h3 ~ ul, h3 ~ ol {
+    padding-left: 1.4em;
   }
+
   @media (max-width: 720px) {
-    body { padding: 28px 18px 72px; }
+    body { padding: 32px 20px 80px; }
-    h1.title { font-size: 34px; }
+    h1.title { font-size: 36px; }
+    h1 { font-size: 24px; }
+    h2 { font-size: 19px; }
+    nav#TOC { padding: 22px 26px; }
   }
 </style>

scripts/rebuild_architecture_html.sh

@@ -16,6 +16,7 @@ pandoc Bookly.lit.md \
   --filter mermaid-filter \
   --toc \
   --toc-depth=3 \
+  --number-sections \
   --highlight-style=tango \
   -H scripts/architecture-header.html \
   --metadata pagetitle="Bookly"