/* Theory / data / about pages. */
.sectionPage { max-width: 1120px; margin: 0 auto; padding: 18px 20px 40px; }
.sectionPage h1 { font-size: 26px; margin: 4px 0 6px; }
.sectionPage h2 { font-size: 18px; margin: 26px 0 8px; color: var(--accent); }
.sectionPage h3 { font-size: 15px; margin: 14px 0 6px; }
.sectionPage p, .sectionPage li { color: var(--text-2); line-height: 1.7; }
.lead { color: var(--text-2); max-width: 860px; line-height: 1.65; }
.toc { display: flex; flex-wrap: wrap; gap: 6px; margin: 10px 0 4px; }
.toc a { border: 1px solid var(--border-strong); border-radius: 100px; padding: 3px 10px; font-size: 12px; text-decoration: none; transition: border-color .15s, background-color .15s; }
.toc a:hover { border-color: var(--accent); background: var(--panel-2); }
.formula { background: var(--bg-2); border: 1px solid var(--border); border-radius: 8px; padding: 10px 14px; margin: 8px 0; font-family: "Cambria Math", "STIX Two Math", Georgia, serif; font-size: 16px; overflow-x: auto; color: var(--text); }
.formula .lbl { font-family: var(--font); font-size: 11px; color: var(--muted); display: block; margin-top: 4px; }
.diagram { background: var(--panel); border: 1px solid var(--border); border-radius: 10px; padding: 10px; margin: 10px 0; }
.diagram svg { width: 100%; height: auto; display: block; }
.diagram figcaption { font-size: 12px; color: var(--muted); margin-top: 6px; }
.cardgrid { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 12px; }
.featurecard { border-radius: 12px; border: 1px solid var(--border); background: var(--panel); padding: 16px; line-height: 1.6; }
.featurecard h3 { margin: 0 0 6px; color: var(--accent); font-size: 15px; }
.featurecard p { font-size: 13px; color: var(--text-2); margin: 0; }
.tag { display: inline-block; border: 1px solid var(--border-strong); border-radius: 100px; padding: 2px 9px; font-size: 11.5px; color: var(--accent); margin: 6px 4px 0 0; text-decoration: none; transition: border-color .15s, background-color .15s; }
.tag:hover { border-color: var(--accent); background: var(--panel-2); }
.aboutHero { display: flex; align-items: center; gap: 22px; border: 1px solid var(--border-strong); border-radius: 14px; padding: 22px; background: linear-gradient(110deg, var(--panel-3), var(--panel)); margin-bottom: 16px; flex-wrap: wrap; }
.aboutHero img { height: 70px; width: auto; background: #fff; border-radius: 10px; padding: 6px; }
.aboutHero h1 { font-size: 32px; margin: 0; }
.dropzone { border: 2px dashed var(--border-strong); border-radius: 14px; min-height: 130px; display: grid; place-items: center; text-align: center; padding: 18px; background: var(--panel); cursor: pointer; margin: 12px 0 16px; }
.dropzone:hover, .dropzone.dragover { border-color: var(--accent); background: var(--panel-2); }
.dropzone strong { font-size: 16px; }
.roadmap { counter-reset: r; list-style: none; padding: 0; display: grid; gap: 8px; }
.roadmap li { border-left: 3px solid var(--accent); background: var(--panel); padding: 8px 12px; border-radius: 6px; }
/* Theory page: reading paths, contents grouped by part, part labels (text elements added Nov 2026). */
.th-read { max-width: 860px; margin: 0 0 22px; padding: 2px 0 2px 14px; border-left: 3px solid var(--accent); }
.sectionPage .th-read p { margin: 4px 0; }
.toc.toc-parts { display: grid; gap: 8px; }
.toc-group { display: flex; flex-wrap: wrap; gap: 6px; align-items: center; min-width: 0; }
.toc-part { flex: 0 0 230px; font-size: 12px; color: var(--muted); }
.th-part { margin: 56px 0 0; padding-top: 18px; border-top: 1px solid var(--border); }
.th-part-k { display: block; font-size: 12px; letter-spacing: .08em; text-transform: uppercase; color: var(--accent); }
.th-part-t { display: block; font-size: 20px; font-weight: 700; color: var(--text); margin-top: 2px; }
.sectionPage .th-part p { margin: 2px 0 0; max-width: 720px; color: var(--muted); }
.sectionPage .th-part + section h2 { margin-top: 20px; }
@media (max-width: 720px) { .toc-part { flex-basis: 100%; } }
.sectionPage .th-read ol { margin: 4px 0 8px; padding-left: 20px; }
.sectionPage .th-read li { line-height: 1.55; }
.th-more { margin: 14px 0 0; border: 1px solid var(--border); border-radius: 10px; background: var(--panel); min-width: 0; }
.th-more > summary { cursor: pointer; padding: 10px 14px; font-size: 13px; font-weight: 600; color: var(--accent); }
.th-more[open] > summary { border-bottom: 1px solid var(--border); }
.th-more-body { padding: 6px 14px 12px; min-width: 0; }