/* Topic-first navigation, extending the preserved original visual system. */
.masthead nav {flex:1;min-width:0;flex-wrap:wrap;justify-content:flex-end;gap:.15rem}
.masthead nav a{font-size:.88rem;padding:.6rem .7rem}
.masthead .wordmark{flex-shrink:0}
.breadcrumb-trail{font-size:.875rem;line-height:1.6;margin:0 0 1.25rem;display:flex;flex-wrap:wrap;gap:.4rem .6rem;align-items:baseline}
.breadcrumb-trail [aria-current]{color:var(--muted)}
.hub-intro{display:grid;grid-template-columns:minmax(0,1.35fr) minmax(240px,.65fr);gap:2rem;padding:2rem;margin-top:1.25rem;border:1px solid var(--line);border-radius:20px;background:rgba(247,251,255,.94);box-shadow:var(--shadow)}
.hub-intro h1{font-size:clamp(2rem,3.7vw,3rem);line-height:1.15;margin:0 0 1rem;max-width:22ch}
.hub-quick{border-left:1px solid var(--line);padding-left:1.5rem}
.hub-quick h2{font-size:1.2rem;margin:0 0 .7rem}
.hub-quick ul{padding-left:1.2rem;margin:0}.hub-quick li{margin:.6rem 0;line-height:1.55}
.hub-subjects{display:flex;gap:.4rem 1.5rem;flex-wrap:wrap;padding:1rem 1.25rem;margin:1rem 0 1.5rem;background:rgba(247,251,255,.94);border:1px solid var(--line);border-radius:14px}
.hub-subjects a{font-size:.9rem;font-weight:600;padding:.4rem 0}
.hub-search{border:1px solid var(--line);border-radius:14px;background:#f7fbff;padding:1.5rem;margin-bottom:1.5rem}
.hub-search h2{font-size:1.45rem;margin:0 0 .7rem}
.hub-search label{display:block;font-size:.9rem;font-weight:600;margin-bottom:.4rem}
.hub-search-row{display:grid;grid-template-columns:minmax(0,1fr) auto;gap:.65rem;max-width:760px}
.hub-search input{width:100%;min-width:0;min-height:46px;border:1px solid #87a8bf;border-radius:8px;padding:.65rem .8rem;font:1rem var(--sans);color:var(--ink);background:#fff}
.hub-search button{flex:0 0 auto;min-height:46px;padding:.5rem 1rem;border:1px solid #87a8bf;border-radius:999px;color:var(--brand-deep);background:#fff;font:600 .9rem var(--sans)}
.hub-search button:disabled{color:var(--muted);cursor:default}
#search-scope{font-size:.85rem;color:var(--muted);margin:.65rem 0 0;max-width:85ch}
#search-output{border-top:1px solid var(--line);margin-top:1rem;padding-top:1rem}
#search-status{font-weight:600;margin-bottom:.5rem}
#lesson-results{padding:0;list-style:none;margin:0;display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:.5rem 1.5rem}
#lesson-results li{padding:.65rem 0;border-bottom:1px solid var(--line);min-width:0}
#lesson-results small{display:block;color:var(--muted);font-size:.8rem;margin-bottom:.2rem}
#lesson-results a{display:block;font-weight:600}
#lesson-results p{font-size:.9rem;margin:.3rem 0 0;color:var(--muted)}
.hub-paths{margin:2rem 0}.hub-paths h2,.hub-topics>h2,.hub-tools>h2,.hub-glossary h2{font-size:1.8rem;margin:0 0 .7rem}
.hub-paths .path-grid{grid-template-columns:repeat(3,minmax(0,1fr));gap:1.25rem}
.hub-paths article{border-left:3px solid var(--brand);padding:.3rem 1rem;background:rgba(247,251,255,.65);min-width:0}
.hub-paths h3{font-size:1.2rem;margin:.3rem 0 .5rem}.hub-paths p,.hub-paths a{font-size:.95rem;line-height:1.65}.hub-paths p{margin-bottom:.5rem;color:var(--muted)}
.hub-topics{display:block;background:rgba(247,251,255,.96);border:1px solid var(--line);border-radius:18px;padding:2rem}
.topic-groups{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:.5rem 2.5rem;min-width:0}
.hub-note{color:var(--muted);font-size:.95rem;margin:0 0 1rem}
.topic-section{border-top:2px solid var(--line);padding:1.1rem 0;min-width:0;scroll-margin-top:1rem}
.topic-section h3{font-size:1.4rem;margin:0 0 .5rem}
.topic-section>p{font-size:.925rem;line-height:1.65;color:var(--muted);margin:0 0 .8rem}
.resource-list{list-style:none;padding:0;margin:0}.resource-list li{padding:.65rem 0;min-width:0}.resource-list a{font-size:1rem;font-weight:600;line-height:1.5}.resource-list p{font-size:.9rem;line-height:1.6;color:var(--muted);margin:.2rem 0 0}
.topic-note{font-size:.85rem!important;border-top:1px solid var(--line);padding-top:.7rem;margin-top:.7rem!important}
.workflow-route{padding-left:1.4rem;font-size:.95rem}.workflow-route li{margin:.55rem 0}
.symptom-links{display:flex;flex-direction:column;gap:.5rem}
.hub-tools,.hub-glossary{margin:1.5rem 0;padding:1.75rem;border:1px solid var(--line);border-radius:18px;background:rgba(247,251,255,.95)}
.hub-tools>.resource-list{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:1.5rem}
.hub-glossary p{max-width:78ch}
.anchor-alias{display:block;position:relative;scroll-margin-top:1rem;height:0}
.reference-intro{padding:1.75rem;margin-top:1.25rem;border:1px solid var(--line);border-radius:18px;background:rgba(247,251,255,.95)}
.reference-intro h1{font-size:clamp(2rem,4vw,3rem);margin:0 0 .8rem}
.reference-jumps{display:flex;gap:.5rem 1.5rem;flex-wrap:wrap;margin-top:1rem}
.reference-jumps a{padding:.4rem 0;font-size:.9rem}
.course-sequence{margin-top:1.5rem}.course-sequence p{font:700 .8rem var(--mono);color:var(--brand-deep);text-transform:uppercase;letter-spacing:.05em;margin-bottom:.5rem}
.course-sequence ol{list-style:none;display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:.5rem;padding:0;margin:0}
.course-sequence a{display:flex;gap:.45rem;padding:.75rem;border:1px solid var(--line);border-radius:9px;background:#fff;text-decoration:none;font-size:.85rem;line-height:1.45;height:100%}
.course-sequence a[aria-current]{background:var(--brand);color:#fff;border-color:var(--brand)}
.lesson-step-nav{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:1rem;border-top:1px solid var(--line);padding-top:1.25rem;margin-top:2rem}
.lesson-step-nav a{padding:.8rem 1rem;border:1px solid var(--line);border-radius:10px;background:#fff;font-size:.9rem}.lesson-step-nav small{display:block;font-size:.75rem;color:var(--muted);margin-bottom:.25rem}
@media(max-width:900px){.masthead{flex-wrap:wrap;justify-content:center}.masthead nav{flex-basis:100%;justify-content:center}.hub-intro{grid-template-columns:1fr;gap:1rem}.hub-quick{border-left:0;border-top:1px solid var(--line);padding:1rem 0 0}.hub-quick ul{display:flex;flex-wrap:wrap;gap:.25rem 2rem}.topic-groups{gap:.5rem 1.5rem}.hub-paths .path-grid{gap:1rem}.course-sequence ol{grid-template-columns:repeat(2,minmax(0,1fr))}}
@media(max-width:620px){.masthead nav a{font-size:.8rem;padding:.5rem .45rem}.hub-intro,.hub-topics,.hub-tools,.hub-glossary,.reference-intro{padding:1.2rem}.hub-intro h1{font-size:2rem}.hub-quick ul{display:block}.hub-subjects{gap:.3rem 1rem;padding:.75rem 1rem}.hub-subjects a{font-size:.85rem}.hub-search{padding:1.2rem}#lesson-results,.hub-paths .path-grid,.topic-groups,.hub-tools>.resource-list{grid-template-columns:minmax(0,1fr)}.hub-paths article{padding:.35rem 1rem}.hub-topics{gap:0}.lesson-step-nav{grid-template-columns:1fr}.course-sequence a{font-size:.8rem;padding:.6rem}.reference-jumps{gap:.25rem 1rem}}
@media print{.masthead,.hub-search,.hub-subjects,.breadcrumb-trail,.course-sequence,.lesson-step-nav{display:none}.hub-topics{display:block}.hub-intro{display:block}}