/* ============================================================
   topic-styles.css — shared styles for all topic & demo pages
   ============================================================ */

/* reuse root vars from styles.css */

/* ---- Topic Navbar ---- */
.t-nav {
  position: sticky; top: 0; z-index: 99;
  height: 56px; display: flex; align-items: center;
  background: rgba(7,7,13,.9); backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border);
  padding: 0 20px; gap: 16px;
}
.t-nav-logo { display:flex; align-items:center; gap:7px; text-decoration:none; font-family:var(--fdsp); font-size:1.1rem; font-weight:600; color:var(--text); }
.t-nav-logo strong { color:var(--accent2); }
.t-nav-logo .logo-icon { background:var(--grad); -webkit-background-clip:text; -webkit-text-fill-color:transparent; }
.t-nav-links { display:flex; gap:4px; flex:1; }
.t-nav-links a { padding:5px 11px; border-radius:var(--r-sm); text-decoration:none; color:var(--text2); font-size:.83rem; font-weight:500; transition:color .15s,background .15s; }
.t-nav-links a:hover { color:var(--text); background:var(--surf); }
.t-nav-right { margin-left:auto; display:flex; gap:8px; align-items:center; }

/* ---- Breadcrumb ---- */
.breadcrumb { padding:14px 0 0; }
.breadcrumb-inner { display:flex; align-items:center; gap:6px; font-size:.78rem; color:var(--text2); }
.breadcrumb-inner a { color:var(--text2); text-decoration:none; }
.breadcrumb-inner a:hover { color:var(--text); }
.breadcrumb-inner svg { width:12px; height:12px; flex-shrink:0; }

/* ---- Topic Hero ---- */
.t-hero {
  padding: 44px 0 40px;
  background: var(--bg);
  border-bottom: 1px solid var(--border);
  position: relative; overflow: hidden;
}
.t-hero::before {
  content:''; position:absolute; inset:0;
  background: radial-gradient(ellipse 60% 80% at 50% 0%, rgba(99,102,241,.12), transparent);
  pointer-events:none;
}
.t-hero-inner { position:relative; max-width:860px; }
.t-hero-tag {
  display:inline-flex; align-items:center; gap:6px;
  background:rgba(99,102,241,.1); border:1px solid rgba(99,102,241,.22);
  color:var(--accent2); padding:4px 12px; border-radius:100px;
  font-size:.72rem; font-weight:700; text-transform:uppercase; letter-spacing:.07em;
  margin-bottom:16px;
}
.t-hero h1 {
  font-family:var(--fdsp); font-size:clamp(1.8rem,4vw,2.8rem); font-weight:700;
  color:#f0f0ff; letter-spacing:-.02em; margin-bottom:14px; line-height:1.2;
}
[data-theme="light"] .t-hero h1 { color:#111120; }
.t-hero-desc { font-size:1rem; color:var(--text2); max-width:620px; line-height:1.7; margin-bottom:24px; }
.t-hero-stats { display:flex; gap:28px; flex-wrap:wrap; }
.t-stat { }
.t-stat strong { display:block; font-family:var(--fdsp); font-size:1.3rem; font-weight:700; color:var(--text); }
.t-stat span { font-size:.75rem; color:var(--text2); }

/* ---- Two-col layout ---- */
.t-layout { display:grid; grid-template-columns:220px 1fr; gap:32px; padding:40px 0 80px; align-items:start; }
@media(max-width:768px){ .t-layout { grid-template-columns:1fr; } }

/* ---- TOC Sidebar ---- */
.t-toc {
  position:sticky; top:72px;
  background:var(--surf); border:1px solid var(--border);
  border-radius:var(--r); padding:16px; font-size:.83rem;
}
.t-toc h4 { font-family:var(--fdsp); font-size:.78rem; font-weight:700; text-transform:uppercase; letter-spacing:.07em; color:var(--text2); margin-bottom:12px; }
.t-toc ul { list-style:none; display:flex; flex-direction:column; gap:2px; }
.t-toc ul a { display:block; padding:5px 8px; border-radius:var(--r-sm); color:var(--text2); text-decoration:none; transition:color .15s, background .15s; }
.t-toc ul a:hover, .t-toc ul a.active { color:var(--accent2); background:rgba(99,102,241,.08); }
@media(max-width:768px){ .t-toc { display:none; } }

/* ---- Content body ---- */
.t-body { min-width:0; }

.t-section { margin-bottom:48px; scroll-margin-top:76px; }
.t-section h2 {
  font-family:var(--fdsp); font-size:1.4rem; font-weight:700;
  color:var(--text); margin-bottom:16px; padding-bottom:10px;
  border-bottom:1px solid var(--border); letter-spacing:-.01em;
}
.t-section h3 { font-family:var(--fdsp); font-size:1.05rem; font-weight:600; color:var(--text); margin:20px 0 10px; }
.t-section p { font-size:.92rem; color:var(--text2); line-height:1.75; margin-bottom:12px; }
.t-section ul, .t-section ol { padding-left:20px; margin-bottom:12px; }
.t-section li { font-size:.9rem; color:var(--text2); line-height:1.7; margin-bottom:4px; }
.t-section strong { color:var(--text); font-weight:600; }

/* ---- Info box ---- */
.info-box {
  background:rgba(99,102,241,.07); border:1px solid rgba(99,102,241,.2);
  border-radius:var(--r); padding:16px 20px; margin-bottom:16px;
}
.info-box.tip   { background:rgba(16,185,129,.07); border-color:rgba(16,185,129,.2); }
.info-box.warn  { background:rgba(245,158,11,.07);  border-color:rgba(245,158,11,.2); }
.info-box p { margin:0; font-size:.87rem; }

/* ---- Concept cards grid ---- */
.concept-grid { display:grid; grid-template-columns:repeat(auto-fill,minmax(200px,1fr)); gap:12px; margin-bottom:16px; }
.concept-card {
  background:var(--surf); border:1px solid var(--border);
  border-radius:var(--r); padding:16px;
  transition:border-color .2s, transform .2s var(--ease);
}
.concept-card:hover { border-color:var(--border2); transform:translateY(-2px); }
.concept-card h4 { font-family:var(--fdsp); font-size:.88rem; font-weight:600; color:var(--accent2); margin-bottom:6px; }
.concept-card p { font-size:.8rem; color:var(--text2); line-height:1.6; margin:0; }

/* ---- Algorithm / comparison table ---- */
.t-table { width:100%; border-collapse:collapse; font-size:.85rem; margin-bottom:20px; }
.t-table th { background:var(--surf2); color:var(--text); font-weight:600; padding:10px 14px; text-align:left; border-bottom:1px solid var(--border); }
.t-table td { padding:9px 14px; border-bottom:1px solid var(--border); color:var(--text2); }
.t-table tr:last-child td { border-bottom:none; }
.t-table tr:hover td { background:var(--surf); }
.t-table-wrap { overflow-x:auto; border:1px solid var(--border); border-radius:var(--r); margin-bottom:20px; }

/* ---- Code block ---- */
.code-block {
  background:#0d0d18; border:1px solid var(--border);
  border-radius:var(--r); overflow:hidden; margin-bottom:20px;
}
.code-block-header {
  display:flex; align-items:center; justify-content:space-between;
  padding:8px 14px; background:var(--surf2);
  border-bottom:1px solid var(--border); font-size:.76rem;
}
.code-lang { color:var(--accent2); font-weight:600; font-family:var(--fdsp); }
.code-copy { background:none; border:none; color:var(--text2); cursor:pointer; font-size:.76rem; padding:2px 8px; border-radius:4px; transition:color .15s; }
.code-copy:hover { color:var(--text); }
.code-block pre { margin:0; padding:16px; overflow-x:auto; font-size:.83rem; line-height:1.65; font-family:'Fira Code','Cascadia Code',monospace; }
.code-block code { color:#c9d1d9; }
.kw { color:#ff7b72; } /* keywords */
.fn { color:#d2a8ff; } /* functions */
.st { color:#a5d6ff; } /* strings */
.cm { color:#8b949e; } /* comments */
.nm { color:#f0883e; } /* numbers */
.cn { color:#79c0ff; } /* class/type names */

/* ---- Visual diagram ---- */
.diagram {
  background:var(--surf); border:1px solid var(--border);
  border-radius:var(--r); padding:24px; margin-bottom:20px;
  overflow-x:auto;
}
.flow { display:flex; align-items:center; gap:0; flex-wrap:wrap; justify-content:center; }
.flow-box {
  background:var(--surf2); border:1px solid var(--border2);
  border-radius:var(--r-sm); padding:10px 16px;
  font-size:.82rem; font-weight:500; color:var(--text); text-align:center; white-space:nowrap;
}
.flow-box.accent { background:rgba(99,102,241,.15); border-color:rgba(99,102,241,.35); color:var(--accent2); }
.flow-box.green  { background:rgba(16,185,129,.12); border-color:rgba(16,185,129,.3);  color:#34d399; }
.flow-box.amber  { background:rgba(245,158,11,.12);  border-color:rgba(245,158,11,.3);  color:#fbbf24; }
.flow-box.red    { background:rgba(244,63,94,.12);   border-color:rgba(244,63,94,.3);   color:#fb7185; }
.flow-arrow { color:var(--text2); padding:0 8px; font-size:1.1rem; flex-shrink:0; }

/* ---- Tags / chips (topic page) ---- */
.t-chips { display:flex; gap:6px; flex-wrap:wrap; margin-bottom:16px; }
.t-chip { font-size:.75rem; background:var(--surf2); border:1px solid var(--border); color:var(--text2); padding:3px 10px; border-radius:100px; }

/* ---- Related topics ---- */
.related-grid { display:grid; grid-template-columns:repeat(auto-fill,minmax(200px,1fr)); gap:12px; }
.related-card {
  background:var(--surf); border:1px solid var(--border);
  border-radius:var(--r); padding:16px; text-decoration:none;
  transition:border-color .2s, transform .2s var(--ease), box-shadow .2s;
  display:block;
}
.related-card:hover { border-color:var(--border2); transform:translateY(-2px); box-shadow:var(--sh); }
.related-cat { font-size:.68rem; font-weight:700; text-transform:uppercase; letter-spacing:.05em; color:var(--accent2); margin-bottom:6px; }
.related-card h4 { font-family:var(--fdsp); font-size:.9rem; font-weight:600; color:var(--text); margin-bottom:4px; }
.related-card p { font-size:.78rem; color:var(--text2); margin:0; line-height:1.5; }

/* ---- Responsive tweaks ---- */
@media(max-width:600px){
  .t-hero h1 { font-size:1.7rem; }
  .t-hero-stats { gap:16px; }
  .concept-grid { grid-template-columns:1fr 1fr; }
  .related-grid { grid-template-columns:1fr 1fr; }
}