:root {
  --bg: #0b1020;
  --bg-soft: #121a30;
  --bg-card: #16203a;
  --border: #263453;
  --text: #e8edf7;
  --text-dim: #93a1c0;
  --accent: #f59e0b;
  --blue: #3b82f6;
  --green: #10b981;
  --purple: #8b5cf6;
  --red: #ef4444;
  --radius: 14px;
}
* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; background: var(--bg); color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Segoe UI", sans-serif; }
body { min-height: 100vh; display: flex; flex-direction: column; }

/* Header */
.app-header { display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap; gap: 12px;
  padding: 14px 24px; background: linear-gradient(180deg, #101a33, #0d1428); border-bottom: 1px solid var(--border);
  position: sticky; top: 0; z-index: 50; }
.brand { display: flex; align-items: center; gap: 12px; }
.brand-icon { font-size: 30px; color: var(--accent); filter: drop-shadow(0 0 8px rgba(245,158,11,.5)); }
.brand h1 { font-size: 20px; margin: 0; letter-spacing: 1px; }
.subtitle { margin: 2px 0 0; font-size: 12px; color: var(--text-dim); }
.tabs { display: flex; gap: 6px; background: rgba(255,255,255,.04); padding: 5px; border-radius: 12px; }
.tab { border: 0; background: transparent; color: var(--text-dim); padding: 8px 18px; border-radius: 9px;
  cursor: pointer; font-size: 14px; transition: all .2s; }
.tab:hover { color: var(--text); }
.tab.active { background: var(--accent); color: #1a1206; font-weight: 600; }

main { flex: 1; padding: 18px 24px 28px; max-width: 1500px; width: 100%; margin: 0 auto; }
.view { display: none; animation: fadeIn .35s ease; }
.view.active { display: block; }
@keyframes fadeIn { from { opacity: 0; transform: translateY(6px); } to { opacity: 1; transform: none; } }

/* Graph */
.graph-toolbar { display: flex; align-items: center; gap: 12px; flex-wrap: wrap; margin-bottom: 12px; }
.search-box { background: var(--bg-card); border: 1px solid var(--border); color: var(--text);
  padding: 8px 14px; border-radius: 10px; width: 220px; font-size: 14px; outline: none; }
.search-box:focus { border-color: var(--accent); }
.chip-row { display: flex; gap: 6px; flex-wrap: wrap; }
.chip { border: 1px solid var(--border); background: var(--bg-card); color: var(--text-dim);
  padding: 5px 12px; border-radius: 999px; font-size: 12px; cursor: pointer; transition: all .2s; }
.chip.on { color: #0b1020; font-weight: 600; }
.chip.off { opacity: .45; }
.level-filter { display: flex; gap: 8px; font-size: 12px; color: var(--text-dim); }
.level-filter label { display: flex; gap: 4px; align-items: center; cursor: pointer; }
.path-select, .mini-btn { background: var(--bg-card); border: 1px solid var(--border); color: var(--text);
  padding: 7px 12px; border-radius: 10px; font-size: 13px; cursor: pointer; }
.mini-btn:hover, .path-select:hover { border-color: var(--accent); }
.graph-wrap { position: relative; height: calc(100vh - 240px); min-height: 480px;
  border: 1px solid var(--border); border-radius: var(--radius); overflow: hidden; background: radial-gradient(ellipse at 30% 20%, #101c38 0%, #0b1020 70%); }
#graph-canvas { width: 100%; height: 100%; }
.graph-stats { margin-top: 10px; font-size: 13px; color: var(--text-dim); display: flex; gap: 18px; }
.graph-stats b { color: var(--accent); }

.concept-panel { position: absolute; top: 14px; right: 14px; width: 340px; max-height: calc(100% - 28px);
  overflow-y: auto; background: rgba(13,20,40,.96); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 18px; backdrop-filter: blur(8px); box-shadow: 0 12px 40px rgba(0,0,0,.5); z-index: 10;
  animation: slideIn .25s ease; }
@keyframes slideIn { from { transform: translateX(30px); opacity: 0; } to { transform: none; opacity: 1; } }
.hidden { display: none !important; }
.panel-close { position: absolute; top: 10px; right: 12px; background: none; border: 0; color: var(--text-dim);
  font-size: 22px; cursor: pointer; }
.panel-close:hover { color: var(--text); }
.concept-panel h2 { font-size: 18px; margin: 0 0 2px; padding-right: 24px; }
.concept-panel .en { color: var(--text-dim); font-size: 13px; margin: 0 0 10px; }
.badge-row { display: flex; gap: 6px; flex-wrap: wrap; margin-bottom: 10px; }
.badge { font-size: 11px; padding: 3px 9px; border-radius: 999px; border: 1px solid var(--border); color: var(--text-dim); }
.badge.chapter { color: var(--accent); border-color: rgba(245,158,11,.4); }
.stars { color: var(--accent); font-size: 12px; letter-spacing: 2px; }
.concept-panel .desc { font-size: 13.5px; line-height: 1.75; color: #cdd7ec; margin: 10px 0; }
.formula { background: #0a1226; border: 1px solid #24406e; border-left: 3px solid var(--blue); color: #7cc3ff;
  font-family: "SF Mono", Menlo, Consolas, monospace; padding: 9px 12px; border-radius: 8px; font-size: 13px; margin: 10px 0; }
.tag { font-size: 11px; background: rgba(59,130,246,.15); color: #7cc3ff; padding: 2px 8px; border-radius: 6px; }
.link-list { margin-top: 12px; border-top: 1px solid var(--border); padding-top: 10px; }
.link-list h4 { margin: 0 0 8px; font-size: 12px; color: var(--text-dim); text-transform: uppercase; letter-spacing: 1px; }
.link-item { display: block; width: 100%; text-align: left; background: none; border: 0; color: #a8c1f5;
  font-size: 13px; padding: 5px 6px; border-radius: 6px; cursor: pointer; }
.link-item:hover { background: rgba(59,130,246,.12); }
.link-item .rel { color: var(--text-dim); font-size: 11px; margin-right: 6px; }
.src-note { font-size: 11px; color: var(--text-dim); margin-top: 10px; }

/* System view */
.section-title { font-size: 17px; margin: 26px 0 12px; display: flex; align-items: center; gap: 8px; }
.section-title::before { content: ""; width: 4px; height: 18px; background: var(--accent); border-radius: 2px; }
.pillar-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(230px, 1fr)); gap: 12px; }
.pillar-card { border-radius: var(--radius); padding: 16px; background: var(--bg-card); border: 1px solid var(--border);
  border-top: 3px solid var(--pc, #888); transition: transform .2s; }
.pillar-card:hover { transform: translateY(-3px); }
.pillar-card h3 { margin: 0 0 4px; font-size: 15px; color: var(--pc); }
.pillar-card .en { font-size: 11px; color: var(--text-dim); }
.pillar-card p { font-size: 12.5px; color: var(--text-dim); line-height: 1.6; margin: 8px 0 6px; }
.pillar-card .count { font-size: 12px; color: var(--text); }

.path-flow { background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 16px 18px; margin-bottom: 14px; }
.path-flow h3 { margin: 0 0 4px; font-size: 15px; }
.path-flow .path-desc { font-size: 12.5px; color: var(--text-dim); margin: 0 0 12px; line-height: 1.6; }
.step-row { display: flex; flex-wrap: wrap; align-items: center; gap: 6px; }
.step-chip { display: inline-flex; align-items: center; gap: 6px; background: var(--bg-soft);
  border: 1px solid var(--border); color: var(--text); font-size: 12.5px; padding: 6px 11px;
  border-radius: 999px; cursor: pointer; transition: all .15s; }
.step-chip:hover { border-color: var(--accent); color: var(--accent); }
.step-num { display: inline-flex; width: 18px; height: 18px; border-radius: 50%; background: var(--accent);
  color: #1a1206; font-size: 10.5px; font-weight: 700; align-items: center; justify-content: center; }
.step-arrow { color: var(--text-dim); font-size: 12px; }

.chapter-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(330px, 1fr)); gap: 14px; }
.chapter-card { background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius); padding: 18px; }
.chapter-card .ch-num { font-size: 12px; color: var(--accent); font-weight: 700; letter-spacing: 1px; }
.chapter-card h3 { margin: 4px 0 2px; font-size: 16px; }
.chapter-card .en { font-size: 12px; color: var(--text-dim); margin: 0 0 10px; }
.chapter-card .summary { font-size: 13px; line-height: 1.75; color: #cdd7ec; }
.chapter-card ul { margin: 10px 0 0; padding-left: 18px; }
.chapter-card li { font-size: 12.5px; color: var(--text-dim); line-height: 1.8; }

.glossary-table { width: 100%; border-collapse: collapse; font-size: 13px; }
.glossary-table th, .glossary-table td { border: 1px solid var(--border); padding: 8px 12px; text-align: left; }
.glossary-table th { background: var(--bg-soft); color: var(--accent); }
.glossary-table td:first-child { font-family: Menlo, monospace; color: #7cc3ff; white-space: nowrap; }

/* Lab */
.lab-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(420px, 1fr)); gap: 16px; }
.lab-card { background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius); padding: 18px; }
.lab-card.wide { grid-column: 1 / -1; }
.lab-card h3 { margin: 0 0 4px; font-size: 15.5px; }
.lab-desc { font-size: 12.5px; color: var(--text-dim); margin: 0 0 14px; }
.sim-body canvas { width: 100%; border-radius: 10px; background: #0a1226; display: block; }
.slider-row { display: grid; grid-template-columns: 92px 1fr 74px; gap: 10px; align-items: center;
  margin: 8px 0; font-size: 13px; }
.slider-row output { text-align: right; color: var(--accent); font-family: Menlo, monospace; font-size: 12.5px; }
input[type="range"] { -webkit-appearance: none; height: 4px; background: var(--border); border-radius: 2px; outline: none; }
input[type="range"]::-webkit-slider-thumb { -webkit-appearance: none; width: 15px; height: 15px; border-radius: 50%;
  background: var(--accent); cursor: pointer; box-shadow: 0 0 8px rgba(245,158,11,.6); }
.sim-readout { display: flex; gap: 22px; margin: 12px 0; }
.readout-item { font-size: 13px; }
.readout-item b { display: block; font-size: 22px; color: var(--accent); font-family: Menlo, monospace; }
.toggle-btn { background: var(--bg-soft); border: 1px solid var(--border); color: var(--text);
  padding: 7px 16px; border-radius: 999px; font-size: 13px; cursor: pointer; transition: all .2s; }
.toggle-btn.on { background: var(--green); border-color: var(--green); color: #06281c; font-weight: 600; }
.preset-row { display: flex; gap: 6px; margin: 6px 0 2px; flex-wrap: wrap; }
.preset-btn { background: var(--bg-soft); border: 1px solid var(--border); color: var(--text-dim);
  font-size: 11.5px; padding: 4px 10px; border-radius: 7px; cursor: pointer; }
.preset-btn.on { color: var(--accent); border-color: var(--accent); }

.flow-steps { display: flex; gap: 8px; flex-wrap: wrap; margin-top: 12px; }
.flow-step { flex: 1 1 130px; min-width: 130px; background: var(--bg-soft); border: 1px solid var(--border);
  border-radius: 12px; padding: 12px; transition: all .35s; position: relative; }
.flow-step .n { font-size: 11px; color: var(--text-dim); }
.flow-step h4 { margin: 3px 0 5px; font-size: 13.5px; }
.flow-step p { margin: 0; font-size: 11.5px; color: var(--text-dim); line-height: 1.55; }
.flow-step.active { border-color: var(--accent); background: rgba(245,158,11,.1); transform: translateY(-4px);
  box-shadow: 0 8px 24px rgba(245,158,11,.18); }

/* Sources */
.source-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); gap: 14px; margin-bottom: 24px; }
.source-card { background: var(--bg-card); border: 1px solid var(--border); border-left: 4px solid var(--sc, #888);
  border-radius: var(--radius); padding: 18px; }
.source-card h3 { margin: 0 0 3px; font-size: 15.5px; }
.source-card .en { font-size: 12px; color: var(--text-dim); }
.source-meta { display: flex; gap: 14px; margin-top: 12px; flex-wrap: wrap; }
.source-meta div { font-size: 12px; color: var(--text-dim); }
.source-meta b { display: block; font-size: 17px; color: var(--text); font-family: Menlo, monospace; }
.source-card.placeholder { border: 1.5px dashed var(--border); border-left: 4px dashed var(--border);
  background: transparent; display: flex; align-items: center; justify-content: center; min-height: 130px;
  color: var(--text-dim); font-size: 14px; }
.guide { background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius); padding: 20px; }
.guide h3 { margin-top: 0; }
.guide ol { padding-left: 20px; }
.guide li { font-size: 13.5px; line-height: 2; color: #cdd7ec; }
.guide code { background: #0a1226; padding: 2px 7px; border-radius: 5px; color: #7cc3ff; font-size: 12.5px; }
.guide pre { background: #0a1226; border: 1px solid var(--border); border-radius: 10px; padding: 14px;
  overflow-x: auto; font-size: 12px; line-height: 1.6; color: #a8c1f5; }

/* Modal */
.modal { position: fixed; inset: 0; background: rgba(4,8,18,.75); display: flex; align-items: center;
  justify-content: center; z-index: 100; backdrop-filter: blur(4px); }
.modal-card { position: relative; width: min(520px, 92vw); max-height: 84vh; overflow-y: auto;
  background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius); padding: 22px; }

/* Loading */
.loading { position: fixed; inset: 0; background: var(--bg); display: flex; flex-direction: column;
  align-items: center; justify-content: center; z-index: 200; gap: 14px; color: var(--text-dim); }
.spinner { width: 42px; height: 42px; border: 3px solid var(--border); border-top-color: var(--accent);
  border-radius: 50%; animation: spin 0.9s linear infinite; }
@keyframes spin { to { transform: rotate(360deg); } }

@media (max-width: 760px) {
  main { padding: 12px; }
  .concept-panel { width: calc(100% - 28px); }
  .graph-wrap { height: 70vh; }
}

/* Formula detail & examples（概念深化） */
.formula-detail { margin: 10px 0; }
.formula-vars { width: 100%; border-collapse: collapse; font-size: 12px; margin: 6px 0 8px; }
.formula-vars th, .formula-vars td { padding: 6px 10px; border-bottom: 1px solid var(--border);
  text-align: left; vertical-align: top; line-height: 1.55; }
.formula-vars th { color: var(--text-dim); font-weight: 500; font-size: 11px; }
.formula-vars .sym { font-family: Menlo, monospace; color: #7cc3ff; white-space: nowrap; }
.formula-vars .typ { color: var(--text-dim); }
.intuition { background: rgba(59,130,246,.1); border-left: 3px solid #3b82f6; padding: 8px 12px;
  border-radius: 0 8px 8px 0; font-size: 12.5px; line-height: 1.7; margin: 8px 0; color: #cdd7ec; }
.example-block { background: rgba(16,185,129,.1); border-left: 3px solid #10b981; padding: 8px 12px;
  border-radius: 0 8px 8px 0; margin: 8px 0; font-size: 12.5px; line-height: 1.75; color: #cdd7ec; }
.example-block .ex-title { font-weight: 600; color: #34d399; margin-bottom: 3px; }
.row-label { font-size: 11.5px; color: var(--text-dim); align-self: center; }
.topic-row { margin-top: 2px; }
.topic-chip { background: transparent; border: 1px solid var(--accent); color: var(--accent);
  border-radius: 999px; padding: 3px 12px; font-size: 12px; cursor: pointer; transition: all .2s; }
.topic-chip:hover { background: var(--accent); color: #0b1020; }

/* Topics（专题深化） */
.topic-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); gap: 14px; margin-bottom: 24px; }
.topic-card { background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 16px; cursor: pointer; transition: all .2s; }
.topic-card:hover { transform: translateY(-3px); border-color: var(--accent);
  box-shadow: 0 10px 28px rgba(245,158,11,.12); }
.t-head { display: flex; gap: 12px; align-items: center; }
.t-icon { font-size: 24px; }
.t-head h3 { margin: 0; font-size: 15px; }
.t-head .en { font-size: 11px; color: var(--text-dim); margin: 2px 0 0; }
.t-desc { font-size: 12.5px; color: #cdd7ec; line-height: 1.65; margin: 10px 0; }
.t-foot { display: flex; justify-content: space-between; align-items: center; gap: 8px; }
.t-count { font-size: 11.5px; color: var(--text-dim); white-space: nowrap; }

/* Topic modal */
.modal-card.wide { width: min(720px, 94vw); }
.topic-modal-content .sec-h { margin: 18px 0 6px; font-size: 14.5px; color: var(--accent); }
.topic-modal-content .sec-b { font-size: 13px; line-height: 1.8; color: #cdd7ec; margin: 0 0 4px; }
.topic-modal-content .step-row { margin-top: 8px; }