:root{--navy:#17243d;--blue:#315ee8;--sky:#eaf1ff;--orange:#ff7a45;--purple:#7c60da;--ink:#17233a;--muted:#657089;--line:#e6eaf1;--paper:#f5f7fb;--shadow:0 24px 70px rgba(27,45,88,.12)}*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-snap-type:y proximity}body{margin:0;background:var(--paper);color:var(--ink);font-family:-apple-system,BlinkMacSystemFont,"PingFang SC","Microsoft YaHei",sans-serif}button,select{font:inherit}.topbar{height:70px;position:fixed;z-index:80;inset:0 0 auto;background:rgba(255,255,255,.92);backdrop-filter:blur(18px);border-bottom:1px solid rgba(20,34,61,.08);display:flex;align-items:center;padding:0 24px;gap:22px}.brand{font-weight:950;white-space:nowrap;text-decoration:none;color:var(--ink)}.brand-mark{display:inline-grid;place-items:center;width:28px;height:28px;border-radius:9px;background:var(--blue);color:#fff;margin-right:8px}.product-tabs{display:flex;gap:4px;justify-content:center;flex:1}.product-tabs button{border:0;background:transparent;padding:10px 13px;border-radius:12px;color:#717b91;font-weight:750}.product-tabs .active{background:var(--sky);color:var(--blue)}.tour-tools{display:flex;gap:7px;align-items:center;font-size:13px;color:#53607a}.tour-tools select{border:1px solid var(--line);background:#fff;border-radius:8px;padding:5px}.tour-button{border:1px solid var(--navy);background:var(--navy);color:#fff;border-radius:10px;padding:9px 12px;font-weight:800;cursor:pointer}.tour-button.playing{background:var(--orange);border-color:var(--orange)}.mobile-menu{display:none}.sidebar{position:fixed;z-index:70;left:21px;top:50%;transform:translateY(-50%);width:194px;padding:14px;background:rgba(255,255,255,.88);backdrop-filter:blur(12px);border:1px solid #e7ecf6;border-radius:18px;box-shadow:0 16px 40px rgba(35,56,100,.1)}.side-title{font-size:11px;font-weight:900;color:#96a0b3;letter-spacing:.1em;margin:6px 8px 8px}.side-title.secondary{margin-top:15px}.nav-link,.quick-link{display:block;text-decoration:none;color:#5c667e;padding:8px 9px;border-radius:9px;font-size:12px;margin:2px 0}.nav-link span{display:inline-block;width:23px;color:#9aa5bb;font-weight:900}.nav-link.active,.nav-link:hover,.quick-link:hover{background:var(--sky);color:var(--blue)}.quick-link{font-size:11px;padding:6px 9px}main{margin-left:210px}.scene{min-height:100vh;padding:112px max(7vw,70px) 56px;display:flex;align-items:center;position:relative;overflow:hidden;border-bottom:1px solid var(--line);scroll-snap-align:start}.scene-copy{max-width:650px}.chapter-kicker{display:inline-flex;align-items:center;gap:8px;color:var(--blue);background:var(--sky);padding:8px 12px;border-radius:99px;font-size:13px;font-weight:900}.chapter-kicker:before{content:"";width:7px;height:7px;background:currentColor;border-radius:50%}.chapter-number{font-size:72px;line-height:.9;color:#bfd0ff;font-weight:950}.scene h1,.scene 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#dce5f4;border-radius:10px;padding:11px 8px;font-size:12px;text-align:center}.test-flow p,.source-note{font-size:11px;color:#8994aa}.centered{display:block;text-align:center}.centered .chapter-kicker{margin-top:15px}.centered h2{max-width:800px;margin-left:auto;margin-right:auto}.cards{display:grid;gap:16px;margin:32px auto 14px;max-width:1050px;text-align:left}.cards3{grid-template-columns:repeat(3,1fr)}.card{padding:22px;border:1px solid var(--line);border-radius:20px;background:#fff;box-shadow:0 10px 32px rgba(30,45,80,.05)}.card span{color:var(--blue);font-size:12px;font-weight:900}.card b{display:block;font-size:21px;margin:9px 0}.card p{margin:0;color:var(--muted);font-size:14px}.card.purple span{color:var(--purple)}.card.orange span{color:#d66a25}.chapter-intro{justify-content:space-between;gap:30px;background:linear-gradient(140deg,#fff,#eaf1ff)}.chapter-route{display:flex;align-items:center;gap:12px}.chapter-route span{width:112px;padding:14px;background:#fff;border:1px solid #dce5f5;border-radius:14px}.chapter-route b{display:block}.chapter-route small{font-size:11px;color:var(--muted)}.chapter-route i{font-style:normal;color:var(--blue);font-size:22px}.route-map{display:flex;align-items:center;width:100%;gap:8px;margin-top:35px}.route-map div{flex:1;min-height:116px;padding:16px;border-radius:15px;background:#fff;border:1px solid var(--line)}.route-map b{display:block;font-size:16px}.route-map small{display:block;margin-top:8px;color:var(--muted);font-size:12px}.route-map i{font-style:normal;color:#99a6bd}.route-link{display:inline-block;margin-top:20px;color:var(--blue);font-weight:900;text-decoration:none}.dark{display:block;background:var(--navy);color:#fff}.dark .chapter-kicker{background:rgba(255,255,255,.1);color:#c2d6ff}.dark .lead{color:#c5d0e5}.loop-board{display:flex;align-items:center;gap:8px;margin-top:35px}.loop-board span{flex:1;padding:15px;background:rgba(255,255,255,.09);border:1px solid 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div:nth-of-type(6){border-color:#32ad87}.content-path b{font-size:15px}.content-path small{display:block;margin-top:18px;color:var(--muted);font-size:11px;line-height:1.5}.content-path i{display:grid;place-items:center;padding:0 4px;color:#9aa7bd;font-style:normal}.content-note{max-width:900px;margin:25px auto 0;padding:17px 21px;border-left:4px solid var(--orange);border-radius:9px 15px 15px 9px;background:#fff9ef;color:#5d6473;text-align:left}.milestone-line{display:grid;grid-template-columns:repeat(6,1fr);gap:10px;margin-top:35px}.milestone-line article{min-height:190px;padding:16px;border-radius:16px;background:#fff;border:1px solid var(--line);text-align:left}.milestone-line b{display:grid;place-items:center;width:26px;height:26px;color:#fff;background:var(--blue);border-radius:50%;font-size:11px}.milestone-line span{display:block;font-weight:900;margin:10px 0 7px}.milestone-line small{color:var(--muted);font-size:12px;line-height:1.5}.evidence-box{max-width:900px;margin:24px auto;padding:18px;border-radius:14px;background:#e8fbf5;border:1px solid #c2efe1;color:#176a56}.evidence-box b{display:block}.evidence-box span{font-size:13px}.value-scene{background:var(--navy);color:#fff;justify-content:space-between;gap:35px}.value-scene .chapter-kicker{background:rgba(255,255,255,.1);color:#a9c5ff}.value-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:10px;width:min(500px,46vw)}.value-grid a{text-decoration:none;color:#fff;padding:16px;border:1px solid rgba(255,255,255,.14);border-radius:13px;background:rgba(255,255,255,.05)}.value-grid b{display:block;color:#a7c5ff;font-size:12px}.value-grid span{display:block;font-weight:900;margin:5px 0}.value-grid small{font-size:11px;color:#c4cee0}.tour-caption{position:fixed;z-index:100;left:50%;bottom:25px;transform:translateX(-50%);width:min(730px,calc(100% - 42px));padding:16px 20px;background:rgba(16,28,53,.94);border:1px solid rgba(255,255,255,.15);box-shadow:var(--shadow);color:#fff;border-radius:14px;line-height:1.7}.tour-pointer{position:fixed;z-index:99;pointer-events:none;width:16px;height:16px;border-radius:50%;background:#ff7a45;box-shadow:0 0 0 7px rgba(255,122,69,.25)}.tour-pointer span{position:absolute;white-space:nowrap;top:-30px;left:-10px;background:#ff7a45;color:#fff;border-radius:7px;padding:3px 7px;font-size:11px;font-weight:800}@media(max-width:1000px){.sidebar{left:10px;width:170px}.scene{padding-left:42px;padding-right:42px}main{margin-left:180px}.product-tabs button{padding:8px;font-size:12px}.content-path{flex-wrap:wrap}.content-path div{flex-basis:28%}.content-path i{display:none}.milestone-line{grid-template-columns:repeat(3,1fr)}}@media(max-width:720px){html{scroll-snap-type:none}.topbar{padding:0 14px;gap:9px}.mobile-menu{display:block;border:0;background:transparent;font-size:22px}.product-tabs{display:none}.brand{font-size:14px}.tour-tools label{display:none}.sidebar{top:70px;left:0;transform:none;height:calc(100vh - 70px);border-radius:0;width:245px;translate:-105% 0;transition:.25s}.sidebar.open{translate:0}.scene{min-height:auto;padding:110px 22px 52px;display:block}main{margin:0}.hero-board,.compare-board,.teacher-board,.value-grid{width:100%;max-width:none;margin-top:28px}.split-scene{display:block}.cards3{grid-template-columns:1fr}.chapter-intro,.value-scene{display:block}.chapter-route{margin-top:26px;overflow:auto}.route-map,.loop-board{overflow:auto}.route-map div{min-width:125px}.loop-board span{min-width:120px}.content-path{display:grid;grid-template-columns:1fr 1fr}.content-path div{min-height:115px}.milestone-line{grid-template-columns:1fr 1fr}.scene h1{font-size:47px}.scene h2{font-size:37px}}