:root{--ink:#07132d;--muted:#66728a;--blue:#2d5bd8;--line:#dfe6f1;--soft:#f3f7fd;--mint:#e8faf4}*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:90px}body{margin:0;background:#fff;color:var(--ink);font-family:Inter,-apple-system,BlinkMacSystemFont,"PingFang SC","Microsoft YaHei",sans-serif;line-height:1.7}a{color:inherit;text-decoration:none}button,select,textarea{font:inherit}button{cursor:pointer}h1,h2,h3,h4,p{margin:0}button,a,select,textarea,summary{outline-offset:4px}button:focus-visible,a:focus-visible,select:focus-visible,textarea:focus-visible,summary:focus-visible{outline:3px solid #7398f0}.wrap{width:min(1180px,calc(100% - 48px));margin:auto}.header{position:sticky;top:0;z-index:5;background:rgba(255,255,255,.96);border-bottom:1px solid #edf1f7}.header-inner{height:72px;display:flex;align-items:center;justify-content:space-between;gap:20px}.brand{display:flex;align-items:center;gap:10px;font-weight:800;font-size:19px;line-height:1.2}.brand small{display:block;font-size:8px;letter-spacing:.13em;color:var(--muted);margin-top:5px}.brand-mark{border-radius:10px;background:#edf4ff;color:var(--blue);border:1px solid #cbdaf5;padding:8px;font-size:17px}nav{display:flex;gap:25px;font-size:13px;color:#53617b}nav a:hover,.small-link{color:var(--blue)}.hero{display:grid;grid-template-columns:1.15fr .85fr;align-items:center;gap:70px;padding-top:66px;padding-bottom:56px}.eyebrow{font-size:11px;font-weight:750;letter-spacing:.1em;color:var(--blue)}h1{font-size:clamp(38px,4.7vw,60px);line-height:1.17;letter-spacing:-.04em;margin:20px 0}h1 span{color:var(--blue)}.course-name{font-size:19px;font-weight:750;margin-bottom:12px}.intro{max-width:560px;color:var(--muted);font-size:15px}.actions{display:flex;flex-wrap:wrap;gap:12px;margin:25px 0 16px}.button{display:inline-flex;align-items:center;justify-content:center;gap:12px;min-height:43px;padding:10px 18px;border-radius:8px;border:1px solid #c6d5f0;font-size:13px;font-weight:650}.primary{background:var(--blue);color:#fff;border-color:var(--blue);box-shadow:0 6px 16px #2d5bd81c}.secondary{background:#fff;color:var(--blue)}.button:hover{filter:brightness(.97)}.button:disabled{opacity:.4;cursor:default}.availability{font-size:12px;color:var(--muted);display:flex;align-items:center;gap:7px}.dot{height:6px;width:6px;border-radius:50%;background:#279581}.outcome{border:1px solid #dbe5f3;border-radius:20px;padding:30px;background:linear-gradient(140deg,#f2f7ff,#fff 70%);box-shadow:0 16px 40px #294e8610}.outcome-row{display:flex;gap:20px;padding:22px 0;border-bottom:1px solid #e3eaf5;align-items:center}.outcome-row b{font-size:36px;font-weight:500;letter-spacing:-.06em;color:#5b80d7}.outcome-row strong{font-size:16px}.outcome-row p,.outcome-note{font-size:12px;color:var(--muted)}.outcome-note{padding-top:20px}.method{border-radius:16px;background:var(--soft);padding:26px 30px;display:grid;grid-template-columns:1fr 1.25fr;gap:30px;align-items:center}.method h2{font-size:23px;margin:5px 0}.method p{font-size:12px;color:var(--muted)}.method ol{list-style:none;padding:0;display:flex;justify-content:space-between;gap:10px;margin:0;font-size:12px}.method li{display:flex;flex-direction:column;gap:10px}.method b{font-size:11px;color:var(--blue);border:1px solid #d6e2f8;background:white;border-radius:50%;width:30px;height:30px;display:grid;place-items:center}.audience{padding-top:23px;color:var(--muted);font-size:13px}.audience p+p{margin-top:7px}.audience strong{color:#34435f}.section{padding-top:64px}.section-heading{display:flex;align-items:end;justify-content:space-between;gap:20px;margin-bottom:24px}.section-heading h2{font-size:28px;margin-top:5px;letter-spacing:-.04em}.section-heading>p{color:var(--muted);font-size:12px}.module-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:16px}.module-card{border:1px solid var(--line);border-radius:13px;overflow:hidden;background:#fff}.module-head{padding:19px 20px;background:#f4f7ff;border-bottom:1px solid var(--line)}.module-card:nth-child(2) .module-head,.module-card:nth-child(5) .module-head{background:#effaf6}.module-card:nth-child(3) .module-head,.module-card:nth-child(6) .module-head{background:#fff6e9}.module-head span{font-size:10px;color:var(--muted)}.module-head h3{font-size:16px;margin-top:4px}.module-lessons{padding:6px 14px}.course-link{display:flex;gap:10px;padding:15px 3px;border-bottom:1px solid #edf1f7}.course-link:last-child{border:0}.course-link:hover strong{color:var(--blue)}.course-link[aria-current="step"]{background:#f4f7ff;border-radius:5px}.course-link .num{font-size:11px;color:var(--blue);padding-top:3px}.course-link strong{display:block;font-size:13px;font-weight:600;line-height:1.6}.course-link small{display:block;color:var(--muted);font-size:10px;margin-top:5px}.workbench{display:grid;grid-template-columns:240px minmax(0,1fr);border:1px solid var(--line);border-radius:16px;overflow:hidden}.lesson-sidebar{padding:26px 20px;background:var(--soft);border-right:1px solid var(--line)}.lesson-sidebar label{font-size:12px;font-weight:700;display:block;margin-bottom:8px}select{width:100%;padding:10px 7px;border:1px solid #cdd9eb;border-radius:7px;background:#fff;color:var(--ink);font-size:12px}#lessonContext{font-size:12px;color:var(--muted);margin:22px 0}#lessonContext strong{display:block;color:var(--ink);margin-bottom:8px}.small-link{font-size:12px}.lesson-body{padding:32px;min-width:0}.lesson-top{display:flex;justify-content:space-between;gap:12px}.status{background:#fff3e1;color:#896024;border-radius:5px;font-size:10px;padding:3px 7px}h3#lessonTitle{font-size:26px;line-height:1.4;margin:14px 0 9px;letter-spacing:-.025em}.muted{color:var(--muted);font-size:12px}.video-note{display:flex;gap:14px;padding:17px 20px;background:#f5f7fb;border:1px dashed #d5dfee;border-radius:9px;margin:23px 0}.video-note>span{font-size:25px;color:#8294b5}.video-note strong{font-size:13px}.video-note p{font-size:12px;color:var(--muted);margin-top:4px}.lesson-facts{display:grid;grid-template-columns:1fr 1fr;gap:12px}.fact{padding:18px;border:1px solid #e1e8f3;border-radius:9px}.fact h4{font-size:12px;color:var(--blue);margin-bottom:9px}.fact p{font-size:13px;color:#4e5f7b;line-height:1.85}.fact.output{background:#effaf6;border-color:#d8eee4}.fact.output h4{color:#207966}.feynman{margin:22px 0;padding:18px;border-left:3px solid #7694db;background:#f4f7ff;border-radius:0 8px 8px 0}.feynman strong{font-size:12px;color:var(--blue)}.feynman p{font-size:14px;margin-top:7px}.prompt-head{display:flex;align-items:center;justify-content:space-between;gap:10px}h4{font-size:16px}.text-button{border:0;border-radius:5px;background:#edf3ff;color:var(--blue);font-size:12px;padding:7px 10px}.hint{font-size:11px;color:var(--muted);margin:8px 0 12px}pre{white-space:pre-wrap;overflow-wrap:anywhere;font:13px/1.9 inherit;font-family:inherit;font-size:13px;line-height:1.9;background:#f7f9fc;border:1px solid var(--line);padding:18px;border-radius:9px;margin:12px 0 20px}details{border-top:1px solid var(--line);padding:14px 0}summary{cursor:pointer;font-size:13px;font-weight:650;color:#40577f}.example{padding:18px;background:#f8faff;border-radius:8px;margin-top:13px;font-size:13px;color:#52617a}.example p+p{margin-top:12px}.example ol{padding-left:18px}.example li{margin:10px 0}.worksheet{margin-top:20px;border-top:1px solid var(--line);padding-top:24px}.worksheet label{display:block;font-size:12px;font-weight:650;margin:16px 0 7px}textarea{display:block;resize:vertical;width:100%;min-height:90px;padding:12px;border:1px solid #ccd8eb;border-radius:8px;color:var(--ink);background:#fff;font-size:13px;line-height:1.8}.worksheet-actions{display:flex;align-items:center;gap:15px;flex-wrap:wrap;margin:15px 0 23px}#saveState{font-size:11px;color:var(--muted)}.lesson-nav{display:flex;justify-content:space-between;gap:10px;border-top:1px solid var(--line);padding-top:22px;margin-top:15px}.references{max-width:850px;padding-bottom:50px}.references h2{font-size:23px;margin-bottom:15px}.references p{font-size:13px;line-height:1.9;color:var(--muted);margin-bottom:12px}.footer{border-top:1px solid var(--line);padding-top:22px;padding-bottom:30px;display:flex;justify-content:space-between;gap:16px;font-size:11px;color:var(--muted)}.notice{position:fixed;bottom:25px;left:50%;transform:translateX(-50%);padding:12px 20px;background:#122749;color:white;font-size:13px;border-radius:10px;z-index:10;max-width:90vw}.notice[hidden],details[hidden]{display:none}
@media(max-width:900px){.hero{gap:30px;grid-template-columns:1fr 1fr}.module-grid{grid-template-columns:1fr 1fr}.method{grid-template-columns:1fr}.workbench{grid-template-columns:190px minmax(0,1fr)}.lesson-body{padding:24px}.lesson-facts{grid-template-columns:1fr}}
@media(max-width:600px){.wrap{width:calc(100% - 32px)}.header-inner{height:64px;gap:10px}nav{gap:12px;font-size:11px}nav a:first-child{display:none}.brand{font-size:16px}.hero{grid-template-columns:1fr;padding-top:36px;gap:28px;padding-bottom:30px}h1{font-size:42px}.course-name{font-size:17px}.intro{font-size:14px}.outcome{padding:22px}.outcome-row{padding:15px 0}.outcome-row b{font-size:30px}.method{padding:22px;gap:20px}.method ol{gap:6px;font-size:10px}.method h2{font-size:22px}.section{padding-top:40px}.section-heading{display:block}.section-heading h2{font-size:25px}.section-heading>p{margin-top:10px}.module-grid{grid-template-columns:1fr}.workbench{grid-template-columns:1fr}.lesson-sidebar{border-right:0;border-bottom:1px solid var(--line);padding:18px}#lessonContext{margin:12px 0}.lesson-body{padding:20px 16px}h3#lessonTitle{font-size:23px}.prompt-head h4{font-size:14px}.footer{flex-wrap:wrap}.video-note{padding:14px}.lesson-facts{gap:10px}}@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}}
/* Course mind map: bounded, keyboard-scrollable large-image viewer. */
.mindmap-panel{border:1px solid var(--line);border-radius:12px;overflow:hidden;background:#f7f9fc}.map-tools{display:flex;align-items:center;flex-wrap:wrap;gap:8px;padding:13px;background:#fff;border-bottom:1px solid var(--line)}.map-tools .button{min-height:38px;padding:7px 12px}.map-tools output{min-width:44px;text-align:center;font-size:12px;color:#53617b}.map-tools label{font-size:12px;margin-left:6px}.map-tools select{width:auto;max-width:200px;min-height:38px}.map-viewport{height:600px;max-height:70vh;overflow:auto;overscroll-behavior:contain;cursor:grab;touch-action:pan-x pan-y;position:relative}.map-viewport.dragging{cursor:grabbing}.map-viewport img{display:block;max-width:none;height:auto;user-select:none}.map-caption{font-size:11px;color:var(--muted);padding:10px 15px;background:#fff}.map-downloads{display:flex;flex-wrap:wrap;gap:15px;margin-top:13px}.mindmap-panel:fullscreen{display:flex;flex-direction:column;background:#f7f9fc;border:0;border-radius:0}.mindmap-panel:fullscreen .map-viewport{flex:1;height:auto;max-height:none}.map-tools .button:disabled{opacity:.4}.map-viewport:focus-visible{outline:3px solid #7398f0;outline-offset:-3px}@media(max-width:600px){.map-tools{gap:6px;padding:10px}.map-tools .button{font-size:11px;min-height:40px}.map-tools select{flex:1;max-width:none;min-width:130px}.map-viewport{height:460px;max-height:65vh}.map-downloads{gap:12px}.header nav{gap:10px}}

.brand-logo{display:block;position:relative;width:128px;height:48px;overflow:hidden;flex:none}.brand-logo img{position:absolute;width:184px;height:auto;max-width:none;left:-28px;top:-13px}