.lesson-list.rich{gap:12px}.lesson-card{border:1px solid rgba(255,255,255,.08);background:#0a1728;border-radius:16px;overflow:hidden}.lesson-card-head{display:grid;grid-template-columns:auto 46px 1fr auto auto;gap:10px;align-items:center;padding:13px 14px}.lesson-card-head input{width:18px;height:18px;accent-color:#64d5ff}.lesson-card.done{opacity:.78}.lesson-card.done .lesson-card-title{text-decoration:line-through}.lesson-card-title{font-weight:760}.lesson-open{border:1px solid #35506d;background:#11263f;color:#eaf5ff;border-radius:10px;padding:8px 10px;cursor:pointer}.lesson-open:hover{border-color:#64d5ff}.lesson-expanded{border-top:1px solid rgba(255,255,255,.07);padding:18px;background:linear-gradient(180deg,#0d1e32,#0a1728)}.lesson-expanded-grid{display:grid;grid-template-columns:1.35fr .65fr;gap:14px}.learn-card{padding:17px;border:1px solid rgba(255,255,255,.07);border-radius:15px;background:#0b1a2c}.learn-card h3{margin:4px 0 10px}.learn-card p,.learn-card li{color:#d2deeb;line-height:1.65}.learn-card ul,.learn-card ol{padding-left:20px}.objective-list{display:grid;gap:7px}.objective-list li::marker{color:#64d5ff}.exam-tip{border-left:3px solid #ffc96b}.key-term-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:8px}.key-term{padding:10px;border-radius:11px;background:#081522;border:1px solid rgba(255,255,255,.06)}.key-term strong{display:block;color:#e8f6ff;margin-bottom:3px}.key-term span{font-size:.83rem;color:#aebed1;line-height:1.45}.lesson-check{margin-top:10px;padding:12px;border-radius:12px;background:#101f35}.lesson-check summary{cursor:pointer;font-weight:760;color:#bcecff}.lesson-check p{margin-bottom:0}
.textbook-shell{display:grid;grid-template-columns:minmax(0,1fr) 300px;gap:16px}.textbook-main{display:grid;gap:14px}.textbook-chapter{padding:25px}.textbook-chapter h2{margin:6px 0 12px;font-size:1.55rem}.textbook-chapter p{color:#d6e2ee;line-height:1.78;font-size:1rem}.textbook-sidebar{display:grid;gap:12px;align-content:start}.sticky-study-card{position:sticky;top:150px}.equation-chip{display:inline-block;margin:4px 6px 4px 0;padding:6px 9px;border-radius:9px;background:#102845;border:1px solid #29496c;color:#cdeeff;font-family:ui-monospace,SFMono-Regular,Menlo,monospace}.worked-example{border-top:3px solid #64d5ff}.worked-example ol{padding-left:22px}.worked-example li{margin:8px 0;color:#d7e5f1}.diagram-card{overflow:hidden}.science-diagram{display:grid;place-items:center;min-height:250px;padding:12px;background:radial-gradient(circle at 50% 50%,rgba(100,213,255,.09),transparent 55%),#071422;border-radius:14px;margin-top:12px}.science-diagram svg{width:min(100%,620px);height:auto;max-height:300px}.science-diagram text{font-family:Inter,system-ui,sans-serif;fill:#dcefff;font-size:13px}.science-diagram .line{stroke:#79d7ff;stroke-width:3;fill:none}.science-diagram .soft{fill:#17304b;stroke:#5a8db7;stroke-width:2}.science-diagram .accent{fill:#64d5ff}.science-diagram .warm{fill:#ffc96b}.science-diagram .bio{fill:#52d39a}.science-diagram .chem{fill:#c995ff}.science-diagram .physics{fill:#62b9ff}
.activity-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:14px}.activity-card{padding:21px}.activity-card h3{margin:7px 0 10px}.activity-card p{color:#d2deeb;line-height:1.65}.activity-steps{display:grid;gap:8px;margin-top:14px}.activity-step{display:flex;gap:10px;align-items:flex-start;padding:10px;border-radius:11px;background:#091728}.activity-step span{width:25px;height:25px;display:grid;place-items:center;border-radius:50%;background:#153b5d;color:#cdefff;font-weight:850;flex:none}.activity-step p{margin:2px 0 0;font-size:.87rem}.challenge-card{border-top:3px solid #ffc96b}.practical-method{display:grid;grid-template-columns:repeat(2,1fr);gap:10px;margin-top:12px}.practical-method div{padding:13px;border-radius:12px;background:#091728}.practical-method strong{display:block;margin-bottom:5px}.practical-method span{color:#aebed1;font-size:.84rem;line-height:1.5}
.simulator{padding:23px}.sim-layout{display:grid;grid-template-columns:320px 1fr;gap:18px;align-items:stretch}.sim-controls{display:grid;gap:12px}.sim-control{display:grid;gap:6px}.sim-control label{display:flex;justify-content:space-between;gap:12px;color:#cbd8e5;font-size:.82rem}.sim-control input[type=range]{width:100%;accent-color:#64d5ff}.sim-stage{min-height:310px;border:1px solid rgba(255,255,255,.07);border-radius:16px;background:radial-gradient(circle at 50% 50%,rgba(100,213,255,.08),transparent 55%),#071421;display:flex;flex-direction:column;align-items:center;justify-content:center;padding:22px;text-align:center;position:relative;overflow:hidden}.sim-result{font-size:clamp(2rem,5vw,4rem);font-weight:900;letter-spacing:-.04em}.sim-unit{color:#aebed1}.sim-caption{max-width:560px;color:#b5c5d7;line-height:1.55}.sim-visual{width:90%;height:110px;margin:15px 0;position:relative}.sim-bar{position:absolute;left:0;bottom:0;height:100%;width:12px;border-radius:99px;background:#64d5ff;box-shadow:28px 0 0 rgba(100,213,255,.75),56px 0 0 rgba(100,213,255,.5),84px 0 0 rgba(100,213,255,.3)}.sim-wave{position:absolute;inset:0;background:repeating-radial-gradient(ellipse at left center,transparent 0 18px,rgba(100,213,255,.55) 19px 21px,transparent 22px 36px)}.sim-note{padding:10px 12px;border-radius:11px;background:#17263b;color:#b7c8da;font-size:.8rem;line-height:1.45}.sim-equation{font-family:ui-monospace,SFMono-Regular,Menlo,monospace;color:#bfeeff;margin-bottom:12px}
.exam-toolbar{display:flex;justify-content:space-between;gap:15px;align-items:end;margin-bottom:16px}.exam-list{display:grid;gap:14px}.exam-card{padding:21px}.exam-card-head{display:flex;justify-content:space-between;gap:12px;align-items:flex-start}.mark-badge{min-width:65px;text-align:center;border:1px solid #365371;border-radius:99px;padding:5px 8px;color:#bcd0e5;font-size:.74rem}.exam-card textarea{width:100%;min-height:120px;resize:vertical;border:1px solid #29405c;background:#071421;color:#f4f7fb;border-radius:12px;padding:12px;margin:14px 0;outline:none}.exam-card textarea:focus{border-color:#64d5ff}.mark-result{margin-top:12px;padding:13px;border-radius:12px;background:#0e2530;border:1px solid #245364}.mark-result strong{display:block;margin-bottom:5px}.mark-result p{margin:5px 0;color:#c5d5e4;line-height:1.5}.mark-points{display:flex;gap:6px;flex-wrap:wrap;margin-top:8px}.mark-point{font-size:.75rem;padding:5px 7px;border-radius:8px;background:#17263a;color:#aebed1}.mark-point.hit{background:#12362c;color:#baf4d9}.exam-warning{font-size:.78rem;color:#aab9ca;line-height:1.5;max-width:760px}.question-actions{display:flex;gap:8px;justify-content:flex-end}.model-answer{margin-top:10px;padding:12px;border-radius:12px;background:#102a25;border:1px solid #245744;color:#c9f8e5;line-height:1.55}
@media(max-width:900px){.lesson-expanded-grid,.textbook-shell,.sim-layout{grid-template-columns:1fr}.textbook-sidebar{grid-row:1}.sticky-study-card{position:static}.activity-grid{grid-template-columns:1fr}.lesson-card-head{grid-template-columns:auto 38px 1fr auto}.lesson-card-head .badge{grid-column:3}.practical-method{grid-template-columns:1fr}}
@media(max-width:640px){.lesson-card-head{grid-template-columns:auto 32px 1fr}.lesson-open{grid-column:3;width:100%}.key-term-grid{grid-template-columns:1fr}.exam-toolbar{display:grid}.question-actions{justify-content:stretch}.question-actions .button{flex:1}.simulator,.textbook-chapter,.activity-card,.exam-card{padding:17px}.science-diagram{min-height:210px}}