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30px);overflow:auto}.rail h2{font-size:17px;margin:0 0 8px}.rail p{font-size:12px;color:#55708c}.track{height:7px;background:#e8eff8;border-radius:99px;overflow:hidden}.track span{display:block;height:100%;width:0;background:#3982d7}.nav-list{display:grid;gap:5px;margin-top:12px}.nav-list button{width:100%;display:flex;gap:9px;align-items:center;justify-content:space-between;text-align:left;color:#3e5c7d;background:#f7fafe;border:1px solid #e3ecf8;border-radius:7px;padding:9px;font-size:12px}.nav-list button.active{background:#e5efff;border-color:#5b92db;color:#20559e;font-weight:900}.nav-list button.done{background:#eff9f2;color:#166947}.nav-list button b{display:inline-flex;width:43px;flex:none}.lesson{min-width:0;padding:24px}.lesson h2{font-size:25px;margin:6px 0;color:#1d416b;letter-spacing:-.045em}.lead{background:#f1f6fe;border-left:4px solid #2f72c6;padding:12px 14px;color:#355a83}.meta{font-size:12px;color:#6582a2}.block{border:1px solid #e0e8f1;border-radius:10px;padding:15px;margin:15px 0;min-width:0}.block h3{font-size:16px;margin:0 0 10px}.op-head{display:flex;justify-content:space-between;flex-wrap:wrap;gap:10px;align-items:center}.op-head span{font-weight:850}.action-note{font-size:12px;color:#2767b1;font-weight:800;margin:8px 0}.marker{background:#edf3fa;color:#24588e;padding:8px 10px;border-radius:6px;overflow-wrap:anywhere;white-space:pre-wrap}.code-tools{display:flex;justify-content:flex-end;background:#1c3855;border-radius:8px 8px 0 0;padding:8px}.copy{font-weight:800;font-size:11px;background:#d9eafb;color:#19528f;border:0;padding:6px 12px;border-radius:5px}pre{margin:0;color:#eaf5ff;background:#14283e;padding:13px;border-radius:0 0 8px 8px;white-space:pre;overflow-x:auto;max-height:380px;font:12px/1.6 Consolas,monospace;tab-size:2}.shot-grid{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,.7fr);gap:14px}.shot-grid img{display:block;width:100%;height:auto;max-height:370px;object-fit:contain;object-position:top;background:#edf2f8;border:1px solid #d9e2ee;border-radius:6px}.shot-grid figure{min-width:0;margin:0}.shot-grid figcaption{font-weight:700;margin:8px 0;font-size:12px}.notes ul{padding-left:20px;color:#49627f}.notes li{margin:7px 0}.checklist label{display:block;padding:9px 6px;border-bottom:1px solid #e9eef6;font-size:13px}.checklist input{accent-color:#2773c7;margin-right:8px}.controls{display:flex;justify-content:space-between;gap:10px;margin-top:20px}.controls button{border:1px solid #b7ceed;border-radius:7px;padding:9px 16px;color:#245da6;background:#edf4ff;font-weight:800}.controls button:disabled{opacity:.4;cursor:not-allowed}.warn{padding:10px 12px;background:#fff5e9;color:#94632d;border-radius:6px;font-size:12px}.foot{font-size:11px;color:#71859f;padding:22px;text-align:center}@media(max-width:950px){.layout{grid-template-columns:1fr}.rail{position:static;max-height:none}.nav-list{grid-template-columns:repeat(4,minmax(0,1fr))}.nav-list button{flex-direction:column;align-items:flex-start;font-size:10px;gap:0}.lesson{padding:16px}}@media(max-width:530px){.top{flex-direction:column;align-items:flex-start;gap:5px}.hero{margin:12px auto}.nav-list{grid-template-columns:repeat(4,minmax(0,1fr))}.nav-list button{padding:6px;overflow:hidden}.shot-grid{grid-template-columns:1fr}.shot-grid img{max-height:320px}.hero-actions .button{flex:1 1 auto}.lesson h2{font-size:22px}pre{font-size:11px}.op-head{flex-direction:column;align-items:flex-start}}
/* R44: learning package, not answer snapshots */
.student-packet-note{padding:13px 15px;border-left:4px solid #26856b;background:#eaf8f1;color:#245647;border-radius:7px;max-width:960px;font-size:13px}.student-packet-note strong{font-weight:900}