:root{font-family:Inter,'Noto Sans CJK SC','Microsoft YaHei',sans-serif;color:#203d38;background:#eff3eb;font-size:14px}*{box-sizing:border-box}body{margin:0;height:100dvh;overflow:hidden}button,select{font:inherit;color:inherit}button,a,select{touch-action:manipulation}button{cursor:pointer;border:1px solid #b5c9bf;border-radius:9px;background:#fff;padding:9px 13px;min-height:42px}button:hover{background:#e4eee6}button:focus-visible,a:focus-visible,select:focus-visible{outline:3px solid #3a8dc3;outline-offset:2px}button[aria-selected=true],button[aria-pressed=true]{background:#175f53;color:#fff}header{height:74px;display:flex;align-items:center;gap:20px;padding:12px 24px;border-bottom:1px solid #c8d6cd;background:#fafcf7}header a{color:#276d5e;text-decoration:none;white-space:nowrap}header div{flex:1}header b{font-size:20px;display:block}header span{font-size:12px;color:#698075;display:block;margin-top:4px}main{height:calc(100dvh - 74px);display:grid;grid-template-columns:minmax(300px,35%) minmax(0,1fr);gap:14px;padding:14px}#questionPanel,#modelPanel{background:#fff;border:1px solid #cddbd2;border-radius:15px;min-height:0;overflow:hidden;display:flex;flex-direction:column}#questionPanel{padding:16px 20px}.question-toolbar{display:flex;justify-content:space-between;font-size:12px;color:#608070}h1{font-size:20px;margin:12px 0}.question-tabs{display:flex;gap:8px;padding-bottom:12px;border-bottom:1px solid #e0e7df}.question-tabs button{flex:1}#questionContent{flex:1;min-height:0;overflow:auto;padding:6px 4px 12px;line-height:1.85;font-size:15px}#questionContent p{margin:10px 0}.eq{font-family:'STIX Two Math','Times New Roman',serif;white-space:normal;padding:0 3px;font-size:1.08em}.source-figure{display:block;text-align:center;margin:12px 0}.source-figure img{max-width:100%;max-height:220px;object-fit:contain}#questionPanel footer{display:flex;gap:8px;padding-top:12px;border-top:1px solid #e0e7df;justify-content:space-between}#markDone{font-size:12px}.answer-lead{font-size:18px;font-weight:700;color:#216858}.source-note{font-size:12px;color:#6c7e75}#modelPanel{padding:12px 16px 7px}.model-heading{display:flex;gap:8px;align-items:center}.model-heading div{flex:1}.model-heading b{font-size:17px}.model-heading span{display:block;font-size:11px;color:#678275;margin-top:3px}.model-heading select{max-width:170px;min-height:38px;border:1px solid #bdcfc3;border-radius:8px;background:#f7faf5}#modelScene{flex:1;min-height:180px;margin-top:7px;background:#f6f9f3;border-radius:12px;overflow:hidden}#modelScene svg{display:block;width:100%;height:100%;user-select:none}#modelScene .drag-handle{cursor:grab;touch-action:none}#modelScene .drag-handle:active{cursor:grabbing}#modelStatus{font-size:12px;min-height:30px;padding:6px 1px;color:#287553}#modelStatus.invalid{color:#b94432}#modelReadings{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:5px 12px;border-top:1px solid #dbe7dc;padding-top:8px;min-height:58px}#modelReadings div{font-size:11px;color:#668071}#modelReadings b{display:block;color:#233f38;font-size:17px;font-weight:600}#modelPresets{display:flex;gap:7px;padding:9px 0}#modelPresets button{min-height:35px;font-size:12px;padding:6px 10px}#modelParameters{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:8px 18px}#modelParameters label{font-size:11px;color:#4b6b5d}#modelParameters .param-title{display:flex;align-items:center;justify-content:space-between;gap:5px}#modelParameters input[type=number]{width:70px;min-height:29px;border:1px solid #b5c9bf;border-radius:5px;padding:3px 5px;background:#fafcf7;font-size:12px;color:#214c41}#modelParameters input[type=range]{width:100%;margin:3px 0;accent-color:#217c6a;cursor:pointer;height:20px}.model-caption{font-size:10px;color:#708478;margin:5px 0 0}aside{position:fixed;z-index:5;top:74px;bottom:0;left:0;width:310px;background:#f8fbf5;box-shadow:10px 0 40px #163f3828;border-right:1px solid #b4cbbd;padding:20px;overflow:auto}aside.closed{display:none}aside h2{margin:0 0 10px;font-size:20px}aside p,aside small{color:#718375;font-size:12px;line-height:1.7}aside nav h3{font-size:13px;color:#3f705a;margin:20px 0 8px}aside nav button{display:block;width:100%;text-align:left;font-size:12px;margin:5px 0;min-height:38px}aside nav button.active{background:#175f53;color:white}dialog{border:1px solid #bbd0c0;border-radius:16px;max-width:850px;width:90vw;max-height:85dvh;padding:20px;color:#20463b}dialog::backdrop{background:#163d3655}.dialog-head{display:flex;justify-content:space-between;align-items:center;position:sticky;top:0;background:#fff}.dialog-head h2{font-size:20px}#answerTable{overflow:auto;max-height:60dvh}table{border-collapse:collapse;width:100%;font-size:13px}th,td{text-align:left;border-bottom:1px solid #dae5da;padding:10px;vertical-align:top}td button{font-size:12px;min-height:32px}#printAnswers{margin-top:15px}@media(min-width:1600px){main{grid-template-columns:minmax(350px,32%) 1fr}#questionContent{font-size:17px}}@media(max-width:900px){header{gap:9px;padding:10px 12px}header b{font-size:16px}header span{font-size:10px}header button{font-size:12px;padding:6px 8px}main{grid-template-columns:38% 1fr;padding:8px;gap:8px}#questionPanel{padding:12px}#modelPanel{padding:10px}#modelParameters{grid-template-columns:repeat(2,minmax(0,1fr));gap:4px 12px}#modelReadings{gap:4px;min-height:50px}#modelReadings b{font-size:15px}.model-heading select{max-width:100px;font-size:11px}.model-caption{font-size:9px}#modelPresets{gap:4px}#modelPresets button{font-size:10px;padding:5px}#questionPanel footer{gap:4px}#questionPanel footer button{font-size:10px;padding:5px}h1{font-size:17px}#questionContent{font-size:13px}}@media(max-width:620px){body{overflow:auto;height:auto}header{height:68px;flex-wrap:wrap;gap:6px}header a{font-size:11px}header div{min-width:150px}header span{display:none}header button{min-height:32px;font-size:10px}main{height:calc(100dvh - 68px);display:flex;flex-direction:column;gap:6px}#questionPanel{height:37%;flex:none;padding:8px 12px}#questionPanel h1{margin:5px 0;font-size:15px}.question-tabs{padding-bottom:4px}.question-tabs button{min-height:28px;padding:3px}#questionContent{padding-top:0;font-size:12px;line-height:1.6}#questionPanel footer{padding-top:4px}#questionPanel footer button{min-height:26px}#modelPanel{flex:1;padding:7px 10px}#modelScene{min-height:100px}.model-heading b{font-size:13px}.model-heading span{display:none}#modelStatus{min-height:20px;padding:3px;font-size:10px}#modelReadings{min-height:34px;grid-template-columns:repeat(3,1fr);padding-top:3px}#modelReadings div{font-size:9px}#modelReadings b{font-size:12px}#modelPresets{padding:3px 0}#modelPresets button{min-height:26px}#modelParameters{grid-template-columns:repeat(3,minmax(0,1fr));gap:2px 6px}#modelParameters label{font-size:9px}#modelParameters .param-title{display:block}#modelParameters input[type=number]{min-height:22px;width:100%;font-size:10px;padding:1px 4px}#modelParameters input[type=range]{height:14px;margin:1px 0}.model-caption{font-size:8px;margin-top:2px}.source-figure img{max-height:120px}aside{top:68px}.model-heading select{min-height:26px}header #answersToggle{display:none}}@media print{body{overflow:visible;height:auto}header,main,.dialog-head button,#printAnswers{display:none}dialog#answerOverview{display:block;position:static;width:100%;max-width:none;max-height:none;border:0}#answerTable{overflow:visible;max-height:none}td button{border:0;padding:0}tr{break-inside:avoid}.dialog-head{position:static}}

#lectureResponse{display:flex;flex-wrap:wrap;align-items:center;gap:6px;padding:8px 0;font-size:12px}#lectureResponse:empty{display:none}#lectureResponse button{min-height:32px;padding:5px 9px}#lectureResponse small{font-size:11px;color:#517a62}.print-solution{display:none}@media print{.print-solution{display:block;line-height:1.8}}@media(max-width:620px){#lectureResponse{gap:4px;padding:3px 0;font-size:10px}#lectureResponse button{min-height:23px;padding:2px 7px;font-size:10px}}

#knowledgeContent{line-height:1.85;overflow:auto;max-height:65dvh;padding:5px 12px}#knowledgeContent p{margin:10px 0}#knowledgeContent img{max-width:100%;max-height:200px}

#constructionControls{display:flex;flex-wrap:wrap;gap:5px;align-items:center;padding:7px 0 2px;flex:none}#constructionControls select,#criticalScenario{font:inherit;font-size:11px;padding:5px 7px;min-height:31px;border:1px solid #bdcfc3;border-radius:7px;background:#fafcf7;color:#2c5c48;max-width:145px}#constructionControls label{display:flex;gap:3px;align-items:center;font-size:11px}#constructionStep{min-height:31px;padding:5px 8px;font-size:11px}#constructionStep:disabled{opacity:.45;cursor:default}#modelPresets{overflow-x:auto;flex:none;align-items:center}#modelPresets>*{flex:none}#criticalScenario{max-width:220px}#modelStatus{max-height:44px;overflow:auto;line-height:1.4;min-height:31px}.model-heading span{white-space:nowrap;overflow:hidden;text-overflow:ellipsis;max-width:480px}.model-heading div{min-width:0}#modelScene{min-height:170px}#specialPreset{display:none}
@media(max-width:900px){#constructionControls{gap:3px;padding:5px 0 0}#constructionControls select{max-width:110px;font-size:10px;padding:3px;min-height:28px}#constructionStep{font-size:10px;padding:3px;min-height:28px}.model-heading span{max-width:300px;font-size:9px}#modelStatus{font-size:10px;max-height:33px;min-height:28px}#modelReadings{min-height:45px}}
@media(max-width:620px){#constructionControls{flex-wrap:nowrap;overflow-x:auto}#constructionControls select{max-width:91px;font-size:9px;min-height:24px}#constructionControls label{font-size:9px}#constructionStep{font-size:9px;min-height:24px;white-space:nowrap}#modelScene{min-height:100px}#modelStatus{min-height:20px;max-height:25px;font-size:9px}#modelReadings{min-height:30px}#criticalScenario{min-height:24px;font-size:10px;max-width:165px}}

@media(min-width:901px){#constructionControls select,#constructionStep{font-size:12px;min-height:35px}#constructionControls select{max-width:170px}#composeFirst,#composeSecond{max-width:145px}}