@charset "UTF-8";
:root{font-family:"Segoe UI","Microsoft YaHei",sans-serif;color:#18303b;background:#f2f5f5;font-synthesis:none;--teal:#11796d;--border:#dce4e5;--muted:#697c85}*{box-sizing:border-box}body{margin:0}button,select{font:inherit}button{cursor:pointer;border:0;border-radius:7px;transition:background .15s,transform .15s}button:hover:not(:disabled){filter:brightness(.95)}button:active:not(:disabled){transform:translateY(1px)}button:disabled{cursor:not-allowed;opacity:.45}button:focus-visible,select:focus-visible,summary:focus-visible{outline:3px solid #45cbb6;outline-offset:3px}.topbar{height:72px;display:flex;align-items:center;gap:30px;padding:0 34px;background:white;border-bottom:1px solid var(--border)}.brand{display:flex;gap:11px;align-items:center;font-weight:700;font-size:18px;letter-spacing:.7px}.brand small{display:block;font-size:9px;letter-spacing:1.8px;color:var(--muted);margin-top:3px}.brand-icon{font-size:38px;color:var(--teal)}.course{border-left:1px solid var(--border);padding-left:28px;font-size:12px;color:#70828b}.topbar>.quiet{margin-left:auto}.quiet{background:transparent;color:#53707a;padding:10px 12px;font-size:12px}.key{font-size:11px;padding:2px 5px;border:1px solid currentColor;border-radius:4px;margin-left:9px;opacity:.65}main{padding:26px 34px 12px;max-width:1920px;margin:auto}.page-heading{display:flex;align-items:center;justify-content:space-between;margin-bottom:23px}.eyebrow{color:var(--teal);letter-spacing:1.5px;font-weight:600;font-size:11px;margin:0 0 8px}h1{font-size:28px;letter-spacing:.5px;margin:0 0 9px}h2{font-size:14px;margin:0}.subtitle{margin:0;color:var(--muted);font-size:12px}.capabilities{display:flex;align-items:center;gap:12px}.pill{font-size:11px;border:1px solid #cfdddd;border-radius:20px;padding:6px 11px;color:#657b83;background:#fafcfc}.pill.available{color:#11796d;background:#e4f4ef;border-color:#c8e7dc}.outline{border:1px solid #bfcfd1;background:white;color:#2b515c;padding:11px 17px;font-size:12px;font-weight:600}.workspace{display:grid;grid-template-columns:minmax(0,1fr) 310px;gap:20px;align-items:stretch}.scene-panel{background:white;border:1px solid var(--border);border-radius:12px;overflow:hidden;display:flex;flex-direction:column;min-width:0;box-shadow:0 5px 22px #18303b06}.scene-toolbar{height:49px;padding:0 18px;display:flex;gap:8px;align-items:center;border-bottom:1px solid #ffffff0b;background:#152832;color:#deeced}.scene-toolbar strong{font-size:12px;font-weight:500}.scene-toolbar>span:not(.live-dot){font-size:10px;color:#8da9b2;margin-left:5px}.live-dot{width:6px;height:6px;border-radius:50%;background:#65dec0;box-shadow:0 0 8px #65dec045}.camera-controls{margin-left:auto;display:flex;gap:3px}.camera-controls button{padding:5px 10px;font-size:10px;background:#263b46;color:#b8cbd1}.camera-controls button.active{background:#44776f;color:white}#viewport{min-height:450px;height:calc(100vh - 373px);max-height:720px;flex:1;position:relative;background:#12212c;overflow:hidden;touch-action:none}#viewport canvas{display:block;width:100%;height:100%;outline:none}.scene-label{position:absolute;top:20px;left:21px;font-size:9px;letter-spacing:2px;color:#6c919e;pointer-events:none}.scene-label span{color:#83c3b2;font-size:11px;margin-right:8px}.stage-note{position:absolute;top:21px;right:20px;font-size:11px;color:#9cbbc2;pointer-events:none;text-align:right}.stage-note span{display:block;font-size:9px;color:#5f8290;margin-top:7px}.scene-bottom{position:absolute;bottom:14px;left:0;right:0;display:flex;align-items:center;justify-content:center;gap:10px;font-size:10px;letter-spacing:.4px;color:#85a4b1;pointer-events:none}.scene-bottom i{font-style:normal;color:#45636e}.control-deck{padding:16px 18px 18px;border-top:1px solid var(--border)}.selected-info{display:flex;align-items:center;gap:12px;min-height:23px;margin-bottom:14px}.small-label{font-size:10px;color:#7a8d94;display:block}.selected-info strong{font-size:13px}.selected-info>span{font-size:10px;color:#6b838c;margin-left:auto}.selected-info .small-label{padding-right:10px;border-right:1px solid var(--border)}.adjustments{display:flex;align-items:end;gap:18px;flex-wrap:wrap}.adjust-group>.small-label{margin-bottom:6px}.button-row{display:flex;gap:4px;align-items:center}.button-row button:not(.primary):not(.outline){height:30px;min-width:32px;padding:0 8px;background:#edf2f3;color:#294f5a}.button-row select{border:1px solid #dce5e7;background:white;height:30px;border-radius:5px;font-size:11px;color:#51717c;max-width:61px}.primary{background:var(--teal);color:white;font-weight:600;font-size:12px;padding:12px 16px}.adjustments>.primary{margin-left:auto;height:36px;white-space:nowrap}.lesson-panel{background:white;border:1px solid var(--border);border-radius:12px;padding:19px 19px 10px;display:flex;flex-direction:column}.mode-switch{display:flex;background:#edf2f3;border-radius:7px;padding:3px}.mode-switch button{background:transparent;color:#75888e;font-size:12px;flex:1;padding:9px 6px}.mode-switch button.active{background:white;box-shadow:0 1px 4px #24454d14;color:var(--teal);font-weight:700}.mode-description{font-size:10px;line-height:1.75;margin:10px 0 15px;color:#83959b;min-height:35px}.stats{display:grid;grid-template-columns:1fr 1fr;background:#f5f8f8;border:1px solid #e8eeee;border-radius:9px;padding:13px 14px;margin-bottom:21px}.stats>div+div{border-left:1px solid #dce5e7;padding-left:16px}.stats span{display:block;font-size:10px;color:#8b9ba2;margin-bottom:6px}.stats strong{font-size:25px;font-weight:500;letter-spacing:1px;font-variant-numeric:tabular-nums}.stats strong small{font-size:10px;color:#98a8ae;letter-spacing:0}.progress-heading{display:flex;justify-content:space-between;align-items:center}.progress-heading h2{font-size:12px}.progress-heading>span{font-size:11px;color:var(--teal);font-weight:600}.progress-track{height:4px;border-radius:3px;background:#edf2f2;margin-top:10px;overflow:hidden}.progress-track div{height:100%;width:0;background:#2fab93;transition:width .3s}.parts-list{display:flex;flex-direction:column;gap:7px;margin:13px 0}.part-card{display:flex;align-items:center;gap:11px;padding:10px;background:white;border:1px solid #e5ebec;text-align:left;border-radius:7px}.part-card:hover:not(:disabled){background:#f6faf9}.part-card.selected{border-color:#56ad9a;background:#eff9f5;box-shadow:0 0 0 1px #56ad9a22}.part-card.done{background:#f5f9f8;border-color:#dceae5;opacity:1;cursor:default}.part-icon{height:32px;width:34px;display:grid;place-items:center;border-radius:6px;background:#edf2f4;color:#6c939c;font-size:22px;flex-shrink:0}.done .part-icon{color:#15957b;background:#ddf1e9;font-size:18px}.part-card.selected .part-icon{color:var(--teal);background:#dbefe7}.part-copy{flex:1}.part-copy strong{display:block;font-size:11px;font-weight:600;color:#2a4651}.part-copy small{display:block;font-size:9px;color:#8da0a6;margin-top:4px}.part-state{font-size:9px;color:#95a6aa}.done .part-state{color:#208d78}.selected .part-state{color:var(--teal)}.feedback{margin-top:2px;background:#eff5f7;border:1px solid #e1ebef;border-left:3px solid #7b9fad;border-radius:6px;padding:11px 12px;min-height:70px}.feedback strong{display:block;font-size:11px;margin-bottom:5px;color:#385865}.feedback span{font-size:10px;line-height:1.8;display:block;color:#738b95}.feedback.success{background:#edf8f1;border-color:#d9ece0;border-left-color:#30a276}.feedback.warning{background:#fff8ed;border-color:#f0e3cf;border-left-color:#d8a448}.feedback.warning strong{color:#856333}.error-line{display:flex;justify-content:space-between;gap:6px;font-size:9px;color:#9aabb0;margin:13px 0 15px}.error-line b{font-weight:600;color:#6a838d;margin-left:3px}.wide{width:100%;display:flex;justify-content:space-between;align-items:center}.secondary-actions{display:flex;justify-content:space-between;margin-top:3px}.secondary-actions .quiet{font-size:10px;padding:10px 5px}.history{border-top:1px solid #edf1f2;margin-top:auto;padding-top:10px}.history summary{font-size:10px;color:#7c9199;cursor:pointer;display:flex;justify-content:space-between}.history summary>span{color:#9faeb2}.history-item{display:flex;justify-content:space-between;font-size:9px;padding:9px 0;color:#82969e;border-bottom:1px solid #edf1f2}.history-item strong{color:#2c7166}footer{display:flex;justify-content:space-between;color:#9aaab0;font-size:9px;letter-spacing:.3px;padding:14px 2px 0}dialog{border:1px solid var(--border);border-radius:15px;box-shadow:0 24px 100px #091b3540;color:#25434e;padding:34px;width:min(760px,calc(100vw - 36px));max-height:90vh}dialog::backdrop{background:#102c426b;backdrop-filter:blur(4px)}dialog h2{font-size:24px;margin:8px 0 17px}dialog p{font-size:12px;line-height:1.85;color:#647f89}.close-dialog{position:absolute;top:13px;right:16px;background:transparent;font-size:24px;color:#6b858d;padding:4px 8px}.help-steps{display:grid;grid-template-columns:repeat(3,1fr);gap:12px;margin:22px 0}.help-steps>div{padding:16px;background:#f1f7f6;border:1px solid #e3eeeb;border-radius:8px}.help-steps b{display:block;color:#8fafaa;font-size:12px;margin-bottom:11px}.help-steps strong{font-size:14px}.help-steps p{font-size:11px;margin:8px 0 0}.muted{color:#9aaab0!important;font-size:10px!important}.result-score{display:flex;align-items:baseline;gap:9px;color:var(--teal);margin:23px 0 10px}.result-score span{font-size:74px;line-height:1;font-weight:600}.result-score small{font-size:16px}.result-details{background:#f2f7f6;padding:17px;border-radius:9px;margin:20px 0;font-size:12px;color:#66847d;line-height:2}.result-details strong{color:#2b665b}#resultDialog{width:480px}#sceneFallback{position:absolute;inset:30%;color:#cfddd9;font-size:13px;text-align:center;line-height:2;z-index:3}
@media(min-width:1500px){.workspace{grid-template-columns:minmax(0,1fr) 335px}.lesson-panel{padding:22px}.part-card{padding:12px}.parts-list{gap:9px}.mode-description{min-height:20px}.adjustments{gap:26px}.selected-info>span{font-size:11px}}
@media(max-width:1100px){main{padding:22px 18px}.topbar{padding:0 20px}.workspace{grid-template-columns:minmax(0,1fr) 275px;gap:14px}.lesson-panel{padding:15px 13px 10px}.adjustments{gap:11px}.adjustments>.primary{padding:10px 12px}.selected-info{flex-wrap:wrap;gap:7px}.selected-info>span{width:100%;margin:0}.selected-info{margin-bottom:9px}.scene-bottom{gap:6px}#viewport{min-height:420px}.course{display:none}.stage-note{display:none}.control-deck{padding:13px}.button-row button:not(.primary):not(.outline){min-width:29px}}
@media(max-width:800px){.topbar{height:64px}.brand{font-size:15px}.workspace{grid-template-columns:1fr}.page-heading{align-items:flex-start;gap:20px}.capabilities{flex-direction:column;gap:7px;align-items:flex-end}.capabilities .pill{font-size:9px}.subtitle{font-size:11px;line-height:1.6;max-width:300px}h1{font-size:23px}#viewport{height:470px;min-height:400px}.lesson-panel{padding:20px}.mode-description{min-height:0}.parts-list{display:grid;grid-template-columns:repeat(2,1fr)}.history{margin-top:10px}.help-steps{grid-template-columns:1fr}.scene-bottom{font-size:9px}.adjustments{gap:16px}.adjustments>.primary{margin-left:auto}footer{gap:20px;line-height:1.7}.selected-info>span{width:auto;margin-left:auto}.stats{margin-bottom:16px}.page-heading{margin-bottom:18px}.eyebrow{font-size:9px}}
/* Keep controls within a normal desktop screen; only a long task/history list scrolls. */
@media(min-width:801px){
  main{padding-top:20px}.page-heading{margin-bottom:19px}
  .workspace{height:calc(100vh - 226px);min-height:600px;max-height:830px}
  .scene-panel{height:100%}.scene-toolbar{flex:0 0 45px}
  #viewport{min-height:300px;height:auto;max-height:none;flex:1 1 auto}
  .control-deck{flex:0 0 auto;padding:14px 16px 15px}
  .lesson-panel{height:100%;padding:14px 15px 9px;overflow:hidden}
  .lesson-panel>*{flex-shrink:0}
  .mode-switch button{padding:8px 6px}
  .mode-description{min-height:0;margin:7px 0 10px}
  .stats{padding:10px 12px;margin-bottom:14px}.stats strong{font-size:24px}.stats span{margin-bottom:4px}
  .parts-list{flex:1 1 auto;min-height:106px;overflow-y:auto;gap:5px;margin:10px 0;scrollbar-width:thin;scrollbar-color:#c3d5d4 transparent;padding-right:2px}
  .part-card{flex-shrink:0;padding:7px 9px;gap:9px;min-height:43px}
  .part-icon{width:29px;height:28px;font-size:21px}.part-copy small{margin-top:2px}
  .feedback{min-height:62px;padding:9px 10px}.feedback span{line-height:1.7}
  .error-line{margin:10px 0 11px}
  .wide{padding:10px 14px}.secondary-actions .quiet{padding:8px 5px}
  .history{padding-top:8px;margin-top:0;max-height:90px;overflow-y:auto}
}
/* Assembly stages and training checks explain progress without submitting a part. */
.assembly-stages{display:flex;align-items:center;gap:12px;margin:0;padding:11px 18px;list-style:none;background:#f8fbfa;border-bottom:1px solid var(--border);flex:0 0 auto}.assembly-stages li{display:flex;align-items:center;gap:8px;color:#6a7c83;font-size:11px;flex:1}.assembly-stages li+li:before{content:'→';margin-right:5px;color:#899c9e}.assembly-stages li>span{width:21px;height:21px;display:grid;place-items:center;border:1px solid #c5d2d3;border-radius:50%;font-size:10px}.assembly-stages strong{font-weight:500}.assembly-stages small{margin-left:auto;font-size:10px}.assembly-stages .current{color:#0c6e61}.assembly-stages .current>span{background:#11796d;border-color:#11796d;color:white}.assembly-stages .complete>span{background:#d9eee6;color:#176a53;border-color:#bddbd0}.assembly-stages .complete strong{color:#176a53}.alignment-checks{display:flex;gap:15px;margin:-1px 0 11px;padding-bottom:9px;border-bottom:1px solid #e6eeeb;font-size:11px;color:#6d7d83}.alignment-checks[hidden]{display:none}.alignment-checks .ready{color:#11745d}
@media(max-width:1100px){.assembly-stages{padding:9px 13px;gap:6px}.assembly-stages li{gap:5px;font-size:10px}.assembly-stages li+li:before{margin-right:0}.assembly-stages small{font-size:9px}}
@media(max-width:500px){.assembly-stages li>span{display:none}.assembly-stages li{gap:4px}.assembly-stages{padding:10px;gap:5px}}

/* Public release: a visible first step, readable focus, and project context. */
.course,footer a{color:#476c65;text-decoration:none}.course:hover,footer a:hover{text-decoration:underline}
.first-steps{display:flex;align-items:center;gap:16px;background:#edf6f2;border:1px solid #cce0d6;border-radius:8px;padding:12px 16px;margin:0 0 16px;font-size:12px;line-height:1.8;color:#375c52}
.first-steps strong{white-space:nowrap;color:#176b59}.first-steps a{margin-left:auto;color:#176b59;white-space:nowrap;text-underline-offset:3px}
button:focus-visible,a:focus-visible,select:focus-visible,summary:focus-visible,canvas:focus-visible{outline:3px solid #209580;outline-offset:3px}
#clearHistoryBtn{font-size:11px;padding:8px 0}
@media(min-width:801px){.workspace{height:calc(100vh - 294px)}}
@media(max-width:800px){.first-steps{align-items:flex-start;flex-wrap:wrap;gap:6px 12px}.first-steps span{flex:1;min-width:200px}.first-steps a{margin-left:0}.scene-bottom{flex-wrap:wrap;padding:0 10px}footer{flex-wrap:wrap}}
@media(max-width:500px){
  .parts-list{grid-template-columns:1fr}.part-card{min-height:56px}.part-copy strong{font-size:12px}.part-copy small,.part-state{font-size:10px}
  .scene-toolbar{flex-wrap:wrap;height:auto;gap:7px;padding:10px}.scene-toolbar>strong{white-space:nowrap}.camera-controls{width:100%;margin-left:0;justify-content:space-between}.camera-controls button{white-space:nowrap;padding:7px 10px}
  .capabilities{min-width:85px}.capabilities .outline{white-space:nowrap}.scene-bottom{font-size:9px}#viewport{height:370px;min-height:370px;max-height:370px;flex:0 0 370px}
}