.mrt402-native,.mrt402-foundation{font:16px/1.7 system-ui,sans-serif;color:#283344}.mrt402-native img{max-width:100%;height:auto}.mrt402-native h2,.mrt402-foundation h2{font-size:1.4rem;margin:0 0 18px;color:#202c3c}.mrt402-native h3,.mrt402-foundation h3{font-size:1.08rem;margin:24px 0 8px}.mrt402-workspace{display:grid;grid-template-columns:210px minmax(0,1fr);background:#f5f7fb;border:1px solid #e4e8f0;border-radius:12px;overflow:hidden}.mrt402-tabs{display:flex;flex-direction:column;gap:2px;background:#fff;padding:16px 10px;border-right:1px solid #edf0f5;align-self:stretch}.mrt402-tabs button{font:inherit;text-align:left;padding:13px 16px;border:0;border-radius:8px;background:#fff;color:#475569;cursor:pointer}.mrt402-tabs button[aria-selected=true]{background:#e9f0ff;color:#3155b7;font-weight:650}.mrt402-panels{min-width:0;padding:24px}.mrt402-panels>[role=tabpanel],.mrt402-foundation{background:#fff;padding:26px;border:1px solid #e8ebf0;border-radius:12px;box-shadow:0 3px 14px #172c4c08}.mrt402-native details,.mrt402-foundation details{border:1px solid #e2e7ef;border-radius:8px;margin:12px 0;padding:12px}.mrt402-native summary,.mrt402-foundation summary{cursor:pointer;font-weight:650}.mrt402-native button,.mrt402-button{font:inherit;cursor:pointer}.mrt402-button{display:inline-block;border:0;border-radius:7px;padding:10px 16px;margin:8px 6px 8px 0;text-decoration:none!important;background:#3865df;color:white!important}.mrt402-prompt{padding:16px;background:#f0f4ff;border-radius:8px;border-left:3px solid #6382d8}.mrt402-hold{background:#fff0e8;border-left:4px solid #ac4224;padding:12px;color:#87351d}.mrt402-scope{font-size:13px;color:#68758a}.mrt402-native table{width:100%;border-collapse:collapse}.mrt402-native th,.mrt402-native td{text-align:left;padding:10px;border-bottom:1px solid #e4e9f0}.mrt402-code-image{overflow:auto;max-height:70vh;border:1px solid #dce3ed;padding:16px;background:#fff}.mrt402-code-image img{display:block;width:100%;max-width:none;height:auto}.mrt402-image-tools{display:flex;gap:10px;flex-wrap:wrap;margin:12px 0}.mrt402-image-tools button{border:1px solid #dce3ed;border-radius:6px;background:#fff;color:#344967;padding:6px 10px}.mrt402-native [hidden]{display:none!important}.mrt402-native :focus-visible{outline:3px solid #647de0;outline-offset:3px}@media(max-width:760px){.mrt402-workspace{grid-template-columns:1fr}.mrt402-tabs{flex-direction:row;flex-wrap:wrap;border-right:0;border-bottom:1px solid #e4e8f0;padding:8px}.mrt402-tabs button{padding:9px 12px}.mrt402-panels{padding:12px}.mrt402-panels>[role=tabpanel]{padding:18px}.mrt402-code-image{padding:5px}}
.mrt402-model-preview{margin:0 0 24px;background:#fafbfe;border:1px solid #e4e8f0;border-radius:12px;padding:16px}.mrt402-model-preview img{display:block;width:100%;height:330px!important;object-fit:contain}.mrt402-model-preview figcaption{font-size:12px;line-height:1.5;color:#64748b;margin-top:10px}.mrt402-activity-footer{display:flex;justify-content:space-between;align-items:center;gap:12px;margin-top:20px;padding-top:16px;border-top:1px solid #e5e9f1}.mrt402-activity-footer button{border:1px solid #dce3ef;border-radius:7px;background:#fff;color:#3757a1;padding:9px 13px}.mrt402-activity-footer button:disabled{opacity:.4;cursor:default}.mrt402-activity-footer span{font-size:12px;color:#64748b}.mrt402-native .mrt-assembly-viewer{margin:16px 0 26px}.mrt402-native .mrt-assembly-viewer .assembly-heading{padding:16px;gap:12px}.mrt402-native .mrt-assembly-viewer .assembly-heading h2{font-size:1.2rem!important}.mrt402-native .mrt-assembly-viewer .assembly-stage{height:50vh;min-height:300px}.mrt402-native .mrt-assembly-viewer .assembly-heading p{font-size:12px}.mrt402-native .mrt-assembly-viewer .assembly-tools{flex-wrap:wrap}.mrt402-native .mrt-assembly-viewer .assembly-drawing{max-width:none;height:auto}@media(max-width:760px){.mrt402-model-preview img{height:230px!important}.mrt402-activity-footer{gap:6px}.mrt402-activity-footer span{display:none}}
@media(min-width:1000px){.mrt402-model-preview{float:left;width:44%;margin:0 24px 18px 0;box-sizing:border-box}.mrt402-model-preview img{height:300px!important}#mrt402-intro>ul{clear:both}#mrt402-intro>h2{font-size:1.3rem}#mrt402-intro:after{content:"";display:block;clear:both}}
/* Focused student workspace — scoped to native 402 model pages. */
body.mrt402-lesson-mode{--mrt402-ink:#1e293b;--mrt402-muted:#617089;--mrt402-line:#e2e8f0;--mrt402-accent:#315dc6;--mrt402-soft:#eef3ff}
.mrt402-lesson-mode .mrt-451-page{max-width:1240px!important;padding:24px!important}
.mrt402-lesson-mode .mrt-451-page>h1{font-size:clamp(23px,2vw,30px)!important;letter-spacing:-.035em;margin-bottom:24px!important;color:var(--mrt402-ink)!important}
.mrt402-workspace{grid-template-columns:184px minmax(0,1fr);gap:24px;background:transparent;border:0;border-radius:0;overflow:visible;align-items:start}
.mrt402-tabs{position:sticky;top:48px;border:1px solid var(--mrt402-line);border-radius:12px;padding:8px;gap:4px;align-self:start;box-shadow:0 4px 18px #14294c04}
.mrt402-tabs button{display:flex;align-items:center;gap:12px;min-height:48px;padding:12px;font-size:14px;line-height:1.35;border-radius:8px;transition:background .15s,color .15s}
.mrt402-tabs button:before{content:attr(data-step-number);font-size:11px;font-weight:700;color:#8a97ab;letter-spacing:.02em}
.mrt402-tabs button:hover{background:#f6f8fc;color:var(--mrt402-accent)}
.mrt402-tabs button[aria-selected=true]{background:var(--mrt402-soft);color:var(--mrt402-accent)}
.mrt402-tabs button[aria-selected=true]:before{color:var(--mrt402-accent)}
.mrt402-panels{padding:0;scroll-margin-top:40px;min-width:0}
.mrt402-panels>[role=tabpanel]{padding:30px;border-radius:12px;box-shadow:0 6px 24px #20345505;border:1px solid var(--mrt402-line)}
.mrt402-panels>#mrt402-build{padding:0;background:transparent;border:0;box-shadow:none}
.mrt402-build-note{font-size:14px;line-height:1.65;color:#52647e;margin:0 0 16px;padding:12px 16px;background:#f4f7fc;border:1px solid #e5ebf5;border-radius:9px}
.mrt402-native .mrt-assembly-viewer{margin:0;border:1px solid #dce5eb;border-radius:12px;box-shadow:0 6px 24px #20345505;overflow:hidden}
.mrt402-native .mrt-assembly-viewer .assembly-heading{padding:14px 20px;background:#fff;border-bottom:1px solid #edf1f5;align-items:center}
.mrt402-native .mrt-assembly-viewer .assembly-heading small,.mrt402-native .mrt-assembly-viewer .assembly-heading p{display:none}
.mrt402-native .mrt-assembly-viewer .assembly-heading h2{font-size:16px!important;letter-spacing:-.01em;margin:0!important}
.mrt402-native .mrt-assembly-viewer .assembly-tools{gap:6px;flex-direction:row}
.mrt402-native .mrt-assembly-viewer .assembly-tools button{min-height:40px;min-width:40px;font-size:12px;border-radius:7px}
.mrt402-native .mrt-assembly-viewer .assembly-meta{padding:10px 20px;background:#fff}
.mrt402-native .mrt-assembly-viewer .assembly-stage{height:clamp(380px,56vh,660px);min-height:0;background:#fff}
.mrt402-native .mrt-assembly-viewer .assembly-note{padding:12px 20px;font-size:11px}
.mrt402-native .mrt-assembly-viewer .assembly-sequence{padding:14px 20px 6px;background:#fbfcfe}
.mrt402-native .mrt-assembly-viewer .assembly-sequence-heading{margin-bottom:10px}
.mrt402-native .mrt-assembly-viewer .assembly-thumbnail{border-radius:8px}
.mrt402-native .mrt-assembly-viewer .assembly-prev,.mrt402-native .mrt-assembly-viewer .assembly-next{width:44px;height:44px}
.mrt402-activity-footer{margin-top:16px;padding-top:16px;border-color:var(--mrt402-line)}
.mrt402-activity-footer button{min-height:44px;padding:10px 16px;font-size:14px;border-radius:8px;line-height:1.4}
.mrt402-activity-footer [data-next-activity]:not(:disabled){background:var(--mrt402-accent);border-color:var(--mrt402-accent);color:#fff;font-weight:600}
.mrt402-activity-footer button:hover:not(:disabled){filter:brightness(.96)}
.mrt402-activity-footer button:disabled{opacity:.45}
.mrt402-native details{background:#fbfcfe;border-color:#e2e8f0;border-radius:9px;padding:13px 15px}
.mrt402-native summary{font-size:14px;color:#405371}
.mrt402-native .mrt402-button{background:var(--mrt402-accent);border-radius:8px;font-size:14px;min-height:44px;box-sizing:border-box;padding:11px 16px}
.mrt402-code-start{margin:16px 0}
.mrt402-code-image{border-radius:10px;border-color:#e2e8f0}
.mrt402-lesson-completion{margin-top:28px!important;padding:22px!important;border:1px solid #d6e2f7!important;border-radius:10px!important;background:#f4f7ff!important}
.mrt402-lesson-completion button{min-height:44px;background:var(--mrt402-accent)!important;border-radius:8px!important;box-shadow:none!important}
.mrt402-lesson-completion input[type=checkbox]{width:18px;height:18px;vertical-align:middle;margin-right:8px}
.mrt402-lesson-mode .mrt-lesson-nav-bar{border-top:1px solid #e2e8f0;margin-top:30px;padding:20px 0 8px;gap:16px}
.mrt402-lesson-mode .mrt-lesson-nav-card,.mrt402-lesson-mode .mrt-lesson-nav-portal{background:#fff!important;border:1px solid #dfe6f0;border-radius:8px;box-shadow:none;padding:12px 16px}
.mrt402-lesson-mode .mrt-lesson-nav-title{color:#3d4d66!important;font-size:13px;white-space:normal}
.mrt402-lesson-mode .mrt-lesson-nav-label{color:#7c8ba1!important;font-size:10px}
.mrt402-lesson-mode .mrt-lesson-nav-icon{display:none}
.mrt402-lesson-mode .mrt-lesson-nav-portal{font-size:13px;min-height:44px;color:#425475}
.mrt402-lesson-mode #mrt-global-footer{display:none}
@media(max-width:900px){.mrt402-workspace{grid-template-columns:1fr;gap:16px}.mrt402-tabs{position:static;display:flex;flex-direction:row;flex-wrap:wrap;padding:6px;gap:4px}.mrt402-tabs button{flex:1 1 calc(33.333% - 4px);justify-content:center;gap:7px;padding:10px 7px;min-height:46px;font-size:13px}.mrt402-panels>[role=tabpanel]{padding:22px}.mrt402-model-preview{float:none;width:100%;margin:0 0 20px}.mrt402-panels{scroll-margin-top:16px}}
@media(max-width:600px){.mrt402-lesson-mode .mrt-451-page{padding:14px!important}.mrt402-panels>[role=tabpanel]{padding:18px}.mrt402-native .mrt-assembly-viewer .assembly-heading{padding:12px;flex-wrap:wrap;gap:10px}.mrt402-native .mrt-assembly-viewer .assembly-heading h2{font-size:15px!important}.mrt402-native .mrt-assembly-viewer .assembly-stage{height:48vh;min-height:280px}.mrt402-native .mrt-assembly-viewer .assembly-meta,.mrt402-native .mrt-assembly-viewer .assembly-sequence{padding-left:12px;padding-right:12px}.mrt402-native .mrt-assembly-viewer .assembly-note{display:none}.mrt402-native .mrt-assembly-viewer .assembly-tools button{min-height:40px;padding:7px 9px}.mrt402-activity-footer button{font-size:12px;padding:10px;max-width:48%}.mrt402-lesson-mode .mrt-lesson-nav-bar{display:grid;grid-template-columns:1fr 1fr;gap:10px}.mrt402-lesson-mode .mrt-lesson-nav-card{max-width:100%;padding:10px}.mrt402-lesson-mode .mrt-lesson-nav-center{grid-column:1/-1;grid-row:2}.mrt402-lesson-completion{padding:16px!important}}
@media(prefers-reduced-motion:reduce){.mrt402-tabs button{transition:none}}
/* Keep the model title in view when moving between activities. */
body.mrt402-lesson-mode #page .mrt-451-page{max-width:1240px!important;padding:24px!important}
.mrt402-panels{scroll-margin-top:112px}
.mrt402-native .mrt-assembly-viewer .assembly-note{display:none}
.mrt402-native .mrt-assembly-viewer .assembly-stage{height:clamp(380px,50vh,600px)}
@media(max-width:900px){.mrt402-panels{scroll-margin-top:24px}}
@media(max-width:600px){body.mrt402-lesson-mode #page .mrt-451-page{padding:14px!important}.mrt402-native .mrt-assembly-viewer .assembly-stage{height:48vh;min-height:280px}}