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@media(max-width:850px){.bc-main{width:min(100% - 38px,760px)}.bc-hero{grid-template-columns:minmax(0,1fr) 260px;gap:22px;padding:38px 32px}.bc-method-section{grid-template-columns:1fr}.bc-lab-card{grid-template-columns:1fr 1fr}}
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@media print{.topbar,.bc-hero,.bc-branch-switch,.bc-map-section,.bc-method-section,.bc-lessons-section,.bc-lab-section,.bc-review-section,.bc-bottom,.footer,.bc-heading>.bc-print{display:none!important}.bc-formula-section{margin:0}.bc-formula-grid{grid-template-columns:repeat(2,1fr)}.bc-formula-card{break-inside:avoid}.bc-formula-section .bc-heading h2{font-size:22px}}
@media(prefers-reduced-motion:reduce){.branch-course-page *{scroll-behavior:auto!important;transition:none!important}}

@media(max-width:650px){.branch-course-page .topnav{display:none}}


/* Explicit, child-friendly lesson explanations */
.bc-lesson-key-preview{display:block;margin-top:5px;color:#567c5e!important;font-size:10px!important;line-height:1.55;font-weight:700!important;white-space:normal;max-width:760px}
.bc-map-text small strong{color:#4d7656}
.bc-deep-guide{margin:14px 0;padding:17px;border:1px solid #d9e7d5;border-radius:16px;background:linear-gradient(135deg,#f0f7ed,#fffefa 75%);box-shadow:inset 3px 0 #80a983}
.bc-topic-visual{display:grid;gap:8px;margin:14px 0 0;padding:12px;border:1px solid #e4ebdf;border-radius:12px;background:#fffefa}.bc-topic-visual-art{min-width:0;overflow:hidden}.bc-topic-visual svg{display:block;width:min(100%,520px);height:auto;margin:0 auto}.bc-topic-visual figcaption{display:grid;gap:4px;color:#617166;font-size:10px;line-height:1.7}.bc-topic-visual figcaption b{color:#405d48;font-size:11px}
.bc-deep-head{display:flex;align-items:center;justify-content:space-between;gap:10px;margin-bottom:12px}
.bc-deep-head span{color:#355f43;font-size:14px;font-weight:900}
.bc-deep-head small{padding:5px 9px;border-radius:99px;background:#e3efdf;color:#54765a;font-size:9px;font-weight:900}
.bc-deep-idea{padding:13px 14px;border:1px solid #e2ebdd;border-radius:12px;background:#fffefa}
.bc-deep-idea>b{display:block;margin-bottom:5px;color:#648363;font-size:10px;font-weight:900;letter-spacing:.04em}
.bc-deep-idea p{margin:0;color:#394c3f;font-size:13px;line-height:1.9;font-weight:600}
.bc-subtopics{margin-top:15px}
.bc-subtopics>h4,.bc-flow-wrap>h4{margin:0 0 9px;color:#435b49;font-size:12px}
.bc-subtopic-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:8px}
.bc-subtopic{display:flex;align-items:flex-start;gap:8px;min-height:83px;padding:11px;border:1px solid #e6ebe1;border-radius:11px;background:#fffefa}
.bc-subtopic>span{display:grid;flex:0 0 24px;width:24px;height:24px;place-items:center;border-radius:8px;background:#edf3e9;color:#527a58;font-size:9px;font-weight:900}
.bc-subtopic b{display:block;color:#425849;font-size:11px;line-height:1.5}
.bc-subtopic p{margin:4px 0 0;color:#68776c;font-size:10px;line-height:1.75}
.bc-flow-wrap{margin-top:15px}
.bc-deep-flow{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:8px;align-items:stretch}
.bc-flow-node{position:relative;display:flex;align-items:center;gap:8px;min-height:42px;padding:8px 11px;border:1px solid #dce8d8;border-radius:10px;background:#f8fbf5;color:#496b50}
.bc-flow-node:not(:last-child):after{position:absolute;right:-9px;z-index:1;width:10px;background:#f0f7ed;color:#86a586;text-align:center;content:"→";font-size:12px;font-weight:900}
.bc-flow-node i{display:grid;flex:0 0 21px;width:21px;height:21px;place-items:center;border-radius:7px;background:#e5efe1;color:#54805c;font-size:9px;font-style:normal;font-weight:900}
.bc-flow-node b{font-size:10px;line-height:1.5}
.bc-worked-steps{display:grid;gap:7px;margin:10px 0 0;padding:0;list-style:none}
.bc-worked-steps li{display:flex;align-items:flex-start;gap:9px;padding:9px 10px;border:1px solid #e9ede5;border-radius:10px;background:#fffefa}
.bc-worked-steps li>i{display:grid;flex:0 0 22px;width:22px;height:22px;place-items:center;border-radius:7px;background:#eaf2e7;color:#4b7753;font-size:9px;font-style:normal;font-weight:900}
.bc-worked-steps b{display:block;color:#45634b;font-size:10px;line-height:1.55}
.bc-worked-steps p{margin:3px 0 0;color:#5f6f63;font-size:11px;line-height:1.8}
.bc-why-check{display:grid;grid-template-columns:1fr 1fr;gap:8px;margin:10px 0;padding:10px 12px;border:1px solid #e5eadd;border-radius:11px;background:#f8f9f3}
.bc-why-check p{margin:0;color:#647266;font-size:10px;line-height:1.75}
.bc-why-check b{display:block;margin-bottom:3px;color:#58745b;font-size:10px}
@media(max-width:650px){
  .bc-lesson-key-preview{font-size:9px!important;max-width:100%}
  .bc-deep-guide{padding:13px}
  .bc-deep-head span{font-size:13px}
  .bc-deep-idea p{font-size:12px;line-height:1.85}
  .bc-subtopic-grid{grid-template-columns:1fr}
  .bc-subtopic{min-height:0;padding:10px}
  .bc-subtopic p,.bc-worked-steps p{font-size:11px}
  .bc-deep-flow{grid-template-columns:1fr;gap:5px}
  .bc-flow-node{min-height:35px}
  .bc-flow-node:not(:last-child):after{right:auto;bottom:-10px;left:50%;width:16px;content:"↓"}
  .bc-why-check{grid-template-columns:1fr}
}

/* Readable body text for the newly expanded teaching blocks */
.bc-deep-idea p{font-size:14px}
.bc-subtopic b{font-size:12px}
.bc-subtopic p{font-size:11px}
.bc-flow-node b{font-size:11px}
.bc-worked-steps p{font-size:12px}
.bc-why-check p{font-size:11px}
@media(max-width:650px){.bc-deep-idea p{font-size:12.5px}.bc-subtopic p,.bc-why-check p{font-size:11.5px}.bc-worked-steps p{font-size:12px}}


/* Geometry lesson diagrams and the hands-on 3D solid explorer */
.bc-geometry-figure{display:grid;grid-template-columns:minmax(0,1fr);justify-items:center;gap:7px;margin:10px 0 14px;padding:12px 14px 10px;border:1px solid #e5ebdf;border-radius:14px;background:linear-gradient(135deg,#fbfcf8,#f2f7ef)}
.bc-geometry-figure svg{display:block;width:min(100%,540px);height:auto;max-height:230px;overflow:visible}
.bc-geometry-figure figcaption{max-width:720px;margin:0;color:#5e7063;font-size:10px;line-height:1.75;text-align:center}
.bc-solid-controls{display:grid;align-content:start;gap:13px;min-width:0}
.bc-solid-controls>p{margin:0;color:#68766d;font-size:10px;line-height:1.85}
.bc-solid-controls .bc-control-row{display:grid;grid-template-columns:37px minmax(60px,1fr) 35px;gap:10px}
.bc-solid-controls .bc-control-row input[type=range]{width:100%}
.bc-solid-controls .bc-control-row output{color:#3d7655;font-size:12px;font-weight:900;text-align:right}
.bc-solid-actions{display:flex;flex-wrap:wrap;gap:7px}
.bc-solid-actions .bc-lab-button{min-height:34px;padding:0 10px}
.bc-solid-visual{min-width:0;overflow:hidden}
#bc-solid-canvas{display:block;width:100%;height:260px;touch-action:none;cursor:grab;outline:none}
#bc-solid-canvas:focus-visible{border-radius:10px;box-shadow:0 0 0 3px #c7dfc6}
#bc-solid-canvas.is-dragging{cursor:grabbing}
.bc-solid-legend{display:flex;justify-content:center;flex-wrap:wrap;gap:14px;color:#65736a;font-size:10px}
.bc-solid-legend span{display:flex;align-items:center;gap:5px}
.bc-solid-legend i{display:inline-block;width:9px;height:9px;border-radius:3px;background:#bd794c}
.bc-solid-legend .bc-legend-width{background:#6585a0}
.bc-solid-legend .bc-legend-height{background:#507a59}
.bc-solid-legend b{color:#365d43}
@media(max-width:650px){.bc-geometry-figure{padding:9px 7px}.bc-geometry-figure figcaption{font-size:9px}.bc-solid-controls .bc-control-row{grid-template-columns:32px minmax(50px,1fr) 28px;gap:7px}#bc-solid-canvas{height:220px}.bc-solid-actions{gap:5px}.bc-solid-actions .bc-lab-button{padding:0 8px;font-size:9px}}
@media(prefers-reduced-motion:reduce){#bc-solid-canvas{scroll-behavior:auto}}

.bc-geometry-promise{display:flex;flex-wrap:wrap;gap:8px;margin:12px 0 0;color:#4b7256;font-size:10px;font-weight:900}
.bc-geometry-promise span{padding:6px 10px;border:1px solid #dfe9d9;border-radius:999px;background:#f2f7ee}
@media(max-width:650px){.bc-geometry-promise{font-size:9px;gap:6px}}


/* Formula-first learning: keep equations visually separate from explanatory prose. */
.bc-lesson-formula{margin:11px 0 14px;padding:14px 16px;border:2px solid #c9dfc6;border-radius:15px;background:linear-gradient(135deg,#edf6e9,#fffefa 82%);box-shadow:inset 4px 0 #5c9468}
.bc-formula-label{display:block;color:#477150;font-size:10px;font-weight:900;letter-spacing:.06em}
.bc-lesson-formula code{display:block;margin-top:6px;color:#253f30;font-family:"Nunito","Noto Sans SC",sans-serif;font-size:clamp(16px,2vw,22px);font-weight:900;line-height:1.75;white-space:normal;overflow-wrap:anywhere;word-break:normal;font-variant-numeric:lining-nums tabular-nums}
.bc-formula-support{color:#53645a;font-size:11px;line-height:1.8}
.bc-rich-line{display:block;min-width:0;white-space:normal;overflow-wrap:anywhere;word-break:normal}
.bc-rich-prose{margin:0}
.bc-rich-math{width:fit-content;max-width:100%;margin:5px 0;padding:6px 10px;border-radius:9px;background:#edf4e9;color:#2e523b;font-family:"Nunito","Noto Sans SC",sans-serif;font-size:clamp(14px,1.7vw,18px);font-weight:850;line-height:1.7;font-variant-numeric:lining-nums tabular-nums}
.bc-concept-text{color:#526159;font-size:11px;line-height:1.9}
.bc-concept-text .bc-rich-math{font-size:clamp(15px,1.8vw,19px)}
.bc-question-copy{display:block;flex:1;min-width:0}
.bc-question-copy .bc-rich-math{font-size:14px}
.bc-question-level{color:#57714f;font-size:.82em;font-weight:900}
.bc-example-solution{display:grid;gap:3px;margin:8px 0 0;padding:9px 10px;border-left:3px solid #78a47b;border-radius:0 9px 9px 0;background:#f1f6ed;color:#53645a;font-size:11px;line-height:1.8}
.bc-example-solution>b{color:#426e50}
.bc-formula-card code{font-size:16px;line-height:1.8;overflow-wrap:anywhere;word-break:normal;font-variant-numeric:lining-nums tabular-nums}
.bc-formula-card .bc-formula-support{font-size:11px}
.bc-formula-card .bc-rich-math{font-size:15px}
@media(max-width:650px){
  .bc-lesson-formula{padding:12px}
  .bc-lesson-formula code{font-size:16px;line-height:1.7}
  .bc-rich-math{font-size:15px;padding:7px 8px}
  .bc-concept-text .bc-rich-math{font-size:15px}
  .bc-formula-card code{font-size:16px}
}

/* Individual equation rows: one relationship per visual line. */
.bc-formula-lines{display:grid;gap:6px;margin:8px 0 2px}
.bc-formula-lines .bc-rich-math{width:auto;margin:0;padding:7px 10px;background:#e8f2e5;color:#294c36;font-size:clamp(17px,2vw,22px);font-weight:900;line-height:1.65}
.bc-formula-lines .bc-rich-prose{padding:4px 2px;color:#365542;font-size:clamp(14px,1.6vw,18px);font-weight:850;line-height:1.7}
.bc-formula-card .bc-formula-lines{gap:4px;margin:7px 0}
.bc-formula-card .bc-formula-lines .bc-rich-math{padding:5px 8px;font-size:15px;line-height:1.7}
.bc-formula-card .bc-formula-lines .bc-rich-prose{font-size:14px}
@media(max-width:650px){.bc-formula-lines .bc-rich-math{font-size:17px;padding:7px 8px}.bc-formula-card .bc-formula-lines .bc-rich-math{font-size:16px}}

.bc-live-result .bc-rich-math{display:block;width:fit-content;max-width:100%;margin:.3em 0;padding:.28em .55em;border-radius:8px;background:#f7fbf4;color:#31573c;font-size:clamp(1rem,1.8vw,1.2rem);font-weight:900;line-height:1.75;overflow-wrap:anywhere}
.bc-live-result .bc-rich-prose,.bc-lab-foot .bc-rich-prose{display:block;line-height:1.75}
.bc-lab-foot .bc-rich-math{display:block;width:fit-content;max-width:100%;margin:.3em 0;padding:.25em .5em;border-radius:7px;background:#fffefa;color:#3d6148;font-size:1rem;font-weight:900;line-height:1.7;overflow-wrap:anywhere}
.bc-path-answer{margin:0 0 .35em;color:#31573c;font-size:clamp(15px,1.7vw,19px);font-weight:900;line-height:1.65}.bc-path-rule{margin:0;color:#617166;font-size:12px;line-height:1.7}
@media(max-width:650px){.bc-live-result .bc-rich-math,.bc-lab-foot .bc-rich-math{font-size:1.02rem;line-height:1.8}}

.bc-method-choice{margin:11px 0;padding:11px 13px;border:1px solid #dfe8d9;border-left:3px solid #6f9a72;border-radius:10px;background:#f2f7ee;color:#58695d;font-size:10px;line-height:1.8}.bc-method-choice>b{display:block;margin-bottom:3px;color:#456d50;font-size:10px}.bc-method-choice p{margin:0}
.bc-topic-table-wrap{max-width:100%;margin:12px 0;padding:11px;border:1px solid #e1e8dc;border-radius:12px;background:#fffefa;overflow-x:auto;-webkit-overflow-scrolling:touch}.bc-topic-table{width:100%;border-collapse:collapse;color:#536258;font-size:10px;line-height:1.65;text-align:left}.bc-topic-table caption{padding:0 0 8px;color:#466f50;font-size:10px;font-weight:900;text-align:left}.bc-topic-table th,.bc-topic-table td{min-width:68px;padding:7px 9px;border:1px solid #e6ebe2;vertical-align:top}.bc-topic-table th{background:#f3f6ee;color:#4e7051;font-weight:900}.bc-topic-table tbody th[scope="row"]{white-space:nowrap}
@media(max-width:560px){.bc-topic-table-wrap{padding:8px}.bc-topic-table{font-size:9px}.bc-topic-table th,.bc-topic-table td{min-width:56px;padding:6px 5px}.bc-method-choice{font-size:10px}}

.bc-transfer{margin:11px 0;padding:11px 13px;border:1px solid #dfe8dc;border-left:3px solid #87a98b;border-radius:10px;background:#f3f7ef}
.bc-transfer>b{display:block;margin:0 0 4px;color:#426d4e;font-size:10px}
.bc-transfer>p{margin:0;color:#56665b;font-size:11px;line-height:1.8;overflow-wrap:anywhere}
@media(max-width:650px){.bc-transfer{padding:11px}.bc-transfer>p{font-size:12px}}

.bc-counting-path-box li{font-size:11px;line-height:1.65}
@media(max-width:650px){.bc-counting-path-box li{font-size:12px}}


/* Applicability and mathematical boundary examples */
.bc-boundary-guide{margin:12px 0;padding:14px;border:1px solid #e4e9df;border-radius:14px;background:#f8faf5}
.bc-boundary-heading{display:flex;align-items:baseline;justify-content:space-between;gap:10px;margin-bottom:9px}
.bc-boundary-heading h4{margin:0;color:#3d5745;font-size:12px;line-height:1.6}
.bc-boundary-heading>span{color:#778579;font-size:9px;line-height:1.5}
.bc-boundary-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:9px}
.bc-boundary-case{min-width:0;padding:11px 12px;border:1px solid #e5e9e1;border-radius:11px;background:#fffefa;overflow-wrap:anywhere}
.bc-boundary-case.is-applicable{border-color:#d9e8d5;background:#fcfefb}
.bc-boundary-case.is-boundary{border-color:#eee2d4;background:#fffdf9}
.bc-boundary-tag{display:inline-block;margin-bottom:5px;padding:3px 7px;border-radius:99px;background:#edf4e9;color:#4c7655;font-size:9px;font-weight:900}
.bc-boundary-case.is-boundary .bc-boundary-tag{background:#f7efe3;color:#8c704b}
.bc-boundary-case h4{margin:0 0 7px;color:#34483a;font-size:10px;line-height:1.7}
.bc-boundary-case p{margin:5px 0 0;color:#66736a;font-size:10px;line-height:1.8;overflow-wrap:anywhere}
.bc-boundary-case p b{color:#4e6f54}
@media(max-width:650px){.bc-boundary-guide{padding:11px}.bc-boundary-heading{align-items:flex-start;flex-direction:column;gap:2px}.bc-boundary-grid{grid-template-columns:1fr}.bc-boundary-case{padding:10px}.bc-boundary-case h4{font-size:11px}.bc-boundary-case p{font-size:10px}}