/* Concept-first reading: named ideas, grouped access, optional practice. */
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4rem);overflow-y:auto;overscroll-behavior:contain;padding-right:.65rem;scrollbar-width:thin;position:sticky;top:1.5rem}.concept-first .situation-index .index-group{margin:0 0 1rem}.concept-first .situation-index .index-group h3{font-size:.8rem;line-height:1.5;margin:1rem 0 .35rem;color:#486170}.concept-first .situation-index a{font-size:.85rem;line-height:1.4;padding:.65rem .2rem}.concept-first .situation-index a span{display:inline;font-size:.7rem;margin-right:.45rem}.concept-first .situation-index .selected-worksheet{font-size:.8rem}.concept-first .lesson-group-context{font-size:.85rem;line-height:1.5;color:#4a626f;margin:0}.concept-first .mobile-case-controls{margin-top:.5rem}.concept-first[data-case-enhanced="true"][data-show-all="false"] .learning-case:not(.selected-case){display:none}.concept-first[data-case-enhanced="true"] .mobile-case-controls{display:flex;gap:1rem;align-items:center;justify-content:space-between;background:transparent;border:0;padding:.5rem 0;margin-bottom:1rem}.concept-first .mobile-case-controls .mobile-lesson-choice{display:none}.concept-first .mobile-case-controls button{min-height:44px;padding:.6rem 1rem;font:inherit;font-size:.9rem;background:white;color:#193d50;border:1px solid #8fa7b2}.concept-first .selection-status{position:absolute;width:1px;height:1px;overflow:hidden;clip-path:inset(50%)}.concept-first .learning-tail{padding-bottom:1rem}.concept-first .source-note{font-size:.85rem;line-height:1.7;color:#52646b}.concept-first .lesson-disclosure summary:focus-visible,.concept-first .lesson-pager a:focus-visible{outline:3px solid #b68f2e;outline-offset:4px}.concept-first .diagram-support{display:grid;grid-template-columns:1fr 1fr;gap:.8rem}.concept-first .diagram-support>div{border:1px solid #adbec7;background:white;padding:.8rem;text-align:center;line-height:1.6}.concept-first .diagram-support .diagram-result,.concept-first .diagram-support .diagram-question{grid-column:1/-1}.concept-first .diagram-result{background:#eaf0f2!important;font-weight:650}.concept-first .diagram-question{border-style:dashed!important}.concept-first .support-direction{text-align:center;color:#567783;line-height:1}.concept-first .margin-equation{list-style:none;padding:0!important;margin:0}.concept-first .margin-equation li{display:flex;gap:1rem;align-items:center;padding:.7rem 0;border-bottom:1px solid #c5d1d7;line-height:1.6}.concept-first .math-sign{font-weight:700;color:#4a6d7c;min-width:1.1rem}.concept-first .margin-equation li:last-child{font-weight:700;border-top:2px solid #8da4ad;border-bottom:0}.mina-page .concept-first .lesson-example{background:#f5f5ef;border-color:#a9945a}.mina-page .concept-first .lesson-lead{line-height:1.95}
@media(max-width:999px){.concept-first .learning-layout{grid-template-columns:1fr}.concept-first .situation-index{position:static;max-height:20rem;display:block}.concept-first .situation-index .index-group{display:block}.concept-first .lesson-pager{gap:.7rem}}
@media(max-width:760px){.concept-first .learning-intro{margin-bottom:.5rem}.concept-first .learning-intro h1{font-size:1.8rem}.concept-first .learning-intro p{font-size:.95rem;line-height:1.75}.concept-first[data-case-enhanced="true"] .mobile-case-controls{display:grid;gap:.65rem;padding:1rem;border:1px solid #c4d2d8;background:#f2f6f7}.concept-first .mobile-case-controls .mobile-lesson-choice{display:block}.concept-first .mobile-lesson-choice label{display:block;font-weight:650;font-size:.9rem;margin-bottom:.55rem}.concept-first .mobile-lesson-choice select{width:100%;min-height:44px;padding:.55rem;font:inherit;font-size:1rem;background:white;color:#193d50;border:1px solid #8fa7b2}.concept-first .mobile-case-controls button{width:100%}.concept-first .lesson-hook{font-size:1.65rem}.concept-first .lesson-example,.concept-first .lesson-calculation,.concept-first .practice-box{padding:1rem}.concept-first .learning-case{padding-top:1rem}.concept-first .diagram-support{grid-template-columns:1fr}.concept-first .diagram-support .diagram-result,.concept-first .diagram-support .diagram-question{grid-column:auto}.concept-first .lesson-pager{display:block}.concept-first .lesson-pager a{display:block;text-align:left!important;margin-bottom:.5rem}}
@media print{.concept-first .learning-case{display:block!important}.concept-first .mobile-case-controls,.concept-first .situation-index,.concept-first .lesson-pager{display:none!important}.concept-first .learning-layout{display:block}.concept-first details,.concept-first details>*{display:block!important}.concept-first details::details-content{display:block!important;content-visibility:visible!important}.concept-first .lesson-hook{font-size:1.6rem}.concept-first .case-diagram{break-inside:avoid}}