.math-shelf{max-width:1150px}.math-hero{margin-bottom:24px}.math-topics{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:18px}.math-topic{text-align:left;color:inherit;cursor:pointer;padding:25px;width:100%;min-height:165px}.math-topic h2{margin:12px 0;font-size:23px}.math-topic small,.math-source-note{color:#6d657c}.math-topic span{color:#6250af;font-weight:650}.math-tabs{display:flex;gap:8px;overflow-x:auto;padding:5px 1px 16px}.math-tabs button{white-space:nowrap;flex-shrink:0;min-height:44px}.math-filter{display:flex;justify-content:space-between;gap:20px;align-items:end;padding:20px}.math-filter label,.math-output label{display:grid;gap:7px;font-weight:600}.math-filter form{display:flex;gap:8px;align-items:end}.math-filter input,.math-filter select,.math-output select,.math-output input:not([type=checkbox]){box-sizing:border-box;max-width:100%;font:inherit;padding:11px;border:1px solid #d5cde4;border-radius:10px;background:white;color:#332a49}.math-filter input{width:155px}.math-source-note{font-size:14px;line-height:1.65}.math-toolbar{display:flex;align-items:start;justify-content:space-between;gap:12px;margin:24px 0}.math-output{max-width:400px}.math-output>summary{cursor:pointer;min-height:44px;padding:10px 16px;border-radius:12px;background:#eee9fa;color:#554292;font-weight:650}.math-output>div{padding:16px;border:1px solid #ddd5ed;border-radius:12px;display:grid;gap:12px;background:white}.math-output label:has([type=checkbox]){display:flex;align-items:center;gap:10px}.math-output small{line-height:1.5}.math-question-list{display:grid;gap:20px}.math-question{padding:24px;margin:0;min-width:0}.math-question-meta,.math-question-footer{display:flex;align-items:center;justify-content:space-between;gap:14px;font-size:13px;color:#6e637f;flex-wrap:wrap}.math-question-meta>span{font-weight:700;letter-spacing:.03em;color:#67519c}.math-question label{display:flex;gap:7px;align-items:center;min-height:36px}.math-question input[type=checkbox],.math-output input[type=checkbox]{width:19px;height:19px;accent-color:#6651b8}.math-prompt{font-size:18px;line-height:1.75;margin:18px 0;overflow-wrap:anywhere}.math-help{border-top:1px solid #e5dfed;border-bottom:1px solid #e5dfed;margin:16px 0}.math-help>summary{display:flex;justify-content:space-between;align-items:center;list-style:none;cursor:pointer;font-weight:700;color:#5b459d;padding:16px 0;min-height:48px}.math-help>summary::-webkit-details-marker{display:none}.math-help[open]>summary span{transform:rotate(45deg)}.math-worked{border-left:4px solid #6aa687;background:#f0f8f3;border-radius:10px;padding:10px 20px;margin-bottom:18px;line-height:1.8;overflow-wrap:anywhere}.math-worked h3{font-size:16px;color:#386c52}.math-source{max-width:100%;overflow-wrap:anywhere}.math-source summary{cursor:pointer;padding:10px}.math-documents{display:grid}.math-documents>a{display:grid;gap:7px;padding:18px 0;border-bottom:1px solid #e7e0ee;text-decoration:none}.math-documents small{color:#71637f}.math-shelf button:focus-visible,.math-shelf summary:focus-visible,.math-shelf a:focus-visible{outline:3px solid #8974cf;outline-offset:3px}.math-shelf [hidden]{display:none!important}@media(max-width:650px){.math-topics{grid-template-columns:1fr}.math-topic{min-height:140px;padding:20px}.math-filter{display:grid;gap:16px}.math-filter form{flex-wrap:wrap}.math-filter label,.math-filter select{width:100%}.math-filter form label{flex:1}.math-filter input{width:100%}.math-toolbar{display:grid}.math-output{width:100%;max-width:none}.math-question{padding:18px}.math-prompt{font-size:17px}.math-worked{padding:8px 14px}.math-question-meta{display:grid}.math-question-footer{align-items:start}.math-shelf .hero h1{font-size:29px}.math-shelf{overflow-wrap:anywhere}}
/* Clearly signposted navigation and compact practice prompts. */
.math-study .math-study-crumbs{display:flex;align-items:center;flex-wrap:wrap;gap:8px}
.math-study .math-study-crumbs button{min-height:42px;border:1px solid #d9c9f3;border-radius:11px;padding:9px 13px;background:#f0e9ff;color:#51358e;font-weight:750;text-decoration:none;cursor:pointer}
.math-study .math-study-crumbs .math-study-chapters-button{background:#7150ba;border-color:#7150ba;color:#fff}
.math-study .math-study-crumbs .math-study-home-button{background:white;color:#5b5270}
.math-study .math-study-crumbs button:hover{filter:brightness(.96)}
.math-study .math-study-empty{background:transparent;border:0;border-left:3px solid #d5c6ec;border-radius:0;padding:4px 10px;margin:12px 0;font-size:13px;color:#71647d}
.math-document-view{max-width:980px}
.math-study-document-back{border:0;background:transparent;color:#6043a5;font-weight:750;padding:10px 0;margin-bottom:12px;cursor:pointer}
.math-document-frame{background:#f5f2fa;border:1px solid #e2d9ef;border-radius:16px;overflow:hidden}
.math-document-frame iframe{display:block;border:0;width:100%;height:min(75vh,900px);min-height:420px;background:white}
.math-document-actions{display:flex;justify-content:flex-end;flex-wrap:wrap;gap:10px;padding:18px 0}
.math-document-actions a,.math-document-actions button{min-height:44px;display:inline-flex;align-items:center;justify-content:center;text-decoration:none;padding:11px 17px;border-radius:11px;font-weight:700}
.math-document-private{font-size:12px;color:#746a80;margin:0 0 20px}
@media(max-width:650px){.math-document-frame iframe{height:65vh;min-height:340px}.math-document-actions>*{flex:1 1 120px}}
.math-book{max-width:1000px;margin:auto}.math-book-heading{display:flex;align-items:center;justify-content:space-between;gap:24px;margin:25px 0}.math-book-heading h1{font-size:34px;margin:6px 0}.math-book-heading p{color:#736981;margin:8px 0}.math-page-finder{padding:24px;display:flex;align-items:center;gap:28px;flex-wrap:wrap}.math-book-choices{display:flex;gap:8px}.math-book-choices button{min-width:125px;min-height:48px}.math-page-finder form{flex:1;min-width:230px}.math-page-finder form label{display:block;font-size:14px;font-weight:650;margin-bottom:8px}.math-page-finder form>div{display:flex;gap:10px}.math-page-finder input{font:inherit;font-size:20px;border:1px solid #cfc6df;border-radius:10px;padding:10px 14px;width:140px;min-width:0;background:white;color:#30283e}.math-continue{flex-basis:100%;text-align:left}.math-open-page{margin-top:30px}.math-page-title{display:flex;align-items:center;justify-content:space-between;gap:20px;margin-bottom:18px}.math-page-title h2{font-size:25px;margin:0}.math-page-title p{color:#736981;margin:6px 0}.math-book-questions{background:white;border:1px solid #e0d9e9;border-radius:18px;padding:8px 28px}.math-book-question{display:grid;grid-template-columns:145px minmax(0,1fr);gap:24px;padding:22px 0;border-bottom:1px solid #e9e4ee}.math-book-question:last-child{border-bottom:0}.math-book-number{font-size:14px;font-weight:700;color:#67519c;padding-top:7px}.math-book-question p{margin:0 0 12px;line-height:1.75;font-size:17px}.math-book-question .math-help{margin:6px 0 0;border:0}.math-book-question .math-help summary{padding:8px 0;min-height:36px;font-size:14px}.math-book-question .math-worked{margin-top:8px;padding:14px 18px}.math-page-navigation{display:flex;justify-content:space-between;gap:12px;align-items:center;margin:20px 0}.math-page-navigation span,.math-page-note{font-size:13px;color:#736981}.math-book-welcome{text-align:center;padding:60px 20px;color:#736981}.math-book-welcome>span{font-size:44px}.math-book-welcome h2{color:#46375c;font-size:24px}.math-book button:focus-visible,.math-book summary:focus-visible{outline:3px solid #967bdf;outline-offset:3px}@media(max-width:650px){.math-book-heading{align-items:start;gap:10px}.math-book-heading h1{font-size:26px}.math-book-heading p{font-size:14px}.math-book-heading>button{font-size:12px;white-space:nowrap}.math-page-finder{padding:18px;gap:18px}.math-book-choices,.math-page-finder form{width:100%}.math-book-choices button{flex:1;min-width:0}.math-page-finder input{flex:1;width:100%}.math-book-questions{padding:0 18px}.math-book-question{grid-template-columns:1fr;gap:8px;padding:18px 0}.math-book-number{padding:0}.math-page-title{align-items:start}.math-page-title h2{font-size:21px}.math-page-navigation{flex-wrap:wrap}.math-page-navigation span{order:3;text-align:center;width:100%}.math-output{max-width:210px}}
.math-explain-intro{background:#e5f2ea;border-radius:10px;padding:12px 15px;margin:6px 0 14px;color:#275641}
.math-explain-intro strong{font-size:15px}.math-explain-intro p{margin:4px 0 0!important;font-size:15px!important;line-height:1.55!important}
.math-explain-steps{padding:0;list-style:none;counter-reset:math-explain;display:grid;gap:12px;margin:0}
.math-explain-steps>li{counter-increment:math-explain;position:relative;background:#fff;border:1px solid #dce9df;border-radius:11px;padding:13px 14px 12px 44px;color:#33483f;min-width:0}
.math-explain-steps>li::before{content:counter(math-explain);position:absolute;left:12px;top:13px;border-radius:50%;background:#51896b;color:white;width:23px;height:23px;display:grid;place-items:center;font-size:12px;font-weight:800}
.math-explain-steps>li>strong{display:block;color:#285d43;font-size:15px;margin-bottom:7px}
.math-explain-steps p{font-size:15px!important;line-height:1.65!important;margin:0 0 7px!important}
.math-explain-calculations{display:grid;gap:7px;margin-top:10px}
.math-explain-calculations p{margin:0!important;background:#f5f8fd;border-left:3px solid #97afd5;border-radius:5px;padding:9px 11px;color:#2f3855;font-weight:600;overflow-wrap:anywhere;font-variant-numeric:tabular-nums}
@media(max-width:650px){.math-explain-steps>li{padding:11px 11px 11px 40px}.math-explain-steps p{font-size:14px!important}.math-explain-calculations p{font-size:14px!important}}
/* Student-first Math navigation */
.math-study{max-width:960px!important;min-width:0;width:100%;overflow-x:clip;padding-bottom:50px}
.math-study-crumbs{display:flex;align-items:center;flex-wrap:wrap;gap:9px;margin:4px 0 22px;color:#857399;font-size:13px}.math-study-crumbs button{background:none;border:0;color:#6743c2;padding:7px 0;font-size:inherit;font-weight:700}.math-study-crumbs strong{color:#332652}
.math-study-heading{padding:0 0 20px;border-bottom:1px solid #eadff3;margin-bottom:22px}.math-study-heading>span{display:inline-block;color:#6848ad;font-size:12px;font-weight:900;letter-spacing:.12em;margin-bottom:7px}.math-study-heading h1{color:#34224e;font-size:clamp(27px,5vw,40px);line-height:1.13;letter-spacing:-.035em;margin:0 0 9px;overflow-wrap:anywhere}.math-study-heading p{font-size:15px;margin:0;color:#706681}
.math-study-grid,.math-study-lessons{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:13px}
.math-study-tile{display:flex;flex-direction:column;align-items:flex-start;gap:13px;text-align:left;background:#fff;border:2px solid #e8def5;border-top:6px solid #9b7af0;border-radius:20px;padding:24px;min-width:0;min-height:175px;box-shadow:0 4px 0 #eae2f3;color:#342552}.math-study-tile:nth-child(3n+2){border-top-color:#f4bd55}.math-study-tile:nth-child(3n){border-top-color:#70c6b1}.math-study-kicker,.math-study-lesson-number{font-size:12px;font-weight:900;letter-spacing:.11em;color:#6b4bb9}.math-study-tile strong{font-size:24px;line-height:1.2}.math-study-tile-link{margin-top:auto;color:#6645bd;font-size:14px;font-weight:800}
.math-study-lesson{display:grid;grid-template-columns:minmax(0,1fr) auto;gap:9px 18px;align-items:center;text-align:left;padding:22px;background:#fff;border:2px solid #e7ddf5;border-radius:17px;color:#36264f;min-height:118px;min-width:0}.math-study-lesson-number{grid-column:1/-1}.math-study-lesson strong{font-size:19px;line-height:1.3}.math-study-lesson>span:last-child{color:#704cc5;font-size:22px}
.math-study-chapter-bottom{display:grid;gap:10px;margin-top:18px}.math-study-chapter-action{display:flex;justify-content:space-between;align-items:center;gap:12px;width:100%;border:1px solid #ded0f0;border-radius:15px;padding:18px 20px;text-align:left;color:#3b2858;background:#f6f0ff}.math-study-chapter-action span:first-child{display:grid;gap:5px}.math-study-chapter-action strong{font-size:17px}.math-study-chapter-action small{color:#76698b;font-size:13px}
.math-study-full-chapter,.math-study-practice,.math-study-learning{margin-top:26px;background:#fff;border:1px solid #e8e0f0;border-radius:19px;padding:24px;min-width:0}.math-study-section-title h2{font-size:23px;margin:0 0 5px;color:#342450}.math-study-section-title p{margin:0 0 19px;font-size:14px}
.math-study-switch{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:7px;background:#f0ebf8;border-radius:13px;padding:6px;margin-bottom:20px}.math-study-switch button{min-width:0;padding:13px 8px;background:transparent;border:0;border-radius:9px;font-weight:800;font-size:14px;color:#625679}.math-study-switch button.selected{background:#6947c4;color:white;box-shadow:0 2px 7px #33205d26}.math-study-main-tabs{grid-template-columns:repeat(3,minmax(0,1fr));margin:2px 0 0}
.math-study-page-form{display:grid;gap:9px;min-width:0}.math-study-page-form label{font-size:14px;font-weight:800;color:#3c3053}.math-study-page-row{display:flex;gap:10px;min-width:0}.math-study-page-row input{flex:1;min-width:0;width:100%;border:2px solid #e3d9ed;border-radius:11px;background:#fff;font:inherit;font-size:17px;padding:13px}.math-study-page-row button{white-space:nowrap;min-height:48px}.math-study-page-form small{font-size:12px;color:#766989;line-height:1.65;overflow-wrap:anywhere}
.math-study-empty{background:#faf8ff;border:1px dashed #e3d8f0;border-radius:12px;padding:17px;margin:20px 0 0;font-size:14px}.math-study-tip,.math-study-found{font-size:13px;background:#eaf8f3;color:#346855;border-radius:12px;padding:12px 14px}.math-study-results{margin-top:22px;min-width:0}.math-study-results-heading{display:flex;align-items:baseline;justify-content:space-between;gap:12px;margin-bottom:10px;flex-wrap:wrap}.math-study-results-heading h3{font-size:19px;color:#392759}.math-study-results-heading span{font-size:12px;color:#82758e}
.math-study-question{padding:20px 0;border-top:1px solid #e9e3f0;min-width:0}.math-study-question-label{color:#7453b4;font-weight:800;font-size:12px;letter-spacing:.02em;margin-bottom:12px}.math-study-prompt p{color:#302742;font-size:17px;line-height:1.6;margin:0 0 12px;overflow-wrap:anywhere}.math-study-question .math-help{margin:8px 0 0}.math-study-question .math-worked{margin-top:10px}
.math-study-docs{display:grid;gap:10px}.math-study-docs a{display:grid;gap:6px;border:1px solid #e7ddf5;background:#fcfaff;border-radius:12px;padding:15px 17px;text-decoration:none;overflow-wrap:anywhere}.math-study-docs a strong{color:#6445bb;font-size:15px}.math-study-docs a span{color:#796f85;font-size:12px}.math-study-extra{border:1px solid #d7c7ee;border-radius:12px;background:#f3edff;padding:15px 20px;margin-top:17px;font-weight:800;color:#6140ad;text-align:left;width:100%}.math-study-back-link{background:transparent;border:0;color:#6541b5;margin-bottom:12px;padding:5px 0}.math-study-lesson-nav{display:flex;align-items:center;justify-content:space-between;flex-wrap:wrap;gap:10px;margin:24px 0}.math-study-lesson-nav button{border:1px solid #e5d9f5;border-radius:10px;background:white;color:#6143aa;font-size:13px;font-weight:800;padding:12px}
.chapter-six-simple-learn{display:grid;gap:18px}.chapter-six-simple-resource{display:grid;gap:9px}.chapter-six-purple-banner{display:flex;align-items:center;justify-content:space-between;gap:12px;padding:18px 20px;border:1px solid #e0d4f3;border-radius:15px;background:#f0eafb;color:#6545a3!important;font-size:18px;font-weight:750;text-decoration:none;box-shadow:none}.chapter-six-purple-banner:focus-visible,.chapter-six-purple-banner:hover{background:#e9dff8}.chapter-six-mini-actions{display:flex;gap:8px;flex-wrap:wrap}.chapter-six-mini-actions :is(a,button){border:1px solid #d9cbea;background:#fff;border-radius:9px;padding:7px 12px;font-size:12px;font-weight:700;color:#6141a8;text-decoration:none;cursor:pointer}
@media(max-width:650px){.math-study{padding-left:16px!important;padding-right:16px!important}.math-study-grid,.math-study-lessons{grid-template-columns:1fr}.math-study-tile{min-height:120px;padding:19px;gap:9px}.math-study-tile strong{font-size:21px}.math-study-lesson{min-height:96px;padding:17px}.math-study-lesson strong{font-size:17px}.math-study-full-chapter,.math-study-practice,.math-study-learning{padding:17px;margin-top:20px}.math-study-page-row button{padding:12px 14px;font-size:13px}.math-study-switch button{font-size:12px;padding:12px 5px}.math-study-main-tabs button{line-height:1.25}.math-study-lesson-nav button{flex:1 1 auto}.math-study-crumbs{margin-bottom:15px}}

/* Contain documents and controls at phone, tablet and desktop widths. */
.math-document-view{box-sizing:border-box;width:100%;min-width:0}
.math-document-frame{width:100%;max-width:100%;min-width:0;contain:inline-size}
.math-document-frame iframe{max-width:100%;height:75dvh}
.math-document-actions>*{box-sizing:border-box;max-width:100%;white-space:normal;text-align:center;overflow-wrap:anywhere}
.math-document-hint{font-size:13px;line-height:1.6;color:#71647d;overflow-wrap:anywhere}
.math-document-mobile{padding:28px 20px;text-align:center;background:#faf7ff;border:1px solid #e2d9ef;border-radius:16px}
.math-document-mobile>span{font-size:36px}.math-document-mobile h2{font-size:23px;margin:12px 0}
.math-document-mobile p{line-height:1.65;max-width:450px;margin:12px auto 20px}
.math-document-mobile>a{display:inline-flex;align-items:center;justify-content:center;min-height:48px;padding:12px 20px;text-decoration:none;border-radius:12px}
.math-study :is(button,a,summary):focus-visible{outline:3px solid #8e74cd;outline-offset:3px}
.math-study :is(.math-study-learning,.math-study-practice,.math-study-full-chapter,.math-study-docs,.math-study-prompt,.math-worked){max-width:100%;box-sizing:border-box;min-width:0}
.math-study .reader-table{max-width:100%;overflow-x:auto;overscroll-behavior-x:contain}
.math-study .math-study-switch button{overflow-wrap:anywhere;min-height:48px}
@media(max-width:650px){.math-document-actions{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:8px}.math-document-actions>*{padding:12px 8px;font-size:14px}.math-document-frame iframe{min-height:280px;height:65dvh}.math-study-crumbs button{max-width:100%;white-space:normal;text-align:left}.math-study-page-row{flex-wrap:wrap}.math-study-page-row input{flex:1 1 120px}.math-study-page-row button{flex:1 1 90px}}
@media(max-width:360px){.math-document-actions{grid-template-columns:1fr}.math-study-main-tabs{grid-template-columns:1fr}.math-study-switch button{font-size:14px}}

/* Quiet document toolbar: two equal actions with generous touch targets. */
.math-document-view .math-study-heading{margin-bottom:16px;padding-bottom:18px}
.math-document-view .math-study-heading h1{font-size:clamp(25px,3.5vw,34px);line-height:1.22;letter-spacing:-.025em}
.math-document-view .math-document-actions{display:flex;justify-content:flex-start;gap:10px;padding:0;margin:0 0 20px}
.math-document-view .math-document-actions .math-document-action{display:inline-flex;align-items:center;justify-content:center;gap:9px;min-height:46px;min-width:110px;flex:0 1 135px;padding:11px 18px;border:1px solid #e2d9ee;border-radius:14px;background:#f6f2fb;color:#654d89;box-shadow:none;transform:none;font:inherit;font-size:15px;font-weight:650;line-height:1.3;cursor:pointer;text-decoration:none;transition:background .15s,border-color .15s}
.math-document-view .math-document-actions .math-document-action:hover{background:#eee7f7;border-color:#cbb9e1;filter:none;transform:none}
.math-document-action svg{width:20px;height:20px;flex-shrink:0}
.math-document-view .math-document-mobile{display:flex;align-items:flex-start;gap:16px;text-align:left;padding:22px;background:#fcfaff;border:1px solid #e9e2f1;border-radius:18px}
.math-document-view .math-document-mobile h2{font-size:19px;font-weight:700;line-height:1.3;margin:0 0 6px;color:#423053}
.math-document-view .math-document-mobile p{font-size:14px;line-height:1.6;margin:0 0 14px;color:#7a6f86;max-width:340px}
.math-document-reader-icon{display:grid;place-items:center;width:42px;height:42px;flex-shrink:0;background:#f0eaf7;color:#977bb5;border-radius:12px}
.math-document-reader-icon svg{width:25px;height:25px}
.math-document-read-link{color:#765599;font-size:14px;font-weight:650;text-decoration:none;display:inline-flex;gap:6px;align-items:center;min-height:44px}
.math-document-read-link:hover{text-decoration:underline}.math-document-open{margin-top:12px}
@media(max-width:650px){.math-document-view .math-document-actions .math-document-action{flex:1 1 0;min-width:0;max-width:180px}.math-document-view .math-document-mobile{padding:20px 16px;gap:12px}.math-document-view .math-study-heading h1{font-size:25px}}
/* Page browsing and a quiet page-selection print menu. */
.math-study-results{scroll-margin-top:20px}.math-study-results-heading>div>span{font-size:13px;color:#82758e}.math-page-output{position:relative}.math-page-print>summary{list-style:none;cursor:pointer;border:1px solid #e2d9ee;border-radius:13px;background:#f6f2fb;color:#654d89;font-size:14px;font-weight:650;padding:11px 20px;min-height:44px}.math-page-print>summary::-webkit-details-marker{display:none}.math-page-print>div{position:absolute;right:0;top:100%;margin-top:8px;width:300px;max-width:calc(100vw - 64px);z-index:5;background:white;border:1px solid #e4d9ef;border-radius:15px;padding:17px;box-shadow:0 10px 30px #39264e20;display:grid;gap:12px}.math-page-print p{font-size:13px;line-height:1.6;margin:0}.math-page-print fieldset{border:0;padding:0;margin:0;min-width:0}.math-page-print legend{font-size:13px;font-weight:700;margin-bottom:8px}.math-print-pages{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:7px;max-height:220px;overflow:auto}.math-print-pages label{display:flex;align-items:center;gap:5px;font-size:13px;min-height:40px;background:#f9f6fc;border-radius:8px;padding:5px}.math-print-pages input{width:17px;height:17px;accent-color:#7656b4}.math-print-quick{display:flex;gap:8px}.math-print-quick button{font:inherit;font-size:12px;background:#f6f2fb;color:#71558e;border:1px solid #e5ddef;border-radius:9px;padding:9px;min-height:40px}.math-page-turns{display:flex;justify-content:space-between;align-items:center;gap:10px;margin:25px 0 6px;padding-top:18px;border-top:1px solid #e8e0f0}.math-page-turns span{font-size:13px;color:#7c6e89}.math-page-turns button{min-height:46px}.math-page-turns button:disabled{opacity:.4;cursor:default}.math-study-page-divider{font-size:18px;margin:30px 0 0;color:#5d4379}.math-study-book-page{min-width:0}.math-study-book-page+.math-study-book-page{border-top:2px solid #e5dbef;margin-top:24px}.math-study-page-row [data-math-open-all]{min-height:48px}
@media(max-width:650px){.math-study-page-row [data-math-open-all]{flex-basis:100%}.math-page-turns{flex-wrap:wrap}.math-page-turns button{flex:1 1 110px;font-size:13px;padding:11px}.math-page-turns span{order:3;flex-basis:100%;text-align:center}.math-page-print>div{right:0}.math-print-pages{grid-template-columns:repeat(3,minmax(0,1fr))}}
/* Keep the established theme; reserve the visual emphasis for the question. */
.math-question-focus .math-study-practice>.math-study-page-form{max-width:440px;margin-bottom:20px}.math-question-focus .math-study-page-form label{font-size:13px;font-weight:600}.math-question-focus .math-study-page-row input{font-size:17px;padding:11px 13px}.math-question-focus .math-study-page-row .primary{font-size:14px;padding:11px 17px;min-height:45px}.math-question-focus .math-study-results-heading{margin-bottom:8px}.math-question-focus .math-study-results-heading h3{font-size:16px;margin:0 0 3px;font-weight:600;color:#76648b}.math-question-focus .math-study-results-heading span{font-size:11px}.math-question-focus .math-study-question-label{font-size:13px;font-weight:650;letter-spacing:0;color:#77618f;margin-bottom:9px}.math-question-focus .math-study-prompt p{font-size:20px;line-height:1.85;color:#302342}.math-question-focus .math-study-question{padding:22px 0}.math-question-focus .math-help{border:0;margin:8px 0 0}.math-question-focus .math-help>summary{font-size:14px;min-height:42px;padding:9px 0}.math-question-focus .math-study-book-page{border:0}.math-question-focus .math-study-page-divider{font-size:15px}.math-question-focus .math-study-results{scroll-margin-top:20px}.math-question-focus .math-study-page-row{flex-wrap:nowrap}.math-question-focus .math-study-page-row input{flex:1;min-width:0}.math-question-focus .math-study-page-row button{flex:0 0 auto}
@media(max-width:650px){.math-question-focus .math-study-prompt p{font-size:19px}.math-question-focus .math-study-practice{padding:18px}.math-question-focus .math-study-page-row .primary{padding:11px 14px}}
.math-question-focus .math-available-pages{display:flex;align-items:center;flex-wrap:wrap;gap:6px;margin-top:11px;font-size:12px;color:#806b92}.math-question-focus .math-available-pages>span{margin-right:3px}.math-question-focus .math-available-pages button{border:1px solid #e4d8f2;background:#faf7ff;color:#70529b;border-radius:8px;padding:6px 9px;font:inherit;min-height:34px;cursor:pointer}.math-question-focus .math-available-pages button[aria-pressed=true]{background:#eee4fb;border-color:#bba3df;color:#513380;font-weight:700}.math-question-focus .math-study-tip{margin-top:20px}.math-question-focus .math-study-lesson-nav{margin-top:22px}
/* Chapter 6 uses the same Math lesson palette and card layout as Chapter 5. */
.chapter-six-page-photo{margin:14px 0 20px;padding:12px;background:#fff;border:1px solid #e4dff3;border-radius:20px;text-align:center}
.chapter-six-page-photo img{display:block;max-width:min(100%,680px);max-height:780px;width:auto;height:auto;margin:auto;border-radius:10px;object-fit:contain}
.chapter-six-page-photo figcaption{font-size:13px;color:#716984;margin-top:9px}
.chapter-six-page-key{margin:16px 0 24px;background:#f4f0ff;border:1px solid #dbd1f5;border-radius:18px;overflow:hidden}
.chapter-six-page-key summary{cursor:pointer;padding:17px 20px;color:#49357e;font-weight:750;list-style:none;display:flex;justify-content:space-between;gap:10px;align-items:center}
.chapter-six-page-key summary::-webkit-details-marker{display:none}
.chapter-six-page-key[open] summary{border-bottom:1px solid #dbd1f5}
.chapter-six-answer-list{display:grid;grid-template-columns:1fr;gap:12px;padding:16px}
.chapter-six-answer-list>div{background:#fff;border:1px solid #e3dcf4;border-radius:12px;padding:13px}
.chapter-six-key-card .math-explain-intro{margin:0 0 8px}
.chapter-six-key-card .math-explain-intro:first-child{background:#f5f3ff;border-radius:9px;padding:12px}
.chapter-six-key-card .math-integer-line{max-width:760px}
.chapter-six-answer-list strong{color:#57439b}
.chapter-six-answer-list p{margin:5px 0 0;line-height:1.55}
.chapter-six-page-key>p{padding:0 17px 15px;margin:0;color:#615878;font-size:13px}
.math-integer-line{margin:14px 0 6px;padding:10px 12px;background:#f7f9ff;border:1px solid #dce4fa;border-radius:14px;overflow:hidden}
.math-integer-line svg{display:block;width:100%;height:auto;min-height:98px}
.math-integer-line figcaption{font-size:.8rem;line-height:1.4;color:#475569;margin-top:3px}
@media(max-width:600px){.chapter-six-answer-list{grid-template-columns:1fr}.chapter-six-page-photo{padding:7px}.chapter-six-page-key summary{padding:16px}}
/* Chapter 6 page is a single crisp vector sheet, not a nested PDF viewport. */
.chapter-six-page-photo{padding:0;margin:10px auto 16px;border:0;background:transparent;max-width:790px;box-shadow:none}
.chapter-six-page-photo img{display:block;width:100%;max-width:100%;max-height:none;height:auto;border:1px solid #e5e0ed;border-radius:8px;box-shadow:0 7px 19px #32245212}
.chapter-six-page-photo figcaption{padding:11px 3px 0;font-weight:650}
.chapter-six-page-photo figcaption a{color:#6550b8}
.ch6-watch{margin:18px 0 24px;padding:18px;border:1px solid #ddd8f4;border-radius:22px;background:linear-gradient(135deg,#faf8ff,#f1fbf8);box-shadow:0 6px 24px #3830640c}
.ch6-watch-head{display:flex;align-items:flex-start;justify-content:space-between;gap:12px;margin-bottom:15px}
.ch6-watch-kicker{font-size:.75rem;letter-spacing:.09em;font-weight:800;color:#6754a4}
.ch6-watch-head h2{margin:5px 0 4px;font-size:clamp(1.3rem,3vw,1.65rem);color:#30324b}
.ch6-watch-head p{margin:0;color:#656579;font-size:.92rem;line-height:1.45}
.ch6-watch-count{white-space:nowrap;border-radius:999px;background:#e7e0fc;color:#55458b;padding:7px 10px;font-size:.75rem;font-weight:800}
.ch6-watch-layout{display:grid;grid-template-columns:minmax(0,1.25fr) minmax(0,1fr);gap:16px}
.ch6-watch-stage,.ch6-watch-list{min-width:0}
.ch6-watch-screen{aspect-ratio:16/9;overflow:hidden;border-radius:16px;background:#242640}
.ch6-watch-screen iframe{width:100%;height:100%;border:0;display:block}
.ch6-watch-poster{height:100%;display:flex;flex-direction:column;align-items:center;justify-content:center;text-align:center;gap:8px;padding:16px;color:white;background:radial-gradient(circle at 22% 20%,#6256a4,#242640 72%)}
.ch6-watch-poster>span{display:grid;place-items:center;width:55px;height:55px;background:#fff3;border:1px solid #fff6;border-radius:50%;font-size:1.3rem}
.ch6-watch-poster strong{font-size:1.1rem}.ch6-watch-poster small{color:#e0dff2}
.ch6-watch-details{display:flex;flex-direction:column;gap:3px;margin:11px 0;color:#323650}.ch6-watch-details small{color:#6a6b7b}
.ch6-watch-controls{display:flex;gap:7px}.ch6-watch-controls button{flex:1;min-height:40px;border-radius:11px;font-size:.83rem;font-weight:800;border:1px solid #d7d4e6;padding:8px}
.ch6-watch-primary{background:#6754a4;color:#fff;border-color:#6754a4!important}.ch6-watch-secondary{background:#fff;color:#504a74}.ch6-watch-controls button:disabled{opacity:.4;cursor:not-allowed}
.ch6-shelf-quiz{display:flex;align-items:center;justify-content:space-between;gap:18px;margin:18px 0 22px;padding:20px;border:2px solid #d8c2fa;border-radius:20px;background:linear-gradient(115deg,#f6eaff,#fff8dc);box-shadow:0 5px 0 #e8dcf8}.ch6-shelf-quiz h2{font-size:19px;margin:5px 0}.ch6-shelf-quiz p{font-size:13px;margin:0;max-width:560px}.ch6-shelf-quiz-kicker{color:#6941a5;font-size:11px;letter-spacing:.07em;font-weight:900}.ch6-shelf-quiz-button{flex-shrink:0;border:2px solid #5b399a;background:#7350d7;color:#fff;border-radius:13px;min-height:50px;padding:12px 17px;font-size:14px;font-weight:900}.ch6-shelf-quiz-button:hover:not(:disabled){background:#5e37c2}.ch6-shelf-quiz-button:disabled{background:#e9e2f1;border-color:#d6cede;color:#685c78;opacity:1;cursor:not-allowed}.math-study-full-chapter>.math-study-chapter-bottom{margin-top:18px;padding-top:16px;border-top:1px solid #e7def6}@media(max-width:680px){.ch6-shelf-quiz{flex-direction:column;align-items:stretch;padding:16px}.ch6-shelf-quiz-button{width:100%}}
.ch6-chapter-quizzes{margin:24px 0}.ch6-chapter-quiz-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:12px}.ch6-chapter-quiz-grid button{display:flex;flex-direction:column;align-items:flex-start;text-align:left;gap:8px;padding:20px;border:2px solid #cdb8f5;border-radius:18px;background:#f6efff;color:#3f2b69;min-height:150px}.ch6-chapter-quiz-grid button strong{font-size:17px}.ch6-chapter-quiz-grid button span{font-size:11px;font-weight:900;letter-spacing:.08em}.ch6-chapter-quiz-grid button small{font-size:12px;font-weight:800;color:#6551a7}.ch6-chapter-quiz-grid button:disabled{background:#f4f1f8;color:#746b86;opacity:1;cursor:not-allowed}.ch6-chapter-quiz-grid button:hover:not(:disabled){background:#ebddff;border-color:#8255dc}.math-study-chapter-bottom[aria-label="Chapter 6 review and original PDF resources"]{margin-top:24px}@media(max-width:680px){.ch6-chapter-quiz-grid{grid-template-columns:1fr}}
.ch6-watch-note{font-size:.74rem;color:#717082;margin:9px 0 0;line-height:1.35}
.ch6-watch-list{display:grid;gap:8px;align-content:start}
.ch6-watch-item{display:flex;align-items:center;gap:10px;width:100%;text-align:left;text-decoration:none;border:1px solid #e2e2ed;border-radius:13px;padding:10px;background:white;color:#39394b}
.ch6-watch-item:hover,.ch6-watch-item:focus-visible{background:#f5f1ff;border-color:#8d7ccc;outline-offset:2px}
.ch6-watch-item.selected{background:#eeeafd;border-color:#8d7ccc;box-shadow:0 0 0 1px #8d7ccc55}
.ch6-watch-item>span:nth-child(2){flex:1;min-width:0;display:flex;flex-direction:column;gap:3px}
.ch6-watch-item b{font-size:.83rem;line-height:1.25}.ch6-watch-item small{font-size:.72rem;color:#77748d}
.ch6-watch-number{flex:none;display:grid;place-items:center;width:29px;height:29px;border-radius:9px;background:#e5e6f3;color:#5a527e;font-weight:800;font-size:.8rem}
@media(max-width:730px){.ch6-watch{padding:13px;border-radius:17px}.ch6-watch-layout{grid-template-columns:1fr}.ch6-watch-head{flex-wrap:wrap}.ch6-watch-list{grid-template-columns:1fr 1fr}.ch6-watch-item{padding:9px;gap:7px}.ch6-watch-controls button{font-size:.76rem;padding:8px 4px}}
@media(max-width:440px){.ch6-watch-list{grid-template-columns:1fr}.ch6-watch-controls{gap:5px}.ch6-watch-head h2{font-size:1.34rem}}