.radical-page{max-width:880px}.radical-page math{font-family:"Cambria Math","STIX Two Math",math;font-size:1.12em;white-space:nowrap;overflow-wrap:normal;line-height:normal}.radical-page .math-line{font-size:20px;line-height:2.15;margin:14px 0;overflow-x:auto;padding:4px 2px 9px;max-width:100%}.radical-page .math-line math{font-size:1.06em}.opening-rule{padding:24px 28px;margin:26px 0;border:2px solid var(--blue);border-radius:22px 22px 8px 22px;background:var(--paper)}.opening-rule h2{font-size:23px}.opening-equations{display:grid;grid-template-columns:1fr 1fr;gap:20px;margin:20px 0}.opening-equations>div{display:flex;align-items:flex-start;flex-direction:column;gap:12px}.opening-equations math{font-size:32px}.opening-equations span{font-size:16px;color:var(--muted)}.opening-rule>p,.edition-line{font-size:16px;color:var(--muted)}.chapter-cards{display:grid;gap:24px}.chapter-card{padding:0;overflow:hidden}.chapter-card>header{padding:22px 26px 20px;background:#f7faff;border-bottom:1px solid var(--line)}.chapter-card .period{font-size:16px;color:var(--teal);font-weight:700;margin-bottom:5px}.chapter-card h3{color:var(--ink);font-size:24px;margin:0;line-height:1.55}.card-subtitle{color:var(--muted);margin-top:8px!important}.card-content{padding:6px 26px 26px}.card-content h4{font-size:18px;line-height:1.5;margin:22px 0 10px;color:var(--teal)}.radical-page .chapter-card p,.radical-page .chapter-card li{font-size:18px}.chapter-card li+li{margin-top:10px}.chapter-card ul{margin:8px 0 0;padding-left:1.25em}.pitfall{margin-top:24px;padding:0 18px 18px;background:#fff9e8;border-left:4px solid #c6a44d;border-radius:0 8px 8px 0}.pitfall h4{padding-top:16px;color:#775400}.radical-page .chapter-example{padding:26px}.chapter-example h3{font-size:23px}.example-question>p{margin:10px 0}.example-steps{padding:0;list-style:none;counter-reset:step}.example-steps>li{position:relative;counter-increment:step;padding:20px 20px 20px 50px;background:var(--wash);border-left:3px solid #bacaf6;margin:12px 0;border-radius:0 8px 8px 0}.example-steps>li:before{content:counter(step);position:absolute;left:16px;top:20px;color:var(--action);font-weight:700}.example-steps p{font-size:18px}.example-steps p+p{margin-top:10px}.chapter-example .step-count{min-height:26px;font-size:16px}.chapter-example .button-row{margin-top:14px}.chapter-quiz .quiz-topline h3{font-size:18px;margin:0}.input-guide{font-size:16px;color:var(--muted);padding:12px 0 20px;border-bottom:1px solid var(--line);margin-bottom:22px}.question-title{font-size:17px;color:var(--teal);margin-bottom:10px}.question-prompt{font-size:21px;line-height:1.8}.question-prompt p{margin-bottom:12px}.question{padding:4px 0 18px}.question+.question{border-top:1px solid var(--line);padding-top:24px}.chapter-quiz[data-ready="true"] .question{border-top:0;padding-top:4px}.chapter-quiz .choice{display:flex;align-items:center;gap:14px;min-height:56px;font-size:19px}.choice-letter{font-size:16px;font-weight:700;color:var(--muted);flex:none}.choice[aria-pressed="true"] .choice-letter{color:var(--action)}.chapter-quiz .answer-field{display:block;margin-bottom:12px}.chapter-quiz .answer-field label{display:block;font-size:17px;margin-bottom:8px}.chapter-quiz .answer-field input{width:100%;font-size:20px;min-height:56px}.chapter-quiz input::placeholder{font-size:16px;color:#61758b;opacity:1}.symbol-keys{display:flex;flex-wrap:wrap;gap:8px;margin:12px 0 18px}.symbol-key{font-size:16px;min-height:48px;padding:8px 13px;border:1px solid #b7c9de;border-radius:7px;background:var(--wash);color:var(--ink)}.symbol-key:disabled{color:var(--muted)}.worked-solution{font-size:18px;padding:12px 16px;border:1px solid var(--line);border-radius:8px;background:#f7faff;margin:18px 0}.worked-solution>summary{font-size:17px;font-weight:700;min-height:34px;cursor:pointer;color:var(--action)}.worked-solution>div{padding:12px 0 0}.chapter-quiz .feedback{font-size:18px;line-height:1.8}.quiz-controls>button{min-width:120px}.chapter-quiz .score{font-size:38px}.result-review{padding-left:24px;font-size:17px}.result-review li{padding:10px 0;border-bottom:1px solid var(--line)}.result-review li::marker{color:var(--muted)}.result-review .review-status{font-weight:700}.result-review .review-answer{display:block;margin-top:6px}.result-review .review-method{display:block;color:var(--muted);font-size:16px;margin-top:5px}.chapter-navigation{display:grid;grid-template-columns:1fr 1fr;gap:18px;margin:38px 0}.chapter-navigation>div{padding:18px;border:1px dashed #aabed4;border-radius:10px;background:#f7faff;display:flex;gap:8px;flex-direction:column}.chapter-navigation span{font-size:16px;color:var(--muted)}.chapter-navigation strong{font-size:18px;font-weight:700}.source-note{font-size:16px;line-height:1.85;margin:24px 0}.source-note summary{cursor:pointer;min-height:48px;color:var(--action);padding:10px 0}.source-note p{margin:12px 0}.radical-page :target{scroll-margin-top:20px}@media(max-width:760px){.opening-rule{padding:22px 20px}.opening-equations{grid-template-columns:1fr;gap:22px}.opening-equations>div{gap:8px}.opening-equations math{font-size:29px}.chapter-card>header{padding:20px}.chapter-card h3{font-size:22px}.card-content{padding:0 20px 20px}.pitfall{padding-inline:14px}.radical-page .chapter-example{padding:20px}.chapter-example h3{font-size:22px}.example-steps>li{padding:16px 14px 16px 36px}.example-steps>li:before{left:12px;top:16px}.radical-page .math-line{font-size:19px;padding-bottom:10px}.chapter-navigation{grid-template-columns:1fr}.question-prompt{font-size:20px}.chapter-quiz .choice{padding:12px;gap:12px;font-size:18px}.worked-solution{padding:12px}.radical-page .lesson-route a{font-size:16px;padding:8px 11px}.chapter-card .math-line{font-size:19px}}@media(max-width:380px){.chapter-card>header{padding:18px}.card-content{padding-inline:18px}.radical-page .chapter-example{padding:18px}.radical-page .chapter-card p,.radical-page .chapter-card li{font-size:18px}.radical-page .math-line{font-size:18px}.radical-page math{font-size:1.07em}.example-steps>li{padding-left:32px}.example-steps>li:before{left:9px}.chapter-quiz .choice{font-size:17px}.radical-page .lesson-route{gap:7px}.radical-page .lesson-route a{padding:8px 10px}}@media(prefers-reduced-motion:reduce){.radical-page *{scroll-behavior:auto}}

.lesson-figure{margin:22px auto 6px;max-width:420px;padding:14px 14px 10px;background:#fff;border:1px solid var(--line);border-radius:12px}.lesson-figure svg{display:block;width:100%;height:auto}.lesson-figure figcaption{font-size:16px;color:var(--muted);line-height:1.7;margin-top:8px;text-align:center}.lesson-figure text{font-family:"Cambria Math","STIX Two Math",serif;font-style:italic;font-size:17px;fill:var(--ink,#17304d)}.lesson-figure .shape{fill:#eef5ff;stroke:var(--blue,#2f6fdc);stroke-width:2.5;stroke-linejoin:round}.lesson-figure .diag{stroke:#7d93ad;stroke-width:1.8;stroke-dasharray:6 5}.lesson-figure .mid{stroke:var(--teal,#0f7f7a);stroke-width:2.6}.lesson-figure .pt{fill:var(--ink,#17304d)}.lesson-figure .tick line{stroke:var(--teal,#0f7f7a);stroke-width:2}.lesson-figure .right polyline{fill:none;stroke:#7d93ad;stroke-width:1.6}.lesson-figure .node rect{fill:#eef5ff;stroke:var(--blue,#2f6fdc);stroke-width:2}.lesson-figure .node rect.hl{fill:#fff4d6;stroke:#c6a44d}.lesson-figure .nodetext text{font-family:inherit;font-style:normal;font-size:16px;font-weight:700}.lesson-figure .arrow line{stroke:#7d93ad;stroke-width:1.8}.lesson-figure .edge text{font-family:inherit;font-style:normal;font-size:16px;fill:var(--muted,#5b6f86);paint-order:stroke;stroke:#fff;stroke-width:3px;stroke-linejoin:round}

/* 已上线的相邻单元用链接卡片（与 div 卡片同尺寸），与 ch20 一致 */
.chapter-navigation>a{padding:18px;border:1px solid #aabed4;border-radius:10px;background:#fff;display:flex;gap:8px;flex-direction:column;color:inherit;text-decoration:none}.chapter-navigation>a:hover,.chapter-navigation>a:focus-visible{border-color:var(--blue)}

/* 本地数学情境插图，沿用讲义字体与配色变量。 */
.math-scope .math-illus{width:640px;max-width:100%;min-width:0;margin:22px auto}
.math-scope .math-illus img{display:block;width:100%;max-width:100%;height:auto;border:1px solid var(--line);border-radius:12px;background:var(--paper)}
.math-scope .math-illus figcaption{margin-top:8px;color:var(--muted);font-size:15px;line-height:1.7;text-align:center;overflow-wrap:anywhere}
.math-scope .chapter-card .math-illus,.math-scope .chapter-example .math-illus{width:480px}