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.video-section{margin-top:20px}:where(.math-scope) .comparison-row.long{max-width:270px}}@media(max-width:380px){:where(.math-scope) .wrap{width:calc(100% - 28px)}:where(.math-scope) .catalogue-hero h1{font-size:35px}:where(.math-scope) .book-name{font-size:20px}:where(.math-scope) .fold-label{font-size:14px}:where(.math-scope) .counter-board{gap:8px}:where(.math-scope) .warmup,:where(.math-scope) .example,:where(.math-scope) .quiz-shell{padding:18px}:where(.math-scope) .unit-row{grid-template-columns:minmax(0,1fr) 60px}:where(.math-scope) .unit-name{font-size:16px}:where(.math-scope) .pair-column .dot{width:32px;height:32px}:where(.math-scope) .pairs{gap:6px}:where(.math-scope) .primary,:where(.math-scope) .secondary,:where(.math-scope) .next-step{padding:10px 16px}:where(.math-scope) .quiz-topline{font-size:14px}}@media(prefers-reduced-motion:reduce){.math-scope{scroll-behavior:auto}:where(.math-scope) *,:where(.math-scope) *:before,:where(.math-scope) *:after{animation:none!important;transition:none!important}}

/* 公共布局与讲义正文的边界；不改变#topnav或footer.site。 */
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