:root{--ink:#252525;--gray:#666;--line:#ddd;--paper:#f0f0f0;--yellow:#f2da55;--orange:#eb610f;--blue:#27499d;--header:90px;--gutter:clamp(24px,5vw,96px)}*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:var(--header)}body{margin:0;color:var(--ink);background:#fff;font:400 16px/1.7 MiSans,'Microsoft YaHei',sans-serif}a{color:inherit;text-decoration:none}button{font:inherit;color:inherit;cursor:pointer}button,a{touch-action:manipulation}button:focus-visible,a:focus-visible{outline:3px solid var(--ink);outline-offset:5px}[hidden]{display:none!important}h1,h2,h3,p{margin:0}h1,h2,h3{font-weight:600}img{display:block;max-width:100%;height:auto}.site-header{height:var(--header);position:sticky;top:0;background:#fffffff5;z-index:30;border-bottom:1px solid var(--line)}.header-inner{height:100%;padding:0 var(--gutter);max-width:1920px;margin:auto;display:flex;align-items:center;gap:36px}.wordmark{font-size:27px;font-weight:700;white-space:nowrap;letter-spacing:-.4px}nav{display:flex;margin-left:auto;gap:clamp(25px,3.6vw,68px)}nav a{font-weight:500;font-size:14px;padding:12px 0;position:relative;white-space:nowrap}nav a:after{content:'';height:3px;background:var(--yellow);position:absolute;left:0;right:0;bottom:3px;transform:scaleX(0);transform-origin:left;transition:transform .2s}nav a:hover:after,nav a[aria-current]:after{transform:scaleX(1)}.pill{display:inline-flex;align-items:center;justify-content:center;border:0;background:var(--ink);color:#fff;font-size:15px;font-weight:500;padding:14px 30px;min-width:148px;min-height:50px;border-radius:999px;white-space:nowrap}.pill:hover{background:#444}.header-cta{margin-left:12px;font-size:13px;min-width:138px;padding:12px 26px;min-height:44px}.page-section{scroll-margin-top:0;max-width:1920px;margin:auto}.hero{min-height:calc(100svh - 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/* v17第二屏无外层标题和留边，背景由图谱统一。 */
.mathematics.page-section{max-width:none;padding:0;background:#f0f0f0;min-height:0}.mathematics iframe{width:100%;height:900px;min-height:0;display:block;border:0;background:#f0f0f0}@media(max-width:760px){.mathematics.page-section{padding:0}.mathematics iframe{height:1150px}}

/* v26：照片保留真实边缘，橙色细线移至右侧栏目标签；教辅分成两屏。 */
.author-photo{border-top:0}.author-copy>.section-kicker{display:inline-block;border-top:4px solid #EB610F;padding-top:12px}.book-series-label{display:flex;align-items:center;gap:16px;border-bottom:1px solid #ddd;padding:10px 0 16px;margin-bottom:30px}.book-series-label h3{font-size:18px;font-weight:500}.book-series-label span{font-size:12px;color:#666}.books-junior{background:#fff}.books-junior .book-series-statement{background:#f0f0f0}
@media(max-width:760px){.book-series-label{margin-bottom:24px;padding-top:0}.book-series-label h3{font-size:16px}#books-title{font-size:27px}}

/* v27：初高中教辅位于同一背景和同一模块内。 */
.junior-books-group{margin-top:64px;scroll-margin-top:110px}.junior-books-group .book-series-statement{background:#fff}.junior-books-group .book-series-statement img{max-height:260px}
@media(max-width:760px){.junior-books-group{margin-top:38px;scroll-margin-top:132px}.junior-books-group .book-series-statement img{position:static;width:100%;height:210px;opacity:1;max-height:none;margin-top:12px;object-fit:contain}}