@charset "UTF-8";
:root{--ink:#16384c;--muted:#5d707b;--green:#176b61;--line:#dce5e5;--paper:#f5f7f6;--white:#fff;--soft:#eaf2ef;--gold:#b48237;font-family:"Segoe UI","Microsoft JhengHei",sans-serif;color:var(--ink);background:var(--paper);font-synthesis:none}
*{box-sizing:border-box}body{margin:0}a{color:inherit}button,input,select{font:inherit}button,a,input,select{touch-action:manipulation}button{cursor:pointer}a{text-decoration:none}a:hover{text-decoration:underline}a:focus-visible,button:focus-visible,input:focus-visible,select:focus-visible,summary:focus-visible{outline:3px solid #be8228;outline-offset:4px}h1,h2,h3,p{margin-top:0}p{line-height:1.8}h1{font-size:clamp(2rem,4vw,3.4rem);line-height:1.3;letter-spacing:-.04em}h2{font-size:1.5rem}h3{font-size:1.08rem;line-height:1.6}small{line-height:1.7}.container{width:min(1200px,calc(100% - 64px));margin:auto}.skip{position:absolute;left:20px;top:-100px;padding:12px;background:white;z-index:20}.skip:focus{top:10px}.site-header{background:white;border-bottom:1px solid var(--line)}.header-inner{max-width:1320px;margin:auto;min-height:94px;padding:18px 32px;display:flex;align-items:center;gap:48px}.brand{display:flex;align-items:center;gap:12px;font-size:21px;letter-spacing:.1em;font-weight:750;white-space:nowrap}.brand-mark{font:38px Georgia,serif;background:var(--ink);color:white;width:47px;height:49px;border-radius:11px;display:grid;place-items:center}.brand-sub{display:block;font-size:11px;letter-spacing:.13em;margin-top:3px;color:var(--muted);font-weight:500}nav{display:flex;gap:30px;align-self:stretch;align-items:center}nav a{font-size:14px;position:relative;padding:12px 0;white-space:nowrap}nav a[aria-current]{color:var(--green);font-weight:750}nav a[aria-current]:after{content:"";position:absolute;height:3px;bottom:0;left:0;right:0;background:var(--green);border-radius:3px}.legacy-link{margin-left:auto;font-size:13px;color:var(--muted);white-space:nowrap}.hero{display:grid;grid-template-columns:1.3fr .7fr;gap:50px;padding:64px 0 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#b7cdca;padding:2px}.math-art{height:290px;border-radius:22px;background:#e5eeeb;position:relative;overflow:hidden;border:1px solid #d5e2dc}.math-art:before{content:"";position:absolute;inset:0;background-image:linear-gradient(#c5d7d14d 1px,transparent 1px),linear-gradient(90deg,#c5d7d14d 1px,transparent 1px);background-size:25px 25px}.math-art svg{width:100%;height:100%;position:relative}.art-note{position:absolute;bottom:15px;left:20px;font-size:10px;letter-spacing:.18em;color:#527769}.stats{display:flex;gap:40px;padding:22px 0;border-top:1px solid var(--line);border-bottom:1px solid var(--line);margin-bottom:44px}.stat strong{font-size:24px;margin-right:10px;font-weight:650}.stat span{font-size:12px;color:var(--muted)}.section-head{display:flex;justify-content:space-between;gap:18px;align-items:end;margin-bottom:22px}.section-head h2{margin-bottom:8px}.section-head p{font-size:13px;color:var(--muted);margin:0}.section-head>a{font-size:13px;color:var(--green);white-space:nowrap}.book-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:16px}.book-card{background:white;border:1px solid var(--line);border-radius:12px;padding:23px;transition:transform .15s,border-color .15s;display:flex;flex-direction:column;min-height:200px}.book-card:hover{transform:translateY(-3px);border-color:var(--green);text-decoration:none}.book-top{display:flex;justify-content:space-between;align-items:center;margin-bottom:18px}.book-number{font:italic 28px Georgia,serif;color:var(--green)}.book-type{font-size:10px;color:var(--muted);border:1px solid var(--line);border-radius:4px;padding:4px 7px}.book-card h3{margin-bottom:8px}.book-card p{font-size:12px;color:var(--muted);margin:0 0 18px;line-height:1.8}.book-bottom{margin-top:auto;display:flex;justify-content:space-between;font-size:11px;color:var(--green)}.home-section{margin-bottom:48px}.feature-grid{display:grid;grid-template-columns:1fr 1fr;gap:20px}.feature{padding:28px 30px;border-radius:12px;background:var(--ink);color:white;position:relative}.feature.light{background:var(--soft);color:var(--ink);border:1px solid #d5e2dd}.feature p{font-size:13px;opacity:.85;max-width:390px}.feature a{display:inline-block;font-size:13px;border-bottom:1px solid;padding-bottom:6px}.feature .eyebrow{color:inherit;opacity:.7}.page-intro{padding:40px 0 26px}.breadcrumb{font-size:12px;color:var(--muted);margin-bottom:24px}.page-intro h1{font-size:32px;margin-bottom:10px}.page-intro p{font-size:14px;color:var(--muted);margin:0}.browse-layout{display:grid;grid-template-columns:218px minmax(0,1fr);gap:34px;margin-bottom:50px}.sidebar{align-self:start;position:sticky;top:24px;background:white;border:1px solid var(--line);border-radius:12px;padding:20px}.sidebar summary{font-weight:700;cursor:pointer;list-style:none;font-size:14px}.side-links{display:flex;flex-direction:column;gap:5px;margin-top:16px}.side-links a{padding:10px 12px;border-radius:6px;font-size:13px}.side-links a.active{background:var(--soft);color:var(--green);font-weight:700}.side-links a small{float:right;font-size:10px}.side-label{font-size:10px;letter-spacing:.14em;color:var(--muted);border-top:1px solid var(--line);padding-top:18px;margin-top:20px}.chapter-links a{font-size:12px}.filters{background:white;border:1px solid var(--line);border-radius:10px;padding:16px;display:flex;gap:12px;flex-wrap:wrap;margin-bottom:22px;align-items:end}.field{display:flex;flex-direction:column;gap:7px;flex:1;min-width:110px}.field.wide{flex:2;min-width:180px}.field label{font-size:11px;font-weight:700;color:var(--muted)}.field input,.field select{width:100%;border:1px solid #c8d6d5;border-radius:5px;min-height:40px;padding:8px 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td:first-child{font-size:18px;font-weight:700}.exam-table .download{margin:0 5px 5px 0}.search-results{max-width:920px;margin:auto}.search-results .filters{margin-top:10px}.loading{padding:80px;text-align:center}.site-footer{margin-top:48px;border-top:1px solid var(--line);background:white;padding:32px 0}.footer-inner{display:flex;justify-content:space-between;gap:30px;font-size:12px}.footer-inner strong{font-size:14px}.footer-inner p{margin:8px 0;color:var(--muted)}.footer-inner>div:last-child{text-align:right;color:var(--muted);display:flex;flex-direction:column;gap:6px}.footer-inner small{font-size:10px}
@media(prefers-reduced-motion:reduce){*{transition:none!important;scroll-behavior:auto!important}}
@media(max-width:650px){.art-note{display:none}.exam-table{min-width:0!important;display:block}.exam-table thead{display:none}.exam-table tbody{display:block}.exam-table tr{display:grid;grid-template-columns:70px 1fr 28px;border-bottom:1px solid var(--line)}.exam-table td{border-top:0!important;padding:12px!important}.exam-table td:first-child:after{content:' 年';font-size:11px;font-weight:400}.exam-table td:last-child{grid-column:1/-1;padding-top:0!important}.exam-table td:nth-child(3){padding-left:0!important}.exam-wrap{overflow:visible}}
@media(max-width:1000px){.header-inner{gap:24px}nav{gap:18px}.hero{gap:24px}.book-grid{grid-template-columns:repeat(2,1fr)}.browse-layout{gap:20px;grid-template-columns:180px minmax(0,1fr)}.sidebar{padding:15px}.legacy-link{display:none}}
@media(max-width:650px){.container{width:calc(100% - 32px)}.header-inner{padding:16px;flex-wrap:wrap;gap:16px;min-height:0}.brand{font-size:18px}.brand-mark{width:38px;height:40px;font-size:30px}nav{width:100%;gap:0;justify-content:space-between}nav a{font-size:13px;padding:9px 0}.hero{grid-template-columns:1fr;padding:35px 0 28px;gap:25px}.hero h1{font-size:34px}.hero p{font-size:14px}.math-art{height:185px}.eyebrow{margin-bottom:15px}.search-box button{padding:10px 16px}.search-box input{font-size:13px;padding:10px 6px}.stats{gap:0;justify-content:space-between;margin-bottom:30px;padding:17px 0}.stat strong{display:block;font-size:23px}.stat span{font-size:10px}.book-grid{gap:10px}.book-card{padding:17px;min-height:190px}.book-type{font-size:9px}.book-card p{font-size:11px}.section-head{align-items:start}.section-head h2{font-size:21px}.section-head p{font-size:12px}.feature-grid{grid-template-columns:1fr}.feature{padding:24px}.page-intro{padding:28px 0 22px}.page-intro h1{font-size:28px}.browse-layout{grid-template-columns:1fr;gap:20px}.sidebar{position:static}.side-links{display:grid;grid-template-columns:1fr 1fr}.chapter-links{grid-template-columns:1fr}.sidebar summary:after{content:' ＋';float:right}.filters{padding:13px;gap:10px}.field{min-width:110px}.field.wide{flex-basis:100%}.lesson{padding:17px}.lesson-top{display:block}.source-link{display:inline-block;margin-bottom:12px}.lesson-actions{gap:7px}.download{font-size:11px;padding:9px}.footer-inner{display:block}.footer-inner>div:last-child{text-align:left;margin-top:18px}.notice{font-size:11px}.result-bar{gap:12px}.exam-table th,.exam-table td{padding:13px}.pagination{gap:12px}.pagination a{padding:9px 12px}}
.related-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:20px;margin-bottom:24px}.related-card{background:white;border:1px solid var(--line);border-radius:12px;padding:25px;display:flex;flex-direction:column;min-height:210px}.related-card h2{font-size:19px;line-height:1.6;overflow-wrap:anywhere}.related-card p{color:var(--muted);font-size:12px;overflow-wrap:anywhere}.related-card .book-bottom{margin-top:auto}.related-card[href]:hover{border-color:var(--green);text-decoration:none;background:#fbfdfc}.column-intro{padding:32px;background:var(--soft);border-radius:14px;display:flex;align-items:center;gap:28px;margin-bottom:28px}.column-symbol{font:64px Georgia,serif;color:var(--green)}.column-intro h2{margin-bottom:10px}.column-intro p{margin-bottom:0;font-size:14px;color:var(--muted)}.external-note{font-size:12px;color:var(--muted);margin:20px 0 40px}.header-inner{gap:30px}nav{gap:22px}
@media(max-width:1000px){.header-inner{flex-wrap:wrap}.header-inner nav{order:3;width:100%;justify-content:space-between}.related-grid{grid-template-columns:repeat(2,minmax(0,1fr))}}
@media(max-width:650px){.header-inner nav{display:grid;grid-template-columns:repeat(3,1fr);gap:3px 18px}.header-inner nav a{text-align:center}.related-grid{grid-template-columns:1fr;gap:14px}.column-intro{padding:24px;gap:18px}.column-intro h2{font-size:20px}.column-symbol{font-size:44px}.related-card{min-height:190px}}