:root{--ink:#203344;--muted:#61717a;--paper:#fcfbf8;--card:#fff;--line:#dce4e4;--accent:#196b6b;--soft:#eef6f3;--warm:#f7ecd9;--font:18px;--side:270px}
*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:94px}body{margin:0;background:var(--paper);color:var(--ink);font-family:system-ui,-apple-system,"PingFang SC","Microsoft YaHei","Noto Sans CJK SC",sans-serif;font-size:var(--font);line-height:1.85}a{color:var(--accent);text-decoration-thickness:1px;text-underline-offset:4px}a:hover{color:#943e20}button,input,select{font:inherit}button{cursor:pointer}button:focus-visible,a:focus-visible,input:focus-visible,select:focus-visible{outline:3px solid #c38032;outline-offset:3px}button{border:1px solid var(--line);border-radius:7px;background:#fff;color:var(--ink);padding:7px 13px}.top{height:72px;position:sticky;top:0;z-index:30;display:flex;align-items:center;gap:18px;padding:0 24px;background:rgba(252,251,248,.98);border-bottom:1px solid var(--line)}.brand{font-size:16px;font-weight:750;text-decoration:none;color:var(--ink);white-space:nowrap}.top nav{display:flex;gap:22px;margin-left:auto;font-size:14px}.top nav a{text-decoration:none}.tools{display:flex;gap:5px}.tools button{font-size:13px;padding:5px 9px}.layout{display:grid;grid-template-columns:var(--side) minmax(0,1fr);max-width:1530px;margin:auto}.sidebar{height:calc(100vh - 72px);position:sticky;top:72px;overflow-y:auto;padding:28px 18px 60px 22px;border-right:1px solid var(--line);font-size:13px;line-height:1.6}.side-label{font-size:11px;letter-spacing:.12em;color:var(--muted);font-weight:700;margin:24px 0 9px}.side-label:first-child{margin-top:0}.sidebar a{display:block;text-decoration:none;padding:6px 9px;color:var(--muted);border-radius:6px}.sidebar a.active{background:var(--soft);color:var(--accent);font-weight:750}.sidebar a:hover{background:#f1f2ed;color:var(--ink)}.side-num{display:inline-block;width:31px;font-variant-numeric:tabular-nums;color:var(--accent);font-size:11px}.main{min-width:0;padding:35px clamp(24px,5vw,88px) 80px}.article{max-width:920px;margin:auto}.eyebrow{font-size:12px;letter-spacing:.16em;font-weight:750;color:var(--accent);margin-bottom:13px}.breadcrumb{font-size:13px;color:var(--muted);margin-bottom:25px}.breadcrumb a{text-decoration:none}h1{font-size:clamp(28px,3vw,40px);line-height:1.4;letter-spacing:-.03em;font-weight:760;margin:0 0 28px}h2{font-size:26px;line-height:1.5;margin:50px 0 20px;padding-top:8px;border-top:1px solid var(--line)}h3{font-size:21px;line-height:1.55;margin:28px 0 13px}h4{font-size:19px;line-height:1.6;margin:25px 0 12px}p{margin:15px 0}strong{font-weight:740}li{margin:8px 0}ul,ol{padding-left:1.5em}.lead{font-size:20px;line-height:1.8;max-width:760px;color:#465762}.muted,.small{color:var(--muted)}.small{font-size:14px}.panel{padding:22px 25px;background:var(--soft);border:1px solid #d7e6de;border-radius:10px;margin:24px 0}.panel.warm{background:var(--warm);border-color:#ecdbbd}.panel h2,.panel h3{border:0;margin:0 0 10px;padding:0}.panel p:last-child{margin-bottom:0}.preq{padding:17px 21px;border-left:4px solid var(--accent);background:#f0f6f3;margin:22px 0;font-size:16px;line-height:1.85}.preq .label{display:block;font-size:12px;letter-spacing:.08em;font-weight:750;color:var(--accent);margin-bottom:7px}.pillrow{display:flex;gap:8px;flex-wrap:wrap;margin:12px 0}.pill{display:inline-block;font-size:13px;padding:4px 9px;border:1px solid #cfded7;border-radius:5px;text-decoration:none;background:#fff}.pill:hover{background:#e3f0e8}.toc{background:#fff;border:1px solid var(--line);padding:20px 24px;border-radius:9px;margin:24px 0}.toc .toc-title{font-size:13px;font-weight:750;color:var(--muted);margin:0 0 10px}.toc a{display:block;text-decoration:none;font-size:15px;line-height:1.7;padding:4px 0}.toc .sub{padding-left:18px;font-size:14px}.table-wrap{max-width:100%;overflow-x:auto;border:1px solid var(--line);border-radius:8px;margin:21px 0}table{border-collapse:collapse;width:100%;font-size:16px;line-height:1.7;background:#fff}th{background:#eef2ed;text-align:left;font-weight:700}th,td{padding:11px 13px;border-bottom:1px solid var(--line);vertical-align:top}tr:last-child td{border-bottom:0}td{min-width:70px}pre{background:#edf1f2;border:1px solid #d8e0e3;border-radius:8px;overflow-x:auto;padding:20px;font-size:14px;line-height:1.85;max-width:100%;tab-size:4}code{font-family:ui-monospace,SFMono-Regular,Consolas,"Liberation Mono",monospace;font-size:.88em;background:#edf0ed;padding:.1em .3em;border-radius:4px;overflow-wrap:anywhere}pre code{padding:0;background:transparent;font-size:inherit;white-space:pre;overflow-wrap:normal}.term{color:inherit;text-decoration:underline dotted #879b97;text-underline-offset:5px}.source-ref{font-size:12px;margin-left:3px;white-space:nowrap;text-decoration:none;color:#7b8989}.source-note{font-size:14px;color:var(--muted);border-top:1px solid var(--line);padding-top:16px;margin-top:35px}.quiz{background:#fff;border:1px solid var(--line);border-radius:8px;padding:21px 23px;margin:18px 0}.quiz .answer{background:#f4f7f3;border-left:3px solid #9ab9a6;padding:10px 15px;margin:13px 0 0;font-size:16px}.quiz b{font-size:12px;letter-spacing:.06em;color:var(--accent)}.hero{padding:28px 0 10px}.hero h1{font-size:clamp(31px,4vw,47px);max-width:820px;line-height:1.32;margin-bottom:22px}.hero p{max-width:730px}.cta{display:flex;gap:11px;flex-wrap:wrap;margin:26px 0}.button{display:inline-block;padding:10px 17px;background:var(--accent);color:#fff;text-decoration:none;border-radius:7px;font-size:15px;font-weight:650;border:1px solid var(--accent)}.button.secondary{background:#fff;color:var(--accent)}.button:hover{background:#285b59;color:#fff}.metrics{display:grid;grid-template-columns:repeat(4,1fr);gap:1px;border:1px solid var(--line);border-radius:9px;overflow:hidden;margin:24px 0;background:var(--line)}.metric{padding:18px;background:#fff}.metric strong{display:block;font-size:28px;line-height:1.35}.metric span{font-size:12px;color:var(--muted)}.cards{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:16px;margin:25px 0}.card{background:#fff;border:1px solid var(--line);border-radius:9px;padding:21px;min-width:0}.card .num{font-size:12px;color:var(--accent);font-weight:750;letter-spacing:.1em}.card h3{margin:8px 0 12px;font-size:19px}.card p{font-size:14px;color:var(--muted);margin:10px 0}.card a.main-link{color:var(--ink);text-decoration:none}.card a.main-link:hover{color:var(--accent)}.card .path{font-size:13px}.footer{border-top:1px solid var(--line);font-size:12px;color:var(--muted);padding-top:20px;margin-top:50px}.pager{display:flex;justify-content:space-between;gap:14px;flex-wrap:wrap;margin-top:35px;padding-top:20px;border-top:1px solid var(--line)}.pager a{font-size:14px;text-decoration:none}.progress-row{display:flex;gap:14px;align-items:center;margin:18px 0}.progress-row button{font-size:13px}.read-status{font-size:12px;color:var(--muted)}.mobile-menu{display:none}.search-box{display:flex;gap:9px;margin:22px 0}.search-box input{min-width:0;flex:1;border:1px solid #a7c1b8;border-radius:8px;padding:12px 14px;background:#fff}.search-summary{font-size:14px;color:var(--muted)}.search-result{padding:19px 0;border-bottom:1px solid var(--line)}.search-result h3{font-size:19px;margin:0 0 7px}.search-result p{font-size:14px;color:var(--muted);margin:5px 0}.badge{font-size:11px;padding:2px 6px;background:var(--soft);color:var(--accent);border-radius:4px;margin-right:7px}.gloss-item{padding:18px 0;border-top:1px solid var(--line)}.gloss-item h3{margin:4px 0 9px}.gloss-item p{font-size:16px;margin:8px 0}.lab{border:1px solid var(--line);border-radius:10px;background:#fff;padding:24px;margin:25px 0}.lab h2{margin:0 0 15px;border:0;padding:0}.lab-controls{display:flex;gap:12px;flex-wrap:wrap}.lab-controls label{font-size:14px;display:flex;flex-direction:column;gap:4px}.lab-controls input,.lab-controls select{max-width:150px;border:1px solid var(--line);border-radius:6px;padding:6px 9px}.lab-output{background:#edf6f0;padding:14px 18px;border-radius:6px;margin:15px 0;font-size:16px}.lab pre{font-size:15px}.chosen td{background:#e2f0da}.allow{background:#e2f0da;text-align:center}.deny{background:#f4e8e1;color:#7d645b;text-align:center}.error{color:#992d25}.standalone-section{padding-top:50px;margin-top:70px;border-top:3px solid var(--accent)}.edition-note-unused{padding:10px 17px;font-size:13px;background:var(--warm)}body.nav-open .sidebar{display:block}body.nav-open{overflow:hidden}.term-guide{font-size:13px;color:var(--muted);margin:15px 0}mark{background:#f7e2a8;padding:0 2px}
@media(min-width:1500px){:root{--side:285px}.main{padding-left:80px;padding-right:80px}}
@media(max-width:1050px){:root{--side:235px}.top{padding:0 16px;gap:12px}.top nav{gap:13px}.optional{display:none}.main{padding:30px 30px 65px}.sidebar{padding-left:14px;padding-right:12px}.brand{font-size:14px}}
@media(max-width:780px){:root{--font:17px}.top{height:60px;padding:0 12px}.brand{max-width:220px;white-space:normal;line-height:1.4}.top nav{display:none}.tools{margin-left:auto}.mobile-menu{display:inline-block}.layout{display:block}.sidebar{display:none;position:fixed;top:60px;left:0;bottom:0;width:min(88vw,340px);height:calc(100vh - 60px);background:var(--paper);z-index:40;box-shadow:12px 0 35px #0002;padding:22px}.main{padding:25px 18px 65px}.hero{padding-top:10px}.hero h1{font-size:33px}h1{font-size:28px}h2{font-size:23px;margin-top:39px}h3{font-size:20px}.lead{font-size:18px}.panel,.preq,.toc,.lab{padding:17px}.cards{grid-template-columns:1fr;gap:12px}.metrics{grid-template-columns:repeat(2,1fr)}.metric{padding:13px 16px}.metric strong{font-size:24px}table{font-size:14px}th,td{padding:9px 11px}pre{padding:15px;font-size:13px}.quiz{padding:17px}.pill{font-size:12px}.top .tools button{padding:5px 7px}.search-box button{font-size:14px;padding:7px}.pager{gap:20px}.breadcrumb{margin-bottom:20px}html{scroll-padding-top:77px}}
@media print{.top,.sidebar,.pager,.progress-row,.cta,.search-box{display:none}.layout{display:block}.main{padding:0}.article{max-width:none}body{background:#fff;color:#000;font-size:11pt;line-height:1.6}.cards{display:block}.card{break-inside:avoid}.term{text-decoration:none}h1,h2,h3{break-after:avoid}pre,table{font-size:9pt}.table-wrap{overflow:visible}.standalone-section{break-before:page}.source-ref{color:#555}}


.skip-link{position:absolute;top:-60px;left:16px;padding:10px;background:#fff;z-index:100}.skip-link:focus{top:8px}
.book-subtitle{font-size:13px;letter-spacing:.08em;color:var(--muted)}
.route-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:16px;margin:24px 0}
.route-card{padding:21px 23px;border-left:3px solid var(--accent);background:#f1f5f1;border-radius:0 8px 8px 0}
.route-card .num{font-size:12px;font-weight:700;letter-spacing:.12em;color:var(--accent)}
.route-card h3{margin:7px 0 10px;font-size:20px}.route-card p{font-size:15px;margin:9px 0}
.chapter-list{margin:15px 0 27px}.chapter-list>a{display:flex;justify-content:space-between;gap:15px;padding:11px 5px;border-bottom:1px solid var(--line);text-decoration:none;font-size:16px;color:var(--ink)}.chapter-list>a:hover{color:var(--accent)}
.card .path{display:flex;flex-wrap:wrap;gap:13px}.notice,blockquote{background:#f2f6f2;border-left:3px solid #70a397;padding:13px 19px;margin:20px 0;font-size:16px}.notice p,blockquote p{margin:8px 0}.links-row{display:flex;gap:8px;flex-wrap:wrap}
.lecture{padding:20px 0;border-top:1px solid var(--line)}.lecture-title h3{margin:5px 0 14px}.priority{display:inline-block;border:1px solid var(--line);padding:1px 7px;font-size:12px;border-radius:4px;margin-right:8px}.section-divider{margin-top:35px}.source-card{margin:20px 0;border-top:1px solid var(--line);padding-top:15px}.inline-figure svg{max-width:100%;height:auto}.article img{max-width:100%;height:auto}.related{font-size:14px}.end-note{font-size:14px;color:var(--muted)}
.toc .toc-title{margin:0 0 10px}.toc h2{border:0;font-size:16px;margin:0}.toc a{overflow-wrap:anywhere}.article p,.article li,.article td{overflow-wrap:break-word}.article pre{overflow-wrap:normal}.article .badge{font-size:12px}.standalone-section{scroll-margin-top:80px}.standalone-section>h1{font-size:30px}.source-raw{word-break:break-all}
@media(max-width:780px){.route-grid{grid-template-columns:1fr}.top .brand{max-width:185px;font-size:14px}.card .path{gap:14px}.chapter-list>a{font-size:15px}.route-card{padding:18px}.article .lead{font-size:18px}.tools button{min-height:32px}.standalone-section>h1{font-size:25px}}


/* 自检题：答案默认收起，读者主动展开；原生 details 支持键盘与无 JS 阅读。 */
.quiz-answer{margin:14px 0 0;font-size:15px;}
.quiz-answer summary{cursor:pointer;display:list-item;list-style-position:inside;max-width:max-content;padding:7px 13px;border:1px solid #b7d0c6;border-radius:7px;background:#f2f8f5;color:var(--accent);font-weight:650;user-select:none;}
.quiz-answer summary:hover{background:#e6f3ec;}
.quiz-answer summary:focus-visible{outline:3px solid #c38032;outline-offset:3px;}
.quiz-answer .when-open{display:none;}
.quiz-answer[open] .when-open{display:inline;}
.quiz-answer[open] .when-closed{display:none;}
.quiz-answer[open] summary{background:#edf4ee;}
.quiz-answer .answer{margin-top:10px;}
@media print{.quiz-answer:not([open]) .answer{display:none}}

/* Worked examples: input, state transitions and explicit boundaries. */
.worked-example{margin:32px 0;padding:24px 26px;border:1px solid #cbded7;border-left:4px solid #196b6b;border-radius:9px;background:#fff;clear:both;scroll-margin-top:92px}
.worked-label{font-size:12px;letter-spacing:.08em;color:#196b6b;font-weight:750;margin-bottom:8px}
.worked-example h3{font-size:21px;line-height:1.6;margin:6px 0 15px}.worked-example p{font-size:16px;line-height:1.95;margin:14px 0}.worked-setup{background:#f1f7f3;padding:15px 17px;border-radius:6px}
.worked-table{margin:18px 0}.worked-table table{table-layout:fixed;line-height:1.9;font-size:15px}.worked-table th:nth-child(1){width:22%}.worked-table th:nth-child(2){width:35%}.worked-table th:nth-child(3){width:43%}.worked-table td{overflow-wrap:anywhere;word-break:normal}.step-no{display:block;font-size:11px;font-weight:750;color:#196b6b;margin-bottom:3px}.worked-boundary{color:#52666e;background:#f7f7f3;padding:12px 15px;border-radius:6px}.worked-example .worked-citation{font-size:12px;color:#687a7f;line-height:1.9}.worked-related{font-size:14px!important}.worked-takeaway strong{color:#196b6b}
.example-nav{font-size:13px;margin:24px 0;padding:12px 16px;background:#edf5f1;border-radius:7px}.example-index-list{columns:2;column-gap:30px}.example-index-item{break-inside:avoid;display:block;padding:9px 0;font-size:15px}.matrix-block{margin:24px 0}.matrix-block h3{font-size:19px}.matrix-block p{font-size:15px}.matrix-grid{font-variant-numeric:tabular-nums;font-size:14px}.matrix-grid td{text-align:right;white-space:nowrap}.matrix-grid td:first-child{text-align:left}.tensor-caption{font-size:13px;color:#61717a}.validation-scope{background:#fff6e9;border-left:4px solid #b07832;padding:18px 22px;margin:24px 0}.example-code{font-size:13px}
@media(max-width:780px){.worked-example{padding:18px 16px;margin:26px 0}.worked-example h3{font-size:20px}.worked-example p{font-size:16px}.worked-table{border:0;border-radius:0;overflow:visible}.worked-table table,.worked-table tbody,.worked-table tr,.worked-table td{display:block;width:100%;min-width:0}.worked-table thead{display:none}.worked-table tr{border:1px solid #dce4e4;border-radius:7px;margin:13px 0;overflow:hidden}.worked-table td{border-bottom:0;padding:11px 13px}.worked-table td:first-child{background:#edf5f1;font-weight:700}.worked-table td:nth-child(2)::before{content:'内部动作';display:block;font-size:11px;color:#196b6b;font-weight:750}.worked-table td:nth-child(3)::before{content:'结果 / 状态';display:block;font-size:11px;color:#196b6b;font-weight:750}.step-no{display:inline;margin-right:8px}.example-index-list{columns:1}.matrix-grid{font-size:12px}.matrix-grid td{padding:8px}.worked-setup{padding:12px}.matrix-block{max-width:100%}}
@media print{.worked-example{break-inside:auto;background:#fff;padding:12px;border-color:#aaa}.worked-table table{font-size:10pt}.worked-label,.worked-citation{color:#333}.worked-related{display:none}}

/* 对象身份与首次出现说明 */
.concept-note{margin:20px 0;padding:16px 20px;border:1px solid #d8e3dd;border-left:3px solid #4e7970;background:#f4f8f5;border-radius:7px;font-size:15px;line-height:1.85}
.concept-note-label{font-size:12px;letter-spacing:.05em;color:#4d6961;font-weight:700;margin-bottom:9px}
.concept-note dl{margin:0}.concept-note dt{font-weight:700;margin-top:11px}.concept-note dt:first-child{margin-top:0}.concept-note dd{margin:4px 0 0}.concept-note a{text-decoration:none}.concept-micro{display:block;color:#596964;font-size:.95em;margin-top:5px}
.concept-primer{border:1px solid var(--line);border-radius:8px;padding:20px 24px;background:#fff;margin:24px 0}.concept-primer h2,.concept-primer h3{border:0;margin:0 0 12px;padding:0}
.concept-index-links{display:flex;gap:9px;flex-wrap:wrap;font-size:13px;margin:22px 0}.concept-index-links a{display:inline-block;padding:5px 9px;border:1px solid var(--line);border-radius:5px;text-decoration:none;background:#fff}
.concept-entry{padding:18px 0;border-top:1px solid var(--line)}.concept-entry h3{margin:0 0 10px}.qkv-output{white-space:pre-wrap;overflow-wrap:anywhere;line-height:1.75;font-size:14px}.qkv-lab button{align-self:end}.concept-validation{font-size:14px}.concept-note dd code{font-size:.9em}
@media(max-width:780px){.concept-note{padding:13px 14px;font-size:14px}.concept-primer{padding:16px}.qkv-output{font-size:12px}}
@media print{.concept-note,.concept-entry{break-inside:avoid}.qkv-lab .lab-controls{display:none}}