@font-face{font-family:TextbookSong;src:url('./vendor/fonts/TextbookSong.woff2') format('woff2');font-style:normal;font-weight:400 700;font-display:swap}
body.textbook{--book-ink:#272b2e;--book-muted:#727775;--book-paper:#fffefa;--book-rule:#d1d2cc;background:var(--book-paper);color:var(--book-ink);margin:0;font:17px/1.95 TextbookSong,"Noto Serif SC","STSong","SimSun","Times New Roman",serif;letter-spacing:.012em}body.textbook *{box-sizing:border-box}body.textbook a{color:inherit;text-underline-offset:4px}body.textbook :focus-visible{outline:2px solid #7c795f;outline-offset:5px}body.textbook main{width:auto;max-width:none;margin:0;padding:0}body.textbook h1,body.textbook h2,body.textbook h3{font-family:inherit;color:var(--book-ink);letter-spacing:.025em}body.textbook h1{font-weight:600}body.textbook .book-header{max-width:1280px;min-height:74px;margin:auto;padding:0 32px;display:flex;align-items:center;justify-content:space-between;border-bottom:1px solid var(--book-rule);font-size:12px}.book-brand{display:flex;align-items:center;gap:22px;text-decoration:none;letter-spacing:.15em}.book-brand>span{border-left:1px solid #a9aca7;padding-left:22px;color:#777c79}.book-header nav{display:flex;gap:25px;font-size:11px}.book-header nav a{text-decoration:none;color:#777c79!important}.book-header nav a:hover{color:#2b514f!important}.book-footer{max-width:1280px;margin:70px auto 0;padding:23px 32px;border-top:1px solid var(--book-rule);display:flex;justify-content:space-between;gap:20px;font-size:10px;letter-spacing:.06em;color:#7d827d}.book-footer a{text-decoration:none}.book-home{max-width:930px!important;margin:0 auto!important;padding:70px 42px 0!important}.book-title-page{text-align:center;max-width:760px;margin:auto}.book-title-course{font-size:23px;font-weight:500;letter-spacing:.2em}.book-edition{font-size:11px;color:#82867f;letter-spacing:.2em;margin:12px 0 32px}.book-title-page h1{font-size:56px!important;font-weight:500!important;margin:0;line-height:1.4;letter-spacing:.3em;padding-left:.3em}.book-english-title{font-family:KaTeX_Main,Georgia,serif;font-style:italic;font-size:21px;letter-spacing:.05em;margin:10px 0 30px;color:#5c645f}.book-title-rule{width:65px;height:1px;background:#73776d;margin:25px auto}.book-abstract{text-align:justify;text-indent:2em;font-size:16px;line-height:2;max-width:630px;margin:27px auto;color:#555c57}.book-cover-math{font-size:18px;margin:28px auto}.book-title-meta{font-size:10px;letter-spacing:.16em;color:#868b82;margin:30px 0 0}.book-contents{max-width:720px;margin:65px auto 0}.book-contents h2{text-align:center;font-size:24px;font-weight:500;margin:0 0 30px;letter-spacing:.2em}.book-unit-list{display:grid;gap:0}.book-unit{display:flex;align-items:baseline;gap:16px;text-decoration:none;font-size:16px;padding:9px 0}.book-unit-number{font-family:KaTeX_Main,Georgia,serif;width:20px;text-align:center}.book-unit-title{white-space:nowrap}.book-unit-dots{flex:1;border-bottom:1px dotted #b6bab2;margin:0 4px 6px}.book-unit-time{font-size:11px;color:#777e76;white-space:nowrap}.book-unit:hover{color:#1c656a!important}.book-contents-note{font-size:12px;color:#8a8e85;line-height:1.9;margin-top:25px}.book-cover-plate{margin:55px 0 0}.book-cover-plate #book-hero{min-height:300px;background:#fbfbf8;border-top:1px solid #dfe2d9;border-bottom:1px solid #dfe2d9}.book-cover-plate .home-field{height:320px!important;border:0!important;border-radius:0!important;margin:0!important}.book-cover-plate figcaption,.book-lab-section figcaption{font-size:12px;line-height:1.85;color:#65706a;margin:16px auto 0;max-width:760px;text-align:justify}.book-cover-plate figcaption>b,.book-lab-section figcaption>b{color:#364c45;font-weight:600}.book-practice{max-width:720px;margin:45px auto 0;padding-top:28px;border-top:1px solid var(--book-rule)}.book-practice h2{font-size:18px;font-weight:500;margin:0 0 9px}.book-practice p{font-size:13px;color:#727a71;margin:0}.book-practice-links{display:flex;gap:30px;flex-wrap:wrap;margin-top:18px;font-size:13px}.book-practice-links a{color:#3d6867!important}.book-home-start{max-width:720px;margin:42px auto 0;text-align:right;font-size:13px}.book-home-start a{text-decoration:none;color:#355d5b!important}.book-layout{display:grid;grid-template-columns:165px minmax(0,1fr);gap:50px;max-width:1280px;margin:auto;padding:50px 32px 0}.book-toc{position:sticky;top:30px;align-self:start;font-size:11px;line-height:1.8}.book-toc>p{margin:0 0 20px;padding-bottom:13px;border-bottom:1px solid #d9dcd3;font-size:13px;letter-spacing:.2em;color:#4e6157}.book-toc nav{display:grid;gap:7px}.book-toc nav a{display:flex;gap:10px;padding:6px 0;text-decoration:none;color:#8a8f87!important}.book-toc nav a span{font-family:KaTeX_Main,Georgia,serif;color:#9ca197}.book-toc nav a[aria-current]{color:#2c554e!important;font-weight:600}.book-toc nav a[aria-current] span{color:#2c554e}.book-toc-map{display:block;margin-top:24px;color:#888e83!important;text-decoration:none;font-size:10px}.book-chapter{min-width:0;max-width:990px}.book-chapter-title{max-width:760px;margin:0 auto 40px;text-align:center}.book-kicker{font-size:11px;color:#9a9c93;letter-spacing:.25em}.book-chapter-title h1{font-size:30px!important;line-height:1.7;margin:17px 0 18px;font-weight:600!important}.book-section-number{font:500 29px KaTeX_Main,Georgia,serif;margin-right:20px}.book-chapter-title>p{font-size:14px;color:#858b80;line-height:1.85;margin:0}.book-prose{max-width:760px;margin:0 auto;font-size:16px;line-height:2;text-align:justify;overflow-wrap:anywhere}.book-prose p{margin:0 0 17px;text-indent:2em}.book-prose b{font-weight:600;color:#252f2b}.book-prose em{font-style:normal;font-weight:500}.book-prose h2{font-size:18px!important;font-weight:600;line-height:1.8;margin:35px 0 17px;text-align:left}.book-subnumber{font-family:KaTeX_Main,Georgia,serif;font-size:17px;margin-right:16px}.book-equation{position:relative;background:none!important;border:0!important;padding:8px 48px 10px 16px;margin:22px 0 25px;text-align:center}.book-equation-math{font-size:18px;overflow-x:auto;overflow-y:hidden;padding:8px 0}.book-equation .katex-display{margin:0}.book-equation-number{position:absolute;right:0;top:21px;font:15px KaTeX_Main,Georgia,serif;color:#4e5751}.book-equation>span:not(.book-equation-number){display:block;font-size:11px;line-height:1.8;color:#8b9187;max-width:680px;margin:12px auto 0;text-align:center}.book-prose .katex{font-size:1.04em}.book-example{background:transparent!important;border:0!important;border-top:1px solid #cdd2c6!important;border-bottom:1px solid #e1e3dc!important;border-radius:0!important;padding:18px 0 17px!important;margin:27px 0!important}.book-example>b{display:block;font-size:14px;line-height:1.8;margin-bottom:11px;color:#485545;font-weight:500}.book-example-number{font-weight:600}.book-example p{font-size:15px;margin:0;text-indent:0}.book-prose .book-limit{font-size:12px;color:#8b9186;line-height:1.9;text-indent:0;border-top:1px solid #e0e3db;padding-top:14px;margin-top:26px}.book-lab-section{margin:32px 0 39px;min-width:0}.book-figure-toolbar{display:flex;justify-content:space-between;align-items:center;border-top:1px solid #bac5bb;margin-bottom:0;padding:9px 0;font-size:10px;color:#89958a;letter-spacing:.06em}.book-figure-toolbar a{text-decoration:none;color:#7a8d7e!important}.book-lab{color:#34483e;background:#fbfbf8;padding:0;border:1px solid #d7ded3;border-radius:0;overflow:hidden;min-width:0}.book-lab-section figcaption{max-width:760px;margin-top:17px}.book-lab-section figcaption>span{display:block;color:#889386;font-size:11px;margin-top:5px}.book-loading{padding:60px 20px;text-align:center;color:#7c9282;font-size:13px}.book-related{margin:25px 0;font-size:13px}.book-related p{font-size:13px;color:#7e8d80;text-indent:0}.book-related a{color:#3a6c60!important}.book-reference{font-size:11px!important;color:#92978c;text-indent:0!important;margin-top:28px!important}.book-reference a{color:#677c69!important}.book-pagination{margin:50px auto 0;max-width:760px;display:flex;justify-content:space-between;border-top:1px solid #d8ddd1;padding-top:24px;gap:25px;font-size:12px}.book-pagination a{text-decoration:none;color:#5f7564!important}.book-pagination a:last-child{text-align:right}.book-table-wrap{overflow-x:auto;margin:25px 0}.book-table{border-collapse:collapse;width:100%;font-size:13px;line-height:1.85;text-align:left;min-width:600px;border-top:1.5px solid #737d6e;border-bottom:1.5px solid #737d6e}.book-table caption{caption-side:top;text-align:center;padding:0 0 15px;font-size:13px;color:#52634f}.book-table th{font-weight:600;color:#415441;background:none;padding:12px 14px;border-bottom:1px solid #a1ad99;white-space:nowrap}.book-table td{padding:14px;border-bottom:1px solid #e3e7dd;vertical-align:top;color:#64725e}.book-table tr:last-child td{border-bottom:0}.book-table td a{color:#487064!important}.book-syllabus{max-width:1010px!important;margin:50px auto 0!important;padding:0 32px!important}.book-syllabus .book-prose{margin:0 auto}.book-syllabus .book-table-wrap{margin:35px 0 45px}.book-syllabus .book-prose h2{font-size:18px}.book-prose li{margin-bottom:10px}
@media(max-width:1100px){.book-layout{grid-template-columns:140px minmax(0,1fr);gap:30px;padding:40px 25px 0}.book-toc{font-size:10px}.book-chapter-title h1{font-size:27px!important}.book-prose{font-size:15px}.book-equation-math{font-size:17px}.book-header{padding:0 25px!important}}
@media(max-width:800px){body.textbook{font-size:15px}body.textbook .book-header{min-height:64px;padding:0 19px;font-size:11px}.book-brand{gap:12px;letter-spacing:.07em}.book-brand>span{padding-left:12px}.book-header nav{gap:14px;font-size:10px}.book-header nav a:last-child{display:none}.book-home{padding:40px 24px 0!important}.book-title-course{font-size:19px}.book-edition{margin:9px 0 25px}.book-title-page h1{font-size:43px!important}.book-english-title{font-size:18px}.book-abstract{font-size:14px}.book-cover-math{font-size:16px}.book-contents{margin-top:45px}.book-contents h2{font-size:22px}.book-unit{font-size:14px;gap:12px}.book-unit-time{font-size:10px}.book-cover-plate{margin-top:35px}.book-cover-plate .home-field{height:280px!important}.book-layout{display:block;padding:22px 20px 0}.book-toc{position:static;margin:0 0 28px}.book-toc>p,.book-toc-map{display:none}.book-toc nav{display:flex;overflow-x:auto;gap:14px;border-bottom:1px solid #d8dfd2;padding-bottom:11px}.book-toc nav a{white-space:nowrap;font-size:10px;padding:3px 0}.book-toc nav a span{margin-right:0}.book-chapter-title{margin-bottom:30px}.book-chapter-title h1{font-size:25px!important;margin:13px 0}.book-section-number{font-size:24px;margin-right:13px}.book-chapter-title>p{font-size:12px}.book-prose{font-size:15px;line-height:2.05}.book-prose h2{font-size:17px!important;margin:29px 0 15px}.book-subnumber{font-size:16px;margin-right:12px}.book-equation{padding:8px 25px 8px 0;margin:18px 0 24px}.book-equation-math{font-size:15px}.book-equation-number{font-size:12px;right:-2px;top:20px}.book-equation>span:not(.book-equation-number){font-size:10px;line-height:1.8}.book-lab-section{margin-left:-6px;margin-right:-6px}.book-figure-toolbar{font-size:9px}.book-lab-section figcaption{padding:0 6px;font-size:11px}.book-lab-section figcaption>span{font-size:10px}.book-example p{font-size:14px}.book-example>b{font-size:13px}.book-prose .book-limit{font-size:11px}.book-footer{padding:21px 20px;margin-top:45px;flex-direction:column;gap:7px;font-size:9px}.book-syllabus{padding:0 20px!important;margin-top:35px!important}.book-pagination{font-size:11px}.book-practice-links{gap:20px;font-size:12px}.book-cover-plate figcaption{font-size:11px}.book-cover-plate #book-hero{min-height:280px}}
@media print{body.textbook{background:white;color:black;font-size:11pt}.book-header,.book-toc,.book-pagination,.book-figure-toolbar,.book-footer,.book-practice-links,.home-field-actions{display:none!important}.book-layout{display:block;padding:0}.book-chapter,.book-prose{max-width:none}.book-lab-section{break-inside:avoid}.book-lab canvas{max-height:360px}.book-title-page{padding-top:80px}.book-equation{break-inside:avoid}a{text-decoration:none}}
.book-prose>span[data-tex],.book-deeper>span[data-tex],.book-example>span[data-tex]{display:block;text-align:center;padding:15px 0;overflow-x:auto;overflow-y:hidden;font-size:.94em}
.book-deeper{margin:24px 0;padding:15px 20px;border-top:1px solid #d4d9cf;border-bottom:1px solid #d4d9cf;font-size:14px}.book-deeper summary{cursor:pointer;color:#345c53;font-size:14px;text-align:left}.book-deeper p:first-of-type{margin-top:15px}

.book-current{max-width:720px;margin:38px auto 0;padding:22px 0;border-top:2px solid #355d5b;border-bottom:1px solid #d1d2cc}.book-current-kicker{font:12px/1.6 system-ui,sans-serif;color:#355d5b;letter-spacing:.06em}.book-current h2{font-size:21px!important;margin:8px 0}.book-current p{font-size:13px;line-height:1.8;color:#65706a}.book-current-links{display:flex;flex-wrap:wrap;gap:12px 26px;margin-top:18px}.book-current a{font-size:14px;color:#355d5b!important}.book-chapter-current{margin:0 auto 35px}