/* 慢慢懂: a growing reading shelf, native CSS, green carried over from 模型漫游. */
:root{color-scheme:light;--bg:#f4f6f2;--paper:#fafbf8;--ink:#24382d;--muted:#59685e;--accent:#206346;--soft:#e6eee6;--line:#d1dbd1;--radius:16px;font-family:-apple-system,BlinkMacSystemFont,"PingFang SC","Microsoft YaHei",sans-serif;font-synthesis:none;line-height:1.75;background:var(--bg);color:var(--ink)}
*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:96px}body{margin:0}button,input{font:inherit;color:inherit}button{cursor:pointer}a{color:var(--accent);text-underline-offset:5px}a,button,input,summary{-webkit-tap-highlight-color:transparent}a:focus-visible,button:focus-visible,input:focus-visible,summary:focus-visible{outline:3px solid var(--accent);outline-offset:5px}h1,h2,h3,p{margin:0}h1,h2,h3{line-height:1.35;letter-spacing:-.035em}p{overflow-wrap:anywhere}button{background:transparent;border:0}a{text-decoration-thickness:1px}[hidden]{display:none!important}.skip{position:fixed;z-index:99;top:8px;left:16px;padding:8px 16px;background:var(--paper);transform:translateY(-150%)}.skip:focus{transform:none}.book-header{position:sticky;top:0;z-index:20;max-width:1280px;margin:auto;min-height:78px;display:flex;align-items:center;gap:30px;padding:16px 40px;background:var(--bg);border-bottom:1px solid var(--line)}.book-brand{font-weight:720;font-size:23px;color:var(--ink);text-decoration:none;letter-spacing:-.06em;white-space:nowrap}.book-brand span{font-size:11px;font-weight:450;letter-spacing:.04em;margin-left:16px;color:var(--muted)}.book-header nav{display:flex;gap:24px;margin-left:auto}.book-header nav a{font-size:13px;text-decoration:none;color:var(--muted);white-space:nowrap}.book-header nav a[aria-current]{color:var(--accent);text-decoration:underline;text-underline-offset:9px}.theme-toggle{font-size:12px;border:1px solid var(--line);border-radius:6px;padding:6px 10px;min-height:36px;white-space:nowrap}.book-main{max-width:1160px;padding:0 32px;margin:auto}.book-hero{display:grid;grid-template-columns:1.2fr .8fr;gap:80px;align-items:center;padding:66px 0 76px}.overline{font-size:13px;color:var(--accent);margin-bottom:24px}.book-hero h1{font-size:clamp(36px,4.5vw,59px);font-weight:650;line-height:1.3;letter-spacing:-.065em}.intro{font-size:17px;color:var(--muted);max-width:28em;line-height:1.95;margin:25px 0 28px}.solid-link{display:inline-flex;align-items:center;gap:42px;background:var(--accent);color:#f8faf7;padding:12px 20px;border-radius:6px;text-decoration:none;font-size:14px}.book-cover{align-self:stretch;min-height:350px;background:#dce6d8;border-left:12px solid #c7d5c3;padding:30px 32px 24px;display:flex;flex-direction:column;justify-content:space-between;box-shadow:12px 14px 0 #e8ede4;border-radius:2px 8px 8px 2px;transform:rotate(2deg)}.cover-author{font-size:11px;color:#365440;letter-spacing:.08em}.cover-title{font-size:40px;line-height:1.2;font-weight:650;letter-spacing:-.05em;color:#284831;padding:24px 0}.cover-title>span{display:block;font-size:12px;font-weight:400;margin-top:20px;letter-spacing:.04em}.cover-topics{display:flex;flex-wrap:wrap;gap:12px;padding-top:15px;border-top:1px solid #a7bda4;color:#365440;font-size:10px}.section-heading{margin-bottom:28px}.section-heading h2,.reading-start h2,.book-about h2{font-size:27px;font-weight:620}.section-heading p,.reading-start>div>p{font-size:14px;color:var(--muted);margin-top:12px}.shelf{padding:10px 0 60px}.volume-grid{display:grid;grid-template-columns:1fr 1fr;gap:26px}.volume{background:var(--paper);border:1px solid var(--line);border-radius:10px;overflow:hidden}.volume-art{height:130px;display:flex;justify-content:center;align-items:center;gap:16px;background:#e6ede3;color:#385d40}.volume-art span{display:grid;place-items:center;border:1px solid #9eb59f;padding:8px 16px;border-radius:4px;font-size:16px}.volume-art i{font-style:normal;font-size:19px}.web3-art{background:#e9eae1;color:#4a5943}.web3-art span{border-radius:50%;width:58px;height:58px;border-color:#abb49f;padding:0}.volume-copy{padding:25px 28px 28px}.volume-label{font-size:11px;color:var(--muted);margin-bottom:7px}.volume h3{font-size:25px}.volume h3 a{text-decoration:none;color:var(--ink);display:flex;justify-content:space-between;align-items:center;gap:15px}.volume h3 span{font-size:20px;color:var(--accent)}.volume-copy>p:not(.volume-label){font-size:14px;color:var(--muted);line-height:1.9;margin-top:15px;max-width:29em}.volume-meta{display:flex;flex-wrap:wrap;gap:16px;font-size:11px;color:var(--muted);margin:20px 0 16px}.volume-meta span{color:var(--accent)}.text-link{font-size:13px;font-weight:550;text-decoration:none;display:inline-block;min-height:32px;padding:3px 0}.text-link:hover{text-decoration:underline}.reading-start{display:grid;grid-template-columns:.85fr 1.15fr;gap:65px;padding:45px 0 60px;border-top:1px solid var(--line)}.starter-list{list-style:none;margin:0;padding:0;display:grid;gap:16px}.starter-list a{display:flex;align-items:center;justify-content:space-between;gap:20px;color:var(--ink);text-decoration:none;padding:8px 0;min-height:44px}.starter-list span{font-size:14px}.starter-list small{font-size:11px;white-space:nowrap;color:var(--accent)}.starter-list a:hover span{text-decoration:underline}.book-about{display:grid;grid-template-columns:.85fr 1.15fr;gap:65px;padding:50px 0 70px;border-top:1px solid var(--line)}.about-heading>.text-link{margin-top:22px}.about-copy p{font-size:14px;color:var(--muted);line-height:2;margin-bottom:16px}.about-copy details{font-size:13px;margin-top:24px}.about-copy summary{cursor:pointer;color:var(--accent)}.about-copy details p{margin-top:14px}.book-footer{max-width:1160px;padding:26px 32px 35px;display:flex;justify-content:space-between;gap:25px;margin:auto;border-top:1px solid var(--line)}.book-footer .book-brand{font-size:18px}.book-footer p{color:var(--muted);font-size:11px;margin-top:9px}.book-footer>div:last-child{text-align:right}.book-footer>div:last-child>a,.print-book{font-size:12px;margin-left:20px;color:var(--muted)}.print-book{padding:0;text-decoration:underline;text-underline-offset:4px}.breadcrumb{display:flex;gap:12px;align-items:center;padding:24px 0 0;color:var(--muted);font-size:12px}.breadcrumb a{text-decoration:none}.lesson-page main{max-width:1160px}.lesson-page .hero{padding-top:38px;gap:60px}.lesson-page .hero-copy h1{font-size:clamp(35px,4.3vw,54px)}.lesson-page .hero-description{max-width:28em;font-size:16px}.lesson-page .hero .token-demo{border-radius:12px;background:var(--soft);border-color:var(--line)}.lesson-page .section{padding-top:65px}.lesson-page .chinese-section{padding-top:22px}.lesson-page .section-intro h2{font-size:29px}.lesson-page .section-intro{max-width:720px}.video-shelf{border:1px solid var(--line);border-radius:10px;overflow:hidden;background:var(--paper);margin:26px 0 16px}.voice-video{display:grid;grid-template-columns:32px 1fr auto;gap:18px;padding:23px 26px;align-items:start}.voice-video+.voice-video{border-top:1px solid var(--line)}.video-order{font-size:14px;font-variant-numeric:tabular-nums;color:var(--accent);padding-top:3px}.voice-video h3{font-size:18px;margin:6px 0}.voice-video h3 a{color:var(--ink);text-decoration:none}.voice-video h3 a:hover{text-decoration:underline}.voice-video p:not(.mini){font-size:12px;color:var(--muted)}.video-duration{font-size:12px;color:var(--muted);white-space:nowrap;padding-top:3px}.edition-link{display:block;font-size:12px;margin:8px 0 18px}.lesson-page .resource-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.lesson-page .resource{border-radius:8px;background:var(--paper);border-color:var(--line)}.lesson-page .lab-panel{background:var(--paper);border-color:var(--line);border-radius:10px}.lesson-page .stop-content>p:not(.source-note):not(.meta){max-width:43em;line-height:1.95}.lesson-page .route-map{top:100px}.lesson-page .stop{scroll-margin-top:100px}.lesson-page .source-note{color:var(--muted)}
:root[data-theme="dark"]{color-scheme:dark;--bg:#19231e;--paper:#212e26;--ink:#e0e8dd;--muted:#acbbae;--accent:#9ccba9;--soft:#283a2d;--line:#3c5142}:root[data-theme="dark"] .solid-link,:root[data-theme="dark"] .primary{color:#19231e;background:#9ccba9}:root[data-theme="dark"] .volume-art{background:#2a3c2e;color:#d0dfcd}:root[data-theme="dark"] .web3-art{background:#30392a;color:#d6dfcb}:root[data-theme="dark"] .volume-art span{border-color:#657f65}:root[data-theme="dark"] .book-cover{background:#344a35;border-color:#2c402d;box-shadow:12px 14px 0 #243328}:root[data-theme="dark"] .cover-author,:root[data-theme="dark"] .cover-title,:root[data-theme="dark"] .cover-topics{color:#dfebd5}:root[data-theme="dark"] .lesson-page .sentence>span,:root[data-theme="dark"] .mode-switch,:root[data-theme="dark"] .parameter{background:#212e26;color:#e0e8dd;border-color:#506453}:root[data-theme="dark"] .lesson-page .candidates>div,:root[data-theme="dark"] .quiz-options button{background:#283a2d;color:#e0e8dd;border-color:#506453}:root[data-theme="dark"] .lesson-page .mode-switch button[aria-pressed="true"]{background:#3b5140;color:#e0e8dd}:root[data-theme="dark"] .lesson-page .complete[aria-pressed="true"],:root[data-theme="dark"] .lesson-page .lora-highlight{background:#344a35;color:#dfebd5}:root[data-theme="dark"] .lesson-page .filters button[aria-pressed="true"]{color:#19231e;background:#9ccba9}
@media(max-width:900px){.book-header{padding-inline:24px;gap:18px}.book-brand span{display:none}.book-hero{gap:35px}.book-cover{padding:24px;min-height:330px}.cover-title{font-size:35px}.reading-start,.book-about{gap:30px}.starter-list a{align-items:flex-start;flex-direction:column;gap:3px}.lesson-page .hero{gap:30px}}
@media(max-width:650px){.book-header{min-height:68px;padding:13px 18px;gap:13px}.book-brand{font-size:20px}.book-header nav{gap:13px}.book-header nav a{font-size:11px}.book-header nav a:first-child{display:none}.theme-toggle{font-size:10px;padding:5px 7px;min-height:32px}.book-main{padding-inline:22px}.book-hero{grid-template-columns:1fr;gap:32px;padding:42px 0 48px}.overline{margin-bottom:18px;font-size:11px}.book-hero h1{font-size:41px}.intro{font-size:15px;margin:20px 0 23px}.solid-link{font-size:13px}.book-cover{min-height:0;display:grid;grid-template-columns:1fr auto;padding:22px 25px;transform:rotate(1deg);box-shadow:7px 8px 0 #e8ede4}.cover-author{grid-column:1/-1;font-size:10px}.cover-title{font-size:28px;padding:18px 0}.cover-title>span{margin-top:13px;font-size:11px}.cover-topics{flex-direction:column;justify-content:flex-end;border:0;padding:0 0 20px 12px;gap:8px;font-size:10px}.shelf{padding:20px 0 38px}.section-heading h2,.reading-start h2,.book-about h2{font-size:25px}.section-heading p{font-size:13px}.volume-grid{grid-template-columns:1fr;gap:22px}.volume-art{height:105px}.volume-copy{padding:22px}.volume-copy>p:not(.volume-label){font-size:13px}.volume h3{font-size:23px}.reading-start,.book-about{grid-template-columns:1fr;gap:25px;padding:35px 0 40px}.starter-list{gap:12px}.starter-list a{flex-direction:row;gap:12px;align-items:center}.starter-list span{font-size:13px;max-width:17em}.starter-list small{font-size:10px}.about-copy p{font-size:13px}.book-footer{padding:24px 22px 30px;flex-direction:column}.book-footer>div:last-child{text-align:left}.book-footer>div:last-child>a,.print-book{margin-left:0;margin-right:16px;font-size:11px}.lesson-page .hero-copy h1{font-size:38px}.lesson-page .hero-description{font-size:14px}.lesson-page .hero{padding-top:28px}.lesson-page .section{padding-top:45px}.lesson-page .section-intro h2{font-size:25px}.lesson-page .resource-grid{grid-template-columns:1fr}.voice-video{padding:20px 17px;grid-template-columns:20px 1fr;gap:10px}.voice-video h3{font-size:16px}.video-duration{grid-column:2;padding-top:0;font-size:11px}.voice-video .mini{font-size:11px}.lesson-page .breadcrumb{padding-top:19px}.lesson-page .book-header{max-width:none}}
@media(max-width:360px){.book-header{padding-inline:13px;gap:10px}.book-header nav{gap:10px}.book-header nav a{font-size:10px}.book-brand{font-size:18px}.book-hero h1{font-size:36px}.starter-list a{align-items:flex-start;flex-direction:column;gap:2px}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*,*:before,*:after{animation:none!important;transition:none!important}}
@media print{.book-header,.theme-toggle,.solid-link,.print-book{display:none}.book-hero{padding:20px 0;gap:30px}.book-cover{transform:none;box-shadow:none}.book-main{max-width:none}.volume,.book-about,.reading-start{break-inside:avoid}:root{--bg:#fafbf8;--paper:#fafbf8;--ink:#24382d;--muted:#59685e;--accent:#206346}.book-footer{display:none}}
@media(max-width:650px){.volume-art{gap:10px}.volume-art span{white-space:nowrap;flex-shrink:0;font-size:14px;padding:8px 10px}.web3-art span{padding:0;width:52px;height:52px}}