:root{font-family:"Segoe UI","Microsoft YaHei",sans-serif;color-scheme:light;--bg:#f5f5ef;--card:#fffefa;--ink:#243b33;--muted:#69766e;--line:#dce2d7;--green:#235c45;--soft:#e8eee3;--gold:#d8ae66}*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--ink);line-height:1.7;font-size:16px}body.dark{color-scheme:dark;--bg:#16251f;--card:#20352b;--ink:#edf1e7;--muted:#b1c0b3;--line:#3b5042;--green:#a5d9b6;--soft:#2a4234}a{color:inherit;text-decoration:none}button,input{font:inherit}button,.button{display:inline-flex;justify-content:center;align-items:center;min-height:46px;padding:10px 17px;border-radius:10px;border:1px solid var(--line);background:var(--card);color:var(--ink);cursor:pointer;font-size:14px;font-weight:600}button:hover,.button:hover{border-color:var(--green)}button:disabled{cursor:wait;opacity:.65}button:focus-visible,a:focus-visible,input:focus-visible{outline:3px solid #a3b666;outline-offset:4px}button.primary,a.primary{background:var(--green);color:var(--bg);border:1px solid transparent;display:inline-flex;align-items:center;justify-content:space-between;gap:28px;min-height:48px;padding:12px 22px;border-radius:10px;font-weight:650;font-size:14px}.app-header{max-width:1120px;margin:auto;display:flex;justify-content:space-between;align-items:center;padding:26px 36px;border-bottom:1px solid var(--line)}.brand{display:flex;align-items:center;gap:11px;font-size:16px;font-weight:700;line-height:1.5}.brand small{display:block;font-size:9px;font-weight:500;letter-spacing:2px;color:var(--muted)}.icon-button{width:46px;padding:8px;background:transparent;font-size:22px}main{max-width:1048px;margin:auto;padding:0 36px 34px}.page-intro{display:flex;justify-content:space-between;align-items:center;padding:58px 0 32px}.eyebrow{font-size:10px;letter-spacing:2.6px;color:var(--green);font-weight:650;margin:0 0 16px}h1{font-size:46px;line-height:1.3;font-weight:650;letter-spacing:-1.4px;margin:0}h2,h3,p{margin-top:0}.lede{color:var(--muted);font-size:15px;margin:19px 0 0}.intro-mark{display:flex;gap:9px;transform:rotate(-7deg);padding:15px 25px;opacity:.9}.intro-mark span{border:1px solid var(--line);background:var(--card);border-radius:15px;width:74px;height:104px;display:grid;place-items:center;font-size:32px;box-shadow:6px 8px 0 var(--soft)}.intro-mark span+span{transform:translateY(22px);background:var(--soft)}.connection-line{display:flex;align-items:center;gap:9px;color:var(--muted);font-size:12px;min-height:44px;margin-bottom:22px;flex-wrap:wrap}.status-dot{width:7px;height:7px;border-radius:100%;background:#9ca79b;flex-shrink:0}body.offline-ready .status-dot{background:#47865c}.connection-line button{padding:3px 8px;min-height:36px;font-size:12px;background:none;border-color:transparent;margin-left:auto;color:var(--green)}.continue-card{border-radius:18px;background:var(--soft);border:1px solid var(--line);padding:28px 30px;display:flex;align-items:center;justify-content:space-between;gap:25px;margin-bottom:42px;position:relative;overflow:hidden}.small-label{font-size:11px;letter-spacing:1.2px;color:var(--green);font-weight:700}.continue-card h2{font-size:23px;line-height:1.5;margin:8px 0 8px}.continue-card p{font-size:13px;color:var(--muted);margin:0;max-width:540px}.continue-card a{white-space:nowrap;flex-shrink:0}.section-heading{display:flex;align-items:center;justify-content:space-between;gap:20px;margin:25px 0 18px}.section-heading h2{font-size:20px;margin:0;font-weight:650}.section-heading h2 span{font-size:12px;background:var(--soft);border-radius:6px;padding:3px 7px;margin-left:8px;vertical-align:middle}.section-heading>span{font-size:12px;color:var(--muted)}.search-box{display:flex;align-items:center;gap:13px;background:var(--card);border:1px solid var(--line);border-radius:10px;padding:10px 15px;margin-bottom:23px}.search-box>span{font-size:25px;line-height:1;color:var(--muted)}.search-box input{border:0;outline:none;width:100%;min-width:0;background:none;color:var(--ink);font-size:14px;height:30px}.search-box kbd{border:1px solid var(--line);border-radius:4px;padding:0 7px;font-size:12px;color:var(--muted)}.book-grid{display:grid;grid-template-columns:1fr 1fr;gap:22px}.book-card{border:1px solid var(--line);border-radius:14px;overflow:hidden;background:var(--card)}.book-cover{display:flex;align-items:center;justify-content:space-between;gap:16px;padding:26px 26px;background:#203e35;color:#f2efe0;min-height:148px;position:relative;overflow:hidden}.book-cover:after{content:"";position:absolute;width:190px;height:190px;border:1px solid #8caa7e40;transform:rotate(40deg);right:-40px;top:-10px;border-radius:24px}.book-cover strong{font-family:Georgia,serif;font-size:56px;line-height:1;font-weight:500;z-index:1}.book-cover span{font:10px/1.8 Consolas,monospace;letter-spacing:1.6px;text-align:right;z-index:1;color:#c2d2b7}.book-content{padding:23px 25px}.category{font-size:11px;color:var(--muted)}.book-content h3{font-size:21px;margin:8px 0 10px;line-height:1.5}.book-content>p{font-size:13px;color:var(--muted);margin-bottom:17px}.tags{display:flex;flex-wrap:wrap;gap:6px;margin-bottom:20px}.tag{font-size:10px;background:var(--soft);padding:3px 8px;border-radius:5px;color:var(--green)}.book-stats{display:flex;gap:20px;font-size:12px;color:var(--muted);padding-top:15px;border-top:1px solid var(--line)}.book-actions{display:flex;align-items:center;justify-content:space-between;gap:10px;margin-top:17px}.book-actions a{min-height:44px;display:flex;align-items:center;font-size:13px;color:var(--green);font-weight:650}.book-actions a:last-child{font-weight:400;font-size:12px}.quiet-note{display:flex;align-items:flex-start;gap:12px;color:var(--muted);font-size:12px;padding:25px 0}.quiet-note>span{font-size:23px;line-height:1.4}.quiet-note p{margin:0;max-width:650px}.page-footer{max-width:976px;margin:0 auto 115px;display:flex;justify-content:space-between;gap:12px;border-top:1px solid var(--line);padding:20px 0;color:var(--muted);font-size:11px}.bottom-nav{position:fixed;bottom:0;left:0;right:0;display:flex;justify-content:center;gap:60px;padding:9px 24px calc(9px + env(safe-area-inset-bottom));background:var(--card);border-top:1px solid var(--line);z-index:20}.bottom-nav a{display:flex;flex-direction:column;align-items:center;justify-content:center;gap:1px;font-size:11px;color:var(--muted);min-width:70px;min-height:48px;border-radius:8px}.bottom-nav a>span{font-size:22px;line-height:1.2}.bottom-nav a[aria-current]{color:var(--green);background:var(--soft);font-weight:700}.compact{padding-bottom:28px}.compact h1{font-size:36px}.record-stats{display:grid;grid-template-columns:repeat(3,1fr);gap:14px;margin-bottom:32px}.stat{background:var(--card);border:1px solid var(--line);border-radius:12px;padding:24px}.stat strong{display:block;font-size:32px;font-weight:550;line-height:1.4}.stat span{font-size:12px;color:var(--muted)}.reading-row,.note-row{background:var(--card);border:1px solid var(--line);border-radius:12px;padding:22px;display:block;margin-bottom:12px;overflow-wrap:anywhere}.reading-row strong,.note-row strong{display:block;font-size:16px;margin-bottom:6px}.reading-row p,.note-row p{font-size:13px;color:var(--muted);margin:0;white-space:pre-wrap}.note-row small{display:block;color:var(--green);font-size:11px;margin-bottom:8px}.info-panel{background:var(--soft);border:1px solid var(--line);border-radius:12px;padding:25px;margin:25px 0}.info-panel h3{font-size:17px;margin-bottom:10px}.info-panel p,.info-panel li{font-size:13px;color:var(--muted)}.info-panel li{margin-bottom:9px}.info-panel ol{padding-left:20px;margin-bottom:0}.button-row{display:flex;flex-wrap:wrap;gap:10px}.empty-state{border:1px dashed var(--line);border-radius:12px;text-align:center;padding:35px 20px;color:var(--muted);font-size:13px}.empty-state h3{font-size:16px;color:var(--ink)}.settings-grid{display:grid;grid-template-columns:1fr 1fr;gap:18px}.setting-card{background:var(--card);border:1px solid var(--line);border-radius:13px;padding:25px}.setting-number{font:12px Consolas,monospace;color:var(--green)}.setting-card h2{font-size:20px;margin:10px 0}.setting-card p{font-size:13px;color:var(--muted)}.caption{font-size:11px!important;color:var(--muted);margin-top:15px;margin-bottom:0}.sr-only{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0,0,0,0)}.skip-link{position:fixed;top:-100px;left:10px;z-index:200;background:var(--card);padding:10px}.skip-link:focus{top:10px}[hidden]{display:none!important}
@media(max-width:650px){.app-header{padding:17px 20px}main{padding:0 20px 24px}.page-intro{padding:35px 0 20px;gap:10px}h1{font-size:34px;letter-spacing:-.7px}.lede{font-size:13px;max-width:220px;margin-top:15px}.eyebrow{font-size:9px;letter-spacing:1.7px;margin-bottom:14px}.intro-mark{padding:0 6px 0 0;gap:5px}.intro-mark span{width:38px;height:64px;font-size:23px;border-radius:8px}.intro-mark span+span{transform:translateY(12px)}.connection-line{font-size:11px;margin-bottom:16px;gap:6px}.connection-line button{font-size:11px;padding:3px 5px}.continue-card{padding:22px;display:block;margin-bottom:28px;border-radius:14px}.continue-card h2{font-size:20px}.continue-card p{font-size:12px}.continue-card a{margin-top:18px;padding:10px 16px;min-height:44px;font-size:13px}.section-heading{margin-top:23px;margin-bottom:15px;gap:8px}.section-heading h2{font-size:18px}.section-heading>span{font-size:10px;max-width:50%;text-align:right}.book-grid{grid-template-columns:1fr;gap:18px}.book-cover{min-height:135px;padding:25px}.book-cover strong{font-size:52px}.book-content{padding:22px}.book-content h3{font-size:21px}.book-stats{gap:18px;font-size:11px}.page-footer{margin:0 20px 100px;font-size:10px;padding:16px 0}.bottom-nav{gap:0;justify-content:space-around;padding-left:15px;padding-right:15px}.bottom-nav a{min-width:76px}.compact h1{font-size:30px}.record-stats{gap:8px}.stat{padding:18px 12px}.stat strong{font-size:27px}.stat span{font-size:11px}.settings-grid{grid-template-columns:1fr}.setting-card{padding:23px}.info-panel{padding:21px}.quiet-note{font-size:11px}.brand{font-size:15px}.brand small{font-size:8px}}
@media(prefers-reduced-motion:no-preference){a,button{transition:background .15s,border-color .15s}}
.topic-search-results{display:grid;grid-template-columns:1fr 1fr;gap:10px;margin:16px 0 28px;max-height:450px;overflow:auto}.topic-search-results a{display:block;padding:14px 16px;border:1px solid var(--line);border-radius:10px;background:var(--card)}.topic-search-results span{display:block;font-size:11px;color:var(--muted)}.topic-search-results strong{font-size:14px}.route-card{padding:28px;border:1px solid var(--line);border-radius:14px;background:var(--card);margin-bottom:22px}.route-card h2{font-size:23px;margin-bottom:12px}.route-card p{font-size:14px;color:var(--muted)}.route-card ol{margin:18px 0 0;padding-left:26px}.route-card li{padding-left:5px;color:var(--green)}.route-card a{display:flex;align-items:center;justify-content:space-between;gap:12px;min-height:48px;border-bottom:1px solid var(--line);font-size:14px}.route-card li:last-child a{border:0}.book-card[data-book="algorithms"] .book-cover{background:#485341}.book-card[data-book="engineering"] .book-cover{background:#3c4a56}.book-card[data-book="advanced"] .book-cover{background:#584e43}.bottom-nav a{min-width:62px}#backup-preview{max-height:85dvh;overflow:auto}#backup-preview p{font-size:14px}#search-status{margin:0 0 18px}.book-stats{flex-wrap:wrap;gap:7px 16px}
@media(max-width:650px){.topic-search-results{grid-template-columns:1fr}.route-card{padding:22px}.route-card h2{font-size:21px}.bottom-nav{padding-left:8px;padding-right:8px}.bottom-nav a{min-width:60px;flex:1;max-width:100px}}