:root{--paper:#f6f5ef;--card:#fffef9;--ink:#243b36;--muted:#62716a;--line:#dce1d7;--green:#286653;--lime:#e5ed9e;--blue:#4169a4;--peach:#f2cbb2;--red:#a44936;--shadow:0 10px 32px #243b3606;--serif:'Songti SC','STSong',Georgia,serif;--sans:-apple-system,BlinkMacSystemFont,'PingFang SC','Microsoft YaHei',sans-serif}*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;background:var(--paper);color:var(--ink);font-family:var(--sans);font-size:16px;line-height:1.75}button,input,select,textarea{font:inherit}button,a,input,textarea,select{-webkit-tap-highlight-color:transparent}button,a{touch-action:manipulation}button{cursor:pointer}a{color:var(--green);text-decoration:none}a:hover{text-decoration:underline}button:focus-visible,a:focus-visible,input:focus-visible,select:focus-visible,textarea:focus-visible,summary:focus-visible{outline:3px solid var(--blue);outline-offset:4px}button{border:0;background:transparent;color:inherit}h1,h2,h3,h4,p{margin-top:0}h1,h2,h3{line-height:1.35}h1{font-family:var(--serif);font-size:44px;letter-spacing:-1px;margin-bottom:20px}h2{font-size:25px}h3{font-size:19px}p{margin-bottom:16px}small,.small{font-size:13px;color:var(--muted)}strong{font-weight:650}ul,ol{padding-left:1.4em}li{margin:8px 0}svg{max-width:100%;height:auto;display:block}input,select,textarea{border:1px solid #bfcabe;border-radius:8px;padding:10px 12px;background:#fffefb;color:var(--ink);max-width:100%}textarea{width:100%;min-height:140px;resize:vertical;line-height:1.75}input[type=range]{accent-color:var(--green);padding:0;width:100%;cursor:pointer}input[type=checkbox],input[type=radio]{accent-color:var(--green);width:18px;height:18px;vertical-align:middle}hr{border:0;border-top:1px solid var(--line);margin:30px 0}.sidebar{width:244px;position:fixed;inset:0 auto 0 0;z-index:20;background:#eeefe6;border-right:1px solid var(--line);overflow:auto;padding:29px 19px 22px}.brand{display:flex;gap:12px;align-items:center;font-size:17px;font-weight:700;line-height:1.45;padding:0 8px 24px}.brand-mark{display:grid;place-items:center;background:var(--green);color:var(--lime);border-radius:12px;width:39px;height:42px;font-family:Georgia;font-size:26px}.brand small{display:block;font-weight:400;font-size:10px;letter-spacing:1.5px;margin-top:4px}.nav-link{display:flex;align-items:center;gap:10px;padding:9px 11px;margin:3px 0;border-radius:8px;font-size:13px;color:#53655b;line-height:1.65}.nav-link:hover{background:#e2e7d9;text-decoration:none}.nav-link.active{background:var(--green);color:#fff}.nav-link .num{font-size:11px;opacity:.7;min-width:19px;font-variant-numeric:tabular-nums}.nav-link .done{margin-left:auto;color:#8cd0a4}.nav-caption{font-size:10px;letter-spacing:1.7px;text-transform:uppercase;color:var(--muted);padding:24px 12px 7px}.sidebar-bottom{padding:20px 10px 0;font-size:12px}.progress-bar{height:5px;background:#dce3d2;border-radius:4px;overflow:hidden;margin:9px 0}.progress-bar>span{display:block;height:100%;background:var(--green);border-radius:4px}.shell{margin-left:244px}.topbar{height:77px;display:flex;justify-content:space-between;align-items:center;border-bottom:1px solid var(--line);padding:0 40px;gap:12px}.crumb{font-size:12px;letter-spacing:1px;color:var(--muted)}.top-actions{display:flex;align-items:center;gap:17px;font-size:12px}.offline{display:flex;align-items:center;gap:6px;white-space:nowrap;color:var(--muted)}.offline i{width:6px;height:6px;border-radius:50%;background:var(--green)}.quiet{padding:5px 0;color:var(--muted);font-size:12px;white-space:nowrap}.quiet:hover{color:var(--green);text-decoration:underline}.file-label{position:relative;cursor:pointer}.file-label input{position:absolute;inset:0;opacity:0;width:100%;cursor:pointer;padding:0}.mobile-only{display:none}main{max-width:1370px;margin:auto;padding:44px 46px 64px;min-height:85vh}.eyebrow{font-size:11px;letter-spacing:2px;font-weight:650;text-transform:uppercase;color:var(--green);margin-bottom:14px}.muted{color:var(--muted)}.hero{display:grid;grid-template-columns:1.1fr 1fr;gap:26px;align-items:center;margin-bottom:40px}.hero h1{font-size:clamp(38px,4.1vw,62px);font-weight:600;line-height:1.3}.hero h1 em{font-style:normal;position:relative;white-space:nowrap}.hero h1 em:after{content:'';position:absolute;left:0;right:0;bottom:3px;height:11px;background:var(--lime);z-index:-1;transform:rotate(-2deg)}.hero .lead{max-width:465px;line-height:1.95;color:var(--muted);font-size:15px}.hero-art{min-width:0;position:relative;border:1px solid var(--line);border-radius:20px;background:#ecefe4;padding:20px 14px 12px;transform:rotate(1.2deg)}.hero-art .art-caption{display:flex;justify-content:space-between;font-size:10px;letter-spacing:1px;padding:0 13px;color:#607060}.hero-meta{display:flex;gap:28px;margin-top:29px;font-size:12px;color:var(--muted)}.hero-meta strong{font-size:21px;color:var(--ink);font-family:Georgia;display:block}.actions{display:flex;flex-wrap:wrap;gap:12px;margin:21px 0}.btn{display:inline-flex;align-items:center;justify-content:center;gap:10px;background:var(--green);color:#fff;border:1px solid var(--green);padding:11px 18px;border-radius:8px;font-size:14px;font-weight:600;line-height:1.5;transition:background .15s,transform .15s}.btn:hover{background:#1c4c3e;text-decoration:none;transform:translateY(-1px)}.btn.secondary{background:transparent;color:var(--green);border-color:#bdcbbd}.btn.secondary:hover{background:#e8eddf}.btn.lime{background:var(--lime);color:var(--ink);border-color:var(--lime)}.btn.tiny{font-size:12px;padding:7px 11px}.section-heading{display:flex;justify-content:space-between;gap:12px;align-items:baseline;margin:33px 0 19px}.section-heading h2{font-size:23px;margin:0}.section-heading a,.section-heading span{font-size:12px;color:var(--muted)}.route-banner{border-block:1px solid var(--line);display:grid;grid-template-columns:1fr auto 1fr;padding:22px 0;gap:28px;align-items:center}.route-banner h3{font-size:16px;margin:4px 0 5px}.route-banner p{font-size:13px;color:var(--muted);margin:0}.route-banner .arrow{color:#9aa992;font-size:23px}.tag{font-size:10px;letter-spacing:1px;padding:4px 7px;background:#e5ebd9;color:var(--green);border-radius:4px;display:inline-block;line-height:1.5}.tag.blue{background:#e4eafa;color:var(--blue)}.tag.peach{background:#f7e8df;color:#8b5232}.course-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:15px}.course-card{background:var(--card);border:1px solid var(--line);border-radius:12px;padding:21px;position:relative;color:var(--ink);transition:transform .16s,border-color .16s;min-height:185px;display:flex;flex-direction:column}.course-card:hover{transform:translateY(-3px);border-color:#88a48b;text-decoration:none}.course-card .card-meta{display:flex;justify-content:space-between;font-size:11px;color:var(--muted);margin-bottom:20px}.course-card h3{font-size:17px;margin-bottom:9px}.course-card p{font-size:12px;line-height:1.8;color:var(--muted);margin:0}.course-card .card-foot{margin-top:auto;padding-top:13px;display:flex;justify-content:space-between;font-size:11px;color:var(--green)}.featured-strip{display:grid;grid-template-columns:repeat(3,1fr);gap:15px}.lab-tile{border:1px solid var(--line);border-radius:12px;padding:21px;background:#e9eee1;color:var(--ink)}.lab-tile:nth-child(2){background:#e6ebf1}.lab-tile:nth-child(3){background:#f3e9dd}.lab-tile h3{font-size:16px;margin:10px 0}.lab-tile p{font-size:12px;color:var(--muted);margin:0}.mini-icon{font-size:24px;font-family:Georgia}.footer{padding:24px 46px;border-top:1px solid var(--line);font-size:11px;color:var(--muted);display:flex;justify-content:space-between;gap:20px}.page-head{max-width:800px;margin-bottom:30px}.page-head p{color:var(--muted);font-size:15px}.page-head h1{font-size:39px}.back-link{display:inline-flex;margin-bottom:22px;font-size:12px}.chapter-layout{display:grid;grid-template-columns:minmax(0,1fr) 235px;gap:36px}.reading{min-width:0}.reading section{margin-bottom:35px}.reading p{line-height:1.95}.reading .lesson-section{padding-bottom:26px;border-bottom:1px solid var(--line)}.reading h2{font-size:23px;margin-top:7px}.reading h3{font-size:18px;margin-top:20px}.reading table,.data-table{border-collapse:collapse;width:100%;font-size:13px;margin:20px 0;background:var(--card)}th,td{text-align:left;border-bottom:1px solid var(--line);padding:12px 13px;vertical-align:top}th{background:#edf0e5;font-weight:600;white-space:nowrap}.reading table{display:block;overflow-x:auto}.reading code{background:#ebeee5;padding:2px 5px;border-radius:4px;font-size:13px;overflow-wrap:anywhere}.chapter-aside{font-size:13px;min-width:0}.sticky{position:sticky;top:24px}.note-box{background:#e9ede1;padding:20px;border-radius:12px;margin-bottom:20px}.note-box h3{font-size:14px;margin-bottom:12px}.note-box ul{padding-left:17px;font-size:12px}.note-box textarea{background:#f9faf3;font-size:12px;min-height:170px}.callout{border-left:3px solid var(--green);background:#edf1e5;padding:21px 23px;border-radius:0 10px 10px 0;margin:23px 0;font-size:14px}.callout.warm{background:#f6ece2;border-color:#c18764}.callout.blue{background:#eaf0f8;border-color:var(--blue)}.callout p:last-child{margin:0}.flow{display:flex;align-items:stretch;gap:8px;flex-wrap:wrap;margin:20px 0}.flow>span,.flow>.node{background:#e8eee0;padding:11px;border-radius:8px;font-size:13px;flex:1;min-width:90px;text-align:center}.diagram-band{border:1px solid var(--line);border-radius:12px;background:var(--card);padding:24px;margin:25px 0}.diagram-band svg text{font-family:var(--sans)}.diagram-label{font-size:11px;letter-spacing:1px;color:var(--muted);margin-bottom:15px}.lab-invite{background:var(--green);color:#fff;padding:25px;border-radius:12px;margin:26px 0;display:flex;gap:24px;align-items:center;justify-content:space-between}.lab-invite h3{margin:0 0 8px}.lab-invite p{font-size:13px;margin:0;color:#d6e6da}.lab-invite .btn{flex-shrink:0}.quiz{border:1px solid var(--line);background:var(--card);border-radius:10px;padding:22px;margin:15px 0}.quiz h3{font-size:16px;margin:0 0 15px}.options{display:grid;gap:8px}.option{border:1px solid var(--line);border-radius:7px;padding:12px 15px;text-align:left;background:#fafbf6;font-size:14px;line-height:1.65}.option:hover{border-color:#789c83}.option.selected{border-color:var(--green);background:#e7eedc}.option.correct{background:#e3eddf;border-color:var(--green)}.option.incorrect{background:#f8e8df;border-color:#b57a60}.feedback{background:#edf1e5;border-radius:8px;padding:14px 18px;margin:15px 0;font-size:14px;line-height:1.8}.feedback.error{background:#f8e9df;color:#824637}.feedback:empty{display:none}.next-chapter{display:flex;justify-content:space-between;gap:15px;flex-wrap:wrap;border-top:1px solid var(--line);padding-top:25px}.lab-page{max-width:1100px;margin:auto}.lab-frame{background:var(--card);border:1px solid var(--line);border-radius:16px;padding:30px;margin-bottom:23px;overflow:hidden}.lab-toolbar{display:flex;justify-content:space-between;align-items:center;gap:16px;flex-wrap:wrap;margin-bottom:20px}.segmented{display:flex;gap:5px;flex-wrap:wrap;background:#eef0e7;padding:5px;border-radius:8px}.segmented button{padding:7px 13px;border-radius:5px;font-size:13px}.segmented .active{background:var(--green);color:#fff}.lab-two{display:grid;grid-template-columns:1fr 1fr;gap:30px}.controls{display:grid;gap:18px}.field label,.controls label{display:flex;justify-content:space-between;gap:10px;font-size:13px;margin-bottom:7px}.controls label strong{font-variant-numeric:tabular-nums}.field{margin:12px 0}.stats{display:grid;grid-template-columns:repeat(3,1fr);gap:12px;margin:22px 0}.stat{background:#edf1e5;border-radius:10px;padding:17px}.stat strong{font-family:Georgia;font-size:30px;display:block;line-height:1.25;font-weight:500}.stat span{font-size:11px;color:var(--muted);display:block;margin-top:8px}.formula{font-family:ui-monospace,SFMono-Regular,monospace;font-size:13px;background:#e8eee2;padding:13px 17px;border-radius:7px;overflow-wrap:anywhere}.sample-label{color:var(--muted);font-size:11px;padding:8px 0}.journey-stage{position:relative;border-top:1px solid var(--line);margin-top:20px;padding-top:22px}.journey-svg{width:100%}.particle{offset-path:path('M 65 65 L 780 65');animation:travel 5s infinite linear}.paused .particle{animation-play-state:paused}.flow-dot{animation:pulse 1.8s infinite}.paused .flow-dot{animation-play-state:paused}@keyframes travel{to{offset-distance:100%}}@keyframes pulse{50%{opacity:.35}}.cover-preview{background:#263d36;border-radius:12px;padding:25px;min-height:240px;position:relative;color:#eff5dd;overflow:hidden}.cover-preview:after{content:'↗';font-family:Georgia;font-size:140px;position:absolute;right:8px;bottom:-50px;opacity:.18}.cover-preview .overline{letter-spacing:2px;font-size:10px;color:#b5c9b4}.cover-preview h2{font-size:36px;font-family:var(--serif);max-width:80%;margin-top:30px}.cover-title{background:#eff1e7;padding:18px;border-radius:0 0 10px 10px;font-weight:600;font-size:16px}.select-stack{display:grid;gap:20px}.select-stack select{width:100%}.scroll-table{overflow:auto;border-radius:10px;margin:15px 0}.data-table{margin:0;min-width:620px}.data-table input{width:105px;padding:6px 8px;font-size:13px}.data-table select{max-width:170px}.row-dirty td{background:#fff1e8}.watch-track{display:grid;grid-template-columns:75px 1fr 65px;gap:15px;align-items:center;font-size:13px;margin:16px 0}.bar-track{height:20px;background:#e9eee1;border-radius:5px;overflow:hidden}.bar-fill{height:100%;background:var(--green);border-radius:5px}.bar-fill.blue{background:var(--blue)}.bar-fill.peach{background:#ba8764}.check-row{display:flex;gap:12px;align-items:flex-start;padding:14px;border-bottom:1px solid var(--line);font-size:14px}.check-row input{flex-shrink:0;margin-top:4px}.timeline{display:grid;grid-template-columns:repeat(4,1fr);gap:10px;margin:22px 0}.timeline-item{padding:16px;border-top:3px solid var(--green);background:#edf1e5;font-size:12px}.timeline-item strong{display:block;font-size:15px;margin-bottom:6px}.search-input{width:100%;margin-bottom:25px;padding:15px 18px;font-size:16px}.glossary-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:17px}.term{background:var(--card);border:1px solid var(--line);padding:23px;border-radius:10px}.term h3{margin:0 0 10px;font-size:18px}.term .en{font-family:Georgia;font-size:12px;color:var(--green);display:block;margin-bottom:12px}.term p{font-size:14px;margin-bottom:10px}.term .example{background:#edf1e5;padding:12px;border-radius:6px;font-size:13px}.interview-layout{display:grid;grid-template-columns:255px minmax(0,1fr);gap:28px}.question-list{max-height:650px;overflow:auto;border:1px solid var(--line);border-radius:10px;padding:8px;background:#f0f2e8}.question-list button{display:block;width:100%;text-align:left;border-radius:6px;padding:11px;font-size:13px}.question-list button.active{background:var(--green);color:#fff}.interview-card{min-width:0}.timer{display:flex;gap:14px;align-items:center;flex-wrap:wrap;background:#e9efdf;border-radius:9px;padding:14px 18px;margin:20px 0}.timer output{font:30px Georgia;min-width:80px}.timer span{font-size:12px;color:var(--muted)}details{background:var(--card);border:1px solid var(--line);border-radius:9px;padding:16px 20px;margin:18px 0}summary{cursor:pointer;font-weight:600;font-size:14px}details[open] summary{margin-bottom:20px}.source{border-bottom:1px solid var(--line);padding:22px 0}.source p{font-size:14px;color:var(--muted);margin:8px 0}.source a{overflow-wrap:anywhere}.source h3{margin-bottom:5px}.report-fields{display:grid;gap:20px}.report-fields textarea{min-height:130px}.empty{padding:50px 25px;text-align:center;background:#edf1e5;border-radius:12px}.storage-warning{background:#fae5ce;padding:12px 30px;font-size:13px}.skip{position:fixed;top:-80px;left:270px;z-index:100;background:var(--green);color:#fff;padding:10px 20px}.skip:focus{top:10px}#toast{position:fixed;bottom:25px;left:calc(50% + 100px);transform:translateX(-50%);padding:12px 23px;background:var(--ink);color:#fff;border-radius:8px;font-size:13px;z-index:100;opacity:0;pointer-events:none;transition:opacity .2s;max-width:85vw}#toast.show{opacity:1}body.reduce-motion *,body.reduce-motion *:before,body.reduce-motion *:after{animation:none!important;transition:none!important;scroll-behavior:auto!important}.nowrap{white-space:nowrap}.chapter-check{background:#e5edda;border-radius:10px;padding:20px;margin-top:30px}.chapter-check p{font-size:13px;margin:0 0 15px}.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}.grid-two{display:grid;grid-template-columns:1fr 1fr;gap:20px}.hint{font-size:13px;color:var(--muted)}.lab-select-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:16px}.comparison-bars{display:grid;gap:10px}.comparison-bars .row{display:grid;grid-template-columns:65px 1fr 70px;align-items:center;gap:12px;font-size:13px}.quote{font-family:var(--serif);font-size:20px;border-left:2px solid var(--green);padding:3px 0 3px 22px;line-height:1.9}.number-badge{display:inline-grid;place-items:center;background:#e3eacb;border-radius:50%;width:29px;height:29px;font-size:12px;margin-right:10px}
@media(prefers-reduced-motion:reduce){*{animation-duration:.01ms!important;animation-iteration-count:1!important;scroll-behavior:auto!important;transition:none!important}}@media(min-width:1550px){main{padding-inline:66px}.hero h1{font-size:65px}.course-card{min-height:205px}}@media(max-width:1200px){.sidebar{width:214px;padding-inline:13px}.shell{margin-left:214px}main{padding:35px 30px}.topbar{padding-inline:30px}.top-actions{gap:12px}.chapter-layout{grid-template-columns:minmax(0,1fr) 205px;gap:23px}.course-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.hero h1{font-size:43px}.hero{gap:15px}.hero-meta{gap:22px}}@media(max-width:980px){.hero{grid-template-columns:1fr}.hero-art{max-width:590px;transform:none}.chapter-layout{grid-template-columns:1fr}.chapter-aside .sticky{position:static;display:grid;grid-template-columns:1fr 1fr;gap:20px}.topbar .crumb{display:none}.topbar{justify-content:flex-end}.interview-layout{grid-template-columns:1fr}.question-list{max-height:220px}.featured-strip{grid-template-columns:1fr}.lab-two{grid-template-columns:1fr}.hero .lead{max-width:none}.glossary-grid{grid-template-columns:1fr}}
@media(max-width:760px){body{font-size:15px}.sidebar{display:none;width:270px;box-shadow:20px 0 40px #0002;top:64px}.sidebar.open{display:block}.shell{margin-left:0}.mobile-only{display:block}.topbar{height:64px;position:sticky;top:0;background:var(--paper);z-index:30;justify-content:space-between;padding:0 18px}.icon-button{font-size:20px;padding:6px 12px}.top-actions{gap:14px}.top-actions .offline{display:none}main{padding:29px 21px 45px}.hero h1{font-size:44px}.hero{gap:24px;margin-bottom:28px}.hero-meta{gap:30px}.course-grid{gap:12px}.course-card{padding:16px;min-height:190px}.course-card h3{font-size:16px}.course-card p{font-size:11px}.hero-art{padding:15px 6px 8px}.route-banner{gap:15px;padding:20px 0}.route-banner h3{font-size:14px}.route-banner .arrow{font-size:18px}.section-heading h2{font-size:21px}.section-heading span{max-width:140px;text-align:right}.chapter-aside .sticky{grid-template-columns:1fr}.page-head h1{font-size:33px}.lab-frame{padding:19px 16px;border-radius:12px}.lab-invite{display:block;padding:21px}.lab-invite .btn{margin-top:18px}.stats{gap:8px}.stat{padding:13px 10px}.stat strong{font-size:24px}.stat span{font-size:10px}.lab-select-grid{grid-template-columns:1fr}.timeline{grid-template-columns:1fr 1fr}.footer{padding:23px;display:block}.footer span{display:block;margin-top:7px}.grid-two{grid-template-columns:1fr}.journey-svg{min-width:580px}.journey-stage{overflow:auto}.watch-track{grid-template-columns:60px 1fr 40px;gap:8px;font-size:12px}.lab-toolbar{gap:10px}.skip{left:20px}#toast{left:50%}.hero-meta strong{font-size:22px}.glossary-grid{grid-template-columns:1fr}}
@media print{.sidebar,.topbar,.footer,.actions,.chapter-aside,#toast,.back-link,.mobile-only,.lab-invite{display:none!important}.shell{margin:0}main{padding:0;max-width:none}.chapter-layout{display:block}body{background:#fff;color:#000;font-size:11pt}.page-head h1{font-size:24pt}.lesson-section,.quiz,.callout{break-inside:avoid}.quiz .options{display:block}.option{display:block;width:100%;margin:5px 0}textarea{min-height:60px}a{color:#000}.course-grid{display:block}.course-card{break-inside:avoid;margin:10px 0}.lab-frame{break-inside:avoid}.hero{display:block}.hero-art{max-width:350px}details>*{display:block!important}}
