:root{font-family:-apple-system,BlinkMacSystemFont,PingFang SC,Microsoft YaHei,sans-serif;color:var(--ink);background:var(--paper);--paper:#EBEEE8;--surface:#F7F8F4;--ink:#45465E;--muted:#626475;--accent:#007175;--on-accent:#FFFFFF;--ornament:#9B8EA9;--line:#CDD3CD;--control:#7B8181;--soft:#D5EBE1;--error:#9E2A22;--serif:"Songti SC","Noto Serif CJK SC",STSong,serif;--reading-size:26px;font-synthesis:none;color-scheme:light}:root[data-theme=dark]{--paper:#2C2F3B;--surface:#363947;--ink:#EBEEE8;--muted:#BEC2B3;--accent:#B1D5C8;--on-accent:#2C2F3B;--ornament:#D3CCD6;--line:#505365;--control:#83899C;--soft:#45465E;--error:#F091A0;color-scheme:dark}@media(prefers-color-scheme:dark){:root[data-theme=system]{--paper:#2C2F3B;--surface:#363947;--ink:#EBEEE8;--muted:#BEC2B3;--accent:#B1D5C8;--on-accent:#2C2F3B;--ornament:#D3CCD6;--line:#505365;--control:#83899C;--soft:#45465E;--error:#F091A0;color-scheme:dark}}:root[data-size="0"]{--reading-size:22px}:root[data-size="2"]{--reading-size:30px}*{box-sizing:border-box}body{margin:0;min-width:320px}a{color:var(--accent);text-underline-offset:4px}button,input,select,textarea{font:inherit;color:inherit}button,select,.button,.file-button{min-height:44px;cursor:pointer;border:1px solid var(--line);border-radius:6px;padding:10px 16px;background:transparent;color:var(--ink)}button:disabled{opacity:.55;cursor:not-allowed}button:hover:not(:disabled),.button:hover{background:var(--soft)}button.primary,.button.primary{background:var(--accent);color:var(--on-accent);border-color:var(--accent)}button.primary:hover{filter:brightness(1.1)}button[aria-pressed=true]{background:var(--soft);border-color:var(--accent)}a,button,input,select,textarea{touch-action:manipulation}a:focus-visible,button:focus-visible,input:focus-visible,select:focus-visible,textarea:focus-visible{outline:3px solid var(--accent);outline-offset:3px}h1,h2,h3{font-weight:500;line-height:1.35}h1{font-family:var(--serif);font-size:40px;margin:0 0 24px}h2{font-size:25px;margin:0 0 18px}h3{font-size:20px}p{line-height:1.75}small,.muted{color:var(--muted);font-size:14px;line-height:1.65}input:not([type=checkbox]):not([type=radio]),textarea{background:var(--surface);border:1px solid var(--line);border-radius:6px;padding:12px;width:100%;min-width:0}textarea{min-height:150px;line-height:1.7;resize:vertical}label{display:grid;gap:8px}select{max-width:100%}.checkbox{display:flex;align-items:center;gap:10px;min-height:44px}.checkbox input{width:20px;height:20px}main{outline:none;min-height:65vh}.page{max-width:1120px;width:calc(100% - 64px);margin:0 auto;padding:48px 0 64px}.narrow{max-width:720px}.site-header{max-width:1320px;margin:0 auto;padding:24px 32px;display:flex;align-items:center;gap:32px;border-bottom:1px solid var(--line)}.brand{display:flex;align-items:center;gap:10px;text-decoration:none;color:var(--ink);font-family:var(--serif);font-size:25px;white-space:nowrap}.brand-mark{border:1px solid var(--accent);padding:1px 5px}.site-header nav{display:flex;gap:24px;margin-left:auto;align-items:center;flex-wrap:wrap}.site-header nav a{padding:10px 0;text-decoration:none;color:var(--muted)}.site-header nav a[aria-current=page]{color:var(--accent);border-bottom:2px solid}.site-footer{max-width:1120px;margin:0 auto;padding:24px 32px;border-top:1px solid var(--line);display:flex;justify-content:space-between;gap:24px;flex-wrap:wrap;font-size:14px}.actions{display:flex;align-items:center;gap:12px;flex-wrap:wrap;margin:16px 0}.button{display:inline-flex;align-items:center;text-decoration:none}.notice{padding:16px 20px;border-left:3px solid var(--accent);background:var(--soft);line-height:1.7;margin:16px 0}.save-status{font-size:14px;color:var(--muted);line-height:1.65}.save-status button{margin:4px}.save-status.notice{color:var(--ink);max-width:1120px;margin:16px auto}.save-status details{overflow-wrap:anywhere}.skip{position:absolute;left:-10000px}.skip:focus{left:20px;top:10px;padding:16px;background:var(--surface);z-index:100}dialog{color:var(--ink);background:var(--paper);border:1px solid var(--line);border-radius:10px;width:min(650px,calc(100% - 24px));max-height:90dvh;overflow:auto;padding:24px}dialog::backdrop{background:#14231d88}.dialog-title{display:flex;justify-content:space-between;gap:16px;align-items:start;margin-bottom:24px}.dialog-title h2{margin:0}.dialog-title button{font-size:24px;padding:3px 14px}.settings-grid{display:grid;grid-template-columns:1fr 1fr;gap:20px}.settings-grid p,.settings-grid .checkbox{grid-column:1/-1}.original{font-family:var(--serif);font-size:var(--reading-size);line-height:2;overflow-wrap:anywhere;letter-spacing:.035em}:root[data-font=sans] .original{font-family:inherit}ruby{ruby-align:center}rt{font:14px/1.4 -apple-system,sans-serif;letter-spacing:0;color:var(--muted)}.original:has(ruby){line-height:2.6}.backup-panel{border-top:1px solid var(--line);margin-top:40px;padding-top:28px}.file-button input{max-width:230px}.share-preview{background:#ebeee8;color:#45465e;border:1px solid #CDD3CD;padding:30px;margin:24px 0;overflow-wrap:anywhere}.share-preview p{font:26px/1.9 var(--serif);white-space:pre-wrap}.share-preview small,.share-preview a{display:block;color:#007175}.sr-only{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0,0,0,0)}[role=alert]{color:var(--error)}.empty{padding:40px 0}.record{padding:24px 0;border-bottom:1px solid var(--line);overflow-wrap:anywhere}.record pre,.record .note-copy{white-space:pre-wrap;font:inherit;line-height:1.7}.record blockquote{margin:0 0 16px;padding-left:20px;border-left:2px solid var(--line);font:21px/1.8 var(--serif)}.status-tag{font-size:14px;color:var(--muted)}@media(max-width:760px){.site-header{padding:20px;gap:16px;flex-wrap:wrap}.site-header nav{width:100%;justify-content:space-between;margin:0;gap:8px;font-size:15px}.brand{font-size:23px}.page{width:calc(100% - 40px);padding:32px 0 48px}h1{font-size:32px}.site-footer{padding:24px 20px}.original{font-size:var(--reading-size)}.settings-grid{gap:16px}.actions{gap:8px}dialog{padding:20px}.save-status.notice{margin:12px 20px}.file-button,.file-button input{max-width:100%}}@media(prefers-reduced-motion:reduce){*,*:before,*:after{animation:none!important;transition:none!important;scroll-behavior:auto!important}}button,select,.button,.file-button,input:not([type=checkbox]):not([type=radio]),textarea{border-color:var(--control)}.butterfly-mark{display:block;color:var(--accent);flex-shrink:0}.home-butterfly{display:block;width:112px;height:84px;position:relative}.home-butterfly>svg,.home-butterfly>canvas{position:absolute;inset:0;width:112px;height:84px}.home-butterfly[data-renderer=webgl]>svg{visibility:hidden}.home-logo{display:block;width:112px;height:84px;margin:0 auto 24px}.theme-toggle{display:grid;place-items:center;min-width:44px;width:44px;padding:8px;border:0;color:var(--ink);margin-left:4px}.site-header .brand-mark{display:none}.site-header nav{gap:24px}.site-header nav a{text-decoration:none}.site-header nav a:hover{text-decoration:underline}.site-header .brand{gap:12px}.site-header .brand:focus-visible{outline-offset:7px}:root{--size-scale:1}:root[data-size="0"]{--size-scale:.84615385}:root[data-size="2"]{--size-scale:1.15384615}@media(max-width:760px){.site-header{position:relative;padding:20px}.site-header .theme-toggle{position:absolute;right:14px;top:15px}.site-header .brand{padding-right:40px}.site-header nav{gap:8px}.site-header .butterfly-mark{width:40px;height:32px}}.share-dialog{width:min(960px,calc(100% - 32px))}.share-layout{display:grid;grid-template-columns:minmax(0,1.5fr) minmax(240px,1fr);gap:24px}.share-image{min-width:0}.share-image img{display:block;width:100%;height:auto}.share-controls{display:grid;gap:16px;align-content:start}.share-controls textarea{min-height:0;height:5em;max-height:9em;resize:vertical;overflow:auto;line-height:1.7}.share-controls p{margin:0}.share-image>p{text-align:center}@media(max-width:760px){.share-dialog{width:calc(100% - 16px);padding:16px}.share-layout{grid-template-columns:1fr}.share-controls{order:2}}.passage-actions{display:flex;flex-wrap:wrap;gap:8px;margin:24px 0}.passage-actions button{display:inline-flex;align-items:center;gap:8px;min-height:44px}.passage-actions svg{width:18px;height:18px}.reader-toolbar .passage-actions{margin:0}@media(max-width:760px){.passage-actions button{padding:10px 14px}}:root{--learning-han:"LXGW WenKai GB Screen","Kaiti SC","STKaiti",serif}body{font-size:18px}.brand{font-size:24px}.site-header nav{font-size:16px}.learning-han,.learning-home [lang^=zh],.lesson-page .original,.record blockquote[lang^=zh],:root[data-font=sans] .lesson-page .original{font-family:var(--learning-han);font-weight:400}.lesson-page .original rt{font-family:-apple-system,BlinkMacSystemFont,sans-serif}.learning-opening{max-width:720px;margin:auto;text-align:center;padding:64px 0 72px}.learning-opening h1{font:52px/1.35 Georgia,serif;margin:0 0 24px}.home-description{max-width:500px;margin:0 auto 28px;line-height:1.8}.learning-opening>.primary{padding:12px 28px}.preparing{max-width:460px;margin:0 auto 24px;font-size:16px;color:var(--muted)}.draft-label{font-size:14px;color:var(--muted);padding:10px 0;line-height:1.65}.start-guide{max-width:680px;margin:0 auto 48px;border-top:1px solid var(--line);border-bottom:1px solid var(--line);padding:20px 0}.start-guide summary{cursor:pointer;color:var(--accent);text-decoration:underline;text-underline-offset:4px}.start-guide li{padding:10px 0;line-height:1.8}.home-units{max-width:900px;margin:auto}.unit-list>a{padding:28px 0;border-bottom:1px solid var(--line);display:flex;gap:24px;justify-content:space-between;align-items:center;color:var(--ink);text-decoration:none}.unit-list>a:hover h2{text-decoration:underline}.unit-list h2{margin:12px 0;font:26px/1.4 Georgia,serif}.unit-list p{max-width:700px;margin:0 0 16px}.unit-list span{color:var(--accent);font-size:16px}.lesson-page{max-width:680px;padding-top:32px}.lesson-top{display:flex;align-items:center;gap:24px}.lesson-exit{font-size:16px}.lesson-progress{display:grid;grid-template-columns:repeat(3,1fr);gap:6px;flex:1}.lesson-progress span{height:5px;background:var(--line);border-radius:3px}.lesson-progress span.reached{background:var(--accent)}.quiet{background:transparent;border-color:transparent;color:var(--muted)}.quiet:hover{color:var(--accent)}.stage-label{text-align:center;margin:28px 0 12px;font-size:14px;color:var(--muted)}.lesson-page>.draft-label{text-align:center;margin:0 0 28px}.lesson-content{padding:16px 0 24px;min-width:0}.lesson-content h1{font:34px/1.4 Georgia,serif;margin-bottom:28px}.lesson-content p{line-height:1.8}.lesson-goal{color:var(--accent);font-size:19px}.lesson-content details{padding:18px 0;border-bottom:1px solid var(--line)}.lesson-content summary{cursor:pointer;color:var(--accent);font-size:16px;line-height:1.6;min-height:28px;text-decoration:underline;text-underline-offset:4px}.lesson-title-small{text-align:center!important;font-size:24px!important;color:var(--muted);margin:0!important}.lesson-excerpt{padding:44px 0;text-align:center}.lesson-excerpt .original{text-align:center;font-size:calc(var(--reading-size) + 4px);line-height:2.3;letter-spacing:.04em}.lesson-excerpt:has(ruby) .original{line-height:2.7}.lesson-content textarea{margin:12px 0}.note-copy{white-space:pre-wrap;overflow-wrap:anywhere}.completion-message{color:var(--accent);font-weight:500}.question-count{text-align:center;color:var(--muted);font-size:14px;margin:28px 0 20px}.exercise{border:0;padding:0;margin:0;min-width:0}.exercise legend{font-size:25px;line-height:1.6;margin-bottom:20px;padding:0;width:100%;text-align:left}.option{display:flex;align-items:center;gap:14px;min-height:48px;padding:16px 18px;border:1px solid var(--control);border-radius:10px;margin:12px 0;cursor:pointer;line-height:1.6}.option:has(input:checked){background:var(--soft);border:2px solid var(--accent);padding:15px 17px}.option input{width:20px;height:20px;flex-shrink:0;accent-color:var(--accent)}.feedback{background:var(--soft);padding:20px 24px;margin-top:24px;border-radius:10px}.feedback h3{font-size:20px;margin:0 0 12px}.feedback p{margin:0;font-size:16px}.feedback .quiet{margin-top:12px;color:var(--accent);padding-left:0}.lesson-content>details:has(+.step-actions){border-bottom:0}.step-actions{display:flex;align-items:center;justify-content:space-between;gap:12px;padding-top:28px;margin-top:28px;border-top:1px solid var(--line)}.step-actions .primary{margin-left:auto;min-width:160px;text-align:center;justify-content:center}.practice-help{margin-bottom:16px}@media(max-width:760px){body{font-size:17px}.learning-opening{padding:36px 0 48px}.learning-opening h1{font-size:36px}.home-description{font-size:17px}.lesson-page{width:calc(100% - 40px);padding-top:24px}.lesson-top{gap:14px}.lesson-top button{padding:8px;font-size:14px}.lesson-exit{font-size:14px}.lesson-content{padding:12px 0 24px}.lesson-content h1{font-size:29px}.lesson-content .lesson-title-small{font-size:20px!important}.stage-label{margin-top:20px}.lesson-page>.draft-label{margin-bottom:16px}.lesson-excerpt{padding:36px 0}.exercise legend{font-size:23px}.option{padding:14px 12px}.option:has(input:checked){padding:13px 11px}.step-actions .primary{min-width:140px}.feedback{padding:18px}.home-units .actions{gap:8px}}#practice-print{display:none}@media print{:root{color-scheme:light!important;background:#fff!important;--paper:#fff;--surface:#fff;--ink:#000}body[data-print-practice=true]{background:#fff!important;color:#000!important;font-size:11pt;margin:0;min-width:0;min-height:0;height:auto}body[data-print-practice=true]>*:not(#practice-print){display:none!important}body[data-print-practice=true]>#practice-print{display:block!important;background:#fff;color:#000}}.lesson-excerpt{padding:24px 0}.stage-label{margin:16px 0 8px}.lesson-page>.draft-label{margin-bottom:12px}.passage-citation{text-align:center;font-size:14px;color:var(--muted);margin:0 0 20px}.attribution{font-size:14px;color:var(--muted);line-height:1.6}@media(max-width:760px){.lesson-excerpt{padding:18px 0}.lesson-page>.draft-label{margin-bottom:12px}}.print-dialog{width:min(1080px,calc(100% - 32px));max-height:94dvh}.print-layout{display:grid;grid-template-columns:260px minmax(0,1fr);gap:24px}.print-settings{display:grid;gap:16px;align-content:start}.print-settings select{width:100%}.print-settings textarea{min-height:0}.print-settings details{font-size:16px}.print-settings .checkbox{margin-top:12px}.print-preview{min-width:0;container-type:inline-size}.sheet-stack{display:grid;gap:24px;background:var(--line);padding:12px;overflow:hidden}.practice-sheet{position:relative;box-sizing:border-box;width:var(--sheet-width);height:var(--sheet-height);padding:15mm;background:#fff;color:#000;font-family:Arial,sans-serif;flex-shrink:0;overflow:visible}.sheet-stack .practice-sheet{zoom:calc((100cqw - 24px) / var(--sheet-width))}.practice-sheet-heading{height:28mm;overflow:hidden}.practice-sheet-heading h2{font:16pt/1.3 Arial,sans-serif;margin:0 0 2mm}.practice-sheet-heading p{font:9pt/1.5 Arial,sans-serif;margin:0;overflow-wrap:anywhere}.practice-line{display:flex;width:max-content;margin-bottom:3mm;break-inside:avoid}.practice-box{width:var(--cell-size);flex:0 0 var(--cell-size)}.practice-pinyin{display:block;height:var(--pinyin-height);font:9pt/6mm Arial,sans-serif;text-align:center;color:#000}.practice-glyph{position:relative;isolation:isolate;display:grid;place-items:center;width:var(--cell-size);height:var(--cell-size);border:1px solid #000;font:calc(var(--cell-size)*.72)/1 var(--learning-han);color:#000}.practice-box+.practice-box .practice-glyph{border-left:0}.practice-box.trace .practice-glyph{color:#b3b3b3}.midlines .practice-glyph:before,.midlines .practice-glyph:after{content:"";position:absolute;z-index:-1;pointer-events:none}.midlines .practice-glyph:before{width:100%;left:0;top:50%;border-top:1px dashed #999}.midlines .practice-glyph:after{height:100%;top:0;left:50%;border-left:1px dashed #999}.practice-page-number{position:absolute;bottom:15mm;left:15mm;font:9pt/1.4 Arial,sans-serif}.print-actions{display:flex;gap:12px;align-items:center;flex-wrap:wrap;margin-top:24px;padding-top:20px;border-top:1px solid var(--line)}@media(max-width:760px){.print-dialog{width:100%;height:100dvh;max-width:100%;max-height:100dvh;margin:0;border:0;border-radius:0;padding:20px}.print-layout{grid-template-columns:1fr}.print-settings{grid-template-columns:1fr 1fr;gap:16px}.print-settings>details,.print-settings>p,.print-settings>label:has(textarea){grid-column:1/-1}.print-settings select{min-width:0}.print-actions{position:static;padding-bottom:env(safe-area-inset-bottom)}}@media print{body[data-print-practice=true]>#practice-print{width:auto!important}#practice-print>.practice-sheet{width:calc(var(--sheet-width) - 30mm);height:calc(var(--sheet-height) - 30mm);padding:0;margin:0;zoom:1;break-after:page;page-break-after:always;break-inside:avoid;print-color-adjust:exact;-webkit-print-color-adjust:exact}#practice-print>.practice-sheet:last-child{break-after:auto;page-break-after:auto}#practice-print .practice-sheet-heading{margin:0;height:28mm;break-after:auto}#practice-print .practice-sheet-heading h2{font:16pt/1.3 Arial,sans-serif;margin:0 0 2mm}#practice-print .practice-sheet-heading p{font:9pt/1.5 Arial,sans-serif;margin:0}#practice-print .practice-page-number{left:0;bottom:0;margin:0;font:9pt/1.4 Arial,sans-serif}}.header-settings{display:flex;align-items:center;gap:8px}.header-settings>button:first-child{font-size:14px;min-height:44px}@media(max-width:760px){.site-header .header-settings{margin-left:auto}.site-header nav{order:3;width:100%}}@media(max-width:760px){.site-header{gap:12px}.site-header .brand{padding-right:0}.site-header .header-settings .theme-toggle{position:static;margin-left:0}}.lesson-explanation{margin:0 0 24px;text-align:left}.lesson-explanation h2{font-family:inherit;font-size:18px;font-weight:500;line-height:1.5;color:var(--ink);margin:0 0 10px}.lesson-explanation>p{font-family:inherit;font-size:18px;font-weight:400;line-height:1.8;margin:0}.lesson-explanation>p.attribution{font-size:14px;line-height:1.6;margin-top:12px}@media(max-width:760px){.lesson-explanation>p:not(.attribution){font-size:17px}}.unit-summary h2{font-family:var(--learning-han);font-weight:400;font-size:28px;line-height:1.8;overflow-wrap:anywhere;margin:12px 0}.unit-summary .unit-meaning{font-family:inherit;font-size:18px;line-height:1.8;color:var(--ink);margin:0 0 16px}.learning-opening .unit-summary{margin:24px auto 0;max-width:600px}.unit-list>a>div{min-width:0}.unit-list>a>span{flex-shrink:0}@media(max-width:760px){.unit-summary h2{font-size:24px}.unit-summary .unit-meaning{font-size:17px}}