:root{--paper:#faf7ef;--white:#fffdfa;--ink:#082b4f;--muted:#627782;--blue:#81c4ec;--pale-blue:#e1eff7;--orange:#e97640;--sage:#aabd9b;--pale-sage:#e8eedf;--line:#d9ded4;--serif:"Songti SC","STSong","SimSun",serif;--sans:-apple-system,BlinkMacSystemFont,"PingFang SC","Microsoft YaHei",sans-serif}
*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;color:var(--ink);background:var(--paper);font-family:var(--sans);font-size:15px;line-height:1.6;background-image:radial-gradient(#a0a18a12 .6px,transparent .6px);background-size:8px 8px}button,input{font:inherit}button{cursor:pointer;color:inherit;border:1px solid var(--line);background:var(--white);border-radius:5px;padding:8px 13px}button:hover:not(:disabled){border-color:var(--orange);background:#fff4e8}button:focus-visible,input:focus-visible,a:focus-visible{outline:3px solid var(--orange);outline-offset:3px}button:disabled{opacity:.4;cursor:default}button[hidden],[hidden]{display:none!important}h1,h2,h3,p{margin-top:0}h1,h2,h3{font-family:var(--serif);font-weight:800}h1{font-size:clamp(34px,3.5vw,57px);letter-spacing:-1px;line-height:1.15;margin:8px 0 0}h1 em{font-style:normal}h2{font-size:clamp(28px,2.5vw,42px);line-height:1.3;margin:4px 0 0}h3{font-size:25px;line-height:1.4}small{font-size:12px;color:var(--muted)}.eyebrow{font-size:12px;letter-spacing:.11em;color:var(--muted);display:block;line-height:1.5}.eyebrow i{display:inline-block;height:8px;width:8px;background:var(--orange);border-radius:50%;margin:0 10px}.masthead{max-width:1760px;margin:auto;padding:25px 42px 27px;display:flex;gap:24px;justify-content:space-between;align-items:center;border-bottom:1px solid var(--line)}.course-meta{display:flex;gap:12px;align-items:center;font-size:13px;white-space:nowrap}.course-meta>span{padding:5px 10px;border-left:2px solid var(--sage)}.quiet{background:transparent;border-color:transparent;text-decoration:underline;text-underline-offset:5px}.app-layout{display:grid;grid-template-columns:280px minmax(0,1fr);max-width:1760px;margin:auto;min-height:80vh}.sidebar{border-right:1px solid var(--line);padding:24px 20px 35px 28px;position:sticky;top:0;height:100vh;overflow:auto;scrollbar-width:thin}.search-label{display:block;font-family:var(--serif);font-size:21px;font-weight:800;margin-bottom:10px}.search-wrap{display:flex;align-items:center;border:1px solid #b6c5c9;background:var(--white);border-radius:5px;padding:0 8px}.search-wrap>span{font-size:26px;line-height:1}.search-wrap input{width:100%;border:0;background:none;outline:none;padding:10px 7px;min-width:0;font-size:13px;color:var(--ink)}.search-wrap:focus-within{outline:2px solid var(--blue)}.search-wrap button{padding:0 4px;border:0;font-size:22px}.search-status{font-size:12px;color:var(--muted);min-height:18px;margin:6px 0 11px}.reading-progress{margin:0 0 20px;font-size:12px;color:var(--muted)}progress{display:block;width:100%;height:4px;border:0;margin-top:8px;border-radius:3px;accent-color:var(--orange)}progress::-webkit-progress-bar{background:#e5e6dd}progress::-webkit-progress-value{background:var(--orange)}.chapter-group{border-bottom:1px solid var(--line);padding:8px 0}.chapter-button{display:flex;align-items:baseline;width:100%;gap:9px;text-align:left;border:0;background:transparent;padding:9px 4px;font-weight:600;font-size:14px;line-height:1.5}.chapter-number{font-family:var(--serif);font-size:21px;color:#a96335;min-width:25px}.chapter-button small{margin-left:auto;font-weight:400}.chapter-lessons{padding:3px 0 8px 28px;display:grid;gap:3px}.scene-button{border:0;background:transparent;text-align:left;padding:8px 10px;line-height:1.45;font-size:13px;display:flex;gap:7px;width:100%}.scene-button[aria-current=true]{background:var(--pale-blue);box-shadow:-3px 0 var(--orange);font-weight:600}.scene-button .check{color:#658453;min-width:12px;font-size:12px}.scene-button .scene-num{color:var(--muted);font:10px/1.6 monospace}.sidebar-note{font-family:var(--serif);font-size:14px;color:var(--muted);border-left:3px solid var(--sage);padding-left:12px;margin:25px 6px}main{min-width:0;padding:23px 35px 45px}.lesson-toolbar{display:flex;justify-content:space-between;align-items:center;gap:15px;font-size:12px}.chapter-label{background:var(--pale-sage);padding:5px 11px;clip-path:polygon(0 3%,100% 0,98% 100%,1% 96%)}.pager{display:flex;align-items:center;gap:10px}.pager button{font-size:12px;padding:6px 9px;background:none;border-color:transparent}.pager span{color:var(--muted);font-variant-numeric:tabular-nums}.lesson-heading{display:flex;align-items:flex-end;justify-content:space-between;gap:24px;padding:23px 0 20px}.lesson-heading .eyebrow{font-size:11px;margin-bottom:6px}.complete-button{white-space:nowrap;font-size:12px;margin-bottom:4px;background:none}.complete-button[aria-pressed=true]{background:var(--pale-sage);border-color:var(--sage)}.image-stage{position:relative;background:var(--paper);box-shadow:6px 8px 0 #e5e0d5;border:1px solid #d9d8ce;border-radius:2px;overflow:hidden}.image-stage:before{content:"";position:absolute;z-index:1;width:100px;height:22px;background:#e8c993c4;left:calc(50% - 50px);top:-7px;transform:rotate(4deg)}.image-stage>img{display:block;width:100%;height:auto;aspect-ratio:16/9;object-fit:contain}.zoom-button{position:absolute;right:13px;bottom:13px;font-size:12px;background:#fffdfae8;border-color:#d1d7ce}.image-stage #image-fallback{position:absolute;top:45%;left:10%;right:10%;text-align:center;background:var(--white);padding:20px}.step-toolbar{margin-top:20px;display:flex;align-items:center;gap:10px;flex-wrap:wrap}.step-toolbar>button{border-radius:50%;height:34px;width:34px;padding:0;font-size:17px;background:none}#step-buttons{display:flex;gap:6px}#step-buttons button{min-width:30px;height:32px;padding:0 7px;font-size:12px;background:none}#step-buttons button[aria-current=step]{background:var(--ink);border-color:var(--ink);color:var(--paper)}#step-caption{font-size:12px;color:var(--muted);margin-left:4px}.keyboard-hint{margin-left:auto;color:var(--muted);font-size:11px;white-space:nowrap}kbd{display:inline-block;font:10px var(--sans);padding:2px 6px;border:1px solid var(--line);border-bottom-width:2px;border-radius:3px;margin-right:3px}.lesson-bottom{display:grid;grid-template-columns:minmax(0,1fr) 250px;gap:27px;margin-top:27px}.notes-panel{min-width:0}.tabs{display:flex;border-bottom:1px solid var(--line);gap:16px;margin-bottom:17px}.tabs button{border:0;border-radius:0;padding:9px 0;background:none;font-size:14px;color:var(--muted)}.tabs button[aria-selected=true]{border-bottom:3px solid var(--orange);font-weight:600;color:var(--ink)}[role=tabpanel]{font-size:15px;line-height:1.95;min-height:125px}[role=tabpanel] p{margin-bottom:12px}#panel-points ul{list-style:none;margin:0;padding:0}#panel-points li{position:relative;padding:6px 0 6px 23px}#panel-points li:before{content:"";position:absolute;left:0;top:16px;width:9px;height:9px;background:var(--orange);transform:rotate(-10deg)}.resource-note{background:var(--pale-sage);padding:24px 22px 20px;position:relative;align-self:start;box-shadow:4px 5px 0 #e4e3d8;clip-path:polygon(0 1%,100% 0,99% 97%,89% 100%,77% 98%,62% 100%,45% 98%,32% 100%,18% 98%,0 100%)}.resource-note p{font-family:var(--serif);font-size:28px;margin:9px 0 15px;font-variant-numeric:tabular-nums}.primary-button{background:var(--ink);color:var(--paper);border-color:var(--ink);font-size:13px;padding:11px 15px}.primary-button:hover:not(:disabled){background:#174568;color:white;border-color:var(--ink)}.resource-note small{display:block;line-height:1.7;margin-top:16px}.quiz-panel{position:relative;background:var(--pale-blue);margin-top:27px;padding:24px 29px 25px;border:1px solid #b7d3e4;box-shadow:5px 6px 0 #e2e2d7}.quiz-panel h3{margin:9px 0 19px}.quiz-panel .eyebrow{margin-bottom:0}#quiz-options{display:grid;grid-template-columns:1fr 1fr;gap:13px}#quiz-options button{text-align:left;background:var(--white);padding:16px 18px;border:2px solid transparent;line-height:1.6;display:flex;gap:12px}#quiz-options button b{font-family:var(--serif);font-size:20px}#quiz-options button.correct{background:var(--pale-sage);border-color:#829c70}#quiz-options button.incorrect{background:#f9e0cf;border-color:var(--orange)}#quiz-result{border-left:3px solid var(--orange);padding:3px 0 3px 14px;margin-top:18px;line-height:1.8}#quiz-reset{font-size:12px;padding:5px 0;margin-top:8px}.evidence-label{display:inline-block;background:var(--pale-sage);padding:3px 9px;font-size:12px;margin-bottom:12px}.source-list{display:flex;gap:7px;flex-wrap:wrap}.source-list span{font:12px monospace;border:1px solid var(--line);padding:3px 7px}.code-block{white-space:pre-wrap;overflow-wrap:anywhere;background:#e8eee9;border-left:3px solid var(--sage);padding:16px;font:13px/1.8 Menlo,Consolas,monospace}.page-footer{max-width:1760px;margin:auto;border-top:1px solid var(--line);padding:19px 35px 30px;color:var(--muted);font-size:12px;display:flex;justify-content:space-between;gap:20px}dialog{border:1px solid var(--line);border-radius:8px;padding:32px;background:var(--paper);color:var(--ink);max-width:min(900px,94vw);max-height:94vh;overflow:auto;box-shadow:0 20px 100px #082b4f44}dialog::backdrop{background:#092b4fb3;backdrop-filter:blur(4px)}.dialog-close{position:absolute;right:10px;top:9px;z-index:1;border:0;background:#fffdfae8;font-size:25px;line-height:1;padding:7px 10px;border-radius:50%}#image-dialog{max-width:96vw;width:1500px;padding:15px}#image-dialog img{width:100%;height:auto;display:block}#image-dialog p{font-size:11px;text-align:center;color:var(--muted);margin:8px 0 0}#help-dialog{width:650px;padding:43px}#help-dialog h2{margin:10px 0 22px}#help-dialog ol{padding-left:20px;line-height:2.1}#help-dialog p{color:var(--muted)}.skip-link{position:absolute;left:20px;top:-70px;background:var(--ink);color:white;padding:12px;z-index:10}.skip-link:focus{top:10px}noscript{display:block;padding:25px;text-align:center;background:#f8dfc7}
@media(min-width:1700px){main{padding-left:43px;padding-right:43px}.sidebar{padding-left:35px}.app-layout{grid-template-columns:300px 1fr}}
@media(max-width:1100px){.masthead{padding:23px 25px}.course-meta{flex-wrap:wrap;max-width:200px;gap:5px}.app-layout{grid-template-columns:230px 1fr}.sidebar{padding:23px 13px 25px 17px}main{padding:23px 24px}.lesson-bottom{grid-template-columns:1fr}.resource-note{display:grid;grid-template-columns:1fr auto;gap:0 20px}.resource-note p{margin:5px 0}.resource-note .primary-button{grid-row:1/3;grid-column:2;align-self:center}.resource-note small{grid-column:1/-1;margin-top:8px}.keyboard-hint{display:none}.complete-button{padding:6px}.lesson-heading{gap:12px}.lesson-toolbar{align-items:flex-start;flex-direction:column;gap:8px}}
@media(max-width:760px){.masthead{padding:22px 18px;align-items:flex-start}.masthead h1{font-size:31px}.masthead h1 em{display:block;margin-top:5px}.masthead .eyebrow{font-size:10px}.course-meta{flex-direction:column;align-items:flex-end;max-width:140px;font-size:11px}.course-meta>span{border-left:0;padding:2px}.app-layout{display:block}.sidebar{position:relative;top:auto;height:auto;max-height:360px;padding:20px;border:0;border-bottom:1px solid var(--line)}.search-label{font-size:19px}.reading-progress{display:none}.sidebar-note{display:none}#chapter-nav{display:grid;grid-template-columns:1fr 1fr;gap:0 15px}.chapter-group{align-self:start}.chapter-button{font-size:12px}.chapter-lessons{padding-left:0}.chapter-number{font-size:18px;min-width:21px}.scene-button{font-size:12px}main{padding:21px 18px}.lesson-toolbar{flex-direction:row;align-items:center}.chapter-label{max-width:45%;font-size:11px}.pager{gap:1px}.pager span{font-size:10px}.pager button{font-size:10px;padding:5px}.lesson-heading{align-items:flex-start;padding:19px 0 18px}.lesson-heading h2{font-size:28px}.complete-button{font-size:10px;white-space:normal;width:64px;flex-shrink:0}.step-toolbar{gap:7px}#step-caption{width:100%;margin-top:2px}.step-toolbar>button{width:30px;height:30px}#step-buttons{gap:4px}#step-buttons button{min-width:26px;height:29px}.quiz-panel{padding:21px 18px}#quiz-options{grid-template-columns:1fr}.quiz-panel h3{font-size:22px}.tabs{gap:18px}.tabs button{font-size:13px}[role=tabpanel]{font-size:14px}.resource-note{padding:19px 17px}.resource-note p{font-size:24px}.resource-note .primary-button{font-size:12px}.page-footer{padding:20px;flex-direction:column;gap:4px;font-size:11px}#help-dialog{padding:35px 25px}.zoom-button{padding:4px 8px;font-size:10px}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*{animation:none!important;transition:none!important}}
#quiz-options button:disabled{opacity:1}.source-list a{font-size:12px;line-height:1.5;padding:4px 8px;color:var(--ink);border:1px solid var(--line);border-radius:3px;text-decoration:none}.source-list a:hover{background:var(--pale-blue);border-color:var(--blue)}
.steps-heading{font-size:20px;margin:22px 0 9px}#panel-points ol{margin:0;padding-left:24px}#panel-points ol li{padding:5px 0 5px 5px}#panel-points ol li:before{display:none}
/* The video frames reserve 220px for subtitles; the interactive guide shows
   their 860px teaching region. Enlarged originals retain the full frame. */
.image-stage>img{margin-bottom:-11.458333333%}

/* Online resource panel; the original teaching artwork stays unchanged. */
.site-return{max-width:1760px;margin:0 auto;padding:15px 42px 0;font-size:13px}.site-return a{color:var(--ink);text-decoration:none}.site-return a:hover{text-decoration:underline}.resource-note{display:block}.resource-note .resource-title{font-size:25px;margin:9px 0 12px}.resource-note a.primary-button{display:inline-block;text-decoration:none}.resource-note details{margin-top:18px;font-size:13px}.resource-note summary{cursor:pointer;font-weight:600}.resource-links{display:grid;gap:10px;margin:13px 0 6px}.resource-links a{color:var(--ink);text-underline-offset:3px;overflow-wrap:anywhere}.resource-note .resource-explanation{font-family:var(--sans);font-size:12px;line-height:1.8;color:var(--muted);margin:15px 0 0}.resource-note small{margin-top:15px}.page-footer a{color:var(--ink)}
@media(max-width:760px){.site-return{padding:12px 18px 0}.resource-note{display:block}.resource-note .resource-title{font-size:24px}}

/* Direct reading entry, following the course paper-and-ink palette. */
.site-return{display:flex;align-items:center;justify-content:space-between;gap:16px;flex-wrap:wrap}.site-return .script-shortcut{display:inline-flex;align-items:center;gap:14px;padding:7px 12px;background:var(--pale-blue);border-bottom:2px solid var(--blue);font-weight:600;font-size:12px;text-decoration:none}.site-return .script-shortcut:hover{background:#d4e8f4}.reader-entry{display:block;padding:14px 12px;margin:0 0 16px;color:var(--ink);background:var(--white);border-left:3px solid var(--orange);text-decoration:none}.reader-entry strong{display:flex;justify-content:space-between;gap:12px;font-size:14px;line-height:1.6}.reader-entry>span{display:block;margin-top:5px;font-size:11px;color:#526a76;line-height:1.6}.reader-entry:hover{background:var(--pale-blue)}
@media(max-width:460px){.site-return{gap:10px}.site-return .script-shortcut{font-size:11px;gap:8px;padding:6px 8px}}