/* The introduction has one persistent toolbar. Optional reading/navigation panels sit above it. */
.nell-intro{--ink:#153447;--accent:#087f84;box-sizing:border-box;width:min(1240px,calc(100vw - 32px));height:min(800px,94dvh);max-height:94dvh;border:1px solid #d8e3e8;border-radius:22px;background:#f8fbfc;color:var(--ink);padding:0;box-shadow:0 24px 100px #102f4645;overflow:hidden;font:16px/1.6 system-ui,sans-serif}
.nell-intro[open]{display:grid;grid-template-rows:auto minmax(0,1fr) auto}
.nell-intro::backdrop{background:#102f467a;backdrop-filter:blur(5px)}
.nell-intro *{box-sizing:border-box}
.nell-intro header{width:100%;max-width:none;justify-self:stretch;display:flex;align-items:center;gap:24px;padding:20px 32px;border-bottom:1px solid #e1e9eb}
.nell-intro header img{width:94px;height:auto}.nell-intro header>div{flex:1}.nell-intro header span{color:#496170;font-size:12px}.nell-intro-caption{display:block;font-size:11px;color:#647985;margin-top:2px}
.nell-intro button{font:inherit;color:var(--ink);min-height:44px;border:1px solid #bacfd2;border-radius:9px;padding:9px 15px;background:white;cursor:pointer}
.nell-intro button:disabled{opacity:.35;cursor:default}.nell-intro button:focus-visible{outline:3px solid var(--accent);outline-offset:3px}.nell-intro header button{font-size:12px;border-color:transparent;background:transparent}
.nell-intro-layout{overflow:auto;overscroll-behavior:contain;padding:36px 42px;display:grid;align-items:center}
.nell-intro [data-slide]{display:grid;grid-template-columns:minmax(0,1.05fr) minmax(0,1fr);gap:48px;align-items:center}
.nell-intro-kicker{text-transform:uppercase;letter-spacing:.13em;color:var(--accent);font-size:10px;font-weight:750;margin:0 0 16px}
.nell-intro h2{font:400 clamp(30px,3.5vw,44px)/1.13 Georgia,serif;letter-spacing:-.025em;margin:0 0 22px;text-wrap:balance}.nell-intro h2:focus{outline:none}
.nell-intro-lead{font-size:18px;line-height:1.5;color:#496170;margin:0 0 20px}
.nell-intro-copy ul{list-style:none;margin:0;padding:0}.nell-intro-copy li{padding:10px 0 10px 20px;position:relative;border-bottom:1px solid #dfe9ea;font-size:14px;line-height:1.6}.nell-intro-copy li:before{content:'·';position:absolute;left:2px;color:var(--accent);font-weight:700}
.nell-intro blockquote{font:italic 20px/1.5 Georgia,serif;color:var(--accent);margin:22px 0 0}
.nell-intro [data-action]{margin-top:20px;color:var(--accent);border:0;border-bottom:1px solid #bad6d5;border-radius:0;background:transparent;padding:4px 0;font-size:13px;text-align:left}
.nell-intro-controls{position:relative;background:#fff;border-top:1px solid #e1e9eb;padding:17px 30px 18px}
.nell-intro progress{position:absolute;top:-3px;left:0;width:100%;height:3px;border:0;border-radius:0;accent-color:var(--accent);background:#e5eded}.nell-intro progress::-webkit-progress-bar{background:#e5eded}.nell-intro progress::-webkit-progress-value{background:var(--accent)}
.nell-intro-toolbar{display:flex;align-items:center;justify-content:space-between;gap:16px}
.nell-intro [data-toggle]{display:flex;align-items:center;gap:10px;border:0;background:transparent;padding:8px;font-size:12px;color:#496170}.nell-intro [data-count]{font-variant-numeric:tabular-nums;font-weight:650;color:var(--ink)}
.nell-intro-playback{display:flex;align-items:center;gap:12px}.nell-intro [data-prev],.nell-intro [data-next]{border:0;background:#f0f5f5;border-radius:50%;width:44px;padding:0;font-size:20px}
.nell-intro [data-play]{background:var(--ink);color:white;min-width:165px;border-color:var(--ink);border-radius:25px;font-size:14px}
.nell-intro [data-audio-status]{font-size:12px;color:#7a4834;max-width:800px;margin:12px auto 0;text-align:center}.nell-intro [data-audio-status]:empty{display:none}
.nell-intro-panel{position:absolute;z-index:2;bottom:90px;left:28px;right:28px;max-height:calc(100% - 190px);overflow:auto;overscroll-behavior:contain;padding:20px 28px 28px;background:#fff;border:1px solid #d4e1e2;border-radius:16px;box-shadow:0 -8px 48px #15344726}
.nell-intro-panel-heading{display:flex;align-items:center;justify-content:space-between;gap:16px;margin-bottom:12px}.nell-intro-panel h3{font:400 26px/1.3 Georgia,serif;margin:0}.nell-intro-panel-heading button{border:0;background:#f0f5f5;padding:0;width:44px;flex-shrink:0;font-size:22px}
.nell-intro [data-chapters]{display:grid;grid-template-columns:1fr 1fr;gap:5px 20px}.nell-intro [data-chapter]{display:flex;align-items:center;gap:12px;text-align:left;background:transparent;border-color:transparent;font-size:13px;padding:10px}.nell-intro [data-chapter] span{color:#69828b;font-variant-numeric:tabular-nums}.nell-intro [data-chapter]:hover{background:#f0f5f5}.nell-intro [data-chapter][aria-current]{background:#e3f4f1;border-color:#c2ded8;color:#00656b}.nell-intro [data-transcript]{max-width:850px;margin:0;font-size:16px;line-height:1.9}
.nell-intro [hidden]{display:none!important}.nell-intro>audio{display:none}
.nell-intro-launch{margin:12px 0;padding:12px 17px;font:inherit;background:#e3f4f1;color:#153447;border:1px solid #bacfd2;border-radius:10px;cursor:pointer;min-height:44px}
/* Chapter-specific, explicitly illustrative views. */
.nell-intro-scene{margin:0;min-width:0;border-radius:18px;background:#eaf2f1;border:1px solid #d7e5e3;box-shadow:0 18px 30px -25px #17414666;overflow:hidden}
.intro-demo-heading{padding:16px 22px;display:flex;align-items:center;gap:9px;font-size:11px;letter-spacing:.01em;color:#4d696c;background:#f2f7f6;border-bottom:1px solid #d7e5e3}.intro-demo-dot{height:7px;width:7px;background:#15938d;border-radius:50%;flex-shrink:0}
.intro-demo-stage{padding:26px;min-height:345px;display:grid;align-items:center;background:radial-gradient(ellipse at top right,#fff9,transparent 65%)}
.nell-intro-scene figcaption{margin:0;padding:12px 20px;background:#f2f7f6;border-top:1px solid #d7e5e3;color:#526e74;font-size:10px;line-height:1.6}
.intro-demo-stage h3{font:400 25px/1.25 Georgia,serif;letter-spacing:-.01em;margin:10px 0 14px}.intro-demo-stage p{margin:6px 0;font-size:14px;line-height:1.6}
.intro-demo-paper{background:#fff;border:1px solid #d6e4e2;border-radius:10px;padding:22px;box-shadow:0 6px 15px #15344706}.intro-demo-eyebrow{font-size:9px;text-transform:uppercase;letter-spacing:.14em;color:#527779;font-weight:650}
.intro-demo-stack{display:grid;gap:12px}.intro-demo-stack.compact{margin-top:16px;gap:8px}.intro-demo-step{display:flex;align-items:center;gap:14px;padding:13px 15px;border-radius:10px;background:#fffc;border:1px solid #d6e4e2}.intro-demo-step>b{font:400 24px Georgia,serif;color:#087f84;min-width:29px}.intro-demo-step strong{font-weight:650;font-size:13px}.intro-demo-step p{font-size:12px;color:#526e74;margin:2px 0 0}.compact .intro-demo-step{padding:10px 12px}.intro-demo-paper .intro-demo-step{border:0;background:#f3f7f6}
.intro-demo-bubble{display:flex;gap:12px;align-items:center;margin-top:20px}.intro-demo-bubble img{width:42px;height:48px;object-fit:contain;flex-shrink:0}.intro-demo-bubble p{background:#fff;border:1px solid #cbded9;border-radius:12px 12px 12px 2px;padding:12px 15px;font:italic 17px/1.45 Georgia,serif;color:#176e70;margin:0}
.intro-demo-welcome{text-align:center}.intro-demo-welcome>img{width:148px;height:156px;object-fit:contain;filter:drop-shadow(0 8px 14px #0a776f19)}.intro-demo-welcome>span{display:block;font-size:10px;font-weight:750;letter-spacing:.22em;color:#177d7b;margin:12px 0}.intro-demo-welcome h3{font-size:29px}.intro-demo-welcome p{color:#526e74}
.intro-demo-tags{display:flex;justify-content:center;flex-wrap:wrap;gap:6px;margin-top:20px}.intro-demo-tags span{background:#fff;border:1px solid #cddfdb;border-radius:20px;font-size:10px;padding:5px 10px;color:#247d7b}
.intro-demo-choice{display:grid;grid-template-columns:1fr 1fr;gap:10px;margin-top:18px}.intro-demo-choice span{display:grid;align-items:center;text-align:center;background:#eaf4f1;border:1px solid #cddfdb;border-radius:8px;padding:12px 7px;font-size:12px;color:#236963}
.intro-demo-answer>p{margin:23px 0;font:italic 17px/1.6 Georgia,serif}.intro-demo-mark{position:relative;padding-right:22px}.intro-demo-mark b{display:inline-block;margin-left:8px;font:700 22px Georgia,serif;opacity:0;transform:scale(.5)}.intro-demo-mark.good[data-reached=true]{color:#167756}.intro-demo-mark.good[data-reached=true] b,.intro-demo-mark.wrong[data-reached=true] b{opacity:1;transform:none}.intro-demo-mark.wrong[data-reached=true]{color:#a53b3b;text-decoration:line-through;text-decoration-thickness:2px}.intro-demo-mark.wrong b{color:#b13a3a;text-decoration:none}
.intro-demo-stage .intro-demo-note{font:italic 15px/1.6 Georgia,serif;color:#9a453d}.intro-scene-feedback .intro-demo-note{color:#167756}
.intro-demo-reminder{text-align:center;color:#39796f;margin-top:18px;padding:10px;border:1px dashed #b4cfca;border-radius:9px;font-size:12px}
.intro-demo-media{display:grid;grid-template-columns:1fr 1fr;gap:12px}.intro-demo-media>div{display:flex;flex-direction:column;align-items:flex-start;background:#fff;padding:20px 16px;border:1px solid #d1e2de;border-radius:12px}.intro-demo-media b{font:400 29px/1 Georgia,serif;color:#138282;margin-bottom:18px}.intro-demo-media strong{font-size:12px}.intro-demo-media span{font-size:10px;color:#61777d;margin-top:5px}.intro-demo-stage .intro-demo-footnote{font-size:12px;color:#4a7574;text-align:center;margin:20px 0 0}
.intro-demo-meter{display:flex;height:62px;align-items:center;gap:3px;margin:12px 0}.intro-demo-meter i{display:block;width:4px;height:var(--bar);background:#168d86;border-radius:3px;transform:scaleY(.35);animation:intro-meter .65s ease-in-out infinite alternate;animation-delay:var(--delay);animation-play-state:paused}.intro-demo-meter span{margin-left:auto;color:#417b77;font-size:10px}.nell-intro[data-dictating=true][data-speaking=true] .intro-demo-meter i{animation-play-state:running}
.intro-demo-dictation{min-height:75px}.intro-demo-dictation span{display:inline}.intro-demo-draft{border-top:1px solid #d7e5e3;margin-top:14px;padding-top:12px;font-size:11px;color:#207971}
.intro-demo-report small{font-size:10px;color:#417b77}.intro-demo-report>div{margin-top:15px}.intro-demo-report>div>p{font-size:13px;margin:5px 0 0;padding:10px;background:#f3f7f6;border-radius:5px}
.intro-demo-preference{margin-top:24px}.intro-demo-preference small{font-size:12px;color:#526e74}.intro-demo-preference>div{display:flex;justify-content:space-between;gap:3px;margin-top:10px;padding:4px;background:#edf3f2;border-radius:8px;align-items:center;font-size:9px}.intro-demo-preference span,.intro-demo-preference strong{padding:8px 6px}.intro-demo-preference strong{color:#126e65;background:#fff;border-radius:5px;font-weight:650;box-shadow:0 1px 4px #143c3512}
.intro-demo-recipient{display:flex;align-items:center;gap:14px;padding:10px 0;margin-top:15px;border-block:1px solid #d7e5e3;font-size:12px}.intro-demo-recipient span{color:#61777d}.intro-demo-plan{display:inline-block;border:1px solid #dfccb5;background:#fcf4e7;color:#8a6440;padding:5px 12px;border-radius:6px;font-size:10px;margin-bottom:16px}.nell-intro[data-chapter='11'] .nell-intro-kicker,.nell-intro[data-chapter='11'] blockquote{color:#936444}
/* Cues follow audio time. Without sound or with quiet mode, the whole example is visible. */
.nell-intro [data-cue][data-reached=false]:not(.intro-demo-mark){opacity:.15;transform:translateY(5px)}.nell-intro .intro-demo-mark[data-reached=false]{opacity:1}
@keyframes intro-meter{to{transform:scaleY(1)}}
@media(prefers-reduced-motion:no-preference){.nell-intro[data-motion=on] [data-cue],.nell-intro[data-motion=on] .intro-demo-mark b{transition:opacity .5s ease,transform .5s ease,color .3s}}
.nell-intro[data-motion=off] .intro-demo-meter i{animation:none;transform:scaleY(.65)}
@media(max-width:900px){.nell-intro-layout{padding:30px}.nell-intro [data-slide]{gap:28px}.intro-demo-stage{padding:20px}.intro-demo-paper{padding:18px}.nell-intro h2{font-size:34px}.nell-intro-lead{font-size:16px}}
@media(max-width:700px){.nell-intro{width:calc(100vw - 16px);height:96dvh;max-height:96dvh;border-radius:15px}.nell-intro header{padding:12px 16px;gap:12px}.nell-intro header img{width:72px}.nell-intro header>div{display:none}.nell-intro header button{margin-left:auto;font-size:11px;padding:6px}.nell-intro-layout{display:block;padding:26px 23px 30px}.nell-intro [data-slide]{grid-template-columns:1fr;gap:28px}.nell-intro h2{font-size:34px;margin-bottom:17px}.nell-intro-lead{font-size:17px}.nell-intro-copy li{font-size:13px}.nell-intro blockquote{font-size:19px;margin-top:18px}.intro-demo-stage{min-height:280px;padding:22px}.intro-demo-welcome>img{width:125px;height:130px}.nell-intro-controls{padding:12px 10px}.nell-intro-toolbar{gap:5px}.nell-intro [data-toggle]{gap:5px;padding:5px;min-width:44px;justify-content:center}.nell-intro-control-label{display:none}.nell-intro-playback{gap:5px}.nell-intro [data-play]{min-width:112px;padding:9px 10px;font-size:12px}.nell-intro [data-prev],.nell-intro [data-next]{width:38px;min-height:44px}.nell-intro-panel{left:12px;right:12px;bottom:80px;max-height:calc(100% - 165px);padding:18px}.nell-intro [data-chapters]{grid-template-columns:1fr}.nell-intro-panel h3{font-size:23px}.nell-intro [data-transcript]{font-size:15px}}
@media(max-width:360px){.nell-intro-layout{padding:24px 18px}.nell-intro [data-play]{min-width:96px}.nell-intro-playback{gap:2px}.nell-intro [data-count]{font-size:10px}.intro-demo-stage{padding:16px}}
.nell-intro-controls{min-width:0}.nell-intro-panel h3{min-width:0;overflow-wrap:anywhere;hyphens:auto}
@media(max-width:360px){.nell-intro [data-play]{min-width:44px;width:44px;font-size:0;padding:0}.nell-intro [data-play]:before{content:'▶';font-size:16px}.nell-intro[data-speaking=true] [data-play]:before{content:'Ⅱ'}.nell-intro [data-prev],.nell-intro [data-next]{width:44px}.nell-intro [data-toggle=chapters]>span:last-child{display:none}}

/* The literary inspiration is a diagram, not a reproduced book cover. */
.intro-demo-origin-book{width:78%;margin:0 auto 18px;padding:19px 24px 20px 30px;background:linear-gradient(90deg,#173543 7px,#294958 8px,#173543 15px);border:1px solid #456674;border-radius:3px 9px 9px 3px;box-shadow:5px 5px 0 #cedbd6,8px 8px 0 #dce6e1;color:#f2f5e9;transform:rotate(-2deg)}
.intro-demo-origin-book>span{font-size:10px;letter-spacing:.07em}.intro-demo-origin-book h3{font:400 28px/1.1 Georgia,serif;margin:12px 0}.intro-demo-origin-book small{font-size:10px;color:#d2e3db}.intro-scene-origin .intro-demo-bubble{margin-top:16px}
.nell-intro-sources{display:flex;flex-wrap:wrap;gap:10px 24px;margin-top:20px;padding-top:16px;border-top:1px solid #d7e5e3;font-size:12px}.nell-intro-sources:empty{display:none}.nell-intro-sources a{color:var(--accent);text-underline-offset:3px}.nell-intro-sources a:focus-visible{outline:3px solid var(--accent);outline-offset:3px}