:root{--ink:#163d35;--green:#276450;--mint:#bde6d1;--light:#eaf3ee;--paper:#f7faf8;--muted:#60756d;--line:#d9e3dd;--dark:#102f29;--bar:72px;--shadow:0 24px 80px #061b2633}
*{box-sizing:border-box}html,body{margin:0;width:100%;height:100%;overflow:hidden}body{font-family:"PingFang SC","Microsoft YaHei","Noto Sans CJK SC",sans-serif;background:#dce5df;color:var(--ink)}button,input,textarea{font:inherit}button{cursor:pointer;background:transparent;border:1px solid var(--line);border-radius:9px;color:inherit;padding:10px 16px;transition:background .18s}button:hover{background:var(--light)}button:disabled{opacity:.3;cursor:default}button:focus-visible,a:focus-visible,input:focus-visible,textarea:focus-visible{outline:3px solid #4f9b7d;outline-offset:3px}a{color:var(--green);text-underline-offset:4px}h2,p{margin:0}button.primary{background:var(--green);color:white;border-color:var(--green)}
#viewport{position:fixed;inset:0 0 var(--bar);display:grid;place-items:center;overflow:hidden}#stage{width:1280px;height:720px;position:absolute;transform-origin:center;box-shadow:var(--shadow);background:var(--paper)}
.slide{position:absolute;inset:0;background:var(--paper);display:none;overflow:hidden}.slide.active{display:block;animation:none}.slide.dark{background:var(--dark);color:white}.page-kicker{position:absolute;left:64px;top:35px;font-size:16px;line-height:28px;color:var(--muted)}.dark .page-kicker{color:var(--mint)}.page-title{position:absolute;left:64px;top:89px;width:1152px;height:104px;display:flex;align-items:center;font-size:42px;font-weight:650;line-height:1.25;letter-spacing:-.5px}.artboard{position:absolute;inset:0}.element{position:absolute}.text{display:flex;align-items:center;pointer-events:auto}.text-inner{width:100%;min-width:0}.text p{line-height:1.25;overflow-wrap:break-word;white-space:pre-wrap}.decoration{pointer-events:none}.page-footer{position:absolute;left:64px;right:64px;bottom:26px;display:flex;justify-content:space-between;font-size:13px;color:var(--muted);pointer-events:none}.dark .page-footer{color:#aac7ba}.table-wrap table{width:100%;height:100%;border-collapse:collapse;table-layout:fixed}.table-wrap td,.table-wrap th{border:1px solid var(--line);padding:12px 10px;text-align:left;vertical-align:middle}.table-wrap p{line-height:1.4;white-space:pre-wrap;overflow-wrap:break-word}.image-zoom{border:0;padding:0;border-radius:4px;overflow:hidden;cursor:zoom-in}.image-zoom img{width:100%;height:100%;object-fit:contain;display:block}.image-zoom:hover{box-shadow:0 0 0 3px #85b69f}.slide-action{position:absolute;right:64px;bottom:69px;background:var(--green);border-color:var(--green);color:white;font-size:16px;padding:8px 18px;z-index:2}.slide-action:hover{background:#1b493b}.practice-tools{position:absolute;left:68px;bottom:68px;display:flex;gap:10px}.dark .practice-tools button{color:var(--mint);border-color:#4a7762;font-size:15px}.dark .practice-tools button:hover{background:#254a3f}.prompt-copy{cursor:text}
#toolbar{position:fixed;inset:auto 0 0;height:var(--bar);z-index:20;display:flex;align-items:center;gap:10px;padding:0 24px;background:#ffffffed;border-top:1px solid #cad9ce;backdrop-filter:blur(20px);font-size:13px}#progress{position:absolute;top:-3px;left:0;height:3px;background:var(--green);transition:width .2s}#toolbar button{padding:8px 11px;white-space:nowrap}.brand{display:flex;gap:9px;align-items:center;font-weight:600;text-decoration:none;margin-right:25px;color:var(--ink)}.brand-mark{width:31px;height:31px;display:grid;place-items:center;background:var(--green);border-radius:9px;color:var(--mint);font-size:17px}.nav-group{display:flex;align-items:center;gap:8px}#page-label{font-variant-numeric:tabular-nums;min-width:62px;text-align:center}#hint{font-size:12px;color:var(--muted);margin-left:8px}.key{font-size:10px;color:var(--muted);margin-left:9px}.spacer{flex:1}#mini-timer{color:var(--green);font-weight:600;font-variant-numeric:tabular-nums}#reading-toggle[aria-pressed=true]{background:var(--green);color:white;border-color:var(--green)}
dialog{border:1px solid var(--line);border-radius:18px;padding:32px;background:var(--paper);color:var(--ink);width:min(1040px,94vw);max-height:88vh;box-shadow:var(--shadow)}dialog::backdrop{background:#0c251fcc;backdrop-filter:blur(7px)}dialog header{display:flex;justify-content:space-between;align-items:center;gap:20px;margin-bottom:24px}dialog header h2{font-size:26px;line-height:1.5}dialog header button{flex-shrink:0}dialog p{line-height:1.85;color:var(--muted);margin:12px 0}dialog .eyebrow{font-size:13px;color:var(--green);margin:0 0 5px}#toc-search{width:100%;border:1px solid var(--line);border-radius:10px;padding:13px 16px;background:white;margin-bottom:20px}#toc-list{display:grid;grid-template-columns:repeat(3,1fr);gap:10px}.toc-item{padding:16px;text-align:left;font-size:14px;line-height:1.65;display:flex;gap:12px;align-items:flex-start}.toc-item span{font-variant-numeric:tabular-nums;color:var(--green)}.toc-item.current{background:var(--light);border-color:var(--green);font-weight:600}.toc-item[hidden]{display:none}#notes-body{font-size:21px;line-height:1.95;white-space:pre-wrap}#material-list{display:grid;gap:10px;margin:20px 0}.material-item{display:flex;justify-content:space-between;align-items:center;padding:12px 16px;background:white;border:1px solid var(--line);border-radius:10px;gap:15px}.material-item span{line-height:1.7}.material-item small{display:block;color:var(--muted)}details{margin-top:24px;border-top:1px solid var(--line);padding-top:20px}summary{cursor:pointer;font-weight:600}#image-dialog{width:min(1400px,96vw)}#zoom-image{width:100%;height:68vh;object-fit:contain}#copy-text{width:100%;height:240px;resize:vertical;padding:18px;border:1px solid var(--line);border-radius:10px;line-height:1.8}#toast{position:fixed;left:50%;bottom:calc(var(--bar) + 18px);transform:translateX(-50%);padding:12px 22px;border-radius:10px;background:var(--green);color:white;opacity:0;transition:opacity .2s;pointer-events:none;z-index:100;max-width:90vw;font-size:15px}#toast.show{opacity:1}.checks{display:grid;gap:14px}.checks label{display:flex;gap:14px;align-items:center;background:white;border:1px solid var(--line);border-radius:10px;padding:16px;font-size:19px;cursor:pointer}.checks input{width:21px;height:21px;accent-color:var(--green)}.visually-hidden{position:absolute!important;width:1px!important;height:1px!important;padding:0!important;margin:-1px!important;overflow:hidden!important;clip:rect(0,0,0,0)!important;white-space:nowrap!important;border:0!important}.no-script{position:fixed;z-index:1000;padding:30px;background:white}
body.reading{overflow:auto;background:var(--paper)}.reading #viewport{position:static;display:block;overflow:visible;padding:30px 24px 100px}.reading #stage{position:static;width:min(1040px,100%);height:auto;transform:none!important;box-shadow:none;margin:auto;background:none}.reading .slide,.reading .slide.active{position:relative;display:block;height:auto;min-height:0;overflow:visible;padding:45px 48px;margin:20px 0 40px;background:white;border:1px solid var(--line);border-radius:20px;color:var(--ink);animation:none}.reading .page-kicker{position:static;color:var(--green);margin-bottom:12px}.reading .page-title,.reading .page-title.visually-hidden{position:static!important;width:auto!important;height:auto!important;clip:auto!important;overflow:visible!important;white-space:normal!important;margin:0 0 30px!important;font-size:32px;display:block}.reading .artboard{position:static;display:flex;flex-direction:column;gap:18px}.reading .element{position:static!important;width:auto!important;height:auto!important}.reading .decoration,.reading .text[data-role=number],.reading .page-footer{display:none}.reading .text span{font-size:21px!important;color:var(--ink)!important}.reading .text p{line-height:1.8}.reading .table-wrap{overflow-x:auto}.reading table{min-width:650px;height:auto}.reading table span{font-size:18px!important;color:var(--ink)!important}.reading th span{color:white!important}.reading td,.reading th{padding:16px}.reading .image-zoom{width:100%!important;aspect-ratio:16/9}.reading .slide-action,.reading .practice-tools{position:static;margin-top:24px}.reading .practice-tools button{color:var(--green);border-color:var(--line)}.reading .dark .practice-tools button:hover{background:var(--light)}.reading .prompt-copy{padding:20px;background:var(--light);border-radius:12px}.reading .brand{margin-right:10px}
@keyframes page-in{from{opacity:.4;transform:translateY(7px)}to{opacity:1;transform:none}}
@media(prefers-reduced-motion:reduce){*,*:before,*:after{animation:none!important;transition:none!important}}
@media(max-width:1100px){.brand span:last-child,#hint{display:none}.brand{margin-right:8px}.key{display:none}#toolbar{padding:0 16px}.toc-item{font-size:13px}}
@media(max-width:640px){:root{--bar:64px}.brand,.full-button{display:none}#toolbar{padding:0 8px;gap:5px}#toolbar button{font-size:12px;padding:9px 7px}.nav-group{gap:3px}#page-label{min-width:49px;font-size:12px}.spacer{min-width:0}#mini-timer{position:fixed;top:10px;right:10px;background:var(--mint);padding:5px 9px;border-radius:6px;font-size:12px}#mini-timer:empty{display:none}#toc-list{grid-template-columns:1fr}dialog{padding:23px;max-height:85vh}dialog header h2{font-size:21px}#notes-body{font-size:17px}.material-item{align-items:flex-start;font-size:14px;padding:12px}.material-item button{padding:8px}.reading #viewport{padding:5px 12px 75px}.reading .slide{padding:28px 22px;margin-bottom:20px}.reading .page-title{font-size:27px!important}.reading .text span{font-size:18px!important}.reading .practice-tools{flex-wrap:wrap}}
@media print{@page{size:13.333in 7.5in;margin:0}html,body,body.reading{height:auto;overflow:visible;background:white}#viewport,.reading #viewport{position:static;display:block;padding:0;overflow:visible}#stage,.reading #stage{position:static;width:1280px;max-width:none;height:auto;transform:none!important;box-shadow:none}body .slide,body .slide.active,body.reading .slide{display:block;position:relative;width:1280px;height:720px;min-height:720px;padding:0;margin:0;border:0;border-radius:0;overflow:hidden;break-after:page;page-break-after:always;print-color-adjust:exact;-webkit-print-color-adjust:exact}.slide:last-child{break-after:auto}#toolbar,dialog,#toast,.slide-action,.practice-tools,#live-status{display:none!important}.reading .artboard{position:absolute;inset:0;display:block}.reading .element{position:absolute!important}.reading .decoration{display:block}.reading .page-title{position:absolute!important;left:64px;top:89px;font-size:42px!important}.reading .page-kicker{position:absolute}.reading .text span{font-size:revert-layer!important}.reading .page-footer{display:flex}.reading .text[data-role=number]{display:flex}}
/* Series tokens and shared presentation patterns from the first lecture. */
:root{--ink:#f4f7ff;--green:#77ecd7;--mint:#77ecd7;--light:#182b44;--paper:#080f20;--muted:#a8b7ce;--line:#425771;--dark:#080f20;--bar:62px;--shadow:0 25px 90px #0008;--bg:#080f20;--panel:#101d35;--text:#f4f7ff;--cyan:#77ecd7;--purple:#aaa3ff;--coral:#ffad95}
body{background:#050913;color:var(--text)}
.slide,.slide.dark{background:radial-gradient(ellipse at 100% 0,rgba(76,79,159,.14),transparent 48%),var(--bg);color:var(--text)}
.slide:after{content:"";position:absolute;width:360px;height:360px;right:-240px;bottom:-240px;border:1px solid #7ef1da22;border-radius:50%;box-shadow:0 0 0 32px #7ef1da05,0 0 0 64px #7ef1da03;pointer-events:none}
.page-kicker,.dark .page-kicker{color:var(--cyan);font-size:14.4px;letter-spacing:1.6px;top:35px}.series-brand{position:absolute;right:64px;top:35px;height:28px;line-height:28px;color:var(--muted);font-size:14.4px;letter-spacing:1.6px}
.page-title{font-size:40.8px;letter-spacing:-.8px}.page-footer,.dark .page-footer{color:#8293ae;font-size:12.8px;letter-spacing:.8px}.page-footer>span:last-child{color:#c8d4e7}.foot-time{opacity:.85}
.slide-top{position:absolute;top:35px;left:64px;right:64px;display:flex;justify-content:space-between;color:var(--muted);font-size:14.4px;letter-spacing:1.6px}.section-name{color:var(--cyan)}
.title{position:absolute;top:89px;left:64px;width:1152px;height:104px;display:flex;align-items:center;font-size:40.8px;line-height:1.3;font-weight:650;margin:0;letter-spacing:-.8px}
.content{position:absolute;left:64px;right:64px;top:195px;bottom:74px;display:flex;flex-direction:column;justify-content:center;gap:22.4px;min-height:0}.content h1,.content h3{margin:0}.content h1{font-size:65.6px;line-height:1.3;font-weight:650;letter-spacing:-2.4px}.eyebrow{font-size:16.8px;letter-spacing:2.4px;color:var(--cyan);margin-bottom:20.8px}.slide-foot{position:absolute;left:64px;right:64px;bottom:26px;display:flex;justify-content:space-between;align-items:center;color:#8293ae;font-size:12.8px;letter-spacing:.8px}.slide-foot b{color:#c8d4e7;font-weight:450}
.cover .content{top:90px;bottom:70px}.cover .hero-copy{width:690px}.cover .hero-art{width:520px}.speaker .content{top:175px;bottom:75px}.agenda .content{top:190px;bottom:75px}.questions .content,.thanks .content{top:120px;bottom:80px}
button{background:rgba(141,169,215,.09)}button:hover{background:rgba(141,169,215,.2)}button:focus-visible,a:focus-visible,input:focus-visible,textarea:focus-visible{outline-color:var(--cyan)}button.primary,.slide-action{background:var(--cyan);border-color:var(--cyan);color:#08251f;font-weight:600}.slide-action:hover{background:#a7ffe9}.dark .practice-tools button{border-color:#425771;color:var(--cyan)}.dark .practice-tools button:hover{background:#182b44}
#toolbar{padding:0 22px;background:#0c1323;border-top-color:#26344d;backdrop-filter:none;gap:10px}#toolbar .brand{display:none}#toolbar button{font-size:13px;border-radius:6px;padding:7px 12px}#page-label{color:#ccdaeb}#hint{font-size:13px;color:#8ea1ba}#progress{background:linear-gradient(90deg,var(--cyan),var(--purple))}#mini-timer{color:var(--cyan)}#reading-toggle[aria-pressed=true]{background:#77ecd717;border-color:var(--cyan);color:var(--cyan)}.key{color:#8ea1ba}
dialog{background:#101c30;border-color:#425771;border-radius:16px;color:var(--text)}dialog::backdrop{background:#020611db}dialog p{color:#c0d0e5}dialog .eyebrow{color:var(--cyan)}#toc-search,#copy-text{background:#0c1628;color:var(--text);border-color:var(--line)}.toc-item.current{border-color:var(--cyan);background:#77ecd717}.toc-item span{color:var(--cyan)}.material-item,.checks label{background:#15243b;border-color:#425771}.checks input{accent-color:var(--cyan)}#toast{background:#e0fff5;color:#173c32}
.reading .slide,.reading .slide.active{background:#101d35;color:var(--text);border-color:#263b53}.reading .page-title,.reading .text span{color:var(--text)!important}.reading .page-kicker{color:var(--cyan)}.reading .slide:after{display:none}.reading .series-brand{display:none}.reading .slide-top{position:static;margin-bottom:18px}.reading .title{position:static;width:auto;height:auto;margin-bottom:25px;font-size:32px}.reading .content{position:static;display:flex;gap:20px}.reading .content h1{font-size:42px}.reading .slide-foot{display:none}.reading .cover .hero-copy,.reading .cover .hero-art,.reading .speaker .speaker-layout,.reading .speaker .speaker-figure{position:static;width:auto}.reading .cover .hero-art{max-width:450px}.reading .cover .hero-copy{width:100%}.reading .speaker .speaker-layout{grid-template-columns:1fr}.reading .speaker-photo{max-width:100%}.reading .agenda-list li{grid-template-columns:50px 1fr;gap:12px}.reading .agenda-list li p{grid-column:2}.reading .agenda-list h3{font-size:23px}.reading .agenda-list p{font-size:19px}.reading .agenda-goal{font-size:20px}.reading .thanks h1{font-size:100px}.reading .prompt-copy{background:#182b44}.reading th span{color:var(--text)!important}.reading .practice-tools button{color:var(--cyan)}
@media(max-width:1100px){#hint{display:none}}
@media(max-width:640px){#toolbar{padding:0 8px;gap:5px}#toolbar button{padding:8px 7px;font-size:12px}.reading .page-title,.reading .title{font-size:27px}.reading .content h1{font-size:34px}.reading .speaker-name{flex-wrap:wrap}.reading .hero-meta{flex-wrap:wrap}.reading .hero-sub{font-size:21px}.reading .series-brand{display:none}}
@media print{.slide,.slide.dark{print-color-adjust:exact;-webkit-print-color-adjust:exact}}
/* Keep table labels readable and the shared speaker layout within its frame. */
.table-wrap th{background:#193850!important}.table-wrap th span{color:var(--cyan)!important}
@media(min-width:641px){.speaker .speaker-layout{grid-template-columns:minmax(0,1fr) 320px}.speaker .speaker-photo{width:320px}}

/* Light presentation trial: keep the series layout and use dark foregrounds. */
:root{--ink:#1d3047;--green:#17675d;--mint:#d8eee5;--light:#eaf0f7;--paper:#f7f9fc;--muted:#526477;--line:#ced9e4;--dark:#f7f9fc;--bg:#f7f9fc;--panel:#ffffff;--text:#1d3047;--cyan:#17675d;--purple:#6652a6;--coral:#a64d2f;--shadow:0 22px 70px #243a501a}
body{background:#e6edf4;color:var(--text)}
.slide,.slide.dark{background:radial-gradient(ellipse at 100% 0,#edf0fa 0,transparent 52%),var(--bg);color:var(--text)}
.slide:after{border-color:#5b8ba625;box-shadow:0 0 0 32px #5b8ba608,0 0 0 64px #5b8ba604}
.page-footer,.dark .page-footer,.slide-foot{color:#607286}.page-footer>span:last-child,.slide-foot b{color:#40566e}
.cover .primary,.slide-action,button.primary{background:var(--cyan);border-color:var(--cyan);color:#fff}.cover .primary:hover,.slide-action:hover,button.primary:hover{background:#115248}
.cover .gradient,.questions .gradient,.thanks h1{background:linear-gradient(110deg,#17675d,#286d9e 50%,#6652a6);background-clip:text;-webkit-background-clip:text;-webkit-text-fill-color:transparent}
.table-wrap td{border-color:var(--line)}.table-wrap th{background:#dce8f3!important}.table-wrap th span{color:#243f5d!important}
button{background:#eaf0f799}button:hover{background:#dfe8f2}.dark .practice-tools button{color:var(--cyan);border-color:#afc6c9}.dark .practice-tools button:hover{background:#e3efed}
#toolbar{background:#f9fbff;border-top-color:#ced9e4}#page-label{color:#243f5d}#hint,.key{color:#526477}#reading-toggle[aria-pressed=true]{background:#deeee9;border-color:var(--cyan);color:var(--cyan)}
dialog{background:#f7f9fc;border-color:var(--line);color:var(--text)}dialog::backdrop{background:#23364f70}dialog p{color:#526477}#toc-search,#copy-text{background:#fff;color:var(--text);border-color:var(--line)}.material-item,.checks label{background:#fff;border-color:var(--line)}.toc-item.current{background:#deeee9;border-color:var(--cyan)}#toast{background:#17675d;color:#fff}
.reading .slide,.reading .slide.active{background:#fff;color:var(--text);border-color:var(--line)}.reading .page-title,.reading .text span{color:var(--text)!important}.reading .prompt-copy{background:#eaf0f7}.reading .table-wrap th span{color:#243f5d!important}
@media(max-width:640px){#mini-timer{background:#deeee9;color:#17675d}}

/* The principle diagram stacks into a reading flow on smaller screens. */
.reading [data-page="knowledge-retrieval-principle"] .principle-lane{grid-template-columns:1fr}
.reading [data-page="knowledge-retrieval-principle"] .principle-takeaway{flex-wrap:wrap}
@media(max-width:760px){.reading [data-page="knowledge-retrieval-principle"] .lane-flow{grid-template-columns:1fr}.reading [data-page="knowledge-retrieval-principle"] .flow-arrow{transform:rotate(90deg)}.reading [data-page="knowledge-retrieval-principle"] article{min-height:0}}

.reading [data-page="knowledge-retrieval-principle"] .rag-intro{position:static;display:flex;flex-wrap:wrap;gap:8px;margin:0 0 24px}