/* Purple / white / black field manual. Long reading stays on white. */
:root{--ink:#17131d;--muted:#625b6c;--accent:#7928ca;--accent-bright:#a54bff;--accent-deep:#57208e;--paper:#fff;--line:#e0dae6;--light:#f4edf9;--orange:#9a2dc3;--black:#121016;--purple:#7928ca;--card:#fff;--soft:#f7f5fa}
*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:24px}body{margin:0;background:var(--paper);color:var(--ink);font-family:-apple-system,BlinkMacSystemFont,"PingFang SC","Microsoft YaHei",sans-serif;line-height:1.85}::selection{color:#fff;background:var(--accent)}a{color:var(--accent-deep);text-underline-offset:5px}a:hover{color:var(--accent)}button,input,select,textarea{font:inherit}button,select{min-height:42px;border:1px solid var(--line);background:#fff;color:var(--ink);border-radius:4px;padding:8px 14px}button{cursor:pointer;transition:background-color .16s ease,border-color .16s ease,color .16s ease}button:hover{border-color:var(--accent);background:var(--light)}button:focus-visible,a:focus-visible,input:focus-visible,select:focus-visible,textarea:focus-visible,summary:focus-visible{outline:3px solid var(--accent-bright);outline-offset:4px}button:disabled{opacity:.42;cursor:default}button[aria-pressed="true"]{background:var(--accent);color:#fff;border-color:var(--accent)}h1,h2,h3,h4,p{margin-top:0}h1,h2,h3,h4{letter-spacing:-.025em}h2{font-size:clamp(27px,3vw,38px);line-height:1.3;font-weight:850;margin-bottom:0}h3{font-size:22px;line-height:1.45;font-weight:750}h4{font-size:17px;line-height:1.6;margin:20px 0 9px;font-weight:750}p{margin-bottom:16px}strong,b{font-weight:750}main{max-width:1200px;margin:auto;padding:0 36px}
/* Training-manual cover. */
.masthead{max-width:none;margin:auto;padding:21px max(30px,calc((100vw - 1128px)/2));display:flex;align-items:center;justify-content:space-between;gap:28px;background:var(--black);color:#fff;border-bottom:1px solid #37303f}.brand{display:block;flex:0 0 auto;font-size:19px;font-weight:850;color:#fff;text-decoration:none;line-height:1.4;letter-spacing:-.04em}.brand:hover{color:#fff}.brand span{display:block;margin-top:4px;font-size:9px;letter-spacing:1.9px;color:#c9b9d8;font-weight:600}nav{display:flex;align-items:center;gap:25px;font-size:13px;line-height:1.5;flex-wrap:wrap;justify-content:flex-end}nav a{color:#e7dfed;text-decoration:none;padding:7px 0;white-space:nowrap}nav a[aria-current="page"]{color:#fff;text-decoration:underline;text-decoration-color:#b76aff;text-decoration-thickness:2px;text-underline-offset:7px}nav a:hover{color:#c994ff}.intro{padding:60px 48px 50px;margin:0 -36px;position:relative;isolation:isolate;overflow:hidden;background:var(--black);color:#fff;border-bottom:9px solid var(--accent)}.intro:before{content:"";position:absolute;width:43%;right:0;top:0;bottom:0;z-index:-1;background:var(--accent);clip-path:polygon(88% 0,100% 0,100% 100%,12% 100%);opacity:.6}.intro:after{content:"";position:absolute;top:0;bottom:0;right:2%;width:5.5%;z-index:-1;background:#d6b2ff;transform:skewX(-19deg);opacity:.18}.eyebrow{color:var(--accent);font-size:11px;font-weight:800;letter-spacing:1.8px;line-height:1.6;margin-bottom:12px}.intro .eyebrow{color:#c991ff}.intro h1{font-size:clamp(39px,6vw,76px);line-height:1.18;letter-spacing:-.055em;margin-bottom:24px;font-weight:900;max-width:830px}.intro h1 em{font-style:normal;color:#c38aff}.lead{font-size:18px;line-height:1.85;color:#d4cadc;max-width:750px}.intro-links{display:flex;gap:27px;align-items:center;flex-wrap:wrap;margin-top:31px}.intro-links a{color:#fff;font-size:14px;font-weight:650;text-decoration:none}.primary{display:inline-flex;align-items:center;justify-content:space-between;gap:34px;padding:13px 21px;background:var(--accent);color:#fff;border-radius:2px;border:1px solid transparent}.primary:hover{background:#8c38df;color:#fff;border-color:#be83fc}.intro-note{font-size:12px;line-height:1.75;color:#c0b1ca;margin-top:24px;max-width:710px}
/* Readable white sections; the diagrams carry the color. */
.section{padding:58px 0;border-bottom:1px solid var(--line)}.section-head{display:flex;justify-content:space-between;align-items:flex-end;gap:24px;margin-bottom:27px}.section-head .eyebrow{margin-bottom:9px}.section-intro{color:var(--muted);font-size:16px;max-width:880px;margin:0 0 29px}.section-intro strong{color:var(--ink)}.source-link{font-size:13px;flex:0 0 auto}.small{font-size:12px;line-height:1.8;color:var(--muted)}
#mechanics{border-bottom:4px solid var(--black)}#mechanics>.section-head{padding-bottom:24px;border-bottom:1px solid var(--line)}#mechanics>p{max-width:920px}.mechanics-intro{font-size:18px;max-width:900px}.mechanics-note,.principle-note{padding:20px 24px;border-left:4px solid var(--accent);background:var(--light);margin:24px 0;font-size:15px}.mechanics-note p:last-child,.principle-note p:last-child{margin-bottom:0}.mechanics-block,.mechanic-block{margin-top:32px;padding-top:28px;border-top:1px solid var(--line)}.mechanics-block>h3,.mechanic-block>h3{margin-bottom:13px}[data-mechanics]{margin:24px 0;min-width:0}.mechanics-summary{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:22px;margin:26px 0}.mechanics-summary>*{min-width:0;padding-top:14px;border-top:3px solid var(--accent)}.mechanics-summary h3,.mechanics-summary h4{margin:0 0 9px;font-size:19px}.mechanics-summary p{font-size:14px;color:var(--muted)}.learning-route{display:flex;flex-wrap:wrap;align-items:center;gap:10px 22px;padding:17px 0;margin:22px 0 0;border-top:1px solid var(--line);border-bottom:1px solid var(--line);font-size:14px}.learning-route a{font-weight:700}
/* Video and chapter navigation. */
.cinema{background:var(--black);border-radius:4px;overflow:hidden;border-bottom:4px solid var(--accent)}video{width:100%;display:block;aspect-ratio:16/9;background:#121016}#live-caption{min-height:65px;padding:15px 24px;color:#fff;text-align:center;font-size:17px;line-height:1.7}.player-tools{display:flex;align-items:center;gap:12px 15px;flex-wrap:wrap;margin:18px 0 13px;font-size:13px}.player-tools label{display:flex;gap:8px;align-items:center}.player-tools a{margin-left:3px}.chapters{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:8px;margin:24px 0}.chapter{text-align:left;display:grid;grid-template-columns:43px 1fr;align-items:start;gap:9px;padding:13px 12px;font-size:13px;line-height:1.6;min-width:0}.chapter time{font-variant-numeric:tabular-nums;font-weight:700;color:var(--accent)}.chapter span{overflow-wrap:anywhere}.chapter.active,.chapter.active:hover{background:var(--accent);color:#fff;border-color:var(--accent)}.chapter.active time{color:#fff}details{border-top:1px solid var(--line);padding:17px 0}summary{cursor:pointer;font-weight:700;line-height:1.8}summary::marker{color:var(--accent)}#transcript-list{max-height:500px;overflow:auto;margin-top:16px;overscroll-behavior:contain}.utterance{display:block;width:100%;text-align:left;border:0;border-bottom:1px solid var(--line);border-radius:0;padding:15px 10px;background:transparent;line-height:1.75}.utterance time{font-size:12px;color:var(--accent);font-weight:700;margin-right:10px}.utterance .en{display:block;font-size:12px;color:var(--muted);margin:7px 0 0 48px}
/* Before the first climb. */
.basics{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:32px 45px}.basics article{position:relative;padding-left:45px}.number{position:absolute;left:0;top:2px;font-size:18px;line-height:1.3;font-weight:850;font-style:italic;color:var(--accent)}.basics h3{margin-bottom:10px}.basics p,.practice-grid p{font-size:15px}.safety{background:var(--black);color:#fff;border-left:5px solid var(--accent);padding:21px 25px;margin-top:32px}.safety strong{color:#dab5ff}.safety p{font-size:14px;margin:8px 0 0;color:#e6ddec}.glossary{margin-top:34px}.glossary h3{margin-bottom:19px}.glossary dl{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:21px 24px}.glossary dl>div{padding-top:13px;border-top:1px solid var(--line)}.glossary dt{font-size:14px;font-weight:800}.glossary dd{margin:5px 0 0;font-size:13px;color:var(--muted)}
/* Eight sequential lessons. */
.lesson{margin-top:48px;scroll-margin-top:24px;padding-top:32px;border-top:3px solid var(--black)}.lesson-heading{display:flex;align-items:center;gap:20px;margin-bottom:14px}.week-number{display:flex;align-items:center;justify-content:center;flex:0 0 57px;height:61px;background:var(--accent);color:#fff;clip-path:polygon(0 0,100% 0,100% 82%,82% 100%,0 100%);font-size:31px;line-height:1;font-style:italic;font-weight:850;font-variant-numeric:tabular-nums;padding-right:3px}.lesson h3{margin:0;font-size:clamp(22px,2.4vw,29px);font-weight:800}.en-title{font-size:12px;letter-spacing:.5px;color:var(--muted);margin-top:4px}.lesson-lead{font-size:19px;font-weight:650;line-height:1.7;margin:21px 0;color:var(--ink)}.lesson-top{display:grid;grid-template-columns:minmax(0,1.07fr) minmax(0,1fr);gap:31px;align-items:start;margin:25px 0}.lesson figure{margin:0;min-width:0}.lesson img{width:100%;border-radius:3px;aspect-ratio:16/9;object-fit:cover;background:var(--line)}figcaption{font-size:12px;color:var(--muted);margin-top:9px;line-height:1.7}.lesson-copy{font-size:15px;min-width:0}.lesson-copy h4{margin:0 0 10px;font-size:18px}.clip-card{position:relative;min-width:0}.clip-card .demo-clip{border-radius:3px;background:var(--black);border-bottom:3px solid var(--accent)}.clip-caption,.clip-note{font-size:12px;line-height:1.75;color:var(--muted);margin:9px 0 0}.clip-controls{display:flex;flex-wrap:wrap;align-items:center;gap:9px;margin-top:10px;font-size:12px}.clip-controls button{min-height:38px;padding:5px 12px;font-size:12px}
.lesson-reason{border-left:5px solid var(--accent);background:var(--light);padding:22px 26px;margin:25px 0}.lesson-reason h4,.lesson-reason h3{margin:0 0 10px;font-size:20px;font-weight:800}.lesson-reason p{font-size:15px;margin-bottom:12px}.lesson-reason p:last-child{margin-bottom:0}.lesson-reason strong{color:var(--accent-deep)}.lesson-reason ol,.lesson-reason ul{padding-left:22px;font-size:15px;margin:10px 0 0}.lesson-reason li{margin:7px 0}.cause-chain{display:flex;flex-wrap:wrap;gap:10px;align-items:center;margin:15px 0;font-size:14px;font-weight:700}.cause-chain span{padding:6px 10px;border:1px solid #d7c3e8;background:#fff;border-radius:3px}.cause-chain b,.cause-chain i{color:var(--accent);font-style:normal}
.animation-shell{padding:22px;background:#fff;border:1px solid var(--line);border-top:3px solid var(--accent);border-radius:3px;margin:26px 0}.animation-header{display:flex;justify-content:space-between;gap:16px;align-items:center;margin-bottom:18px;font-size:13px}.animation-header strong{font-size:17px;font-weight:800}.animation-header span{color:var(--muted);font-size:12px}.filmstrip{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:13px;margin-top:22px;padding-top:21px;border-top:1px solid var(--line)}.frame-step{min-width:0;margin:0;background:var(--soft);border-bottom:3px solid var(--line);padding:10px 10px 13px}.frame-step svg{display:block;width:100%;height:auto}.frame-step h4,.frame-step strong{display:block;font-size:14px;line-height:1.6;margin:8px 0 4px}.frame-step p,.frame-step figcaption{font-size:12px;line-height:1.75;margin:6px 0 0}.frame-step:last-child{border-bottom-color:var(--accent)}.filmstrip-title{font-size:14px;font-weight:750;margin:21px 0 8px}
.lesson-grid{display:grid;grid-template-columns:minmax(0,1.12fr) minmax(0,1fr);gap:34px;margin-top:29px}.lesson-grid>div>h4:first-child{margin-top:0}.lesson-grid ol{padding-left:23px;font-size:15px;margin:10px 0}.lesson-grid li{padding-left:5px;margin:10px 0}.lesson-grid li::marker{font-weight:800;color:var(--accent)}.lesson-grid p{font-size:15px}.mistakes{background:var(--soft);padding:21px 25px;border-radius:3px;border-top:3px solid var(--black)}.mistakes h4:first-child{margin-top:0}.mistakes p:last-child{margin-bottom:0}.drill{padding:22px 0;border-top:1px solid var(--line);border-bottom:1px solid var(--line);font-size:15px;margin-top:24px}.drill strong{color:var(--accent-deep)}.check{font-size:14px;color:var(--muted);margin-top:17px}.check b{color:var(--ink)}.jump-video{flex:0 0 auto;font-size:12px;padding:7px 11px;margin-left:auto;white-space:nowrap;min-height:38px}.lesson-source{font-size:12px;line-height:1.8;margin-top:18px;color:var(--muted)}
/* Existing SVG controls; their coordinates and colors remain owned by animations.js. */
.animation-shell .climb-anim{color:var(--ink)}.animation-shell .climb-anim .ca-stage{color:var(--accent-deep);font-size:16px;font-weight:800}.animation-shell .climb-anim .ca-svg{background:#faf8fc;border-radius:3px}.animation-shell .climb-anim .ca-controls button{border-radius:3px;border-color:#d5c4e3;color:var(--ink);min-height:40px}.animation-shell .climb-anim .ca-controls button:hover{background:var(--light);border-color:var(--accent)}.animation-shell .climb-anim .ca-controls .ca-play{background:var(--accent);color:#fff;border-color:var(--accent)}.animation-shell .climb-anim .ca-controls .ca-play:hover{background:var(--accent-deep)}.animation-shell .climb-anim .ca-detail{font-size:15px;line-height:1.8;color:var(--ink)}.animation-shell .climb-anim .ca-caption{color:var(--muted)}.animation-shell .climb-anim .ca-range{accent-color:var(--accent)}.animation-shell .climb-anim .ca-count{color:var(--muted);font-weight:700}
/* Practice and personal notes. */
.session-plan{background:var(--soft);padding:29px 32px;border:1px solid var(--line);border-top:4px solid var(--accent);border-radius:3px}.session-plan ol{padding:0;margin:0;list-style:none;counter-reset:session}.session-plan li{display:grid;grid-template-columns:150px 1fr;gap:22px;padding:15px 0;border-top:1px solid var(--line);font-size:14px}.session-plan li strong:before{counter-increment:session;content:counter(session) " / ";color:var(--accent);font-size:12px;margin-right:6px}.practice-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:39px;margin-top:33px}.subheading{margin-top:31px}.checklist{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:13px 25px;margin-bottom:29px}.checklist label{display:flex;gap:11px;align-items:flex-start;font-size:14px;cursor:pointer}.checklist input{flex:0 0 auto;margin:5px 0 0;accent-color:var(--accent);width:18px;height:18px}.reflection{margin:31px 0;padding:28px 31px;background:var(--light);border-top:4px solid var(--accent);border-radius:3px}.reflection h3{font-size:22px}.reflection p{font-size:14px}.reflection label{display:block;font-size:14px;font-weight:750;margin-top:18px}.reflection textarea{display:block;width:100%;min-height:87px;resize:vertical;font:inherit;font-weight:400;background:#fff;color:var(--ink);border:1px solid #d6c4e4;border-radius:3px;padding:12px;margin-top:8px;line-height:1.75}.reflection textarea::placeholder{color:#83788c}.reflection .small{font-size:12px;margin:19px 0 0}.faq p{font-size:14px}.sources ol{padding-left:23px;margin-top:24px}.sources li{padding:9px 0 11px;font-size:14px}.sources li::marker{color:var(--accent);font-size:12px}.sources li span{display:block;font-size:12px;color:var(--muted);margin-top:3px}.sources>.small{max-width:850px;margin-top:22px}footer{max-width:1200px;margin:auto;display:flex;align-items:center;justify-content:space-between;gap:16px;padding:31px 36px;font-size:13px;font-weight:700}footer span{color:var(--muted);font-weight:400}
@media(min-width:1440px){.intro{margin-top:22px}}
@media(max-width:900px){.masthead{padding:19px 27px}nav{gap:15px;font-size:12px}.brand span{font-size:8px;letter-spacing:1.1px}.intro{padding:49px 36px 43px}.intro:before{width:26%;opacity:.3}.section{padding:45px 0}.mechanics-summary{gap:15px}.filmstrip{grid-template-columns:1fr}.frame-step{display:grid;grid-template-columns:minmax(0,1fr)}.frame-step svg{width:min(100%,390px);margin-inline:auto}}
@media(max-width:740px){.masthead{padding:17px 20px;align-items:flex-start;flex-direction:column;gap:12px}.brand{font-size:17px}.brand span{display:none}nav{gap:5px 14px;max-width:none;line-height:1.4;justify-content:flex-start}nav a{padding:2px 0}main{padding:0 20px}.intro{margin:0 -20px;padding:41px 24px 35px;border-bottom-width:6px}.intro:before{width:25%;opacity:.22}.intro:after{display:none}.intro .eyebrow{font-size:10px;letter-spacing:1.3px}.intro h1{letter-spacing:-.045em;margin-bottom:20px}.lead{font-size:16px}.intro-links{gap:18px 23px;margin-top:26px}.intro-links a{font-size:13px}.intro-note{font-size:11px;margin-top:21px}.section{padding:36px 0}.section-head{align-items:flex-start;gap:16px;margin-bottom:23px}.section-intro{font-size:15px;line-height:1.85}.source-link{font-size:11px;max-width:76px}.mechanics-summary{grid-template-columns:1fr;gap:15px}.mechanics-summary p{margin-bottom:0}.mechanics-note,.principle-note{padding:17px 19px;font-size:14px}.chapters{grid-template-columns:repeat(2,minmax(0,1fr));gap:7px}.chapter{padding:10px 8px;font-size:12px;grid-template-columns:35px 1fr;gap:5px}.basics,.lesson-top,.lesson-grid,.practice-grid{grid-template-columns:1fr;gap:24px}.basics article{padding-left:37px}.basics h3{font-size:20px}.number{font-size:16px}.glossary dl{grid-template-columns:repeat(2,minmax(0,1fr));gap:17px}.safety{padding:19px 20px}.lesson{margin-top:38px;padding-top:25px}.lesson-heading{gap:13px;flex-wrap:wrap;align-items:flex-start}.week-number{flex-basis:47px;height:53px;font-size:26px}.lesson-heading>div{flex:1;min-width:190px}.lesson h3{font-size:23px}.en-title{font-size:11px}.jump-video{margin-left:60px;margin-top:-3px;min-height:36px;font-size:11px}.lesson-lead{font-size:17px}.lesson-top{margin-top:19px}.lesson-copy{font-size:15px}.lesson-reason{padding:18px 20px;margin:23px 0}.lesson-reason h4,.lesson-reason h3{font-size:19px}.lesson-reason p{font-size:14px}.animation-shell{padding:13px}.animation-header{flex-wrap:wrap;gap:5px 13px;margin-bottom:14px}.animation-header strong{font-size:16px}.animation-header span{font-size:11px}.filmstrip{gap:13px;margin-top:18px;padding-top:18px}.frame-step{padding:10px 8px}.animation-shell .climb-anim .ca-detail{font-size:14px}.animation-shell .climb-anim .ca-controls button{min-height:42px}.mistakes{padding:19px 21px}.checklist{grid-template-columns:1fr}.session-plan{padding:21px}.session-plan li{grid-template-columns:1fr;gap:4px}.reflection{padding:22px 21px}.reflection h3{font-size:20px}.reflection textarea{font-size:16px}#live-caption{font-size:14px;padding:12px 14px;min-height:60px}.player-tools{font-size:12px;gap:9px 11px}.player-tools button,.player-tools select{font-size:13px;min-height:40px;padding:7px 10px}.utterance .en{margin-left:0}footer{padding:27px 20px}footer span{display:none}}
@media(max-width:390px){.masthead{display:block;padding:16px 18px 13px}nav{justify-content:flex-start;max-width:none;margin-top:12px;gap:5px 17px;font-size:11px}main{padding-inline:17px}.intro{margin-inline:-17px;padding-inline:20px}.intro h1{font-size:38px}.intro-links{gap:17px}.intro-links a{font-size:12px}.primary{gap:24px;padding:11px 16px}h2{font-size:26px}.lesson h3{font-size:21px}.lesson-heading>div{min-width:170px}.chapter{grid-template-columns:1fr;gap:1px}.animation-shell{padding:10px}.lesson-reason{padding-inline:17px}.glossary dl{gap:15px 12px}.glossary dd{font-size:12px}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*,*:before,*:after{animation:none!important;transition:none!important}}
@media print{.masthead,video,.player-tools,.chapters,.transcript,nav,footer,.ca-controls,.ca-range,.clip-controls{display:none}body{background:#fff;color:#000;font-size:11pt}main{max-width:none;padding:0}.intro{margin:0;padding:15px 0;background:#fff;color:#000;border-bottom:2px solid #000}.intro:before,.intro:after{display:none}.intro h1{font-size:30pt}.intro h1 em,.intro .eyebrow,.lead,.intro-note{color:#000}.intro-links,.cinema{display:none}.section{padding:22px 0}.lesson{break-before:page}.animation-shell,.frame-step,.lesson-grid,.lesson-reason{break-inside:avoid}.filmstrip{grid-template-columns:repeat(3,minmax(0,1fr))}.safety{color:#000;background:#fff;border:1px solid #000}.safety p,.safety strong{color:#000}a{color:inherit}}

/* Integrated cause-and-effect lesson components. */
.mechanics-opening{max-width:960px;margin:0 0 28px}.mechanics-opening .lead{max-width:none;color:var(--ink);font-size:21px;line-height:1.8;font-weight:500}.mechanics-opening .lead strong{color:var(--accent-deep);font-weight:750}.mechanics-opening>p:not(.lead){font-size:15px;color:var(--muted);line-height:1.9}.learning-path{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:15px;margin:28px 0 38px}.learning-path a{display:flex;align-items:flex-start;gap:14px;text-decoration:none;color:var(--ink);background:var(--soft);border-top:3px solid var(--accent);padding:19px 18px 17px;line-height:1.55;transition:background-color .16s ease}.learning-path a:hover{background:var(--light)}.learning-path b{display:flex;align-items:center;justify-content:center;flex:0 0 29px;height:33px;color:var(--accent);font-size:26px;font-style:italic;font-weight:850;line-height:1}.learning-path span{font-size:16px;font-weight:750;min-width:0}.learning-path small{display:block;font-size:12px;font-weight:400;line-height:1.7;color:var(--muted);margin-top:3px}.learning-path br{display:none}
.principle{padding-top:31px;margin-top:36px;border-top:1px solid var(--line);scroll-margin-top:24px}.principle-heading{display:flex;align-items:flex-start;gap:16px;margin-bottom:15px}.principle-heading>span{flex:0 0 43px;font-size:30px;font-weight:850;font-style:italic;line-height:1.2;color:var(--accent);font-variant-numeric:tabular-nums}.principle-heading h3{font-size:26px;line-height:1.45;margin:0;font-weight:800}.principle>p{font-size:15px;max-width:950px}.principle .observe{max-width:none;border-left:4px solid var(--accent);background:var(--light);padding:17px 20px;margin:17px 0 0;font-size:14px;line-height:1.85}.observe strong{color:var(--accent-deep)}.mechanics-bottom{margin-top:35px;padding:24px 28px;background:var(--black);color:#fff;border-left:5px solid var(--accent)}.mechanics-bottom>strong{display:block;font-size:20px;font-weight:800;line-height:1.6;color:#e2c4ff}.mechanics-bottom p{font-size:15px;color:#e0d5e8;margin:10px 0 0}
.reason-problem{color:var(--ink);font-weight:550}.reason-chain{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:22px;counter-reset:reason;margin:20px 0 22px}.reason-chain>div{min-width:0;border-top:1px solid #d5c2e5;padding-top:13px;counter-increment:reason}.reason-chain>div>span{display:block;font-size:13px;line-height:1.6;color:var(--accent-deep);font-weight:800;margin-bottom:8px}.reason-chain>div>span:before{content:counter(reason) " / ";font-variant-numeric:tabular-nums;font-size:12px;margin-right:4px}.reason-chain>div>p{font-size:15px;line-height:1.85;margin:0}.reason-feel{border-top:1px solid #d5c2e5;padding-top:16px;margin-top:18px}.reason-feel>strong{display:block;font-size:14px;line-height:1.7;margin-bottom:5px}.reason-feel p{font-size:14px;line-height:1.85;margin:0}.lesson-reason .reason-boundary{font-size:12px;line-height:1.85;color:var(--muted);margin:15px 0 0}.storyboard-heading{font-size:19px;font-weight:800;margin:31px 0 12px}.storyboard-heading+.filmstrip{margin-top:0}.extra-move{margin:32px 0;padding-top:28px;border-top:3px solid var(--black)}.extra-move>h4{font-size:21px;font-weight:800;line-height:1.6;margin:0 0 19px}.extra-move .lesson-top{align-items:start;margin:19px 0 25px}.extra-move .lesson-copy .lesson-reason{padding:19px 21px;margin:0}.extra-move .lesson-reason h4{font-size:18px;line-height:1.5}.extra-move .reason-chain{grid-template-columns:1fr;gap:13px;margin:16px 0}.extra-move .reason-chain>div{padding-top:10px}.extra-move .reason-chain>div>span{margin-bottom:4px}.extra-move .reason-chain>div>p{font-size:14px}.extra-move .reason-feel{margin-top:13px;padding-top:13px}
.clip-label{display:flex;justify-content:space-between;align-items:center;flex-wrap:wrap;gap:4px 12px;padding:9px 12px;background:var(--black);color:#fff;border-left:4px solid var(--accent);font-size:11px;line-height:1.65}.clip-label span:first-child{font-weight:700;letter-spacing:.3px}.clip-label span:last-child{font-variant-numeric:tabular-nums;color:#d9b8f4}.clip-controls label{display:flex;align-items:center;gap:7px;font-size:12px;flex-wrap:wrap}.clip-controls select{min-height:38px;padding:5px 9px;font-size:12px;max-width:100%}.clip-card figcaption strong{font-weight:750;color:var(--ink)}
.understanding-check{padding:24px 26px;margin:29px 0;background:var(--soft);border:1px solid var(--line);border-top:3px solid var(--accent);border-radius:3px}.understanding-check h4{font-size:18px;font-weight:800;margin:0 0 10px}.understanding-check>p:not(.quiz-feedback){font-size:15px;margin:0 0 16px;line-height:1.85}.quiz-options{display:grid;grid-template-columns:1fr;gap:10px;counter-reset:answer}.quiz-options button{display:flex;gap:12px;align-items:flex-start;text-align:left;min-width:0;font-size:14px;line-height:1.75;padding:12px 14px;white-space:normal}.quiz-options button:before{counter-increment:answer;content:counter(answer,upper-alpha);flex:0 0 20px;line-height:1.75;font-weight:800;color:var(--accent)}.quiz-options button[aria-pressed="true"]:before{color:#fff}.quiz-feedback{font-size:14px;line-height:1.85;padding:15px 17px;margin:17px 0 0;background:var(--light);border-left:3px solid var(--accent);color:var(--ink)}.quiz-feedback:empty{display:none}
@media(max-width:900px){.learning-path{gap:11px}.learning-path a{padding:16px 13px;gap:9px}.learning-path span{font-size:14px}.learning-path b{flex-basis:23px;font-size:24px}.reason-chain{grid-template-columns:1fr;gap:15px}.reason-chain>div{padding-top:11px}.reason-chain>div>span{margin-bottom:5px}}
@media(max-width:740px){.mechanics-opening .lead{font-size:18px;line-height:1.85}.mechanics-opening>p:not(.lead){font-size:14px}.learning-path{grid-template-columns:1fr;gap:10px;margin:25px 0 31px}.learning-path a{padding:14px 16px;gap:14px}.learning-path span{font-size:15px}.learning-path b{flex-basis:25px;font-size:26px}.learning-path small{font-size:12px}.principle{padding-top:26px;margin-top:29px}.principle-heading{gap:12px}.principle-heading>span{font-size:25px;flex-basis:35px}.principle-heading h3{font-size:22px}.principle>p{font-size:14px}.principle .observe{padding:15px 17px;font-size:13px}.mechanics-bottom{padding:21px 21px;margin-top:28px}.mechanics-bottom>strong{font-size:18px}.mechanics-bottom p{font-size:14px}.reason-chain>div>p{font-size:14px}.reason-feel p{font-size:14px}.storyboard-heading{font-size:17px;line-height:1.7;margin-top:27px}.extra-move{padding-top:24px;margin-top:27px}.extra-move>h4{font-size:19px}.extra-move .lesson-copy .lesson-reason{padding:18px 19px}.understanding-check{padding:20px 19px}.understanding-check h4{font-size:17px;line-height:1.7}.quiz-options button{font-size:14px;padding:11px 12px;min-height:44px}.quiz-feedback{padding:13px 14px;font-size:14px}}
@media(max-width:390px){.mechanics-opening .lead{font-size:17px}.principle-heading h3{font-size:20px}.principle-heading>span{font-size:23px;flex-basis:31px}.reason-chain>div>p{font-size:14px}.understanding-check{padding:18px 16px}.quiz-options button{gap:9px;padding:11px 10px}.quiz-options button:before{flex-basis:16px}.clip-label{font-size:10px;padding:8px 10px}}
@media print{.learning-path,.clip-label,.clip-controls,.quiz-options{display:none}.mechanics-opening .lead,.mechanics-bottom>strong,.mechanics-bottom p{color:#000}.mechanics-bottom{background:#fff;border:1px solid #000}.principle,.reason-chain,.understanding-check{break-inside:avoid}.reason-chain{grid-template-columns:repeat(3,minmax(0,1fr))}.extra-move .reason-chain{grid-template-columns:1fr}.quiz-feedback:empty{display:none}}

/* Public edition: source video stays on its original platform. */
#player{width:100%;aspect-ratio:16/9;display:block;border:0;background:#121016}footer{gap:16px;flex-wrap:wrap}@media print{iframe,.clip-links,.gif-state{display:none}}

.page-share{display:flex;gap:12px;align-items:center;flex-wrap:wrap}.page-share button{font:inherit;color:inherit;background:none;border:0;padding:0;cursor:pointer;text-decoration:underline;text-underline-offset:4px}.page-share [role="status"]:empty{display:none}.page-share [role="status"]{display:inline;font-size:11px}

/* Local GIF cards keep the reader in the current lesson. */
.gif-stage{position:relative;display:block;width:100%;padding:0;border:0;border-radius:0;overflow:hidden;background:var(--black);color:#fff;cursor:pointer}
.gif-stage:disabled{cursor:default}
.gif-stage:hover{background:var(--black);color:#fff}
.gif-stage img{display:block;width:100%;height:auto;aspect-ratio:16/9;border-radius:0;object-fit:contain}
.gif-state{display:block;padding:10px 14px;min-height:42px;background:var(--black);color:#fff;text-align:left;font-size:12px;line-height:1.8}
.gif-stage:hover .gif-state{background:var(--accent-deep)}
.gif-stage:focus-visible{outline:3px solid #ce91ff;outline-offset:-4px}
.clip-links{display:flex;justify-content:space-between;flex-wrap:wrap;gap:8px 18px;padding:11px 14px;background:var(--soft);font-size:12px;line-height:1.8}
.clip-links a{color:var(--accent-deep);text-underline-offset:3px}
.source-clip figcaption{padding:4px 14px 12px}
.clip-credit{display:block;margin-top:6px;font-size:11px;color:var(--muted)}
@media print{.gif-state,.clip-links{display:none}}