:root{color-scheme:light;--navy:#061932;--navy2:#0b2948;--gold:#f4ad1a;--gold-ink:#93620b;--paper:#f5f7f8;--ink:#172027;--muted:#66737f;--line:#dde4e7;--blue:#265d92;--blue-soft:#f3f7fc;font-family:Inter,-apple-system,BlinkMacSystemFont,"PingFang SC","Microsoft YaHei",system-ui,sans-serif;color:var(--ink);background:var(--paper);font-synthesis:none}
*{box-sizing:border-box}body{margin:0;line-height:1.65}a{color:inherit;text-decoration:none}button{font:inherit;cursor:pointer}a,button{-webkit-tap-highlight-color:transparent}button:disabled{cursor:default;opacity:.4}a:focus-visible,button:focus-visible,summary:focus-visible{outline:3px solid #d79811;outline-offset:4px}button{touch-action:manipulation}svg.icon{display:inline-block;width:20px;height:20px;flex:none;vertical-align:-4px}button .icon{width:15px;height:15px}button[hidden],[hidden]{display:none!important}.skip-link{position:fixed;left:16px;top:-100px;background:white;z-index:100;padding:12px}.skip-link:focus{top:12px}
.site-header{background:white;border-bottom:1px solid var(--line);height:70px;position:relative;z-index:40}.header-inner{max-width:1240px;padding:0 28px;height:100%;margin:auto;display:flex;align-items:center;gap:28px}.brand{display:flex;align-items:center;gap:19px}.brand img{width:144px;height:36px;object-fit:contain}.brand span{font-size:15px;color:var(--navy2);border-left:1px solid var(--line);padding-left:18px;font-weight:600}.site-header nav{display:flex;align-items:center;gap:10px;margin-left:auto;font-size:14px;font-weight:600}.site-header nav a{padding:9px 14px;border-radius:6px}.site-header nav .nav-current{background:#fff3d7;box-shadow:inset 0 -2px var(--gold)}.site-header nav .icon{width:13px;height:13px;vertical-align:-2px}.preview-badge{font-size:12px;color:#6d7780;background:#f3f5f6;border:1px solid var(--line);border-radius:4px;padding:2px 7px;white-space:nowrap}
.home-main,.article-main{max-width:1240px;margin:auto;padding:0 28px}.home-hero{padding:42px 0 30px;display:flex;justify-content:space-between;align-items:flex-end;gap:32px}.eyebrow{font-size:14px;font-weight:650;color:var(--gold-ink);margin:0 0 10px}.home-hero h1{font-size:34px;letter-spacing:-.7px;line-height:1.45;color:var(--navy);margin:0 0 12px}.mobile-break{display:none}.hero-description{font-size:16px;margin:0;color:var(--muted)}.notice-link{font-size:13px;white-space:nowrap;color:var(--navy2);padding-bottom:3px}.notice-link .icon{height:14px;width:14px;vertical-align:-2px}.notice-link:hover{text-decoration:underline}
.reading-guide{display:flex;align-items:center;gap:28px;flex-wrap:wrap;padding:17px 22px;border:1px solid var(--line);background:white;border-radius:10px;font-size:13px;color:var(--muted)}.reading-guide .guide-heading{color:var(--navy);font-weight:700;padding-right:20px;border-right:1px solid var(--line)}.reading-guide b{color:#253645;margin-right:7px;font-weight:650}.legend-dot{display:inline-block;width:7px;height:7px;border-radius:50%;margin-right:8px;vertical-align:1px}.fact-dot{background:var(--blue)}.insight-dot{background:#778595}.example-dot{background:#d8991b}
.courses{margin-top:30px}.section-intro{display:flex;justify-content:space-between;gap:20px;align-items:center;margin-bottom:17px}.section-intro h2{font-size:21px;color:var(--navy);margin:0}.section-intro>span{font-size:13px;color:var(--muted)}.course-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:20px}.course-card{display:flex;flex-direction:column;padding:22px 23px 0;background:white;border:1px solid #d9e1e6;border-radius:12px;box-shadow:0 2px 5px #06193204;transition:box-shadow .18s,border-color .18s,transform .18s;overflow:hidden}.course-card:hover{border-color:#d5a34a;box-shadow:0 8px 22px #0619320c;transform:translateY(-3px)}.card-top{display:flex;align-items:center;justify-content:space-between;margin-bottom:15px}.course-icon{display:inline-flex;width:43px;height:43px;align-items:center;justify-content:center;border-radius:10px;background:#edf2f7;color:var(--navy2)}.course-icon .icon{width:25px;height:25px}.ai .course-icon,.lab .course-icon,.tech .course-icon{background:#fff3d9;color:#967020}.video-duration{font-size:12px;color:var(--muted);display:flex;align-items:center;gap:4px}.video-duration .icon{width:12px;height:12px}.course-card h2{font-size:23px;line-height:1.5;margin:0 0 9px;color:var(--navy);display:flex;align-items:center;justify-content:space-between}.course-card h2 .icon{width:17px;height:17px;color:#8a98a5}.course-card>p{margin:0;font-size:15px;color:#52616e;line-height:1.8;min-height:54px}.card-tags{display:flex;flex-wrap:wrap;gap:7px;margin:17px 0 19px}.card-tags span{font-size:12px;padding:2px 8px;background:#f4f6f8;border-radius:4px;color:#64727e}.card-bottom{margin: auto -23px 0;padding:12px 23px;border-top:1px solid #ebeff2;background:#fafbfc;display:flex;align-items:center;justify-content:space-between;font-size:14px;font-weight:650;color:var(--navy2)}.card-bottom .icon{width:18px;height:18px}.course-card:hover .card-bottom{background:#fff6e4}.home-help{display:flex;align-items:center;gap:14px;padding:20px 0 0;margin-top:10px;color:#52616e;font-size:14px}.home-help>.icon{color:var(--gold-ink);width:23px;height:23px}.home-help strong{font-weight:600;color:#435264}.home-help p{display:inline;margin-left:12px;font-size:13px}.site-footer{max-width:1184px;margin:38px auto 0;border-top:1px solid var(--line);display:flex;gap:22px;justify-content:space-between;padding:22px 0 30px;font-size:12px;color:#73808c}
.breadcrumbs{display:flex;align-items:center;gap:9px;padding-top:22px;font-size:13px;color:#79838d}.breadcrumbs .icon{width:12px;height:12px}.breadcrumbs a:hover{color:var(--navy)}.article-heading{padding:21px 0 28px}.article-category{display:flex;align-items:center;gap:11px;font-size:13px;color:var(--muted)}.article-category .course-icon{width:30px;height:30px;border-radius:7px}.article-category .icon{width:19px;height:19px}.article-heading h1{font-size:34px;color:var(--navy);margin:10px 0;line-height:1.45;letter-spacing:-.5px}.article-heading h1>span{font-weight:400;color:#687685;margin-left:15px;font-size:26px}.article-heading>p{font-size:16px;margin:0;color:#586674}.article-layout{display:grid;grid-template-columns:minmax(0,760px) minmax(310px,360px);gap:30px;align-items:start}.reading-column{min-width:0}.takeaway-card{border-radius:10px;border:1px solid #e4d5ae;background:#fffbf2;padding:21px 25px 17px}.takeaway-heading{font-size:16px;font-weight:700;color:var(--navy);display:flex;justify-content:space-between;align-items:center;margin-bottom:12px}.takeaway-heading>span{font-size:11px;font-weight:500;color:#917037;border:1px solid #e6d6b0;border-radius:4px;padding:0 6px}.takeaway-card ol{list-style:none;counter-reset:takeaway;margin:0;padding:0;display:grid;gap:8px;font-size:15px}.takeaway-card li{counter-increment:takeaway;display:flex;align-items:baseline;gap:10px;color:#495361}.takeaway-card li:before{content:counter(takeaway);font-size:12px;font-weight:700;flex:none;width:20px;height:20px;text-align:center;line-height:20px;background:#f9e9c4;border-radius:50%;color:#855e14}
.article-toolbar{display:flex;justify-content:space-between;align-items:center;gap:14px;padding:22px 0 13px}.view-tabs{display:flex;gap:4px;background:#e9edf0;border-radius:7px;padding:3px}.view-tabs button{font-size:13px;border:0;border-radius:5px;padding:7px 15px;color:#5d6974;background:transparent}.view-tabs .selected{background:white;color:var(--navy);box-shadow:0 1px 4px #06193212;font-weight:650}.keyword-toggle{border:0;background:transparent;font-size:12px;color:#7a6335;display:flex;gap:6px;align-items:center;padding:8px 0}.keyword-toggle:before{content:'✓';width:14px;height:14px;border:1px solid #d6b974;border-radius:3px;line-height:13px;text-align:center;background:#fff0c3;font-size:10px}.keyword-toggle[aria-pressed=false]:before{content:'';background:white;border-color:#acb5bd}.content-key{display:flex;gap:13px;align-items:center;margin-bottom:16px;font-size:11px;color:var(--muted)}.content-key>span:not(.key-note){display:flex;gap:5px;align-items:center}.content-key>span:not(.key-note):before{content:'';width:6px;height:6px;border-radius:50%;background:#818fa0}.content-key .key-fact:before{background:var(--blue)!important}.content-key .key-example:before{background:#cf9a25!important}.key-note{margin-left:auto;color:#828b95}
.article-body{background:white;padding:28px 30px 8px;border:1px solid var(--line);border-radius:10px}.opening-insight{font-size:17px;line-height:1.9;padding:0 0 23px;margin-bottom:26px;border-bottom:1px solid var(--line)}.opening-label{display:block;font-size:12px;color:#72808c;margin-bottom:9px}.opening-insight p{margin:0 0 9px}.opening-insight p:last-child{font-size:15px;color:var(--muted);margin:0}.opening-insight strong{font-weight:650;color:var(--navy)}.article-section{margin-bottom:34px;scroll-margin-top:22px}.article-section>h2{font-size:23px;line-height:1.5;font-weight:700;color:var(--navy);display:flex;align-items:baseline;gap:12px;margin:0 0 21px}.section-number{font-size:18px;color:#a27820;font-weight:650;flex:none}.content-panel{margin:0 0 20px;font-size:17px;line-height:1.95}.panel-label{display:flex;align-items:center;gap:7px;font-size:12px;font-weight:700;color:#425769;line-height:1.6;margin-bottom:10px}.label-icon .icon{height:15px;width:15px;vertical-align:-3px}.label-note{color:#84909b;font-size:11px;font-weight:400;margin-left:auto}.fact-panel{background:#f5f8fc;border:1px solid #dce5ef;border-left:3px solid #567ea3;border-radius:7px;padding:15px 18px}.fact-panel>.panel-label{color:#315979}.insight-panel{padding:3px 0 0}.insight-panel>.panel-label{color:#6f7b85}.insight-panel>.panel-label:after{content:'';height:1px;background:#ebedf0;flex:1;margin-left:7px}.example-panel{padding:17px 20px;background:#fffbf1;border:1px solid #ecdcb6;border-left:3px solid #d6a441;border-radius:7px}.example-panel>.panel-label{color:#967027}.example-panel .label-note{color:#9a845c}.example-panel h3{font-size:17px;font-weight:650;color:#5d4825;margin:3px 0 13px}.official-example-panel{padding:17px 20px;border:1px solid #dce5ef;border-radius:7px}.official-example-panel>.panel-label{color:#315979}.evidence-block{position:relative;border-radius:4px;padding:1px 6px;margin:0 -6px 7px;transition:background .15s,box-shadow .15s}.evidence-block:last-child{margin-bottom:0}.evidence-block p{margin:0 0 11px}.evidence-block p:last-child{margin-bottom:0}.evidence-block ul{margin:0 0 12px;padding-left:1.2em}.evidence-block ul:last-child{margin-bottom:0}.evidence-block li{margin:6px 0;padding-left:2px}.evidence-block li::marker{color:#96a5b5;font-size:.8em}.evidence-block strong{font-weight:650;color:#132e49}mark{background:linear-gradient(transparent 57%,#f8e2a4 57%);color:inherit;padding:0 .08em;font-weight:600;box-decoration-break:clone;-webkit-box-decoration-break:clone}.no-keywords mark{background:transparent;font-weight:inherit;padding:0}.source-actions{display:flex;flex-wrap:wrap;gap:7px;margin:10px 0 4px}.source-button{display:inline-flex;align-items:center;gap:6px;border:1px solid #cedce8;color:#315c80;background:#fff;border-radius:5px;padding:4px 9px;font-size:11px;line-height:1.7;transition:background .15s}.source-button:hover{background:#eaf2fc;border-color:#7d9fbe}.source-button .icon{width:12px;height:12px}.button-time{font-variant-numeric:tabular-nums;font-size:10px;color:#7a8997;border-left:1px solid #e0e5e8;padding-left:7px;margin-left:1px}.insight-panel .source-button{color:#66798a;border-color:#dce3e8;background:#fafbfc}.evidence-block.is-preview{background:#f7eccc;box-shadow:inset 3px 0 #e5c579}.evidence-block.is-active{background:#fff0be;box-shadow:inset 3px 0 #d9a12d}.source-button[aria-pressed=true]{background:#fff0c7;border-color:#d3a044;color:#765015}.source-button[aria-pressed=true] .button-time{color:#8b713c;border-left-color:#e8ce94}.evidence-block.is-active strong{color:#533f18}.evidence-block.is-active mark{background:none}
.sidebar-sticky{position:sticky;top:20px}.player-card{background:#fff;border:1px solid var(--line);border-radius:10px;overflow:hidden;box-shadow:0 3px 12px #06193205}.player-heading{display:flex;align-items:center;justify-content:space-between;padding:13px 16px;border-bottom:1px solid #e7ebef}.player-heading strong{font-size:14px;font-weight:650;color:var(--navy)}.player-heading strong .icon{width:15px;height:15px;margin-right:5px;vertical-align:-2px}.player-collapse{font-size:11px;background:none;border:0;color:#697886;padding:4px}.player-card video{width:100%;aspect-ratio:16/9;display:block;object-fit:contain;background:#101a27}.player-info{padding:11px 15px 6px}.player-info p{margin:0}.player-info #now-playing{font-size:13px;font-weight:650;color:var(--navy)}#player-context{font-size:11px;color:#798592;margin-top:4px;line-height:1.6}.player-controls{display:flex;gap:5px;padding:5px 11px 13px}.player-controls button{font-size:11px;border:1px solid #e0e6eb;background:#f8fafb;border-radius:4px;color:#506477;padding:5px 8px;flex:1;white-space:nowrap}.player-controls button:hover:not(:disabled){border-color:#b7c6d4;background:#eef3f8}#player-error{font-size:12px;color:#a34526;padding:0 15px 12px;margin:0}.desktop-toc{padding:23px 3px 4px}.toc-heading{display:flex;align-items:center;justify-content:space-between;font-size:13px;font-weight:700;color:var(--navy);margin-bottom:12px}.toc-heading>span{font-size:10px;font-weight:400;color:#7c8995}.desktop-toc a,.mobile-toc nav a{display:flex;align-items:baseline;gap:9px;font-size:13px;line-height:1.65;color:#657382;padding:9px 11px;border-left:2px solid #dde4e9}.desktop-toc a span,.mobile-toc nav a span{font-size:11px;color:#9aa5b0;flex:none}.desktop-toc a.is-current{background:#fff2d4;border-left-color:#dcaa3d;color:var(--navy);font-weight:600}.desktop-toc a:hover{background:#edf1f5;color:var(--navy)}.sidebar-back{display:block;font-size:12px;color:#7b8793;margin:15px 14px}.mobile-toc{display:none}.article-end{font-size:12px;color:#798590;margin:23px 0}.article-end p{margin-bottom:8px}.article-end a{color:#365d7e;margin-right:19px}.article-end a:hover{text-decoration:underline}.article-end .icon{width:12px;height:12px;vertical-align:-2px}.article-pager{border-top:1px solid var(--line);display:flex;justify-content:space-between;gap:14px;padding-top:20px;font-size:13px;color:var(--navy2)}.article-pager .icon{width:16px;height:16px;vertical-align:-3px}.article-pager a:hover{text-decoration:underline}.facts-only [data-role=insight],.facts-only [data-role=example]{display:none}.facts-only .article-section.no-facts{display:none}.facts-only .content-key{visibility:hidden}.facts-only .article-section{margin-bottom:27px}.player-card.is-expanded{position:fixed;z-index:100;inset:50%;transform:translate(-50%,-50%);width:min(1000px,94vw);max-height:94dvh;overflow:auto;box-shadow:0 0 0 100vmax #061932bd}.player-card.is-expanded video{max-height:70dvh}.player-card.is-expanded .player-heading{padding:13px 20px}.player-card.is-expanded #expand-video{background:#fff0c7}.player-card.is-expanded .player-collapse{display:none}
.reading-sidebar{align-self:stretch}.desktop-toc{max-height:calc(100dvh - 410px);overflow-y:auto;overscroll-behavior:contain}
@media(min-width:1400px){.home-main,.article-main{max-width:1320px}.header-inner{max-width:1320px}.article-layout{grid-template-columns:minmax(0,810px) minmax(340px,390px);gap:40px}.site-footer{max-width:1264px}.home-hero h1{font-size:37px}.course-card{padding-top:25px}}
@media(max-width:1040px){.brand span{display:none}.article-layout{grid-template-columns:minmax(0,1fr) 310px;gap:24px}.article-body{padding:24px 21px 6px}.home-hero h1{font-size:29px}.reading-guide{gap:15px}.reading-guide .guide-heading{padding-right:15px}.course-card{padding:19px 18px 0}.card-bottom{margin-left:-18px;margin-right:-18px;padding-left:18px;padding-right:18px}.course-card h2{font-size:21px}.card-tags{gap:5px}.card-tags span{font-size:11px;padding:2px 6px}.home-help p{display:block;margin:3px 0 0}.key-note{display:none}.label-note{font-size:10px}}
@media(max-width:820px){.site-header{height:62px}.header-inner{padding:0 20px;gap:14px}.brand img{width:125px}.site-header nav{font-size:12px;gap:2px}.site-header nav a{padding:8px 9px}.preview-badge{font-size:10px;padding:2px 5px}.home-main,.article-main{padding:0 20px}.home-hero{padding:29px 0 25px;display:block}.home-hero h1{font-size:29px}.notice-link{display:inline-block;margin-top:16px}.reading-guide{padding:15px 17px;gap:12px 20px}.reading-guide .guide-heading{flex-basis:100%;border:0;padding:0}.section-intro>span{display:none}.course-grid{grid-template-columns:repeat(2,minmax(0,1fr));gap:16px}.article-layout{display:flex;flex-direction:column;gap:0}.reading-column{width:100%}.reading-sidebar{width:100%;order:-1;position:sticky;top:0;z-index:30;background:var(--paper);padding:0 0 15px;margin-bottom:5px}.sidebar-sticky{position:static}.desktop-toc,.sidebar-back{display:none}.player-card{border-radius:8px}.player-card video{max-height:29dvh;aspect-ratio:16/9;background:#0e1825}.player-heading{padding:8px 14px}.player-heading strong{font-size:12px}.player-info{padding:8px 13px 3px}.player-controls{padding:4px 11px 9px;gap:7px}.player-info #now-playing{font-size:12px}#player-context{font-size:10px}.player-card:not(.is-expanded) #player-content{display:grid;grid-template-columns:1fr 1fr}.player-card:not(.is-expanded) video{grid-column:1/-1}.player-card:not(.is-expanded) .player-info{align-self:center}.player-card:not(.is-expanded) #player-context{display:none}.player-card:not(.is-expanded) .player-controls{align-self:center;padding-top:7px}.player-card:not(.is-expanded) #player-error{grid-column:1/-1}.mobile-toc{display:block;margin-bottom:17px;border:1px solid var(--line);border-radius:6px;background:white}.mobile-toc summary{cursor:pointer;font-size:13px;padding:10px 14px;color:var(--navy)}.mobile-toc nav{padding:0 14px 14px}.article-heading{padding:17px 0 21px}.article-heading h1{font-size:30px}.article-heading h1>span{font-size:23px}.article-heading>p{font-size:15px}.article-section{scroll-margin-top:calc(29dvh + 125px)}.article-section>h2{font-size:23px}.content-panel{font-size:17px}.site-footer{margin:30px 20px 0;padding-top:19px;display:block}.site-footer span{display:block;margin-bottom:5px}.takeaway-card{padding:18px 22px}.article-body{padding:26px 25px 5px}.player-card.is-expanded{width:95vw}.player-card.is-expanded video{max-height:64dvh}.player-collapsed .article-section{scroll-margin-top:68px}}
@media(max-width:520px){.header-inner{padding:0 16px;gap:8px}.brand img{width:112px}.site-header nav a{padding:8px}.site-header nav a:last-child{display:none}.preview-badge{margin-left:3px}.home-main,.article-main{padding:0 16px}.home-hero h1{font-size:27px;letter-spacing:-.5px;line-height:1.5}.mobile-break{display:block}.hero-description{font-size:14px;line-height:1.8}.home-hero{padding-top:26px}.reading-guide{font-size:12px;gap:10px}.reading-guide>span{flex-basis:100%}.reading-guide b{display:inline-block;width:62px;margin-right:5px}.courses{margin-top:25px}.section-intro h2{font-size:19px}.course-grid{grid-template-columns:1fr;gap:15px}.course-card{padding:18px 20px 0}.card-top{margin-bottom:10px}.course-icon{height:37px;width:37px;border-radius:8px}.course-icon .icon{width:23px;height:23px}.course-card h2{font-size:22px}.course-card>p{min-height:0;font-size:15px}.card-tags{margin:13px 0 16px}.card-tags span{font-size:11px}.card-bottom{margin-left:-20px;margin-right:-20px;padding:11px 20px}.home-help{align-items:flex-start;padding-top:15px}.home-help strong{font-size:13px}.home-help p{font-size:12px}.breadcrumbs{padding-top:17px;font-size:12px}.article-category{font-size:11px}.article-heading h1{font-size:27px}.article-heading h1>span{font-size:19px;margin-left:9px}.article-heading>p{font-size:14px;line-height:1.75}.article-body{padding:21px 18px 4px}.takeaway-card{padding:16px 18px}.takeaway-heading{font-size:14px}.takeaway-card ol{font-size:13px;gap:9px}.view-tabs button{font-size:12px;padding:7px 10px}.keyword-toggle{font-size:11px}.article-toolbar{gap:8px;padding-top:18px}.content-key{font-size:10px;gap:12px}.article-section>h2{font-size:21px;gap:9px;margin-bottom:16px}.section-number{font-size:16px}.fact-panel,.example-panel,.official-example-panel{padding:13px 13px}.content-panel{font-size:16px;line-height:1.9;margin-bottom:18px}.label-note{font-size:9px}.panel-label{font-size:11px}.opening-insight{font-size:16px}.opening-insight p:last-child{font-size:14px}.example-panel h3{font-size:16px}.source-button{font-size:10px;padding:4px 7px}.player-controls button{padding:5px 4px;font-size:10px}.player-info #now-playing{font-size:10px}.player-card:not(.is-expanded) #player-content{grid-template-columns:1fr 1.1fr}.reading-sidebar{padding-bottom:12px}.article-pager{font-size:12px}.article-end{font-size:11px}}
@media(prefers-reduced-motion:reduce){*{transition:none!important;scroll-behavior:auto!important}}
@media print{.site-header,.reading-sidebar,.source-actions,.article-toolbar,.mobile-toc,.article-pager,.preview-badge{display:none}.article-layout{display:block}.article-body{border:0;padding:0}.content-panel{break-inside:avoid}body{background:white}.article-section{break-before:auto}.article-main{max-width:100%}}

.article-section{scroll-margin-top:var(--reading-offset,22px)}

/* Reading revision: one continuous article; decoration never defines its outline. */
.article-page{background:#fff}.article-page .site-header{background:#fff}.article-main{max-width:1200px}
.reading-hint{font-size:12px;color:#818992}
.article-heading{padding:16px 0 19px}.article-heading h1{margin:7px 0}.article-heading>p{font-size:15px}
.article-layout{grid-template-columns:minmax(0,750px) minmax(310px,350px);gap:38px}
.article-toolbar{padding:0 0 15px;border-bottom:1px solid var(--line);margin-bottom:18px}.view-tabs{background:transparent;padding:0;gap:17px}.view-tabs button{background:none;padding:4px 0;border-radius:0;font-size:12px}.view-tabs .selected{box-shadow:none;border-bottom:2px solid #d6a33b;background:transparent}.keyword-toggle{padding:2px 0}
.article-body{padding:0;border:0;border-radius:0;background:none;font-size:17px;line-height:1.8}
.opening-insight{padding:0;margin:0 0 24px;border:0;font-size:17px;line-height:1.8}.opening-insight p{margin:0 0 8px}.opening-insight p:last-child{font-size:16px;color:#52606c}
.article-section{margin:0 0 28px}.article-section>h2{font-size:23px;margin:0 0 12px;gap:0;line-height:1.5}.section-number{font-size:inherit;font-weight:inherit;color:inherit}
.article-section p{margin:0 0 10px}.article-section ul{margin:5px 0 13px;padding-left:1.45em}.article-section li{padding-left:2px;margin:3px 0;line-height:1.8}.article-section li::marker{color:#6e7882;font-size:.8em}.article-section strong{color:#142c43;font-weight:650}
.source-unit{display:inline;position:relative;border-radius:0;padding:0;margin:0;cursor:default}.source-text{text-decoration:underline dotted #bfc8cf;text-underline-offset:5px;text-decoration-thickness:1px;box-decoration-break:clone;-webkit-box-decoration-break:clone;transition:background .12s}
.source-unit.is-preview>.source-text,.source-unit.is-active>.source-text{background:#ffedb0;text-decoration-color:transparent;box-shadow:none;border:0;border-radius:0;outline:0}.source-unit.is-preview,.source-unit.is-active{background:transparent;box-shadow:none;border:0}.source-unit:focus-visible{outline:none}.source-unit:focus-visible>.source-text{text-decoration:underline solid #c29a40;text-underline-offset:5px}.source-unit.is-active mark,.source-unit.is-preview mark{background:none}
.source-actions{position:fixed;z-index:80;display:flex;flex-wrap:wrap;max-width:calc(100vw - 16px);width:max-content;gap:5px;margin:0;padding:0;visibility:hidden;opacity:0;pointer-events:none}.source-unit.is-target>.source-actions{visibility:visible;opacity:1;pointer-events:auto}.source-actions:after{content:'';position:absolute;top:100%;left:-5px;right:-5px;height:9px}.source-actions.is-below:after{top:auto;bottom:100%}
.source-button{background:#fff;border:1px solid #d4dce3;box-shadow:0 3px 10px #06193216;border-radius:5px;padding:5px 9px;font-size:12px;line-height:1.6}.source-button .button-time{font-size:11px}.source-button[aria-pressed=true]{background:#fff5d9;border-color:#d9be7d}
.reading-sidebar{background:none}.sidebar-sticky{top:18px}.player-card{box-shadow:none}.desktop-toc{padding-top:20px}.desktop-toc a{font-size:12px;padding:7px 10px}.desktop-toc a.is-current{background:#fff9e9}.article-end{border-top:1px solid var(--line);padding-top:14px;margin:18px 0}.article-pager{border-top:0;padding-top:6px}
@media(max-width:1040px){.article-layout{grid-template-columns:minmax(0,1fr) 300px;gap:28px}}
@media(max-width:820px){.article-layout{display:flex;gap:0}.article-body{padding:0}.reading-sidebar{background:#fff}.article-section>h2{font-size:22px}.article-toolbar{margin-bottom:15px}.article-section{margin-bottom:25px}.mobile-toc{margin-bottom:18px;border:0;border-top:1px solid var(--line);border-bottom:1px solid var(--line);border-radius:0}.mobile-toc summary{padding-left:0}.article-heading{padding-bottom:18px}}
@media(max-width:520px){.article-body,.opening-insight{font-size:16px;line-height:1.8}.opening-insight p:last-child{font-size:15px}.article-section>h2{font-size:21px}.article-section p{margin-bottom:9px}.article-section ul{margin-top:4px;margin-bottom:12px}.article-section li{margin:3px 0}.article-heading h1{font-size:26px}.article-heading h1>span{font-size:18px}.source-button{font-size:11px}}

/* Compact article heading and direct, inline listening interaction. */
.article-heading{display:flex;align-items:baseline;justify-content:space-between;gap:16px;padding:14px 0 18px}
.article-heading h1{font-size:27px;line-height:1.4;margin:0;letter-spacing:0}
.article-heading h1>span{font-size:18px;margin-left:12px;color:#73808c}
.back-to-courses,.page-up-link{display:inline-flex;align-items:center;width:max-content;min-height:34px;padding:6px 12px;border:1px solid #cbd7e0;border-radius:6px;background:#f5f8fa;color:#173c5c;font-size:13px;font-weight:650;line-height:1.5;white-space:nowrap}.back-to-courses:hover,.page-up-link:hover{border-color:#d2a13c;background:#fff5dc;color:var(--navy)}
.page-up-link{margin-top:20px}
.opening-insight{margin-bottom:20px}.opening-insight p:last-child{font-size:inherit;color:inherit}
.source-unit{cursor:pointer;touch-action:manipulation}.source-text{cursor:inherit}
#source-hint{position:fixed;z-index:50;pointer-events:none;white-space:nowrap;font-size:11px;line-height:1.5;color:#85909a;font-weight:400}
.player-heading{position:relative}.player-info{padding-top:9px;padding-bottom:4px}.player-info p{margin:0}#player-context{margin-top:3px}
@media(max-width:820px){
 .article-heading{padding:11px 0 13px;gap:10px}.article-heading h1{font-size:25px}.article-heading h1>span{font-size:17px;margin-left:9px}
 .reading-sidebar{padding-bottom:12px;margin-bottom:3px}.player-card{overflow:visible}.player-heading{padding:6px 11px}
 .player-heading .mobile-toc{display:block;position:static;margin:0 10px 0 auto;padding:0;border:0;background:none}
 .mobile-toc summary{font-size:11px;padding:2px 4px;color:#73808c}.mobile-toc nav{position:absolute;top:100%;right:0;z-index:45;width:min(370px,calc(100vw - 32px));max-height:48dvh;overflow-y:auto;padding:10px 12px;background:#fff;border:1px solid var(--line);border-radius:5px;box-shadow:0 6px 18px #06193212}
 .player-card:not(.is-expanded) .player-info{padding:4px 11px}.player-card:not(.is-expanded) .player-controls{padding:5px 8px;gap:5px}.player-controls button{padding:3px 5px}
 .player-card.is-expanded{overflow:auto}
}
@media(max-width:520px){
 .article-heading h1{font-size:23px}.article-heading h1>span{font-size:15px;margin-left:7px}.back-to-courses{font-size:11px}
 .article-heading{gap:8px}.player-heading strong{font-size:11px}.player-controls button{font-size:10px;padding:3px}
}

/* Subheadings belong to the article hierarchy, with no surrounding panels. */
.article-section h3{font-size:18px;line-height:1.6;color:var(--navy2);font-weight:650;margin:19px 0 8px;letter-spacing:0}
.article-section h3:first-child{margin-top:0}
@media(max-width:520px){.article-section h3{font-size:17px;margin-top:17px;margin-bottom:7px}}

/* Subject article hierarchy: copy belongs visibly beneath each subheading. */
.article-body .article-section h3~p,
.article-body .article-section h3~ul,
.article-body .article-section h3~.training-case{margin-left:22px}
.article-body .article-section h3~ul{padding-left:1.45em}
@media(max-width:520px){
 .article-body .article-section h3~p,
 .article-body .article-section h3~ul,
 .article-body .article-section h3~.training-case{margin-left:14px}
 .article-body .article-section h3~ul{padding-left:1.35em}
}

/* Training text remains the main article; editorial material is clearly inset. */
.article-body{font-size:17px;line-height:1.65}
.article-section{margin-bottom:20px}.article-section>h2{font-size:22px;line-height:1.4;margin-bottom:9px}
.article-section p{margin:0 0 6px}.article-section ul{margin:3px 0 8px;padding-left:1.3em}.article-section li{margin:1px 0;line-height:1.65}
.article-section h3{font-size:17px;line-height:1.45;margin:12px 0 6px}
.training-passage{margin:0 0 10px}.training-label{font-size:11px;color:#52687d;font-weight:650;letter-spacing:.04em;margin:0 0 5px}
.interpretation-card{background:#f1f5f9;border:1px solid #d8e2ec;border-left:3px solid #809ab3;border-radius:5px;padding:10px 13px;margin:9px 0 11px;color:#425468;font-size:15px;line-height:1.6}
.interpretation-label{display:flex;align-items:center;gap:10px;font-size:11px;line-height:1.4;margin-bottom:6px;color:#526d88}.interpretation-label strong{font-size:11px;color:#385571;font-weight:650}.interpretation-label span{color:#8594a2;font-size:10px}
.interpretation-card h3{font-size:16px;color:#264763;margin:11px 0 5px;line-height:1.45}.interpretation-label+h3{margin-top:0}
.interpretation-card p{margin:0 0 5px}.interpretation-card ul{margin:3px 0 6px}.interpretation-card li{margin:0;line-height:1.6}
.interpretation-card strong{color:#29445e}.interpretation-card>:last-child{margin-bottom:0}
.opening-insight{padding:9px 13px;margin:0 0 16px;font-size:15px;line-height:1.6}.opening-insight p:last-child{font-size:inherit;color:inherit}
@media(max-width:520px){.article-body{font-size:16px;line-height:1.65}.article-section>h2{font-size:21px}.article-section p{margin-bottom:6px}.article-section ul{margin:3px 0 8px}.article-section li{margin:1px 0}.interpretation-card{padding:9px 11px;font-size:15px;margin:8px 0 10px}.interpretation-card li{margin:0}.interpretation-card h3{font-size:16px;margin-top:10px}.interpretation-label+h3{margin-top:0}}

/* Official cases sit inside the article; requirements remain plain paragraphs. */
.article-section .training-case{background:#f4f7fa;border:1px solid #dbe4ec;border-left:3px solid #8ba7c0;border-radius:5px;margin:9px 24px;padding:9px 12px;color:#33485b;font-size:15px;line-height:1.65}
.training-case-label{font-size:11px;line-height:1.4;font-weight:650;color:#637d94;letter-spacing:.04em;margin:0 0 4px}
.article-section .training-case h3{font-size:16px;line-height:1.45;font-weight:650;margin:0 0 5px;color:#163752}
.article-section .training-case p{margin:0;line-height:1.65}
.training-case .source-text{text-decoration-color:#aebecb}
@media(max-width:520px){.article-section .training-case{padding:8px 10px;margin:8px 12px}.article-section .training-case h3{font-size:16px}}

/* Desktop: video and navigation on the left; continuous article on the right. */
@media(min-width:821px){
 .article-layout{grid-template-columns:minmax(310px,350px) minmax(0,750px);grid-template-areas:"sidebar article";gap:38px}
 .reading-sidebar{grid-area:sidebar}.reading-column{grid-area:article}
}
@media(min-width:821px) and (max-width:1040px){.article-layout{grid-template-columns:300px minmax(0,1fr);gap:28px}}

/* A visible official-platform exit on the homepage and every article. */
.site-header nav a.official-platform-link{display:inline-flex;align-items:center;gap:6px;background:var(--navy2);color:#fff;border:1px solid var(--navy2);white-space:nowrap}
.site-header nav a.official-platform-link:hover{background:#17466c;border-color:#17466c}
@media(max-width:820px){.header-inner{gap:14px}.preview-badge{display:none}.site-header nav{gap:5px}.site-header nav .nav-current{display:none}.site-header nav .service-center-link{display:inline-flex;align-items:center;gap:5px;white-space:nowrap}}
@media(max-width:520px){.site-header nav a.official-platform-link{display:inline-flex;padding:7px 9px;gap:4px;font-size:12px}.site-header nav a.official-platform-link .icon{width:12px;height:12px}}

/* Course-specific official video, always beside the local player heading. */
.player-heading{gap:8px;flex-wrap:wrap}
.official-video-link{display:inline-flex;align-items:center;gap:4px;margin-left:auto;padding:3px 6px;border:1px solid #d7e2ed;border-radius:4px;background:#f1f6fa;color:#265d92;font-size:11px;line-height:1.5;white-space:nowrap}
.official-video-link .icon{width:12px;height:12px;vertical-align:middle}
.official-video-link:hover{background:#e4eef7;border-color:#9eb8cf}
@media(max-width:820px){.player-heading{gap:5px}.official-video-link{font-size:10px;padding:2px 4px}.player-heading .mobile-toc{margin:0 3px 0 0}}

.platform-training-entry{display:flex;align-items:center;gap:18px;margin-top:20px;padding:18px 22px;border:1px solid #cbd9e5;border-radius:9px;background:#f1f6fa;color:var(--navy2)}
.platform-training-entry:hover{border-color:#a9bdcd;background:#e9f1f7}
.platform-training-entry h2{font-size:19px;margin:0 0 4px}.platform-training-entry p{font-size:14px;margin:0;color:#52616e}.platform-entry-action{font-size:13px;font-weight:650;margin-left:auto;white-space:nowrap}.platform-entry-action .icon{width:16px;height:16px}
.sidebar-platform{display:block;padding:9px 12px;margin-top:14px;background:#f1f6fa;border:1px solid #d7e2ed;border-radius:5px;font-size:12px;color:#265d92}.sidebar-platform .icon{width:13px;height:13px}.sidebar-platform:hover{background:#e4eef7}
@media(max-width:820px){.sidebar-platform{display:none}}
@media(max-width:520px){.platform-training-entry{flex-wrap:wrap;gap:10px;padding:16px}.platform-training-entry>div{flex:1;min-width:0}.platform-training-entry p{font-size:13px}.platform-entry-action{width:100%;margin-left:0;padding-top:6px}.platform-training-entry h2{font-size:18px}}

/* Desktop reading width: a larger video by default, with a draggable divider. */
@media(min-width:821px){
 .article-main{max-width:1360px}
 .article-layout{--sidebar-width:min(calc(70% - 27px),calc(97.778dvh + 2px));grid-template-columns:var(--sidebar-width) 18px minmax(0,1fr);grid-template-areas:"sidebar resizer article";gap:18px}
 .layout-resizer{grid-area:resizer;position:relative;align-self:stretch;min-height:260px;cursor:col-resize;touch-action:none;outline:0}
 .layout-resizer:before{content:"";position:absolute;top:0;bottom:0;left:50%;width:1px;background:#dce3e8;transform:translateX(-50%);transition:background .15s,box-shadow .15s}
 .layout-resizer span{position:sticky;top:44vh;z-index:2;display:flex;align-items:center;justify-content:center;width:18px;height:34px;border:1px solid #cad5dd;border-radius:9px;background:#fff;color:#71808c;font-size:11px;line-height:1;box-shadow:0 2px 7px #06193212;user-select:none}
 .layout-resizer:hover:before,.layout-resizer:focus-visible:before,.article-layout.is-resizing .layout-resizer:before{background:#c8962d;box-shadow:0 0 0 2px #f6e6bd}
 .layout-resizer:hover span,.layout-resizer:focus-visible span,.article-layout.is-resizing .layout-resizer span{border-color:#c8962d;color:#805c14;background:#fff9e9}
 body.is-layout-resizing{cursor:col-resize;user-select:none}
}
@media(min-width:821px) and (max-width:1100px){.article-layout{--sidebar-width:min(calc(70% - 23px),calc(97.778dvh + 2px));gap:14px}}
@media(max-width:820px){.layout-resizer{display:none}}
@media(max-width:820px){.page-up-link{margin-top:14px}.back-to-courses,.page-up-link{min-height:32px;padding:5px 10px;font-size:12px}}
@media(max-width:520px){.article-heading{align-items:flex-start;flex-direction:column}.back-to-courses{order:-1}.page-up-link{margin-top:12px}}

/* Keep the enlarged player inside the viewport even when browser zoom reduces the usable height. */
.player-card.is-expanded{top:3dvh;left:50%;right:auto;bottom:auto;z-index:2147483100;width:min(1100px,94vw);max-height:94dvh;transform:translateX(-50%);overflow:auto}
.player-card.is-expanded video{width:100%;max-height:min(70dvh,calc(100dvh - 150px));aspect-ratio:16/9}
body.video-expanded{overflow:hidden}body.video-expanded #ale-contact-widget-host{visibility:hidden!important;pointer-events:none!important}
.player-expand{font-size:11px;background:none;border:0;color:#697886;padding:4px}

@media(min-width:821px){
 .sidebar-sticky{max-height:calc(100dvh - 36px);display:flex;flex-direction:column}
 .player-card:not(.is-expanded){flex:none}
 .player-card:not(.is-expanded) video{max-height:55dvh}
 .player-card:not(.is-expanded) .player-heading{padding:8px 12px}
 .player-card:not(.is-expanded) .player-info:has(#player-context[hidden]){display:none}
 .player-card:not(.is-expanded) .player-controls{padding:5px 8px 7px;gap:4px}
 .player-card:not(.is-expanded) .player-controls button{padding:3px 6px}
 .player-card:not(.is-expanded) .player-controls:has(#replay:disabled){display:none}
 .desktop-toc{flex:1;min-height:0;max-height:none;padding-top:11px}
 .desktop-toc .toc-heading{margin-bottom:6px}
 .desktop-toc a{padding:4px 8px;line-height:1.45}
 .sidebar-platform,.sidebar-back{display:none}
}
@media(max-width:820px){.player-card.is-expanded video{max-height:min(64dvh,calc(100dvh - 135px))}}

/* Two familiar reading modes share the same official video player. */
.reading-mode-tabs{display:grid;grid-template-columns:1fr 1fr;gap:0;margin:0 0 20px;border:1px solid #cfd9e2;border-radius:7px;background:#f3f6f8;overflow:hidden;scroll-margin-top:var(--reading-offset,22px)}
.reading-mode-tabs button{position:relative;min-height:44px;border:0;border-right:1px solid #d8e0e6;background:transparent;color:#62717e;font-size:15px;font-weight:600;cursor:pointer}
.reading-mode-tabs button:last-child{border-right:0}
.reading-mode-tabs button:hover{background:#fffaf0;color:var(--navy)}
.reading-mode-tabs button.selected{background:#fff;color:var(--navy);font-weight:700;box-shadow:inset 0 -3px #d6a33b}
.reading-mode-tabs button:focus-visible{z-index:1;outline:2px solid #315d80;outline-offset:-2px}
.article-exclusive{animation:reading-mode-in .15s ease-out}
@keyframes reading-mode-in{from{opacity:.65}to{opacity:1}}
@media(max-width:820px){.reading-mode-tabs{margin-bottom:17px}.reading-mode-tabs button{min-height:42px;font-size:14px}}
@media(prefers-reduced-motion:reduce){.article-exclusive{animation:none}}

/* Small links sit beside the exact sentence that names an official resource. */
.inline-resources{display:inline-flex;flex-wrap:wrap;gap:5px;margin-left:8px;vertical-align:2px}
.inline-resource-link{display:inline-flex;align-items:center;gap:3px;padding:1px 6px;border:1px solid #cbd8e3;border-radius:4px;background:#f5f8fb;color:#315d80;font-size:11px;font-weight:600;line-height:1.7;white-space:nowrap;text-decoration:none!important}
.inline-resource-link .icon{width:10px;height:10px;vertical-align:0}
.inline-resource-link:hover,.inline-resource-link:focus-visible{border-color:#8eaac1;background:#eaf1f7;color:#163e60}
@media(max-width:520px){.inline-resources{gap:4px;margin-left:5px}.inline-resource-link{font-size:10px;padding:1px 5px}}

/* Mobile homepage: one viewport should be enough to understand and choose. */
@media(max-width:520px){
 .home-page .site-header{height:50px}
 .home-page .header-inner{padding:0 12px;gap:4px}
 .home-page .brand{flex:none}
 .home-page .brand img{width:94px;height:28px}
 .home-page .site-header nav{gap:2px;font-size:11px}
 .home-page .site-header nav a{padding:6px 7px;min-height:34px;display:inline-flex;align-items:center}
 .home-page .site-header nav a.official-platform-link{padding:6px 7px;font-size:11px}
 .home-page .home-main{padding:0 12px}
 .home-page .page-up-link{display:none}
 .home-page .home-hero{display:grid;grid-template-columns:minmax(0,1fr) auto;align-items:end;gap:6px 10px;padding:12px 0 9px}
 .home-page .home-hero h1{font-size:21px;line-height:1.3;letter-spacing:-.3px;margin:0 0 3px}
 .home-page .hero-description{font-size:12px;line-height:1.45;max-width:28em}
 .home-page .notice-link{font-size:10px;margin:0;padding:0 0 2px}
 .home-page .notice-link .icon{width:11px;height:11px}
 .home-page .reading-guide{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:0;padding:7px 5px;border-radius:7px;font-size:10px}
 .home-page .reading-guide .guide-heading{display:none}
 .home-page .reading-guide>span:not(.guide-heading){display:flex;align-items:center;justify-content:center;gap:4px;min-width:0;white-space:nowrap}
 .home-page .reading-guide>span+span{border-left:1px solid var(--line)}
 .home-page .reading-guide b{width:auto;margin:0;font-size:10px}
 .home-page .reading-guide small{display:none}
 .home-page .legend-dot{width:5px;height:5px;margin:0}
 .home-page .courses{margin-top:10px}
 .home-page .section-intro{margin-bottom:7px}
 .home-page .section-intro h2{font-size:16px;line-height:1.35}
 .home-page .course-grid{grid-template-columns:repeat(2,minmax(0,1fr));gap:7px}
 .home-page .course-card{min-height:116px;padding:9px 10px 0;border-radius:8px}
 .home-page .card-top{margin-bottom:3px}
 .home-page .course-icon{width:28px;height:28px;border-radius:6px}
 .home-page .course-icon .icon{width:17px;height:17px}
 .home-page .video-duration{font-size:9px;gap:2px}
 .home-page .video-duration .icon{width:9px;height:9px}
 .home-page .course-card h2{font-size:16px;line-height:1.3;margin:0 0 2px}
 .home-page .course-card h2 .icon{width:12px;height:12px}
 .home-page .course-card>p{display:-webkit-box;min-height:33px;overflow:hidden;-webkit-box-orient:vertical;-webkit-line-clamp:2;font-size:11.5px;line-height:1.45}
 .home-page .card-tags{display:none}
 .home-page .card-bottom{margin:auto -10px 0;padding:5px 10px;border-top:1px solid #edf0f2;font-size:10px;line-height:1.4}
 .home-page .card-bottom .icon{width:12px;height:12px}
 .home-page .platform-training-entry{display:grid;grid-template-columns:28px minmax(0,1fr) auto;gap:9px;margin-top:7px;padding:8px 10px;border-radius:7px}
 .home-page .platform-training-entry .course-icon{width:28px;height:28px}
 .home-page .platform-training-entry h2{font-size:14px;line-height:1.3;margin:0}
 .home-page .platform-training-entry p{display:none}
 .home-page .platform-entry-action{width:auto;margin:0;padding:0;font-size:10px}
 .home-page .platform-entry-action .icon{width:12px;height:12px}
 .home-page .home-help{display:none}
}