:root{--ink:#242a27;--muted:#737971;--paper:#fffdf8;--line:#e9e4da;--soft:#f7f3ea;--accent:#a66f2e;--serif:Georgia,"Songti SC","Noto Serif SC",serif}*{box-sizing:border-box}body.classroom-body{margin:0;background:var(--paper);color:var(--ink);font-family:system-ui,-apple-system,BlinkMacSystemFont,"PingFang SC","Microsoft YaHei",sans-serif}.classroom-shell{width:min(1040px,calc(100% - 36px));margin:0 auto;padding:64px 0 96px}.classroom-hero{max-width:760px;margin:0 auto 42px}.classroom-hero p,.category-header>p,.knowledge-article header>p{margin:0 0 12px;color:var(--accent);font-size:13px;letter-spacing:.12em}.classroom-hero h1,.category-header h1,.knowledge-article h1{font:42px/1.2 var(--serif);margin:0 0 14px}.classroom-hero span,.category-header span{color:var(--muted)}.system-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:18px}.system-card{border:1px solid var(--line);border-radius:18px;background:#fff;padding:24px}.system-card h2{margin:0;font:25px var(--serif)}.system-card>p{font-size:13px;color:var(--muted)}.system-card ul{list-style:none;padding:0;margin:18px 0 0}.system-card li{border-top:1px solid #f0ede6}.system-card a{display:flex;justify-content:space-between;padding:12px 0;color:inherit;text-decoration:none}.system-card a:hover{color:var(--accent)}.system-card small{color:var(--muted)}
.knowledge-layout{display:grid;grid-template-columns:280px minmax(0,880px);min-height:calc(100vh - 76px)}.knowledge-sidebar{position:sticky;top:0;height:calc(100vh - 76px);overflow:auto;padding:30px 22px;border-right:1px solid var(--line);background:#fcfaf5}.knowledge-home{display:block;text-decoration:none;color:var(--ink);font-weight:700;font-size:15px;padding:12px;border-radius:9px}.knowledge-home:hover{background:var(--soft)}.knowledge-system{margin:24px 12px 9px;font-weight:700;color:var(--accent);font-size:13px}.knowledge-nav a{display:flex;gap:10px;justify-content:space-between;color:#414742;text-decoration:none;padding:10px 12px;border-radius:9px;font-size:14px}.knowledge-nav a:hover{background:var(--soft)}.knowledge-nav a.is-active{background:#f0e8d9;color:#523819;font-weight:700}.knowledge-nav small{font-size:11px;color:#999}.knowledge-main{width:min(860px,calc(100% - 76px));padding:58px 0 96px;margin-left:clamp(40px,7vw,112px)}.breadcrumbs{display:flex;flex-wrap:wrap;gap:8px;color:var(--muted);font-size:13px;margin-bottom:38px}.breadcrumbs a{color:inherit;text-decoration:none}.breadcrumbs a:hover{color:var(--accent)}.breadcrumbs b{font-weight:600;color:#4d534d}.category-header{padding-bottom:26px;border-bottom:1px solid var(--line);margin-bottom:14px}.article-list{border-top:1px solid var(--line)}.article-list a{display:flex;align-items:center;justify-content:space-between;gap:20px;padding:21px 8px;border-bottom:1px solid var(--line);color:inherit;text-decoration:none}.article-list a:hover{background:#fbf8f2;color:var(--accent)}.article-list span{display:grid;gap:5px}.article-list em{font-style:normal;font-size:12px;color:var(--accent)}.article-list b{font-size:17px}.article-list i{font-style:normal;font-size:20px;color:#9a8d79}.pager{display:flex;gap:16px;margin-top:28px;color:var(--muted)}.pager a{color:var(--accent)}
.article-main{max-width:800px}.knowledge-article header{padding-bottom:30px;border-bottom:1px solid var(--line)}.knowledge-article h1{font-size:46px;letter-spacing:.01em}.knowledge-article time{font-size:13px;color:var(--muted)}.article-content{font:18px/2.05 var(--serif);letter-spacing:.01em;padding:30px 0}.article-content p{margin:0 0 1.5em}.knowledge-article footer{margin-top:36px;padding-top:20px;border-top:1px solid var(--line);color:var(--muted);font-size:13px}
@media(max-width:860px){.system-grid{grid-template-columns:1fr}.knowledge-layout{display:block}.knowledge-sidebar{position:static;height:auto;border-right:0;border-bottom:1px solid var(--line);padding:12px 18px}.knowledge-system{margin:12px 0 6px}.knowledge-nav{display:flex;overflow:auto;gap:6px;padding-bottom:3px}.knowledge-nav a{white-space:nowrap;padding:8px 10px}.knowledge-nav small{display:none}.knowledge-main{width:calc(100% - 36px);margin:0 auto;padding:34px 0 72px}.knowledge-article h1,.category-header h1,.classroom-hero h1{font-size:33px}.breadcrumbs{margin-bottom:26px}.article-content{font-size:17px}}

/* Guided classroom landing — calm documentation UI with premium editorial rhythm. */
.classroom-home-body{background:#fbfaf6}.classroom-landing{width:min(1180px,calc(100% - 40px));margin:0 auto;padding:44px 0 110px}.classroom-command{position:relative;isolation:isolate;display:grid;grid-template-columns:minmax(0,720px) 1fr;min-height:500px;overflow:hidden;border:1px solid rgba(37,43,39,.08);border-radius:28px;background:radial-gradient(circle at 76% 18%,rgba(208,174,107,.2),transparent 31%),linear-gradient(135deg,#fff 0%,#f8f4e9 58%,#f2ead9 100%);box-shadow:0 22px 70px rgba(81,65,35,.08)}.command-copy{padding:60px 68px;position:relative;z-index:2}.command-kicker{display:inline-flex;align-items:center;gap:9px;padding:7px 13px;border:1px solid rgba(137,93,35,.15);border-radius:999px;background:rgba(255,255,255,.72);color:#8d5c1f;font-size:12px;font-weight:600;letter-spacing:.08em}.command-kicker i{width:7px;height:7px;border-radius:50%;background:#c98d38;box-shadow:0 0 0 5px rgba(201,141,56,.12)}.command-copy h1{margin:24px 0 18px;font:600 clamp(42px,5vw,66px)/1.12 var(--serif);letter-spacing:-.045em;color:#1d2521}.command-copy>p{max-width:610px;margin:0;color:#657069;font-size:17px;line-height:1.8}.classroom-search{display:grid;grid-template-columns:32px minmax(0,1fr) 132px;align-items:center;gap:8px;max-width:680px;margin-top:32px;padding:7px 8px 7px 17px;border:1px solid rgba(23,31,26,.1);border-radius:16px;background:#fff;box-shadow:0 8px 26px rgba(56,47,29,.06)}.classroom-search:focus-within{border-color:rgba(166,111,46,.5);box-shadow:0 0 0 4px rgba(166,111,46,.08),0 8px 26px rgba(56,47,29,.06)}.classroom-search>span{font-size:24px;color:#9b8c73}.classroom-search input{width:100%;min-width:0;border:0;outline:0;background:transparent;font-size:15px;color:var(--ink)}.classroom-search input::placeholder{color:#9b9f9b}.classroom-search button{white-space:nowrap;display:grid;place-items:center;min-width:132px;height:44px;border:0;border-radius:11px;background:#232a26;color:#fff;padding:0 18px;font-weight:600;cursor:pointer}.classroom-search button:hover{background:#9b692d}.command-stats{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:10px;margin-top:22px}.command-stats span{display:grid;grid-template-columns:30px minmax(0,1fr);column-gap:9px;align-items:center;min-height:58px;padding:9px 11px;border:1px solid rgba(79,69,48,.08);border-radius:13px;background:rgba(255,255,255,.55)}.command-stats i{grid-row:1/3;display:grid;place-items:center;width:30px;height:30px;border-radius:10px;background:#f1e6d1;color:#936329;font:600 13px var(--serif);font-style:normal}.command-stats b{font-size:12px;color:#303934}.command-stats small{overflow:hidden;color:#888e89;font-size:10px;white-space:nowrap;text-overflow:ellipsis}.command-orbit{position:relative;min-height:100%}.command-orbit:before,.command-orbit:after,.orbit-one,.orbit-two{content:"";position:absolute;border:1px solid rgba(147,103,47,.2);border-radius:50%}.command-orbit:before{width:430px;height:430px;right:-130px;top:10px}.command-orbit:after{width:320px;height:320px;right:-75px;top:65px}.orbit-one{width:190px;height:190px;right:-10px;top:130px;background:rgba(255,255,255,.22)}.orbit-two{width:10px;height:10px;right:283px;top:88px;background:#c98d38;box-shadow:0 0 0 8px rgba(201,141,56,.1)}.command-brand-mark{position:absolute;right:91px;top:148px;display:flex;flex-direction:column;align-items:center;gap:6px;padding:18px 14px;border:1px solid rgba(147,103,47,.18);border-radius:999px;background:rgba(255,253,248,.46);font:500 29px/1.1 var(--serif);letter-spacing:0;color:#7d5a28}.command-brand-mark span{color:#a66f2e}
.direction-section,.path-section,.featured-section,.catalog-section,.search-results{padding-top:82px}.section-heading{display:flex;align-items:end;justify-content:space-between;gap:32px;margin-bottom:26px}.section-heading>div>span{display:block;margin-bottom:9px;color:#a47235;font:600 11px/1.4 ui-monospace,SFMono-Regular,Menlo,monospace;letter-spacing:.15em}.section-heading h2{margin:0;font:500 34px/1.2 var(--serif);letter-spacing:-.025em}.section-heading>p{max-width:420px;margin:0;color:#7d837e;font-size:14px;line-height:1.7}.direction-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:18px}.direction-card{position:relative;overflow:hidden;min-height:340px;padding:28px;border:1px solid rgba(37,43,39,.07);border-radius:22px;background:#fff;box-shadow:0 4px 20px rgba(53,47,35,.035);transition:transform .2s,border-color .2s,box-shadow .2s}.direction-card:after{content:"";position:absolute;width:180px;height:180px;right:-75px;top:-75px;border-radius:50%;background:var(--card-glow)}.direction-card:hover{transform:translateY(-4px);border-color:rgba(166,111,46,.22);box-shadow:0 18px 44px rgba(53,47,35,.08)}.tone-amber{--card-glow:rgba(229,185,107,.2)}.tone-violet{--card-glow:rgba(163,137,196,.16)}.tone-indigo{--card-glow:rgba(106,135,180,.15)}.direction-card-top{display:flex;justify-content:space-between;align-items:center}.direction-mark{display:grid;place-items:center;width:42px;height:42px;border:1px solid rgba(147,103,47,.18);border-radius:13px;background:#fbf7ed;color:#916326;font:600 18px var(--serif)}.direction-card-top small{color:#aaa394;font:500 10px ui-monospace,SFMono-Regular,monospace;letter-spacing:.13em}.direction-card h3{margin:27px 0 12px;font:500 27px var(--serif)}.direction-card>p{min-height:70px;margin:0;color:#707872;font-size:14px;line-height:1.75}.direction-metrics{display:flex;gap:18px;margin:22px 0;color:#888e89;font-size:12px}.direction-card>a{display:flex;align-items:center;justify-content:space-between;color:#28302c;text-decoration:none;font-size:14px;font-weight:600}.direction-card>a i{font-style:normal;font-size:19px}.direction-card>a:hover{color:#a66f2e}
.path-board{display:grid;grid-template-columns:1fr 34px 1fr 34px 1fr;align-items:center;padding:34px;border:1px solid rgba(37,43,39,.07);border-radius:24px;background:#202723;color:#fff;box-shadow:0 18px 50px rgba(25,31,27,.12)}.path-board>article{display:grid;grid-template-columns:46px 1fr;gap:16px}.path-board>article>span{display:grid;place-items:center;width:42px;height:42px;border:1px solid rgba(255,255,255,.14);border-radius:12px;color:#d8b57d;font:500 12px ui-monospace,SFMono-Regular,monospace}.path-board small{color:#c4a878;font-size:11px;letter-spacing:.1em}.path-board h3{margin:5px 0 7px;font-size:16px}.path-board p{margin:0;color:#aeb6b0;font-size:12px;line-height:1.65}.path-board>i{text-align:center;color:#7c8780;font-style:normal}.featured-grid,.search-result-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:14px}.featured-grid>a,.search-result-grid>a{min-height:190px;padding:24px;border:1px solid rgba(37,43,39,.07);border-radius:18px;background:#fff;color:inherit;text-decoration:none;transition:border-color .2s,transform .2s}.featured-grid>a:hover,.search-result-grid>a:hover{transform:translateY(-3px);border-color:rgba(166,111,46,.25)}.featured-grid span,.search-result-grid small{color:#a06e31;font-size:11px;letter-spacing:.06em}.featured-grid h3,.search-result-grid b{display:block;margin:15px 0 10px;font:500 19px/1.45 var(--serif)}.featured-grid p{color:#858b86;font-size:13px;line-height:1.6}.featured-grid i,.search-result-grid span{color:#4e5751;font-style:normal;font-size:12px}.empty-search{grid-column:1/-1;padding:40px;border:1px dashed #ddd5c8;border-radius:18px;text-align:center;color:#6f756f}.catalog-accordions{display:grid;gap:12px}.catalog-accordions details{border:1px solid rgba(37,43,39,.07);border-radius:18px;background:#fff}.catalog-accordions summary{display:grid;grid-template-columns:44px 1fr auto;align-items:center;gap:15px;padding:18px 22px;cursor:pointer;list-style:none}.catalog-accordions summary::-webkit-details-marker{display:none}.catalog-accordions summary>div{display:grid;gap:3px}.catalog-accordions summary b{font:500 18px var(--serif)}.catalog-accordions summary small{color:#8a8f8b;font-size:12px}.catalog-accordions summary>i{font-style:normal;color:#9b8c73;transition:transform .2s}.catalog-accordions details[open] summary>i{transform:rotate(180deg)}.catalog-links{display:grid;grid-template-columns:repeat(3,1fr);gap:1px;padding:0 22px 22px}.catalog-links a{display:flex;justify-content:space-between;gap:10px;padding:11px 12px;border-radius:9px;color:#454c47;text-decoration:none;font-size:13px}.catalog-links a:hover{background:#f7f2e8;color:#9b692d}.catalog-links small{color:#9a9e9a;white-space:nowrap}
@media(max-width:900px){.classroom-command{grid-template-columns:1fr}.command-copy{padding:48px 34px}.command-orbit{display:none}.direction-grid,.featured-grid,.search-result-grid{grid-template-columns:1fr}.path-board{grid-template-columns:1fr;gap:20px}.path-board>i{transform:rotate(90deg)}.catalog-links{grid-template-columns:repeat(2,1fr)}.section-heading{align-items:start;flex-direction:column;gap:10px}}
@media(max-width:600px){.classroom-landing{width:min(100% - 24px,1180px);padding-top:20px}.classroom-command{border-radius:20px}.command-copy{padding:34px 22px}.command-copy h1{font-size:38px}.classroom-search{grid-template-columns:26px minmax(0,1fr) 104px;gap:5px;padding:7px 7px 7px 11px}.classroom-search input{font-size:14px}.classroom-search button{grid-column:auto;width:auto;min-width:104px;height:42px;padding:0 11px;font-size:12px}.command-stats{grid-template-columns:1fr;gap:7px}.command-stats span{min-height:52px}.direction-section,.path-section,.featured-section,.catalog-section,.search-results{padding-top:58px}.section-heading h2{font-size:28px}.catalog-links{grid-template-columns:1fr}.catalog-accordions summary{padding:15px}.path-board{padding:24px 20px}}
.classroom-search .sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}
.guided-article header{margin-bottom:24px}.reading-lens{display:grid;grid-template-columns:auto 1fr;gap:14px;align-items:start;margin:0 0 30px;padding:18px 20px;border:1px solid rgba(166,111,46,.18);border-radius:16px;background:linear-gradient(135deg,#fbf5e8,#fffdf8)}.reading-lens span{color:#98682e;font-size:12px;font-weight:700;letter-spacing:.08em}.reading-lens p{margin:0;color:#59635c;font-size:14px;line-height:1.8}.article-sections{display:grid;gap:28px}.article-section{padding-bottom:24px;border-bottom:1px solid var(--line)}.article-section:last-child{border-bottom:0}.article-section h2{margin:0 0 14px;font:500 24px/1.35 var(--serif);color:#303832}.article-section p{margin:0 0 1.1em;font:18px/2.05 var(--serif);letter-spacing:.01em}.article-section p:last-child{margin-bottom:0}
.category-overview{margin:28px 0 42px;padding:28px;border:1px solid rgba(37,43,39,.08);border-radius:20px;background:#fff}.category-overview-heading>span{display:block;margin-bottom:8px;color:#a47235;font:600 11px ui-monospace,SFMono-Regular,monospace;letter-spacing:.15em}.category-overview-heading h2{margin:0 0 24px;font:500 29px var(--serif)}.category-overview .reading-lens{margin-bottom:26px}.category-list-title{margin:0 0 14px;font:500 25px var(--serif)}.category-empty{padding:26px 0;color:var(--muted)}
.knowledge-layout{grid-template-columns:260px minmax(0,1fr);background:#fbfaf6}.knowledge-sidebar{padding:28px 16px;background:#f8f6f0;border-right:1px solid #e5e0d5}.knowledge-home{padding:11px 12px;font-size:14px;border-radius:11px}.knowledge-system{margin:24px 10px 9px;font-size:12px;letter-spacing:.08em}.knowledge-nav a{display:flex;gap:8px;justify-content:space-between;padding:9px 10px;font-size:13px;line-height:1.4;border-radius:10px}.knowledge-nav a.is-active{box-shadow:inset 3px 0 #b0803c}.knowledge-nav small{min-width:25px;text-align:right;color:#a09b91}.knowledge-main{width:min(800px,calc(100% - 48px));padding:54px 0 104px;margin:0 auto}.breadcrumbs{margin-bottom:28px;font-size:12px}.knowledge-article h1{font-size:42px;line-height:1.25}.article-section p{margin:0 0 1.1em;font:17px/2.15 var(--serif);color:#4d554f}.category-overview{padding:26px 28px}.article-list a{padding:18px 8px}
@media(max-width:860px){.knowledge-layout{display:block}.knowledge-sidebar{padding:12px 16px}.knowledge-main{width:calc(100% - 36px);margin:0 auto;padding:34px 0 72px}.knowledge-article h1,.category-header h1{font-size:33px}}
@media(max-width:600px){.knowledge-sidebar{padding:10px 12px}.knowledge-main{width:calc(100% - 28px)}.reading-lens{grid-template-columns:1fr;gap:7px;padding:15px}.category-overview{padding:20px 16px}.article-section h2{font-size:22px}.article-section p{font-size:16px;line-height:2}.knowledge-nav a{padding:8px 9px}}
.knowledge-main{margin-left:80px;margin-right:0}
@media(max-width:860px){.knowledge-main{margin:0 auto}}
.chapter-nav{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:12px;margin-top:54px;padding-top:18px;border-top:1px solid var(--line)}.chapter-nav a,.chapter-nav-placeholder{display:grid;gap:7px;min-height:76px;padding:14px 15px;border:1px solid #e7e1d7;border-radius:12px;color:inherit;text-decoration:none;background:#fffdfa}.chapter-nav a:hover{border-color:#c69b5c;background:#fbf7ee}.chapter-nav small{font-size:11px;color:var(--accent);letter-spacing:.08em}.chapter-nav strong{font-size:14px;line-height:1.55;font-weight:600}.chapter-nav-home{text-align:center;background:#f8f1e5!important;border-color:#ead9bd!important}.chapter-nav-next{text-align:right}.chapter-nav-placeholder{color:#aaa59d;background:#faf9f5}.category-chapter-nav{margin-top:46px}
@media(max-width:600px){.chapter-nav{grid-template-columns:1fr;gap:8px;margin-top:38px}.chapter-nav-next,.chapter-nav-home{text-align:left}.chapter-nav-placeholder{min-height:58px}}
.category-chapter-nav-pair{grid-template-columns:repeat(2,minmax(0,1fr))}
@media(max-width:600px){.category-chapter-nav-pair{grid-template-columns:1fr}}
.knowledge-main{margin-left:auto;margin-right:auto}
@media(max-width:860px){.knowledge-main{margin-left:auto;margin-right:auto}}

/* Reading polish: keep long lessons calm and scannable on wide screens. */
.article-main{width:min(920px,calc(100% - 64px))}
.article-sections{gap:0}
.article-section{padding:30px 0}
.article-section h2{display:flex;align-items:center;gap:12px}
.article-section h2::before{width:4px;height:1.1em;border-radius:99px;background:#c59a5c;content:""}
.article-section p{max-width:72ch;text-wrap:pretty}
.chapter-nav{max-width:920px}
@media(max-width:860px){.article-main{width:calc(100% - 36px)}}

/* Hierarchical classroom navigation: system → chapter → article. */
.knowledge-sidebar .knowledge-system{display:block;margin:24px 10px 9px;color:var(--accent);font-size:12px;font-weight:700;letter-spacing:.08em;text-decoration:none}.knowledge-sidebar .knowledge-system:hover{color:#744719;text-decoration:underline;text-underline-offset:4px}.knowledge-nav{display:grid;gap:5px}.knowledge-nav-group{overflow:hidden;border:1px solid transparent;border-radius:10px}.knowledge-nav-group[open]{border-color:#e8dfd0;background:#fffdfa}.knowledge-nav-group.is-active{border-color:#dfc89f;background:#fbf5e9;box-shadow:inset 3px 0 #b0803c}.knowledge-nav-group summary{display:grid;grid-template-columns:minmax(0,1fr) auto auto;align-items:center;gap:8px;padding:10px 10px;cursor:pointer;color:#414742;font-size:13px;list-style:none}.knowledge-nav-group summary::-webkit-details-marker{display:none}.knowledge-nav-group summary span{overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.knowledge-nav-group summary small{min-width:25px;color:#a09b91;font-size:11px;text-align:right}.knowledge-nav-group summary i{color:#9b8c73;font-size:12px;font-style:normal;transition:transform .18s ease}.knowledge-nav-group[open] summary i{transform:rotate(180deg)}.knowledge-nav-group summary:hover{background:var(--soft)}.knowledge-nav-group.is-active summary{color:#523819;font-weight:700}.knowledge-nav-children{display:grid;gap:2px;padding:0 7px 8px}.knowledge-nav-children a{display:block!important;padding:7px 9px 7px 22px!important;border-radius:7px!important;color:#687069!important;font-size:12px!important;line-height:1.45;text-decoration:none}.knowledge-nav-children a:hover{color:#8f5e24!important;background:#f5eddd!important}.knowledge-nav-children .knowledge-nav-overview{padding-left:9px!important;color:#94703a!important;font-weight:600}.knowledge-nav-children .knowledge-nav-child{position:relative}.knowledge-nav-children .knowledge-nav-child::before{position:absolute;top:0;bottom:0;left:10px;width:1px;content:"";background:#ddd4c4}.knowledge-nav-children .knowledge-nav-child.is-active{color:#583a18!important;background:#f0e5cf!important;font-weight:700}.knowledge-nav-children .knowledge-nav-child.is-active::before{background:#b0803c}
@media(max-width:860px){.knowledge-nav{display:grid;max-height:52vh;overflow:auto;padding:2px}.knowledge-nav-group{min-width:0}.knowledge-nav-children a{white-space:normal}.knowledge-sidebar .knowledge-system{margin:12px 0 8px}}