:root{--btl-bg:#f1f5f9;--btl-panel:#fff;--btl-text:#0f172a;--btl-muted:#64748b;--btl-border:#dbe3ee;--btl-primary:#2563eb;--btl-code:#0f172a}.dark{--btl-bg:#0f172a;--btl-panel:#111c31;--btl-text:#e2e8f0;--btl-muted:#94a3b8;--btl-border:#26344d;--btl-primary:#60a5fa;--btl-code:#060b16}.btl-body{margin:0;background:var(--btl-bg);color:var(--btl-text);font-family:Inter,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif}.btl-body a{color:inherit}.btl-header{position:sticky;top:0;z-index:50;background:color-mix(in srgb,var(--btl-panel) 92%,transparent);border-bottom:1px solid var(--btl-border);backdrop-filter:blur(16px)}.btl-header-inner{max-width:1480px;margin:auto;padding:14px 24px;display:flex;align-items:center;justify-content:space-between;gap:20px}.btl-brand{display:flex;align-items:center;gap:12px;text-decoration:none}.btl-brand strong{display:block;font-size:1.15rem}.btl-brand small{display:block;color:var(--btl-muted);font-size:.72rem;letter-spacing:.08em;text-transform:uppercase}.btl-shield{display:grid;place-items:center;width:38px;height:38px;border-radius:12px;background:linear-gradient(135deg,#1d4ed8,#06b6d4);color:white}.btl-nav{display:flex;align-items:center;gap:10px}.btl-nav a,.btl-nav button{padding:8px 11px;border-radius:9px;text-decoration:none;border:0;background:transparent;color:var(--btl-muted);font-weight:600}.btl-nav a:hover,.btl-nav button:hover{background:var(--btl-bg);color:var(--btl-text)}.btl-footer{border-top:1px solid var(--btl-border);max-width:1480px;margin:60px auto 0;padding:28px 24px;text-align:center;color:var(--btl-muted);font-size:.9rem}.btl-footer div{margin:5px}.btl-footer p{margin:14px 0 0}.btl-breadcrumb{display:flex;align-items:center;gap:9px;color:var(--btl-muted);font-size:.85rem;margin-bottom:20px}.btl-breadcrumb a{text-decoration:none;color:var(--btl-primary)}.btl-layout{display:grid;grid-template-columns:285px minmax(0,1fr);max-width:1480px;margin:auto}.btl-sidebar{position:sticky;top:68px;height:calc(100vh - 68px);overflow:auto;padding:28px 22px;border-right:1px solid var(--btl-border);background:var(--btl-panel)}.btl-back{display:inline-flex;margin-bottom:22px;text-decoration:none;color:var(--btl-primary);font-weight:700}.btl-sidebar-title{font-size:.72rem;text-transform:uppercase;letter-spacing:.12em;color:var(--btl-muted);font-weight:800;margin-bottom:10px}.btl-mini-list{margin:0;padding:0;list-style:none}.btl-mini-list li a,.btl-sidebar-link{display:block;padding:8px 10px;margin:3px 0;border-radius:8px;text-decoration:none;color:var(--btl-muted);font-size:.87rem;line-height:1.3}.btl-mini-list li.active a,.btl-sidebar-link.active,.btl-mini-list li a:hover{background:color-mix(in srgb,var(--btl-primary) 13%,transparent);color:var(--btl-primary)}.btl-main{min-width:0;padding:34px clamp(22px,5vw,74px)}.lesson-article{max-width:980px;margin:auto;background:var(--btl-panel);border:1px solid var(--btl-border);border-radius:22px;overflow:hidden;box-shadow:0 18px 45px rgba(15,23,42,.07)}.lesson-header{padding:38px clamp(24px,5vw,58px);background:linear-gradient(135deg,color-mix(in srgb,var(--btl-primary) 14%,var(--btl-panel)),var(--btl-panel));border-bottom:1px solid var(--btl-border)}.lesson-header h1{font-size:clamp(2rem,5vw,3.5rem);line-height:1.08;margin:9px 0 16px;letter-spacing:-.035em}.lesson-section,.domain-label{display:inline-flex;padding:5px 10px;border-radius:999px;background:color-mix(in srgb,var(--btl-primary) 14%,transparent);color:var(--btl-primary);font-size:.72rem;font-weight:800;text-transform:uppercase;letter-spacing:.09em}.lesson-source{color:var(--btl-muted);font-size:.88rem;margin:0}.lesson-content{padding:36px clamp(24px,5vw,58px);font-size:1.03rem;line-height:1.8}.lesson-content h2{font-size:1.55rem;line-height:1.25;margin:38px 0 15px;padding-top:18px;border-top:1px solid var(--btl-border)}.lesson-content h3{font-size:1.18rem;margin:27px 0 10px;color:var(--btl-primary)}.lesson-content p{margin:0 0 19px}.lesson-content a,.glossary-entry a{color:var(--btl-primary);overflow-wrap:anywhere}.course-emphasis{font-style:italic}.course-list{padding-left:1.4rem;margin:0 0 24px}.course-list li{margin:8px 0}.course-figure,.glossary-cover{margin:28px 0}.course-figure img,.glossary-cover img{display:block;max-width:100%;height:auto;margin:auto;border-radius:13px;border:1px solid var(--btl-border);background:white}.course-figure figcaption{text-align:center;color:var(--btl-muted);font-size:.78rem;margin-top:8px}.lesson-content pre{white-space:pre-wrap;overflow:auto;background:var(--btl-code);color:#dbeafe;padding:18px;border-radius:12px;font-size:.88rem;line-height:1.55}.lesson-nav{max-width:980px;margin:22px auto;display:grid;grid-template-columns:1fr 1fr;gap:16px}.lesson-nav-card{display:flex;flex-direction:column;padding:17px;border:1px solid var(--btl-border);border-radius:13px;background:var(--btl-panel);text-decoration:none}.lesson-nav-card small{color:var(--btl-muted);margin-bottom:5px}.lesson-nav-next{text-align:right}.domain-page,.btl-home{max-width:1250px;margin:auto;padding:36px 24px}.domain-hero,.btl-home-hero{border:1px solid var(--btl-border);border-radius:25px;padding:clamp(30px,6vw,70px);background:radial-gradient(circle at 90% 10%,color-mix(in srgb,var(--domain-accent,#2563eb) 28%,transparent),transparent 35%),var(--btl-panel);overflow:hidden}.domain-hero h1,.btl-home-hero h1{font-size:clamp(2.5rem,7vw,5.3rem);line-height:1;max-width:950px;margin:16px 0;letter-spacing:-.055em}.domain-hero p,.btl-home-hero p{font-size:1.1rem;color:var(--btl-muted);max-width:800px;line-height:1.7}.domain-stats{display:flex;flex-wrap:wrap;gap:13px;margin-top:25px}.domain-stats span{padding:9px 13px;border-radius:10px;border:1px solid var(--btl-border);background:color-mix(in srgb,var(--btl-panel) 80%,transparent);color:var(--btl-muted)}.domain-stats strong{color:var(--btl-text);margin-right:4px}.domain-action{display:inline-flex;margin-top:22px;padding:11px 16px;background:var(--domain-accent,#2563eb);color:white!important;border-radius:10px;text-decoration:none;font-weight:800}.domain-toolbar{display:flex;align-items:center;justify-content:space-between;gap:15px;margin:32px 0 15px}.domain-toolbar input{width:min(570px,100%);padding:13px 16px;border-radius:12px;border:1px solid var(--btl-border);background:var(--btl-panel);color:var(--btl-text);outline:none}.domain-toolbar input:focus{border-color:var(--btl-primary);box-shadow:0 0 0 3px color-mix(in srgb,var(--btl-primary) 15%,transparent)}.domain-toolbar span{color:var(--btl-muted);font-size:.88rem}.course-section{margin:28px 0 48px}.section-heading{display:flex;align-items:center;gap:15px;margin-bottom:15px}.section-heading>span{display:grid;place-items:center;width:45px;height:45px;border-radius:13px;background:var(--btl-panel);border:1px solid var(--btl-border);font-weight:800;color:var(--btl-primary)}.section-heading h2{margin:0;font-size:1.55rem}.section-heading p{margin:3px 0 0;color:var(--btl-muted);font-size:.85rem}.lesson-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(260px,1fr));gap:12px}.lesson-card{display:grid;grid-template-columns:43px 1fr;column-gap:12px;padding:17px;border:1px solid var(--btl-border);border-radius:13px;background:var(--btl-panel);text-decoration:none;transition:.18s}.lesson-card:hover{transform:translateY(-2px);border-color:var(--btl-primary);box-shadow:0 12px 28px rgba(15,23,42,.08)}.lesson-card>span{grid-row:1/3;display:grid;place-items:center;border-radius:9px;background:var(--btl-bg);color:var(--btl-muted);font-family:ui-monospace,monospace;font-size:.75rem}.lesson-card strong{line-height:1.25}.lesson-card small{color:var(--btl-muted);margin-top:4px}.btl-domain-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(300px,1fr));gap:18px;margin-top:32px}.btl-domain-card{position:relative;overflow:hidden;display:flex;flex-direction:column;min-height:250px;padding:28px;border-radius:20px;border:1px solid var(--btl-border);background:var(--btl-panel);text-decoration:none}.btl-domain-card:before{content:"";position:absolute;right:-45px;top:-45px;width:150px;height:150px;border-radius:50%;background:var(--card-accent);opacity:.18}.btl-domain-card h2{font-size:1.55rem;line-height:1.15;margin:25px 0 9px}.btl-domain-card p{color:var(--btl-muted);line-height:1.55;flex:1}.btl-domain-card footer{display:flex;justify-content:space-between;color:var(--btl-muted);font-size:.82rem;margin-top:18px}.btl-domain-card:hover{border-color:var(--card-accent);transform:translateY(-3px)}.glossary-grid{display:grid;gap:14px;padding:32px clamp(22px,4vw,50px)}.glossary-entry{padding:20px;border:1px solid var(--btl-border);border-radius:13px;background:var(--btl-bg)}.glossary-entry h2{font-size:1.03rem;margin:0 0 8px}.glossary-entry h2 span{display:inline-block;color:var(--btl-primary);min-width:110px}.glossary-entry p{margin:0;color:var(--btl-muted);line-height:1.65}.glossary-cover{padding:0 clamp(22px,4vw,50px)}.training-note{padding:15px 18px;border-left:4px solid #f59e0b;background:color-mix(in srgb,#f59e0b 12%,var(--btl-panel));border-radius:0 11px 11px 0;color:var(--btl-muted);margin:25px 0}.hidden-by-filter{display:none!important}@media(max-width:900px){.btl-layout{display:block}.btl-sidebar{position:relative;top:auto;height:auto;border-right:0;border-bottom:1px solid var(--btl-border);padding:17px 20px}.btl-mini-list{display:none}.btl-main{padding:24px 16px}.lesson-nav{grid-template-columns:1fr}.btl-nav a:nth-child(2),.btl-nav a:nth-child(3){display:none}}@media(max-width:600px){.btl-header-inner{padding:10px 14px}.btl-brand small{display:none}.btl-nav{gap:2px}.domain-page,.btl-home{padding:24px 14px}.domain-toolbar{align-items:stretch;flex-direction:column}.domain-hero,.btl-home-hero{padding:28px 22px}.lesson-header,.lesson-content{padding-left:20px;padding-right:20px}.btl-domain-grid{grid-template-columns:1fr}}