@import "https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&family=Outfit:wght@400;500;600;700;800&display=swap";:root{--lesson-accent:var(--accent-primary)}[data-theme=dark]{--lesson-accent:#34d399}.main{flex:1;max-width:100%;padding:0}.section{display:none}.section.active{display:block}.hero{margin-bottom:48px}.hero .eyebrow{font-family:var(--font-mono);color:var(--lesson-accent);letter-spacing:.12em;text-transform:uppercase;margin-bottom:12px;font-size:11px}.hero h2{font-family:var(--font-display);color:var(--text-primary);margin-bottom:14px;font-size:36px;font-weight:700;line-height:1.2}.hero h2 span{color:var(--lesson-accent)}.hero .lead{color:var(--text-secondary);max-width:580px;font-size:16px;line-height:1.8}.objectives-grid{grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:12px;margin:32px 0;display:grid}.obj-card{background:var(--bg-secondary);border:1px solid var(--border-color);border-radius:var(--radius-lg);padding:18px 20px;transition:border-color .2s}.obj-card:hover{border-color:var(--border-color)}.obj-num{font-family:var(--font-mono);color:var(--lesson-accent);margin-bottom:8px;font-size:11px}.obj-card h4{color:var(--text-primary);margin-bottom:6px;font-size:14px;font-weight:600;line-height:1.4}.obj-card p{color:var(--text-secondary);font-size:13px;line-height:1.6}.section-heading{font-family:var(--font-display);color:var(--text-primary);margin-bottom:8px;font-size:24px;font-weight:700;line-height:1.3}.section-subheading{font-family:var(--font-display);color:var(--text-primary);margin:32px 0 10px;font-size:18px;font-weight:500}.prose{color:var(--text-secondary);max-width:660px;margin-bottom:20px;font-size:15px;line-height:1.8}.prose strong{color:var(--text-primary);font-weight:500}.key-box{background:var(--bg-secondary);border:1px solid var(--border-color);border-left:3px solid var(--lesson-accent);border-radius:var(--radius);margin:24px 0;padding:18px 20px}.key-box.green{border-left-color:var(--lesson-accent)}.key-box.amber{border-left-color:#f5a623}.key-box.pink{border-left-color:var(--error)}.key-box.purple{border-left-color:var(--lesson-accent)}.key-box .kb-label{font-family:var(--font-mono);color:var(--text-secondary);letter-spacing:.1em;text-transform:uppercase;margin-bottom:6px;font-size:10px}.key-box p{color:var(--text-primary);font-size:15px;line-height:1.7}.tri-grid{grid-template-columns:repeat(auto-fit,minmax(180px,1fr));gap:12px;margin:20px 0;display:grid}.tri-card{background:var(--bg-secondary);border:1px solid var(--border-color);border-radius:var(--radius-lg);padding:20px}.tri-card .tc-icon{margin-bottom:10px;font-size:22px}.tri-card h4{color:var(--text-primary);margin-bottom:6px;font-size:14px;font-weight:600}.tri-card p{color:var(--text-secondary);font-size:13px;line-height:1.6}.venn-wrap{background:var(--bg-secondary);border:1px solid var(--border-color);border-radius:var(--radius-lg);margin:24px 0;padding:28px 24px}.venn-label{color:var(--text-secondary);font-size:11px;font-family:var(--font-mono);text-transform:uppercase;letter-spacing:.1em;margin-bottom:16px}.venn-diagram{justify-content:center;align-items:center;gap:0;height:160px;margin-bottom:24px;display:flex;position:relative}.venn-circle{cursor:pointer;border:2px solid #0000;border-radius:50%;flex-direction:column;justify-content:center;align-items:center;transition:opacity .2s,transform .2s;display:flex;position:absolute}.venn-circle:hover{opacity:.9;transform:scale(1.03)}.venn-circle.selected{border:2px solid var(--text-primary)}.vc-ia{background:#4f8ef71f;width:160px;height:160px;top:0;left:0}.vc-ml{background:#2ecc9a26;width:120px;height:120px;top:20px;left:70px}.vc-dl{background:#a78bfa33;width:82px;height:82px;top:39px;left:115px}.venn-circle span{color:var(--text-primary);pointer-events:none;text-align:center;padding:4px;font-size:12px;font-weight:600;line-height:1.2}.venn-info{background:var(--bg-secondary);border-radius:var(--radius);min-height:80px;padding:16px 18px;transition:all .2s}.venn-info h4{color:var(--text-primary);margin-bottom:6px;font-size:14px;font-weight:500}.venn-info p{color:var(--text-secondary);font-size:13px;line-height:1.6}.vocab-table{border-collapse:collapse;width:100%;margin:20px 0;font-size:14px}.vocab-table th{text-align:left;background:var(--bg-secondary);color:var(--text-secondary);text-transform:uppercase;letter-spacing:.06em;border-bottom:1px solid var(--border-color);padding:10px 16px;font-size:12px;font-weight:500}.vocab-table td{border-bottom:1px solid var(--border-color);color:var(--text-primary);vertical-align:top;padding:11px 16px}.vocab-table td:first-child{font-family:var(--font-mono);color:var(--lesson-accent);font-size:13px}.vocab-table td:nth-child(2){color:var(--lesson-accent)}.vocab-table tr:hover td{background:#ffffff05}.tool-selector{margin:24px 0}.ts-question{color:var(--text-secondary);margin-bottom:14px;font-size:13px}.ts-buttons{flex-wrap:wrap;gap:8px;margin-bottom:16px;display:flex}.ts-btn{border:1px solid var(--border-color);border-radius:var(--radius);background:var(--bg-secondary);color:var(--text-secondary);cursor:pointer;font-size:13px;font-family:var(--font-body);padding:8px 16px;transition:all .15s}.ts-btn:hover{border-color:var(--lesson-accent);color:var(--text-primary)}.ts-btn.selected{border-color:var(--lesson-accent);color:var(--lesson-accent);background:#4f8ef71a}.ts-result{background:var(--bg-secondary);border:1px solid var(--border-color);border-left:3px solid var(--lesson-accent);border-radius:var(--radius);padding:16px 18px;display:none}.ts-result.visible{display:block}.ts-result .ts-tool{color:var(--lesson-accent);margin-bottom:4px;font-size:16px;font-weight:600}.ts-result .ts-why{color:var(--text-secondary);font-size:13px}.quiz-wrap{margin:24px 0}.quiz-q{background:var(--bg-secondary);border:1px solid var(--border-color);border-radius:var(--radius-lg);margin-bottom:12px;padding:22px 24px}.quiz-q .q-text{color:var(--text-primary);margin-bottom:14px;font-size:15px;font-weight:500}.quiz-options{grid-template-columns:1fr 1fr;gap:8px;display:grid}.quiz-opt{border:1px solid var(--border-color);border-radius:var(--radius);color:var(--text-secondary);cursor:pointer;background:var(--bg-secondary);padding:10px 14px;font-size:13px;transition:all 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.c-gray{color:#8b949e}.code-header{justify-content:space-between;align-items:center;margin-bottom:12px;display:flex}.code-lang{font-family:var(--font-mono);color:var(--text-secondary);letter-spacing:.1em;text-transform:uppercase;font-size:10px}.copy-btn{color:var(--text-secondary);border:1px solid var(--border-color);cursor:pointer;font-size:11px;font-family:var(--font-body);background:0 0;border-radius:6px;padding:4px 10px;transition:all .15s}.copy-btn:hover{color:var(--text-primary);border-color:var(--lesson-accent)}.warn-box{border-radius:var(--radius);color:#f5c842;background:#f5a62314;border:1px solid #f5a62340;margin:20px 0;padding:14px 18px;font-size:14px;line-height:1.6}.warn-box strong{color:#f5a623}.case-grid{grid-template-columns:1fr 1fr;gap:12px;margin:20px 0;display:grid}.case-card{background:var(--bg-secondary);border:1px solid var(--border-color);border-top:2px solid var(--lesson-accent);border-radius:var(--radius-lg);padding:20px}.case-card .cc-tag{font-size:10px;font-family:var(--font-mono);color:var(--lesson-accent);letter-spacing:.1em;text-transform:uppercase;margin-bottom:8px}.case-card h4{color:var(--text-primary);margin-bottom:6px;font-size:14px;font-weight:600}.case-card p{color:var(--text-secondary);font-size:13px;line-height:1.6}.table-wrap{width:100%;margin:20px 0;overflow-x:auto}.comp-table,.vocab-table{border-collapse:collapse;width:100%;min-width:600px;font-size:14px}.comp-table th{text-align:left;background:var(--bg-secondary);color:var(--text-secondary);text-transform:uppercase;letter-spacing:.06em;border-bottom:1px solid var(--border-color);padding:12px 16px;font-size:12px;font-weight:500}.comp-table td{border-bottom:1px solid var(--border-color);color:var(--text-primary);vertical-align:top;padding:12px 16px}.comp-table td:first-child{color:#f5a623;font-weight:500}.comp-table tr:hover td{background:#ffffff05}.tag-pill{color:var(--lesson-accent);font-size:11px;font-family:var(--font-mono);background:#4f8ef71f;border-radius:99px;margin-right:4px;padding:2px 10px;display:inline-block}.nav-buttons{border-top:1px solid var(--border-color);justify-content:space-between;align-items:center;margin-top:56px;padding-top:24px;display:flex}.btn-nav{border-radius:var(--radius);cursor:pointer;font-size:14px;font-weight:500;font-family:var(--font-body);border:1px solid var(--border-color);background:var(--bg-secondary);color:var(--text-primary);padding:10px 22px;transition:all 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p{color:var(--text-secondary);font-size:12px;line-height:1.5}.limit-grid{grid-template-columns:1fr 1fr;gap:10px;margin:20px 0;display:grid}.limit-card{background:var(--bg-secondary);border:1px solid var(--border-color);border-radius:var(--radius);border-left:3px solid #e05c7b80;padding:14px 16px}.limit-card h4{color:var(--error);margin-bottom:5px;font-size:13px;font-weight:600}.limit-card p{color:var(--text-secondary);font-size:13px;line-height:1.5}.py-compare{grid-template-columns:1fr 1fr;gap:12px;margin:20px 0;display:grid}.py-col{border-radius:var(--radius-lg);padding:20px}.py-col.bad{background:#e05c7b12;border:1px solid #e05c7b33}.py-col.good{background:#2ecc9a12;border:1px solid #2ecc9a33}.py-col h4{margin-bottom:12px;font-size:14px;font-weight:600}.py-col.bad h4{color:var(--error)}.py-col.good h4{color:var(--lesson-accent)}.py-col ul{list-style:none}.py-col ul li{color:var(--text-secondary);padding-left:14px;font-size:13px;line-height:1.7;position:relative}.py-col ul li:before{content:"—";color:var(--text-secondary);position:absolute;left:0}.steps{margin:24px 0}.step{gap:16px;margin-bottom:20px;display:flex}.step-num-col{flex-direction:column;align-items:center;display:flex}.step-num{width:32px;height:32px;font-family:var(--font-mono);color:var(--lesson-accent);background:#4f8ef726;border:1px solid #4f8ef74d;border-radius:50%;flex-shrink:0;justify-content:center;align-items:center;font-size:12px;display:flex}.step-line{background:var(--border-color);flex:1;width:1px;margin:4px 0}.step- .step-body h4{color:var(--text-primary);margin-bottom:5px;font-size:14px;font-weight:600}.step-body p{color:var(--text-secondary);font-size:13px;line-height:1.6}.interactive-lesson ::-webkit-scrollbar{width:6px}.interactive-lesson ::-webkit-scrollbar-track{background:0 0}.interactive-lesson ::-webkit-scrollbar-thumb{background:var(--border-color);border-radius:99px}@media (width<=800px){.main{flex:1;max-width:100%;padding:0}.quiz-options,.case-grid,.limit-grid,.py-compare{grid-template-columns:1fr}.hero h2{font-size:26px}}.lesson-tabs-container{border-bottom:1px solid var(--border-color);margin-bottom:2rem;overflow-x:auto}.lesson-tabs{gap:1rem;min-width:max-content;padding-bottom:.5rem;display:flex}.lesson-tab{color:var(--text-secondary);cursor:pointer;background:0 0;border:none;border-bottom:2px solid #0000;padding:.75rem 1rem;font-size:.95rem;font-weight:500;transition:all .2s}.lesson-tab:hover{color:var(--text-primary)}.lesson-tab.active{color:var(--lesson-accent);border-bottom-color:var(--lesson-accent)}.lesson-tab:disabled{opacity:.4;cursor:not-allowed}.lesson-tab:disabled:hover{color:var(--text-secondary)}.interactive-lesson .section{display:block}.hero{margin-top:1rem}:root{--bg-primary:#f8fafc;--bg-secondary:#fff;--bg-card:#fff;--text-primary:#0b0e14;--text-secondary:#475569;--brand-green:#1a4c3e;--brand-green-rgb:26, 76, 62;--accent-primary:var(--brand-green);--accent-primary-rgb:var(--brand-green-rgb);--accent-secondary:#12372d;--accent-hover:#11362b;--border-color:#0000001a;--error:#ef4444;--sidebar-width:260px;--topbar-height:60px}[data-theme=dark]{--bg-primary:#0b0e14;--bg-secondary:#131821;--bg-card:#131821;--text-primary:#f8fafc;--text-secondary:#94a3b8;--accent-primary:#28b08a;--accent-primary-rgb:40, 176, 138;--accent-secondary:#1f896b;--accent-hover:#34d3a3;--border-color:#ffffff1a;--error:#ef4444}*{box-sizing:border-box;-webkit-tap-highlight-color:transparent;margin:0;padding:0}html,body{width:100%;height:100%;margin:0;padding:0;overflow:hidden}body{background-color:var(--bg-primary);color:var(--text-primary);-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale;font-family:Inter,sans-serif}h1,h2,h3,h4,h5,h6{font-family:Outfit,sans-serif}.glass-panel{background:var(--bg-card);border:1px solid var(--border-color);border-radius:8px}.gradient-text{color:var(--accent-primary);font-weight:700}.animate-fade-in{animation:.5s cubic-bezier(.4,0,.2,1) forwards fadeIn}.animate-slide-up{animation:.6s cubic-bezier(.16,1,.3,1) forwards slideUp}@keyframes fadeIn{0%{opacity:0}to{opacity:1}}@keyframes slideUp{0%{opacity:0;transform:translateY(20px)}to{opacity:1;transform:translateY(0)}}.auth-layout{background-color:var(--bg-primary);flex-direction:column;height:100dvh;display:flex;overflow-y:auto}.auth-container{width:100%;max-width:440px;margin:auto;padding:1.5rem}@media (width>=768px){.auth-container{padding:2.5rem}}.auth-header{text-align:center;margin-bottom:2rem}.auth-header h1{margin-bottom:.5rem;font-size:1.75rem}@media (width>=768px){.auth-header h1{font-size:2rem}}.auth-header p{color:var(--text-secondary);font-size:.95rem}.form-group{margin-bottom:1.25rem}.form-row{grid-template-columns:1fr;gap:1rem;display:grid}@media (width>=640px){.form-row{grid-template-columns:1fr 1fr}}.form-label{color:var(--text-secondary);margin-bottom:.5rem;font-size:.875rem;font-weight:500;display:block}.form-input{border:1px solid var(--border-color);width:100%;color:var(--text-primary);background:#00000008;border-radius:8px;padding:.75rem 1rem;font-size:1rem;transition:all .2s}.form-input:focus{border-color:var(--accent-primary);background:#0000000d;outline:none}.form-input::placeholder{color:#94a3b880}.btn{cursor:pointer;border:1px solid #0000;border-radius:8px;justify-content:center;align-items:center;width:100%;padding:.75rem 1.5rem;font-family:Outfit,sans-serif;font-size:1rem;font-weight:600;transition:all .2s;display:inline-flex}.btn-primary{background:var(--accent-primary);color:#fff}.btn-primary:hover{background:var(--accent-hover)}.btn-secondary{color:var(--text-primary);border:1px solid var(--border-color);background:#0000000d}.btn-secondary:hover{background:#0000001a}.btn-back{border:1px solid var(--border-color);color:var(--text-primary);cursor:pointer;background:#ffffff0d;border-radius:8px;justify-content:center;align-items:center;gap:.5rem;width:max-content;padding:.5rem 1.25rem;font-size:.95rem;font-weight:500;text-decoration:none;transition:all .2s;display:inline-flex}.btn-back:hover{background:#ffffff1a;border-color:#fff3}.link{color:var(--accent-primary);font-weight:500;text-decoration:none;transition:color .3s}.link:hover{color:var(--accent-secondary)}.backend-note{background:var(--bg-primary);border:1px solid var(--border-color);border-left:4px solid var(--accent-secondary);color:var(--text-secondary);border-radius:8px;margin-top:1.5rem;padding:1rem;font-size:.85rem}.backend-note strong{color:var(--accent-secondary)}[data-theme=dark] .form-input{background:#ffffff08}[data-theme=dark] .form-input:focus,[data-theme=dark] .btn-secondary{background:#ffffff0d}[data-theme=dark] .btn-secondary:hover{background:#ffffff1a}[data-theme=light] .btn-back{background:#0000000d}[data-theme=light] .btn-back:hover{background:#0000001a;border-color:#0003}.dropdown-menu{z-index:50;background-color:var(--bg-secondary);border:1px solid var(--border-color);border-radius:8px;min-width:200px;padding:.5rem 0;position:absolute;top:100%;right:1rem;overflow:hidden;box-shadow:0 10px 15px -3px #0000001a,0 4px 6px -2px #0000000d}.dropdown-item{text-align:left;cursor:pointer;width:100%;color:var(--text-primary);background:0 0;border:none;align-items:center;gap:.75rem;padding:.75rem 1rem;font-size:.9rem;font-weight:500;transition:all .2s;display:flex}.dropdown-item:hover{background-color:#00000008}[data-theme=dark] .dropdown-item:hover{background-color:#ffffff0d}.dropdown-item.danger{color:var(--error)}.dropdown-item.danger:hover{background-color:#ef44441a}.dropdown-item.success{color:var(--accent-primary)}.dropdown-item.success:hover{background-color:rgba(var(--accent-primary-rgb), .1)}.dropdown-item.warning{color:#f59e0b}.dropdown-item.warning:hover{background-color:#f59e0b1a}.app-container{background-color:var(--bg-primary);flex-direction:column;height:100dvh;display:flex;overflow:hidden}.mobile-topbar{height:var(--topbar-height);background-color:var(--bg-secondary);border-bottom:1px solid var(--border-color);z-index:50;flex-shrink:0;justify-content:space-between;align-items:center;padding:0 1rem;display:flex;position:sticky;top:0}.sidebar{width:var(--sidebar-width);background-color:var(--bg-secondary);border-right:1px solid var(--border-color);z-index:100;flex-direction:column;padding:1.5rem 1rem;transition:transform .3s cubic-bezier(.4,0,.2,1);display:flex;position:fixed;top:0;bottom:0;left:0;overflow-y:auto;transform:translate(-100%)}.sidebar.is-open{transform:translate(0)}.sidebar-overlay{z-index:90;opacity:0;pointer-events:none;-webkit-backdrop-filter:blur(2px);backdrop-filter:blur(2px);background-color:#00000080;transition:opacity 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button{width:100%!important}}.footer-grid{z-index:1;grid-template-columns:1.5fr 1fr 2fr 1.2fr;gap:3rem;display:grid;position:relative}@media (width<=1024px){.footer-grid{grid-template-columns:1fr 1fr;gap:2rem}}@media (width<=768px){.footer-grid{grid-template-columns:1fr;gap:2.5rem}}@media (width<=640px){.footer-sub{text-align:center;flex-direction:column!important;gap:1.5rem!important}}