*,:after,:before{box-sizing:border-box;margin:0;padding:0}:root{--font-sans:"Inter",system-ui,-apple-system,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;--font-display:"Libre Baskerville",Georgia,"Times New Roman",serif;--font-mono:"JetBrains Mono",ui-monospace,SFMono-Regular,"SF Mono",Menlo,Consolas,monospace;--text-xs:0.75rem;--text-sm:0.875rem;--text-base:1rem;--text-md:1.25rem;--text-lg:1.125rem;--text-xl:1.25rem;--text-2xl:1.5rem;--text-3xl:1.875rem;--text-display:3.5rem;--gray-50:#f9fafb;--gray-100:#f3f4f6;--gray-200:#e5e7eb;--gray-300:#d1d5db;--gray-400:#9ca3af;--gray-500:#6b7280;--gray-600:#4b5563;--gray-700:#374151;--gray-800:#1f2937;--gray-900:#111827;--blue-50:#eff6ff;--blue-100:#dbeafe;--blue-500:#3b82f6;--blue-600:#2563eb;--blue-700:#1d4ed8;--text-primary:#1c1917;--text-primary-subdued:#44403c;--text-secondary:#6b6560;--text-body:#1a1a1a;--text-on-dark:#ffffff;--surface-hero:#efede8;--surface-button-glass:rgba(26,26,26,0.6);--surface-button-glass-hover:rgba(26,26,26,0.75);--border-subtle:#e0ddd7;--surface-card-default:#edecea;--surface-card-active:#5c5650;--surface-quote:#504b47;--surface-cta-tooltip:#1a1a1a;--text-on-quote:#ffffff;--text-quote-muted:#c4c0b8;--text-title-default:#2c2925;--text-title-active:#edecea;--text-body-default:#3d3b38;--text-body-faded:#9c9892;--text-body-faded-active:rgba(237,236,234,0.55);--text-list-default:#3d3b38;--text-list-active:#dedad5;--border-divider:#c8c4be;--border-divider-active:rgba(237,236,234,0.22);--color-text:var(--gray-900);--color-text-secondary:var(--gray-500);--color-text-muted:var(--gray-400);--color-bg:#ffffff;--color-bg-subtle:var(--gray-50);--color-border:var(--gray-200);--color-border-light:var(--gray-100);--color-link:var(--blue-600);--color-link-hover:var(--blue-700);--color-accent:var(--blue-600);--color-success:#16a34a;--color-success-bg:#f0fdf4;--color-success-border:#bbf7d0;--color-warning:#ca8a04;--color-warning-bg:#fefce8;--color-warning-border:#fef08a;--color-error:#dc2626;--color-error-bg:#fef2f2;--color-error-border:#fecaca;--color-info:#2563eb;--color-info-bg:#eff6ff;--color-info-border:#bfdbfe;--space-1:0.25rem;--space-2:0.5rem;--space-3:0.75rem;--space-4:1rem;--space-5:1.25rem;--space-6:1.5rem;--space-8:2rem;--space-10:2.5rem;--space-12:3rem;--space-14:3.5rem;--space-16:4rem;--radius-sm:4px;--radius-md:6px;--radius-lg:8px;--radius-xl:12px;--shadow-sm:0 1px 2px 0 rgb(0 0 0/0.05);--shadow-md:0 4px 6px -1px rgb(0 0 0/0.1),0 2px 4px -2px rgb(0 0 0/0.1);--sidebar-width:260px;--chapter-sidebar-width:388px;--max-content-width:1200px;--hero-max-width:1440px;--hero-padding-x:var(--space-6);--header-height:3.5rem;--app-chrome-bar-height:3.5rem;--app-chrome-height:var(--app-chrome-bar-height);--app-menu-width:345px;--safe-area-top:env(safe-area-inset-top,0px);--safe-area-right:env(safe-area-inset-right,0px);--safe-area-bottom:env(safe-area-inset-bottom,0px);--safe-area-left:env(safe-area-inset-left,0px);--app-chrome-total-height:calc(var(--app-chrome-bar-height) + var(--safe-area-top));--app-menu-inset-top:calc(14px + var(--safe-area-top));--app-menu-inset-left:calc(15px + var(--safe-area-left));--app-menu-inset-bottom:calc(16px + var(--safe-area-bottom));--surface-page:#faf8f3;--surface-callout:#4a4642;--surface-chip-active:#e0ddd7;--some-feedback-page:#faf7f2;--some-feedback-card:#ffffff;--some-feedback-text:#1a1a1a;--some-feedback-text-muted:#666666;--some-feedback-acceptable:#fdb813;--some-feedback-acceptable-bg:#fff9e6;--some-feedback-improve:#e51d4f;--some-feedback-improve-bg:#fff0f3;--fb-text:#050505;--fb-text-muted:#65676b;--fb-bubble:#f2f3f5;--fb-link:#1877f2;--fb-bg-subtle:#f7f8fa;--fb-border:#e4e6eb;--quiz-correct-text:#047857;--quiz-correct-border:#047857;--quiz-correct-bg:#ecfdf5;--quiz-incorrect-text:#be123c;--quiz-incorrect-border:#be123c;--quiz-incorrect-bg:#fff1f2;--quiz-feedback-incorrect-title:#be123c;--quiz-feedback-incorrect-border:#fecdd3;--quiz-feedback-incorrect-bg:#fff1f2;--quiz-feedback-correct-title:#047857;--quiz-feedback-correct-border:#a7f3d0;--quiz-feedback-correct-bg:#ecfdf5;--quiz-neutral-text:#9ca3af;--quiz-neutral-border:#e5e7eb}@media (max-width:720px){:root{--text-display:1.75rem;--text-3xl:1.5rem;--text-2xl:1.25rem}}html{font-size:16px;-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale;text-rendering:optimizeLegibility;scrollbar-gutter:stable}body{font-family:var(--font-sans);font-size:var(--text-base);line-height:1.6;color:var(--text-primary);background:var(--surface-page)}h1,h2,h3,h4,h5,h6{line-height:1.3;font-weight:600;color:var(--gray-900)}h1{font-size:var(--text-3xl)}h2{font-size:var(--text-2xl)}h3{font-size:var(--text-xl)}h4{font-size:var(--text-lg)}p{margin-bottom:1rem;line-height:1.7}a{color:var(--color-link);text-decoration:none;transition:color .15s ease}a:hover{color:var(--color-link-hover);text-decoration:underline}img,video{max-width:100%;height:auto;display:block}[type=button],[type=submit],button{font-family:inherit;font-size:var(--text-sm);font-weight:500;line-height:1;padding:.5rem 1rem;border:1px solid var(--color-border);border-radius:var(--radius-md);background:var(--color-bg);color:var(--color-text);cursor:pointer;transition:all .15s ease}[type=button]:hover,[type=submit]:hover,button:hover{background:var(--gray-50);border-color:var(--gray-300)}[type=button]:active,[type=submit]:active,button:active{background:var(--gray-100)}button:disabled{opacity:.5;cursor:not-allowed}.btn-primary{background:var(--color-accent);color:#fff;border-color:var(--color-accent)}.btn-primary:hover{background:var(--blue-700);border-color:var(--blue-700)}table{width:100%;border-collapse:collapse;font-size:var(--text-sm)}td,th{padding:.625rem .875rem;text-align:left;border-bottom:1px solid var(--color-border)}thead th{font-weight:600;color:var(--gray-700);border-bottom:2px solid var(--color-border)}tbody tr:hover,thead th{background:var(--gray-50)}::-webkit-scrollbar{width:6px;height:6px}::-webkit-scrollbar-track{background:transparent}::-webkit-scrollbar-thumb{background:var(--gray-300);border-radius:3px}::-webkit-scrollbar-thumb:hover{background:var(--gray-400)}