:root{font-family:Arial,Helvetica,sans-serif;font-synthesis:none}
*{box-sizing:border-box}html{scroll-padding-top:100px}body{margin:0;background:var(--bg);color:var(--fg)}a{color:inherit;text-decoration-color:var(--control-border);text-underline-offset:4px}a:hover{text-decoration-color:var(--fg)}button,input{font:inherit}button,summary,input[type=radio],input[type=range]{cursor:pointer}button{border:1px solid var(--control-border);border-radius:3px;color:var(--fg);background:transparent;padding:11px 17px;min-height:44px}button:hover{background:var(--wash)}button:disabled,button[aria-disabled=true]{opacity:.55;cursor:default}button.primary,.start-link{background:var(--fg);color:var(--bg);border-color:var(--fg)}:focus-visible{outline:2px solid var(--fg);outline-offset:5px}::selection{background:var(--ink);color:var(--paper)}[hidden]{display:none!important}
.skip-link{position:fixed;left:20px;top:-80px;background:var(--fg);color:var(--bg);padding:14px;z-index:20}.skip-link:focus{top:10px}.site-header{height:72px;display:flex;align-items:center;justify-content:space-between;padding:0 32px;border-bottom:1px solid var(--line);position:sticky;top:0;background:var(--bg);z-index:10;gap:20px}.brand{font:700 22px Georgia,serif;text-decoration:none;white-space:nowrap}.brand-mark{display:inline-block;width:19px;height:19px;border:1px solid currentColor;border-radius:50%;margin-right:11px;position:relative;top:3px}.brand-mark:after{content:'';position:absolute;inset:4px;border-left:1px solid currentColor;transform:rotate(45deg)}.header-center{text-align:center;font-size:12px;color:var(--muted);line-height:1.6}.progress-ticks{display:flex;gap:5px;margin-top:5px}.progress-ticks a{height:3px;width:30px;background:var(--line)}.progress-ticks a[aria-current=page]{background:var(--fg)}.header-links{display:flex;gap:22px;font-size:13px;align-items:center}.header-links a{text-decoration:none}.book-menu{position:relative}.book-menu summary{list-style:none;border:1px solid var(--line);padding:10px 13px;border-radius:3px;min-height:38px}.book-menu summary::-webkit-details-marker{display:none}.book-menu nav{position:absolute;right:0;top:45px;width:290px;background:var(--paper);border:1px solid var(--control-border);padding:16px;box-shadow:0 20px 50px var(--shadow-color);max-height:75vh;overflow:auto}.book-menu nav a{display:block;padding:12px 4px;line-height:1.5}.book-menu nav a[aria-current=page]{font-weight:bold;text-decoration:underline}
.chapter-rail{position:fixed;left:28px;top:125px;width:195px;font-size:12px}.rail-label,.eyebrow{font-size:11px;letter-spacing:.12em;text-transform:uppercase;color:var(--muted)}.chapter-rail ol{list-style:none;padding:0;margin:22px 0}.chapter-rail li{margin:0 0 18px}.chapter-rail a{display:flex;gap:12px;color:var(--muted);text-decoration:none;line-height:1.55}.chapter-rail a[aria-current=page]{color:var(--fg)}.chapter-rail .number{font-size:11px;min-width:15px}.chapter-rail .current-dot{width:4px;height:4px;background:var(--fg);border-radius:50%;margin-top:7px}.reading-shell{max-width:740px;margin:0 auto;padding:62px 28px 60px}.chapter-heading .breadcrumb{font-size:12px;color:var(--muted);margin-bottom:26px}.breadcrumb a{text-decoration:none}.chapter-number{font:italic 23px Georgia,serif;color:var(--quiet);margin:0 0 8px}h1,h2,h3,p,figure{margin-top:0}h1{font:normal clamp(36px,4.2vw,54px)/1.12 Georgia,'Times New Roman',serif;letter-spacing:-.035em;margin-bottom:25px}h2{font:normal 29px/1.25 Georgia,serif;letter-spacing:-.025em;margin:48px 0 20px}h3{font:normal 23px/1.3 Georgia,serif;margin:32px 0 16px}.dek{font:21px/1.65 Georgia,serif;color:var(--quiet);margin:0 0 30px}.in-this-chapter{border-top:1px solid var(--line);border-bottom:1px solid var(--line);padding:18px 0;margin:32px 0 40px;font-size:13px;line-height:1.8;display:flex;gap:22px}.in-this-chapter>span{color:var(--muted);flex-shrink:0}.in-this-chapter ul{padding:0;list-style:none;display:flex;flex-wrap:wrap;gap:3px 20px;margin:0}.in-this-chapter a{text-decoration:none}.prose p,.prose li,.prose blockquote,.prose dd{font:19px/1.78 Georgia,'Times New Roman',serif}.prose p{margin-bottom:23px}.prose ul,.prose ol{padding-left:24px}.prose li{padding-left:4px;margin:9px 0}.prose blockquote{border-left:2px solid var(--control-border);padding:2px 0 2px 24px;margin:26px 0;color:var(--fg)}.prose blockquote p{margin:0}.prose strong{font-weight:700;color:var(--strong)}.prose code{font: .82em ui-monospace,Consolas,monospace;background:var(--wash);padding:2px 5px;border-radius:2px;overflow-wrap:anywhere}.prose .source-note,.prose .source-note p,.source-note{font:12px/1.7 Arial,sans-serif;color:var(--muted)}.source-note a{text-decoration-color:var(--control-border)}.source-note{margin-top:12px}.math-display{overflow-x:auto;overflow-y:hidden;padding:12px 0;margin:20px 0;font-size:1.05em}.katex-display{margin:.4em 0!important}.katex{font-size:1.06em!important}.math-display .katex{font-size:1.15em!important}.math-inline{white-space:nowrap}.prose .check,.prose details{border-top:1px solid var(--line);margin:28px 0;padding-top:18px}.prose summary{font:14px/1.6 Arial,sans-serif;padding:9px 0;min-height:44px}.prose details p{font-size:17px}.prose details>div{padding:14px 0}.chapter-next{display:grid;grid-template-columns:1fr 1fr;gap:28px;border-top:1px solid var(--line);margin-top:55px;padding-top:27px}.chapter-next a{text-decoration:none;font:18px/1.5 Georgia,serif}.chapter-next small{display:block;font:11px Arial,sans-serif;color:var(--muted);text-transform:uppercase;letter-spacing:.08em;margin-bottom:8px}.chapter-next a:last-child{text-align:right}.chapter-next a:hover{text-decoration:underline}.chapter-footer{margin-top:40px;font-size:11px;color:var(--muted);line-height:1.8}.table-wrap{overflow-x:auto;max-width:100%}table{border-collapse:collapse;width:100%;font:13px/1.5 Arial,sans-serif;margin:24px 0}th,td{border-bottom:1px solid var(--line);text-align:left;padding:13px 10px;vertical-align:top}th{font-weight:normal;color:var(--muted)}td:first-child,th:first-child{padding-left:0}caption{text-align:left;color:var(--muted);font-size:12px;margin-bottom:12px}
.wide-figure{width:calc(100% + 110px);margin:36px -55px;border-top:1px solid var(--line);border-bottom:1px solid var(--line);padding:20px 25px 21px;background:var(--bg)}.figure-top{font:12px/1.5 Arial,sans-serif;display:flex;gap:16px;margin-bottom:22px;color:var(--muted)}.figure-top strong{font-weight:normal;color:var(--fg)}.diagram{display:block;width:100%;height:auto;overflow:visible;color:var(--fg)}.diagram text{fill:currentColor;font:16px Arial,sans-serif;stroke:none}.diagram line,.diagram path{stroke:currentColor;stroke-width:1;fill:none}.diagram circle{fill:var(--fg);stroke:var(--fg);stroke-width:1}.diagram .svg-kicker{font-size:11px;letter-spacing:.07em;fill:var(--muted)}.diagram .svg-muted{font-size:13px;fill:var(--muted)}.diagram .svg-emphasis{font-size:15px;fill:var(--fg)}.diagram .svg-value{font-size:13px;fill:var(--fg)}.diagram .grid-line{stroke:var(--grid)}.diagram .row-guide{stroke:var(--line)}.diagram .mean-line{stroke:var(--fg);stroke-dasharray:4 5;opacity:.7}.diagram .distance-line{stroke-width:2}.diagram .focus-dot{fill:var(--bg);stroke:var(--fg);stroke-width:1.5}.diagram .prompt-ribbon{fill:var(--wash);stroke:none}.diagram .token-ribbon{fill:var(--figure-subtle);stroke:none}.compact-diagram{display:none}figcaption{font:12px/1.7 Arial,sans-serif;color:var(--muted);margin-top:15px;max-width:690px}.home-shell{max-width:820px;margin:0 auto;padding:65px 32px 80px}.home-shell h1{font-size:64px;margin-top:24px}.home-shell .dek{max-width:600px}.start-link{display:inline-block;padding:12px 19px;text-decoration:none;font-size:13px;margin:0 14px 8px 0;border-radius:2px}.continue-link{font-size:12px;color:var(--muted)}.home-list{margin-top:46px;border-top:1px solid var(--line)}.home-list a{display:grid;grid-template-columns:32px 1fr 24px;gap:16px;text-decoration:none;padding:23px 0;border-bottom:1px solid var(--line)}.home-list .chapter-name{font:24px Georgia,serif}.home-list .chapter-sub{display:block;font:13px/1.6 Arial,sans-serif;color:var(--muted);margin-top:9px}.home-list .number{font-size:12px;color:var(--muted);padding-top:5px}.home-list .arrow{padding-top:5px}.home-list a:hover .chapter-name{text-decoration:underline;text-underline-offset:5px}.home-note{font:13px/1.8 Arial,sans-serif;color:var(--muted);margin:30px 0}.home-shell .wide-figure{width:100%;margin:38px 0 0;padding-left:0;padding-right:0}.appendix dl{margin:30px 0}.appendix dt{font:21px Georgia,serif;margin-top:25px}.appendix dd{margin:9px 0 25px;color:var(--quiet)}.appendix .source-index{font-size:13px;line-height:1.7;overflow-wrap:anywhere}
.lab{margin-top:25px}.lab .boundary{font:12px/1.6 Arial,sans-serif;color:var(--muted);border-left:2px solid var(--control-border);padding-left:14px;margin:18px 0 25px}.prediction{border:0;border-bottom:1px solid var(--line);padding:0 0 24px;margin:0 0 24px}.prediction legend{font:20px/1.5 Georgia,serif;margin-bottom:15px}.prediction label{display:flex;align-items:center;gap:10px;font:14px/1.6 Arial,sans-serif;min-height:42px}.prediction input{accent-color:var(--ink);width:17px;height:17px}.prediction button{margin-top:17px}.prediction-feedback{font:15px/1.7 Arial,sans-serif!important;margin-top:18px}.lab-controls{display:grid;grid-template-columns:1fr 1fr auto;gap:24px;align-items:center}.lab-controls label{display:flex;justify-content:space-between;font-size:13px;gap:12px}.lab-controls input{width:100%;accent-color:var(--ink);min-height:44px;margin:3px 0 0}.lab-controls small{font-size:11px;color:var(--muted)}.lab .wide-figure{margin-top:26px}.lab .plot-interpretation{font:18px/1.6 Georgia,serif;margin-top:18px}.lab-meta{font:12px/1.7 Arial,sans-serif!important;color:var(--muted)}.lab .numbers-table{font-size:12px}.lab pre,pre{max-width:100%;overflow-x:auto;background:var(--lab-surface);border:1px solid var(--line);padding:18px;font:13px/1.7 ui-monospace,Consolas,monospace}.lab pre code{background:none;padding:0;font:inherit}.js .static-fallback{display:none}.no-script-note{font:13px/1.6 Arial,sans-serif;color:var(--muted)}.snapshot-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:16px}.snapshot-grid>div{border-left:1px solid var(--line);padding-left:18px}.snapshot-grid strong{font:22px Georgia,serif}.snapshot-grid p{font:14px/1.7 Arial,sans-serif}.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}.print-chapter{break-before:page}
.interactive-only{display:none}.js .interactive-only{display:block}.self-check{border-left:2px solid var(--control-border);padding:2px 0 2px 22px;margin:35px 0}.prose .self-check .eyebrow{font:11px Arial,sans-serif;letter-spacing:.1em;margin:8px 0 15px}.prose .chapter-bridge{font-style:italic;color:var(--muted);margin-top:32px}.prose .boundary-note{border-left:2px solid var(--control-border);padding-left:18px}.table-scroll{max-width:100%;overflow-x:auto}.math-inline{display:inline-block;max-width:100%;vertical-align:middle;overflow-x:auto;overflow-y:hidden}.diagram .focus-dot{fill:none}.prose .eyebrow{font:11px Arial,sans-serif}
@media(min-width:1250px){.reading-shell{margin-left:calc(50% - 280px)}}
@media(max-width:1199px){.chapter-rail{display:none}}
@media(max-width:850px){.wide-figure{width:100%;margin:32px 0;padding:20px 0}.reading-shell{padding-top:38px}.site-header{padding:0 20px}}
@media(max-width:600px){.site-header{height:62px;padding:0 16px;gap:8px}.brand{font-size:18px}.brand-mark{width:16px;height:16px;margin-right:7px}.header-center{display:none}.header-links{gap:10px}.header-links>a{display:none}.reading-shell{padding:32px 20px 44px}.home-shell{padding:35px 20px}.home-shell h1{font-size:46px}.dek{font-size:19px}.prose p,.prose li,.prose blockquote{font-size:18px;line-height:1.7}h2{font-size:26px}.in-this-chapter{display:block;margin-top:25px}.in-this-chapter ul{margin-top:10px;display:block}.in-this-chapter li{margin:5px 0}.large-diagram{display:none}.compact-diagram{display:block}.figure-top{display:block}.figure-top strong{display:block;margin-top:8px;font-size:13px}.lab-controls{grid-template-columns:1fr 1fr;gap:16px}.lab-controls button{grid-column:1/-1;justify-self:start}.math-display{font-size:.88em}.snapshot-grid{grid-template-columns:1fr}.home-list .chapter-name{font-size:22px}.home-list a{gap:10px}.chapter-next{gap:20px}.chapter-next a{font-size:16px}.diagram{max-width:100%}.numbers-table th,.numbers-table td{padding:8px 5px}.table-wrap:focus-visible{outline:2px solid var(--fg)}.book-menu nav{width:min(285px,calc(100vw - 32px))}.diagram .svg-muted,.diagram .svg-value{font-size:16px}.diagram .svg-emphasis{font-size:17px}.diagram .svg-kicker{font-size:12px}}
@media(prefers-reduced-motion:reduce){*,*::before,*::after{animation:none!important;transition:none!important;scroll-behavior:auto!important}}
@media(forced-colors:active){.diagram .prompt-ribbon,.diagram .token-ribbon{fill:Canvas;stroke:CanvasText}.diagram text{fill:CanvasText}.diagram circle{fill:CanvasText;stroke:CanvasText}.diagram .focus-dot{fill:Canvas}.diagram line,.diagram path{stroke:CanvasText}.progress-ticks a{background:CanvasText}.start-link,button{border:1px solid ButtonText}}
@media print{ :root{color-scheme:light;--bg:#fff;--paper:#fff;--fg:#111;--muted:#444;--line:#bbb;--strong:#000}body{background:#fff;color:#111}.site-header,.chapter-rail,.in-this-chapter,.chapter-next,.skip-link,.chapter-footer,.lab-controls,.prediction,.interactive-only,.home-actions{display:none!important}.reading-shell,.home-shell{width:100%;max-width:none;margin:0;padding:0}.prose p,.prose li,.prose blockquote{font-size:11pt;line-height:1.55}h1{font-size:30pt}h2{font-size:19pt;break-after:avoid}.dek{font-size:14pt}.wide-figure{width:100%;margin:20px 0;padding:10px 0;break-inside:avoid}.diagram{max-height:270px}.compact-diagram{display:none}.large-diagram{display:block}.diagram .prompt-ribbon{fill:#eee}.diagram .token-ribbon{fill:#ddd}.diagram .grid-line,.diagram .row-guide{stroke:#ccc}.js .static-fallback,.static-fallback{display:block!important}details>*{display:block!important}details{break-inside:avoid}summary{font-weight:bold}pre{white-space:pre-wrap;color:#111;background:#eee}.prose code{color:#111;background:#eee}.math-display{overflow:visible}.print-chapter{break-before:page}.print-chapter:first-child{break-before:auto}a{text-decoration:none}.snapshot-grid{grid-template-columns:repeat(3,1fr)}.home-note{color:#444}.source-index{font-size:9pt}.diagram text{font-size:15px}table{font-size:9pt}.book-print-heading{margin-bottom:25px}}
