/* Distill-style article on white. The few colors come from Chase N.'s photo
   "Rock on the button." (Wikimedia Commons, CC BY-SA 2.0): the stone's red handle
   marks the agent (its body and return line), the house-ring navy marks controls,
   and the pebbled ice and granite color the two floors. */
:root {
    --bg: #ffffff;
    --surface: #ffffff;
    --text: rgba(0, 0, 0, 0.8);
    --text-2: rgba(0, 0, 0, 0.6);
    --text-3: rgba(0, 0, 0, 0.45);
    --hairline: rgba(0, 0, 0, 0.1);
    --grid: rgba(0, 0, 0, 0.08);
    --accent: #3b3b61;        /* blue house ring */
    --accent-ink: #ffffff;
    --series: #870a09;        /* red handle cap */
    --series-dot: rgba(135, 10, 9, 0.28);
    --event: rgba(0, 0, 0, 0.45);
    --viewport-bg: #ffffff;
    --body: #870a09;
    --body-eye: #ffffff;
    --ice: #dcdbe1;           /* white button ice */
    --ice-tint: #c8c8e7;      /* pebble sparkle */
    --rubber: #303432;        /* granite of the stone */
    --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, Cantarell, "Fira Sans", "Helvetica Neue", Arial, sans-serif;
    --mono: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
    --text-col: 648px;
    --page-col: 984px;
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
    margin: 0;
    background: var(--bg);
    color: var(--text);
    font: 17px/1.7 var(--font);
}

a { color: inherit; text-decoration-color: rgba(0, 0, 0, 0.3); text-underline-offset: 2px; }
a:hover { text-decoration-color: currentColor; }

/* Text column (648px) centered with a 16px gutter; figures use the 984px page column */
nav.site, .title, .byline, .prose, .appendix > * {
    max-width: var(--text-col);
    margin-left: auto;
    margin-right: auto;
}

nav.site {
    padding: 14px 16px 0;
    font-size: 13px;
    max-width: var(--page-col);
}

nav.site a { color: var(--text-3); text-decoration: none; }
nav.site a:hover { color: var(--text); }

.title { padding: 56px 16px 28px; }

.title h1 {
    margin: 0 0 12px;
    font-size: clamp(36px, 6vw, 50px);
    line-height: 1.1;
    font-weight: 700;
    color: rgba(0, 0, 0, 0.85);
}

.description {
    margin: 0;
    font-size: 21px;
    line-height: 1.5;
    color: var(--text-2);
}

/* --- Demo: full-width hero, controls and results at page width */

.viewport {
    position: relative;
    width: 100%;
    height: clamp(320px, 62vh, 760px);
    background: var(--viewport-bg);
    border-top: 1px solid var(--hairline);
    border-bottom: 1px solid var(--hairline);
}

#view { display: block; width: 100%; height: 100%; }

.hud {
    position: absolute;
    left: 16px;
    top: 14px;
    font: 13px var(--mono);
    padding: 3px 10px;
    border-radius: 999px;
    background: rgba(255, 255, 255, 0.85);
    color: var(--text);
    border: 1px solid var(--hairline);
}

.status {
    position: absolute;
    inset: 0;
    display: grid;
    place-items: center;
    padding: 16px;
    text-align: center;
    color: var(--text-2);
    font-size: 15px;
}

.status:empty { display: none; }

.panel {
    max-width: var(--page-col);
    margin: 0 auto;
    padding: 14px 16px 0;
}

.controls {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 10px 24px;
    font-size: 14px;
}

.group { display: inline-flex; align-items: center; gap: 10px; }

.label {
    color: var(--text-3);
    font-size: 11px;
    text-transform: uppercase;
    letter-spacing: 0.08em;
}

button {
    font: inherit;
    font-size: 14px;
    padding: 4px 12px;
    border: 1px solid rgba(0, 0, 0, 0.18);
    border-radius: 5px;
    background: var(--surface);
    color: var(--text);
    cursor: pointer;
}

button:hover { border-color: rgba(0, 0, 0, 0.4); }

.segmented { display: inline-flex; }
.segmented button { border-radius: 0; margin-left: -1px; }
.segmented button:first-child { border-radius: 5px 0 0 5px; margin-left: 0; }
.segmented button:last-child { border-radius: 0 5px 5px 0; }
.segmented button[aria-pressed="true"] {
    background: var(--accent);
    border-color: var(--accent);
    color: var(--accent-ink);
    position: relative;
}

.switch { display: inline-flex; align-items: center; gap: 6px; cursor: pointer; }
.switch input { accent-color: var(--accent); width: 15px; height: 15px; }

.results {
    margin-top: 14px;
    display: grid;
    grid-template-columns: minmax(0, 1fr) 210px;
    gap: 20px;
    align-items: end;
}

@media (max-width: 700px) {
    .results { grid-template-columns: minmax(0, 1fr); }
}

.chart-head {
    display: flex;
    flex-wrap: wrap;
    align-items: baseline;
    justify-content: space-between;
    gap: 4px 12px;
}

.chart-title { font-weight: 600; font-size: 13px; color: var(--text); }

.legend { display: inline-flex; gap: 14px; font-size: 12px; color: var(--text-2); }
.legend span::before { content: ''; display: inline-block; vertical-align: middle; margin-right: 6px; }
.legend .dot::before { width: 6px; height: 6px; border-radius: 50%; background: var(--series-dot); }
.legend .line::before { width: 14px; height: 2px; border-radius: 1px; background: var(--series); }

.chart-wrap { position: relative; }
.chart-wrap canvas { display: block; width: 100%; height: 170px; }

.tooltip {
    position: absolute;
    pointer-events: none;
    background: #fff;
    border: 1px solid var(--hairline);
    border-radius: 4px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
    padding: 6px 8px;
    font-size: 12px;
    line-height: 1.45;
    color: var(--text-2);
    white-space: nowrap;
    z-index: 1;
}

.tooltip strong { color: var(--text); font-size: 14px; }
.tooltip .muted { color: var(--text-3); }

.readouts {
    margin: 0;
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    column-gap: 16px;
    border-top: 1px solid var(--hairline);
}

@media (max-width: 700px) {
    .readouts { grid-template-columns: repeat(4, minmax(0, 1fr)); }
}

@media (max-width: 480px) {
    .readouts { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

.readouts div { padding: 7px 0; border-bottom: 1px solid var(--hairline); min-width: 0; }
.readouts dt {
    font-size: 10px;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--text-3);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}
.readouts dd { margin: 0; font: 14px var(--mono); color: var(--text); font-variant-numeric: tabular-nums; white-space: nowrap; }

/* --- Byline, as on Distill: small uppercase labels between hairlines */

.byline {
    margin-top: 36px;
    padding: 12px 16px;
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 12px 24px;
    border-top: 1px solid var(--hairline);
    border-bottom: 1px solid var(--hairline);
    font-size: 13px;
    line-height: 1.5;
}

.byline h3 {
    margin: 0 0 4px;
    font-size: 10px;
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--text-3);
}

.byline p { margin: 0; color: var(--text); }

@media (max-width: 560px) {
    .byline { grid-template-columns: minmax(0, 1fr); }
}

/* --- Article */

.prose { padding: 32px 16px 48px; }

.prose h2 {
    margin: 2.2rem 0 1.2rem;
    padding-bottom: 0.9rem;
    border-bottom: 1px solid var(--hairline);
    font-size: 24px;
    line-height: 1.25;
    font-weight: 600;
    color: rgba(0, 0, 0, 0.85);
}

.prose p { margin: 0 0 1.1em; }

.prose .katex-display { margin: 0.6em 0 1.1em; overflow-x: auto; overflow-y: hidden; padding: 2px 0; }

a.cite {
    color: var(--text-2);
    text-decoration: none;
    font-size: 0.85em;
    white-space: nowrap;
}

a.cite:hover { color: var(--accent); }

button.inline {
    display: inline;
    margin: 0 0.15em;
    padding: 0 9px;
    font-size: 14px;
    background: var(--accent);
    border-color: var(--accent);
    color: var(--accent-ink);
    border-radius: 999px;
}

figure.run { margin: 1.4em 0; }
figure.run .chart-wrap canvas { height: 210px; }
figcaption { font-size: 13px; line-height: 1.5; color: var(--text-2); margin-top: 8px; }

/* --- Appendix */

.appendix {
    border-top: 1px solid var(--hairline);
    padding: 20px 16px 64px;
    color: var(--text-2);
    font-size: 13px;
    line-height: 1.6;
}

/* The appendix has its own 16px gutter, so its children take the text column minus it */
.appendix > * { max-width: calc(var(--text-col) - 32px); }

.appendix h3 {
    margin-top: 22px;
    margin-bottom: 8px;
    font-size: 15px;
    font-weight: 600;
    color: rgba(0, 0, 0, 0.65);
}

.appendix a { color: var(--text-2); }

.refs { padding-left: 1.3em; margin-top: 0; }
.refs li { margin-bottom: 0.5em; }
.refs li:target { background: #fff8d6; }