/* System One experiments. Shared by every page in docs/.
   A neutral, Linear-style light theme: white surfaces, cool grays, hairline borders, one indigo accent. */

:root {
  color-scheme: light;
  --paper: #fbfbfc;
  --surface: #ffffff;
  --surface-2: #f4f5f7;
  --ink: #16171b;
  --ink-2: #5b5e69;
  --muted: #8a8e99;
  --rule: #e8e9ed;
  --rule-strong: #d8dae0;
  --grid: rgba(22, 23, 27, 0.04);
  --highlight: rgba(94, 106, 210, 0.14);
  --stamp: #5e6ad2; /* the accent */
  --accent-ink: #4b56bd;
  --link: #4b56bd;
  --shadow: 0 1px 1px rgba(16, 18, 27, 0.02), 0 2px 6px rgba(16, 18, 27, 0.04);
  --shadow-lg: 0 1px 2px rgba(16, 18, 27, 0.04), 0 12px 32px -12px rgba(16, 18, 27, 0.14);

  /* Decision models: categorical slots 1-3 (validated all-pairs, both modes). */
  --m-typesafe: #2a78d6;
  --m-flash: #eb6834;
  --m-27b: #1baf7a;

  /* Routes: one ordinal gray ramp, cheapest (lightest) to most capable. */
  --r-0: #adb1bc;
  --r-1: #777c8a;
  --r-2: #363944;
  --r-ink-0: #16171b;
  --r-ink-1: #ffffff;
  --r-ink-2: #ffffff;

  /* Status, always with an icon and a word. */
  --good: #0ca30c;
  --good-text: #1a7f37;
  --warning: #e5a000;
  --warning-text: #9a6700;
  --critical: #d03b3b;

  --serif: "Inter", system-ui, -apple-system, "Segoe UI", sans-serif; /* display role: Inter Display via opsz */
  --sans: "Inter", system-ui, -apple-system, "Segoe UI", sans-serif;
  --mono: "JetBrains Mono", ui-monospace, "SFMono-Regular", Menlo, monospace;

  --measure: 66ch;
  --wide: 1120px;
  --gutter: 16px;
  --radius: 10px;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    color-scheme: dark;
    --paper: #0b0c0e;
    --surface: #141517;
    --surface-2: #1b1c1f;
    --ink: #f4f5f6;
    --ink-2: #b2b5bd;
    --muted: #7f838d;
    --rule: #25262a;
    --rule-strong: #34363b;
    --grid: rgba(255, 255, 255, 0.03);
    --highlight: rgba(124, 134, 232, 0.2);
    --stamp: #7c86e8;
    --accent-ink: #a3abf2;
    --link: #a3abf2;
    --shadow: 0 1px 2px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 16px 40px -12px rgba(0, 0, 0, 0.6);
    --m-typesafe: #3987e5;
    --m-flash: #d95926;
    --m-27b: #199e70;
    --r-0: #4b4e59;
    --r-1: #8a8e9b;
    --r-2: #d6d8df;
    --r-ink-0: #ffffff;
    --r-ink-1: #0b0c0e;
    --r-ink-2: #0b0c0e;
    --good-text: #3fb950;
    --warning-text: #d29922;
  }
}
:root[data-theme="dark"] {
  color-scheme: dark;
  --paper: #0b0c0e;
  --surface: #141517;
  --surface-2: #1b1c1f;
  --ink: #f4f5f6;
  --ink-2: #b2b5bd;
  --muted: #7f838d;
  --rule: #25262a;
  --rule-strong: #34363b;
  --grid: rgba(255, 255, 255, 0.03);
  --highlight: rgba(124, 134, 232, 0.2);
  --stamp: #7c86e8;
  --accent-ink: #a3abf2;
  --link: #a3abf2;
  --shadow: 0 1px 2px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 16px 40px -12px rgba(0, 0, 0, 0.6);
  --m-typesafe: #3987e5;
  --m-flash: #d95926;
  --m-27b: #199e70;
  --r-0: #4b4e59;
  --r-1: #8a8e9b;
  --r-2: #d6d8df;
  --r-ink-0: #ffffff;
  --r-ink-1: #0b0c0e;
  --r-ink-2: #0b0c0e;
  --good-text: #3fb950;
  --warning-text: #d29922;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: 72px;
}
@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.6;
  font-optical-sizing: auto;
  font-feature-settings: "cv11", "ss01";
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

/* Hero backdrop: a faint grid fading out, with a soft accent glow. */
.graph-paper {
  position: relative;
  background:
    radial-gradient(60% 50% at 50% 0%, color-mix(in srgb, var(--stamp) 9%, transparent), transparent 70%),
    var(--surface);
}
.graph-paper::before {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background-image:
    linear-gradient(var(--grid) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid) 1px, transparent 1px);
  background-size: 32px 32px;
  mask-image: radial-gradient(70% 80% at 50% 0%, #000 30%, transparent 75%);
  -webkit-mask-image: radial-gradient(70% 80% at 50% 0%, #000 30%, transparent 75%);
}
.graph-paper > * {
  position: relative;
}

a {
  color: var(--link);
  text-decoration: none;
}
a:hover {
  text-decoration: underline;
  text-underline-offset: 3px;
}

h1,
h2,
h3 {
  font-weight: 600;
  line-height: 1.12;
  letter-spacing: -0.02em;
  margin: 0 0 0.5em;
  color: var(--ink);
}
h1 {
  font-size: clamp(2.4rem, 5.6vw, 4rem);
  letter-spacing: -0.035em;
  line-height: 1.04;
}
h2 {
  font-size: clamp(1.6rem, 3.2vw, 2.15rem);
  letter-spacing: -0.028em;
}
h3 {
  font-size: 1.12rem;
  letter-spacing: -0.012em;
}
p {
  margin: 0 0 1em;
}
em {
  font-style: normal;
  color: var(--ink);
  font-weight: 500;
}
code,
kbd {
  font-family: var(--mono);
  font-size: 0.85em;
  background: var(--surface-2);
  border: 1px solid var(--rule);
  border-radius: 5px;
  padding: 0.08em 0.35em;
}
pre {
  font-family: var(--mono);
  font-size: 0.8rem;
  line-height: 1.55;
  background: var(--surface);
  border: 1px solid var(--rule);
  border-radius: var(--radius);
  padding: 16px;
  overflow-x: auto;
  margin: 0 0 1.2em;
}
pre code {
  background: none;
  border: 0;
  padding: 0;
  font-size: inherit;
}
mark {
  background: var(--highlight);
  color: inherit;
  border-radius: 4px;
  padding: 0 3px;
  box-decoration-break: clone;
  -webkit-box-decoration-break: clone;
}

.wrap {
  max-width: var(--wide);
  margin: 0 auto;
  padding: 0 var(--gutter);
}
.prose {
  max-width: var(--measure);
}

/* Small quiet labels for metadata. */
.label {
  font-family: var(--sans);
  font-size: 0.75rem;
  font-weight: 500;
  letter-spacing: 0;
  color: var(--muted);
}
.eyebrow {
  display: inline-flex;
  gap: 8px;
  align-items: center;
  margin-bottom: 22px;
  padding: 4px 12px 4px 8px;
  border: 1px solid var(--rule);
  border-radius: 999px;
  background: var(--surface);
  box-shadow: var(--shadow);
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--ink-2);
}
.eyebrow .dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--stamp);
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--stamp) 20%, transparent);
}

/* Top bar */
.topbar {
  position: sticky;
  top: 0;
  z-index: 20;
  background: color-mix(in srgb, var(--surface) 80%, transparent);
  backdrop-filter: saturate(180%) blur(12px);
  -webkit-backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--rule);
}
.topbar .wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  height: 52px;
}
.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--ink);
  text-decoration: none;
  font-family: var(--sans);
  font-size: 0.875rem;
  font-weight: 600;
  letter-spacing: -0.01em;
  white-space: nowrap;
}
.brand svg {
  flex: none;
}
.brand .crumb {
  color: var(--muted);
  font-weight: 500;
}
.topbar nav {
  display: flex;
  align-items: center;
  gap: 4px;
  font-family: var(--sans);
  font-size: 0.82rem;
  font-weight: 500;
}
.topbar nav a {
  color: var(--ink-2);
  text-decoration: none;
  padding: 5px 10px;
  border-radius: 6px;
}
.topbar nav a:hover {
  color: var(--ink);
  background: var(--surface-2);
}
.theme-toggle {
  appearance: none;
  border: 1px solid var(--rule);
  background: var(--surface);
  color: var(--ink-2);
  width: 30px;
  height: 30px;
  margin-left: 6px;
  border-radius: 7px;
  box-shadow: var(--shadow);
  display: grid;
  place-items: center;
  cursor: pointer;
}
.theme-toggle:hover {
  color: var(--ink);
}
@media (max-width: 640px) {
  .topbar nav .hide-sm {
    display: none;
  }
  .topbar nav a {
    padding: 5px 6px;
  }
}

/* Section scaffolding */
section {
  padding: 88px 0;
}
section + section {
  border-top: 1px solid var(--rule);
}
.sec-head {
  display: block;
  margin-bottom: 32px;
}
.sec-num {
  display: inline-block;
  font-family: var(--mono);
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--stamp);
  margin-bottom: 12px;
}
.sec-head h2 {
  margin-bottom: 0.4em;
}
.sec-head .lede {
  color: var(--ink-2);
  font-size: 1.05rem;
  max-width: var(--measure);
  margin: 0;
}
@media (max-width: 640px) {
  section {
    padding: 60px 0;
  }
}

/* Cards and panels */
.card {
  background: var(--surface);
  border: 1px solid var(--rule);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 20px;
}
.figure {
  background: var(--surface);
  border: 1px solid var(--rule);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 20px;
  margin: 0 0 12px;
}
.figcap {
  font-family: var(--sans);
  font-size: 0.8rem;
  color: var(--muted);
  line-height: 1.5;
  margin: 8px 0 28px;
  max-width: var(--measure);
}
.figcap b {
  font-weight: 600;
  color: var(--ink-2);
  margin-right: 6px;
}

/* Status badge: a dot and a word. */
.stamp {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-family: var(--sans);
  font-size: 0.75rem;
  font-weight: 500;
  line-height: 1;
  color: var(--ink-2);
  background: var(--surface);
  border: 1px solid var(--rule);
  border-radius: 999px;
  padding: 5px 9px;
  white-space: nowrap;
}
.stamp::before {
  content: "";
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--warning);
}
.stamp.live::before {
  background: var(--good);
}
.stamp.idle::before {
  background: var(--rule-strong);
  box-shadow: inset 0 0 0 1.5px var(--muted);
}

/* Tables */
.table-wrap {
  overflow-x: auto;
  border: 1px solid var(--rule);
  border-radius: var(--radius);
  background: var(--surface);
  box-shadow: var(--shadow);
}
table {
  border-collapse: collapse;
  width: 100%;
  font-family: var(--sans);
  font-size: 0.85rem;
}
th,
td {
  text-align: left;
  padding: 10px 12px;
  border-bottom: 1px solid var(--rule);
  vertical-align: top;
}
th {
  font-weight: 500;
  font-size: 0.75rem;
  color: var(--muted);
  background: var(--surface-2);
}
tr:last-child td {
  border-bottom: 0;
}
td.num,
th.num {
  text-align: right;
  font-variant-numeric: tabular-nums;
}

/* Buttons and controls */
.btn {
  appearance: none;
  font-family: var(--sans);
  font-size: 0.8rem;
  font-weight: 500;
  border: 1px solid var(--rule);
  background: var(--surface);
  color: var(--ink-2);
  border-radius: 7px;
  padding: 6px 11px;
  cursor: pointer;
  line-height: 1.25;
  box-shadow: var(--shadow);
  text-decoration: none;
  display: inline-block;
}
.btn:hover {
  color: var(--ink);
  background: var(--surface-2);
  text-decoration: none;
}
.btn[aria-pressed="true"] {
  background: color-mix(in srgb, var(--stamp) 10%, var(--surface));
  color: var(--accent-ink);
  border-color: color-mix(in srgb, var(--stamp) 40%, transparent);
}
.btn:focus-visible,
a:focus-visible,
input:focus-visible,
select:focus-visible,
.theme-toggle:focus-visible {
  outline: 2px solid var(--link);
  outline-offset: 2px;
}

/* Footer */
footer.site {
  border-top: 1px solid var(--rule);
  background: var(--surface);
  padding: 32px 0 48px;
  font-size: 0.8rem;
  color: var(--muted);
}
footer.site .wrap {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 12px;
}
footer.site a {
  color: var(--ink-2);
}

/* Reveal on scroll */
.reveal {
  opacity: 0;
  transform: translateY(14px);
  transition:
    opacity 0.6s ease,
    transform 0.6s ease;
}
.reveal.in {
  opacity: 1;
  transform: none;
}
@media (prefers-reduced-motion: reduce) {
  .reveal {
    opacity: 1;
    transform: none;
    transition: none;
  }
}

.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;
}