/* agentstow.dev
 *
 * Structured after vercel.com/design.md — precise, calm, evidence-led,
 * restrained. Three deliberate departures, all because that document is written
 * to establish *Vercel* authorship on Vercel-authored pages:
 *
 *   - Geist is replaced by the platform sans/mono stack. The type *system* —
 *     roles, scale, weights, leading, a 64ch measure — is applied verbatim on
 *     top of it. No webfonts, no build step, no JavaScript: the same discipline
 *     the product follows, and what lets public/_headers declare
 *     `script-src 'none'` honestly.
 *   - "Design in monochrome" is read as a single warm ramp rather than a grey
 *     one. Accent is spent on exactly four things — link text, the one primary
 *     action, the focus ring, and the hairline on the mark — and never on
 *     backgrounds, table cells, or state.
 *   - agentstow has no web UI to inherit a palette from, so the ramp is defined
 *     here and the favicon and og artwork derive from it.
 *
 * Hard rejects honoured literally: no gradients, gradient text, glows, blobs,
 * stripes, textures, grid backgrounds, glass, or ornamental shadows. Default to
 * stillness. Hierarchy through typography first, then surfaces. Code samples
 * are dimmed and weighted, never colour-coded, so they survive greyscale.
 */

:root {
  /* ---- surfaces ---- */
  --as-surface-primary: #faf9f7;
  --as-surface-secondary: #ffffff;
  /* Earned, not decorative: used only where a sample needs to sit apart. */
  --as-surface-emphasis: #f2efe9;

  /* ---- text ---- */
  --as-text-primary: #1b1a18;
  --as-text-secondary: #6a655e;
  --as-text-on-accent: #faf9f7;

  /* ---- borders ---- */
  --as-border-subtle: #eae6de;
  --as-border-default: #e2ddd4;

  /* ---- the one hue ---- */
  --as-accent: #2f6a58;
  --as-focus: #2f6a58;
  --as-color-warning: #8a6d1f;

  /* ---- type ---- */
  --as-font-sans: ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI",
    Roboto, Helvetica, Arial, sans-serif;
  --as-font-mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas,
    "Liberation Mono", monospace;

  --as-type-display: clamp(2rem, 1.35rem + 2.6vw, 2.6rem);
  --as-type-page-title: 1.75rem;
  --as-type-title: 1.35rem;
  --as-type-section: 1.05rem;
  --as-type-body: 1rem;
  --as-type-compact: 0.9375rem;
  --as-type-label: 0.8125rem;

  --as-weight-regular: 400;
  --as-weight-medium: 500;
  --as-weight-heading: 600;

  --as-leading-display: 1.1;
  --as-leading-title: 1.25;
  --as-leading-section: 1.35;
  --as-leading-body: 1.6;

  /* ---- space, on a 4px base ---- */
  --as-space-1: 0.25rem;
  --as-space-2: 0.5rem;
  --as-space-3: 0.75rem;
  --as-space-4: 1rem;
  --as-space-5: 1.25rem;
  --as-space-6: 1.5rem;
  --as-space-8: 2rem;
  --as-space-10: 2.5rem;
  --as-space-12: 3rem;
  --as-space-16: 4rem;

  --as-radius-small: 5px;
  --as-radius: 10px;

  --as-shell: 66rem;
  /* Only the capability matrix uses this: six columns plus a row header need
   * more than the reading shell before horizontal scroll kicks in. */
  --as-shell-wide: 78rem;
  --as-measure: 64ch;
}

@media (prefers-color-scheme: dark) {
  :root {
    --as-surface-primary: #15161a;
    --as-surface-secondary: #1d1f24;
    --as-surface-emphasis: #23252b;
    --as-text-primary: #eae8e3;
    --as-text-secondary: #979289;
    --as-text-on-accent: #15161a;
    --as-border-subtle: #24262d;
    --as-border-default: #303339;
    --as-accent: #7cc0ac;
    --as-focus: #7cc0ac;
    --as-color-warning: #d8bb66;
  }
}

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

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

body {
  margin: 0;
  background: var(--as-surface-primary);
  color: var(--as-text-primary);
  font-family: var(--as-font-sans);
  font-size: var(--as-type-body);
  line-height: var(--as-leading-body);
  -webkit-font-smoothing: antialiased;
}

/* ---------------------------------------------------------------- shell ---- */

.shell {
  width: 100%;
  max-width: var(--as-shell);
  margin: 0 auto;
  padding: 0 var(--as-space-6);
}

main section {
  padding: var(--as-space-12) 0;
}

main section + section {
  /* Sections are separated by space, not rules. */
  padding-top: 0;
}

section[id] {
  scroll-margin-top: 4.25rem;
}

/* --------------------------------------------------------------- header ---- */

.masthead {
  position: sticky;
  top: 0;
  z-index: 10;
  background: var(--as-surface-primary);
  /* The one border that earns itself: it separates scrolling content. */
  border-bottom: 1px solid var(--as-border-subtle);
}

.masthead .shell {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--as-space-6);
  height: 3.75rem;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: var(--as-space-2);
  font-weight: var(--as-weight-heading);
  color: var(--as-text-primary);
  text-decoration: none;
  letter-spacing: -0.01em;
}

.brand svg {
  display: block;
}

.masthead nav {
  display: flex;
  align-items: center;
  gap: var(--as-space-5);
  font-size: var(--as-type-compact);
}

/* ----------------------------------------------------------- typography ---- */

h1,
h2,
h3 {
  font-weight: var(--as-weight-heading);
  letter-spacing: -0.02em;
  margin: 0;
}

h1 {
  font-size: var(--as-type-display);
  line-height: var(--as-leading-display);
  letter-spacing: -0.03em;
  max-width: 30ch;
}

h2 {
  font-size: var(--as-type-page-title);
  line-height: var(--as-leading-title);
  max-width: 24ch;
}

h3 {
  font-size: var(--as-type-section);
  line-height: var(--as-leading-section);
}

p {
  margin: var(--as-space-4) 0 0;
  max-width: var(--as-measure);
}

.lede {
  font-size: 1.125rem;
  color: var(--as-text-secondary);
  margin-top: var(--as-space-5);
}

.lede strong {
  color: var(--as-text-primary);
  font-weight: var(--as-weight-medium);
}

.eyebrow {
  font-size: var(--as-type-label);
  font-weight: var(--as-weight-medium);
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--as-text-secondary);
  margin: 0 0 var(--as-space-3);
}

a {
  color: var(--as-accent);
  text-underline-offset: 0.2em;
}

a:hover {
  text-decoration-thickness: 2px;
}

:focus-visible {
  outline: 2px solid var(--as-focus);
  outline-offset: 2px;
  border-radius: var(--as-radius-small);
}

code {
  font-family: var(--as-font-mono);
  font-size: 0.9em;
}

p code,
li code,
dd code,
td code {
  background: var(--as-surface-emphasis);
  padding: 0.1em 0.35em;
  border-radius: var(--as-radius-small);
}

/* ---------------------------------------------------------------- code ---- */

pre {
  margin: var(--as-space-5) 0 0;
  padding: var(--as-space-4) var(--as-space-5);
  background: var(--as-surface-secondary);
  border: 1px solid var(--as-border-subtle);
  border-radius: var(--as-radius);
  overflow-x: auto;
  font-family: var(--as-font-mono);
  font-size: 0.875rem;
  line-height: 1.65;
}

/* Weight and dimming only — no colour, so it survives greyscale. */
pre .c {
  color: var(--as-text-secondary);
}

pre .k {
  font-weight: var(--as-weight-heading);
}

/* --------------------------------------------------------------- layout ---- */

.split {
  display: grid;
  grid-template-columns: minmax(0, 33rem) minmax(0, 1fr);
  gap: var(--as-space-8);
  align-items: start;
  margin-top: var(--as-space-6);
}

.split > div > p:first-child {
  margin-top: 0;
}

.positions {
  display: grid;
  gap: var(--as-space-6);
  margin: var(--as-space-8) 0 0;
}

@media (min-width: 52rem) {
  .positions.three {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

.positions dt {
  font-weight: var(--as-weight-heading);
  letter-spacing: -0.01em;
}

.positions dd {
  margin: var(--as-space-2) 0 0;
  color: var(--as-text-secondary);
  max-width: var(--as-measure);
}

.actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--as-space-3);
  margin-top: var(--as-space-8);
}

.btn {
  display: inline-flex;
  align-items: center;
  padding: 0.6rem 1.1rem;
  border-radius: var(--as-radius-small);
  border: 1px solid var(--as-border-default);
  font-size: var(--as-type-compact);
  font-weight: var(--as-weight-medium);
  text-decoration: none;
  color: var(--as-text-primary);
}

.btn.primary {
  background: var(--as-accent);
  border-color: var(--as-accent);
  color: var(--as-text-on-accent);
}

/* --------------------------------------------------------------- tables ---- */

.scroller {
  margin: var(--as-space-6) 0 0;
  overflow-x: auto;
}

table {
  border-collapse: collapse;
  width: 100%;
  font-size: var(--as-type-compact);
}

caption {
  caption-side: bottom;
  margin-top: var(--as-space-3);
  color: var(--as-text-secondary);
  font-size: var(--as-type-label);
  text-align: left;
  max-width: var(--as-measure);
}

th,
td {
  /* Text left, per the source document; there are no numeric columns here. */
  text-align: left;
  padding: var(--as-space-3) var(--as-space-4) var(--as-space-3) 0;
  border-bottom: 1px solid var(--as-border-subtle);
  vertical-align: top;
  white-space: nowrap;
}

thead th {
  font-weight: var(--as-weight-medium);
  color: var(--as-text-secondary);
  font-size: var(--as-type-label);
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

tbody th {
  font-weight: var(--as-weight-medium);
}

td.none {
  color: var(--as-text-secondary);
}

/* ---------------------------------------------------------------- notes ---- */

.note {
  margin: var(--as-space-6) 0 0;
  padding-left: var(--as-space-4);
  border-left: 2px solid var(--as-border-default);
  color: var(--as-text-secondary);
  max-width: var(--as-measure);
}

.note p:first-child {
  margin-top: 0;
}

/* Colour is never the only cue: every warn note names its limit in words. */
.note.warn {
  border-left-color: var(--as-color-warning);
}

/* --------------------------------------------------------------- footer ---- */

footer {
  border-top: 1px solid var(--as-border-subtle);
  margin-top: var(--as-space-16);
  padding: var(--as-space-8) 0 var(--as-space-12);
  color: var(--as-text-secondary);
  font-size: var(--as-type-compact);
}

footer .closer {
  color: var(--as-text-primary);
  max-width: var(--as-measure);
  margin: 0 0 var(--as-space-6);
}

footer nav {
  display: flex;
  flex-wrap: wrap;
  gap: var(--as-space-5);
}

/* ------------------------------------------------------------ utilities ---- */

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip-path: inset(50%);
  white-space: nowrap;
}

.skip {
  position: absolute;
  left: var(--as-space-4);
  top: -3rem;
  background: var(--as-surface-secondary);
  border: 1px solid var(--as-border-default);
  border-radius: var(--as-radius-small);
  padding: var(--as-space-2) var(--as-space-4);
  z-index: 20;
}

.skip:focus {
  top: var(--as-space-2);
}

/* Docs-only: the table of contents and dense definition lists. */
.toc {
  margin: var(--as-space-6) 0 0;
  padding: 0;
  list-style: none;
  columns: 2;
  column-gap: var(--as-space-8);
  font-size: var(--as-type-compact);
}

.toc li {
  margin-bottom: var(--as-space-2);
  break-inside: avoid;
}

.terms dt {
  font-weight: var(--as-weight-heading);
  margin-top: var(--as-space-5);
}

.terms dd {
  margin: var(--as-space-1) 0 0;
  color: var(--as-text-secondary);
  max-width: var(--as-measure);
}

@media (max-width: 52rem) {
  .split {
    grid-template-columns: minmax(0, 1fr);
  }

  .toc {
    columns: 1;
  }

  h1 {
    max-width: none;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
}