/* Kryon — website styles.
   Plain CSS, no build step, no framework. Tokens first, then layout, then components. */

/* ---------- tokens ---------- */

:root {
  color-scheme: light dark;

  --bg: #ffffff;
  --bg-subtle: #f6f7f9;
  --bg-code: #f3f4f6;
  --bg-raised: #ffffff;

  --fg: #10131a;
  --fg-muted: #575e6b;
  --fg-faint: #868d99;

  --border: #e2e5ea;
  --border-strong: #cdd2da;

  --accent: #1f6feb;
  --accent-fg: #ffffff;
  --accent-subtle: #e8f0fe;

  --ok: #1a7f37;
  --warn: #9a6700;
  --off: #6e7681;

  --radius: 10px;
  --radius-sm: 6px;
  --maxw: 1080px;

  --mono: ui-monospace, "SF Mono", "JetBrains Mono", "Cascadia Mono", Menlo, Consolas,
    "Liberation Mono", monospace;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Inter, Roboto, "Helvetica Neue",
    Arial, sans-serif;

  --shadow: 0 1px 2px rgba(16, 19, 26, 0.05), 0 4px 16px rgba(16, 19, 26, 0.05);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #0d1117;
    --bg-subtle: #12181f;
    --bg-code: #161b22;
    --bg-raised: #12181f;

    --fg: #e6edf3;
    --fg-muted: #9aa5b1;
    --fg-faint: #6e7681;

    --border: #232b35;
    --border-strong: #333d49;

    --accent: #58a6ff;
    --accent-fg: #06121f;
    --accent-subtle: #16273d;

    --ok: #3fb950;
    --warn: #d29922;

    --shadow: 0 1px 2px rgba(0, 0, 0, 0.3), 0 4px 16px rgba(0, 0, 0, 0.25);
  }
}

/* Explicit choice wins in both directions. Declared separately so it applies even when
   the browser reports a light preference. */
:root[data-theme="dark"] {
  --bg: #0d1117;
  --bg-subtle: #12181f;
  --bg-code: #161b22;
  --bg-raised: #12181f;
  --fg: #e6edf3;
  --fg-muted: #9aa5b1;
  --fg-faint: #6e7681;
  --border: #232b35;
  --border-strong: #333d49;
  --accent: #58a6ff;
  --accent-fg: #06121f;
  --accent-subtle: #16273d;
  --ok: #3fb950;
  --warn: #d29922;
  --shadow: 0 1px 2px rgba(0, 0, 0, 0.3), 0 4px 16px rgba(0, 0, 0, 0.25);
}

/* ---------- base ---------- */

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: 5rem;
}

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

body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

h1,
h2,
h3,
h4 {
  line-height: 1.2;
  letter-spacing: -0.02em;
  margin: 0 0 0.5em;
  font-weight: 640;
}

h1 {
  font-size: clamp(2.25rem, 6vw, 3.75rem);
  letter-spacing: -0.035em;
}
h2 {
  font-size: clamp(1.5rem, 3.5vw, 2rem);
}
h3 {
  font-size: 1.125rem;
}

p {
  margin: 0 0 1rem;
}

a {
  color: var(--accent);
  text-decoration-thickness: 1px;
  text-underline-offset: 2px;
}

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

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
  border-radius: 3px;
}

code,
kbd,
pre {
  font-family: var(--mono);
  font-size: 0.875em;
}

:not(pre) > code {
  background: var(--bg-code);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 0.1em 0.35em;
  white-space: nowrap;
}

hr {
  border: 0;
  border-top: 1px solid var(--border);
  margin: 4rem 0;
}

.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  background: var(--accent);
  color: var(--accent-fg);
  padding: 0.75rem 1.25rem;
  z-index: 100;
  border-radius: 0 0 var(--radius) 0;
}

.skip-link:focus {
  left: 0;
}

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

.wrap {
  max-width: var(--maxw);
  margin-inline: auto;
  padding-inline: 1.25rem;
}

section {
  padding-block: clamp(3rem, 8vw, 5.5rem);
  border-top: 1px solid var(--border);
}

section > .wrap > h2 {
  margin-bottom: 0.25rem;
}

.section-lede {
  color: var(--fg-muted);
  max-width: 62ch;
  margin-bottom: 2.5rem;
  font-size: 1.05rem;
}

.grid {
  display: grid;
  gap: 1.25rem;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
}

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

header.site {
  position: sticky;
  top: 0;
  z-index: 50;
  background: var(--bg);
  border-bottom: 1px solid var(--border);
}

header.site .wrap {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  height: 60px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-weight: 680;
  font-size: 1.05rem;
  letter-spacing: -0.02em;
  color: var(--fg);
  text-decoration: none;
}

.brand svg {
  width: 24px;
  height: 24px;
  flex: none;
}

nav.site {
  margin-left: auto;
  display: flex;
  align-items: center;
  gap: 0.35rem;
}

nav.site a {
  color: var(--fg-muted);
  text-decoration: none;
  padding: 0.4rem 0.7rem;
  border-radius: var(--radius-sm);
  font-size: 0.925rem;
}

nav.site a:hover {
  color: var(--fg);
  background: var(--bg-subtle);
}

@media (max-width: 760px) {
  nav.site a.hide-sm {
    display: none;
  }
}

/* At phone widths the brand plus the remaining links exceed the viewport, which forces a
   horizontal scrollbar on the whole page. Let the header wrap rather than dropping links --
   a Docs link nobody can reach is worse than a header two rows tall. */
@media (max-width: 560px) {
  header.site .wrap {
    height: auto;
    min-height: 56px;
    padding-block: 0.5rem;
    flex-wrap: wrap;
    gap: 0.5rem;
  }

  nav.site {
    gap: 0.1rem;
  }

  nav.site a {
    padding: 0.35rem 0.45rem;
    font-size: 0.85rem;
  }
}

.theme-toggle {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--fg-muted);
  border-radius: var(--radius-sm);
  width: 34px;
  height: 34px;
  display: grid;
  place-items: center;
  cursor: pointer;
  flex: none;
}

.theme-toggle:hover {
  color: var(--fg);
  border-color: var(--border-strong);
}

/* ---------- hero ---------- */

.hero {
  border-top: 0;
  padding-block: clamp(3.5rem, 10vw, 6.5rem) clamp(3rem, 7vw, 4.5rem);
  background:
    radial-gradient(60rem 30rem at 50% -10rem, var(--accent-subtle), transparent 70%);
}

.hero h1 {
  max-width: 18ch;
}

.hero .tagline {
  font-size: clamp(1.15rem, 2.5vw, 1.4rem);
  color: var(--fg-muted);
  max-width: 56ch;
  margin-bottom: 1.5rem;
}

.status-pill {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.8rem;
  font-family: var(--mono);
  color: var(--warn);
  border: 1px solid color-mix(in srgb, var(--warn) 35%, var(--border));
  background: color-mix(in srgb, var(--warn) 8%, transparent);
  border-radius: 999px;
  padding: 0.25rem 0.8rem;
  margin-bottom: 1.5rem;
}

.cta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-bottom: 2.5rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.6rem 1.15rem;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-strong);
  text-decoration: none;
  font-weight: 550;
  font-size: 0.95rem;
  color: var(--fg);
  background: var(--bg-raised);
}

.btn:hover {
  border-color: var(--fg-faint);
}

.btn.primary {
  background: var(--accent);
  border-color: var(--accent);
  color: var(--accent-fg);
}

.btn.primary:hover {
  filter: brightness(1.08);
}

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

.code {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--bg-code);
  overflow: hidden;
  box-shadow: var(--shadow);
}

.code-head {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem 0.75rem;
  border-bottom: 1px solid var(--border);
  background: var(--bg-subtle);
}

.code-head .dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--border-strong);
}

.code-head .name {
  font-family: var(--mono);
  font-size: 0.75rem;
  color: var(--fg-faint);
  margin-left: 0.4rem;
}

.copy {
  margin-left: auto;
  background: transparent;
  border: 1px solid var(--border);
  color: var(--fg-muted);
  border-radius: var(--radius-sm);
  padding: 0.2rem 0.6rem;
  font-size: 0.75rem;
  cursor: pointer;
  font-family: var(--sans);
}

.copy:hover {
  color: var(--fg);
  border-color: var(--border-strong);
}

.code pre {
  margin: 0;
  padding: 1rem 1.1rem;
  overflow-x: auto;
  line-height: 1.7;
}

.code pre code {
  white-space: pre;
}

/* Minimal, hand-applied highlighting. No highlighter library: the pages have a dozen
   snippets, and a syntax highlighter would be more code than the entire site. */
.t-kw { color: #cf222e; }
.t-str { color: #0a3069; }
.t-com { color: var(--fg-faint); font-style: italic; }
.t-fn { color: #6639ba; }
.t-num { color: #0550ae; }

:root[data-theme="dark"] .t-kw { color: #ff7b72; }
:root[data-theme="dark"] .t-str { color: #a5d6ff; }
:root[data-theme="dark"] .t-fn { color: #d2a8ff; }
:root[data-theme="dark"] .t-num { color: #79c0ff; }

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .t-kw { color: #ff7b72; }
  :root:not([data-theme="light"]) .t-str { color: #a5d6ff; }
  :root:not([data-theme="light"]) .t-fn { color: #d2a8ff; }
  :root:not([data-theme="light"]) .t-num { color: #79c0ff; }
}

/* ---------- cards ---------- */

.card {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.35rem;
  background: var(--bg-raised);
}

.card h3 {
  margin-bottom: 0.4rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.card p {
  color: var(--fg-muted);
  margin: 0;
  font-size: 0.95rem;
}

.card p + p {
  margin-top: 0.75rem;
}

a.card {
  text-decoration: none;
  color: inherit;
  display: block;
  transition: border-color 0.15s ease;
}

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

a.card h3 {
  color: var(--accent);
}

/* ---------- badges ---------- */

.badge {
  font-family: var(--mono);
  font-size: 0.68rem;
  letter-spacing: 0.02em;
  text-transform: uppercase;
  border-radius: 999px;
  padding: 0.15rem 0.55rem;
  border: 1px solid currentColor;
  white-space: nowrap;
  font-weight: 600;
}

.badge.done {
  color: var(--ok);
}
.badge.spec {
  color: var(--accent);
}
.badge.todo {
  color: var(--off);
}
.badge.warn {
  color: var(--warn);
}

/* ---------- architecture ---------- */

.layers {
  display: flex;
  flex-direction: column-reverse;
  gap: 0.5rem;
  font-family: var(--mono);
}

.layer {
  display: flex;
  align-items: center;
  gap: 1rem;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 0.9rem 1.1rem;
  background: var(--bg-raised);
  flex-wrap: wrap;
}

.layer.implemented {
  border-color: var(--ok);
  background: color-mix(in srgb, var(--ok) 7%, var(--bg-raised));
}

.layer .n {
  color: var(--fg-faint);
  font-size: 0.85rem;
  flex: none;
  width: 1.5rem;
}

.layer .title {
  font-weight: 600;
  font-size: 0.95rem;
  flex: none;
  min-width: 11rem;
}

.layer .desc {
  color: var(--fg-muted);
  font-size: 0.85rem;
  font-family: var(--sans);
  flex: 1 1 16rem;
}

.layer .badge {
  margin-left: auto;
}

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

.table-scroll {
  overflow-x: auto;
  border: 1px solid var(--border);
  border-radius: var(--radius);
}

table {
  border-collapse: collapse;
  width: 100%;
  font-size: 0.9rem;
  min-width: 34rem;
}

th,
td {
  text-align: left;
  padding: 0.7rem 1rem;
  border-bottom: 1px solid var(--border);
}

th {
  background: var(--bg-subtle);
  font-weight: 620;
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.03em;
  color: var(--fg-muted);
}

tbody tr:last-child td {
  border-bottom: 0;
}

td code {
  white-space: nowrap;
}

/* ---------- callout ---------- */

.callout {
  border: 1px solid color-mix(in srgb, var(--warn) 40%, var(--border));
  background: color-mix(in srgb, var(--warn) 7%, transparent);
  border-left-width: 3px;
  border-radius: var(--radius-sm);
  padding: 1.1rem 1.35rem;
}

.callout h3 {
  margin-bottom: 0.4rem;
  color: var(--warn);
}

.callout p:last-child {
  margin-bottom: 0;
}

.callout ol {
  margin: 0.75rem 0 0;
  padding-left: 1.25rem;
  color: var(--fg-muted);
}

.callout li {
  margin-bottom: 0.35rem;
}

/* ---------- tabs ---------- */

.tabs {
  display: flex;
  gap: 0.25rem;
  border-bottom: 1px solid var(--border);
  margin-bottom: 1.25rem;
  overflow-x: auto;
}

.tab {
  background: transparent;
  border: 0;
  border-bottom: 2px solid transparent;
  color: var(--fg-muted);
  padding: 0.55rem 0.9rem;
  cursor: pointer;
  font-size: 0.925rem;
  font-family: inherit;
  white-space: nowrap;
}

.tab[aria-selected="true"] {
  color: var(--fg);
  border-bottom-color: var(--accent);
  font-weight: 560;
}

.tab:hover {
  color: var(--fg);
}

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

footer.site {
  border-top: 1px solid var(--border);
  background: var(--bg-subtle);
  padding-block: 3rem 2rem;
  font-size: 0.9rem;
}

footer.site .cols {
  display: grid;
  gap: 2rem;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  margin-bottom: 2.5rem;
}

footer.site h4 {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--fg-faint);
  margin-bottom: 0.75rem;
}

footer.site ul {
  list-style: none;
  margin: 0;
  padding: 0;
}

footer.site li {
  margin-bottom: 0.4rem;
}

footer.site a {
  color: var(--fg-muted);
  text-decoration: none;
}

footer.site a:hover {
  color: var(--accent);
  text-decoration: underline;
}

footer.site .fine {
  border-top: 1px solid var(--border);
  padding-top: 1.5rem;
  color: var(--fg-faint);
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 1.5rem;
  justify-content: space-between;
}

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

.muted {
  color: var(--fg-muted);
}

.mono {
  font-family: var(--mono);
}

.center {
  text-align: center;
}

.stack-lg > * + * {
  margin-top: 2rem;
}

.two-col {
  display: grid;
  gap: 2rem;
  grid-template-columns: 1fr;
}

@media (min-width: 880px) {
  .two-col {
    grid-template-columns: 1fr 1fr;
    align-items: start;
  }
}

[hidden] {
  display: none !important;
}