/*
 * One stylesheet for both pages. No framework and no build step: this site is two
 * static files beside a serverless function, and adding a toolchain to it would be
 * more machinery than the thing it describes.
 */

:root {
  color-scheme: dark light;

  --bg: #0b1220;
  --bg-raised: #111c2f;
  --bg-sunken: #070d18;
  --border: #1e2d45;
  --border-strong: #2b3f5e;

  --text: #e8eef7;
  --text-dim: #9fb0c7;
  --text-faint: #6b7f99;

  --accent: #2fd39b;
  --accent-strong: #14b07b;
  --accent-dim: #0d7a5f;
  --warn: #f0b429;

  --radius: 14px;
  --radius-sm: 8px;
  --measure: 68ch;
  --page: 1140px;

  --mono: ui-monospace, "SF Mono", "JetBrains Mono", "Cascadia Code", Menlo, Consolas, monospace;
  --sans: "Inter", ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}

@media (prefers-color-scheme: light) {
  :root:not([data-theme="dark"]) {
    --bg: #f7f9fc;
    --bg-raised: #ffffff;
    --bg-sunken: #eef2f8;
    --border: #dde5ef;
    --border-strong: #c3d0e0;

    --text: #101a29;
    --text-dim: #4a5b72;
    --text-faint: #7488a1;

    --accent: #0d7a5f;
    --accent-strong: #0a6650;
    --accent-dim: #0d7a5f;
  }
}

:root[data-theme="light"] {
  --bg: #f7f9fc;
  --bg-raised: #ffffff;
  --bg-sunken: #eef2f8;
  --border: #dde5ef;
  --border-strong: #c3d0e0;
  --text: #101a29;
  --text-dim: #4a5b72;
  --text-faint: #7488a1;
  --accent: #0d7a5f;
  --accent-strong: #0a6650;
  --accent-dim: #0d7a5f;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  * { animation: none !important; transition: none !important; }
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--sans);
  font-size: 17px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

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

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

h1, h2, h3 { line-height: 1.2; letter-spacing: -0.02em; margin: 0; }
p { margin: 0 0 1rem; }
p.lead { max-width: var(--measure); color: var(--text-dim); }

code, kbd {
  font-family: var(--mono);
  font-size: 0.88em;
  background: var(--bg-sunken);
  border: 1px solid var(--border);
  border-radius: 5px;
  padding: 0.1em 0.4em;
}

/* ---------------------------------------------------------------- top bar */

header.top {
  position: sticky;
  top: 0;
  z-index: 40;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}

.top .wrap {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  height: 62px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-weight: 650;
  letter-spacing: -0.02em;
  color: var(--text);
  font-size: 1.05rem;
}
.brand:hover { text-decoration: none; }
.brand .mark {
  width: 26px; height: 26px;
  display: grid; place-items: center;
  border-radius: 7px;
  background: linear-gradient(140deg, var(--accent), var(--accent-dim));
  color: #04120d;
  font-weight: 800;
  font-size: 0.85rem;
}

nav.top-nav {
  margin-left: auto;
  display: flex;
  align-items: center;
  gap: 1.25rem;
  font-size: 0.93rem;
}
nav.top-nav a { color: var(--text-dim); }
nav.top-nav a:hover { color: var(--text); text-decoration: none; }
nav.top-nav a.active { color: var(--accent); }

@media (max-width: 640px) {
  nav.top-nav { gap: 0.9rem; font-size: 0.86rem; }
  nav.top-nav .hide-sm { display: none; }
}

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

.hero { padding: 5rem 0 3.5rem; }
.hero .eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--accent);
  background: color-mix(in srgb, var(--accent) 12%, transparent);
  border: 1px solid color-mix(in srgb, var(--accent) 28%, transparent);
  border-radius: 999px;
  padding: 0.3rem 0.8rem;
  margin-bottom: 1.4rem;
}
.hero h1 {
  font-size: clamp(2.2rem, 6vw, 3.6rem);
  font-weight: 700;
  max-width: 18ch;
  margin-bottom: 1.1rem;
}
.hero h1 .hl {
  background: linear-gradient(100deg, var(--accent), var(--accent-dim));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.hero p.lead { font-size: 1.12rem; }

.cta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 1.8rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.7rem 1.25rem;
  border-radius: var(--radius-sm);
  font-weight: 600;
  font-size: 0.95rem;
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform 0.12s ease, background 0.12s ease, border-color 0.12s ease;
}
.btn:hover { text-decoration: none; transform: translateY(-1px); }
.btn-primary { background: var(--accent); color: #04120d; }
.btn-primary:hover { background: var(--accent-strong); }
.btn-ghost { border-color: var(--border-strong); color: var(--text); background: var(--bg-raised); }
.btn-ghost:hover { border-color: var(--accent); }

/* ---------------------------------------------------------------- numbers */

.stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: 1px;
  background: var(--border);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  margin: 3rem 0;
}
.stat { background: var(--bg-raised); padding: 1.4rem 1.25rem; }
.stat b {
  display: block;
  font-size: 1.85rem;
  font-weight: 700;
  letter-spacing: -0.03em;
  font-variant-numeric: tabular-nums;
  color: var(--text);
}
.stat span { font-size: 0.85rem; color: var(--text-faint); }

/* ---------------------------------------------------------------- sections */

section.band {
  padding: 4rem 0;
  border-top: 1px solid var(--border);
  /* The header is sticky, so an anchor jump must stop short of sliding under it. */
  scroll-margin-top: 62px;
}
section.band > .wrap > h2 {
  font-size: clamp(1.5rem, 3.4vw, 2.1rem);
  margin-bottom: 0.8rem;
}
.section-intro { max-width: var(--measure); color: var(--text-dim); margin-bottom: 2.4rem; }

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(270px, 1fr));
  gap: 1.1rem;
}

.card {
  background: var(--bg-raised);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
}
.card h3 { font-size: 1.05rem; margin-bottom: 0.5rem; }
.card p { color: var(--text-dim); font-size: 0.95rem; margin: 0; }
.card .icon {
  width: 34px; height: 34px;
  display: grid; place-items: center;
  border-radius: var(--radius-sm);
  background: color-mix(in srgb, var(--accent) 14%, transparent);
  color: var(--accent);
  margin-bottom: 0.9rem;
}
.card .icon svg { width: 18px; height: 18px; }

/* ---------------------------------------------------------------- problem list */

.contrast {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 1.1rem;
}
.panel {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.6rem;
  background: var(--bg-raised);
}
.panel.before { border-color: color-mix(in srgb, var(--warn) 32%, var(--border)); }
.panel.after { border-color: color-mix(in srgb, var(--accent) 34%, var(--border)); }
.panel h3 { font-size: 0.82rem; text-transform: uppercase; letter-spacing: 0.07em; margin-bottom: 1rem; }
.panel.before h3 { color: var(--warn); }
.panel.after h3 { color: var(--accent); }
.panel ul { margin: 0; padding-left: 1.1rem; color: var(--text-dim); font-size: 0.95rem; }
.panel li { margin-bottom: 0.6rem; }
.panel li:last-child { margin-bottom: 0; }

/* ---------------------------------------------------------------- shots */

figure.shot { margin: 0; }
figure.shot img {
  display: block;
  width: 100%;
  height: auto;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--bg-sunken);
}
figure.shot figcaption {
  margin-top: 0.6rem;
  font-size: 0.85rem;
  color: var(--text-faint);
}
.shot-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 1.5rem;
}
.shot-wide { grid-column: 1 / -1; }

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

pre {
  background: var(--bg-sunken);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 1rem 1.1rem;
  overflow-x: auto;
  font-family: var(--mono);
  font-size: 0.85rem;
  line-height: 1.6;
  margin: 0 0 1rem;
}
pre code { background: none; border: none; padding: 0; font-size: inherit; }
.tok-c { color: var(--text-faint); }
.tok-k { color: var(--accent); }
.tok-s { color: #8fb8f0; }

/* ---------------------------------------------------------------- note */

.note {
  border-left: 3px solid var(--accent);
  background: color-mix(in srgb, var(--accent) 7%, transparent);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  padding: 1rem 1.2rem;
  font-size: 0.93rem;
  color: var(--text-dim);
  max-width: var(--measure);
}
.note strong { color: var(--text); }
.note.caution { border-left-color: var(--warn); background: color-mix(in srgb, var(--warn) 8%, transparent); }

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

footer.site {
  border-top: 1px solid var(--border);
  padding: 2.5rem 0 3.5rem;
  color: var(--text-faint);
  font-size: 0.88rem;
}
footer.site .cols {
  display: flex;
  flex-wrap: wrap;
  gap: 2rem;
  justify-content: space-between;
  align-items: flex-start;
}
footer.site a { color: var(--text-dim); }
footer.site nav { display: flex; gap: 1.2rem; flex-wrap: wrap; }
footer.site .disclaimer { max-width: 56ch; margin-top: 1.5rem; line-height: 1.6; }

/* ---------------------------------------------------------------- theme toggle */

.theme-toggle {
  background: none;
  border: 1px solid var(--border-strong);
  color: var(--text-dim);
  border-radius: var(--radius-sm);
  width: 34px; height: 34px;
  display: grid; place-items: center;
  cursor: pointer;
  padding: 0;
}
.theme-toggle:hover { color: var(--accent); border-color: var(--accent); }
.theme-toggle svg { width: 16px; height: 16px; }