formal-ai 0.205.0

Formal symbolic AI implementation with OpenAI-compatible APIs
/*
 * formal-ai landing page (issue #479).
 *
 * The site root (/) is a lightweight chooser that points visitors at the three
 * destinations the project ships: the interactive web app (/app/), the
 * documentation (/docs/), and the desktop download page (/download/).
 *
 * Palette, typography and the segmented language/theme switchers are kept byte
 * compatible with download.css so the chrome is identical across /, /download/
 * and /docs/. Theme is driven by the `data-theme` attribute that the chat app,
 * download.js and landing.js all set on <html>, so a visitor's choice is shared
 * across every page via the same Links-Notation-backed preferences store.
 */

:root {
  color-scheme: light;
  --bg: #eef2f1;
  --surface: #fbfcfd;
  --surface-strong: #e6ece9;
  --text: #1e252b;
  --muted: #5d6965;
  --line: #d6dde1;
  --accent: #175f4f;
  --accent-strong: #0f4a3d;
  --on-accent: #ffffff;
  --warm: #c0492f;
  --shadow: 0 18px 44px rgba(29, 36, 34, 0.12);
  font-family:
    Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI",
    sans-serif;
}

:root[data-theme="dark"] {
  color-scheme: dark;
  --bg: #181a1b;
  --surface: #202322;
  --surface-strong: #2b302e;
  --text: #ece7df;
  --muted: #a7b1ab;
  --line: #343a3d;
  --accent: #2c8f71;
  --accent-strong: #4fc3a0;
  --on-accent: #ffffff;
  --warm: #f08b70;
  --shadow: 0 18px 44px rgba(0, 0, 0, 0.32);
}

/*
 * Before landing.js sets an explicit data-theme (and for the <noscript>
 * fallback), follow the OS preference so the first paint matches the chat app.
 */
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    color-scheme: dark;
    --bg: #181a1b;
    --surface: #202322;
    --surface-strong: #2b302e;
    --text: #ece7df;
    --muted: #a7b1ab;
    --line: #343a3d;
    --accent: #2c8f71;
    --accent-strong: #4fc3a0;
    --warm: #f08b70;
    --shadow: 0 18px 44px rgba(0, 0, 0, 0.32);
  }
}

* {
  box-sizing: border-box;
}

body {
  min-width: 320px;
  margin: 0;
  color: var(--text);
  background: var(--bg);
}

a {
  color: inherit;
}

button,
a {
  -webkit-tap-highlight-color: transparent;
}

.page-shell {
  display: block;
  width: min(1180px, calc(100% - 32px));
  margin: 0 auto;
}

/* --- Top bar: brand + language/theme switchers ---------------------------- */

.landing-topbar {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  align-items: center;
  justify-content: space-between;
  padding: 20px 0 8px;
}

.brand {
  display: inline-flex;
  gap: 10px;
  align-items: center;
  font-size: 1.05rem;
  font-weight: 850;
  text-decoration: none;
}

.brand-mark {
  color: var(--accent);
  font-size: 1.1rem;
}

.topbar-controls {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  align-items: center;
}

.locale-switch,
.theme-switch {
  display: inline-flex;
  width: fit-content;
  padding: 4px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
}

.locale-switch button,
.theme-switch button {
  min-width: 44px;
  border: 0;
  border-radius: 6px;
  padding: 9px 12px;
  color: var(--muted);
  background: transparent;
  font: inherit;
  font-weight: 700;
  cursor: pointer;
}

.locale-switch button.active,
.theme-switch button.active {
  color: var(--surface);
  background: var(--text);
}

.locale-switch button:focus-visible,
.theme-switch button:focus-visible,
.nav-card:focus-visible,
.source-cta:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

/* --- Hero ------------------------------------------------------------------ */

.hero {
  display: grid;
  gap: 18px;
  padding: 48px 0 36px;
  max-width: 46rem;
}

.eyebrow {
  margin: 0;
  color: var(--accent-strong);
  font-size: 0.82rem;
  font-weight: 800;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

h1,
h2,
h3,
p {
  margin: 0;
}

h1 {
  font-size: 3.4rem;
  line-height: 1;
}

.summary {
  max-width: 38rem;
  color: var(--muted);
  font-size: 1.18rem;
  line-height: 1.55;
}

/* The big "Source on GitHub" call-to-action (issue #479: the maintainer asked
   that the source code on the landing be a big button, not a small footer
   link). It mirrors the /download page's .primary-download button -- accent
   fill, generous padding, a small action eyebrow above a strong label -- with a
   monospace code glyph so it reads unmistakably as "view the source code". */
.source-cta {
  display: inline-flex;
  align-items: center;
  gap: 16px;
  justify-self: start;
  min-height: 64px;
  margin-top: 4px;
  border-radius: 10px;
  padding: 14px 24px;
  color: var(--on-accent);
  background: var(--accent);
  text-decoration: none;
  box-shadow: var(--shadow);
  transition:
    background 0.15s ease,
    transform 0.1s ease;
}

.source-cta:hover {
  background: var(--accent-strong);
}

.source-cta:active {
  transform: translateY(1px);
}

.source-cta-icon {
  font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
  font-size: 1.5rem;
  font-weight: 800;
  line-height: 1;
}

.source-cta-text {
  display: grid;
  gap: 3px;
}

.source-cta-eyebrow {
  font-size: 0.8rem;
  font-weight: 750;
  letter-spacing: 0.03em;
  text-transform: uppercase;
  opacity: 0.85;
}

.source-cta-label {
  font-size: 1.3rem;
  font-weight: 800;
  line-height: 1.1;
}

/* --- Navigation cards (the chooser) --------------------------------------- */

.nav-cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 18px;
  padding: 8px 0 56px;
}

.nav-card {
  display: grid;
  grid-template-rows: auto auto 1fr auto;
  gap: 10px;
  min-height: 200px;
  padding: 24px;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: var(--surface);
  box-shadow: var(--shadow);
  text-decoration: none;
  transition:
    transform 0.16s ease,
    border-color 0.16s ease;
}

.nav-card:hover {
  transform: translateY(-3px);
  border-color: var(--accent);
}

.nav-card-icon {
  font-size: 1.9rem;
  line-height: 1;
}

.nav-card-title {
  font-size: 1.35rem;
  font-weight: 800;
}

.nav-card-desc {
  align-self: start;
  color: var(--muted);
  font-size: 1rem;
  line-height: 1.5;
}

.nav-card-action {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: var(--accent-strong);
  font-weight: 750;
}

.nav-card-action::after {
  content: "";
}

/* --- Footer --------------------------------------------------------------- */

.landing-footer {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 18px;
  align-items: center;
  padding: 8px 0 48px;
  color: var(--muted);
  font-size: 0.92rem;
}

@media (max-width: 640px) {
  h1 {
    font-size: 2.6rem;
  }

  .source-cta {
    width: 100%;
  }
}