@import url('https://fonts.googleapis.com/css2?family=JetBrains+Mono:wght@400;500&family=Inter:wght@400;500&display=swap');

:root {
  --bg: #0a0a0a;
  --bg-subtle: #111111;
  --border: #222222;
  --text: #e5e5e5;
  --text-muted: #888888;
  --white: #ffffff;
  --accent: #e5e5e5;

  --font-mono: 'JetBrains Mono', ui-monospace, 'Cascadia Code', 'Source Code Pro', Menlo, monospace;
  --font-sans: 'Inter', ui-sans-serif, system-ui, -apple-system, sans-serif;

  --max-width: 760px;
  --section-gap: 80px;
  --section-gap-sm: 48px;
}

*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  background-color: var(--bg);
  color: var(--text);
  font-family: var(--font-sans);
  font-size: 1rem;
  line-height: 1.65;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

/* ─── Typography ─────────────────────────────────── */

h1, h2, h3 {
  font-family: var(--font-mono);
  color: var(--white);
  font-weight: 500;
  letter-spacing: -0.02em;
  line-height: 1.2;
}

p {
  color: var(--text);
  line-height: 1.7;
}

a {
  color: var(--text);
  text-decoration: underline;
  text-underline-offset: 3px;
}

a:hover {
  color: var(--white);
}

/* ─── Header ─────────────────────────────────────── */

header {
  padding: 40px 0 80px;
}

.brand {
  font-family: var(--font-mono);
  font-size: 1rem;
  font-weight: 500;
  color: var(--white);
  letter-spacing: 0.08em;
  text-decoration: none;
}

.brand:hover {
  color: var(--white);
}

/* ─── Hero ───────────────────────────────────────── */

.hero {
  padding-bottom: var(--section-gap);
}

.hero h1 {
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  margin-bottom: 20px;
  max-width: 600px;
}

.hero-sub {
  color: var(--text-muted);
  font-size: 1.0625rem;
  max-width: 480px;
  margin-bottom: 36px;
}

.hero-sub br {
  display: block;
  content: '';
  margin-top: 4px;
}

/* ─── Waitlist Form ──────────────────────────────── */

.waitlist-form {
  display: flex;
  gap: 8px;
  margin-bottom: 12px;
  max-width: 480px;
}

.waitlist-form input[type="email"] {
  flex: 1;
  background: var(--bg-subtle);
  border: 1px solid var(--border);
  color: var(--white);
  font-family: var(--font-sans);
  font-size: 0.9375rem;
  padding: 10px 14px;
  border-radius: 4px;
  outline: none;
  transition: border-color 0.15s;
  min-width: 0;
}

.waitlist-form input[type="email"]::placeholder {
  color: var(--text-muted);
}

.waitlist-form input[type="email"]:focus {
  border-color: #444;
}

.waitlist-form button {
  background: var(--white);
  color: var(--bg);
  border: none;
  font-family: var(--font-sans);
  font-size: 0.9375rem;
  font-weight: 500;
  padding: 10px 20px;
  border-radius: 4px;
  cursor: pointer;
  white-space: nowrap;
  transition: opacity 0.15s;
}

.waitlist-form button:hover {
  opacity: 0.88;
}

.waitlist-form button:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.form-note {
  font-size: 0.8125rem;
  color: var(--text-muted);
}

.form-confirmation {
  display: none;
  font-family: var(--font-mono);
  font-size: 0.9375rem;
  color: var(--white);
  padding: 12px 0;
}

.form-error {
  display: none;
  font-size: 0.8125rem;
  color: #f87171;
  margin-top: 8px;
}

/* ─── Sections ───────────────────────────────────── */

section {
  padding-bottom: var(--section-gap);
}

.section-heading {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--text-muted);
  letter-spacing: 0.1em;
  text-transform: uppercase;
  margin-bottom: 28px;
}

/* ─── Problem ────────────────────────────────────── */

.problem-body p + p {
  margin-top: 20px;
}

/* ─── What Stratum Does ──────────────────────────── */

.columns {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0;
  border: 1px solid var(--border);
  border-radius: 4px;
  overflow: hidden;
}

.column {
  padding: 28px 32px;
}

.column + .column {
  border-left: 1px solid var(--border);
}

.column-label {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--text-muted);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  margin-bottom: 20px;
}

.column-items {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.column-item {
  font-size: 0.9375rem;
  line-height: 1.6;
  color: var(--text);
}

.column-item strong {
  display: block;
  color: var(--white);
  font-weight: 500;
  font-size: 0.875rem;
  margin-bottom: 3px;
}

/* ─── Architecture ───────────────────────────────── */

.arch-intro {
  margin-bottom: 28px;
}

.arch-stack {
  border: 1px solid var(--border);
  border-radius: 4px;
  overflow: hidden;
}

.arch-row {
  display: flex;
  align-items: baseline;
  gap: 16px;
  padding: 13px 20px;
  font-size: 0.9375rem;
}

.arch-row + .arch-row {
  border-top: 1px solid var(--border);
}

.arch-label {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  color: var(--white);
  white-space: nowrap;
  min-width: 120px;
}

.arch-desc {
  color: var(--text-muted);
  font-size: 0.875rem;
}

/* ─── Open Source ────────────────────────────────── */

.oss-body {
  margin-bottom: 20px;
}

.oss-link {
  font-family: var(--font-mono);
  font-size: 0.875rem;
  color: var(--text);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.oss-link:hover {
  color: var(--white);
}

/* ─── Footer ─────────────────────────────────────── */

footer {
  border-top: 1px solid var(--border);
  padding: 32px 0 48px;
}

.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  flex-wrap: wrap;
}

.footer-left {
  font-size: 0.875rem;
  color: var(--text-muted);
}

.footer-left a {
  color: var(--text-muted);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.footer-left a:hover {
  color: var(--white);
}

.footer-links {
  display: flex;
  align-items: center;
  gap: 20px;
  list-style: none;
}

.footer-links a {
  font-size: 0.875rem;
  color: var(--text-muted);
  text-decoration: none;
}

.footer-links a:hover {
  color: var(--white);
}

.footer-cf {
  font-size: 0.8125rem;
  color: var(--text-muted);
  width: 100%;
}

/* ─── Divider ────────────────────────────────────── */

.divider {
  border: none;
  border-top: 1px solid var(--border);
  margin-bottom: var(--section-gap);
}

/* ─── Responsive ─────────────────────────────────── */

@media (max-width: 600px) {
  :root {
    --section-gap: 56px;
  }

  header {
    padding: 28px 0 56px;
  }

  .waitlist-form {
    flex-direction: column;
  }

  .waitlist-form button {
    width: 100%;
    padding: 12px 20px;
  }

  .columns {
    grid-template-columns: 1fr;
  }

  .column + .column {
    border-left: none;
    border-top: 1px solid var(--border);
  }

  .column {
    padding: 24px 20px;
  }

  .footer-inner {
    flex-direction: column;
    align-items: flex-start;
    gap: 16px;
  }
}