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

:root {
  --text: #111111;
  --text-muted: #666666;
  --text-faint: #999999;
  --border: #e0e0e0;
  --bg: #ffffff;
  --max-width: 720px;

  --tag-content-bg: #dbeafe;
  --tag-content-text: #1d4ed8;
  --tag-signal-bg: #dcfce7;
  --tag-signal-text: #15803d;
  --tag-research-bg: #ede9fe;
  --tag-research-text: #6d28d9;
  --tag-pipeline-bg: #fef3c7;
  --tag-pipeline-text: #b45309;
  --tag-ops-bg: #f3f4f6;
  --tag-ops-text: #4b5563;
  --tag-agentic-bg: #ffe4d6;
  --tag-agentic-text: #c2410c;

  --status-building-bg: #fef3c7;
  --status-building-text: #b45309;
  --status-live-bg: #dcfce7;
  --status-live-text: #15803d;
  --status-coming-bg: #f3f4f6;
  --status-coming-text: #9ca3af;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

/* ── Layout ── */

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

section {
  padding: 80px 0;
}

section + section {
  border-top: 1px solid var(--border);
}

/* ── Nav ── */

nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: transparent;
  transition: background 0.2s ease, border-bottom 0.2s ease;
}

nav.scrolled {
  background: var(--bg);
  border-bottom: 1px solid var(--border);
}

.nav-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
  height: 56px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  font-size: 0.9375rem;
  font-weight: 500;
  color: var(--text);
  text-decoration: none;
  letter-spacing: -0.01em;
}

.nav-links {
  display: flex;
  gap: 28px;
  list-style: none;
}

.nav-links a {
  font-size: 0.875rem;
  color: var(--text-muted);
  text-decoration: none;
  transition: color 0.15s;
}

.nav-links a:hover {
  color: var(--text);
}

/* ── Hero ── */

#hero {
  padding-top: 96px;
  padding-bottom: 96px;
  border-top: none;
}

.hero-tag {
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-faint);
  margin-bottom: 20px;
}

.hero-headline {
  font-size: clamp(2.25rem, 6vw, 3rem);
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.1;
  margin-bottom: 20px;
  color: var(--text);
}

.hero-sub {
  font-size: 1.0625rem;
  color: var(--text-muted);
  max-width: 540px;
  line-height: 1.65;
  margin-bottom: 36px;
}

.hero-actions {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

.btn {
  display: inline-block;
  padding: 10px 20px;
  font-size: 0.9375rem;
  font-weight: 500;
  text-decoration: none;
  border: 1.5px solid var(--text);
  color: var(--text);
  background: transparent;
  cursor: pointer;
  transition: background 0.15s, color 0.15s;
  letter-spacing: -0.01em;
}

.btn:hover {
  background: var(--text);
  color: var(--bg);
}

.btn-primary {
  background: var(--text);
  color: var(--bg);
}

.btn-primary:hover {
  background: #333;
  border-color: #333;
}

/* ── Section labels ── */

.section-label {
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-faint);
  margin-bottom: 40px;
}

/* ── Experiments Grid ── */

.experiments-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
  background: var(--border);
  border: 1px solid var(--border);
}

.experiment-card {
  background: var(--bg);
  padding: 24px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.experiment-id {
  font-size: 0.75rem;
  color: var(--text-faint);
  font-variant-numeric: tabular-nums;
  font-weight: 500;
  letter-spacing: 0.05em;
}

.experiment-title {
  font-size: 0.9375rem;
  font-weight: 500;
  color: var(--text);
  line-height: 1.4;
  flex: 1;
}

.experiment-meta {
  display: flex;
  gap: 8px;
  align-items: center;
  flex-wrap: wrap;
}

.tag {
  font-size: 0.6875rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  padding: 3px 8px;
  border-radius: 999px;
}

.tag-content  { background: var(--tag-content-bg);  color: var(--tag-content-text); }
.tag-signal   { background: var(--tag-signal-bg);   color: var(--tag-signal-text); }
.tag-research { background: var(--tag-research-bg); color: var(--tag-research-text); }
.tag-pipeline { background: var(--tag-pipeline-bg); color: var(--tag-pipeline-text); }
.tag-ops      { background: var(--tag-ops-bg);      color: var(--tag-ops-text); }
.tag-agentic  { background: var(--tag-agentic-bg);  color: var(--tag-agentic-text); }

.status {
  font-size: 0.6875rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  padding: 3px 8px;
  border-radius: 999px;
}

.status-building { background: var(--status-building-bg); color: var(--status-building-text); }
.status-live     { background: var(--status-live-bg);     color: var(--status-live-text); }
.status-coming   { background: var(--status-coming-bg);   color: var(--status-coming-text); }

/* ── Built section ── */

.built-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1px;
  background: var(--border);
  border: 1px solid var(--border);
}

.built-card {
  background: var(--bg);
  padding: 28px;
}

.built-card.accent {
  border: 2px solid var(--text);
  margin: -1px;
}

.built-card-title {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 8px;
  letter-spacing: -0.01em;
}

.built-card-desc {
  font-size: 0.9375rem;
  color: var(--text-muted);
  line-height: 1.55;
}

.built-card.wide {
  grid-column: span 2;
}

/* ── Speaking ── */

.speaking-card {
  border: 1px solid var(--border);
  padding: 28px;
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 16px;
  align-items: start;
}

.speaking-event {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 4px;
  letter-spacing: -0.01em;
}

.speaking-date {
  font-size: 0.875rem;
  color: var(--text-faint);
  margin-bottom: 12px;
}

.speaking-talk {
  font-size: 0.9375rem;
  font-weight: 500;
  color: var(--text);
  margin-bottom: 6px;
}

.speaking-desc {
  font-size: 0.9375rem;
  color: var(--text-muted);
  line-height: 1.55;
}

.speaking-badge {
  font-size: 0.6875rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  border: 1.5px solid var(--text);
  padding: 4px 10px;
  white-space: nowrap;
}

/* ── Work with me ── */

.cohort-card {
  border: 1px solid var(--border);
  padding: 32px;
}

.cohort-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: 12px;
  gap: 16px;
}

.cohort-title {
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--text);
  letter-spacing: -0.02em;
}

.cohort-date {
  font-size: 0.875rem;
  color: var(--text-faint);
  white-space: nowrap;
  padding-top: 2px;
}

.cohort-desc {
  font-size: 0.9375rem;
  color: var(--text-muted);
  line-height: 1.6;
  margin-bottom: 8px;
}

.cohort-spots {
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--text-muted);
  letter-spacing: 0.02em;
  margin-bottom: 24px;
}

.register-form {
  display: flex;
  gap: 0;
  max-width: 440px;
}

.register-form input[type="email"] {
  flex: 1;
  padding: 10px 14px;
  font-size: 0.9375rem;
  border: 1.5px solid var(--border);
  border-right: none;
  outline: none;
  font-family: inherit;
  color: var(--text);
  background: var(--bg);
  transition: border-color 0.15s;
}

.register-form input[type="email"]:focus {
  border-color: var(--text);
}

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

.register-form button {
  padding: 10px 18px;
  font-size: 0.9375rem;
  font-weight: 500;
  font-family: inherit;
  background: var(--text);
  color: var(--bg);
  border: 1.5px solid var(--text);
  cursor: pointer;
  transition: background 0.15s;
  white-space: nowrap;
}

.register-form button:hover {
  background: #333;
  border-color: #333;
}

.register-thanks {
  display: none;
  font-size: 0.9375rem;
  color: var(--text-muted);
  padding: 10px 0;
}

.register-thanks.visible {
  display: block;
}

/* ── About ── */

.about-text {
  font-size: 1.0625rem;
  color: var(--text-muted);
  line-height: 1.7;
  max-width: 600px;
}

/* ── Footer ── */

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

.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
}

.footer-brand {
  font-size: 0.9375rem;
  font-weight: 500;
  color: var(--text);
  text-decoration: none;
}

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

.footer-links a {
  font-size: 0.875rem;
  color: var(--text-muted);
  text-decoration: none;
  transition: color 0.15s;
}

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

/* ── Responsive ── */

@media (max-width: 600px) {
  section {
    padding: 56px 0;
  }

  #hero {
    padding-top: 64px;
    padding-bottom: 64px;
  }

  .nav-links {
    gap: 16px;
  }

  .nav-links a {
    font-size: 0.8125rem;
  }

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

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

  .built-card.wide {
    grid-column: span 1;
  }

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

  .cohort-header {
    flex-direction: column;
    gap: 4px;
  }

  .register-form {
    flex-direction: column;
    max-width: 100%;
  }

  .register-form input[type="email"] {
    border-right: 1.5px solid var(--border);
    border-bottom: none;
  }

  .register-form input[type="email"]:focus {
    border-color: var(--text);
  }

  .footer-inner {
    flex-direction: column;
    align-items: flex-start;
    gap: 12px;
  }
}