:root {
  color-scheme: light;
  --bg: #0f1419;
  --bg-soft: #1a2332;
  --text: #f4f7fb;
  --muted: #9fb0c3;
  --accent: #3dd68c;
  --accent-strong: #22b86c;
  --violet: #8b7cf6;
  --card: rgba(255, 255, 255, 0.06);
  --border: rgba(255, 255, 255, 0.12);
  --radius: 20px;
  --font: "SF Pro Text", ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: var(--font);
  color: var(--text);
  background:
    radial-gradient(circle at 12% 8%, rgba(61, 214, 140, 0.18), transparent 32rem),
    radial-gradient(circle at 88% 12%, rgba(139, 124, 246, 0.2), transparent 28rem),
    linear-gradient(180deg, #121a24 0%, var(--bg) 55%, #0b1016 100%);
  min-height: 100vh;
}

a {
  color: inherit;
}

.site-header,
.site-footer,
main > section {
  width: min(1040px, calc(100% - 32px));
  margin-inline: auto;
}

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

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  font-weight: 700;
  font-size: 1.1rem;
}

.brand img {
  width: 44px;
  height: 44px;
  border-radius: 12px;
}

.site-header nav {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  font-size: 0.95rem;
}

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

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

.hero {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 32px;
  padding: 28px 0 48px;
  align-items: center;
}

@media (max-width: 860px) {
  .hero {
    grid-template-columns: 1fr;
  }
}

.eyebrow {
  text-transform: uppercase;
  letter-spacing: 0.12em;
  font-size: 0.75rem;
  color: var(--accent);
  font-weight: 700;
  margin: 0 0 10px;
}

h1 {
  font-size: clamp(2rem, 4vw, 3.2rem);
  line-height: 1.05;
  margin: 0 0 14px;
}

.lede {
  color: var(--muted);
  font-size: 1.08rem;
  line-height: 1.55;
  max-width: 38rem;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 22px;
  align-items: center;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 18px;
  border-radius: 999px;
  text-decoration: none;
  font-weight: 600;
  border: 1px solid var(--border);
}

.button.primary {
  background: linear-gradient(135deg, var(--accent), var(--violet));
  border: none;
  color: #04120a;
}

.button.secondary {
  background: var(--card);
  color: var(--text);
}

.challenge-card {
  display: none;
  margin: 0 0 28px;
  padding: 22px;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  background: var(--card);
  backdrop-filter: blur(12px);
}

.challenge-card.is-visible {
  display: block;
}

.challenge-card h2 {
  margin: 0 0 8px;
  font-size: 1.35rem;
}

.challenge-card p {
  margin: 0 0 16px;
  color: var(--muted);
}

.challenge-meta {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 10px;
  margin-bottom: 16px;
}

.challenge-meta div {
  padding: 12px;
  border-radius: 14px;
  background: rgba(0, 0, 0, 0.22);
  border: 1px solid var(--border);
}

.challenge-meta dt {
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--muted);
}

.challenge-meta dd {
  margin: 4px 0 0;
  font-weight: 700;
}

.hero-art {
  position: relative;
  min-height: 320px;
  border-radius: 28px;
  border: 1px solid var(--border);
  background:
    linear-gradient(145deg, rgba(61, 214, 140, 0.12), rgba(139, 124, 246, 0.12)),
    var(--bg-soft);
  padding: 24px;
  display: grid;
  grid-template-columns: repeat(8, 1fr);
  gap: 6px;
  align-content: center;
}

.grid-cell {
  aspect-ratio: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.08);
  font-weight: 700;
  font-size: 0.95rem;
}

.grid-cell.found {
  background: rgba(61, 214, 140, 0.35);
  color: #eafff3;
}

.section {
  padding: 20px 0 44px;
}

.section h2 {
  margin: 0 0 10px;
}

.section p {
  color: var(--muted);
  max-width: 46rem;
  line-height: 1.55;
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 14px;
  margin-top: 20px;
}

.card {
  padding: 18px;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  background: var(--card);
}

.card h3 {
  margin: 0 0 8px;
}

.card p {
  margin: 0;
  font-size: 0.95rem;
}

.site-footer {
  padding: 28px 0 40px;
  color: var(--muted);
  font-size: 0.9rem;
  border-top: 1px solid var(--border);
  margin-top: 20px;
}

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