:root {
  --background: #0b0b0b;
  --surface: #151515;
  --surface-hover: #1d1d1d;
  --text: #f4f1ea;
  --muted: #aba79f;
  --line: #30302d;
  --red: #e63e32;
  --yellow: #f4c542;
  --green: #7be495;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-width: 320px;
  background:
    radial-gradient(circle at 80% 10%, rgba(230, 62, 50, 0.12), transparent 28rem),
    radial-gradient(circle at 15% 85%, rgba(244, 197, 66, 0.08), transparent 24rem),
    var(--background);
  color: var(--text);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont,
    "Segoe UI", sans-serif;
  transition: background 180ms ease, color 180ms ease;
}

body.signal-mode {
  --background: #f3f0e8;
  --surface: #ffffff;
  --surface-hover: #ece8df;
  --text: #101010;
  --muted: #5d5a55;
  --line: #d4d0c8;
}

.shell {
  width: min(1120px, calc(100% - 3rem));
  margin: 0 auto;
  padding: 1.5rem 0 2.5rem;
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.75rem 0 2.5rem;
}

.brand {
  color: var(--text);
  font-size: 1.05rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-decoration: none;
}

.brand span {
  color: var(--red);
}

.status {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  color: var(--muted);
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
  font-size: 0.76rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.status-dot {
  width: 0.55rem;
  height: 0.55rem;
  border-radius: 50%;
  background: var(--green);
  box-shadow: 0 0 0.8rem rgba(123, 228, 149, 0.8);
}

.hero {
  max-width: 760px;
  padding: 4rem 0 5rem;
}

.eyebrow,
.card-number {
  margin: 0 0 1rem;
  color: var(--yellow);
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

h1 {
  max-width: 740px;
  margin: 0;
  font-size: clamp(3.7rem, 9vw, 7.8rem);
  font-weight: 850;
  letter-spacing: -0.085em;
  line-height: 0.88;
}

h1 span {
  color: var(--red);
}

.intro {
  max-width: 610px;
  margin: 2rem 0 0;
  color: var(--muted);
  font-size: clamp(1rem, 2vw, 1.17rem);
  line-height: 1.75;
}

.actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.85rem;
  margin-top: 2rem;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 2.8rem;
  border: 1px solid var(--line);
  border-radius: 0.35rem;
  padding: 0.7rem 1rem;
  color: var(--text);
  cursor: pointer;
  font: inherit;
  font-size: 0.93rem;
  font-weight: 700;
  text-decoration: none;
  transition: transform 150ms ease, background 150ms ease, border-color 150ms ease;
}

.button:hover {
  transform: translateY(-2px);
}

.button-primary {
  border-color: var(--red);
  background: var(--red);
  color: #ffffff;
}

.button-primary:hover {
  background: #c92d23;
}

.button-secondary {
  background: transparent;
}

.button-secondary:hover {
  background: var(--surface-hover);
  border-color: var(--yellow);
}

.grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  border-top: 1px solid var(--line);
  border-left: 1px solid var(--line);
}

.card {
  min-height: 230px;
  padding: 1.5rem;
  border-right: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  background: color-mix(in srgb, var(--surface) 78%, transparent);
  transition: background 160ms ease;
}

.card:hover {
  background: var(--surface-hover);
}

.card h2 {
  margin: 2.8rem 0 0.75rem;
  font-size: 1.2rem;
  letter-spacing: -0.03em;
}

.card p:last-child {
  margin: 0;
  color: var(--muted);
  line-height: 1.65;
}

footer {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  padding-top: 1.4rem;
  color: var(--muted);
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
  font-size: 0.75rem;
}

footer p {
  margin: 0;
}

@media (max-width: 720px) {
  .shell {
    width: min(100% - 2rem, 1120px);
  }

  .hero {
    padding: 2.75rem 0 3.5rem;
  }

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

  .card {
    min-height: auto;
  }

  .card h2 {
    margin-top: 1.5rem;
  }

  footer {
    flex-direction: column;
  }
}