:root {
  color-scheme: dark;
  --bg: #0d1015;
  --text: #eef3f5;
  --muted: #9fb0b9;
  --accent: #4fb3a3;
  --line: rgba(151, 164, 176, 0.24);
}

* {
  box-sizing: border-box;
}

html,
body {
  min-height: 100%;
  margin: 0;
}

body {
  background: var(--bg);
  color: var(--text);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  letter-spacing: 0;
  overflow-x: hidden;
}

#signal-map {
  position: fixed;
  inset: 0;
  width: 100%;
  height: 100%;
  background:
    linear-gradient(180deg, rgba(13, 16, 21, 0.72), rgba(13, 16, 21, 0.98)),
    #0d1015;
  z-index: 0;
}

.shell {
  position: relative;
  z-index: 1;
  width: min(720px, calc(100% - 40px));
  min-height: 100vh;
  margin: 0 auto;
  display: grid;
  place-items: center;
}

.intro {
  width: 100%;
}

.eyebrow {
  margin: 0 0 18px;
  color: var(--muted);
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
}

h1 {
  max-width: 620px;
  margin: 0;
  font-size: clamp(3.2rem, 10vw, 7.4rem);
  line-height: 0.92;
  letter-spacing: 0;
}

.primary {
  min-height: 46px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  margin-top: 34px;
  padding: 0 22px;
  border: 1px solid transparent;
  border-radius: 6px;
  background: var(--accent);
  color: #07110f;
  text-decoration: none;
  font-weight: 800;
  transition: transform 160ms ease, border-color 160ms ease;
}

.primary:hover {
  transform: translateY(-1px);
  border-color: rgba(255, 255, 255, 0.28);
}

@media (max-width: 620px) {
  .shell {
    width: min(100% - 28px, 520px);
  }
}