:root {
  color-scheme: dark;
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: #0d1117;
  color: #f3f7fa;
}

* {
  box-sizing: border-box;
}

body {
  min-height: 100dvh;
  margin: 0;
  background: radial-gradient(circle at 50% 45%, rgba(42, 102, 130, 0.18), transparent 32%), #0d1117;
  overflow: hidden;
}

#signal-map {
  position: fixed;
  inset: 0;
  width: 100%;
  height: 100%;
  opacity: 0.52;
  pointer-events: none;
}

.center {
  position: relative;
  z-index: 1;
  min-height: 100dvh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 26px;
  padding: 24px;
  text-align: center;
}

h1 {
  margin: 0;
  font-size: 28px;
  font-weight: 650;
  letter-spacing: 0;
}

.buttons {
  display: grid;
  grid-template-columns: repeat(2, minmax(130px, 170px));
  gap: 12px;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
  padding: 0 18px;
  border: 1px solid rgba(255, 255, 255, 0.14);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.05);
  color: #f3f7fa;
  text-decoration: none;
  font-size: 16px;
  font-weight: 600;
  transition: background 140ms ease, border-color 140ms ease, transform 140ms ease;
}

.button:hover {
  transform: translateY(-1px);
  border-color: rgba(255, 255, 255, 0.28);
  background: rgba(255, 255, 255, 0.09);
}

@media (max-width: 430px) {
  .buttons {
    grid-template-columns: 1fr;
    width: min(100vw - 48px, 260px);
  }
}