:root {
  --bg: #0b0f14;
  --fg: #e8eef6;
  --muted: #9fb0c3;
  --card: #121821;
  --accent: #4ea1ff;
  --accent-strong: #2b8cff;
  --ring: rgba(78,161,255,.35);
}

* { box-sizing: border-box; }

html, body {
  height: 100%;
  margin: 0;
  background: radial-gradient(1200px 600px at 70% -10%, #14202e 0%, var(--bg) 60%);
  color: var(--fg);
  font-family: Inter, system-ui, -apple-system, Segoe UI, Roboto, Arial, sans-serif;
  line-height: 1.5;
}

.container {
  min-height: 100%;
  display: grid;
  grid-template-rows: auto 1fr auto;
  padding: 32px 16px;
}

.header {
  text-align: center;
  margin: 32px 0 12px;
}

.logo {
  font-size: 28px;
  font-weight: 700;
  letter-spacing: .2px;
}
.logo span { color: var(--accent); }

.subtitle {
  color: var(--muted);
  margin: 6px 0 0;
  font-size: 14px;
}

.card {
  width: 100%;
  max-width: 640px;
  margin: 24px auto 0;
  padding: 28px;
  background: linear-gradient(180deg, rgba(255,255,255,.02), rgba(255,255,255,.00));
  border: 1px solid rgba(255,255,255,.08);
  border-radius: 18px;
  box-shadow: 0 20px 60px rgba(0,0,0,.35), inset 0 1px 0 rgba(255,255,255,.06);
  backdrop-filter: blur(6px);
}

.card h1 {
  margin: 0 0 8px;
  font-size: 24px;
}

.card p {
  margin: 0 0 18px;
  color: var(--muted);
}

.button {
  display: inline-block;
  padding: 12px 18px;
  border-radius: 12px;
  text-decoration: none;
  color: white;
  background: linear-gradient(180deg, var(--accent), var(--accent-strong));
  font-weight: 600;
  transition: transform .08s ease, box-shadow .2s ease, filter .2s ease;
  box-shadow: 0 10px 30px var(--ring);
  will-change: transform;
}

.button:hover {
  transform: translateY(-1px);
  filter: brightness(1.02);
  box-shadow: 0 14px 36px var(--ring);
}

.button:active {
  transform: translateY(0);
  filter: brightness(.98);
  box-shadow: 0 8px 24px var(--ring);
}

.help {
  margin-top: 16px;
  font-size: 14px;
  color: var(--muted);
}

.help summary {
  cursor: pointer;
  user-select: none;
}

.footer {
  margin-top: 48px;
  text-align: center;
  color: var(--muted);
  font-size: 12px;
}