:root {
  --bg: #0f172a;
  --panel: #020617;
  --accent: #22c55e;
  --text: #e5e7eb;
  --muted: #9ca3af;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  background: radial-gradient(circle at top, #1e293b, var(--bg));
  font-family: system-ui, sans-serif;
  color: var(--text);
  display: flex;
  justify-content: center;
  align-items: center;
}

.app {
  width: 100%;
  max-width: 420px;
  background: linear-gradient(180deg, rgba(255,255,255,0.04), var(--panel));
  border-radius: 18px;
  padding: 28px;
  border: 1px solid rgba(255,255,255,0.08);
  box-shadow: 0 20px 40px rgba(0,0,0,0.5);
  animation: fadeIn 0.6s ease;
}

.header {
  margin-bottom: 20px;
}

h1 {
  margin: 0;
  color: var(--accent);
}

.subtitle {
  color: var(--muted);
  font-size: 0.9rem;
}

.card {
  margin-bottom: 20px;
}

button {
  background: linear-gradient(135deg, var(--accent), #4ade80);
  border: none;
  border-radius: 10px;
  padding: 10px 16px;
  font-weight: 600;
  cursor: pointer;
  transition: transform 0.2s, box-shadow 0.2s;
}

button:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 20px rgba(34,197,94,0.4);
}

.hidden {
  display: none;
  margin-top: 12px;
  color: var(--accent);
}

.footer {
  text-align: center;
  font-size: 0.85rem;
  color: var(--muted);
}

.footer a {
  color: var(--accent);
  text-decoration: none;
  font-weight: 600;
}

.footer a:hover {
  text-decoration: underline;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(12px); }
  to { opacity: 1; transform: translateY(0); }
}