:root {
  color-scheme: light dark;
  --bg: #0f1419;
  --card: #1a2332;
  --text: #e8eef4;
  --muted: #8b9cb0;
  --accent: #009ee3;
  --accent-hover: #33b4eb;
  --ok: #00a650;
  --bad: #f23d4c;
  --warn: #ffbe00;
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}

@media (prefers-color-scheme: light) {
  :root {
    --bg: #f0f4f8;
    --card: #fff;
    --text: #1a2b3c;
    --muted: #5a6f82;
  }
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  display: grid;
  place-items: center;
  background: var(--bg);
  color: var(--text);
  line-height: 1.5;
}

.card {
  width: 100%;
  max-width: 28rem;
  padding: 2rem;
  background: var(--card);
  border-radius: 12px;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.2);
}

h1 {
  margin: 0 0 1rem;
  font-size: 1.35rem;
  font-weight: 600;
}

.amount {
  font-size: 2rem;
  font-weight: 700;
  margin: 0 0 1rem;
}

.currency {
  font-weight: 600;
  font-size: 1rem;
  vertical-align: middle;
  color: var(--muted);
}

.hint,
.subtle {
  color: var(--muted);
  font-size: 0.9rem;
  margin: 0 0 1.25rem;
}

.btn {
  display: inline-block;
  width: 100%;
  padding: 0.85rem 1.25rem;
  font-size: 1rem;
  font-weight: 600;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  transition: background 0.15s ease;
}

.btn.primary {
  background: var(--accent);
  color: #fff;
}

.btn.primary:hover:not(:disabled) {
  background: var(--accent-hover);
}

.btn:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

.error {
  color: var(--bad);
  margin-top: 1rem;
  font-size: 0.9rem;
}

.message {
  font-size: 1.05rem;
  margin: 0 0 0.75rem;
}

.message.ok {
  color: var(--ok);
}

.message.bad {
  color: var(--bad);
}

.message.warn {
  color: var(--warn);
}

.details {
  font-size: 0.85rem;
  word-break: break-all;
}

.link {
  color: var(--accent);
  text-decoration: none;
}

.link:hover {
  text-decoration: underline;
}