* { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --primary: #667eea;
  --primary-light: #667eea18;
  --primary-border: #667eea33;
  --radius: 14px;
  --text: #1a1a1a;
  --muted: #888;
  --border: #e5e5e5;
  --bg: #f5f6fa;
  --card: #fff;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'PingFang SC', sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
}

.hidden { display: none !important; }

.btn {
  padding: 12px 28px;
  background: var(--primary);
  color: #fff;
  border: none;
  border-radius: var(--radius);
  font-size: 15px;
  font-weight: 600;
  cursor: pointer;
}
.btn:disabled { opacity: 0.5; cursor: not-allowed; }

.center {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 14px;
  text-align: center;
  padding: 24px;
}

.spinner {
  width: 34px;
  height: 34px;
  border: 3px solid #e0e0e0;
  border-top-color: var(--primary);
  border-radius: 50%;
  animation: spin 0.75s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

.err { color: #ff3b30; font-size: 13px; margin-top: 6px; }