* { box-sizing: border-box; }
body {
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, Arial, "Hiragino Kaku Gothic ProN", Meiryo, sans-serif;
  background: #0f172a;
  color: #e2e8f0;
  margin: 0;
  padding: 0 12px;
}
.container {
  max-width: 720px;
  margin: 40px auto;
  background: #111827;
  padding: 24px;
  border-radius: 16px;
  box-shadow: 0 10px 30px rgba(0,0,0,0.3);
}
h1 {
  margin-top: 0;
  font-size: 24px;
}
.form-group { margin-bottom: 16px; }
label { display: block; margin-bottom: 6px; color: #cbd5e1; }
input[type="text"], input[type="email"], input[type="number"] {
  width: 100%;
  padding: 10px 12px;
  border-radius: 10px;
  border: 1px solid #334155;
  background: #0b1220;
  color: #e2e8f0;
}
.toggle-group { display: flex; gap: 8px; margin: 16px 0; }
.toggle-button {
  flex: 1;
  padding: 10px 12px;
  border-radius: 9999px;
  border: 1px solid #334155;
  background: #0b1220;
  color: #e2e8f0;
  cursor: pointer;
}
.toggle-button.active {
  background: #1f2937;
  border-color: #475569;
}
#sq-card {
  border: 1px dashed #334155;
  padding: 14px;
  border-radius: 8px;
  background: #0b1220;
}
.muted { color: #94a3b8; font-size: 13px; }
.total { margin: 10px 0 20px; font-weight: bold; }
#pay-button {
  width: 100%;
  padding: 12px;
  background: #2563eb;
  color: white;
  border: none;
  border-radius: 10px;
  font-size: 16px;
  cursor: pointer;
}
#pay-button[disabled] {
  opacity: 0.5;
  cursor: not-allowed;
}
#success-message {
  text-align: center;
  padding: 32px 0;
}