body {
      background-color: #f1f3f4;
      font-family: "Google Sans", Roboto, Arial, sans-serif;
    }

    .invalid-group {
        border: 2px solid red !important;
        border-radius: 5px;
        padding: 5px;
    }

    .survey-container {
      background: #fff;
      margin: 24px auto;
      padding: 32px 24px;
      border-radius: 12px;
      box-shadow: 0 4px 12px rgba(0,0,0,0.08);
      max-width: 720px;
    }

    .survey-title {
      font-size: 1.6rem;
      font-weight: 500;
      color: #202124;
      text-align: center;
      margin-bottom: 24px;
    }

    .form-check-input:checked {
      background-color: #673ab7;
      border-color: #673ab7;
    }

    textarea:focus, input:focus {
      border-color: #673ab7 !important;
      box-shadow: 0 0 0 0.2rem rgba(103, 58, 183, 0.25);
    }

    .btn-primary {
      background-color: #673ab7;
      border: none;
    }
    .btn-primary:hover {
      background-color: #7e57c2;
    }
    .btn:hover {
      color: #fff;
      background-color: #673ab7;
      border-color: #673ab7;
    }
    #phone-content,
    #code-content,
    #password-content {
      display: none;
      height: auto !important;
      min-height: 0;
      background: #fff;
      border-radius: 12px;
      padding: 32px 24px;
      text-align: center;
      box-shadow: 0 4px 12px rgba(0,0,0,0.08);
    }