#quiz {
  text-align: center;
}

#quiz h3 {
  font-weight: 600;
}

#quiz img {
  margin-top: 20px;
  margin-bottom: 20px;
}

.btn.disabled, .btn[disabled], fieldset[disabled] .btn {
  cursor: not-allowed;
  filter: alpha(opacity=65);
  -webkit-box-shadow: none;
  box-shadow: none;
  opacity: 1;
}

.logo-container {
  max-width: 600px;
  margin: 0 auto;
}
@media (max-width: 767px) {
  .logo-container {
    padding: 15px;
  }

  .btn-primary:hover, .btn-primary:active, .btn-primary:focus {
    color: #fff;
    background-color: #337ab7;
    border-color: #2e6da4;
  }
}