body {
  background: url('../img/fundo.jpg') no-repeat center center fixed;
  background-size: cover;
  background-position: center calc(60% - 20px); /* ou center 40% */
}

.panel-default {
  background-color: rgba(255, 255, 255, 0.8); /* Fundo branco com transparência */
  backdrop-filter: blur(10px); /* Desfoque de 10px */
  -webkit-backdrop-filter: blur(10px); /* Suporte para navegadores WebKit */
  opacity: 0.9;
  margin-top: 30px;
}

.form-group.last { margin-bottom:0px; }

@media only screen and (max-width: 768px) {
  .panel-default {
    opacity: 1;
  }
  .input-group .form-control:last-child, .input-group-addon:last-child, .input-group-btn:first-child>.btn-group:not(:first-child)>.btn, .input-group-btn:first-child>.btn:not(:first-child), .input-group-btn:last-child>.btn, .input-group-btn:last-child>.btn-group>.btn, .input-group-btn:last-child>.dropdown-toggle{
    border-color: #000;
    height: 50px;
  }
  .input-group .form-control:not(:first-child):not(:last-child), .input-group-addon:not(:first-child):not(:last-child), .input-group-btn:not(:first-child):not(:last-child) {
    border-color: #000;
    height: 50px;
  }
  .input-group-addon:first-child {
    border-color: #000;    
  }
  .btn-block {
    height: 50px;
    text-transform: uppercase;
    font-weight: bold;
  }
    
}