.containerPrincipal {
    position: absolute;
    left: 50%;
    top: 50%;
    transform: translate(-50%, -50%);
    border: 1px solid blue;
    padding: 40px;
    background-color: white;
}

.containerSecundario {
    text-align: center;
}

.imgcenter {
    display: block; 
    margin-left: auto;  
    margin-right: auto;  
    width: 50%;
}

@media screen and (min-width: 992px) {
    .navbar {
      padding: 0;
    }
    .navbar .navbar-nav .nav-link {
      padding: 1em 0;
    }
    .navbar .navbar-nav .nav-item {
      margin: 0 1em;
    }
  }
  
  .navbar .navbar-nav .nav-item {
    position: relative;
  }


.navbar .navbar-nav .nav-item::after {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    margin: 0 auto;
    content: "";
    background-color: blue;
    width: 0%;
    height: 2px;
    transition: all 0.5s;
  }
  .navbar .navbar-nav .nav-item:hover::after {
    width: 100%;
  }