body {
    background-color: #f5f5f5;
    background: url('../img/background_obras.jpg') 0 0;
    background-repeat: repeat;
    background-size: 200px 100px;
}
.form-signin {
    width: 400px;
    max-width: 100%;
    padding: 15px;
    display: block;
    margin: 0 auto;
}
  
.form-signin .form-floating:focus-within {
    z-index: 2;
}
  
.form-signin input[type="text"] {
    margin-bottom: 10px;
    border-radius: 10px;
}

.principal {
  width: 800px;
  max-width: 100%;
  padding: 15px;
  display: block;
  margin: 0 auto;
}

nav, .nav-item, .navbar, .nav-link, .dropdown, .navbar-toggler, .navbar-toggler-icon {
  color: #f5f5f5 !important;
}

.active {
  color: #f5f5f5 !important;
  font-weight: bold;
}

.btn-principal {
  font-size: 1rem;
  font-weight: bold;
  padding: 10px 20px 10px 20px;
  margin-left: 10px;
  margin-right: 10px;
  margin-top: 20px;
}