body {
   margin: 0;
}
.login-page, .register-page {
   -ms-flex-align: center;
   align-items: center;
   background-color: #e9ecef;
   display: -ms-flexbox;
   display: flex ;
   -ms-flex-direction: column;
   flex-direction: column;
   height: 100vh;
   -ms-flex-pack: center;
   justify-content: center;
}
.card {
   background-color: transparent !important;
   box-shadow: none;
}
.login-card-body, .register-card-body {
   background-color: transparent !important;
}
.card-body img {
   width: 200px;
   display: block;
}
.login-logo, .register-logo {
   font-size: 1.4rem;
}
.login-logo, .register-logo {
   margin-bottom: 0;
}
#div_back {
   position: absolute;
   border: 0 solid silver;
   top: 10px;
   left: 10px;
}
#a_back {
   color: #676464;
   border: none;
   background-color: transparent;
   font-size: 110%;
}