.construction{
    height: 100vh;
}
.logo_sa{
    height: 150px;
}
.construction .btn_sa{
    cursor: pointer;
    color: #fff;
    background-color: #000;
    border: #fff;
}
.construction .btn_sa:hover{
    background-color: #dddddd;
    color: #000;
    border: #000;
}