.banner {
    text-align: center;
    background-size: cover;
    height: 300px;
    width: 100%;
    margin-bottom: 3em;
    display: table;
}

.banner-head {
    display: table-cell;
    vertical-align: middle;
    margin-bottom: 0;
    font-size: 2em;
    color: white;
    font-weight: 500;
    text-shadow: 0 1px 1px black;
}

#main-sztokfisz {
    background: transparent url('img/slider1.jpg') 0 0 no-repeat fixed;
    text-align: center;
    background-size: cover;
    height: 300px;
    width: 100%;
    margin-bottom: 3em;
    display: table;
}

#main-o-nas {
    background: transparent url('img/onas.jpg') 0 0 no-repeat fixed;
    text-align: center;
    background-size: cover;
    height: 300px;
    width: 100%;
    margin-bottom: 3em;
    display: table;
}

#main-realizacje {
    background: transparent url('img/realizacje.jpg') 0 0 no-repeat fixed;
    text-align: center;
    background-size: cover;
    height: 300px;
    width: 100%;
    margin-bottom: 3em;
    display: table;
}

#main-oferta {
    background: transparent url('img/oferta.jpg') 0 0 no-repeat fixed;
    text-align: center;
    background-size: cover;
    height: 300px;
    width: 100%;
    margin-bottom: 3em;
    display: table;
}
#main-kontakt {
    background: transparent url('') 0 0 no-repeat fixed;
    text-align: center;
    background-size: cover;
    height: 300px;
    width: 100%;
    margin-bottom: 3em;
    display: table;
}