#kontakt_formular input[type=text], #kontakt_formular textarea { width: 450px; resize: none; }
img.genimg { display: inline-block; vertical-align:  middle; }
#pruef { margin-top: 4px; }

@media only screen and (max-width: 780px) { 

    #kontakt_formular input[type=text], #kontakt_formular textarea { width: 100%; }
}