Zendesk's Feedback Tab doesn't work so well on mobile. Here's a quick way to make it's modal dialog box play a little nicer.

zendesk-please-dont-break-mobile.css

/* --------------------------------------------------------------------------------------
## Add these styles to your zendesk dropbox custom css (/agent/#/admin/dropboxes)
----------------------------------------------------------------------------------------*/

#zenbox_container {
	height: 620px;
	margin: 0 auto;
	position: relative;
	text-align: left;
	width: 100%;
	z-index:2;
}

body {
	min-width:100%;
}


/* prevent zooming on focus */
input[type='text'],
input[type='number'],
textarea {
	font-size:16px;
}

/* --------------------------------------------------------------------------------------
## Add these styles to the site/page where the tab will be located
----------------------------------------------------------------------------------------*/

#zenbox_body {
    max-width:100%!important;
}

@media only screen 
and (max-width : 638px) {
    #zenbox_container {
        width:100%!important;
    }
}


/* --------------------------------------------------------------------------------------
## If you have problems with your CMS stripping out Zendesk's inline styles, you 
   might need something like this
----------------------------------------------------------------------------------------*/
#zenbox_tab {
	background-color: #00A4E4;
	border: 1px solid #00A4E4!important;
	-webkit-transition: all 0.2s ease-in;
	-moz-transition: all 0.05s ease-in;
	transition: all 0.2s ease-in;
}
#zenbox_tab:hover {
	background-color: #1690C0!important;
}