Contact Form created on top of Fullwidth Easy Slider moves off page

I created a contact form that appears over the easy slider. It looks absolutely perfect in Chrome. And that’s the only place. It’s moved way, way to the right in Firefox, Edge, and Safari. Is there an additional bit of CSS that I can use for Edge, Firefox, and Safari? Or can you correct my CSS below:

/* Contact form over slider */
#signup {
position: absolute !important;
padding-top:10%;
top: 100px;
left: 800px;
right: 20px;
float: right;
z-index:99999!important;
}

Thank you.