CSS – move from theme editor to Built in cSS

Hi i have put the code directly into the theme editor. Can I move it to the built in editor without loosing the content in the footer? I was thinking of doing it as follows:
1) copy the code from the theme editor to the built in editor
2) delete the code in the theme editor.

Regards

#footer-sidebar {
display:block;
height: auto;
}
#footer-sidebar1 {
float: left;
border: 1px solid #fff;
border-radius: 20px;
width: 700px;
margin-left:5px;
margin-right:5px;
background-color: #ffffff;
}
#footer-sidebar2 {
float: left;
border: 1px solid #fff;
border-radius: 20px;
width: 100%;
margin-left:5px;
margin-right:5px;
background-color: #fdfbb7;
}
#footer-sidebar3 {
float: left;
border: 1px solid #fff;
border-radius: 20px;
width: 100%;
margin-left:5px;
margin-right: 5px;
background-color: #193549;
color: #ffffff
}