Hi Jennifer,
You'll need to adjust the css for each of the media queries (for different screen sizes). So add the following into either your custom.css file (in the css folder of your theme files) or the Quick CSS in your Styling tab of the theme options:
#top.left_sidebar #header {
margin-left: 280px;
}
@media only screen and (min-width: 768px) and (max-width: 989px) {
#top.left_sidebar #header { margin-left: 218px; }
}
@media only screen and (max-width: 767px) {
#top.left_sidebar #header, #top.left_sidebar .small_footer {margin-left: -44px;background-repeat: no-repeat;}
}
Because you used a background image for the logo, I had to add a no-repeat for the smaller sizes. Also, you have some incorrect css in your Quick CSS it looks like where you put in the background image. There is a space between your margin amount the px which was causing it not to take effect.
Regards,
Devin