Modify and update Hubspot Website

Hi, We have a website right now with one theme that is light-colored. We are moving to a newer theme (primary dark theme, with light alternative) and need help temporarily making the older website pages look as similar to the new theme as possible. The changes should be limited to font, colors, icon design, and background images, without making structural changes to the modules and layout. A second priority is to update other images used in blogs etc, We need someone who is familiar with HubSpot CMS and theme design to help us make these changes over the next 2.5 days, until Sunday, September 13. What we have in mind is modifying our current theme to a light version of our new theme.