Styles have to be created new, but its easy to do it with a little skill. I do it this way:
Open the old css style from 6.5.x in a editor or styleeditor like Topstyle. Topstyle helps you to get an overview because it sort the classes.
Then go to Threads7, copy the default style and give it a new name. If you use graphics in the old stlye upload it to threads7/styles/images/yourname. Use full URL in the Threads7 style editor to this graphics.
Then check out the main settings in your old style. Begin with body and tdheader. lighttable and darktable will become alt-1 and alt-2 ... 75% done. Use the same settings to the left and right boxes. 85% done.
Go through all settings and set it up, takes 30minutes up to several hours according your skill.
Use Firefox in the Threads7 Style Editor so you can use the on-the-fly preview.
