I'm a little new to all this theming, particularly in 2013, so please bear with me.
I created a theme for SP2013. It's pretty similar to the default office one but with custom colours and a background image. Once I'd created the background image and .spcolor file, I uploaded them to a blank site, tested them out, and then used Design Manager in Sharepoint to export the branding as a WSP.
I have been successfully deploying this branding around different sites, but I have a major issue: the branding doesn't work with Subsites. There may be a way to do it which I'm not seeing, and if there is please advise, but it is not appearing in the themes list on 'Change the Look'.
I would have expected one of the following to be true:
The theme is fully inherited from the main site by the sub site, and works out of the box. - this is not the case.
The theme's existence is inherited by the sub site, but it needs to be manually activated in Change the Look. - Also not true, it does not appear in Change the Look.
The WSP needs to be uploaded and activated on the sub site, too. - Also not true; when I go into the settings of the sub site there is no 'Solutions' link so I am not able to upload the WSP - is this something that should be the case?
I wouldn't mind having to upload the WSP for every site, but not even that seems doable, so I've no idea how I deploy the theme to sub sites. Hoping someone can help me out. I'm on Sharepoint Online/Office 365. The root site collection is still on 2010 experience mode, but our SP account has been upgraded and several site collections are now on 2013.
Thanks in advance for any help.