Add CSS selectors, CSS content attribute, SVG images, base64 images

[rootwork]

Examples:

• ::before and ::after selectors
• content: attribute
• SVG images, inline or linked
• inline base64 images

Here are some resources I found when looking these up (after not being able to find them in your chart):

https://www.caniemail.com/search/?s=before https://css-tricks.com/a-guide-on-svg-support-in-email/ https://www.campaignmonitor.com/blog/email-marketing/embedded-images-in-html-email/

Thanks for keeping this updated!

[rootwork]

Sorry, didn't see #4 until I posted this. So just consider this a request for the last three items :)