Bootstrap css global rule sometimes cause conflict with the email css

[tpayen]

Prerequisites

• I have searched for duplicate or closed issues
• I can recreate the issue with all plugins disabled

Describe the issue

Hi Alec
In the boostrap.min.css there is a global rule

*, ::after, ::before {
  box-sizing: border-box;
}

so this rule also impact the display of an email.
Most of the time there no issue with this rule but sometimes with advanced communicational email, this rule broke the email content.

Maybe we could add a rule like

#messagebody *, 
#messagebody ::after, 
#messagebody ::before {
  box-sizing: initial;
}

to avoid problems like that ?

What browser(s) are you seeing the problem on?

Chrome, Edge, Firefox

What version of PHP are you using?

No response

What version of Roundcube are you using?

1.6.9

JavaScript errors

No response

PHP errors

No response