Nice work.

As these are not user editable in cassiopeia would it not be better to have them in a stylesheet instead of as an inline style. If this stylesheet was located in the /templates/system folder instead of the /templates/cassiopeia folder then it would be even better as it would be more obvious that a template developer needs to include it in their own template in order for media manager to work correctly in the front end

It's fine as inline styles, but this needs to be documented that AFFECTS every front end template.
Also, a personal preference would be to change the prefix from template to jdt (joomla design token) or something similar. The template prefix is not really representative that these are Global design tokens. But maybe that's just me.

It's fine as inline styles, but this needs to be documented that AFFECTS every front end template.

Doing it in a stylesheet will mean that it can be updated in a new release without having to ask every template developer and site owner to update their own templates.

So wouldn't this be more obvious (and useful) as every template will need it

Pseudo code untested

// Enable assets
$wa->usePreset('template.cassiopeia.' . ($this->direction === 'rtl' ? 'rtl' : 'ltr'))
	->useStyle('template.active.language')
	->useStyle('template.user')
	->useScript('template.user')
	// global design classes
	->useStyle('template.global');

So this one can be tested now as #34621 got merged.

I have tested this item ✅ successfully on d2968b5

I have tested this item ✅ successfully on d2968b5

thank you

RTC

Thanks!