You appear to have the upcoming Script Editor Beta Features enabled in studio which explains the inconsistent studio editor settings between users.
These features include semantic highlighting, essentially improving readability and customization through the use of more categorized colors. The default color preset for the new editor expands upon the old default color preset which is why they appear different.
You can either deactivate this to get the old highlighting system/themes back or keep the new system and find/create a custom theme you’ll be comfortable using. I recommend doing the latter as this feature will be rolling out to everyone at some point anyway, and of course, helps you program.