Color themes

[ederag]

A dark color theme would be very useful. Here is the current display in Pluto/firefox:

It seems to be set in https://github.com/pfitzseb/jl-profile.js/blob/a13f2ef7852bc1782ec180e3efd4ccef2da7ba6d/dist/profile-viewer.js#L291-L301

Workaround for Pluto (changing things only for dark mode): add this cell to the notebook

html"""
<style>
    @media (prefers-color-scheme: dark) {
        .__profiler-tooltip {                
            background-color: #333;
            border: 1px solid #777;
        }
    }
</style>
"""

I'm not familiar enough with js or css to know whether this is the right thing to do though.