Sadly that doesn’t work with Indic text. Take for example, my name:

  <div style=font-size:10em><span style=color:#e01b24>క</span><span style=color:#5e5c64>్</span><span style=color:#e66100>ర</span><span style=color:#e5a50a>ి</span><span style=color:#26a269>స</span><span style=color:#1a5fb4>్</span></div>

Ideally it’d render about the same as my manual splitting/colouring: https://temp.chrismorgan.info/%E0%B0%95%E0%B1%8D%E0%B0%B0%E0....

Now sometimes you can colour parts differently: if you stick with the inherent vowel on a conjunct, here making it LETTER KA, SIGN VIRAMA, LETTER RA, ditching the VOWEL SIGN I, then essentially the K from KA and the A from RA will be coloured LETTER KA, and the R from LETTER RA will be coloured SIGN VIRAMA. I haven’t decided yet if that’s an improvement! But this split colouring I only see in Dropflow—I’m not experiencing it in Firefox or Chromium, both of which do split Arabic colouring.