Tags
Attrs does not like '/' characters in its classes, so to use some tailwind classes with custom values we must make new classes in our tailwind input css.
.cinematic { @apply aspect-[2.39/1]; }
Given the following markdown with attrs added to the image and to the paragraph block.
{.aspect-[2.39/1]} {.cinematic} {.cinematic} 
We get the following output with only the middle one working correctly.
{.aspect-[2.39/1]}
Note
The inline version of .cinematic works, but .aspect-[2.39/1] does not,
it turns into text after the image. The block version with the class
before the image applies to the paragraph, not the image.