Use a faster hash function

We probably don't need to be using something that's cryptographically secure (i.e., SHA-1). Instead, we could opt for a faster hash function (like Murmur) or use a checksum (like Adler-32 or CRC32).

For example, React uses Adler-32 to verify that server-generated markup matches client-generated markup (for server-side rendering).

No files, tests, or entry points are named. Start by locating where SHA-1 is used for generated CSS class hashing, then compare the proposed Murmur, Adler-32, and CRC32 alternatives against the required matching behavior and define completion around preserving correctness with a faster choice.

Written by the indexing model from the issue text.