Minifying CSS shrinks the file size without changing how the browser interprets it — the styles stay exactly the same, and only the parts that existed purely for human readability disappear.
What actually gets removed
A minifier strips whitespace and line breaks between rules, comments like /* ... */, the trailing semicolon before a block's closing brace, and shortens redundant zeros in values like 0.5em → .5em. None of that touches actual character content — only the whitespace and punctuation around it.
Non-ASCII content survives minification untouched
A rule like content: "→" or a custom property name with accented characters passes through minification unchanged — the tool only manipulates whitespace, comments, and syntax, not the byte encoding of the text itself. The one real gotcha is older tooling and editors that still default to Latin-1 or don't infer UTF-8 correctly when concatenating files: a CSS file with non-ASCII characters is safest served with an explicit @charset "UTF-8"; as its very first line, since that declaration has to appear before anything else in the file, including comments.
Why a minified file works exactly the same
The browser's CSS parser completely ignores whitespace and line breaks between tokens — they only exist to make the code easier for a human to read. So removing those characters doesn't change the computed styles at all, it just makes the file more compact and nearly unreadable.
Why you'd need this
- Shrink a CSS file's size before shipping a site to production.
- Speed up page load by reducing the amount of data transferred.
- Make casual inspection of the source code less revealing of the style structure.
Why byte savings matter differently depending on the audience
Where a site's visitors mostly sit on fast fixed broadband or unlimited fiber plans, shaving a few kilobytes off a CSS file barely registers for the end user — the bigger win there is usually lower CDN egress and server bandwidth costs at scale. Where a meaningful share of traffic comes from markets with slower or metered mobile connections, that same handful of kilobytes translates more directly into a faster, cheaper page load for the person on the other end. Minification is cheap enough to apply either way, but knowing which case applies helps decide how much effort is worth spending chasing it further.