Text is everywhere
Almost every program reads, manipulates and prints text. CSS represents text as a string — a sequence of characters. Strings are immutable in many languages, meaning every "change" actually produces a brand new string and leaves the original alone.
body::before {
content: "★ Featured ";
color: gold;
}Common string operations
Concatenation joins two strings together. Slicing extracts a portion. Searching finds whether a substring exists. Splitting breaks a string into pieces around a separator. Replacing swaps one substring for another. These five operations cover the vast majority of real-world text work.
Formatting and templates
When you need to drop variables into a string, prefer the language's built-in template syntax over manual concatenation. It is shorter, harder to get wrong, and produces clearer code that other developers can scan in a glance.