Static file
A file like CSS, JavaScript, or an image that the server sends to the browser unchanged.
Static files don't change per visitor, so the server sends them exactly as they are — no code runs to build them. In Flask they live in a static/ folder, separate from the templates that Python fills in.
Link to them with url_for("static", filename="style.css") rather than hardcoding the path, so the URL stays correct even if the app moves.
<link rel="stylesheet"
href="{{ url_for('static', filename='style.css') }}">
Where this shows up in real Python
Static files are the CSS, JavaScript, and images a site serves unchanged — the parts that make pages look and behave the way they do.
Commonly used Static file tools
static/ folder— where CSS, JS, and images liveurl_for('static', filename='main.css')— build a static URLlink / script / img— the tags that load them
Official documentation: Flask Documentation: Static Files