Update packages/css/css.0.1.0/opam

Author: mseri

packages/css/css.0.1.0/opam

@@ -1,5 +1,11 @@
 opam-version: "2.0"
 synopsis: "CSS parser and printer"
+description: """
+OCaml-css is an OCaml library to parse and print CSS. It can also expand namespaces and perform computations on property values.
+
+Parsing uses [Angstrom](https://github.com/inhabitedtype/angstrom/) to dynamically choose the parser when encountering a property declaration.
+
+The parser can be extended by defining additional properties."""
 maintainer: "[email protected]"
 authors: "Zoggy <[email protected]>"
 license: "GPL-3.0-only"