add thumbnail with styling for light and dark mode (typst-community#27)

* add thumbnail with styling for light and dark mode

* replace thumbnails with SVG

Author: SillyFreak

Justfile

@@ -9,6 +9,8 @@ default:
 # generate manual
 doc:
 	typst compile docs/manual.typ docs/manual.pdf
+	typst compile docs/thumbnail.typ thumbnail-light.svg
+	typst compile --input theme=dark docs/thumbnail.typ thumbnail-dark.svg
 
 # run test suite
 test *args:

README.md

@@ -36,6 +36,11 @@ These instructions will get you a copy of the project up and running on the typs
 #my-func()
 ```
 
+<picture>
+  <source media="(prefers-color-scheme: dark)" srcset="./thumbnail-dark.svg">
+  <img src="./thumbnail-light.svg">
+</picture>
+
 ### Installation
 
 A step by step guide that will tell you how to get the development environment up and running. This should explain how to clone the repo and where to (maybe a link to the typst documentation on it), along with any pre-requisite software and installation steps.

docs/thumbnail.typ

@@ -0,0 +1,10 @@
+#import "/src/lib.typ" as my-package: *
+
+#set page(height: auto, margin: 5mm, fill: none)
+
+// style thumbnail for light and dark theme
+#let theme = sys.inputs.at("theme", default: "light")
+#set text(white) if theme == "dark"
+
+#set text(22pt)
+#align(center)[_a thumbnail showing the package's output_]