css: stage the tailwind-built file

ci: save the generated file in the tmp folder and do a diff with the
staged file

.drone.yml

@@ -47,7 +47,9 @@ steps:
     commands:
       - pacman -Sy && pacman -S --noconfirm --needed npm
       - npm i
-      - npx tailwindcss -i ./assets/input/css/tailwind.css -o ./assets/public/css/pcmt.css --minify
+      - npx tailwindcss -i ./assets/input/css/tailwind.css -o ./tmp/pcmt.css --minify
+      # ignore whitespace changes.
+      - diff -Nsb ./assets/public/css/pcmt.css ./tmp/pcmt.css || ( echo files differ; exit 1 )
 
   - name: go build
     image: docker.io/immawanderer/archlinux-go:linux-amd64
@@ -119,7 +121,9 @@ steps:
     commands:
       - apk update -q && apk add -q --no-cache npm
       - npm i
-      - npx tailwindcss -i ./assets/input/css/tailwind.css -o ./assets/public/css/pcmt.css --minify
+      - npx tailwindcss -i ./assets/input/css/tailwind.css -o ./tmp/pcmt.css --minify
+      # ignore whitespace changes.
+      - diff -Nsb ./assets/public/css/pcmt.css ./tmp/pcmt.css || ( echo files differ; exit 1 )
 
   - name: go build
     image: docker.io/library/golang:1.20.4-alpine3.17

.gitignore

@@ -7,11 +7,6 @@ pcmt
 # air tmp dir
 /tmp
 
-# this stylesheet gets dynamically rebuilt and is therefore not a stable thing
-# to stage to git. instead, users are expected to build it before compiling and
-# running the application, using either go generate or directly using npm.
-/assets/public/css/pcmt.css
-
 Session.vim
 
 /node_modules/