deps: Add Chroma dark/light mode support

Closes #15017

testscripts/commands/gen.txt

@@ -8,27 +8,3 @@ hugo gen man -h
 stdout 'up-to-date man pages'
 hugo gen man --dir manpages
 
-hugo gen chromastyles -h
-stdout 'Generate CSS stylesheet for the Chroma code highlighter'
-hugo gen chromastyles --style monokai
-stdout 'Generated using: hugo gen chromastyles --style monokai'
-! hugo gen chromastyles --style __invalid_style__
-stderr 'invalid style: __invalid_style__'
-
-# Not empty classes.
-# From Hugo 0.149.0 empty classes are always removed, so no need for the omitEmpty flag.
-hugo gen chromastyles --style monokai
-! stdout '{  }'
-hugo gen chromastyles --omitEmpty --style monokai --logLevel info
-stderr 'deprecated: --omitEmpty was deprecated'
-
-# Keep same-colour token classes in generated CSS. This is needed when pairing
-# styles such as github and github-dark in dual-theme sites.
-hugo gen chromastyles --style github-dark
-stdout 'NameOther.*\.chroma \.nx \{ color:#e6edf3 \}'
-
-# Disable class comments.
-hugo gen chromastyles --style monokai
-stdout 'GenericSubheading'
-hugo gen chromastyles --omitClassComments --style monokai
-! stdout 'GenericSubheading'

testscripts/commands/gen_chromastyles.txt

@@ -0,0 +1,25 @@
+hugo gen chromastyles -h
+stdout 'Generate CSS stylesheet for the Chroma code highlighter'
+hugo gen chromastyles --style monokai
+stdout 'Generated using: hugo gen chromastyles --style monokai'
+! hugo gen chromastyles --style __invalid_style__
+stderr 'invalid style: __invalid_style__'
+
+# Not empty classes.
+# From Hugo 0.149.0 empty classes are always removed, so no need for the omitEmpty flag.
+hugo gen chromastyles --style monokai
+! stdout '{  }'
+hugo gen chromastyles --omitEmpty --style monokai --logLevel info
+stderr 'deprecated: --omitEmpty was deprecated'
+
+# Keep same-colour token classes in generated CSS. This is needed when pairing
+# styles such as github and github-dark in dual-theme sites.
+hugo gen chromastyles --style github-dark
+stdout 'NameOther.*\.chroma \.nx \{ color:#e6edf3 \}'
+
+# Disable class comments.
+hugo gen chromastyles --style monokai
+stdout 'GenericSubheading'
+hugo gen chromastyles --omitClassComments --style monokai
+! stdout 'GenericSubheading'
+

testscripts/commands/gen_chromastyles_mode.txt

@@ -0,0 +1,24 @@
+# Dark mode, no mode selector: plain ".chroma" selectors.
+hugo gen chromastyles --style github --mode dark
+stdout '\.chroma'
+! stdout '\.dark'
+
+# Dark mode for style with no dark mode.
+! hugo gen chromastyles --style friendly --mode dark
+stderr 'style "friendly" does not have a "dark" mode'
+
+# Dark mode with mode selector: ".dark .chroma".
+hugo gen chromastyles --style github --mode dark --modeSelector
+stdout '\.dark \.chroma'
+
+# Light mode with mode selector: ".light .chroma".
+hugo gen chromastyles --style github --mode light --modeSelector
+stdout '\.light \.chroma'
+
+# --modeSelector without --mode on a default light style.
+hugo gen chromastyles --style github --modeSelector
+stdout '\.light \.chroma'
+
+# --modeSelector without --mode on a default dark style.
+hugo gen chromastyles --style ashen --modeSelector
+stdout '\.dark \.chroma'