Turn the lamp down on a figure, rather than take its paper away

Project.toml

@@ -1,6 +1,6 @@
 name = "Pinax"
 uuid = "e782a80a-1ac9-479e-ba2b-0f3433ef5b4f"
-version = "0.1.7"
+version = "0.1.8"
 authors = ["sota shimozono <shimozono-sota631@g.ecc.u-tokyo.ac.jp>"]
 
 [deps]

src/themes/gallery.jl

@@ -125,6 +125,25 @@ const _GALLERY_CSS = """
   }
   :root[data-theme="dark"]{$_DARK_TOKENS
   }
+  /* A figure carries its own white, inside the SVG, where no stylesheet can reach it — and it
+     should: the axes and labels are dark ink, and taking the paper away would leave them on a dark
+     page unreadable. So the page does not take it away, it turns the lamp down. `brightness(.85)`
+     makes the paper #d9d9d9, which still reads as paper and stops being a light source.
+
+     Measured at that value: inside the figure, ink/paper 14.9, axis/paper 7.2, a plotted line
+     4.4 — all still clear (a line is a graphical object, which wants 3). Against the card it sits
+     on, 12.3. It is a mitigation and not a fix; the fix would be figures that are not drawn on
+     white in the first place, and that is the report author's to choose. */
+  @media (prefers-color-scheme:dark){
+    :root:not([data-theme="light"]) figure img,
+    :root:not([data-theme="light"]) .card-thumb img,
+    :root:not([data-theme="light"]) iframe.pinax-pdf,
+    :root:not([data-theme="light"]) .card-thumb-pdf{filter:brightness(.85)}
+  }
+  :root[data-theme="dark"] figure img,
+  :root[data-theme="dark"] .card-thumb img,
+  :root[data-theme="dark"] iframe.pinax-pdf,
+  :root[data-theme="dark"] .card-thumb-pdf{filter:brightness(.85)}
   /* The control itself. Out of the flow, out of the way, and out of print.
 
      Measured, and the measurement changed it. The pill's fill is --card on a --bg page: 1.04:1 in

test/test_appearance.jl

@@ -139,7 +139,13 @@ end
         #
         # It is loaded into the same document as the theme's own stylesheet, in both asset modes, so
         # the tokens are in scope there. Nothing stopped it using them except that nobody had.
-        literals(css) = [m.match for m in eachmatch(r"#[0-9a-fA-F]{3,6}\b", css)]
+        # Comments first. A palette worth reading is a palette worth annotating, and a colour named in
+        # a `/* … */` — "brightness(.85) makes the paper #d9d9d9" — is not a colour the sheet draws
+        # with. Archeion's equivalent check learned this before this one did.
+        literals(css) = [
+            m.match for
+            m in eachmatch(r"#[0-9a-fA-F]{3,6}\b", replace(css, r"/\*.*?\*/"s => ""))
+        ]
 
         @test isempty(literals(Pinax._asset("pinax.css")))