diff --git a/lib/classroom_style.py b/lib/classroom_style.py
new file mode 100644
index 0000000..b80199e
--- /dev/null
+++ b/lib/classroom_style.py
@@ -0,0 +1,35 @@
+"""The classroom stylesheet, resolved at the room's UI scale.
+
+The dock and the DVD control bar share this so they cannot drift apart:
+one template, one set of measurements, one look.
+"""
+
+from pathlib import Path
+
+from classroom_config import scaled
+
+TEMPLATE = Path("/etc/ekklesia-classroom/dock/style.css.in")
+
+# Every measurement in the template, at UI_SCALE=1.0.
+MEASUREMENTS = {
+    "dock-radius": 24,
+    "dock-padding-v": 8,
+    "dock-padding-h": 10,
+    "button-radius": 16,
+    "button-padding": 6,
+    "button-size": 44,
+    "clock-radius": 16,
+    "clock-padding-v": 7,
+    "clock-padding-h": 12,
+    "clock-font": 17,
+}
+
+
+def render(scale, template=None):
+    """Resolve the measurement tokens in the stylesheet template."""
+    css = (template or TEMPLATE).read_text()
+
+    for token, value in MEASUREMENTS.items():
+        css = css.replace(f"@{token}@", str(scaled(value, scale)))
+
+    return css
diff --git a/scripts/classroom-dock b/scripts/classroom-dock
index ed38524..6bf6723 100755
--- a/scripts/classroom-dock
+++ b/scripts/classroom-dock
@@ -14,6 +14,7 @@ from gi.repository import Gtk, Gdk, GdkPixbuf, GLib, GtkLayerShell
 
 sys.path.insert(0, "/usr/local/lib/ekklesia-classroom")
 
+import classroom_style as style  # noqa: E402
 from classroom_config import (  # noqa: E402
     enabled,
     read_device_config,
@@ -30,7 +31,6 @@ except ImportError:
     optical = None
 
 
-CSS_FILE = Path("/etc/ekklesia-classroom/dock/style.css.in")
 ICON_DIR = Path("/etc/ekklesia-classroom/icons")
 
 DVD_POLL_SECONDS = 2
@@ -358,39 +358,13 @@ class ClassroomShell(Gtk.Window):
         return True
 
 
-def render_css(scale):
-    """Resolve the measurement tokens in the stylesheet template."""
-    css = CSS_FILE.read_text()
-
-    measurements = {
-        "dock-radius": 24,
-        "dock-padding-v": 8,
-        "dock-padding-h": 10,
-        "button-radius": 16,
-        "button-padding": 6,
-        "button-size": 44,
-        "clock-radius": 16,
-        "clock-padding-v": 7,
-        "clock-padding-h": 12,
-        "clock-font": 17,
-    }
-
-    for token, value in measurements.items():
-        css = css.replace(
-            f"@{token}@",
-            str(scaled(value, scale)),
-        )
-
-    return css
-
-
 def load_css(scale):
     # Styling is worth losing before the dock is. A stylesheet that will
     # not parse leaves an unstyled but working shell rather than no shell.
     try:
         provider = Gtk.CssProvider()
         provider.load_from_data(
-            render_css(scale).encode("utf-8")
+            style.render(scale).encode("utf-8")
         )
     except (OSError, GLib.Error) as error:
         print(