Build a single CSS

Signed-off-by: Charles de Dreuille <charles.dedreuille@gmail.com>

packages/canon/.gitignore

@@ -2,4 +2,4 @@
 storybook-static
 
 # CSS output
-css
+/css

packages/canon/scripts/build-css.mjs

@@ -31,6 +31,7 @@ const componentsDir = 'src/components';
 const cssFiles = [
   { path: `${cssDir}/core.css`, newName: 'core.css' },
   { path: `${cssDir}/components.css`, newName: 'components.css' },
+  { path: `${cssDir}/styles.css`, newName: 'styles.css' },
 ];
 
 // Components files

packages/canon/src/css/styles.css

@@ -0,0 +1,18 @@
+/*
+ * Copyright 2024 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+@import './core.css';
+@import './components.css';