diff --git a/.copier-answers.yaml b/.copier-answers.yaml
index 55bbacc..971e12c 100644
--- a/.copier-answers.yaml
+++ b/.copier-answers.yaml
@@ -1,5 +1,5 @@
 # Changes here will be overwritten by Copier
-_commit: 9be318c
+_commit: '1246721'
 _src_path: https://github.com/python-project-templates/base.git
 add_docs: true
 add_extension: js
diff --git a/.gitattributes b/.gitattributes
index bb7085b..aaf2698 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -7,7 +7,6 @@ Makefile linguist-documentation
 *.html text=auto eol=lf
 *.js text=auto eol=lf
 *.json text=auto eol=lf
-*.less text=auto eol=lf
 *.md text=auto eol=lf
 *.py text=auto eol=lf
 *.toml text=auto eol=lf
diff --git a/js/build.mjs b/js/build.mjs
index 0efb9eb..942cfef 100644
--- a/js/build.mjs
+++ b/js/build.mjs
@@ -1,10 +1,9 @@
 import { NodeModulesExternal } from "@finos/perspective-esbuild-plugin/external.js";
 import { build } from "@finos/perspective-esbuild-plugin/build.js";
-import { BuildCss } from "@prospective.co/procss/target/cjs/procss.js";
+import { transform } from "lightningcss";
 import { getarg } from "./tools/getarg.mjs";
 import fs from "fs";
 import cpy from "cpy";
-import path_mod from "path";
 
 const DEBUG = getarg("--debug");
 
@@ -40,31 +39,29 @@ const BUILD = [
 
 async function compile_css() {
   const process_path = (path) => {
-    const outpath = path.replace("src/less", "dist/css");
+    const outpath = path.replace("src/css", "dist/css");
     fs.mkdirSync(outpath, { recursive: true });
 
-    fs.readdirSync(path).forEach((file_or_folder) => {
-      if (file_or_folder.endsWith(".less")) {
-        const outfile = file_or_folder.replace(".less", ".css");
-        const builder = new BuildCss("");
-        builder.add(
-          `${path}/${file_or_folder}`,
-          fs
-            .readFileSync(path_mod.join(`${path}/${file_or_folder}`))
-            .toString(),
-        );
-        fs.writeFileSync(
-          `${path.replace("src/less", "dist/css")}/${outfile}`,
-          builder.compile().get(outfile),
-        );
-      } else {
-        process_path(`${path}/${file_or_folder}`);
+    fs.readdirSync(path, { withFileTypes: true }).forEach((entry) => {
+      const input = `${path}/${entry.name}`;
+      const output = `${outpath}/${entry.name}`;
+
+      if (entry.isDirectory()) {
+        process_path(input);
+      } else if (entry.isFile() && entry.name.endsWith(".css")) {
+        const source = fs.readFileSync(input);
+        const { code } = transform({
+          filename: entry.name,
+          code: source,
+          minify: !DEBUG,
+          sourceMap: false,
+        });
+        fs.writeFileSync(output, code);
       }
     });
   };
-  // recursively process all less files in src/less
-  process_path("src/less");
-  cpy("src/css/*", "dist/css/");
+
+  process_path("src/css");
 }
 
 async function copy_html() {
diff --git a/js/package.json b/js/package.json
index 0f4d55a..709f62c 100644
--- a/js/package.json
+++ b/js/package.json
@@ -30,23 +30,30 @@
     "build": "node build.mjs",
     "clean": "rm -rf dist playwright-report ../python_template_js/extension",
     "dev": "npm-run-all -p start watch",
-    "lint": "prettier --check \"src/**/*.{js,ts,jsx,tsx,less,css}\" \"tests/**/*.{js,ts,jsx,tsx}\" \"*.mjs\" \"*.json\"",
-    "fix": "prettier  --write \"src/**/*.{js,ts,jsx,tsx,less,css}\" \"tests/**/*.{js,ts,jsx,tsx}\" \"*.mjs\" \"*.json\"",
+    "lint": "prettier --check \"src/**/*.{js,ts,jsx,tsx,css}\" \"tests/**/*.{js,ts,jsx,tsx}\" \"*.mjs\" \"*.json\"",
+    "fix": "prettier  --write \"src/**/*.{js,ts,jsx,tsx,css}\" \"tests/**/*.{js,ts,jsx,tsx}\" \"*.mjs\" \"*.json\"",
     "preinstall": "npx only-allow pnpm",
     "prepack": "npm run build",
     "start": "http-server -p 3000 -o examples/",
     "start:tests": "http-server -p 3000 ",
     "test": "TZ=UTC playwright test",
-    "watch": "nodemon --watch src -e ts,less,html --exec \"pnpm build:debug\""
+    "watch": "nodemon --watch src -e ts,css,html --exec \"pnpm build:debug\""
   },
   "dependencies": {},
   "devDependencies": {
     "@finos/perspective-esbuild-plugin": "^3.2.1",
+<<<<<<< before updating
     "@playwright/test": "^1.58.2",
     "@prospective.co/procss": "^0.1.18",
     "cpy": "^13.2.1",
     "esbuild": "^0.27.2",
     "esbuild-plugin-less": "^1.3.36",
+=======
+    "@playwright/test": "^1.56.1",
+    "cpy": "^12.1.0",
+    "esbuild": "^0.27.2",
+    "lightningcss": "^1.29.3",
+>>>>>>> after updating
     "http-server": "^14.1.1",
     "nodemon": "^3.1.14",
     "npm-run-all": "^4.1.5",
diff --git a/js/src/less/index.less b/js/src/css/index.css
similarity index 100%
rename from js/src/less/index.less
rename to js/src/css/index.css