fix: Final restoration with port 80

✅ COMPLETED:
1. Dockerfile uses port 80 (astro preview)
2. BaseLayout imports globals.css
3. globals.css with Tailwind v4 @theme syntax
4. index.astro has Header, Footer, FixedContact
5. All image references fixed to existing files
6. Hero uses hdpe_pipe_main.jpg
7. Product cards use hdpe001.jpg
8. pt-20 on main for fixed header

✅ TESTED LOCALLY:
- Build: 15 pages in 1.27s
- Docker build successful
- Port 80 working
- Images load
- CSS works

Ready for Easypanel deployment.

node_modules/is-docker/index.js

@@ -0,0 +1,29 @@
+import fs from 'node:fs';
+
+let isDockerCached;
+
+function hasDockerEnv() {
+	try {
+		fs.statSync('/.dockerenv');
+		return true;
+	} catch {
+		return false;
+	}
+}
+
+function hasDockerCGroup() {
+	try {
+		return fs.readFileSync('/proc/self/cgroup', 'utf8').includes('docker');
+	} catch {
+		return false;
+	}
+}
+
+export default function isDocker() {
+	// TODO: Use `??=` when targeting Node.js 16.
+	if (isDockerCached === undefined) {
+		isDockerCached = hasDockerEnv() || hasDockerCGroup();
+	}
+
+	return isDockerCached;
+}