feat: rewrite CSS url() paths in proxy so backgrounds load

server.js

@@ -177,6 +177,10 @@ app.get('/proxy/*', async (req, res) => {
             // inject a <base> so unrewritten relative URLs default to proxy root
             html = html.replace(/<head[^>]*>/i, m => m + '\n<base href="/proxy/">');
             res.send(html);
+        } else if (ct.includes('text/css')) {
+            let css = await r.text();
+            css = css.replace(/url\(\s*(["']?)\/(?!\/)/g, 'url($1https://student.sechenov.ru/');
+            res.send(css);
         } else {
             // stream binary/text as-is
             const buf = Buffer.from(await r.arrayBuffer());