diff --git a/docutranslate/static/index.html b/docutranslate/static/index.html
index ad1ef00..62660d9 100644
--- a/docutranslate/static/index.html
+++ b/docutranslate/static/index.html
@@ -2006,8 +2006,15 @@
                 const ifr = document.getElementById('printFrame');
                 fetch(url).then(r => {
                     const cd = r.headers.get('content-disposition') || '';
-                    const match = cd.match(/filename[^;=\n]*=['"]?([^'"\n;]+)['"]?/i);
-                    const printTitle = match ? match[1].replace(/\.[^.]+$/, '') : '';
+                    // RFC 5987: filename*=UTF-8''<percent-encoded>
+                    const extMatch = cd.match(/filename\*\s*=\s*UTF-8''([^;\s]+)/i);
+                    let printTitle = '';
+                    if (extMatch) {
+                        try { printTitle = decodeURIComponent(extMatch[1]).replace(/\.[^.]+$/, ''); } catch(e) {}
+                    } else {
+                        const plainMatch = cd.match(/filename\s*=\s*["']?([^"'\n;]+)["']?/i);
+                        if (plainMatch) printTitle = plainMatch[1].trim().replace(/\.[^.]+$/, '');
+                    }
                     return r.text().then(h => ({ h, printTitle }));
                 }).then(({ h, printTitle }) => {
                     ifr.srcdoc = h;