Describe the bug

Background images don't load when URLs include special characters like ( and ), likely because the CSS url() function cannot properly parse unescaped characters.

Without parenthesis:

With parenthesis:

Minimal reproduction

---
theme: default
background: https://avatars.githubusercontent.com/u/47820549?id=(1234)
---

hello world

Environment

• Slidev version: 52.0.0
• Browser: Firefox 140.0.1
• OS: Ubuntu 24.04.2 LTS