Update app.py

app.py

@@ -59,6 +59,10 @@ def run_script(url: str, height: int, width: int, check_b,check_h):
             print (page.text)
 
             js="""
+            function setTheme(themeName) {
+                localStorage.setItem('theme', themeName);
+                document.documentElement.className = themeName;
+            }
             function toggleTheme() {
                 console.log(localStorage.getItem('theme'))
                if (localStorage.getItem('theme') === 'theme-dark'){