bg-image: url('')

layout/404.pug

@@ -1,5 +1,5 @@
 - var top_img = theme.error_404.background || theme.default_top_img
-- var bg_img = `background-image: url(${url_for(top_img)})`
+- var bg_img = `background-image: url('${url_for(top_img)}')`
 
 doctype html
 html(lang=config.language data-theme=theme.display_mode)

layout/includes/header/index.pug

@@ -17,7 +17,7 @@ if page.top_img !== false
     - var top_img = page.top_img || theme.default_top_img
 
   if top_img !== false
-    - var imgSource = top_img && top_img.indexOf('/') !== -1 ? `background-image: url(${url_for(top_img)})` : `background: ${top_img}`
+    - var imgSource = top_img && top_img.indexOf('/') !== -1 ? `background-image: url('${url_for(top_img)}')` : `background: ${top_img}`
     - var bg_img = top_img ? imgSource : ''
     - var site_title = is_archive() ? _p('page.archives') : page.title || page.tag || page.category || config.title
     - var isHomeClass = is_home() ? 'full_page' : 'not-index-bg'

layout/includes/layout.pug

@@ -31,7 +31,7 @@ html(lang=config.language data-theme=theme.display_mode class=htmlClassHideAside
         if (footerBg === true)
           - var footer_bg = bg_img
         else
-          - var footer_bg = theme.footer_bg.indexOf('/') !== -1 ? `background-image: url(${url_for(footerBg)})` : `background: ${footerBg}`
+          - var footer_bg = theme.footer_bg.indexOf('/') !== -1 ? `background-image: url('${url_for(footerBg)}')` : `background: ${footerBg}`
       else
         - var footer_bg = ''