fix: 修復 pagination UI 顯示異常的 bug

fix: 修復 footer_img 配置不生效的 bug
improvement: 優化 背景url 的判斷
feat: 背景圖片配置不再需要添加 url()

source/css/var.styl

@@ -34,7 +34,6 @@ $font-size = hexo-config('font.global-font-size') ? convert(hexo-config('font.gl
 $code-font-size = hexo-config('font.code-font-size') ? convert(hexo-config('font.code-font-size')) : var(--global-font-size)
 $font-color = #1F2D3D
 $text-line-height = 2
-$web-bg = hexo-config('background') && unquote(hexo-config('background'))
 $index_top_img_height = hexo-config('index_top_img_height') ? convert(hexo-config('index_top_img_height')) : 100vh
 $index_site_info_top = hexo-config('index_site_info_top') ? convert(hexo-config('index_site_info_top')) : 43%
 // Global color & SVG