css代码

/*手机侧边栏背景图片*/
@media (max-width: 767px){.mobile-navbar.show,.mobile-navbar.left{    
background-size: cover;    
background-repeat: no-repeat;    
background-position: center center;    
cursor: pointer;  background-image:linear-gradient(rgba(255, 255,255,0),rgba(255,255,255, 0.3)),url(https://img.wiiuii.cn/img/20200829145305_5a9ac.jpg);}  .mobile-nav-widget .box-body {    background: var(--muted-border-color) !important;}}

自定义图片自行更改代码中的图片地址

将代码放入主题后台自定义css框内