直接在管理后台--设置--自定义代码里填入即可,注意logo的img图片地址修改成自己的

<style>
.ui.fluid.accordion {
   background-color:unset;
}
.right.menu>a{
visibility: hidden;
}
.footer .is-size-7{
visibility: hidden;
}
.item img{
visibility: hidden;
}

</style>
<script>
window.onload = function(){
try {
   document.querySelector(".logo a").innerHTML="<img src='https://xxxxfavicon.png' width=50 height=50></img> "  //修改小图标
} catch (err) {
    console.log(err)
}
try{
var body=document.getElementsByTagName("body")[0];
//body.setAttribute('data-gridlist', window.location.pathname == '/'?'list':'grid');
}
catch (err) {
    console.log(err)
}
try {
    document.querySelector("[rel='shortcut icon']").href = "https://xxxx/favicon.png"  //小图标
} catch (err) {
    console.log(err)
}
try {
    var footer = document.querySelector("div.is-size-7")
        footer.innerHTML = "Powered by xxx"    //版权信息
        footer.style.visibility = "visible"
} catch (err) {
    console.log(err)
}
try {
    var avatar = document.querySelector(".item img")
        avatar.src = "https://xxxx.favicon.png"    //导航栏logo
        avatar.style.visibility = "visible"
} catch (err) {
    console.log(err)
}
try {
    var footer = document.querySelector("div.footer-container")
        footer.innerHTML = "Powered by xx"   //版权信息
} catch (err) {
    console.log(err)
}
try {
    var footer = document.querySelector("div.mdui-typo center p")
        footer.innerHTML = "Powered by xx"  //版权信息
} catch (err) {
    console.log(err)
}
}
</script>