1. I just started self-study and wanted to add a background to the title, but I got an error

2.html code:

<p id="container">
           <p id="header">
              <p id="Love Live Sunshine">
                  <p>
                                    <h1>Love Live Sunshine</h1>
                                    <hr width="960&">
                                    <p>这是一个标题！！！</p>
                  </p>
               </p> 
            </p>

3.CSS code:

#header{
    margin: 0;
    width: 100%;
    background: url(网站图片资源/LLSS.jpg);
    background: no-repeat;
    background: center;
}

Thank you all in advance (ง •_•)ง