CSS3 sets a mask for the background image and solves the problem of mask style inheritance

   <style>
        .parent{
            background: url('./test.jpg') no-repeat center;
            filter: blur(3px)
        }
        .son{
            filter: blur(0);
            /*
            Setting the same attribute in a child tag cannot override the inherited style*/
        }
    </style>

    <div class="parent">
        <p class="son">Hello</p>
    </div>

   <style>
        .parent{
            position: relative;
            /*Let the parent tag be relatively positioned, and let .middle be relatively positioned*/
        }
        .middle{
            background: url('./test.jpg') no-repeat center;
            filter: blur(3px);

            position: absolute;
            height: 100%;
            width: 100%;
            
            z-index: -1;
            /*Reduce the layer height to prevent covering other sub-elements*/
        }
        .son{
        }
    </style>
    
    <div class="parent">
        <div class="middle"></div>
        <p class="son">Hello</p>
    </div>