I use this css button working  background-attachment: fixed;in ipad.
    please help me.Below the link

Link is here

.home #bottom-header {
    background-attachment: fixed !important;
    background-clip: border-box;
    background-color: rgb(255, 255, 255);
    background-image: url("images/hero_bg.jpg");
    background-origin: padding-box;
    background-position: center top;
    background-repeat: no-repeat;
    background-size: 100% auto;
    height: 100%;
    position: relative;
    width: 100%;
}



Question: What is the current state of research in quantum gravity?
Answer: Approaches to Quantum Gravity: Toward a New Understanding of Space, Time and Matter by Daniele Oriti.