style.css

*{
    margin : 0;
    padding : 0;
    box-sizing: border-box;
}
#wrapper{
    height: 100vh;/*  to cover size of screen*/
    overflow-y: auto;
    overflow-x: hidden;
    perspective: 10px;
}
.container{
    position: relative;/* is thier is any need of this*/
    height: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    transform-style: preserve-3d ;
    z-index: -1;/* is thier is any need of this */
}
.background{
    transform: translateZ(-40px) scale(5);/* bg is fixed and forgrounf image and h1 is moving together first translate on z axise then sclae it to get the effect*/
}
.foreground{
    transform: translateZ(-20px) scale(3);/* speed:h1>fg>bg : heir value is also matters,S it start showing complete || effect all h1 br and fg moving differently */
}
.background, .foreground{
    position: absolute;
    height: 100%;
    width: 100%;
    object-fit: cover;
    z-index: -1;
}
h1{
    position: absolute;/* what if it wore relative and use external fornt by self*/
    top:5rem;
    font-size: 10rem;
    letter-spacing: 4px;
    color:white;
    text-shadow: 0 0 10px rgba(0,0,0,0.3);
}
section{
    background-color: rgb(45, 45,45);
    color:white;
    padding: 5rem 0;
}
.secheading{
    font-size: 5rem;
    padding: 0 10rem;
}
.text{
    font-size: 1.5rem;
    padding: 0 10rem;
    margin:5rem 0;
}
.bg{
    position: relative;
    width:100%;
    background-attachment: fixed;/* to fix the image  and we make others move over it*/
    background-position: center;
    background-size: cover;
    height: 500px;
}
.desc{
    position: absolute;
    background-color: white;   
    padding:0.5rem 2.5rem;
    top:50%;
    left:50%;
    transform: translateX(-50%) translateX(-50%);
    color: black;
    font-size: 3.5rem;
    font-weight: 600;
}
.bg1{
    background-image: url("sport-1.jpg");
}
.bg2{
    background-image: url("sport-2.jpg");
}
.bg3{
    background-image: url("sport-3.jpg");
}