body{
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
}
.container {
    position: relative;
    overflow: hidden;
    --width: 800px;
    --height: 400px;
    width: var(--width);
    height: var(--height);
}
.image {
    position: absolute;
    height: 100%;
   background: url(../img/web-development.png);
    background-size: var(--width) var(--height);
}
.image:first-child{
    right: 0;
    width: 100%;
    background-position: center left;
}
.image:last-child{
    right: 0;
    width: calc( 100% - var(--x,50%));
    background-position: center right;
    filter: grayscale(100%);
    box-shadow: inset 2px 0 0 #111, -2px 0 0 #111;
}