.book { border: 7px solid black; background-color: white; border-radius: 15px; padding: 0 4px; width: 500px; /* adjust size */ max-width: 100%; aspect-ratio: 3 / 2; display: flex; } .pageL, .pageR { height: 100%; width: 50%; display: inline-block; position: relative; border-radius: 10px; wafasdf } .pageL { border-left: 1px grey solid; } .pageR { border-right: 1px grey solid; lorume } .seam { width: 7px; background: linear-gradient(to right, white, grey, white);