[dir=ltr]{--dir:-1}[dir=rtl]{--dir:1}.book-preview{perspective:min(2000px,200vh);aspect-ratio:148/210;height:min(1135px,99vh);transform-style:preserve-3d;transform:translateX(calc(-50%*var(--dir)));cursor:pointer}.book-preview>*{width:100%;height:100%;transform-origin:calc(50% + 50%*calc(var(--dir)));transition:opacity 1s ease-in,transform 1s ease-out;position:absolute;top:0;left:0}.book-preview>.flipped{transform:rotateY(calc(180deg*var(--dir)))}.book-preview>:nth-child(odd){backface-visibility:hidden}.book-preview>:nth-child(2n){opacity:0;transform:rotateY(calc(-180deg*var(--dir)))translateX(calc(100%*var(--dir)))}.book-preview>.flipped:nth-child(2n){opacity:1;transform:rotateY(0)translateX(calc(100%*var(--dir)))}@media (max-aspect-ratio:297/210){.book-preview{width:min(49vw,800px);height:auto}}