* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --image-comparison-slider-width: 300px;
    --image-comparison-slider-handle-width: 50px;
    --final-position_img: 50%;
    --final-position_handle: calc(50% - 25px);
}

body {
    font-family: Helvetica, sans-serif;
    width: 100%;
    min-height: 100vh;
    display: flex;
        align-items: center;
    justify-content: center;
}

#image-comparison-slider {
    position: relative;
    width: var(--image-comparison-slider-width);
    overflow: hidden;
    border-radius: 0.5rem;
    box-shadow: -7px 5px 16px 1px rgba(56, 86, 122, 0.6);
    cursor: col-resize;
}

#image-comparison-slider img {
    display: block;
    width: var(--image-comparison-slider-width);
    height: auto;
    object-fit: cover;
    pointer-events: none;
    user-select: none;
    }

    #image-comparison-slider .img-wrapper {
    position: absolute;
    top: 0;
    right: 0;
    width: 50%;
    height: 100%;
    overflow: hidden;
    z-index: 1;
    transform: translateZ(0); /* This is in order to fix a Firefox bug, related to the 3D tilt effect */
    /* transition: 0.25s cubic-bezier(.03,.98,.52,.99); */
}

#image-comparison-slider .img-wrapper img {
    position: absolute;
    top: 0;
    right: 0;
    height: 100%;
}

#image-comparison-slider .label {
    position: absolute;
    top: 1rem;
    z-index: 3;
    color: #fff;
    background-color: rgba(0, 0, 0, 0.33);
    border-radius: 0.25rem;
    padding: 0.5rem 0.75rem;
    font-size: 0.85rem;
    text-align: center;
    letter-spacing: 1px;
    user-select: none;
    opacity: 0;
    transition: 0.25s cubic-bezier(.68,.26,.58,1.22);
}

#image-comparison-slider .handle {
    position: absolute;
    top: 0;
    left: calc(50% - var(--image-comparison-slider-handle-width)/2);
    width: var(--image-comparison-slider-handle-width);
    height: 100%;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    user-select: none;
    z-index: 2;
    /* transition: 0.25s cubic-bezier(.03,.98,.52,.99); */
}

#image-comparison-slider .handle-line {
    width: 3px;
    flex-grow: 1;
    background-color: #fff;
    box-shadow: 1px 1px 5px rgb(0 0 0 / 30%);
}

#image-comparison-slider .handle-circle {
    width: var(--image-comparison-slider-handle-width);
    height: var(--image-comparison-slider-handle-width);
    color: #fff;
    border: 3px solid #fff;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: space-evenly;
    background-color: rgba(0,0,0,0.3);
    box-shadow: 1px 1px 5px rgb(0 0 0 / 30%);
}


div#ad {
    width: 300px;
    height: 250px;
    border: 1px solid gray;
    overflow: hidden;
}
.init_an {
    animation: initAdImg 2.5s ease-in-out 0s;
}

@keyframes initAdImg {
    10% {width: 80%;}
    50% {width: 16%;}
    100% {width: var(--final-position_img);}
}

.init_ani{
    animation: initAdHandle 2.5s ease-in-out 0s;
}

@keyframes initAdHandle {
    10% {left: calc(20% - 25px);}
    50% {left: calc(84% - 25px);}
    100% {left: var(--final-position_handle);}
}