.side-ad {
    position: fixed;
    top: 50%;
    transform: translateY(-50%);
    width: 100px;
    height: 370px;
    z-index: 9999;
}

.left-ad { left: var(--left-offset); }
.right-ad { right: var(--right-offset); }

.side-ad img { width: 100%; display: block; }

.side-ad-close {
    position: absolute;
    top: -10px;
    right: -10px;
    width: 22px;
    height: 22px;
    background: rgba(0,0,0,.6);
    color: #fff;
    text-align: center;
    border-radius: 50%;
    cursor: pointer;
}

@media (max-width: 1200px) {
    .fixed-side-ads { display: none; }
}