Splash + sticky Viads

<style>
    #%DIV_ID% .__lxG__splash-counter {background-color: transparent; color: #48647F;}
    #%DIV_ID% .__lxG__splash {background-color: white}
</style>
<script>
(function() {
    var adContainerId = '%DIV_ID%';
    var parentSelector = '#' + adContainerId + '.__lxG__multi:not(.__lxG__splash-container)';
    var adContainer = document.querySelector(parentSelector);

    var viadsSelector = '.WfSayC[data-vads-ui-element="player"], div[data-vads-zone="6445"]';
    var lowerIndex = "2147483646";

    if (!adContainer) return;

    var styleTagId = 'style-for-' + adContainerId;
    if (!document.getElementById(styleTagId)) {
        var cssRules = `
            ${parentSelector} {
                visibility: hidden !important;
                opacity: 0 !important;
            }
            ${parentSelector}.splash-is-visible {
                visibility: visible !important;
                opacity: 1 !important;
            }
        `;
        var styleElement = document.createElement('style');
        styleElement.id = styleTagId;
        styleElement.innerHTML = cssRules;
        document.head.appendChild(styleElement);
    }

    var fixViadsZIndex = function() {
        var targetViads = document.querySelector(viadsSelector);
        if (targetViads) {
            targetViads.style.setProperty('--vads-player-z-index', lowerIndex, 'important');
            targetViads.style.setProperty('z-index', lowerIndex, 'important');
        }
    };

    var showContainer = function() {
        fixViadsZIndex();
        adContainer.classList.add('splash-is-visible');
    };

    if (adContainer.querySelector('.__lxG__not_empty_block')) {
        showContainer();
        return;
    }

    var observer = new MutationObserver(function(mutations) {
        fixViadsZIndex();
        if (adContainer.querySelector('.__lxG__not_empty_block')) {
            showContainer();
        }
    });

    observer.observe(document.body, {
        childList: true,
        subtree: true
    });

    fixViadsZIndex();
})();
</script>