pre_loading.js

const hideHeaderAndFooter = (document) => {
   const noneDisplayQuerySelectors = [
     "#shopify-section-announcement-bar",
     "#shopify-section-announcement",
     "#shopify-section-header",
     "#shopify-section-footer",
     "shop-login-button"
   ]
   noneDisplayQuerySelectors.forEach((querySelector) => {
       const element = document.querySelector(querySelector)
       if (element !== null) {
           element.style.display = "none"
           
       }
   })
}

const trimHeaderSpace = (document) => {
    const element = document.querySelector(".bodyWrap")
    if (element !== null) {
        element.style.paddingTop = "0"
    }
}

const target = document
const observer = new MutationObserver((mutations) => {
    mutations.forEach((mutation) => {
        const document = mutation.target
        hideHeaderAndFooter(document)
        trimHeaderSpace(document)
    })
})

const config = {
    subtree: true,
    characterData: true,
    childList: true
}
observer.observe(target, config)