The item() method of the StyleSheetList interface returns a single CSSStyleSheet object.
item(index)indexAn integer which is the index of the item in the collection to be returned.
A CSSStyleSheet object, or null if one does not exist for this index.
In the following example, a for loop prints each individual CSSStyleSheet object to the console, by calling item with the value of i.
let list = document.styleSheets;
for (let i = 0; i < list.length; i++) {
console.log(list.item(i));
}