I have a simple web page where on the top there´s a div with this:

<div class="divmain-login">
    <div class="divmain-sup-login">
        <div class="textos">
            <h1>Manejo de archivos</h1>
            <h2>Gaspar Giménez 2021</h2><h3>v 1.2</h3>
        </div>
    </div>
</div>

I want to have the attribute height of this block (with the class .divmain-sup-login) with this JS code:

function setDivSupHeight(){
const DivSup = document.querySelector(".divmain-sup-login");
console.log(DivSup.getAttribute("style"));

    const divh = DivSup.style.height;
    console.log(divh);
}

    setDivSupHeight();

The console returns this:

null (line 3)

nothing (line 7)

The atrribute style returns null, and this is the CSS:

.divmain-sup-login{
position: sticky;
background-color: #F56D7B;
text-align: center;
width: 100vw;


height: 90px;
    display: flex;
    flex-flow: column wrap;
    justify-content: center;
    align-content: center;
}

I dont know how can i get the height of this block.