why there is left padding and margin top for ul(flex) in header (flex)

Question

i want to give a vertical navbar , and contents should be on left

////   ITS HTML //// 
enter image description here<section class="header2">
            <ul>
                <li> <a> Home </a> </li>
                <li> <a> Explore </a> </li>
                <li> <a> About </a> </li>
                <li> <a> Contact</a> </li>
            </ul>
        </section>



///// ITS CSS ////
.header2
{
    display: flex;
    margin: 0;padding: 0;
}
.header2 ul
{
    display: flex;
    flex-direction: column;
    row-gap: 20px;
    background-color: grey; 
    height: 100%; 
    width: fit-content;
    align-items: flex-start;
    align-content: flex-start;
    justify-content: flex-start;
}

i want to give no left padding for ul and no margin top for ul , simple its content should be on left side