สอบถามเรื่อง dropdown css ผมพึ่งหัดเขียนเว็ปไม่เข้าใจว่าเกิดปัญหาจากตรงไหน

<div class="navbar">

        <ul>
            <li><a class="Z" href="#home">Home</a></li>

            <div class="drop" style="float: left;">
                <li><a href="">news</a></li>
                <div class="dropdown">
                    <a href="#">Link 1</a>
                    <a href="#">Link 2</a>
                    <a href="#">Link 3</a>
                </div>
            </div>

            <li><a href="#contact">Contact</a></li>
            <li><a href="#about">About</a></li>




            <li style="float: right;"><a href="">Log in</a></li>
        </ul>

    </div>

.navbar ul {
    list-style-type: none;
    margin: 0;
    padding: 0;
    overflow: hidden;
    background-color: #333;
    width: 100%;
}

.navbar li {
    float: left;
}

.navbar li a,
.drop {
    display: block;
    color: white;
    text-align: center;
    padding: 14px 16px;
    text-decoration: none;
}

.navbar li a:hover:not(.Z) {
    background-color: #111;
}

.Z {
    background-color: #4CAF50;
}

.drop {
    position: relative;
    display: inline-block;
}

.dropdown {
    display: none;
    position: absolute;
    right: 0;
    background-color: #f9f9f9;
    min-width: 160px;
    box-shadow: 0px 8px 16px 0px rgba(0, 0, 0, 0.2);
    z-index: 1;
}

.dropdown a {
    color: black;
    padding: 12px 16px;
    text-decoration: none;
    display: block;
}

.btn {
    background-color: #4CAF50;
    color: white;
    padding: 16px;
    font-size: 16px;
    border: none;
    cursor: pointer;
}

.dropdown a:hover {
    background-color: #f1f1f1;
}

.drop:hover .dropdown {
    display: block;
}

.drop:hover .btn {
    background-color: #3e8e41;
}