* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}
.app {
    width: 100%;
    height: 100vh;
    overflow: hidden;
    display: flex;
    justify-content: center;
    padding-top: 50px;

}
.dropdown {
    position: relative;
    width: 400px;

}
.dropdown.open .dropdown__menu {
    display: block;
}
.dropdown__label {
    padding: 5px 10px;
    border-radius: 5px;
    border: 1px solid black;
    width: 100%;
    cursor: pointer;
}
.dropdown__menu {
    list-style: none;
    display: none;
    border-radius: 5px;
    border: 1px solid black;
    position: absolute;
    width: 100%;
    top: 30px;
    padding: 10px 0;
}
.dropdown__menu li {
    padding: 5px 10px;
}
.dropdown__menu li:hover {
    background: rgba(0, 0, 0, 0.3);
    cursor: pointer;
}