/* reset CSS */
* {
    margin: 0;
    padding: 0;
}

ul {
    list-style: none;
}

a {
    text-decoration: none;
}

/* 1depth Menu */
ul.main_menu {
    width: 30%;
    margin: 0 auto;
}

ul.main_menu a {
    display: block;
    padding: 10px 20px;
    box-sizing: border-box;
    border: solid #ccc;
    border-width: 1px 0;
}

ul.main_menu li {
    background-color: lightgray;
    line-height: 38px;
    position: relative;
}

ul.main_menu>li {
    width: 100%;
    border-radius: 20px;
    text-align: center;
}

ul.main_menu>li>a {
    color: #333;
    background: #99f;
}

ul.main_menu>li:hover>a {
    color: #99f;
    background-color: #fff100;
}

ul.main_menu>li>a::after {
    content: ' ▼';
}

/* 2depth Menu */
ul.sub_menu {
    display: none;
    width: inherit;
    position: absolute;
    top: 0;
    right: -100%;
}

ul.sub_menu>li:hover {
    background-color: #7fbf41;
}