*{
    margin: 0;
    box-sizing: border-box;
    font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
}
span,a,title{
    display: inline-block;
    text-decoration: none;
}
img{
    vertical-align: middle;
    height: auto;
    max-width: 100%;
}
li{
    font-size: 18px;
}
ul{
    padding: 0;
    list-style: none;
}
.ul1{
    position: absolute;
    display: none;
}
.btn{
    font-size: 20px;
    padding: 5px 25px;
    background-color: teal;
    color: white;
    position: relative;
    border: none;
}
.btnbox{
    margin-bottom: 40px;
    padding: 20px;
    width: 200px;
}
.second{
    position: relative;
}
.list{
    padding: 10px;
    background-color: yellow;
    color: black;
    border: 2px solid red;
    width: 154px;
}
.third{
    position: relative;
}
.ul2{
    position: absolute;
    top: -1px;
    left: 100%;
    width: 154px;
    display: none;
}
.ul3{
    position: absolute;
    top: -2px;
    left: 100%;
    width: 154px;
    display: none;
}
.btnbox:hover .ul1{
    display: block;
}
.second:hover .ul2{
    display: block;
}
.third:hover .ul3{
    display: block;
}

.txt{
    margin: 20px;
    background-color: dodgerblue;
    color: white;
    font-size: 20px;
}