body {
    text-align: center;
    font-size: clamp(1rem, 2vw, 3rem);
    background-color: beige;
    color: #333; /* 深灰色 */
}

h1 {
    margin-top: 60px;
}

h2 {
    background-color: #f8f9fa;
    transition: background-color 0.3s;
    margin-top: 50px; /* 确保h2标签之间有一定的间距 */
    clear: both;
}

.sticky {
    position: fixed;
    top: 0;
    width: 100%;
    z-index: 1000;
    background-color: #ffffff;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
    margin-top: 50px; /* 固定时去除顶部间距 */
}

input {
    float: left;
    width: 30px;;
    height: 30px;
}

ul, li, p, i, span {
    margin: 0;
    padding: 0;
    list-style: none;
    border: 0;
}

ul {
    margin-left: 3vw;
}

li {
    float: left;
    display: block;
    text-align: center;
    width: 17vw;
}

/*p强制不换行*/
p {
    white-space: nowrap;
}

/* i的宽度为父标签的一半*/

i {
    font-size: 0.8em;
    float: left;
    width: 20%;
    display: none;
    margin-left:15%;
}

i:hover {
    color: #09f;
    cursor: pointer;
}

li:hover {
    color: wheat;
    background-color: black;
}

li {
    overflow: hidden;
    height: 80px;
}


li:hover i {
    display: block;
}

ul > li > div > i:first-of-type:hover span {
    display: block
}

span {
    display: none;
    background-color: #dddddd;
    position: absolute;
    padding: 1vw;

}

li {
    border: #3498db 1px solid;
    padding: 5px;
    margin: 1px
}

.bhr {
    clear: both;
    padding: 50px 0;
    margin-bottom: 100px;
}

.button {
    clear: both;
    font-size: 1em;
    margin: 10px auto;
    text-align: center;
    width: 20%;
    height: 2em;
    line-height: 2em;
    bottom: 0;
    right: 5%;
    position: fixed;
    border-radius: 1em;
    cursor: pointer;
    color: #eee;
    background-color: #333;

}

.button:hover {
    background-color: #f8f9fa;
    color: #1e1e2f;
}

.bu2 {
    margin-bottom: 3em;
}

.footer {
    margin-right: 20%;
    clear: both;
    width: 70%;
}

.footer span {
    display: block;
    width: 70%;
    bottom: 10px;
    position: fixed;
    padding: 10px;
}

.footer span:hover {
    color: #eee;
    background-color: #333;
}

@media screen and (max-width: 600px) {
    ul li a {
        font-size: clamp(3rem, 4vw, 5rem); /* 优化小屏幕下的字体大小 */
    }
}