html {
    font-size: 21px; 
    height: 100%;
}
body {
    font-family: Microsoft Yahei, Arial, sans-serif;
    margin: 0;
    padding: 0;
    background-color: #fff;
    box-sizing: border-box;
}
.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    background-color: #fff;
    padding: 12px 24px;
    box-shadow: 0 7px 9px rgba(0, 0, 0, 0.5);
    position: relative;
}
.nav-links {
    display: flex;
    gap: 1.2em;
}

.nav-links a {
   text-decoration: none;
   color: #6a859c;
   font-size: 1.2em;
}
.nav-links a:hover {
   color: #2e9dff; 
}
.navbar .logo {
    display: flex;
    align-items: center;
    transition: transform 0.3s ease;
}
.navbar .logo img {
    height: 66px;
    margin-right: 10px;
    transition: transform 0.3s ease; 
}
.navbar .logo p {
    font-size: 1.4em;
    margin: 0;
    color: #2e9dff;
    letter-spacing: 2px;
}
.navbar .logo:hover {
    transform: translateY(-3px);
}
.dropdown-btn {
    display: none;
    background-color: transparent;
    border: none;
    font-size: 1.5em;
    cursor: pointer;
    color: #6a859c;
}
h1,
p {
    margin-top: 3em;
    text-align: center;
    margin-left: 0;
    margin-right: 0;
    color: #2e9dff;
    font-size: 2.5em;
    transition: font-size 0.3s ease;
}
p {
    margin-top: 1em;
    font-size: 1.5em;
    color: #6a859c;
    transition: font-size 0.3s ease;
}
.color-block {
    margin-top: 7em;
    width: 100%;
    background-color: #edeff2;
    padding-top: 2em; 
    padding-bottom: 2em;
    box-sizing: border-box; 
}

.color-block h1 {
    margin-top: 0;
    color: #2e9dff; 
    font-size: 2em;
    text-align: center;
    transition: font-size 0.3s ease;
}
.color-block p {
    color: #6a859c; 
    font-size: 1em;
    text-align: center;
    margin-left: 15px;
    margin-right: 15px;
    transition: font-size 0.3s ease;
}
.introduce{
    text-align: center;
    margin: 1em auto 0; 
    max-width: 780px; 
    font-size: 0.7em;
    transition: font-size 0.3s ease;
}
.site-footer {
    width: 100%;
    height: 2.5em;
    background-color: #181818;
    color: white; 
    text-align: center; 
    padding: 0.5em 0;
    margin-top: 0; 
}




@media (max-width: 780px) {
    .nav-links {
        display: none;
        flex-direction: column;
        position: absolute;
        top: 100%;
        left: 0;
        width: 100%;
        background-color: #3b99d9;
        box-shadow: 0 7px 9px rgba(0, 0, 0, 0.5);
    }

    .nav-links a {
        text-align: left;
        padding-left: 2em;
        padding-top: 0.4em;
        padding-bottom: 0.4em;
        color: white; 
    }
    .nav-links a:hover {
        color: #0088ff;
    }

    .dropdown-btn {
        display: block;
    }
    .nav-links.show {
        display: flex;
    }
    h1{
        font-size: 1.8em;
    }
    p{
        font-size: 0.9em;
    }
    .color-block h1 {
        font-size: 1.8em;
    }
    .color-block p {
        font-size: 0.9em;
    }
}