<style>
    :root {
        --primary: #2B6695;
        --background: #fafafa;
        --accent: #ff5722;
        --shadow: rgba(0, 0, 0, 0.3);
    }
    body {
        font-family: "Helvetica Neue", Arial, sans-serif;
        color: var(--primary);
        margin: 0;
        padding: 0;
        background-image: url('https://api.gumengya.com/Api/FjImg?format=image&appkey=253d812cbfbb77c03b910f9897e9487d');
        background-size: cover;
        background-attachment: fixed;
        background-position: center;
    }
    .footer {
        display: none;
    }
    header {
        margin: 20px;
        padding: 15px;
        border-radius: 15px;
        background-color: rgba(255, 255, 255, 0.5);
        box-shadow: 0 4px 6px var(--shadow);
    }
    #announcement {
        margin: 20px auto;
        padding: 15px;
        background-color: rgba(87, 229, 137, 0.6);
        color: #fff;
        text-align: center;
        font-size: 1.2em;
        border-radius: 15px;
        box-shadow: 0 4px 6px rgba(0, 0, 0, 0.3);
    }
    footer {
        position: fixed;
        bottom: 0;
        width: 100%;
        text-align: center;
        background-color: rgba(255, 255, 255, 0.5);
        border-radius: 15px;
        padding: 20px;
        box-shadow: 0 -4px 6px rgba(0, 0, 0, 0.3);
    }
    #back-to-top {
        font-weight: bold;
        text-decoration: underline;
    }
    #back-to-top:hover {
        color: var(--primary);
        text-decoration: none;
    }
    #leftcontent {
        display: none;
    }
    #banner {
        display: none;
    }
        #centercontent {
        margin: 20px auto;
        padding: 20px;
        max-width: 800px;
        background-color: rgba(255, 255, 255, 0.9);
        border-radius: 20px;
        box-shadow: 0 4px 10px rgba(0, 0, 0, 0.2);
        font-family: "Helvetica Neue", Arial, sans-serif;
        color: #333;
        text-align: left;
        line-height: 1.6;
        border-left: 5px solid #405de6; /* 左侧蓝色边框 */
    }

        #centercontent {
        margin: 20px auto;
        padding: 20px;
        max-width: 800px;
        background-color: rgba(240, 248, 255, 0.9); /* 浅蓝色背景 */
        border-radius: 20px;
        box-shadow: 0 4px 10px rgba(0, 0, 0, 0.1);
        font-family: "Helvetica Neue", Arial, sans-serif;
        color: #333;
        text-align: left;
        line-height: 1.6;
        border-left: 5px solid #b3e5fc; /* 浅蓝色边框 */
    }

    #centercontent h1, #centercontent h2 {
        color: #81c784; /* 浅绿色 */
    }

    #centercontent a {
        color: #fff176; /* 浅黄色 */
        text-decoration: none;
    }

    #centercontent a:hover {
        text-decoration: underline;
    }
</style>