* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: 'Segoe UI', Arial, sans-serif;
        }

        body {
            overflow-x: hidden;
        }

        #bouncing-ad {
            position: fixed;
            width: 120px;
            height: 120px;
            background: url(../images/cat2.gif);
            background-size: contain;
            border-radius: 10px;
            box-shadow: 0 0 15px rgba(0, 0, 0, 0.3);
            cursor: pointer;
            display: flex;
            align-items: center;
            justify-content: center;
            color: white;
            font-family: Arial;
            transition: transform 0.2s;
            color: red;
            font-size: small;
            z-index: 9999;
        }

        a {
            color: inherit;
            text-decoration: none;
            display: block;
        }

        header {
            background-color: #2c3e50;
            color: white;
            padding: 2rem 1.5rem;
            text-align: center;
            box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
        }

        nav.title {
            background-color: #3498db;
            padding: 1rem;
            position: sticky;
            z-index: 100;
            top: 0;
        }

        .titlelist {
            list-style: none;
            display: flex;
            justify-content: center;
        }

        .titlelist a {
            color: white;
            text-decoration: none;
            padding: 0.8rem 1.5rem;
            border-radius: 4px;
            transition: all 0.3s;
        }

        .subject {
            background: #f8f9fa;
            padding: 2rem 1rem;

        }

        div.imgs {
            z-index: 1;
            position: relative;
            height: 600px;
            width: 80%;
            margin: 0px auto 20px auto;
            border-radius: 5px 5px;
            background-image: url(../images/subject03.jpg);
            background-size: cover;
            background-repeat: no-repeat;
            background-position: center;
            transition: 0.5s;
        }

        div.imgs ul {
            list-style: none;
            height: 50px;
            width: 180px;
            position: absolute;
            right: 20px;
            bottom: 20px;
            display: flex;
            justify-content: space-around;
        }

        div.imgs ul li {
            display: inline-block;
            width: 50px;
            background-color: #ccc;
            border-radius: 50px;
            transition: 0.5s;
            cursor: pointer;
        }

        div.imgs ul li#focus {
            background-color: red;
        }

        .subjectcontain {

            display: flex;
            width: 80%;
            justify-content: space-between;
            gap: 20px;
            margin: 0 auto;
        }

        .card {
            position: relative;
            background: white;
            padding: 1.5rem;
            height: 100px;
            width: 230px;
            border-radius: 8px;
            text-align: center;
            box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
            transition: 0.5s;
            cursor: pointer;
            z-index: 2;
        }

        .card p {
            transition: 0.5s;
            opacity: 0;
            padding-top: 50px;
            position: absolute;
            height: 100%;
            width: 100%;
            left: 0px;
            bottom: 0px;
            background-color: rgba(0, 0, 0, 0.1);
            border-radius: 8px;
        }


        .card:hover {
            transform: translateY(-5px);
            background-color: rgba(0, 0, 0, 0.1);
        }

        #yuwen {
            border-top: 4px solid #e74c3c;
        }

        #shuxue {
            border-top: 4px solid #3498db;
        }

        #yingyu {
            border-top: 4px solid #2ecc71;
        }

        #wuli {
            border-top: 4px solid #9b59b6;
        }

        #huaxue {
            border-top: 4px solid #f1c40f;
        }

        .container {
            display: flex;
            flex-wrap: wrap;
            padding: 2rem;
            gap: 2rem;
            max-width: 1400px;
            margin: 0 auto;
        }

        .content {
            flex: 3;
            min-width: 300px;
        }

        /* 学科专区 */
        .subjectsection {
            margin: 3rem 0;
            padding: 2rem;
            background: white;
            border-radius: 8px;
            box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
        }


        .sidebar {
            text-align: left;
            height: 140px;
            width: 100px;
            position: fixed;
            left: 50px;
            bottom: 30px;
            background-color: #ccc;
            border-radius: 3px;
            padding-left: 10px;
            padding-right: 10px;
            z-index: 100;
        }

        .sidebar h3 {
            height: 40px;
            line-height: 40px;
        }

        .sidebar ul {
            list-style: none;
            display: flex;
            justify-content: space-around;
            flex-direction: column;
        }

        /* 页脚 */
        .footer {
            background-color: #34495e;
            color: white;
            padding: 2rem;
            text-align: center;
            margin-top: 1rem;

        }

        .footer p {
            line-height: 30px;
        }

        .footer p a {
            color: red;
            text-decoration: underline;
            font-size: 20px;
            font-weight: bolder;
        }