.sub-navbar {
            display: flex;
            justify-content: center;
            background-color: white;
            padding: 10px 0;
            margin-top: 5%;
        }
        .subnav-links {
            list-style: none;
            padding: 0;
            margin: 0;
            display: flex;
            gap: 270px;
        }
        .subnav-links a {
            text-decoration: none;
            color: black;
            font-size: 1.2rem;
            font-family: 'Montserrat', sans-serif;
            font-weight: 500;
            transition: color 0.3s ease;
            border-radius: 5px;
        }
        .subnav-links a:hover {
            font-weight: bolder;
            border-bottom: rgb(87, 128, 216) 3px solid;
        }

        .subnav-links a.active {
            font-weight: bolder;
            border-bottom: rgb(87, 128, 216) 3px solid;
        }

        .subnav-links a:not(:last-child)::after {
            content: "|";
            color: black !important;
            font-weight: normal !important;
            position: absolute;
            margin-left: 125px; /* 250px的一半 */
        }

        .sub-navbar.fixed {
            position: fixed;
            margin-top: 4.5%;
            top: 0;
            left: 0;
            width: 100%;
            z-index: 1000;
            animation: slideDown 0.3s ease-out;
        }

        .hint-container {
            display: flex;
            justify-content: center;
            align-items: center;
            margin-bottom: 20px;
        }
        .hint-container img {
            max-width: 20px;
            height: auto;
            margin: 0 10px;
        }
        .hint-container p {
            font-weight: bold;
            font-size: 1.8rem;
            color: #333;
        }