/* CSS Document */
  body {
            font-family: Arial, sans-serif;
            margin: 0;
            padding: 0;
            background-color: #000; /* 设置背景颜色 */
            color: white;
        }

        header {
            max-width: 90%;
            margin: auto;
            display: flex;
            justify-content: space-between;
            align-items: center;
            padding: 3rem 2rem;
            position: relative;
            z-index: 1000;
        }

        .logo {
            font-size: 1.5rem;
            font-weight: bold;
        }

        #mainNav ul {
            list-style-type: none;
            display: flex;
            gap: 1rem;
            margin: 0;
            padding: 0;
        }

        #mainNav li {
            position: relative;
        }

        #mainNav a {
            text-decoration: none;
            color: #fff;
            font-size: 1rem;
            transition: color 0.3s ease;
        }

        #mainNav a:hover {
            color: #007BFF;
        }

        .menu-btn {
            display: none;
            flex-direction: column;
            justify-content: space-around;
            width: 2rem;
            height: 2rem;
            background: transparent;
            border: none;
            cursor: pointer;
            padding: 0;
            box-sizing: border-box;
            transition: all 0.3s linear;
        }

        .menu-btn span {
            width: 2rem;
            height: 1px;
            background: #fff;
            border-radius: 0px;
            transition: all 0.3s cubic-bezier(0.645, 0.045, 0.355, 1);
            position: relative;
            transform-origin: 1px;
        }

        .menu-btn.active span:nth-child(1) {
            transform: rotate(45deg);
        }

        .menu-btn.active span:nth-child(2) {
            opacity: 0;
        }

        .menu-btn.active span:nth-child(3) {
            transform: rotate(-45deg);
        }

        .nav-menu {
            display: none;
            flex-direction: column;
            align-items: center;
            background-color: #fff;
            padding: 1rem;
            margin-top: 1rem;
            gap: 1rem;
            transition: all 0.3s ease-in-out;
            position: absolute;
            top: 100%;
            left: 0;
            right: 0;
            z-index: 999;
            box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
        }

        .nav-menu.active {
            display: flex;
        }

        .nav-menu a {
            text-decoration: none;
            color: black;
            font-size: 1.2rem;
        }

        footer {
            background-color: #000;
            color: white;
            text-align: center;
            padding: 1rem 0;
            bottom: 0;
            width: 100%;
        }