* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: Arial, sans-serif;
    line-height: 1.6;
    color: #333;
    background: linear-gradient(to bottom, #f0f2f5, #ffffff);
    opacity: 0;
    transition: opacity 1s ease-in-out;
}
body.loaded {
    opacity: 1;
}

.navbar {
    display: flex;
    justify-content: space-between;
    padding: 20px;
    background-color: #fff;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
    position: sticky;
    top: 0;
    z-index: 10;
    transition: padding 0.3s ease;
}
.navbar.scrolled {
    padding: 10px;
}

.navbar a {
    margin-right: 20px;
    text-decoration: none;
    color: #333;
    font-weight: bold;
}

.cta-button {
    padding: 12px 24px;
    background-color: #ff9900;
    color: white;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-weight: bold;
    transition: background-color 0.3s ease, transform 0.1s ease;
}
.cta-button:hover {
    background-color: #e68a00;
}
.cta-button.clicked {
    transform: scale(0.95);
}

#hero {
    text-align: center;
    padding: 100px 20px;
    background: linear-gradient(135deg, #6a11cb, #2575fc);
    color: white;
}


#back-to-top {
    position: fixed;
    bottom: 20px;
    right: 20px;
    padding: 10px 20px;
    background-color: #ff9900;
    color: white;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    transition: opacity 0.3s ease;
}
#back-to-top:hover {
    opacity: 0.8;
}

.fade-in {
    opacity: 0;
    transition: opacity 0.8s ease-in-out;
}
.fade-in.visible {
    opacity: 1;
}

/* Responsive design omitted for brevity */

/* Responsive design omitted for brevity */

/* 大屏幕（桌面设备，宽度 >= 1200px） */
@media (min-width: 1200px) {
    /* 保持多列布局，最大化利用宽屏空间 */
    .benefits, .testimonials {
        flex-direction: row;
        justify-content: space-around;
    }

    .benefit, .testimonial {
        width: 30%; /* 每行展示3列 */
    }

    .navbar a {
        font-size: 1em; /* 适度增大字体，保证清晰 */
    }

    .cta-button {
        padding: 14px 28px; /* 加大按钮，增强视觉效果 */
    }
}

/* 中屏幕（平板设备，宽度 768px - 1199px） */
@media (min-width: 768px) and (max-width: 1199px) {
    /* 改为两列布局，适应较小的屏幕宽度 */
    .benefits, .testimonials {
        flex-direction: row;
        flex-wrap: wrap;
        justify-content: space-around;
    }

    .benefit, .testimonial {
        width: 45%; /* 每行展示2列 */
        margin-bottom: 20px;
    }

    .navbar a {
        font-size: 0.9em; /* 缩小字体，节省空间 */
    }

    .cta-button {
        padding: 12px 24px; /* 调整按钮大小 */
    }

    #hero h1 {
        font-size: 2em; /* 缩小标题 */
    }

    #hero p {
        font-size: 1em; /* 缩小副标题 */
    }
}

/* 小屏幕（手机设备，宽度 <= 767px） */
@media (max-width: 767px) {
    /* 切换为单列布局，适合小屏幕的垂直排列 */
    .navbar {
        flex-direction: column;
        align-items: center;
    }

    .navbar a {
        margin-bottom: 10px;
        font-size: 0.9em; /* 缩小字体 */
    }

    .benefits, .testimonials {
        flex-direction: column;
        align-items: center;
    }

    .benefit, .testimonial {
        width: 90%; /* 每行展示1列 */
        margin-bottom: 20px;
    }

    .cta-button {
        font-size: 0.9em;
        padding: 10px 20px; /* 缩小按钮 */
    }

    #hero h1 {
        font-size: 1.8em; /* 更小的标题适应屏幕 */
    }

    #hero p {
        font-size: 0.9em; /* 缩小副标题 */
    }

    .video-placeholder {
        height: 200px; /* 减小视频占位符高度 */
    }
}

/* 超小屏幕（超小设备，宽度 <= 576px） */
@media (max-width: 576px) {
    /* 保证布局清晰简洁，进一步缩小字体和按钮 */
    .navbar {
        padding: 10px;
    }

    .navbar a {
        font-size: 0.8em;
    }

    .benefit, .testimonial {
        width: 100%;
        padding: 15px;
    }

    #hero h1 {
        font-size: 1.6em;
    }

    #hero p {
        font-size: 0.8em;
    }

    .cta-button {
        font-size: 0.85em;
        padding: 8px 16px;
    }

    footer p {
        font-size: 0.8em; /* 更小的页脚文字 */
    }
}

/* 汉堡菜单样式 */
.hamburger-icon {
    display: none;
    flex-direction: column;
    cursor: pointer;
    margin-left: auto;
}

.hamburger-icon span {
    width: 25px;
    height: 3px;
    background-color: #333;
    margin: 4px 0;
}

/* 隐藏移动菜单 */
.mobile-menu {
    display: none;
    flex-direction: column;
    position: absolute;
    top: 60px; /* 根据导航栏高度调整 */
    right: 0;
    background-color: #fff;
    width: 100%;
    box-shadow: 0px 4px 8px rgba(0, 0, 0, 0.1);
    z-index: 100;
}

/* 在小屏幕上显示汉堡菜单 */
@media (max-width: 767px) {
    .navbar a, .navbar .cta-button {
        display: none; /* 隐藏导航栏链接和按钮 */
    }

    .hamburger-icon {
        display: flex;
    }

    .mobile-menu a, .mobile-menu .cta-button {
        padding: 15px;
        text-align: center;
        border-top: 1px solid #f0f0f0;
    }
}

/* Footer 样式优化 */
footer {
    background-color: #333;
    color: white;
    padding: 20px;
    text-align: center;
    border-top: 3px solid #ff9900;
}

.footer-content {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.footer-links {
    margin-top: 10px;
}

.footer-links a {
    color: #ff9900;
    text-decoration: none;
    margin: 0 8px;
    font-weight: bold;
}

.footer-links a:hover {
    text-decoration: underline;
}

@media (min-width: 768px) {
    .footer-content {
        flex-direction: row;
        justify-content: space-between;
    }
    .footer-links {
        margin-top: 0;
    }
}

/* 确保 .mobile-menu 在小屏幕时固定在顶部 */
.mobile-menu {
    position: fixed;
    top: 0;
    right: 0;
    width: 100%;
    display: none;
    flex-direction: column;
    background-color: #fff;
    box-shadow: 0px 4px 8px rgba(0, 0, 0, 0.1);
    z-index: 1000; /* 保证在最上层 */
}

/* 大屏幕强制隐藏 .mobile-menu */
@media (min-width: 768px) {
    .mobile-menu {
        display: none !important;
    }
}