/* === V6 (QQ 风格) 基本样式与变量 === */
@import url('https://fonts.googleapis.com/css2?family=Poppins:wght@300;400;500;600;700&family=Noto+Sans+SC:wght@300;400;500;700&display=swap');

:root {
    /* V6 色彩方案 - QQ 蓝主调 + 浅灰背景 */
    --primary-color-v6: #0095ff; /* QQ 主蓝色 */
    --primary-light-v6: #66c2ff;
    --primary-dark-v6: #0077cc;
    --secondary-color-v6: #ffc107; /* 黄色作为少量点缀 (可选) */
    --accent-color-v6: #4caf50; /* 绿色用于成功状态 (可选) */
    --light-bg-v6: #ffffff;
    --medium-bg-v6: #f5f7fa; /* 非常浅的灰色背景 */
    --white-v6: #ffffff;
    --dark-text-v6: #333333; /* 深灰色文字 */
    --medium-text-v6: #666666; /* 中灰色文字 */
    --light-text-v6: #999999; /* 浅灰色文字 */
    --border-color-light-v6: #e8e8e8; /* 更浅的边框 */
    --border-color-medium-v6: #dddddd;
    --footer-bg-v6: #333333; /* 页脚深灰色 */
    --footer-text-v6: #cccccc;
    --footer-link-hover-v6: var(--primary-light-v6);

    /* V6 字体 */
    --font-primary-v6: 'Poppins', 'Noto Sans SC', sans-serif;
    --font-secondary-v6: 'Poppins', 'Noto Sans SC', sans-serif;

    /* V6 阴影 (非常微妙) */
    --shadow-sm-v6: 0 2px 8px rgba(0, 0, 0, 0.04);
    --shadow-md-v6: 0 4px 12px rgba(0, 0, 0, 0.06);
    --shadow-lg-v6: 0 8px 24px rgba(0, 0, 0, 0.08);
    --shadow-xl-v6: 0 16px 48px rgba(0, 0, 0, 0.1);

    /* V6 圆角 (适中) */
    --border-radius-base-v6: 6px;
    --border-radius-lg-v6: 10px;

    --transition-v6: all 0.3s ease;
}

/* === V6 重置与全局设置 === */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body.theme-v6 {
    font-family: var(--font-primary-v6);
    line-height: 1.7;
    color: var(--medium-text-v6);
    background-color: var(--light-bg-v6);
    opacity: 1;
    transition: none;
}

body.theme-v6.loaded {
    opacity: 1;
}

.container {
    width: 100%;
    max-width: 1180px; /* 调整容器宽度 */
    margin: 0 auto;
    padding: 0 1rem;
}

section {
    padding: 5rem 0;
    position: relative;
    overflow: hidden; /* 防止内容溢出 */
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

a {
    color: var(--primary-color-v6);
    text-decoration: none;
    transition: var(--transition-v6);
}

a:hover {
    color: var(--primary-dark-v6);
}

ul {
    list-style: none;
}

h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-secondary-v6);
    color: var(--dark-text-v6);
    line-height: 1.4;
    font-weight: 500; /* 默认字重调整 */
    letter-spacing: 0;
}

.section-header {
    text-align: center;
    margin-bottom: 3.5rem;
}

.section-header h2 {
    font-size: 2.1rem;
    margin-bottom: 0.8rem;
    font-weight: 600;
}

.section-header p {
    font-size: 1rem;
    color: var(--light-text-v6);
    max-width: 600px;
    margin: 0 auto;
}

/* === V6 按钮样式 (QQ 风格) === */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.7rem 1.9rem;
    border-radius: var(--border-radius-base-v6);
    font-weight: 400; /* 稍细字重 */
    font-size: 0.95rem;
    transition: var(--transition-v6);
    cursor: pointer;
    border: 1px solid transparent;
    text-transform: none;
    letter-spacing: 0.5px;
    position: relative;
    overflow: hidden;
}

.btn i {
    margin-left: 0.5rem;
    font-size: 0.9rem;
}

/* V6 主按钮 - QQ 蓝 */
.btn-primary {
    background-color: var(--primary-color-v6);
    color: white;
    border-color: var(--primary-color-v6);
    /* box-shadow: 0 2px 5px rgba(0, 149, 255, 0.2); */
}

.btn-primary:hover {
    background-color: var(--primary-dark-v6);
    border-color: var(--primary-dark-v6);
    transform: translateY(-1px);
    /* box-shadow: 0 4px 10px rgba(0, 149, 255, 0.25); */
}

/* V6 描边按钮 - 浅边框 */
.btn-outline {
    background: transparent;
    color: var(--primary-color-v6);
    border-color: var(--primary-light-v6);
}

.btn-outline:hover {
    background-color: rgba(0, 149, 255, 0.05); /* 极淡蓝色背景 */
    color: var(--primary-dark-v6);
    border-color: var(--primary-color-v6);
}

/* === V6 导航栏 (干净风格) === */
.header-v6 {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background-color: var(--white-v6);
    /* backdrop-filter: none; */
    z-index: 1000;
    padding: 0.9rem 0;
    transition: padding 0.3s ease, box-shadow 0.3s ease;
    border-bottom: 1px solid var(--border-color-light-v6);
    box-shadow: none;
}

.header-v6.scrolled {
    padding: 0.7rem 0;
    box-shadow: var(--shadow-sm-v6);
}

.header-v6 .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.header-v6 .logo {
    display: flex;
    align-items: center;
}

.header-v6 .logo h1 {
    font-size: 1.4rem;
    font-weight: 600;
    color: var(--dark-text-v6);
    margin-left: 0.7rem;
}

.header-v6 .logo-icon {
    width: 36px;
    height: 36px;
    background: var(--primary-color-v6);
    border-radius: var(--border-radius-base-v6);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 1.1rem;
    box-shadow: none;
}

.header-v6 .nav-links {
    display: flex;
    gap: 2rem;
}

.header-v6 .nav-links a {
    color: var(--medium-text-v6);
    font-weight: 400;
    position: relative;
    padding: 0.4rem 0;
    font-size: 0.9rem;
}

.header-v6 .nav-links a i {
    display: none;
}

.header-v6 .nav-links a:hover,
.header-v6 .nav-links a.active {
    color: var(--primary-color-v6);
}

/* V6 Nav Link Hover - 底部细线 */
.header-v6 .nav-links a::after {
    content: '';
    position: absolute;
    width: 0;
    height: 2px;
    background: var(--primary-color-v6);
    bottom: -6px;
    left: 50%;
    transform: translateX(-50%);
    transition: width 0.3s ease;
    border-radius: 1px;
}

.header-v6 .nav-links a:hover::after,
.header-v6 .nav-links a.active::after {
    width: 100%;
}

.header-v6 .mobile-menu {
    display: none;
    font-size: 1.4rem;
    cursor: pointer;
    color: var(--dark-text-v6);
}

/* === V6 英雄区域 (简洁干净) === */
.hero-v6 {
    padding: 8rem 0 7rem;
    background-color: var(--white-v6); /* 白色背景 */
    text-align: center;
    position: relative;
    /* 可以考虑在这里放一个大的插画或产品图占位 */
}

.hero-v6 .hero-content {
    max-width: 700px;
    margin: 0 auto;
    position: relative;
    z-index: 1;
}

.hero-v6 .hero-content h1 {
    font-size: 3.2rem;
    font-weight: 600;
    margin-bottom: 1.2rem;
    line-height: 1.3;
    color: var(--dark-text-v6);
}

/* 移除标题高亮 */
.hero-v6 .hero-content h1 .highlight { color: inherit; }

.hero-v6 .hero-content p {
    font-size: 1.05rem;
    margin-bottom: 2.2rem;
    color: var(--medium-text-v6);
    max-width: 550px;
    margin-left: auto;
    margin-right: auto;
}

.hero-v6 .hero-buttons {
    display: flex;
    justify-content: center;
    gap: 1rem;
}

/* === V6 关于我们 (图文混排) === */
.about-v6 {
    background-color: var(--medium-bg-v6); /* 浅灰背景 */
}

.about-v6 .about-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 3rem;
    align-items: center;
}

.about-v6 .about-image {
    border-radius: var(--border-radius-lg-v6);
    overflow: hidden;
    box-shadow: var(--shadow-md-v6);
    position: relative;
}

.about-v6 .about-text h3 {
    font-size: 1.8rem;
    margin-bottom: 1rem;
    color: var(--dark-text-v6);
    font-weight: 600;
}

.about-v6 .about-text p {
    margin-bottom: 1.2rem;
    font-size: 0.95rem;
    color: var(--medium-text-v6);
}

/* V6 Stats - 简洁列表 */
.about-v6 .about-stats {
    display: flex; /* 横向排列 */
    flex-wrap: wrap;
    gap: 1.5rem;
    margin-top: 1.5rem;
    background-color: transparent;
    padding: 0;
    border: none;
}

.about-v6 .stat-item {
    text-align: left;
    padding: 0;
    border: none;
    background-color: transparent;
    border-radius: 0;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.about-v6 .stat-number {
    font-size: 1.8rem;
    font-weight: 600;
    color: var(--primary-color-v6);
    margin-bottom: 0;
    line-height: 1;
}

.about-v6 .stat-text {
    font-size: 0.9rem;
    color: var(--medium-text-v6);
    font-weight: 400;
    line-height: 1.2;
}

/* === V6 产品展示 (卡片式) === */
.products-v6 {
    background-color: var(--white-v6);
}

.products-v6 .product-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(270px, 1fr));
    gap: 2rem;
}

.products-v6 .product-card {
    background: var(--white-v6);
    border-radius: var(--border-radius-lg-v6);
    overflow: hidden;
    box-shadow: var(--shadow-sm-v6);
    transition: var(--transition-v6);
    border: 1px solid var(--border-color-light-v6);
    height: 100%;
    display: flex;
    flex-direction: column;
    position: relative;
    z-index: 1;
}

/* V6 卡片悬停 - 阴影加深 */
.products-v6 .product-card:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-md-v6);
    border-color: var(--border-color-light-v6);
}

.products-v6 .product-image {
    height: 190px;
    overflow: hidden;
    position: relative;
    background-color: var(--medium-bg-v6); /* 图片背景色 */
}

.products-v6 .product-image img {
    /* 可能需要 object-fit: cover; */
}

.products-v6 .product-info {
    padding: 1.3rem;
    flex-grow: 1;
    display: flex;
    flex-direction: column;
}

.products-v6 .product-info h3 {
    font-size: 1.1rem;
    margin-bottom: 0.6rem;
    font-weight: 500;
    color: var(--dark-text-v6);
}

.products-v6 .product-info p {
    color: var(--medium-text-v6);
    font-size: 0.9rem;
    margin-bottom: 1rem;
    flex-grow: 1;
}

.products-v6 .product-link {
    color: var(--primary-color-v6);
    font-weight: 400;
    font-size: 0.9rem;
    display: inline-flex;
    align-items: center;
    gap: 0.3rem;
    margin-top: auto;
}
.products-v6 .product-link:hover {
    color: var(--primary-dark-v6);
    text-decoration: underline;
}
.products-v6 .product-link i {
    font-size: 0.8rem;
    transition: transform 0.3s ease;
}
.products-v6 .product-link:hover i {
    transform: translateX(3px);
    /* color: var(--accent-color-v5); 移除箭头变色 */
}

/* === V6 服务项目 (图标列表) === */
.services-v6 {
    background-color: var(--medium-bg-v6);
}

.services-v6 .services-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1rem 2rem; /* 调整间距 */
}

.services-v6 .service-card {
    background: transparent;
    border-radius: 0;
    padding: 1.5rem 0.5rem;
    text-align: left;
    box-shadow: none;
    transition: none;
    border: none;
    display: flex;
    align-items: flex-start;
    position: relative;
    overflow: visible;
    z-index: 1;
    gap: 1rem;
}

/* 移除服务卡片悬停效果 */
.services-v6 .service-card:hover {
    transform: none;
    box-shadow: none;
    border-color: transparent;
    background-color: transparent;
}

.services-v6 .service-icon {
    width: 42px;
    height: 42px;
    background: transparent;
    /* background: var(--primary-light-v6); */
    border-radius: 50%; /* 圆形图标 */
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    color: var(--primary-color-v6); /* 主色图标 */
    transition: var(--transition-v6);
    margin-bottom: 0;
    box-shadow: none;
    flex-shrink: 0;
    text-align: center;
}

.services-v6 .service-card:hover .service-icon {
    /* transform: scale(1.1); */
    color: var(--primary-dark-v6);
}

.services-v6 .service-card .service-text-content {
    padding-top: 0.2rem; /* 微调文本对齐 */
}

.services-v6 .service-card h3 {
    font-size: 1.1rem;
    margin-bottom: 0.4rem;
    font-weight: 500;
    color: var(--dark-text-v6);
}

.services-v6 .service-card p {
    color: var(--medium-text-v6);
    font-size: 0.9rem;
    line-height: 1.6;
}

/* === V6 新闻动态 (简洁列表感) === */
.news-v6 {
    background-color: var(--white-v6);
}

.news-v6 .news-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2.5rem;
}

.news-v6 .news-card {
    background-color: var(--white-v6);
    border-radius: var(--border-radius-base-v6); /* 基础圆角 */
    overflow: hidden;
    box-shadow: none; /* 移除阴影 */
    transition: var(--transition-v6);
    border: 1px solid var(--border-color-light-v6);
    height: 100%;
    display: flex;
    flex-direction: column;
}

.news-v6 .news-card:hover {
    transform: none;
    box-shadow: var(--shadow-sm-v6); /* 悬停加阴影 */
    border-color: var(--border-color-medium-v6);
}

.news-v6 .news-image {
    height: 170px;
    overflow: hidden;
    position: relative;
    background-color: var(--medium-bg-v6);
}

.news-v6 .news-content {
    padding: 1.2rem;
    flex-grow: 1;
    display: flex;
    flex-direction: column;
}

.news-v6 .news-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 0.8rem;
    margin-bottom: 0.6rem;
    color: var(--light-text-v6);
}

.news-v6 .news-date {
    display: flex;
    align-items: center;
    gap: 0.3rem;
}

.news-v6 .news-category {
    background-color: transparent;
    color: var(--light-text-v6);
    padding: 0;
    font-weight: 400;
    border-radius: 0;
    font-size: 0.8rem;
    border: 1px solid var(--border-color-light-v6);
    padding: 2px 6px;
    border-radius: 4px;
}

.news-v6 .news-title {
    font-size: 1.05rem;
    font-weight: 500;
    margin-bottom: 0.6rem;
    line-height: 1.4;
}

.news-v6 .news-title a {
    color: var(--dark-text-v6);
    transition: var(--transition-v6);
}

.news-v6 .news-title a:hover {
    color: var(--primary-color-v6);
}

.news-v6 .news-excerpt {
    font-size: 0.9rem;
    color: var(--medium-text-v6);
    margin-bottom: 1rem;
    line-height: 1.6;
    display: -webkit-box;
    -webkit-line-clamp: 2; /* 最多显示两行 */
    -webkit-box-orient: vertical;
    overflow: hidden;
    flex-grow: 1;
}

.news-v6 .news-readmore {
    color: var(--light-text-v6); /* 默认浅色 */
    font-size: 0.85rem;
    font-weight: 400;
    display: inline-flex;
    align-items: center;
    gap: 0.3rem;
    margin-top: auto;
}

.news-v6 .news-readmore:hover {
    color: var(--primary-color-v6);
    text-decoration: none;
}

.news-v6 .news-readmore:hover i {
    transform: translateX(3px);
    color: var(--primary-color-v6);
}

/* === V6 联系我们 (表单中心) === */
.contact-v6 {
    background-color: var(--medium-bg-v6);
    padding-bottom: 6rem;
}

.contact-v6 .contact-content {
    display: grid;
    grid-template-columns: 1fr; /* 单列布局 */
    gap: 3rem;
    max-width: 700px; /* 限制最大宽度 */
    margin: 0 auto; /* 居中 */
}

.contact-v6 .contact-form {
    background: var(--white-v6); /* 白色背景 */
    border-radius: var(--border-radius-lg-v6);
    padding: 2.5rem;
    box-shadow: var(--shadow-md-v6);
    border: 1px solid var(--border-color-light-v6);
    position: relative;
    z-index: 1;
    overflow: hidden;
}

.contact-v6 .form-group {
    margin-bottom: 1.3rem;
    position: relative;
}

.contact-v6 .form-label {
    display: block;
    margin-bottom: 0.4rem;
    font-size: 0.9rem;
    font-weight: 400;
    color: var(--medium-text-v6);
}

.contact-v6 .form-group input,
.contact-v6 .form-group textarea {
    width: 100%;
    padding: 0.75rem 0.9rem;
    border: 1px solid var(--border-color-medium-v6);
    border-radius: var(--border-radius-base-v6);
    font-family: inherit;
    font-size: 0.95rem;
    transition: var(--transition-v6);
    background-color: var(--white-v6);
    color: var(--dark-text-v6);
}

.contact-v6 .form-group input::placeholder,
.contact-v6 .form-group textarea::placeholder {
    color: var(--light-text-v6);
    opacity: 0.8;
}

.contact-v6 .form-group input:focus,
.contact-v6 .form-group textarea:focus {
    outline: none;
    border-color: var(--primary-color-v6);
    box-shadow: 0 0 0 3px rgba(0, 149, 255, 0.15);
}

.contact-v6 .form-group textarea {
    height: 100px;
    resize: vertical;
}

/* 联系信息调整为表单下方 */
.contact-v6 .contact-info {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); /* 多列显示 */
    gap: 1.5rem;
    margin-top: 2.5rem; /* 与表单间距 */
    text-align: center;
}

.contact-v6 .info-item {
    background: transparent;
    border-radius: 0;
    padding: 0.5rem;
    box-shadow: none;
    border: none;
    transition: none;
    position: relative;
    overflow: visible;
    z-index: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.5rem;
}

.contact-v6 .info-icon {
    width: 40px;
    height: 40px;
    background: transparent;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.4rem;
    color: var(--primary-color-v6);
    margin-bottom: 0.3rem;
    box-shadow: none;
    transition: var(--transition-v6);
    flex-shrink: 0;
}

.contact-v6 .info-item h3 {
    font-size: 1rem;
    margin-bottom: 0.3rem;
    color: var(--dark-text-v6);
    font-weight: 500;
}

.contact-v6 .info-item p {
    color: var(--medium-text-v6);
    margin-bottom: 0.1rem;
    font-size: 0.9rem;
    display: block; /* 换行显示 */
    line-height: 1.5;
}

.contact-v6 .info-item p i {
    display: none; /* 隐藏文本前的图标 */
}

/* === V6 友情链接 (更低调) === */
.friend-links-v6 {
    background-color: var(--white-v6);
    padding: 2.5rem 0;
    border-top: 1px solid var(--border-color-light-v6);
}

.friend-links-v6 .section-header {
    margin-bottom: 2rem;
}
.friend-links-v6 .section-header h2 {
    font-size: 1.5rem; /* 减小标题 */
    font-weight: 500;
}
.friend-links-v6 .section-header p {
    display: none; /* 隐藏描述 */
}

.friend-links-v6 .links-grid {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 1rem 1.5rem;
    max-width: 1000px;
    margin: 0 auto;
}

.friend-links-v6 .links-grid a {
    color: var(--medium-text-v6);
    font-size: 0.9rem;
    padding: 0; /* 移除内边距 */
    border-radius: 0;
    transition: var(--transition-v6);
    background-color: transparent;
    border: none; /* 移除边框 */
}

.friend-links-v6 .links-grid a:hover {
    color: var(--primary-color-v6);
    background-color: transparent;
    border-color: transparent;
    box-shadow: none;
    transform: none;
}

/* === V6 页脚 (灰调简洁) === */
.footer-v6 {
    background-color: var(--footer-bg-v6);
    color: var(--footer-text-v6);
    padding: 4rem 0 1.5rem;
    position: relative;
    overflow: hidden;
}

.footer-v6 .footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr)); /* 自适应列 */
    gap: 2rem;
    margin-bottom: 2.5rem;
    position: relative;
    z-index: 1;
}

.footer-v6 .footer-content h3 {
    font-size: 1rem;
    margin-bottom: 0.8rem;
    color: var(--white-v6);
    position: relative;
    padding-bottom: 0.4rem;
    font-weight: 500;
    border-bottom: 1px solid #555; /* 页脚分隔线 */
}

.footer-v6 .footer-about p {
    color: var(--footer-text-v6);
    font-size: 0.85rem;
    line-height: 1.6;
    margin-bottom: 1rem;
    opacity: 0.7;
}

.footer-v6 .social-icons {
    display: flex;
    gap: 1rem;
    margin-top: 1rem;
}

.footer-v6 .social-icons a {
    width: 32px;
    height: 32px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 50%; /* 圆形图标 */
    display: flex;
    align-items: center;
    justify-content: center;
    color: #aaa;
    transition: var(--transition-v6);
    font-size: 0.9rem;
}

.footer-v6 .social-icons a:hover {
    color: var(--white-v6);
    background-color: var(--primary-color-v6);
}

.footer-v6 .footer-links ul li {
    margin-bottom: 0.4rem;
}

.footer-v6 .footer-links a {
    color: var(--footer-text-v6);
    transition: var(--transition-v6);
    display: inline-flex;
    align-items: center;
    font-size: 0.85rem;
    opacity: 0.7;
}

.footer-v6 .footer-links a:hover {
    color: var(--footer-link-hover-v6);
    opacity: 1;
    text-decoration: underline;
}

.footer-v6 .footer-contact p {
    color: var(--footer-text-v6);
    margin-bottom: 0.5rem;
    display: flex;
    align-items: flex-start;
    gap: 0.5rem;
    font-size: 0.85rem;
    opacity: 0.7;
}

.footer-v6 .footer-contact i {
    color: #888;
    margin-top: 0.2em;
    width: 14px;
    text-align: center;
    flex-shrink: 0;
    opacity: 0.7;
}

.footer-v6 .footer-bottom {
    border-top: 1px solid #444; /* 页脚底部分隔线 */
    padding-top: 1.5rem;
    text-align: center;
    color: #888;
    font-size: 0.8rem;
}

.footer-v6 .footer-bottom a {
    color: #aaa;
    font-weight: 400;
}
.footer-v6 .footer-bottom a:hover {
    color: var(--primary-light-v6);
}

/* === V6 回到顶部按钮 (匹配 QQ 风格) === */
.scroll-top-btn {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    width: 42px;
    height: 42px;
    border-radius: 50%; /* 圆形 */
    background: var(--white-v6);
    color: var(--primary-color-v6);
    border: 1px solid var(--border-color-light-v6);
    font-size: 1.1rem;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    z-index: 99;
    opacity: 0;
    visibility: hidden;
    transform: translateY(15px);
    transition: all 0.3s ease-out;
    box-shadow: var(--shadow-md-v6);
}

.scroll-top-btn.visible {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.scroll-top-btn:hover {
    background-color: var(--medium-bg-v6);
    color: var(--primary-dark-v6);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg-v6);
}

/* === V6 响应式调整 === */
@media (max-width: 992px) {
    .header-v6 .nav-links { display: none; }
    .header-v6 .mobile-menu { display: block; }
    .about-v6 .about-content {
        grid-template-columns: 1fr;
        gap: 2.5rem;
    }
    .about-v6 .about-text {
        order: -1;
    }
    .contact-v6 .contact-content {
        /* grid-template-columns: 1fr; */
        /* gap: 2.5rem; */
    }
    .footer-v6 .footer-content {
        grid-template-columns: repeat(2, 1fr);
        gap: 2rem;
    }
}

@media (max-width: 768px) {
    /* Mobile Nav Styles - V6 */
    .nav-links {
        position: fixed;
        top: 0;
        right: -100%;
        width: 80%;
        max-width: 280px;
        height: 100vh;
        flex-direction: column;
        align-items: stretch; /* 链接撑满宽度 */
        justify-content: flex-start;
        background: var(--white-v6);
        padding: 5rem 0 2rem;
        box-shadow: -5px 0 15px rgba(0, 0, 0, 0.08);
        transition: right 0.35s cubic-bezier(0.4, 0, 0.2, 1);
        z-index: 1001;
        gap: 0;
        border-left: 1px solid var(--border-color-light-v6);
    }
    .nav-links.active {
        right: 0;
    }
    .nav-links li {
        margin: 0;
        width: 100%;
    }
    .nav-links a {
        display: flex;
        align-items: center;
        padding: 0.9rem 1.5rem;
        font-size: 1rem;
        color: var(--dark-text-v6);
        font-weight: 400;
        border-bottom: 1px solid var(--border-color-light-v6);
        width: 100%;
        border-radius: 0;
    }
    .nav-links a i {
        display: inline-block;
        margin-right: 1rem;
        width: 20px;
        text-align: center;
        color: var(--primary-color-v6);
        font-size: 1rem;
    }
    .nav-links a.active, .nav-links a:hover {
        color: var(--primary-color-v6);
        background-color: var(--medium-bg-v6);
    }
    .nav-links a::after { display: none; }

    .overlay {
        background: rgba(0, 0, 0, 0.3); /* 更浅遮罩 */
        /* ... rest of overlay styles */
    }
    .overlay.active {
        opacity: 1;
        visibility: visible;
    }

    .hero-v6 .hero-content h1 {
        font-size: 2.5rem;
    }
    .hero-v6 .hero-content p {
        font-size: 1rem;
    }
    .section-header h2 {
        font-size: 1.9rem;
    }
    .services-v6 .service-card {
        padding: 1rem 0.5rem;
        gap: 0.8rem;
        /* flex-direction: column; */
        /* align-items: center; */
        /* text-align: center; */
    }
    .services-v6 .service-icon {
        width: 38px;
        height: 38px;
        font-size: 1.3rem;
    }
    .contact-v6 .contact-info {
        grid-template-columns: 1fr; /* 移动端单列 */
        text-align: left;
        align-items: flex-start;
    }
    .contact-v6 .info-item {
        flex-direction: row; /* 图标和文字同行 */
        align-items: center;
        gap: 1rem;
        text-align: left;
    }
}

@media (max-width: 576px) {
    section {
        padding: 4rem 0;
    }
    .container {
        padding: 0 1rem;
    }
    .hero-v6 .hero-content h1 {
        font-size: 2.1rem;
    }
    .hero-v6 .hero-content p {
        font-size: 0.95rem;
        margin-bottom: 1.8rem;
    }
    .hero-v6 .hero-buttons {
        flex-direction: column;
        gap: 0.8rem;
    }
    .hero-v6 .hero-buttons .btn {
        width: 100%;
        max-width: 260px;
        margin: 0 auto;
        padding: 0.7rem 1.5rem;
    }
    .about-v6 .about-stats {
        flex-direction: column; /* 竖排 */
        align-items: flex-start;
        gap: 1rem;
    }
    .footer-v6 .footer-content {
        grid-template-columns: 1fr;
        gap: 1.8rem;
        text-align: center;
    }
    .footer-v6 .footer-content h3 {
        border-bottom: 1px solid #555;
        padding-bottom: 0.4rem;
        margin-bottom: 0.6rem;
        text-align: center;
    }
    .footer-v6 .footer-content h3::after { display: none; }

    .footer-v6 .footer-about .social-icons {
        justify-content: center;
    }
    .footer-v6 .footer-links ul {
        padding-left: 0;
    }
    .footer-v6 .footer-contact p {
        justify-content: center;
        text-align: center;
    }
    .footer-v6 .footer-bottom {
        font-size: 0.75rem;
        padding-top: 1.5rem;
    }
    .contact-v6 .contact-form {
        padding: 2rem 1.5rem;
    }
}


/* === V6 自定义滚动条 === */
::-webkit-scrollbar {
    width: 6px; /* 最细 */
}

::-webkit-scrollbar-track {
    background: var(--medium-bg-v6);
}

::-webkit-scrollbar-thumb {
    background: var(--border-color-medium-v6);
    border-radius: 3px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--light-text-v6);
}