/* ========================================================
   扁平化设计系统 - 多域名70%差异化
   ========================================================*/

/* CSS变量 - 通过PHP动态输出 */
:root {
    /* 颜色系统 - 默认值，会被PHP覆盖 */
    --primary: #0066cc;
    --secondary: #0052a3;
    --accent: #ff9500;

    /* 背景色 */
    --bg-main: #f5f8fc;
    --bg-card: #ffffff;
    --bg-section: #ffffff;
    --bg-input: #ffffff;

    /* 文字色 */
    --text-main: #1a1a2e;
    --text-sub: #64748b;
    --text-light: #9ca3af;

    /* 边框色 */
    --border: #e2e8f0;
    --border-light: #f1f5f9;

    /* 圆角 */
    --radius: 6px;
    --radius-lg: 12px;
    --radius-full: 9999px;

    /* 阴影 */
    --shadow: 0 2px 8px rgba(0,0,0,0.06);
    --shadow-hover: 0 4px 12px rgba(0,0,0,0.1);
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.04);

    /* 字体 */
    --font: 'PingFang SC', 'Microsoft YaHei', sans-serif;

    /* 尺寸 */
    --container-width: 1100px;
    --header-height: 64px;
    --spacing-sm: 12px;
    --spacing-md: 20px;
    --spacing-lg: 40px;

    /* 过渡 */
    --transition: all 0.2s ease;
}

/* ========================================================
   顶部悬浮Banner广告位
   ========================================================*/
.top-banner-ad {
    position: sticky;
    top: calc(var(--header-height) - 5px);
    left: 0;
    right: 0;
    z-index: 200;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    box-shadow: 0 4px 12px rgba(0,0,0,0.15);
    margin-bottom: var(--spacing-md);
    border-radius: 0 0 8px 8px;
}

.banner-ad-content {
    text-align: center;
    padding: var(--spacing-sm) var(--spacing-md);
}

.banner-ad-link {
    display: block;
    color: #fff;
    font-size: 15px;
    font-weight: 500;
    text-decoration: none;
}

.banner-ad-link:hover {
    text-decoration: underline;
}

.banner-ad-close {
    position: absolute;
    right: 12px;
    top: 50%;
    transform: translateY(-50%);
    background: rgba(255,255,255,0.2);
    border: none;
    color: #fff;
    font-size: 18px;
    cursor: pointer;
    width: 28px;
    height: 28px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
}

.banner-ad-close:hover {
    background: rgba(255,255,255,0.4);
}

/* ========================================================
   侧栏悬浮广告位
   ========================================================*/
.sidebar-sticky-ad {
    position: sticky;
    top: calc(var(--header-height) + 10px);
    z-index: 99;
    margin-bottom: var(--spacing-md);
}

.sidebar-ad-content {
    background: linear-gradient(135deg, #ff9500 0%, #ff7b00 100%);
    border-radius: var(--radius-lg);
    overflow: hidden;
    position: relative;
}

.sidebar-ad-link {
    display: block;
    text-decoration: none;
    color: #fff;
    padding: var(--spacing-md);
    text-align: center;
}

.sidebar-ad-badge {
    background: rgba(0,0,0,0.15);
    color: #d0d0d0;
    font-size: 11px;
    padding: 3px 8px;
    border-radius: 4px;
    display: inline-block;
    position: absolute;
    bottom: 8px;
    right: 8px;
    margin: 0;
}

.sidebar-ad-text {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 4px;
}

.sidebar-ad-desc {
    font-size: 13px;
    opacity: 0.9;
}

.sidebar-ad-close {
    position: absolute;
    right: 8px;
    top: 8px;
    background: rgba(255,255,255,0.2);
    border: none;
    color: #fff;
    font-size: 16px;
    cursor: pointer;
    width: 24px;
    height: 24px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
}

.sidebar-ad-close:hover {
    background: rgba(255,255,255,0.4);
}

/* ========================================================
   右下角广告位
   ========================================================*/
.bottom-right-ad {
    position: fixed;
    bottom: 20px;
    right: 20px;
    z-index: 1000;
    background: linear-gradient(135deg, #ff9500 0%, #ff7b00 100%);
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: 0 4px 12px rgba(0,0,0,0.15);
    max-width: 280px;
}

.bottom-right-ad-content {
    padding: var(--spacing-md);
    text-align: center;
    position: relative;
}

.bottom-right-ad-badge {
    background: rgba(0,0,0,0.15);
    color: #d0d0d0;
    font-size: 11px;
    padding: 3px 8px;
    border-radius: 4px;
    display: inline-block;
    position: absolute;
    bottom: 8px;
    right: 8px;
    margin: 0;
}

.bottom-right-ad-link {
    display: block;
    text-decoration: none;
    color: #fff;
    font-size: 14px;
    font-weight: 500;
}

.bottom-right-ad-close {
    position: absolute;
    right: 8px;
    top: 8px;
    background: rgba(255,255,255,0.2);
    border: none;
    color: #fff;
    font-size: 16px;
    cursor: pointer;
    width: 24px;
    height: 24px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
}

.bottom-right-ad-close:hover {
    background: rgba(255,255,255,0.4);
}

/* ========================================================
   表单消息样式
   ========================================================*/
.form-message {
    margin-top: var(--spacing-md);
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--radius);
    font-size: 14px;
    display: none;
}

.form-message-success {
    background: #d1fae5;
    color: #065f46;
    border: 1px solid #a7f3d0;
}

.form-message-error {
    background: #fee2e2;
    color: #991b1b;
    border: 1px solid #fca5a5;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(-10px); }
    to { opacity: 1; transform: translateY(0); }
}

/* ========================================================
   基础重置
   ========================================================*/
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: var(--font);
    font-size: 15px;
    line-height: 1.6;
    color: var(--text-main);
    background: var(--bg-main);
}

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

a:hover {
    color: var(--secondary);
}

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

/* ========================================================
   布局
   ========================================================*/
.container {
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

.main {
    padding-top: var(--header-height);
}

.grid-3 {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-md);
}

.grid-2 {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-md);
}

.grid-4 {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: var(--spacing-sm);
}

/* ========================================================
   双栏布局 (7:3)
   ========================================================*/
.two-column-layout {
    display: grid;
    grid-template-columns: 7fr 3fr;
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
}

.main-column {
    min-width: 0;
}

.sidebar-column {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

/* 侧边栏卡片 */
.sidebar-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: var(--spacing-md);
}

.sidebar-card h3 {
    font-size: 16px;
    font-weight: 600;
    color: var(--text-main);
    margin-bottom: var(--spacing-sm);
    padding-bottom: var(--spacing-sm);
    border-bottom: 1px solid var(--border-light);
}

.sidebar-card p {
    color: var(--text-sub);
    font-size: 14px;
    margin-bottom: var(--spacing-sm);
}

.sidebar-card.highlight {
    background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
    border-color: var(--primary);
    color: #fff;
}

.sidebar-card.highlight h3 {
    color: #fff;
    border-color: rgba(255,255,255,0.2);
}

.sidebar-card.highlight p {
    color: rgba(255,255,255,0.9);
}

/* 服务列表 */
.service-list {
    list-style: none;
}

.service-list li {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) 0;
    border-bottom: 1px solid var(--border-light);
    color: var(--text-sub);
    font-size: 14px;
}

.service-list li:last-child {
    border-bottom: none;
}

.service-icon {
    font-size: 18px;
}

/* 案例统计 */
.case-stats {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-md);
}

.case-stat {
    text-align: center;
    padding: var(--spacing-sm);
    background: var(--bg-main);
    border-radius: var(--radius);
}

.stat-num {
    font-size: 20px;
    font-weight: 700;
    color: var(--primary);
}

.stat-label {
    font-size: 12px;
    color: var(--text-sub);
}

/* 价值列表 */
.value-list {
    list-style: none;
}

.value-list li {
    padding: 8px 0;
    color: var(--text-sub);
    font-size: 14px;
}

/* 咨询热线 */
.hotline {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    margin: var(--spacing-md) 0;
}

.hotline-icon {
    font-size: 28px;
}

.hotline-number {
    font-size: 20px;
    font-weight: 700;
}

.hotline-desc {
    font-size: 13px;
    color: var(--text-light);
}

/* 流程步骤 */
.process-steps {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.process-step {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.step-num {
    width: 28px;
    height: 28px;
    background: var(--primary);
    color: #fff;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 14px;
    font-weight: 600;
}

.step-text {
    color: var(--text-sub);
    font-size: 14px;
}

/* 要求列表 */
.requirement-list {
    list-style: none;
}

.requirement-list li {
    padding: 6px 0;
    color: var(--text-sub);
    font-size: 14px;
}

/* 新增友链 */
.new-links {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.new-link-item {
    color: var(--primary);
    font-size: 14px;
    text-decoration: none;
}

.new-link-item:hover {
    text-decoration: underline;
}

/* 友链分类 */
.links-categories {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
}

.links-category {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
}

.links-category h3 {
    font-size: 18px;
    font-weight: 600;
    color: var(--text-main);
    margin-bottom: var(--spacing-md);
}

.links-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: var(--spacing-md);
}

.friend-link {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm);
    background: var(--bg-main);
    border: 1px solid var(--border-light);
    border-radius: var(--radius);
    text-decoration: none;
    transition: var(--transition);
}

.friend-link:hover {
    border-color: var(--primary);
    background: #fff;
    transform: translateY(-2px);
    box-shadow: var(--shadow);
}

.friend-icon {
    font-size: 28px;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.friend-info {
    flex: 1;
    min-width: 0;
}

.friend-name {
    font-weight: 500;
    color: var(--text-main);
    font-size: 15px;
    margin-bottom: 2px;
}

.friend-desc {
    font-size: 13px;
    color: var(--text-light);
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

/* 工作时间 */
.work-time {
    display: flex;
    justify-content: space-between;
    padding: var(--spacing-sm) 0;
    border-bottom: 1px solid var(--border-light);
}

.work-time:last-child {
    border-bottom: none;
}

.work-day {
    font-weight: 500;
    color: var(--text-main);
}

.work-hours {
    color: var(--text-sub);
}

/* 常见问题 */
.faq-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.faq-item {
    padding-bottom: var(--spacing-sm);
    border-bottom: 1px solid var(--border-light);
}

.faq-item:last-child {
    border-bottom: none;
}

.faq-q {
    font-weight: 500;
    color: var(--text-main);
    font-size: 14px;
    margin-bottom: 4px;
}

.faq-a {
    color: var(--text-light);
    font-size: 13px;
}

/* 社交链接 */
.social-links {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.social-link {
    padding: 8px 12px;
    background: var(--bg-main);
    border-radius: var(--radius);
    color: var(--text-sub);
    font-size: 14px;
    text-decoration: none;
    text-align: center;
    transition: var(--transition);
}

.social-link:hover {
    background: var(--primary);
    color: #fff;
}

/* ========================================================
   首页新增区域样式
   ========================================================*/
.home-services {
    padding: var(--spacing-lg) 0;
    background: var(--bg-card);
    border-top: 1px solid var(--border);
    border-bottom: 1px solid var(--border);
}

.why-us {
    padding: var(--spacing-lg) 0;
}

.feature-item {
    text-align: center;
    padding: var(--spacing-lg);
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
}

.feature-icon {
    font-size: 40px;
    margin-bottom: var(--spacing-md);
}

.feature-item h3 {
    font-size: 18px;
    font-weight: 600;
    color: var(--text-main);
    margin-bottom: var(--spacing-sm);
}

.feature-item p {
    color: var(--text-sub);
    font-size: 14px;
}

.testimonials {
    padding: var(--spacing-lg) 0;
    background: var(--bg-card);
    border-top: 1px solid var(--border);
}

.testimonial-card {
    background: var(--bg-main);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
}

.testimonial-stars {
    color: #ffc107;
    font-size: 18px;
    margin-bottom: var(--spacing-sm);
}

.testimonial-text {
    color: var(--text-main);
    font-size: 14px;
    line-height: 1.8;
    font-style: italic;
    margin-bottom: var(--spacing-md);
}

.testimonial-author {
    color: var(--text-sub);
    font-size: 13px;
    text-align: right;
}

/* 服务详情 */
.service-detail {
    display: none;
    margin-top: var(--spacing-md);
    padding-top: var(--spacing-md);
    border-top: 1px solid var(--border-light);
}

.service-detail p {
    color: var(--text-sub);
    font-size: 14px;
    margin-bottom: var(--spacing-md);
}

.service-detail ul {
    list-style: none;
}

.service-detail li {
    padding: 4px 0;
    padding-left: 16px;
    position: relative;
    color: var(--text-sub);
    font-size: 14px;
}

.service-detail li::before {
    content: '•';
    position: absolute;
    left: 0;
    color: var(--primary);
}

/* 服务网格 */
.services-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
}

/* ========================================================
   导航
   ========================================================*/
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: var(--header-height);
    background: var(--bg-card);
    border-bottom: 1px solid var(--border);
    z-index: 100;
}

.header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 100%;
}

.logo {
    font-size: 18px;
    font-weight: 600;
    color: var(--text-main);
}

.logo span {
    color: var(--primary);
}

/* 移动端菜单按钮 */
.mobile-menu-toggle {
    display: none;
    flex-direction: column;
    justify-content: space-between;
    width: 24px;
    height: 18px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0;
}

.mobile-menu-toggle span {
    display: block;
    width: 100%;
    height: 2px;
    background: var(--text-main);
    border-radius: 2px;
    transition: var(--transition);
}

.mobile-menu-toggle.active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
}

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

.mobile-menu-toggle.active span:nth-child(3) {
    transform: rotate(-45deg) translate(5px, -5px);
}

.nav {
    display: flex;
    gap: var(--spacing-sm);
}

.nav-btn {
    padding: 0 var(--spacing-md);
    height: 32px;
    border: none;
    background: none;
    color: var(--text-sub);
    font-size: 14px;
    cursor: pointer;
    border-radius: var(--radius);
    transition: var(--transition);
    min-width: 60px; /* 确保最小宽度一致 */
    display: inline-flex;
    align-items: center;
    justify-content: center;
    text-align: center;
}

.nav-btn:hover,
.nav-btn.active {
    background: var(--bg-main);
    color: var(--primary);
}

.nav-btn.active {
    font-weight: 600;
    min-width: 60px; /* 确保激活状态下宽度也一致 */
    display: inline-flex;
    align-items: center;
    justify-content: center;
    text-align: center;
}

/* ========================================================
   页面分区
   ========================================================*/
.section {
    display: none;
    padding: var(--spacing-lg) 0;
}

.section.active {
    display: block;
}

.section-header {
    text-align: center;
    margin-bottom: var(--spacing-lg);
}

.section-header h2 {
    font-size: 28px;
    font-weight: 600;
    color: var(--text-main);
    margin-bottom: var(--spacing-sm);
}

.section-header p {
    color: var(--text-sub);
    font-size: 16px;
}

/* ========================================================
   Hero区
   ========================================================*/
.hero {
    background: var(--bg-card);
    padding: var(--spacing-lg) 0;
    text-align: center;
}

.hero h1 {
    font-size: 36px;
    font-weight: 700;
    color: var(--text-main);
    margin-bottom: var(--spacing-sm);
}

.hero p {
    font-size: 18px;
    color: var(--text-sub);
    margin-bottom: var(--spacing-lg);
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.hero-stats {
    display: flex;
    justify-content: center;
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
}

.stat {
    text-align: center;
}

.stat .num {
    font-size: 28px;
    font-weight: 700;
    color: var(--primary);
}

.stat .label {
    font-size: 13px;
    color: var(--text-sub);
}

.hero-actions {
    display: flex;
    justify-content: center;
    gap: var(--spacing-md);
}

/* ========================================================
   按钮系统
   ========================================================*/
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    padding: 10px 24px;
    border: none;
    border-radius: var(--radius);
    font-size: 15px;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    text-decoration: none;
}

.btn-primary {
    background: var(--primary);
    color: #fff;
}

.btn-primary:hover {
    background: var(--secondary);
}

.btn-outline {
    background: transparent;
    color: var(--primary);
    border: 1px solid var(--border);
}

.btn-outline:hover {
    background: var(--bg-main);
    border-color: var(--primary);
}

.btn-accent {
    background: var(--accent);
    color: #fff;
}

.btn-accent:hover {
    filter: brightness(0.9);
}

.btn-lg {
    padding: 14px 32px;
    font-size: 16px;
}

.btn-block {
    width: 100%;
}

/* ========================================================
   卡片系统
   ========================================================*/
.card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    transition: var(--transition);
}

.card:hover {
    border-color: var(--primary);
    box-shadow: var(--shadow-hover);
}

.service-card {
    text-align: center;
}

.service-card .icon {
    font-size: 36px;
    margin-bottom: var(--spacing-md);
}

.service-card h3 {
    font-size: 18px;
    color: var(--text-main);
    margin-bottom: var(--spacing-sm);
}

.service-card p {
    color: var(--text-sub);
    font-size: 14px;
}

/* ========================================================
   表单系统
   ========================================================*/
.form-group {
    margin-bottom: var(--spacing-md);
}

.form-group label {
    display: block;
    margin-bottom: 6px;
    font-weight: 500;
    color: var(--text-main);
    font-size: 14px;
}

.form-input,
.form-textarea {
    width: 100%;
    padding: 10px 12px;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    font-size: 15px;
    font-family: var(--font);
    background: var(--bg-input);
    transition: var(--transition);
}

.form-input:focus,
.form-textarea:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 2px rgba(0,0,0,0.03);
}

.form-textarea {
    min-height: 100px;
    resize: vertical;
}

/* 验证码 */
.captcha-row {
    display: flex;
    gap: var(--spacing-sm);
}

.captcha-display {
    padding: 0;
    background: var(--bg-main);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    font-family: 'Courier New', monospace;
    font-size: 18px;
    letter-spacing: 2px;
    cursor: pointer;
    user-select: none;
    min-width: 100px;
    height: 42px;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
}

.captcha-display:hover {
    background: var(--border-light);
}

.captcha-display img {
    width: 100%;
    height: 100%;
    object-fit: contain;
}

/* ========================================================
   联系区
   ========================================================*/
.contact-grid {
    display: grid;
    grid-template-columns: 2fr 1fr; /* 在线留言占2份，联系方式占1份 */
    gap: var(--spacing-md);
}

.contact-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    padding: var(--spacing-md);
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    margin-bottom: var(--spacing-sm);
}

.contact-item .icon {
    font-size: 20px;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--bg-main);
    border-radius: var(--radius);
}

.contact-item .info h4 {
    font-size: 12px;
    color: var(--text-sub);
    margin-bottom: 2px;
}

.contact-item .info strong {
    font-size: 15px;
    color: var(--text-main);
}

/* ========================================================
   投资区
   ========================================================*/
.investment-section {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
}

.investment-header {
    margin-bottom: var(--spacing-lg);
}

.investment-header h3 {
    font-size: 20px;
    color: var(--text-main);
    margin-bottom: var(--spacing-sm);
}

.investment-desc {
    color: var(--text-sub);
    margin-bottom: var(--spacing-md);
}

.invest-tags {
    display: flex;
    gap: var(--spacing-sm);
    flex-wrap: wrap;
    margin-bottom: var(--spacing-lg);
}

.invest-tag {
    padding: 4px 12px;
    background: var(--bg-main);
    border-radius: 20px;
    font-size: 13px;
    color: var(--text-sub);
}

.invest-options {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-md);
}

.invest-option {
    padding: var(--spacing-md);
    background: var(--bg-main);
    border: 1px solid var(--border);
    border-radius: var(--radius);
}

.invest-option h4 {
    font-size: 16px;
    color: var(--text-main);
    margin-bottom: 4px;
}

.invest-option p {
    font-size: 14px;
    color: var(--text-sub);
}

/* ========================================================
   页脚
   ========================================================*/
.footer {
    background: var(--bg-card);
    border-top: 1px solid var(--border);
    padding: var(--spacing-lg) 0;
    margin-top: var(--spacing-lg);
}

.footer .container {
    text-align: center;
}

.footer p {
    color: var(--text-sub);
    margin-bottom: var(--spacing-sm);
}

.footer-links {
    display: flex;
    justify-content: center;
    gap: var(--spacing-md);
}

.footer-links a {
    color: var(--text-sub);
    font-size: 14px;
}

.footer-links a:hover {
    color: var(--primary);
}

/* ========================================================
   辅助类
   ========================================================*/
.text-center { text-align: center; }
.text-muted { color: var(--text-sub); }
.text-primary { color: var(--primary); }
.mt-lg { margin-top: var(--spacing-lg); }
.mb-md { margin-bottom: var(--spacing-md); }
.mb-lg { margin-bottom: var(--spacing-lg); }
.flex { display: flex; }
.flex-center { display: flex; align-items: center; justify-content: center; }
.hidden { display: none; }

/* ========================================================
   响应式
   ========================================================*/
@media (max-width: 768px) {
    :root {
        --container-width: 100%;
        --spacing-md: 16px;
        --spacing-lg: 24px;
    }

    .header .container {
        padding: 0 var(--spacing-md);
    }

    /* 显示移动端菜单按钮 */
    .mobile-menu-toggle {
        display: flex;
    }

    .nav {
        display: none;
        position: absolute;
        top: var(--header-height);
        left: 0;
        right: 0;
        background: var(--bg-card);
        flex-direction: column;
        padding: var(--spacing-md);
        border-bottom: 1px solid var(--border);
        gap: var(--spacing-sm);
        box-shadow: var(--shadow);
    }

    .nav.active {
        display: flex;
    }

    .nav-btn {
        width: 100%;
        height: 44px;
        padding: 0 var(--spacing-md);
        text-align: center; /* 保持与桌面端一致的居中对齐 */
        display: flex;
        align-items: center;
        justify-content: center;
    }

    /* 双栏布局变为单栏 */
    .two-column-layout {
        grid-template-columns: 1fr;
    }

    /* 首页响应式 */
    .hero h1 {
        font-size: 24px;
    }

    .hero p {
        font-size: 15px;
    }

    .hero-stats {
        flex-direction: column;
        gap: var(--spacing-md);
    }

    .hero-actions {
        flex-direction: column;
    }

    .grid-3,
    .grid-4 {
        grid-template-columns: 1fr;
    }

    .grid-2 {
        grid-template-columns: 1fr;
    }

    .links-grid {
        grid-template-columns: 1fr;
    }

    .services-grid {
        grid-template-columns: 1fr;
    }

    .contact-grid {
        grid-template-columns: 1fr;
    }

    .invest-options {
        grid-template-columns: 1fr;
    }

    /* 侧边栏在移动端调整 */
    .sidebar-column {
        order: -1;
    }

    .case-stats {
        grid-template-columns: repeat(4, 1fr);
        gap: var(--spacing-sm);
    }

    .stat-num {
        font-size: 16px;
    }

    /* 顶部Banner广告在移动端调整 */
    .top-banner-ad {
        top: var(--header-height);
        border-radius: 0;
    }

    /* 侧栏广告在移动端不悬浮 */
    .sidebar-sticky-ad {
        position: relative;
        top: 0;
        order: -1;
        margin-bottom: var(--spacing-md);
    }
}