@import url('https://fonts.googleapis.com/css2?family=Noto+Sans+SC:wght@300;400;500;700&display=swap');

:root {
    --primary-color: #0A4ABF;
    --secondary-color: #1E3A8A;
    --accent-color: #0EA5E9;
    --accent-orange: #F59E0B;
    --dark-color: #0f172a;
    --light-color: #f8fafc;
    --tech-bg: #f0f4f8;
    --glow-color: rgba(10, 74, 191, 0.3);
    --grid-color: rgba(14, 165, 233, 0.1);
    --text-color: #1e293b;
    --text-light: #475569;
    --text-lighter: #94a3b8;
    --neutral-100: #f8fafc;
    --neutral-200: #e6eef6;
    --neutral-300: #d1dce5;
    --neutral-400: #94a3b8;
    --neutral-500: #64748b;
    --neutral-600: #475569;
    --neutral-700: #334155;
    --neutral-800: #1e293b;
    --neutral-900: #0f172a;
}

/* 通用过渡效果 */
.transition {
    transition: all 0.2s ease;
}

/* 触摸交互优化 */
@media (max-width: 768px) {
    /* 增加按钮触摸区域 */
    .btn-primary,
    .btn-secondary {
        padding: 14px 28px;
        font-size: 16px;
        min-height: 48px;
    }
    
    /* 增加导航链接触摸区域 */
    .nav-link {
        padding: 12px 20px;
        min-height: 44px;
        display: inline-flex;
        align-items: center;
    }
    
    /* 增加移动端菜单按钮触摸区域 */
    #menu-toggle {
        padding: 12px;
        min-width: 44px;
        min-height: 44px;
        display: flex;
        align-items: center;
        justify-content: center;
    }
    
    /* 增加轮播图控制按钮触摸区域 */
    .carousel-control {
        width: 48px;
        height: 48px;
    }
    
    /* 增加服务卡片触摸区域 */
    .service-card {
        min-height: 200px;
        display: flex;
        flex-direction: column;
        justify-content: center;
    }
    
    /* 增加FAQ问题触摸区域 */
    .faq-question {
        min-height: 60px;
        display: flex;
        align-items: center;
    }
    
    /* 增加联系信息触摸区域 */
    .contact-info {
        min-height: 80px;
    }
    
    /* 增加社交图标触摸区域 */
    .social-icon {
        width: 48px;
        height: 48px;
    }
    
    /* 增加返回顶部按钮触摸区域 */
    #back-to-top {
        width: 56px;
        height: 56px;
    }
    
    /* 触摸反馈优化 */
    button,
    a,
    .faq-question {
        -webkit-tap-highlight-color: rgba(0, 0, 0, 0.1);
    }
    
    /* 禁用双击缩放 */
    * {
        touch-action: manipulation;
    }
}

body {
    font-family: 'Noto Sans SC', sans-serif;
    background-color: var(--neutral-100);
    color: var(--text-color);
    line-height: 1.6;
    font-size: 16px;
}

section {
    padding: 40px 0;
}

/* 首屏英雄区域保持原有高度 */
.hero-section {
    padding: 0;
}

nav {
    backdrop-filter: blur-md;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    position: fixed;
    width: 100%;
    z-index: 50;
}

nav .nav-link {
    color: rgba(255, 255, 255, 0.9) !important;
}

nav .nav-link:hover {
    color: var(--accent-color) !important;
    background: rgba(255, 255, 255, 0.1) !important;
}

nav .active-nav {
    color: var(--accent-color) !important;
    background: rgba(255, 255, 255, 0.1) !important;
    font-weight: 500;
}

nav .text-gradient {
    color: white !important;
    background: none !important;
    -webkit-text-fill-color: white !important;
}

#menu-toggle {
    color: white !important;
}

#menu-toggle:hover {
    color: var(--accent-color) !important;
}

#mobile-menu {
    border: 1px solid rgba(255, 255, 255, 0.2) !important;
    border-radius: 8px;
    overflow: hidden;
}

#mobile-menu a {
    color: rgba(255, 255, 255, 0.9) !important;
    padding: 12px 16px;
    display: block;
    font-size: 16px;
    line-height: 1.5;
}

#mobile-menu a:hover {
    color: var(--accent-color) !important;
    background: rgba(255, 255, 255, 0.1) !important;
}

#mobile-menu a:active {
    background: rgba(255, 255, 255, 0.15) !important;
}

.bg-gradient {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
}

.text-gradient {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.tech-bg {
    background: var(--tech-bg);
    position: relative;
    overflow: hidden;
}

.tech-bg::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-image: 
        linear-gradient(rgba(0, 102, 204, 0.1) 1px, transparent 1px),
        linear-gradient(90deg, rgba(0, 102, 204, 0.1) 1px, transparent 1px);
    background-size: 20px 20px;
    z-index: 0;
}

.tech-card {
    position: relative;
    overflow: hidden;
}

.tech-card::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: linear-gradient(45deg, transparent, rgba(0, 212, 255, 0.1), transparent);
    transform: rotate(45deg);
    animation: tech-glow 6s linear infinite;
    z-index: 0;
}

@keyframes tech-glow {
    0% { transform: translateX(-100%) rotate(45deg); }
    100% { transform: translateX(100%) rotate(45deg); }
}

.glow-effect {
    box-shadow: 0 0 20px var(--glow-color);
}

.tech-border {
    position: relative;
}

.tech-border::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    border: 1px solid rgba(0, 212, 255, 0.3);
    border-radius: inherit;
    pointer-events: none;
}

.card {
    background: white;
    border-radius: 12px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
    border: 1px solid var(--neutral-200);
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
    padding: 24px;
}

.card:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 12px -3px rgba(14, 165, 233, 0.1), 0 4px 6px -2px rgba(14, 165, 233, 0.05);
    border-color: var(--primary-color);
}

.card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
    transform: scaleX(0);
    transition: transform 0.3s ease;
}

.card:hover::before {
    transform: scaleX(1);
}

.btn-primary {
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: 8px;
    padding: 12px 24px;
    font-weight: 500;
    transition: all 0.3s ease;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    font-size: 16px;
}

.btn-primary:hover {
    background: var(--secondary-color);
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.15);
}

.btn-primary:focus {
    outline: none;
    box-shadow: 0 0 0 3px rgba(10, 74, 191, 0.3);
}

.btn-secondary {
    background: transparent;
    color: white;
    border: 2px solid white;
    border-radius: 8px;
    padding: 12px 24px;
    font-weight: 500;
    transition: all 0.3s ease;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    font-size: 16px;
}

.btn-secondary:hover {
    background: white;
    color: var(--primary-color);
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.15);
}

.btn-secondary:focus {
    outline: none;
    box-shadow: 0 0 0 3px rgba(255, 255, 255, 0.3);
}

html {
    scroll-behavior: smooth;
}

.nav-link {
    position: relative;
    padding: 10px 18px;
    color: var(--text-color);
    transition: all 0.3s ease;
    font-weight: 400;
    border-radius: 8px;
    text-decoration: none;
    display: inline-block;
}

.nav-link:hover {
    color: var(--primary-color);
    background: rgba(14, 165, 233, 0.05);
    transform: translateY(-1px);
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 0;
    height: 2px;
    background: var(--primary-color);
    transition: width 0.3s ease;
}

.nav-link:hover::after {
    width: 80%;
}

.active-nav {
    color: var(--primary-color);
    font-weight: 500;
    background: rgba(14, 165, 233, 0.05);
}

.active-nav::after {
    width: 80%;
}

.hero-section {
    background: linear-gradient(135deg, var(--dark-color), var(--primary-color));
    position: relative;
    height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    text-align: center;
    overflow: hidden;
}

.hero-section::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: radial-gradient(circle at 50% 50%, rgba(255, 255, 255, 0.1) 0%, rgba(255, 255, 255, 0) 70%);
    z-index: 1;
}

.hero-section::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><defs><pattern id="grid" width="20" height="20" patternUnits="userSpaceOnUse"><path d="M 20 0 L 0 0 0 20" fill="none" stroke="rgba(255,255,255,0.05)" stroke-width="0.5"/></pattern></defs><rect width="100" height="100" fill="url(%23grid)"/></svg>');
    z-index: 1;
}

.hero-content {
    position: relative;
    z-index: 2;
    max-width: 800px;
    padding: 0 20px;
}

.hero-title {
    font-size: clamp(2.5rem, 5vw, 4rem);
    font-weight: 700;
    margin-bottom: 24px;
    line-height: 1.1;
    letter-spacing: -0.025em;
}

.hero-subtitle {
    font-size: clamp(1rem, 2vw, 1.5rem);
    margin-bottom: 40px;
    opacity: 1;
    color: white;
    text-shadow: 0 1px 2px rgba(0, 0, 0, 0.2);
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.hero-btn {
}

.section-title {
    position: relative;
    display: inline-block;
    margin-bottom: 48px;
    font-size: clamp(1.75rem, 3vw, 2.5rem);
    font-weight: 700;
    color: var(--dark-color);
    letter-spacing: -0.025em;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: -12px;
    left: 0;
    width: 60px;
    height: 3px;
    background: linear-gradient(90deg, var(--primary-color), var(--accent-color));
    border-radius: 2px;
}

h3 {
    font-weight: 600;
    color: var(--neutral-800);
    margin-bottom: 1.25rem;
    font-size: 1.5rem;
    line-height: 1.4;
}

h4 {
    font-weight: 500;
    color: var(--neutral-700);
    margin-bottom: 0.75rem;
    font-size: 1.25rem;
    line-height: 1.5;
}

p {
    line-height: 1.7;
    color: var(--neutral-600);
    margin-bottom: 1rem;
}

.text-light {
    color: var(--text-lighter);
}

.text-lg {
    font-size: 1.125rem;
    line-height: 1.7;
}

.text-xl {
    font-size: 1.25rem;
    line-height: 1.6;
}

.text-2xl {
    font-size: 1.5rem;
    line-height: 1.4;
    font-weight: 600;
    color: var(--neutral-800);
}

.carousel {
    position: relative;
    overflow: hidden;
    border-radius: 16px;
    height: 400px;
    box-shadow: 0 10px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    touch-action: pan-y;
}

/* 移动端轮播图优化 */
@media (max-width: 768px) {
    .carousel {
        height: 250px;
    }
    
    .carousel-caption h3 {
        font-size: 1.2rem;
    }
    
    .carousel-caption p {
        font-size: 0.9rem;
    }
    
    .carousel-control {
        width: 40px;
        height: 40px;
        font-size: 16px;
    }
    
    .carousel-control-prev {
        left: 16px;
    }
    
    .carousel-control-next {
        right: 16px;
    }
}

.carousel-inner {
    display: flex;
    transition: transform 0.5s ease;
    height: 100%;
}

.carousel-item {
    min-width: 100%;
    height: 100%;
    position: relative;
}

.carousel-item img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.carousel-caption {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    background: linear-gradient(to top, rgba(0, 0, 0, 0.85), transparent);
    color: white;
    padding: 40px;
}

.carousel-caption h3 {
    color: white;
    margin-bottom: 12px;
    font-size: 1.75rem;
    font-weight: 600;
}

.carousel-caption p {
    color: rgba(255, 255, 255, 0.9);
    margin-bottom: 0;
    font-size: 1.125rem;
}

.carousel-control {
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    width: 48px;
    height: 48px;
    background: rgba(255, 255, 255, 0.95);
    border: none;
    border-radius: 50%;
    color: var(--primary-color);
    font-size: 18px;
    cursor: pointer;
    transition: all 0.3s ease;
    z-index: 10;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
}

.carousel-control:hover {
    background: white;
    transform: translateY(-50%) scale(1.1);
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
}

.carousel-control-prev {
    left: 24px;
}

.carousel-control-next {
    right: 24px;
}

.service-icon {
    width: 72px;
    height: 72px;
    border-radius: 16px;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 20px;
    font-size: 28px;
    color: white;
    box-shadow: 0 4px 6px -1px rgba(14, 165, 233, 0.1), 0 2px 4px -1px rgba(14, 165, 233, 0.06);
    transition: all 0.3s ease;
}

.service-card:hover .service-icon {
    transform: translateY(-3px) scale(1.02);
    box-shadow: 0 6px 10px -3px rgba(14, 165, 233, 0.1), 0 2px 4px -2px rgba(14, 165, 233, 0.05);
}

.service-card {
    padding: 24px;
    text-align: center;
    border-radius: 12px;
    touch-action: manipulation;
}

.service-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.08);
}

.service-card:active {
    transform: translateY(0);
}

/* 移动端服务卡片优化 */
@media (max-width: 768px) {
    .service-card {
        padding: 20px;
    }
    
    .service-icon {
        width: 64px;
        height: 64px;
        font-size: 24px;
    }
    
    .service-card h3 {
        font-size: 1.25rem;
    }
}

.process-step {
    position: relative;
    padding: 24px;
    border-radius: 16px;
    background: white;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
    transition: all 0.3s ease;
    z-index: 1;
    border: 1px solid var(--neutral-200);
    touch-action: manipulation;
}

.process-step:hover {
    transform: translateY(-3px);
    box-shadow: 0 6px 10px -3px rgba(14, 165, 233, 0.1), 0 2px 4px -2px rgba(14, 165, 233, 0.05);
    border-color: var(--primary-color);
}

.process-step:active {
    transform: translateY(0);
}

/* 移动端流程步骤优化 */
@media (max-width: 768px) {
    .process-step {
        padding: 20px;
        text-align: center;
    }
    
    .step-number {
        width: 48px;
        height: 48px;
        font-size: 1.1rem;
        margin: 0 auto 16px;
    }
    
    .process-step h3 {
        font-size: 1.1rem;
        margin-bottom: 8px;
    }
    
    .process-step p {
        font-size: 0.9rem;
    }
}

.process-step::after {
    content: '';
    position: absolute;
    top: 50%;
    right: -30px;
    width: 60px;
    height: 2px;
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
    transform: translateY(-50%);
    z-index: -1;
}

.process-step:last-child::after {
    display: none;
}

.step-number {
    width: 56px;
    height: 56px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    margin-bottom: 20px;
    box-shadow: 0 4px 6px -1px rgba(14, 165, 233, 0.1), 0 2px 4px -1px rgba(14, 165, 233, 0.06);
    font-size: 1.25rem;
}

.faq-item {
    margin-bottom: 16px;
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
    border: 1px solid var(--neutral-200);
}

.faq-question {
    background: white;
    padding: 24px;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: all 0.3s ease;
    touch-action: manipulation;
}

.faq-question:hover {
    background: var(--neutral-100);
}

.faq-question:active {
    background: var(--neutral-100);
}

/* 移动端 FAQ 优化 */
@media (max-width: 768px) {
    .faq-question {
        padding: 16px 20px;
    }
    
    .faq-question h3 {
        font-size: 1rem;
    }
    
    .faq-answer {
        padding: 0 20px;
    }
    
    .faq-answer.active {
        padding: 16px 20px;
    }
    
    .faq-answer p {
        font-size: 0.9rem;
    }
}

.faq-answer {
    background: white;
    padding: 0 24px;
    max-height: 0;
    overflow: hidden;
    transition: all 0.3s ease;
}

.faq-answer.active {
    max-height: 250px;
    padding: 24px;
    border-top: 1px solid var(--neutral-200);
}

.contact-info {
    display: flex;
    align-items: center;
    margin-bottom: 24px;
    padding: 20px;
    background: white;
    border-radius: 12px;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
    border: 1px solid var(--neutral-200);
    transition: all 0.3s ease;
}

.contact-info:hover {
    transform: translateY(-3px);
    box-shadow: 0 4px 6px -1px rgba(14, 165, 233, 0.1), 0 2px 4px -1px rgba(14, 165, 233, 0.06);
    border-color: var(--primary-color);
}

.contact-icon {
    width: 56px;
    height: 56px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    display: flex;
    align-items: center;
    justify-content: center;
    margin-right: 20px;
    font-size: 22px;
    color: white;
    box-shadow: 0 4px 6px -1px rgba(14, 165, 233, 0.1), 0 2px 4px -1px rgba(14, 165, 233, 0.06);
}

.footer {
    background: var(--dark-color);
    color: white;
    padding: 80px 0 40px;
}

.footer-logo {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: 24px;
    color: white;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.footer-links h4 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 24px;
    color: white;
    position: relative;
    padding-bottom: 12px;
}

.footer-links h4::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 40px;
    height: 2px;
    background: var(--primary-color);
    border-radius: 1px;
}

.footer-links ul {
    list-style: none;
    padding: 0;
}

.footer-links li {
    margin-bottom: 12px;
}

.footer-links a {
    color: var(--neutral-400);
    transition: all 0.3s ease;
    text-decoration: none;
    display: inline-block;
}

.footer-links a:hover {
    color: var(--accent-color);
    padding-left: 8px;
}

.social-icons {
    display: flex;
    gap: 16px;
    margin-top: 24px;
}

.social-icon {
    width: 44px;
    height: 44px;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.08);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    transition: all 0.3s ease;
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.social-icon:hover {
    background: var(--primary-color);
    transform: translateY(-4px);
    border-color: var(--primary-color);
}

.copyright {
    text-align: center;
    padding-top: 40px;
    border-top: 1px solid rgba(255, 255, 255, 0.08);
    margin-top: 40px;
    color: var(--neutral-500);
    font-size: 0.875rem;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .hero-title {
        font-size: 2.5rem;
    }
    
    .hero-subtitle {
        font-size: 1.2rem;
    }
    
    .section-title {
        font-size: 1.8rem;
        margin-bottom: 32px;
    }
    
    .carousel {
        height: 300px;
    }
    
    .process-step {
        margin-bottom: 30px;
    }
    
    .process-step::after {
        top: auto;
        bottom: -25px;
        right: 50%;
        width: 2px;
        height: 50px;
        transform: translateX(50%);
    }
    
    .process-step:last-child::after {
        display: none;
    }
    
    /* 手机端字体大小调整 */
    h3 {
        font-size: 1.25rem;
        margin-bottom: 1rem;
    }
    
    h4 {
        font-size: 1.1rem;
        margin-bottom: 0.5rem;
    }
    
    p {
        font-size: 0.95rem;
        line-height: 1.6;
    }
    
    .text-lg {
        font-size: 1rem;
    }
    
    .text-xl {
        font-size: 1.125rem;
    }
    
    /* 手机端间距调整 */
    section {
        padding: 32px 0;
    }
    
    .container {
        padding-left: 16px;
        padding-right: 16px;
    }
    
    .card {
        padding: 20px;
    }
}

@media (max-width: 576px) {
    .hero-title {
        font-size: 2rem;
    }
    
    .hero-subtitle {
        font-size: 1rem;
    }
    
    .section-title {
        font-size: 1.5rem;
        margin-bottom: 24px;
    }
    
    .carousel {
        height: 250px;
    }
    
    /* 小屏幕手机字体大小调整 */
    h3 {
        font-size: 1.15rem;
    }
    
    h4 {
        font-size: 1rem;
    }
    
    p {
        font-size: 0.9rem;
    }
    
    /* 小屏幕手机间距调整 */
    section {
        padding: 24px 0;
    }
    
    .card {
        padding: 16px;
    }
    
    .service-card {
        padding: 16px;
    }
}

/* 表格样式 */
table {
    min-width: 100%;
    background: white;
    border-collapse: collapse;
}

th {
    padding: 12px 16px;
    background: var(--neutral-100);
    text-align: left;
    font-size: 14px;
    font-weight: 500;
    color: var(--neutral-700);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    border-bottom: 2px solid var(--neutral-200);
}

td {
    padding: 12px 16px;
    border-bottom: 1px solid var(--neutral-200);
    color: var(--neutral-600);
}

tbody tr:hover {
    background: var(--neutral-100);
    transition: background 0.3s ease;
}

/* 返回顶部按钮 */
#back-to-top {
    position: fixed;
    bottom: 32px;
    right: 32px;
    background: var(--primary-color);
    color: white;
    width: 48px;
    height: 48px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.15);
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
    z-index: 50;
    touch-action: manipulation;
}

#back-to-top:hover {
    background: var(--secondary-color);
    transform: translateY(-4px);
    box-shadow: 0 6px 12px rgba(14, 165, 233, 0.2);
}

#back-to-top:active {
    transform: translateY(-2px);
}

#back-to-top.visible {
    opacity: 1;
    visibility: visible;
    animation: fadeIn 0.3s ease;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* 移动端返回顶部按钮优化 */
@media (max-width: 768px) {
    #back-to-top {
        bottom: 24px;
        right: 24px;
        width: 44px;
        height: 44px;
    }
}