:root {
    --primary: #2563eb;
    --primary-dark: #1d4ed8;
    --primary-light: #dbeafe;
    --accent: #10b981;
    --accent-dark: #059669;
    --accent-light: #d1fae5;
    --dark: #111827;
    --dark-soft: #1f2937;
    --gray-50: #f9fafb;
    --gray-100: #f3f4f6;
    --gray-200: #e5e7eb;
    --gray-300: #d1d5db;
    --gray-400: #9ca3af;
    --gray-500: #6b7280;
    --gray-600: #4b5563;
    --gray-700: #374151;
    --gray-800: #1f2937;
    --white: #ffffff;
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow: 0 1px 3px rgba(0, 0, 0, 0.1), 0 1px 2px rgba(0, 0, 0, 0.06);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.07), 0 2px 4px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.1), 0 4px 10px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 50px rgba(0, 0, 0, 0.12);
    --radius-sm: 6px;
    --radius: 12px;
    --radius-lg: 20px;
    --radius-full: 9999px;
    --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

html {
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
}

body {
    font-family: "Microsoft YaHei", "PingFang SC", "Noto Sans SC", -apple-system, BlinkMacSystemFont, sans-serif;
    color: var(--gray-700);
    line-height: 1.7;
    background: var(--white);
    overflow-x: hidden;
}

.container {
    width: 90%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 80px 0;
}

/* ==================== Navbar ==================== */
.navbar {
    position: fixed;
    top: 0;
    width: 100%;
    z-index: 1000;
    padding: 16px 0;
    transition: all var(--transition);
    backdrop-filter: blur(0px);
}

.navbar.scrolled {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(20px);
    box-shadow: var(--shadow-md);
    padding: 10px 0;
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0;
}

.logo {
    font-size: 24px;
    font-weight: 800;
    color: var(--white);
    text-decoration: none;
    letter-spacing: -0.5px;
    transition: color var(--transition);
}

.navbar.scrolled .logo {
    color: var(--dark);
}

.logo span {
    color: var(--accent);
    font-weight: 600;
}

nav ul {
    list-style: none;
    display: flex;
    align-items: center;
    gap: 6px;
}

nav ul li a {
    color: rgba(255, 255, 255, 0.9);
    text-decoration: none;
    font-weight: 500;
    font-size: 15px;
    padding: 8px 16px;
    border-radius: var(--radius-full);
    transition: all var(--transition);
    position: relative;
}

.navbar.scrolled nav ul li a {
    color: var(--gray-600);
}

nav ul li a:hover {
    color: var(--white);
    background: rgba(255, 255, 255, 0.15);
}

.navbar.scrolled nav ul li a:hover {
    color: var(--primary);
    background: var(--primary-light);
}

nav ul li a.active {
    color: var(--white);
    background: var(--accent);
    font-weight: 600;
}

.navbar.scrolled nav ul li a.active {
    color: var(--white);
    background: var(--accent);
}

/* ==================== Hero (首页) ==================== */
.hero {
    height: 100vh;
    min-height: 600px;
    background: linear-gradient(135deg, rgba(37, 99, 235, 0.88) 0%, rgba(16, 185, 129, 0.75) 100%),
        url('https://images.unsplash.com/photo-1550745165-9bc0b252726f?q=80&w=2070') no-repeat center/cover;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    color: var(--white);
    position: relative;
}

.hero::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    height: 120px;
    background: linear-gradient(to top, rgba(255, 255, 255, 0.08), transparent);
}

.hero-content {
    position: relative;
    z-index: 1;
    animation: fadeInUp 0.8s ease-out;
}

.hero h1 {
    font-size: 52px;
    font-weight: 800;
    margin-bottom: 20px;
    letter-spacing: -1px;
    line-height: 1.2;
}

.hero p {
    font-size: 19px;
    max-width: 650px;
    margin: 0 auto 36px;
    opacity: 0.92;
    line-height: 1.8;
}

/* ==================== Page Hero (子页面) ==================== */
.page-hero {
    background: linear-gradient(135deg, var(--primary) 0%, #7c3aed 100%);
    padding: 120px 0 60px;
    text-align: center;
    color: var(--white);
    position: relative;
    overflow: hidden;
}

.page-hero::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -20%;
    width: 600px;
    height: 600px;
    background: radial-gradient(circle, rgba(255, 255, 255, 0.08) 0%, transparent 70%);
    border-radius: 50%;
}

.page-hero::after {
    content: '';
    position: absolute;
    bottom: -30%;
    left: -10%;
    width: 400px;
    height: 400px;
    background: radial-gradient(circle, rgba(16, 185, 129, 0.2) 0%, transparent 70%);
    border-radius: 50%;
}

.page-hero .container {
    padding: 20px 0;
}

.page-hero h1 {
    font-size: 40px;
    font-weight: 800;
    margin-bottom: 12px;
    letter-spacing: -0.5px;
    animation: fadeInUp 0.6s ease-out;
}

.page-hero p {
    font-size: 18px;
    opacity: 0.88;
    max-width: 600px;
    margin: 0 auto;
    animation: fadeInUp 0.6s ease-out 0.15s both;
}

/* ==================== Buttons ==================== */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background: var(--accent);
    color: var(--white);
    padding: 14px 36px;
    border-radius: var(--radius-full);
    text-decoration: none;
    font-weight: 600;
    font-size: 16px;
    letter-spacing: 0.3px;
    border: none;
    cursor: pointer;
    transition: all var(--transition);
    box-shadow: 0 4px 15px rgba(16, 185, 129, 0.3);
}

.btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(16, 185, 129, 0.4);
    background: var(--accent-dark);
}

.btn-outline {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    border: 2px solid var(--primary);
    color: var(--primary);
    padding: 12px 30px;
    border-radius: var(--radius-full);
    text-decoration: none;
    font-weight: 600;
    font-size: 15px;
    transition: all var(--transition);
}

.btn-outline:hover {
    background: var(--primary);
    color: var(--white);
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(37, 99, 235, 0.25);
}

/* ==================== Section Styles ==================== */
.section-title {
    text-align: center;
    font-size: 36px;
    font-weight: 800;
    margin-bottom: 16px;
    color: var(--dark);
    letter-spacing: -0.5px;
}

.section-subtitle {
    text-align: center;
    font-size: 17px;
    color: var(--gray-500);
    max-width: 600px;
    margin: 0 auto 50px;
}

/* ==================== Feature Cards (首页 + 解决方案) ==================== */
.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(290px, 1fr));
    gap: 28px;
}

.feature-card {
    background: var(--white);
    padding: 44px 32px;
    border-radius: var(--radius-lg);
    text-align: center;
    box-shadow: var(--shadow);
    transition: all var(--transition);
    border: 1px solid var(--gray-100);
    position: relative;
    overflow: hidden;
}

.feature-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: linear-gradient(90deg, var(--primary), var(--accent));
    transform: scaleX(0);
    transform-origin: left;
    transition: transform var(--transition);
}

.feature-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-xl);
    border-color: transparent;
}

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

.feature-card i {
    font-size: 44px;
    background: linear-gradient(135deg, var(--primary), var(--accent));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 20px;
    display: inline-block;
}

.feature-card h3 {
    margin-bottom: 12px;
    color: var(--dark);
    font-size: 20px;
    font-weight: 700;
}

.feature-card p {
    color: var(--gray-500);
    font-size: 15px;
    line-height: 1.7;
}

/* ==================== About Preview (首页) ==================== */
.about-preview {
    background: var(--gray-50);
    position: relative;
}

.about-preview .container {
    display: flex;
    align-items: center;
    gap: 80px;
}

.about-text {
    flex: 1;
}

.about-text h2 {
    font-size: 32px;
    font-weight: 800;
    color: var(--dark);
    margin-bottom: 16px;
}

.about-text p {
    font-size: 17px;
    color: var(--gray-500);
    line-height: 1.8;
    margin-bottom: 24px;
}

.about-stats {
    flex: 1;
    display: flex;
    justify-content: space-around;
    text-align: center;
    gap: 20px;
}

.stat-item {
    background: var(--white);
    padding: 32px 24px;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow);
    flex: 1;
    transition: transform var(--transition);
}

.stat-item:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.stat-item h3 {
    font-size: 44px;
    font-weight: 800;
    background: linear-gradient(135deg, var(--primary), var(--accent));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 8px;
}

.stat-item p {
    color: var(--gray-500);
    font-size: 14px;
    font-weight: 500;
}

/* ==================== Badges (关于我们) ==================== */
.badge {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    background: var(--primary-light);
    color: var(--primary);
    padding: 10px 20px;
    border-radius: var(--radius-full);
    font-size: 14px;
    font-weight: 600;
    transition: all var(--transition);
    border: 1px solid rgba(37, 99, 235, 0.15);
}

.badge:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.badge::before {
    content: '✦';
    font-size: 12px;
}

/* ==================== Case Cards (客户案例) ==================== */
.case-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
    gap: 30px;
}

.case-card {
    background: var(--white);
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow);
    transition: all var(--transition);
    border: 1px solid var(--gray-100);
}

.case-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-xl);
    border-color: transparent;
}

.case-card img {
    width: 100%;
    height: 220px;
    object-fit: cover;
    transition: transform 0.6s ease;
}

.case-card:hover img {
    transform: scale(1.05);
}

.case-info {
    padding: 28px;
}

.case-info h3 {
    color: var(--dark);
    margin-bottom: 10px;
    font-size: 19px;
    font-weight: 700;
}

.case-info p {
    color: var(--gray-500);
    font-size: 15px;
    line-height: 1.7;
}

/* ==================== Contact Cards (联系我们) ==================== */
.contact-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 28px;
}

.contact-card {
    background: var(--white);
    padding: 44px 32px;
    border-radius: var(--radius-lg);
    text-align: center;
    box-shadow: var(--shadow);
    transition: all var(--transition);
    border: 1px solid var(--gray-100);
}

.contact-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-xl);
    border-color: transparent;
}

.contact-icon {
    width: 72px;
    height: 72px;
    margin: 0 auto 20px;
    background: linear-gradient(135deg, var(--primary-light), var(--accent-light));
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 28px;
    color: var(--primary);
    transition: all var(--transition);
}

.contact-card:hover .contact-icon {
    background: linear-gradient(135deg, var(--primary), var(--accent));
    color: var(--white);
    transform: scale(1.05);
}

.contact-card h3 {
    color: var(--dark);
    font-size: 18px;
    font-weight: 700;
    margin-bottom: 10px;
}

.contact-card p {
    color: var(--gray-500);
    font-size: 15px;
    line-height: 1.6;
}

.contact-detail {
    font-size: 13px !important;
    color: var(--gray-400) !important;
    margin-top: 6px;
}

/* ==================== Footer ==================== */
.footer {
    background: var(--dark);
    color: var(--gray-300);
    position: relative;
}

.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr;
    gap: 60px;
}

.footer-brand .logo {
    font-size: 22px;
    margin-bottom: 12px;
    display: inline-block;
}

.footer-brand p {
    font-size: 14px;
    color: var(--gray-400);
    line-height: 1.8;
    max-width: 320px;
}

.footer-links h4 {
    color: var(--white);
    font-size: 16px;
    font-weight: 700;
    margin-bottom: 16px;
    letter-spacing: 0.5px;
}

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

.footer-links ul li {
    margin-bottom: 10px;
}

.footer-links ul li a {
    color: var(--gray-400);
    text-decoration: none;
    font-size: 14px;
    transition: all var(--transition);
    display: inline-flex;
    align-items: center;
    gap: 6px;
}

.footer-links ul li a:hover {
    color: var(--accent);
    transform: translateX(4px);
}

.footer-bottom {
    border-top: 1px solid var(--gray-700);
    padding: 24px 0;
    text-align: center;
}

.footer-bottom p {
    font-size: 13px;
    color: var(--gray-500);
    margin: 4px 0;
}

.footer-bottom a {
    color: var(--accent);
    text-decoration: none;
}

/* ==================== Back to Top ==================== */
.back-to-top {
    position: fixed;
    bottom: 32px;
    right: 32px;
    width: 46px;
    height: 46px;
    background: var(--primary);
    color: var(--white);
    border: none;
    border-radius: 50%;
    font-size: 18px;
    cursor: pointer;
    box-shadow: var(--shadow-lg);
    transition: all var(--transition);
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px);
    z-index: 999;
    display: flex;
    align-items: center;
    justify-content: center;
}

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

.back-to-top:hover {
    background: var(--primary-dark);
    transform: translateY(-4px);
    box-shadow: var(--shadow-xl);
}

/* ==================== Animations ==================== */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

.animate-on-scroll {
    opacity: 0;
    transform: translateY(30px);
    transition: all 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

.animate-on-scroll.visible {
    opacity: 1;
    transform: translateY(0);
}

/* ==================== Responsive ==================== */
@media (max-width: 1024px) {
    .footer-grid {
        grid-template-columns: 1fr 1fr;
        gap: 40px;
    }

    .about-preview .container {
        gap: 40px;
    }
}

@media (max-width: 768px) {
    .hero h1 {
        font-size: 32px;
    }

    .hero p {
        font-size: 16px;
    }

    .page-hero h1 {
        font-size: 30px;
    }

    .section-title {
        font-size: 28px;
    }

    .container {
        padding: 50px 0;
    }

    .about-preview .container {
        flex-direction: column;
        text-align: center;
    }

    .about-stats {
        width: 100%;
    }

    .footer-grid {
        grid-template-columns: 1fr;
        gap: 36px;
    }

    nav ul {
        gap: 2px;
    }

    nav ul li a {
        padding: 6px 12px;
        font-size: 13px;
    }

    .back-to-top {
        bottom: 20px;
        right: 20px;
        width: 40px;
        height: 40px;
        font-size: 16px;
    }
}