/* ============================
   CSS Variables
   ============================ */
:root {
    --primary: #2563eb;
    --primary-dark: #1d4ed8;
    --primary-light: #3b82f6;
    --primary-bg: #eff6ff;
    --accent: #06b6d4;
    --dark: #0f172a;
    --dark-2: #1e293b;
    --dark-3: #334155;
    --gray: #64748b;
    --gray-light: #94a3b8;
    --gray-lighter: #cbd5e1;
    --border: #e2e8f0;
    --bg: #ffffff;
    --bg-alt: #f8fafc;
    --bg-section: #f1f5f9;
    --radius: 12px;
    --radius-sm: 8px;
    --radius-lg: 20px;
    --shadow: 0 1px 3px rgba(0,0,0,0.08), 0 1px 2px rgba(0,0,0,0.06);
    --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.08), 0 2px 4px -2px rgba(0,0,0,0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.08), 0 4px 6px -4px rgba(0,0,0,0.06);
    --shadow-xl: 0 20px 25px -5px rgba(0,0,0,0.1), 0 8px 10px -6px rgba(0,0,0,0.08);
    --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --max-width: 1200px;
}

/* ============================
   Reset & Base
   ============================ */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
    font-size: 16px;
    line-height: 1.6;
    color: var(--dark);
    background: var(--bg);
    overflow-x: hidden;
}

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

ul { list-style: none; }

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

.container {
    width: 100%;
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 24px;
}

/* ============================
   Buttons
   ============================ */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 14px 32px;
    border-radius: var(--radius-sm);
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    border: 2px solid transparent;
    transition: all var(--transition);
    white-space: nowrap;
}

.btn-primary {
    background: var(--primary);
    color: #fff;
    border-color: var(--primary);
}
.btn-primary:hover {
    background: var(--primary-dark);
    border-color: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(37, 99, 235, 0.4);
}

.btn-outline {
    background: transparent;
    color: #fff;
    border-color: rgba(255,255,255,0.5);
}
.btn-outline:hover {
    background: #fff;
    color: var(--primary);
    border-color: #fff;
    transform: translateY(-2px);
}

.btn-block {
    width: 100%;
}

/* ============================
   Navbar
   ============================ */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: transparent;
    transition: all var(--transition);
}

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

.navbar-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 80px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
}

.logo-icon {
    font-size: 28px;
    color: var(--primary-light);
}

.logo-text {
    font-size: 20px;
    font-weight: 700;
    color: #fff;
    display: flex;
    flex-direction: column;
    line-height: 1.2;
}

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

.logo-sub {
    font-size: 10px;
    font-weight: 500;
    letter-spacing: 2px;
    opacity: 0.7;
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 8px;
}

.nav-link {
    padding: 8px 16px;
    font-size: 15px;
    font-weight: 500;
    color: rgba(255,255,255,0.85);
    border-radius: 6px;
    transition: all var(--transition);
}
.nav-link:hover,
.nav-link.active {
    color: #fff;
    background: rgba(255,255,255,0.15);
}

.navbar.scrolled .nav-link {
    color: var(--gray);
}
.navbar.scrolled .nav-link:hover,
.navbar.scrolled .nav-link.active {
    color: var(--primary);
    background: var(--primary-bg);
}

.mobile-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    padding: 8px;
    background: none;
    border: none;
    cursor: pointer;
}
.mobile-toggle span {
    display: block;
    width: 24px;
    height: 2px;
    background: #fff;
    border-radius: 2px;
    transition: all var(--transition);
}
.navbar.scrolled .mobile-toggle span { background: var(--dark); }

/* ============================
   Hero
   ============================ */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, rgba(15,23,42,0.85) 0%, rgba(30,58,95,0.8) 40%, rgba(29,78,216,0.75) 100%),
                url('https://images.unsplash.com/photo-1451187580459-43490279c0fa?w=1920&q=80') center/cover no-repeat;
    overflow: hidden;
    padding: 120px 0 80px;
}

.hero-bg {
    position: absolute;
    inset: 0;
    overflow: hidden;
}

.hero-particle {
    position: absolute;
    border-radius: 50%;
    opacity: 0.08;
    background: #fff;
    animation: float 20s infinite ease-in-out;
}
.hero-particle:nth-child(1) { width: 400px; height: 400px; top: -100px; right: -100px; animation-delay: 0s; }
.hero-particle:nth-child(2) { width: 300px; height: 300px; bottom: -80px; left: -80px; animation-delay: -5s; }
.hero-particle:nth-child(3) { width: 200px; height: 200px; top: 40%; left: 30%; animation-delay: -10s; }
.hero-particle:nth-child(4) { width: 150px; height: 150px; top: 20%; right: 20%; animation-delay: -7s; }
.hero-particle:nth-child(5) { width: 100px; height: 100px; bottom: 20%; right: 30%; animation-delay: -3s; }

@keyframes float {
    0%, 100% { transform: translate(0, 0) scale(1); }
    25% { transform: translate(30px, -30px) scale(1.05); }
    50% { transform: translate(-20px, 20px) scale(0.95); }
    75% { transform: translate(15px, 10px) scale(1.02); }
}

.hero-content {
    position: relative;
    z-index: 1;
    text-align: center;
    color: #fff;
}

.hero-title {
    font-size: 56px;
    font-weight: 800;
    line-height: 1.2;
    margin-bottom: 24px;
}

.hero-line1 {
    display: block;
    font-size: 0.6em;
    font-weight: 600;
    opacity: 0.85;
    margin-bottom: 8px;
}

.hero-line2 {
    display: block;
    background: linear-gradient(90deg, #fff 0%, #93c5fd 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-desc {
    font-size: 18px;
    line-height: 1.8;
    max-width: 640px;
    margin: 0 auto 40px;
    color: rgba(255,255,255,0.75);
}

.hero-actions {
    display: flex;
    gap: 16px;
    justify-content: center;
    margin-bottom: 64px;
}

.hero-stats {
    display: flex;
    justify-content: center;
    gap: 48px;
}

.stat-item {
    text-align: center;
}

.stat-num {
    display: block;
    font-size: 40px;
    font-weight: 800;
    line-height: 1;
    color: #fff;
}

.stat-plus {
    font-size: 24px;
    font-weight: 700;
    color: var(--accent);
}

.stat-label {
    display: block;
    margin-top: 8px;
    font-size: 14px;
    color: rgba(255,255,255,0.6);
}

.scroll-down {
    position: absolute;
    bottom: 32px;
    left: 50%;
    transform: translateX(-50%);
    color: rgba(255,255,255,0.5);
    font-size: 20px;
    animation: bounce 2s infinite;
}

@keyframes bounce {
    0%, 100% { transform: translateX(-50%) translateY(0); }
    50% { transform: translateX(-50%) translateY(10px); }
}

/* ============================
   Sections Common
   ============================ */
.section {
    padding: 100px 0;
}

.section:nth-child(even) {
    background: var(--bg-section);
}

.section-header {
    text-align: center;
    margin-bottom: 64px;
}

.section-tag {
    display: inline-block;
    font-size: 13px;
    font-weight: 700;
    letter-spacing: 3px;
    color: var(--primary);
    text-transform: uppercase;
    margin-bottom: 12px;
}

.section-title {
    font-size: 36px;
    font-weight: 800;
    color: var(--dark);
    margin-bottom: 16px;
}

.section-desc {
    font-size: 17px;
    color: var(--gray);
    max-width: 500px;
    margin: 0 auto;
}

/* ============================
   About
   ============================ */
.about-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 64px;
    align-items: center;
}

.about-text h3 {
    font-size: 24px;
    font-weight: 700;
    margin-bottom: 20px;
    color: var(--dark);
}

.about-text p {
    font-size: 15px;
    line-height: 1.8;
    color: var(--gray);
    margin-bottom: 16px;
}

.about-features {
    display: flex;
    flex-direction: column;
    gap: 16px;
    margin-top: 32px;
}

.about-feat {
    display: flex;
    align-items: center;
    gap: 16px;
    padding: 16px 20px;
    background: var(--bg-alt);
    border-radius: var(--radius-sm);
    transition: all var(--transition);
}
.about-feat:hover {
    background: var(--primary-bg);
    transform: translateX(4px);
}

.about-feat i {
    font-size: 20px;
    color: var(--primary);
    width: 24px;
    text-align: center;
    flex-shrink: 0;
}

.about-feat strong {
    display: block;
    font-size: 15px;
    font-weight: 600;
    color: var(--dark);
    margin-bottom: 2px;
}

.about-feat span {
    font-size: 13px;
    color: var(--gray);
}

.about-visual {
    display: flex;
    justify-content: center;
}

.about-image {
    position: relative;
    border-radius: var(--radius-lg);
    overflow: hidden;
    width: 100%;
    max-width: 480px;
    box-shadow: var(--shadow-xl);
}

.about-image img {
    width: 100%;
    height: 380px;
    object-fit: cover;
    display: block;
}

.about-image-overlay {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    padding: 24px;
    background: linear-gradient(to top, rgba(37,99,235,0.9) 0%, transparent 100%);
}

.about-icon-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 12px;
}

.icon-box {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 52px;
    height: 52px;
    background: rgba(255,255,255,0.2);
    backdrop-filter: blur(8px);
    border-radius: var(--radius-sm);
    font-size: 20px;
    color: #fff;
    transition: all var(--transition);
}
.icon-box:hover {
    background: rgba(255,255,255,0.35);
    transform: scale(1.1);
}

/* ============================
   Services
   ============================ */
.services-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
}

.service-card {
    position: relative;
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 36px 28px;
    transition: all var(--transition);
}
.service-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-xl);
    border-color: transparent;
}

.service-card.featured {
    background: linear-gradient(135deg, var(--primary) 0%, #1d4ed8 100%);
    color: #fff;
    border-color: transparent;
    box-shadow: var(--shadow-lg);
}
.service-card.featured .service-icon { background: rgba(255,255,255,0.2); color: #fff; }
.service-card.featured p { color: rgba(255,255,255,0.8); }
.service-card.featured .service-list li { color: rgba(255,255,255,0.85); }
.service-card.featured .service-list li::before { color: rgba(255,255,255,0.6); }

.service-badge {
    position: absolute;
    top: 16px;
    right: 16px;
    background: #fbbf24;
    color: var(--dark);
    font-size: 12px;
    font-weight: 700;
    padding: 4px 12px;
    border-radius: 20px;
}

.service-icon {
    width: 60px;
    height: 60px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--primary-bg);
    border-radius: var(--radius-sm);
    color: var(--primary);
    font-size: 24px;
    margin-bottom: 20px;
}

.service-card h3 {
    font-size: 19px;
    font-weight: 700;
    margin-bottom: 12px;
}

.service-card p {
    font-size: 14px;
    line-height: 1.7;
    color: var(--gray);
    margin-bottom: 16px;
}

.service-list {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.service-list li {
    font-size: 13px;
    color: var(--dark-3);
    padding-left: 16px;
    position: relative;
}
.service-list li::before {
    content: "\f00c";
    font-family: "Font Awesome 6 Free";
    font-weight: 900;
    font-size: 10px;
    position: absolute;
    left: 0;
    color: var(--primary);
}

/* ============================
   Advantages
   ============================ */
.advantages-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 24px;
}

.adv-card {
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 36px 28px;
    text-align: center;
    transition: all var(--transition);
    position: relative;
    overflow: hidden;
}
.adv-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: var(--primary);
    transform: scaleX(0);
    transition: transform var(--transition);
}
.adv-card:hover::before { transform: scaleX(1); }

.adv-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-xl);
    border-color: transparent;
}

.adv-num {
    font-size: 48px;
    font-weight: 900;
    color: var(--primary-bg);
    line-height: 1;
    margin-bottom: 12px;
}
.adv-card:hover .adv-num { color: var(--primary); opacity: 0.2; }

.adv-icon {
    width: 56px;
    height: 56px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--primary-bg);
    border-radius: 50%;
    color: var(--primary);
    font-size: 22px;
    margin: 0 auto 20px;
    transition: all var(--transition);
}
.adv-card:hover .adv-icon {
    background: var(--primary);
    color: #fff;
    transform: scale(1.1);
}

.adv-card h3 {
    font-size: 18px;
    font-weight: 700;
    margin-bottom: 12px;
    color: var(--dark);
}

.adv-card p {
    font-size: 14px;
    line-height: 1.7;
    color: var(--gray);
}

/* ============================
   Cases
   ============================ */
.cases-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 28px;
}

.case-card {
    background: var(--bg);
    border-radius: var(--radius);
    overflow: hidden;
    border: 1px solid var(--border);
    transition: all var(--transition);
}
.case-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-xl);
    border-color: transparent;
}

.case-cover {
    position: relative;
    height: 200px;
    overflow: hidden;
}

.case-cover img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.5s ease;
}
.case-card:hover .case-cover img {
    transform: scale(1.08);
}

.case-overlay {
    position: absolute;
    top: 16px;
    left: 16px;
}

.case-tag {
    display: inline-block;
    background: rgba(255,255,255,0.2);
    backdrop-filter: blur(10px);
    color: #fff;
    font-size: 12px;
    font-weight: 600;
    padding: 4px 14px;
    border-radius: 20px;
}

.case-info {
    padding: 24px;
}

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

.case-info p {
    font-size: 14px;
    line-height: 1.7;
    color: var(--gray);
    margin-bottom: 16px;
}

.case-techs {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.case-techs span {
    font-size: 12px;
    color: var(--primary);
    background: var(--primary-bg);
    padding: 4px 12px;
    border-radius: 20px;
    font-weight: 500;
}

/* ============================
   Contact
   ============================ */
.contact-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 64px;
    align-items: start;
}

.contact-info-list {
    display: flex;
    flex-direction: column;
    gap: 28px;
}

.contact-item {
    display: flex;
    align-items: flex-start;
    gap: 16px;
}

.contact-icon {
    width: 48px;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--primary-bg);
    border-radius: var(--radius-sm);
    color: var(--primary);
    font-size: 18px;
    flex-shrink: 0;
}

.contact-item h4 {
    font-size: 15px;
    font-weight: 600;
    color: var(--dark);
    margin-bottom: 4px;
}

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

.contact-social h4 {
    font-size: 15px;
    font-weight: 600;
    color: var(--dark);
    margin-bottom: 12px;
}

.social-links {
    display: flex;
    gap: 12px;
}

.social-links a {
    width: 44px;
    height: 44px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--bg-alt);
    border: 1px solid var(--border);
    border-radius: 50%;
    color: var(--gray);
    font-size: 18px;
    transition: all var(--transition);
}
.social-links a:hover {
    background: var(--primary);
    border-color: var(--primary);
    color: #fff;
    transform: translateY(-3px);
}

.contact-form-wrap {
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 36px;
    box-shadow: var(--shadow);
}

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
}

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    font-size: 14px;
    font-weight: 600;
    color: var(--dark);
    margin-bottom: 8px;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 12px 16px;
    font-size: 14px;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    background: var(--bg-alt);
    color: var(--dark);
    transition: all var(--transition);
    font-family: inherit;
    outline: none;
}
.form-group input:focus,
.form-group textarea:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
    background: var(--bg);
}

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

/* ============================
   Footer
   ============================ */
.footer {
    background: var(--dark);
    color: rgba(255,255,255,0.7);
    padding: 60px 0 0;
}

.footer-top {
    display: flex;
    justify-content: space-between;
    gap: 64px;
    padding-bottom: 40px;
    border-bottom: 1px solid rgba(255,255,255,0.1);
}

.footer-brand .logo-text { color: #fff; }
.footer-brand p {
    font-size: 14px;
    line-height: 1.7;
    margin-top: 16px;
    color: rgba(255,255,255,0.5);
}

.footer-links {
    display: flex;
    gap: 64px;
}

.footer-col h4 {
    font-size: 15px;
    font-weight: 600;
    color: #fff;
    margin-bottom: 20px;
}

.footer-col a {
    display: block;
    font-size: 14px;
    color: rgba(255,255,255,0.5);
    margin-bottom: 12px;
    transition: color var(--transition);
}
.footer-col a:hover {
    color: #fff;
}

.footer-bottom {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 24px 0;
    font-size: 13px;
    color: rgba(255,255,255,0.35);
}

.footer-bottom a {
    color: rgba(255,255,255,0.35);
}
.footer-bottom a:hover {
    color: rgba(255,255,255,0.7);
}

/* ============================
   Back to Top
   ============================ */
.back-top {
    position: fixed;
    bottom: 32px;
    right: 32px;
    width: 48px;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--primary);
    color: #fff;
    border: none;
    border-radius: 50%;
    font-size: 18px;
    cursor: pointer;
    box-shadow: var(--shadow-lg);
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px);
    transition: all var(--transition);
    z-index: 999;
}
.back-top.visible {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}
.back-top:hover {
    background: var(--primary-dark);
    transform: translateY(-3px);
}

/* ============================
   Scroll Animations
   ============================ */
.fade-up {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}
.fade-up.visible {
    opacity: 1;
    transform: translateY(0);
}

/* ============================
   Responsive
   ============================ */
@media (max-width: 1024px) {
    .hero-title { font-size: 44px; }
    .services-grid { grid-template-columns: repeat(2, 1fr); }
    .advantages-grid { grid-template-columns: repeat(2, 1fr); }
    .cases-grid { grid-template-columns: repeat(2, 1fr); }
    .about-grid { gap: 40px; }
}

@media (max-width: 768px) {
    .mobile-toggle { display: flex; }

    .nav-links {
        display: none;
        position: absolute;
        top: 80px;
        left: 0;
        right: 0;
        background: rgba(255,255,255,0.98);
        backdrop-filter: blur(20px);
        flex-direction: column;
        padding: 16px 24px;
        gap: 4px;
        box-shadow: var(--shadow-lg);
    }
    .nav-links.open { display: flex; }
    .nav-links .nav-link {
        color: var(--dark);
        padding: 12px 16px;
        width: 100%;
    }
    .nav-links .nav-link:hover,
    .nav-links .nav-link.active {
        color: var(--primary);
        background: var(--primary-bg);
    }

    .hero { padding: 100px 0 60px; }
    .hero-title { font-size: 32px; }
    .hero-desc { font-size: 15px; }
    .hero-actions { flex-direction: column; align-items: center; }
    .hero-stats { flex-wrap: wrap; gap: 24px; }
    .stat-num { font-size: 32px; }

    .section { padding: 64px 0; }
    .section-title { font-size: 28px; }
    .section-header { margin-bottom: 40px; }

    .about-grid { grid-template-columns: 1fr; }
    .services-grid { grid-template-columns: 1fr; }
    .advantages-grid { grid-template-columns: 1fr; }
    .cases-grid { grid-template-columns: 1fr; }
    .contact-grid { grid-template-columns: 1fr; }
    .form-row { grid-template-columns: 1fr; }

    .footer-top { flex-direction: column; gap: 32px; }
    .footer-links { gap: 40px; }
    .footer-bottom { flex-direction: column; gap: 8px; text-align: center; }
}

@media (max-width: 480px) {
    .container { padding: 0 16px; }
    .hero-title { font-size: 28px; }
    .hero-stats { gap: 16px; }
    .stat-item { min-width: 80px; }
    .contact-form-wrap { padding: 24px; }
    .footer-links { flex-direction: column; gap: 24px; }
}