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

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #fff;
}

a {
    text-decoration: none;
    color: inherit;
    transition: color 0.3s ease;
}

ul {
    list-style: none;
}

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

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* ===== Header & Navigation ===== */
.header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    box-shadow: 0 2px 20px rgba(0, 0, 0, 0.08);
    transition: all 0.3s ease;
}

.header.scrolled {
    background: rgba(255, 255, 255, 0.98);
    box-shadow: 0 2px 30px rgba(0, 0, 0, 0.12);
}

.nav-wrapper {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 70px;
}

.logo {
    display: flex;
    align-items: baseline;
    gap: 8px;
}

.logo-text {
    font-size: 1.5rem;
    font-weight: 700;
    color: #1a56db;
    letter-spacing: 2px;
}

.logo-sub {
    font-size: 0.7rem;
    color: #6b7280;
    letter-spacing: 1px;
    text-transform: uppercase;
}

.nav-list {
    display: flex;
    gap: 32px;
}

.nav-link {
    font-size: 0.95rem;
    font-weight: 500;
    color: #4b5563;
    padding: 8px 0;
    position: relative;
    transition: color 0.3s ease;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: #1a56db;
    transition: width 0.3s ease;
}

.nav-link:hover,
.nav-link.active {
    color: #1a56db;
}

.nav-link:hover::after,
.nav-link.active::after {
    width: 100%;
}

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 5px;
}

.nav-toggle span {
    width: 24px;
    height: 2px;
    background: #333;
    transition: all 0.3s ease;
}

/* ===== Banner ===== */
.banner {
    position: relative;
    height: 100vh;
    min-height: 600px;
    display: flex;
    align-items: center;
    background: linear-gradient(135deg, #0f172a 0%, #1e3a5f 50%, #1a56db 100%);
    overflow: hidden;
}

.banner::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: 
        radial-gradient(ellipse at 20% 50%, rgba(26, 86, 219, 0.3) 0%, transparent 50%),
        radial-gradient(ellipse at 80% 20%, rgba(59, 130, 246, 0.2) 0%, transparent 50%),
        radial-gradient(ellipse at 60% 80%, rgba(37, 99, 235, 0.15) 0%, transparent 50%);
}

.banner-overlay {
    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="10" height="10" patternUnits="userSpaceOnUse"><path d="M 10 0 L 0 0 0 10" fill="none" stroke="rgba(255,255,255,0.03)" stroke-width="0.5"/></pattern></defs><rect width="100" height="100" fill="url(%23grid)"/></svg>');
}

.banner-content {
    position: relative;
    z-index: 2;
    text-align: center;
    color: #fff;
}

.banner-title {
    font-size: 3.5rem;
    font-weight: 700;
    margin-bottom: 16px;
    letter-spacing: 4px;
    text-shadow: 0 2px 20px rgba(0, 0, 0, 0.3);
}

.banner-subtitle {
    font-size: 1.25rem;
    opacity: 0.9;
    margin-bottom: 48px;
    letter-spacing: 2px;
}

.banner-stats {
    display: flex;
    justify-content: center;
    gap: 60px;
    margin-bottom: 48px;
}

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

.stat-number {
    font-size: 2.5rem;
    font-weight: 700;
    color: #60a5fa;
}

.stat-plus {
    font-size: 1.5rem;
    color: #60a5fa;
}

.stat-label {
    display: block;
    font-size: 0.9rem;
    opacity: 0.8;
    margin-top: 4px;
}

/* ===== Buttons ===== */
.btn {
    display: inline-block;
    padding: 14px 36px;
    border-radius: 6px;
    font-size: 1rem;
    font-weight: 500;
    transition: all 0.3s ease;
    cursor: pointer;
    border: none;
}

.btn-primary {
    background: #1a56db;
    color: #fff;
    box-shadow: 0 4px 15px rgba(26, 86, 219, 0.4);
}

.btn-primary:hover {
    background: #1e40af;
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(26, 86, 219, 0.5);
}

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

.section-header {
    text-align: center;
    margin-bottom: 60px;
}

.section-title {
    font-size: 2.2rem;
    font-weight: 700;
    color: #1f2937;
    margin-bottom: 8px;
}

.section-desc {
    font-size: 0.9rem;
    color: #9ca3af;
    text-transform: uppercase;
    letter-spacing: 2px;
}

/* ===== About ===== */
.about {
    background: #f9fafb;
}

.about-text {
    max-width: 800px;
    margin: 0 auto 50px;
    text-align: center;
}

.about-text p {
    margin-bottom: 16px;
    color: #4b5563;
    line-height: 1.8;
}

.about-features {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
}

.feature-item {
    text-align: center;
    padding: 40px 20px;
    background: #fff;
    border-radius: 12px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.05);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.feature-item:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 30px rgba(0, 0, 0, 0.1);
}

.feature-icon {
    font-size: 2.5rem;
    margin-bottom: 16px;
}

.feature-item h3 {
    font-size: 1.1rem;
    color: #1f2937;
    margin-bottom: 8px;
}

.feature-item p {
    font-size: 0.9rem;
    color: #6b7280;
}

/* ===== Services ===== */
.services-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
}

.service-card {
    padding: 40px 30px;
    background: #fff;
    border-radius: 12px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.05);
    border: 1px solid #f3f4f6;
    transition: all 0.3s ease;
}

.service-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 12px 40px rgba(26, 86, 219, 0.1);
    border-color: #dbeafe;
}

.service-icon {
    font-size: 2.5rem;
    margin-bottom: 20px;
}

.service-title {
    font-size: 1.2rem;
    color: #1f2937;
    margin-bottom: 12px;
}

.service-desc {
    font-size: 0.9rem;
    color: #6b7280;
    line-height: 1.7;
}

/* ===== Advantages ===== */
.advantages {
    background: linear-gradient(135deg, #0f172a 0%, #1e3a5f 100%);
    color: #fff;
}

.advantages .section-title {
    color: #fff;
}

.advantages .section-desc {
    color: rgba(255, 255, 255, 0.6);
}

.advantages-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 30px;
}

.advantage-item {
    padding: 30px;
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 12px;
    background: rgba(255, 255, 255, 0.05);
    transition: all 0.3s ease;
}

.advantage-item:hover {
    background: rgba(255, 255, 255, 0.1);
    border-color: rgba(96, 165, 250, 0.3);
}

.advantage-number {
    font-size: 2rem;
    font-weight: 700;
    color: #60a5fa;
    margin-bottom: 16px;
}

.advantage-item h3 {
    font-size: 1.1rem;
    margin-bottom: 12px;
}

.advantage-item p {
    font-size: 0.85rem;
    color: rgba(255, 255, 255, 0.7);
    line-height: 1.7;
}

/* ===== Contact ===== */
.contact {
    background: #f9fafb;
}

.contact-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 40px;
    align-items: center;
}

.contact-item {
    display: flex;
    align-items: flex-start;
    gap: 16px;
    padding: 20px;
    background: #fff;
    border-radius: 10px;
    margin-bottom: 16px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.04);
}

.contact-icon {
    font-size: 1.5rem;
    flex-shrink: 0;
}

.contact-detail h4 {
    font-size: 0.95rem;
    color: #1f2937;
    margin-bottom: 4px;
}

.contact-detail p {
    font-size: 0.9rem;
    color: #6b7280;
}

.map-placeholder {
    background: linear-gradient(135deg, #dbeafe, #eff6ff);
    border-radius: 12px;
    height: 300px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    border: 2px dashed #93c5fd;
}

.map-placeholder p {
    font-size: 3rem;
    margin-bottom: 10px;
}

.map-placeholder span {
    color: #6b7280;
    font-size: 0.9rem;
}

/* ===== Footer ===== */
.footer {
    background: #0f172a;
    color: #fff;
    padding: 60px 0 0;
}

.footer-content {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr;
    gap: 40px;
    padding-bottom: 40px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.footer-brand h3 {
    font-size: 1.3rem;
    margin-bottom: 8px;
}

.footer-brand p {
    color: rgba(255, 255, 255, 0.6);
    font-size: 0.9rem;
}

.footer-links h4,
.footer-contact h4 {
    font-size: 1rem;
    margin-bottom: 16px;
}

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

.footer-links ul li a {
    color: rgba(255, 255, 255, 0.6);
    font-size: 0.9rem;
    transition: color 0.3s ease;
}

.footer-links ul li a:hover {
    color: #60a5fa;
}

.footer-contact p {
    color: rgba(255, 255, 255, 0.6);
    font-size: 0.85rem;
    margin-bottom: 8px;
}

.footer-bottom {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 0;
    font-size: 0.85rem;
    color: rgba(255, 255, 255, 0.5);
}

.footer-bottom a {
    color: rgba(255, 255, 255, 0.5);
    transition: color 0.3s ease;
}

.footer-bottom a:hover {
    color: #60a5fa;
}

/* ===== Back to Top ===== */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 44px;
    height: 44px;
    background: #1a56db;
    color: #fff;
    border: none;
    border-radius: 50%;
    font-size: 1.2rem;
    cursor: pointer;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(26, 86, 219, 0.4);
    z-index: 999;
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
}

.back-to-top:hover {
    background: #1e40af;
    transform: translateY(-3px);
}

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

.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

/* ===== Responsive ===== */
@media (max-width: 1024px) {
    .advantages-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .services-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 768px) {
    .nav-toggle {
        display: flex;
    }
    
    .nav {
        position: fixed;
        top: 70px;
        left: 0;
        width: 100%;
        background: #fff;
        box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
        padding: 20px;
        transform: translateY(-100%);
        opacity: 0;
        visibility: hidden;
        transition: all 0.3s ease;
    }
    
    .nav.active {
        transform: translateY(0);
        opacity: 1;
        visibility: visible;
    }
    
    .nav-list {
        flex-direction: column;
        gap: 16px;
    }
    
    .banner-title {
        font-size: 2rem;
    }
    
    .banner-subtitle {
        font-size: 1rem;
    }
    
    .banner-stats {
        flex-direction: column;
        gap: 24px;
    }
    
    .stat-number {
        font-size: 2rem;
    }
    
    .about-features {
        grid-template-columns: 1fr;
    }
    
    .services-grid {
        grid-template-columns: 1fr;
    }
    
    .advantages-grid {
        grid-template-columns: 1fr;
    }
    
    .contact-grid {
        grid-template-columns: 1fr;
    }
    
    .footer-content {
        grid-template-columns: 1fr;
        gap: 30px;
    }
    
    .footer-bottom {
        flex-direction: column;
        gap: 8px;
        text-align: center;
    }
    
    .section {
        padding: 60px 0;
    }
    
    .section-title {
        font-size: 1.8rem;
    }
}

@media (max-width: 480px) {
    .banner-title {
        font-size: 1.6rem;
        letter-spacing: 2px;
    }
    
    .logo-text {
        font-size: 1.2rem;
    }
    
    .logo-sub {
        display: none;
    }
}