/* === 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", "Microsoft YaHei", sans-serif; line-height: 1.6; color: #333; background: #fff; }
a { text-decoration: none; color: inherit; transition: color 0.3s; }
ul { list-style: none; }
img { max-width: 100%; display: block; }
.container { max-width: 1200px; margin: 0 auto; padding: 0 20px; }
.section { padding: 80px 0; }
.section-title { text-align: center; font-size: 2rem; margin-bottom: 16px; color: #1a1a2e; }
.section-desc { text-align: center; color: #666; max-width: 700px; margin: 0 auto 40px; }

/* === Navbar === */
.navbar { position: fixed; top: 0; left: 0; right: 0; 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); padding: 0 0; height: 70px; display: flex; align-items: center; }
.nav-container { display: flex; align-items: center; justify-content: space-between; width: 100%; max-width: 1200px; margin: 0 auto; padding: 0 20px; }
.logo { display: flex; flex-direction: column; line-height: 1.2; }
.logo-zh { font-size: 1.3rem; font-weight: 700; color: #0d47a1; }
.logo-en { font-size: 0.65rem; color: #666; letter-spacing: 1px; text-transform: uppercase; }
.nav-links { display: flex; gap: 32px; }
.nav-links a { font-size: 0.95rem; font-weight: 500; color: #333; position: relative; padding: 4px 0; }
.nav-links a:hover, .nav-links a.active { color: #0d47a1; }
.nav-links a::after { content: ''; position: absolute; bottom: 0; left: 0; width: 0; height: 2px; background: #0d47a1; transition: width 0.3s; }
.nav-links a:hover::after { width: 100%; }
.lang-switch { background: #0d47a1; color: #fff; border: none; padding: 8px 18px; border-radius: 20px; cursor: pointer; font-size: 0.85rem; font-weight: 600; transition: background 0.3s; }
.lang-switch:hover { background: #1565c0; }
.mobile-menu-btn { display: none; background: none; border: none; font-size: 1.5rem; cursor: pointer; }

/* === Hero === */
.hero { position: relative; min-height: 100vh; display: flex; align-items: center; justify-content: center; background: linear-gradient(135deg, #0d47a1 0%, #1565c0 50%, #0a3d8f 100%); overflow: hidden; }
.hero-overlay { position: absolute; inset: 0; background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 1440 320"><path fill="rgba(255,255,255,0.05)" d="M0,96L48,112C96,128,192,160,288,186.7C384,213,480,235,576,213.3C672,192,768,128,864,128C960,128,1056,192,1152,208C1248,224,1344,192,1392,176L1440,160L1440,320L1392,320C1344,320,1248,320,1152,320C1056,320,960,320,864,320C768,320,672,320,576,320C480,320,384,320,288,320C192,320,96,320,48,320L0,320Z"/></svg>') no-repeat bottom center; background-size: cover; }
.hero-content { position: relative; text-align: center; color: #fff; padding: 0 20px; }
.hero-content h1 { font-size: 3.5rem; font-weight: 800; margin-bottom: 20px; text-shadow: 0 4px 30px rgba(0,0,0,0.3); }
.hero-content p { font-size: 1.3rem; opacity: 0.9; margin-bottom: 40px; }
.btn-primary { display: inline-block; padding: 16px 40px; background: #fff; color: #0d47a1; font-size: 1.1rem; font-weight: 700; border-radius: 30px; transition: all 0.3s; box-shadow: 0 4px 20px rgba(0,0,0,0.2); }
.btn-primary:hover { transform: translateY(-3px); box-shadow: 0 8px 30px rgba(0,0,0,0.3); background: #f0f4ff; }

/* === About === */
.about-section { background: #f8f9fc; }
.about-grid { display: grid; grid-template-columns: 1.2fr 0.8fr; gap: 60px; align-items: start; }
.about-text p { margin-bottom: 18px; color: #444; font-size: 1.05rem; line-height: 1.8; }
.about-stats { display: grid; grid-template-columns: 1fr 1fr; gap: 24px; }
.stat-item { background: #fff; padding: 30px; border-radius: 16px; text-align: center; box-shadow: 0 4px 20px rgba(0,0,0,0.06); transition: transform 0.3s; }
.stat-item:hover { transform: translateY(-5px); }
.stat-number { display: block; font-size: 2.5rem; font-weight: 800; color: #0d47a1; margin-bottom: 8px; }
.stat-number .unit { font-size: 1rem; font-weight: 600; }
.stat-label { font-size: 0.9rem; color: #666; }

/* === Products === */
.products-section { background: #fff; }
.product-categories { display: flex; justify-content: center; gap: 12px; margin-bottom: 40px; flex-wrap: wrap; }
.cat-btn { padding: 10px 28px; border: 2px solid #e0e0e0; background: #fff; border-radius: 25px; cursor: pointer; font-size: 0.95rem; font-weight: 500; transition: all 0.3s; color: #555; }
.cat-btn:hover, .cat-btn.active { border-color: #0d47a1; background: #0d47a1; color: #fff; }
.product-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(340px, 1fr)); gap: 30px; }
.product-card { background: #fff; border-radius: 16px; overflow: hidden; box-shadow: 0 4px 20px rgba(0,0,0,0.08); transition: all 0.3s; border: 1px solid #eee; }
.product-card:hover { transform: translateY(-8px); box-shadow: 0 12px 40px rgba(0,0,0,0.12); }
.product-img-placeholder { height: 200px; background: linear-gradient(135deg, #e3f2fd, #bbdefb); display: flex; align-items: center; justify-content: center; font-size: 1.2rem; font-weight: 700; color: #0d47a1; }
.product-info { padding: 24px; }
.product-info h3 { font-size: 1.15rem; margin-bottom: 8px; color: #1a1a2e; }
.product-spec { font-size: 0.85rem; color: #0d47a1; font-weight: 600; margin-bottom: 10px; }
.product-desc { font-size: 0.9rem; color: #666; line-height: 1.6; }

/* === Features === */
.features-section { background: #0d47a1; color: #fff; }
.features-section .section-title { color: #fff; }
.features-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(250px, 1fr)); gap: 30px; margin-top: 40px; }
.feature-card { background: rgba(255,255,255,0.1); padding: 36px 28px; border-radius: 16px; text-align: center; backdrop-filter: blur(10px); transition: transform 0.3s; }
.feature-card:hover { transform: translateY(-5px); background: rgba(255,255,255,0.15); }
.feature-icon { font-size: 2.5rem; margin-bottom: 16px; }
.feature-card h3 { font-size: 1.2rem; margin-bottom: 12px; }
.feature-card p { font-size: 0.9rem; opacity: 0.85; line-height: 1.6; }

/* === Contact === */
.contact-section { background: #f8f9fc; }
.contact-grid { max-width: 700px; margin: 0 auto; }
.contact-item { display: flex; align-items: flex-start; gap: 20px; padding: 24px; background: #fff; border-radius: 12px; margin-bottom: 16px; box-shadow: 0 2px 12px rgba(0,0,0,0.05); }
.contact-icon { font-size: 1.8rem; flex-shrink: 0; }
.contact-item strong { display: block; margin-bottom: 4px; color: #1a1a2e; }
.contact-item p { color: #555; font-size: 0.95rem; }

/* === Footer === */
.footer { background: #1a1a2e; color: rgba(255,255,255,0.7); text-align: center; padding: 30px 0; font-size: 0.85rem; }
.footer-slogan { margin-top: 8px; font-size: 0.9rem; opacity: 0.6; }

/* === Responsive === */
@media (max-width: 768px) {
    .nav-links { display: none; position: absolute; top: 70px; left: 0; right: 0; background: #fff; flex-direction: column; padding: 20px; gap: 16px; box-shadow: 0 10px 30px rgba(0,0,0,0.1); }
    .nav-links.open { display: flex; }
    .mobile-menu-btn { display: block; }
    .hero-content h1 { font-size: 2rem; }
    .hero-content p { font-size: 1rem; }
    .about-grid { grid-template-columns: 1fr; gap: 30px; }
    .product-grid { grid-template-columns: 1fr; }
    .section { padding: 50px 0; }
    .section-title { font-size: 1.6rem; }
}

/* Product image styles */
.product-img {
    width: 100%;
    height: 220px;
    overflow: hidden;
    background: #f5f5f5;
}
.product-img img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.3s ease;
}
.product-card:hover .product-img img {
    transform: scale(1.05);
}