/* ========== CSS Variables ========== */
:root {
    --primary: #1a5276;
    --primary-light: #2980b9;
    --accent: #e74c3c;
    --accent-light: #ecf0f1;
    --text: #2c3e50;
    --text-light: #7f8c8d;
    --white: #ffffff;
    --bg-light: #f8f9fa;
    --bg-dark: #1a1a2e;
    --shadow: 0 4px 20px rgba(0,0,0,0.08);
    --transition: all 0.3s ease;
}

/* ========== Reset & Base ========== */
* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
    font-family: -apple-system, "Microsoft YaHei", "PingFang SC", sans-serif;
    color: var(--text);
    line-height: 1.6;
    background: var(--white);
}
a { text-decoration: none; color: inherit; }
ul { list-style: none; }
img { max-width: 100%; height: auto; }

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

.section { padding: 80px 0; }

.section-tag {
    display: inline-block;
    background: var(--primary);
    color: var(--white);
    padding: 4px 16px;
    border-radius: 20px;
    font-size: 0.85rem;
    margin-bottom: 12px;
}
.section-title {
    font-size: 2.2rem;
    margin-bottom: 16px;
    color: var(--primary);
}
.section-subtitle {
    font-size: 1.1rem;
    color: var(--text-light);
    max-width: 600px;
    margin: 0 auto 48px;
}

/* ========== Navigation ========== */
.navbar {
    position: fixed; top: 0; left: 0; right: 0;
    background: rgba(255,255,255,0.97);
    backdrop-filter: blur(10px);
    box-shadow: 0 2px 20px rgba(0,0,0,0.06);
    z-index: 1000;
    transition: var(--transition);
}
.nav-container {
    max-width: 1200px; margin: 0 auto;
    padding: 0 20px;
    display: flex; align-items: center; justify-content: space-between;
    height: 70px;
}
.nav-logo { display: flex; align-items: center; gap: 10px; font-size: 1.3rem; font-weight: 700; color: var(--primary); }
.logo-icon { font-size: 1.8rem; }
.lang-switch { display: flex; align-items: center; gap: 6px; font-size: 0.85rem; font-weight: 600; margin-left: auto; margin-right: 20px; }
.lang-btn { padding: 4px 10px; border-radius: 6px; transition: var(--transition); color: var(--text-light); }
.lang-btn:hover { color: var(--primary); background: rgba(26,82,118,0.08); }
.lang-btn.active { color: var(--primary); background: var(--primary); color: #fff; }
.lang-sep { color: #ccc; }
.nav-menu { display: flex; gap: 32px; }
.nav-menu a {
    font-size: 0.95rem; font-weight: 500;
    color: var(--text);
    position: relative;
    padding: 4px 0;
    transition: var(--transition);
}
.nav-menu a::after {
    content: '';
    position: absolute; bottom: 0; left: 0;
    width: 0; height: 2px;
    background: var(--primary);
    transition: width 0.3s ease;
}
.nav-menu a:hover::after { width: 100%; }
.nav-toggle { display: none; flex-direction: column; gap: 5px; background: none; border: none; cursor: pointer; padding: 5px; }
.nav-toggle span { display: block; width: 24px; height: 2px; background: var(--text); border-radius: 2px; transition: var(--transition); }

@media (max-width: 768px) {
    .lang-switch { margin: 10px 20px 0; justify-content: center; }
    .nav-menu {
        position: fixed; top: 70px; left: 0; right: 0;
        background: var(--white);
        flex-direction: column;
        padding: 20px;
        gap: 16px;
        transform: translateY(-100%);
        opacity: 0;
        pointer-events: none;
        transition: var(--transition);
        box-shadow: var(--shadow);
    }
    .nav-menu.active { transform: translateY(0); opacity: 1; pointer-events: all; }
    .nav-toggle { display: flex; }
}

/* ========== Hero ========== */
.hero {
    min-height: 100vh;
    display: flex; align-items: center; justify-content: center;
    background: url('assets/images/hero-bg.png') center center / cover no-repeat;
    color: var(--white);
    position: relative;
    overflow: hidden;
    padding-top: 70px;
}
.hero-overlay {
    position: absolute; inset: 0;
    background: linear-gradient(
        135deg, 
        rgba(10, 10, 15, 0.55) 0%, 
        rgba(26, 42, 68, 0.45) 40%,
        rgba(10, 10, 15, 0.60) 100%
    );
    z-index: 1;
}
.hero-bg { display: none; }
.hero-content {
    position: relative;
    z-index: 2;
    text-align: center;
    padding: 0 20px;
    max-width: 900px;
}
.hero-brand {
    margin-bottom: 40px;
}
.brand-tag {
    display: inline-block;
    background: rgba(255,255,255,0.1);
    border: 1px solid rgba(255,255,255,0.2);
    padding: 6px 20px;
    border-radius: 30px;
    font-size: 0.8rem;
    color: rgba(255,255,255,0.7);
    margin-bottom: 16px;
    letter-spacing: 2px;
}
.brand-slogan {
    font-size: 2.2rem;
    font-weight: 700;
    color: #fff;
    margin-bottom: 10px;
    letter-spacing: 6px;
}
.brand-meaning {
    font-size: 0.95rem;
    color: rgba(255,255,255,0.5);
    font-style: italic;
}
.hero-main {
    margin-bottom: 40px;
}
.hero-main h1 {
    font-size: 3.2rem;
    font-weight: 800;
    line-height: 1.2;
    margin-bottom: 16px;
    color: #fff;
    letter-spacing: 1px;
}
.hero-desc {
    font-size: 1.1rem;
    color: rgba(255,255,255,0.6);
    margin-bottom: 0;
}
.highlight {
    color: #e74c3c;
    background: linear-gradient(135deg, #e74c3c, #ff7675);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}
.hero-btns { display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; }
.btn {
    display: inline-block;
    padding: 14px 36px;
    border-radius: 50px;
    font-size: 1rem;
    font-weight: 600;
    transition: var(--transition);
    cursor: pointer;
    border: 2px solid transparent;
}
.btn-primary { background: #e74c3c; color: #fff; border-color: #e74c3c; }
.btn-primary:hover { background: transparent; color: #e74c3c; }
.btn-outline { background: transparent; color: #fff; border-color: rgba(255,255,255,0.4); }
.btn-outline:hover { background: rgba(255,255,255,0.1); border-color: #fff; }

@media (max-width: 768px) {
    .hero-main h1 { font-size: 2rem; }
    .brand-slogan { font-size: 1.6rem; letter-spacing: 3px; }
    .hero-desc { font-size: 0.95rem; }
}

/* ========== Products ========== */
#products {
    background: linear-gradient(180deg, #f8f9fa 0%, #e8f4fc 100%);
    position: relative;
}
#products::before {
    content: '';
    position: absolute;
    top: 0; right: 0;
    width: 50%;
    height: 100%;
    background: url('assets/images/products-showcase.png') center/cover;
    opacity: 0.1;
    pointer-events: none;
}
.products-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 30px;
    position: relative;
    z-index: 1;
}
.product-card {
    background: var(--white);
    border-radius: 16px;
    overflow: hidden;
    box-shadow: var(--shadow);
    transition: var(--transition);
}
.product-card:hover { transform: translateY(-5px); box-shadow: 0 8px 30px rgba(0,0,0,0.12); }
.product-img {
    height: 220px;
    background: #f0f4f8;
    display: flex; align-items: center; justify-content: center;
    overflow: hidden;
}
.product-img img {
    width: 100%; height: 100%;
    object-fit: contain;
    padding: 10px;
    transition: transform 0.3s ease;
}
.product-card:hover .product-img img { transform: scale(1.05); }
.product-info { padding: 24px; }
.product-info h3 { font-size: 1.15rem; margin-bottom: 8px; color: var(--primary); }
.product-info p { color: var(--text-light); font-size: 0.92rem; line-height: 1.6; }
.product-specs { display: block; margin-top: 12px; padding: 10px 14px; background: #eaf2f8; border-radius: 8px; font-size: 0.82rem !important; color: var(--primary) !important; font-weight: 500; line-height: 1.8; }
.product-specs::before { content: "规格参数"; font-weight: 700; margin-right: 8px; color: var(--accent); }

/* ========== Advantages ========== */
#advantages {
    background: linear-gradient(180deg, #1a1a2e 0%, #16213e 100%);
    color: #fff;
}
#advantages .section-title { color: #fff; }
#advantages .section-tag { background: rgba(255,255,255,0.15); color: #fff; }
#advantages::before {
    content: '';
    position: absolute;
    top: 0; left: 0;
    width: 100%;
    height: 100%;
    background: url('assets/images/facility-bg.png') center/cover;
    opacity: 0.15;
    pointer-events: none;
}
.advantages-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
    gap: 30px;
    position: relative;
    z-index: 1;
}
.advantage-card {
    text-align: center;
    padding: 40px 24px;
    border-radius: 16px;
    background: var(--white);
    box-shadow: var(--shadow);
    transition: var(--transition);
}
.advantage-card:hover { transform: translateY(-5px); }
.adv-icon {
    width: 80px; height: 80px;
    margin: 0 auto 20px;
    background: linear-gradient(135deg, var(--primary), var(--primary-light));
    border-radius: 50%;
    display: flex; align-items: center; justify-content: center;
    font-size: 2rem;
    color: var(--white);
}
.advantage-card h3 { font-size: 1.15rem; margin-bottom: 12px; color: var(--primary); }
.advantage-card p { color: var(--text-light); font-size: 0.92rem; }

/* ========== Patents Gallery ========== */
.patents-gallery {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
    gap: 20px;
    margin-bottom: 20px;
}
.patent-img-card {
    background: var(--white);
    border-radius: 12px;
    overflow: hidden;
    box-shadow: var(--shadow);
    transition: var(--transition);
    border: 1px solid #eee;
}
.patent-img-card:hover { transform: translateY(-4px); box-shadow: 0 8px 30px rgba(0,0,0,0.12); }
.patent-img-card img {
    width: 100%;
    height: 200px;
    object-fit: contain;
    background: #fafafa;
    padding: 10px;
    display: block;
}
.patent-img-card p {
    font-size: 0.85rem;
    color: var(--text);
    text-align: center;
    padding: 12px 10px;
    background: var(--white);
    line-height: 1.4;
    min-height: 50px;
    display: flex;
    align-items: center;
    justify-content: center;
}

/* ========== About ========== */
.about-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
}
.about-text p { font-size: 1.05rem; line-height: 1.8; margin-bottom: 20px; color: var(--text-light); }
.about-stats { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; margin-top: 32px; }
.stat-item {
    text-align: center;
    padding: 24px;
    background: var(--bg-light);
    border-radius: 12px;
}
.stat-number { font-size: 2.5rem; font-weight: 700; color: var(--primary); }
.stat-label { font-size: 0.9rem; color: var(--text-light); margin-top: 4px; }
.about-image {
    display: flex; flex-direction: column; gap: 15px;
}

@media (max-width: 968px) {
    .about-content { grid-template-columns: 1fr; }
}

/* ========== Contact ========== */
.contact-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
}
.contact-info h3 { font-size: 1.5rem; margin-bottom: 24px; color: var(--primary); }
.contact-item {
    display: flex; align-items: flex-start; gap: 16px;
    margin-bottom: 20px;
    padding: 16px;
    background: var(--white);
    border-radius: 12px;
}
.contact-icon { font-size: 1.5rem; }
.contact-item h4 { font-size: 1rem; margin-bottom: 4px; }
.contact-item p { font-size: 0.95rem; color: var(--text-light); }
.contact-form { display: flex; flex-direction: column; gap: 16px; }
.form-group input, .form-group textarea {
    width: 100%;
    padding: 14px 18px;
    border: 2px solid #e0e0e0;
    border-radius: 10px;
    font-size: 1rem;
    font-family: inherit;
    transition: var(--transition);
}
.form-group input:focus, .form-group textarea:focus {
    outline: none;
    border-color: var(--primary);
}
.form-group textarea { min-height: 140px; resize: vertical; }
.btn-submit {
    padding: 14px 36px;
    background: var(--primary);
    color: var(--white);
    border: none;
    border-radius: 50px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
}
.btn-submit:hover { background: var(--primary-light); transform: translateY(-2px); }

@media (max-width: 768px) {
    .contact-grid { grid-template-columns: 1fr; }
}

/* ========== Footer ========== */
.footer {
    background: var(--bg-dark);
    color: var(--white);
    padding: 60px 0 20px;
}
.footer-grid {
    display: grid;
    grid-template-columns: 1.5fr 1fr 1fr 1.2fr;
    gap: 30px;
    padding-bottom: 40px;
    border-bottom: 1px solid rgba(255,255,255,0.1);
}
.footer-brand .logo { display: flex; align-items: center; gap: 10px; font-size: 1.3rem; font-weight: 700; margin-bottom: 16px; }
.footer-brand p { font-size: 0.9rem; opacity: 0.7; line-height: 1.8; }
.footer h4 { font-size: 1rem; margin-bottom: 16px; color: var(--accent-light); }
.footer ul li { margin-bottom: 10px; }
.footer ul a { font-size: 0.9rem; opacity: 0.7; transition: var(--transition); }
.footer ul a:hover { opacity: 1; }
.footer-contact p { font-size: 0.9rem; opacity: 0.7; margin-bottom: 8px; }
.social-links { display: flex; flex-direction: column; gap: 10px; }
.social-item {
    display: flex; align-items: center; gap: 10px;
    padding: 8px 14px;
    background: rgba(255,255,255,0.08);
    border-radius: 8px;
    transition: var(--transition);
    font-size: 0.9rem;
    opacity: 0.7;
    color: #fff;
}
.social-item:hover { background: rgba(255,255,255,0.15); opacity: 1; }
.footer-bottom {
    text-align: center;
    padding-top: 20px;
    font-size: 0.85rem;
    opacity: 0.5;
}

@media (max-width: 968px) {
    .footer-grid { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 480px) {
    .footer-grid { grid-template-columns: 1fr; }
}

/* ========== 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: 480px) {
    .hero h1 { font-size: 1.8rem; }
    .section-title { font-size: 1.8rem; }
    .products-grid { grid-template-columns: 1fr; }
    .advantages-grid { grid-template-columns: 1fr; }
}