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

:root {
    --primary: #0055a4;
    --primary-dark: #003d7a;
    --primary-light: #0077cc;
    --accent: #00a8e8;
    --text: #333333;
    --text-light: #666666;
    --bg: #ffffff;
    --bg-light: #f5f7fa;
    --bg-dark: #0a1628;
    --white: #ffffff;
    --shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 10px 40px rgba(0, 0, 0, 0.12);
    --radius: 8px;
    --transition: 0.3s ease;
}

html {
    scroll-behavior: smooth;
    scroll-padding-top: 80px;
}

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

a { text-decoration: none; color: inherit; }
ul { list-style: none; }
img { max-width: 100%; display: block; }

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

.section {
    padding: 120px 0 100px;
}

.section-title {
    font-size: 36px;
    font-weight: 700;
    text-align: center;
    margin-bottom: 16px;
    color: var(--text);
}

.section-desc {
    text-align: center;
    color: var(--text-light);
    font-size: 18px;
    margin-bottom: 60px;
}

/* ========== Header ========== */
.header {
    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 1px 4px rgba(0, 0, 0, 0.06);
    transition: var(--transition);
}

.header.scrolled {
    box-shadow: 0 2px 12px rgba(0, 0, 0, 0.1);
}

.nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 72px;
}

.logo {
    display: flex;
    flex-direction: column;
    line-height: 1.2;
    text-decoration: none;
}

.logo-img {
    height: 36px;
    width: auto;
    display: block;
    object-fit: contain;
}

.logo-sub {
    font-size: 11px;
    color: var(--text-light);
    letter-spacing: 1px;
    margin-top: 2px;
}

.nav-menu {
    display: flex;
    gap: 40px;
}

.nav-link {
    font-size: 15px;
    font-weight: 500;
    color: var(--text);
    padding: 8px 0;
    position: relative;
    transition: var(--transition);
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--primary);
    transition: var(--transition);
}

.nav-link:hover,
.nav-link.active { color: var(--primary); }

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

.menu-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 4px;
}

.menu-toggle span {
    width: 24px;
    height: 2px;
    background: var(--text);
    transition: var(--transition);
    border-radius: 2px;
}

/* ========== Hero ========== */
.hero {
    position: relative;
    height: 100vh;
    min-height: 600px;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    background: linear-gradient(135deg, #0a1628 0%, #0d2137 30%, #0a3050 60%, #003d6b 100%);
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    inset: 0;
    background: 
        radial-gradient(ellipse at 20% 50%, rgba(0, 168, 232, 0.15) 0%, transparent 50%),
        radial-gradient(ellipse at 80% 50%, rgba(0, 85, 164, 0.15) 0%, transparent 50%);
}

/* sonar wave animation */
.hero::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 600px;
    height: 600px;
    transform: translate(-50%, -50%);
    border: 1px solid rgba(0, 168, 232, 0.1);
    border-radius: 50%;
    animation: sonar-pulse 4s ease-out infinite;
}

@keyframes sonar-pulse {
    0% { width: 0; height: 0; opacity: 0.6; }
    100% { width: 800px; height: 800px; opacity: 0; }
}

.hero-content {
    position: relative;
    z-index: 2;
}

.hero-title {
    font-size: 56px;
    font-weight: 800;
    color: var(--white);
    margin-bottom: 20px;
    letter-spacing: 4px;
    animation: fadeInUp 1s ease;
}

.hero-subtitle {
    font-size: 22px;
    color: rgba(255, 255, 255, 0.8);
    margin-bottom: 12px;
    animation: fadeInUp 1s ease 0.2s both;
}

.hero-desc {
    font-size: 16px;
    color: rgba(255, 255, 255, 0.6);
    margin-bottom: 40px;
    letter-spacing: 2px;
    animation: fadeInUp 1s ease 0.4s both;
}

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

/* ========== Buttons ========== */
.btn {
    display: inline-block;
    padding: 14px 40px;
    font-size: 16px;
    font-weight: 600;
    border-radius: 4px;
    border: none;
    cursor: pointer;
    transition: var(--transition);
    letter-spacing: 1px;
}

.btn-primary {
    background: var(--accent);
    color: var(--white);
}

.btn-primary:hover {
    background: var(--primary-light);
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(0, 168, 232, 0.3);
}

/* ========== About ========== */
.about-hero {
    background: linear-gradient(135deg, #f5f7fa 0%, #e8edf5 100%);
    text-align: center;
    padding: 120px 0 64px;
}

.about-hero h2 {
    font-size: 36px;
    color: var(--text);
    margin-bottom: 16px;
}

.about-hero .hero-desc {
    font-size: 17px;
    color: var(--text-light);
    margin: 0;
}

.company-intro {
    padding: 64px 0;
}

.about-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 80px;
}

.about-text h3 {
    font-size: 24px;
    color: var(--text);
    margin-bottom: 24px;
    padding-bottom: 12px;
    border-bottom: 2px solid var(--primary);
    display: inline-block;
}

.about-text p {
    color: var(--text-light);
    margin-bottom: 16px;
    font-size: 15px;
    line-height: 1.85;
}

.about-culture h3 {
    font-size: 24px;
    color: var(--text);
    margin-bottom: 24px;
    padding-bottom: 12px;
    border-bottom: 2px solid var(--primary);
    display: inline-block;
}

.culture-cards {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.culture-card {
    display: flex;
    align-items: center;
    gap: 20px;
    padding: 24px;
    background: var(--white);
    border: 1px solid #e8e8e8;
    border-radius: var(--radius);
    transition: var(--transition);
}

.culture-card:hover {
    border-color: var(--primary);
    box-shadow: 0 4px 20px rgba(0, 85, 164, 0.06);
    transform: translateX(4px);
}

.culture-icon {
    width: 56px;
    height: 56px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--bg-light);
    border-radius: 12px;
    color: var(--primary);
    flex-shrink: 0;
}

.culture-card h4 {
    font-size: 17px;
    color: var(--text);
    margin-bottom: 4px;
    font-weight: 600;
}

.culture-card p {
    font-size: 14px;
    color: var(--text-light);
    margin: 0;
}

/* ========== Core Values ========== */
.core-values {
    background: var(--bg-light);
    padding: 64px 0;
}

.core-values .section-subtitle {
    text-align: center;
    font-size: 22px;
    color: var(--text);
    margin-bottom: 44px;
    font-weight: 600;
}

.values-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
}

.value-card {
    background: var(--white);
    padding: 36px 32px;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    text-align: center;
    transition: var(--transition);
}

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

.value-icon {
    font-size: 28px;
    color: var(--primary);
    margin-bottom: 12px;
}

.value-card h4 {
    font-size: 18px;
    margin-bottom: 8px;
    color: var(--text);
}

.value-card p {
    color: var(--text-light);
    font-size: 14px;
}

/* ========== Products Overview ========== */
.products { background: var(--bg); }

.product-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 32px;
}

.product-card {
    background: var(--white);
    border-radius: var(--radius);
    overflow: hidden;
    box-shadow: var(--shadow);
    transition: var(--transition);
    display: flex;
    flex-direction: column;
}

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

.product-image {
    height: 200px;
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    cursor: pointer;
}

.product-img {
    width: 100%;
    height: 100%;
    object-fit: contain;
    padding: 20px;
    transition: transform 0.4s ease;
}

.product-image:hover .product-img {
    transform: scale(1.05);
}

.adcp-bg { background: #f0f4f8; }
.dvl-bg { background: #eef5f2; }
.sonar-bg { background: #eef3f6; }

.product-image::before {
    content: '';
    position: absolute;
    inset: 12px;
    border: 1px solid #e0e0e0;
    border-radius: 6px;
    pointer-events: none;
    z-index: 1;
}

.product-title-link {
    display: inline-block;
}

.product-title-link h3 {
    transition: color var(--transition);
}

.product-title-link:hover h3 {
    color: var(--primary);
}

.product-tag {
    position: absolute;
    top: 16px;
    right: 16px;
    background: var(--primary);
    color: var(--white);
    padding: 4px 14px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: 600;
    letter-spacing: 1px;
    z-index: 2;
}

.product-info {
    padding: 28px 28px 32px;
    flex: 1;
    display: flex;
    flex-direction: column;
}

.product-info h3 {
    font-size: 26px;
    font-weight: 700;
    color: var(--text);
    margin-bottom: 2px;
}

.product-fullname {
    font-size: 15px;
    color: var(--primary);
    margin-bottom: 14px;
    font-weight: 500;
}

.product-desc {
    color: var(--text-light);
    font-size: 14px;
    line-height: 1.7;
    margin-bottom: 16px;
    flex: 1;
}

.product-highlights {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-bottom: 16px;
}

.product-highlight {
    padding: 4px 12px;
    background: var(--bg-light);
    border-radius: 4px;
    font-size: 13px;
    color: var(--text);
    border: 1px solid #e8e8e8;
}

.product-highlight .hl-value {
    font-weight: 700;
    color: var(--primary);
}

.product-link {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    font-size: 14px;
    font-weight: 600;
    color: var(--primary);
    transition: var(--transition);
    align-self: flex-start;
}

.product-link:hover { gap: 10px; color: var(--primary-dark); }
.product-link .arrow { transition: transform var(--transition); }
.product-link:hover .arrow { transform: translateX(4px); }

/* ========== Product Detail ========== */
.product-detail { padding: 120px 0 80px; }

.breadcrumb {
    font-size: 13px;
    color: var(--text-light);
    margin-bottom: 40px;
}
.breadcrumb a { color: var(--text); transition: var(--transition); }
.breadcrumb a:hover { color: var(--primary); }
.breadcrumb span { color: var(--primary); font-weight: 500; }

.product-hero {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    gap: 24px;
    flex-wrap: wrap;
    margin-bottom: 32px;
}
.product-hero-name { font-size: 34px; font-weight: 800; color: var(--text); line-height: 1.3; }
.product-hero-name small { font-size: 16px; font-weight: 400; color: var(--text-light); display: block; }
.product-hero-badge {
    padding: 6px 16px;
    border-radius: 20px;
    font-size: 13px;
    font-weight: 600;
    letter-spacing: 1px;
    white-space: nowrap;
    border: 1px solid #e0e0e0;
    background: var(--bg-light);
    color: var(--text);
}
.product-hero-desc {
    font-size: 15px;
    color: var(--text-light);
    line-height: 1.8;
    max-width: 700px;
    margin-bottom: 40px;
    padding-left: 16px;
    border-left: 3px solid var(--bg-light);
}

.detail-section { margin-bottom: 32px; }
.detail-section-title {
    font-size: 13px;
    letter-spacing: 2px;
    color: var(--text-light);
    margin-bottom: 12px;
    text-transform: uppercase;
    padding-bottom: 8px;
    border-bottom: 2px solid #f0f0f0;
}

.tag-row { display: flex; flex-wrap: wrap; gap: 8px; }
.tag {
    padding: 5px 14px;
    border-radius: 4px;
    font-size: 13px;
    font-weight: 500;
    letter-spacing: 0.5px;
    white-space: nowrap;
}
.tag-feature { background: #f0f5fa; color: #1a3a5c; border: 1px solid #d0dde8; }
.tag-app { background: #f5f5f5; color: #555; border: 1px solid #e5e5e5; }

/* Param Table */
.param-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 14px;
    background: var(--white);
    border: 1px solid #e8e8e8;
    border-radius: var(--radius);
    overflow: hidden;
}
.param-table th, .param-table td {
    padding: 12px 18px;
    text-align: left;
    border-bottom: 1px solid #f0f0f0;
}
.param-table th { color: var(--text-light); font-weight: 500; width: 38%; font-size: 13px; background: #fafafa; }
.param-table td { color: var(--text); font-weight: 500; }
.param-table .highlight { color: var(--primary); font-weight: 700; }
.param-table tr:last-child th, .param-table tr:last-child td { border-bottom: none; }
.param-table tr:hover td { background: #fafbfc; }

/* Interface */
.interface-info {
    display: flex;
    gap: 32px;
    flex-wrap: wrap;
    padding: 18px 24px;
    background: #fafafa;
    border-radius: var(--radius);
    border: 1px solid #e8e8e8;
}
.interface-item {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 14px;
    color: var(--text-light);
}
.interface-item .icon {
    width: 32px; height: 32px;
    border-radius: 6px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 13px;
    font-weight: 700;
    flex-shrink: 0;
    background: #f0f5fa;
    color: var(--primary);
}
.interface-item strong { color: var(--text); }

.back-link {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    color: var(--primary);
    font-size: 14px;
    font-weight: 500;
    transition: var(--transition);
    margin-bottom: 20px;
}
.back-link:hover { gap: 10px; color: var(--primary-dark); }

/* ========== Product Gallery ========== */
.product-gallery {
    margin-bottom: 40px;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
    align-items: stretch;
}

.gallery-main {
    border-radius: var(--radius);
    overflow: hidden;
    background: var(--bg-light);
    border: 1px solid #e8e8e8;
    box-shadow: var(--shadow);
    display: flex;
    align-items: center;
    justify-content: center;
}

.gallery-main img {
    width: 100%;
    height: 100%;
    object-fit: contain;
    display: block;
    max-height: 420px;
}

.gallery-thumbs {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.gallery-thumbs img {
    width: 100%;
    height: 100%;
    display: block;
    border-radius: var(--radius);
    border: 1px solid #e8e8e8;
    background: var(--bg-light);
    transition: var(--transition);
    box-shadow: 0 2px 8px rgba(0,0,0,0.04);
    max-height: 420px;
    object-fit: contain;
}

.gallery-thumbs img:hover {
    border-color: var(--primary);
    box-shadow: var(--shadow);
}

/* ========== Contact ========== */
.contact-page { background: var(--white); }

.section-subtitle {
    text-align: center;
    color: var(--text-light);
    font-size: 16px;
    margin: -8px 0 48px;
}

.contact-cards {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
    margin-bottom: 60px;
}

.contact-card {
    background: var(--white);
    border: 1px solid #e8e8e8;
    border-radius: var(--radius);
    padding: 40px 32px;
    text-align: center;
    transition: var(--transition);
}

.contact-card:hover {
    border-color: var(--primary);
    box-shadow: 0 8px 30px rgba(0, 85, 164, 0.08);
    transform: translateY(-2px);
}

.contact-card-icon {
    width: 56px;
    height: 56px;
    margin: 0 auto 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--bg-light);
    border-radius: 50%;
    color: var(--primary);
}

.contact-card h4 {
    font-size: 15px;
    color: var(--text);
    margin-bottom: 10px;
    font-weight: 600;
}

.contact-card p {
    font-size: 14px;
    color: var(--text-light);
    line-height: 1.7;
    margin: 0;
}

.contact-card a {
    display: inline-block;
    font-size: 14px;
    color: var(--primary);
    text-decoration: none;
    transition: var(--transition);
    margin-top: 2px;
}

.contact-card a:hover {
    color: var(--primary-dark);
}

.map-section {
    margin-top: 20px;
}

.map-title {
    font-size: 16px;
    font-weight: 600;
    color: var(--text);
    margin-bottom: 20px;
    padding-bottom: 12px;
    border-bottom: 2px solid #f0f0f0;
}

/* ========== Map ========== */
.map-address {
    text-align: center;
    color: var(--text-light);
    font-size: 14px;
    margin-bottom: 20px;
}

.map-container {
    border-radius: var(--radius);
    overflow: hidden;
    box-shadow: var(--shadow);
}

/* ========== Footer ========== */
.footer {
    background: var(--bg-dark);
    color: rgba(255, 255, 255, 0.6);
    padding: 48px 0 32px;
    font-size: 14px;
}

.footer-inner {
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
    align-items: center;
    gap: 24px;
}

.footer-brand {
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.footer-logo-img {
    height: 32px;
    width: auto;
    display: block;
    object-fit: contain;
}

.footer-name {
    font-size: 12px;
    color: rgba(255, 255, 255, 0.4);
    letter-spacing: 1px;
}

.footer-nav {
    display: flex;
    gap: 24px;
    flex-wrap: wrap;
}

.footer-nav a {
    color: rgba(255, 255, 255, 0.6);
    text-decoration: none;
    transition: var(--transition);
    font-size: 14px;
}

.footer-nav a:hover {
    color: var(--white);
}

.footer-copy {
    width: 100%;
    text-align: center;
    padding-top: 24px;
    margin-top: 24px;
    border-top: 1px solid rgba(255, 255, 255, 0.08);
    font-size: 13px;
    color: rgba(255, 255, 255, 0.35);
}

.beian-link {
    color: rgba(255, 255, 255, 0.35);
    text-decoration: none;
    transition: var(--transition);
}

.beian-link:hover {
    color: var(--white);
}

/* ========== Responsive ========== */
@media (max-width: 992px) {
    .about-grid,
    .product-grid,
    .contact-grid {
        grid-template-columns: 1fr;
        gap: 40px;
    }

    .hero-title { font-size: 40px; }
    .section-title { font-size: 30px; }
    .section { padding: 100px 0 80px; }
}

@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        top: 72px;
        left: 0;
        right: 0;
        background: var(--white);
        flex-direction: column;
        gap: 0;
        box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
        max-height: 0;
        overflow: hidden;
        transition: max-height 0.3s ease;
        padding: 0 0;
    }

    .nav-menu.active {
        max-height: 300px;
        padding: 20px 0;
    }

    .nav-menu li { text-align: center; }

    .nav-link {
        display: block;
        padding: 14px 0;
        font-size: 16px;
    }

    .menu-toggle { display: flex; }

    .hero-title { font-size: 32px; letter-spacing: 2px; }
    .hero-subtitle { font-size: 18px; }

    .product-features { grid-template-columns: 1fr; }

    .gallery-thumbs { grid-template-columns: 1fr; }
    .product-gallery { grid-template-columns: 1fr; }
    .gallery-main img { max-height: 280px; }
    .gallery-thumbs img { max-height: 160px; }
    .product-image { height: 180px; }

    .footer-inner { flex-direction: column; text-align: center; }
    .footer-nav { justify-content: center; }

    .contact-cards { grid-template-columns: 1fr; }
    .contact-card { padding: 32px 24px; }
    .values-grid { grid-template-columns: 1fr; }
}