/* ========== 基础变量与重置 ========== */
:root {
    /* 青绿淡雅配色 */
    --primary: #2a9d8f;        /* 主色：青绿 */
    --primary-light: #8ecae6;  /* 浅色：天蓝 */
    --primary-dark: #264653;   /* 深色：深蓝灰 */
    --primary-bg: #e9f7f5;     /* 主色背景：极浅青绿 */
    --accent: #52b788;         /* 点缀色：薄荷绿 */
    
    /* 中性色 */
    --text-main: #2c3e50;      /* 主文字 */
    --text-sub: #6b7c8e;       /* 次要文字 */
    --text-light: #95a5a6;     /* 浅色文字 */
    --bg-white: #ffffff;
    --bg-gray: #f8fafb;
    --bg-light: #f0f7f9;
    --border: #e0eced;
    --border-light: #eef5f6;
    
    /* 状态色 */
    --success: #27ae60;
    --warning: #f39c12;
    --danger: #e74c3c;
    
    /* 尺寸 */
    --container-max: 1200px;
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 16px;
    
    /* 阴影 */
    --shadow-sm: 0 2px 8px rgba(38, 70, 83, 0.06);
    --shadow-md: 0 4px 20px rgba(38, 70, 83, 0.08);
    --shadow-lg: 0 10px 40px rgba(38, 70, 83, 0.12);
    
    /* 过渡 */
    --transition: 0.3s ease;
    --transition-slow: 0.5s ease;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
    font-size: 15px;
    line-height: 1.7;
    color: var(--text-main);
    background-color: var(--bg-white);
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4, h5, h6 {
    color: var(--text-main);
    font-weight: 600;
    line-height: 1.4;
}

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

a:hover {
    color: var(--primary);
}

ul, ol {
    list-style: none;
}

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

input, textarea, select, button {
    font-family: inherit;
    font-size: inherit;
    outline: none;
    border: none;
    background: none;
}

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

/* ========== 通用按钮 ========== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 12px 32px;
    font-size: 15px;
    font-weight: 500;
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: all var(--transition);
    text-align: center;
    border: 1px solid transparent;
}

.btn-primary {
    background-color: var(--primary);
    color: #fff;
}

.btn-primary:hover {
    background-color: var(--primary-dark);
    color: #fff;
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(42, 157, 143, 0.3);
}

.btn-outline {
    background-color: transparent;
    color: #fff;
    border-color: rgba(255, 255, 255, 0.6);
}

.btn-outline:hover {
    background-color: rgba(255, 255, 255, 0.15);
    color: #fff;
    transform: translateY(-2px);
}

.btn-full {
    width: 100%;
}

/* ========== 通用 Section ========== */
.section {
    padding: 100px 0;
    position: relative;
}

.section.gray {
    background-color: var(--bg-gray);
}

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

.section-tag {
    display: inline-block;
    font-size: 13px;
    color: var(--primary);
    letter-spacing: 3px;
    font-weight: 600;
    margin-bottom: 12px;
}

.section-title {
    font-size: 36px;
    color: var(--text-main);
    margin-bottom: 16px;
    position: relative;
}

.title-line {
    width: 50px;
    height: 3px;
    background: linear-gradient(90deg, var(--primary), var(--accent));
    margin: 0 auto;
    border-radius: 2px;
}

.section-subtitle {
    color: var(--text-sub);
    font-size: 16px;
    margin-top: 20px;
    max-width: 640px;
    margin-left: auto;
    margin-right: auto;
}

/* ========== 导航栏 ========== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background-color: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    transition: all var(--transition);
    border-bottom: 1px solid transparent;
}

.navbar.scrolled {
    box-shadow: var(--shadow-sm);
    border-bottom-color: var(--border-light);
}

.nav-container {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 24px;
    height: 72px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 20px;
    font-weight: 700;
    color: var(--primary-dark);
}

.logo-icon {
    font-size: 28px;
}

.logo-text {
    background: linear-gradient(135deg, var(--primary), var(--accent));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

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

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

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

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

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

.nav-right {
    display: flex;
    align-items: center;
    gap: 24px;
}

.lang-switch {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 14px;
}

.lang-btn {
    padding: 4px 10px;
    border-radius: 4px;
    cursor: pointer;
    color: var(--text-sub);
    transition: all var(--transition);
}

.lang-btn:hover {
    color: var(--primary);
}

.lang-btn.active {
    color: #fff;
    background-color: var(--primary);
}

.lang-divider {
    color: var(--text-light);
}

.menu-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    cursor: pointer;
    padding: 8px;
}

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

.menu-toggle.active span:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
}

.menu-toggle.active span:nth-child(2) {
    opacity: 0;
}

.menu-toggle.active span:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
}

/* ========== Hero 首屏 ========== */
.hero {
    min-height: 100vh;
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    color: #fff;
}

.hero-bg {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, #264653 0%, #2a9d8f 50%, #52b788 100%);
    z-index: 1;
}

.hero-bg::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle at 30% 70%, rgba(142, 202, 230, 0.15) 0%, transparent 50%),
                radial-gradient(circle at 70% 30%, rgba(82, 183, 136, 0.2) 0%, transparent 50%),
                radial-gradient(circle at 50% 50%, rgba(255, 255, 255, 0.05) 0%, transparent 60%);
    animation: floatBg 20s ease-in-out infinite;
}

@keyframes floatBg {
    0%, 100% { transform: translate(0, 0) scale(1); }
    50% { transform: translate(-2%, -2%) scale(1.05); }
}

.hero-content {
    position: relative;
    z-index: 2;
    text-align: center;
    padding: 0 24px;
    max-width: 860px;
}

.hero-title {
    font-size: 54px;
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: 24px;
    text-shadow: 0 2px 20px rgba(0, 0, 0, 0.15);
    animation: fadeInUp 0.8s ease;
}

.hero-subtitle {
    font-size: 20px;
    font-weight: 400;
    opacity: 0.9;
    margin-bottom: 48px;
    animation: fadeInUp 0.8s ease 0.2s backwards;
}

.hero-btns {
    display: flex;
    gap: 20px;
    justify-content: center;
    flex-wrap: wrap;
    animation: fadeInUp 0.8s ease 0.4s backwards;
}

.hero-btns .btn {
    min-width: 160px;
}

.hero-scroll {
    position: absolute;
    bottom: 40px;
    left: 50%;
    transform: translateX(-50%);
    z-index: 2;
    text-align: center;
    font-size: 13px;
    opacity: 0.7;
    animation: bounce 2s ease-in-out infinite;
}

.scroll-arrow {
    font-size: 20px;
    margin-top: 8px;
}

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

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

/* ========== 关于我们 ========== */
.about {
    background-color: var(--bg-white);
}

.about-content {
    display: grid;
    grid-template-columns: 1.2fr 1fr;
    gap: 60px;
    align-items: start;
}

.about-desc {
    color: var(--text-sub);
    font-size: 16px;
    line-height: 1.9;
    margin-bottom: 20px;
}

.about-stats {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 24px;
    margin-top: 40px;
    padding: 32px;
    background-color: var(--primary-bg);
    border-radius: var(--radius-lg);
}

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

.stat-num {
    font-size: 36px;
    font-weight: 700;
    color: var(--primary);
    line-height: 1;
    margin-bottom: 8px;
}

.stat-num span {
    font-size: 20px;
    font-weight: 600;
}

.stat-label {
    font-size: 14px;
    color: var(--text-sub);
}

.about-visual {
    display: flex;
    flex-direction: column;
    gap: 24px;
}

.about-card {
    padding: 32px;
    background-color: var(--bg-white);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    transition: all var(--transition);
    position: relative;
    overflow: hidden;
}

.about-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 4px;
    height: 100%;
    background: linear-gradient(180deg, var(--primary), var(--accent));
}

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

.about-card.card-2 {
    margin-left: 40px;
}

.card-icon {
    font-size: 40px;
    margin-bottom: 16px;
}

.about-card h3 {
    font-size: 20px;
    margin-bottom: 12px;
    color: var(--primary-dark);
}

.about-card p {
    color: var(--text-sub);
    line-height: 1.8;
}

/* ========== 产品服务 ========== */
.services {
    background-color: var(--bg-gray);
}

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

.service-card {
    padding: 40px;
    background-color: var(--bg-white);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-light);
    transition: all var(--transition);
    position: relative;
    overflow: hidden;
}

.service-card::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 0;
    background: linear-gradient(135deg, var(--primary), var(--accent));
    transition: height var(--transition-slow);
    opacity: 0.03;
    z-index: 0;
}

.service-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary-light);
}

.service-card:hover::after {
    height: 100%;
}

.service-card > * {
    position: relative;
    z-index: 1;
}

.service-icon {
    font-size: 52px;
    margin-bottom: 24px;
    display: inline-block;
    transition: transform var(--transition);
}

.service-card:hover .service-icon {
    transform: scale(1.1) rotate(-5deg);
}

.service-title {
    font-size: 22px;
    margin-bottom: 16px;
    color: var(--primary-dark);
}

.service-desc {
    color: var(--text-sub);
    line-height: 1.9;
    margin-bottom: 24px;
}

.service-list {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.service-list li {
    color: var(--text-main);
    font-size: 14px;
    padding-left: 20px;
    position: relative;
}

.service-list li::before {
    content: '✓';
    position: absolute;
    left: 0;
    top: 0;
    color: var(--primary);
    font-weight: 700;
    font-size: 13px;
}

/* ========== 核心优势 ========== */
.advantages {
    background-color: var(--bg-white);
}

.adv-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 32px;
}

.adv-item {
    padding: 40px 32px;
    text-align: center;
    background-color: var(--bg-gray);
    border-radius: var(--radius-lg);
    transition: all var(--transition);
    border: 1px solid transparent;
}

.adv-item:hover {
    background-color: var(--bg-white);
    border-color: var(--border);
    box-shadow: var(--shadow-md);
    transform: translateY(-4px);
}

.adv-icon {
    width: 72px;
    height: 72px;
    margin: 0 auto 24px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, var(--primary-bg), var(--bg-light));
    border-radius: 50%;
    font-size: 36px;
    transition: all var(--transition);
}

.adv-item:hover .adv-icon {
    background: linear-gradient(135deg, var(--primary), var(--accent));
    transform: scale(1.1);
}

.adv-item h3 {
    font-size: 20px;
    margin-bottom: 12px;
    color: var(--primary-dark);
}

.adv-item p {
    color: var(--text-sub);
    font-size: 14px;
    line-height: 1.8;
}

/* ========== 联系我们 ========== */
.contact {
    background-color: var(--bg-gray);
}

.contact-content {
    display: grid;
    grid-template-columns: 1fr 1.2fr;
    gap: 60px;
}

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

.info-item {
    display: flex;
    gap: 20px;
    padding: 24px;
    background-color: var(--bg-white);
    border-radius: var(--radius-md);
    border: 1px solid var(--border-light);
    transition: all var(--transition);
}

.info-item:hover {
    box-shadow: var(--shadow-sm);
    transform: translateX(6px);
    border-color: var(--primary-light);
}

.info-icon {
    flex-shrink: 0;
    width: 52px;
    height: 52px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, var(--primary-bg), var(--bg-light));
    border-radius: var(--radius-sm);
    font-size: 24px;
}

.info-item h4 {
    font-size: 16px;
    color: var(--primary-dark);
    margin-bottom: 6px;
}

.info-item p {
    color: var(--text-sub);
    font-size: 14px;
    margin-bottom: 2px;
}

.contact-form {
    padding: 40px;
    background-color: var(--bg-white);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
}

.contact-form h3 {
    font-size: 24px;
    margin-bottom: 28px;
    color: var(--primary-dark);
}

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
}

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

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-size: 14px;
    font-weight: 500;
    color: var(--text-main);
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 12px 16px;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    background-color: var(--bg-gray);
    color: var(--text-main);
    transition: all var(--transition);
    resize: vertical;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    border-color: var(--primary);
    background-color: var(--bg-white);
    box-shadow: 0 0 0 3px rgba(42, 157, 143, 0.1);
}

/* ========== 页脚 ========== */
.footer {
    background-color: var(--primary-dark);
    color: #b8c5cc;
    padding-top: 72px;
    padding-bottom: 24px;
}

.footer-main {
    display: grid;
    grid-template-columns: 1.5fr 1fr 1fr 1fr;
    gap: 48px;
    padding-bottom: 48px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.footer .logo {
    margin-bottom: 20px;
    color: #fff;
}

.footer .logo-text {
    background: linear-gradient(135deg, #fff, var(--primary-light));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.brand-desc {
    font-size: 14px;
    line-height: 1.9;
    opacity: 0.8;
}

.footer-links h4,
.footer-contact h4 {
    color: #fff;
    font-size: 16px;
    margin-bottom: 20px;
    position: relative;
    padding-bottom: 12px;
}

.footer-links h4::after,
.footer-contact h4::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 30px;
    height: 2px;
    background-color: var(--primary);
}

.footer-links ul li {
    margin-bottom: 10px;
    font-size: 14px;
}

.footer-links ul li a {
    opacity: 0.75;
    transition: all var(--transition);
}

.footer-links ul li a:hover {
    opacity: 1;
    color: var(--primary-light);
    padding-left: 4px;
}

.footer-contact p {
    margin-bottom: 10px;
    font-size: 14px;
    opacity: 0.85;
}

.footer-contact .addr {
    line-height: 1.7;
}

.footer-bottom {
    padding-top: 28px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 16px;
    font-size: 13px;
}

.copyright {
    opacity: 0.7;
}

.rights {
    opacity: 0.7;
}

.icp a {
    opacity: 0.7;
    color: #b8c5cc;
    transition: all var(--transition);
}

.icp a:hover {
    opacity: 1;
    color: #fff;
}

/* ========== 返回顶部 ========== */
.back-top {
    position: fixed;
    bottom: 40px;
    right: 32px;
    width: 48px;
    height: 48px;
    background-color: var(--primary);
    color: #fff;
    border-radius: 50%;
    font-size: 20px;
    cursor: pointer;
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px);
    transition: all var(--transition);
    box-shadow: 0 4px 20px rgba(42, 157, 143, 0.3);
    z-index: 999;
}

.back-top.visible {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.back-top:hover {
    background-color: var(--primary-dark);
    transform: translateY(-4px);
}

/* ========== 响应式适配 ========== */
@media (max-width: 992px) {
    .section {
        padding: 80px 0;
    }
    .section-title {
        font-size: 30px;
    }
    .hero-title {
        font-size: 42px;
    }
    .hero-subtitle {
        font-size: 18px;
    }
    .about-content,
    .contact-content {
        grid-template-columns: 1fr;
        gap: 40px;
    }
    .about-card.card-2 {
        margin-left: 0;
    }
    .footer-main {
        grid-template-columns: 1fr 1fr;
        gap: 36px;
    }
    .adv-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    .services-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        top: 72px;
        left: 0;
        right: 0;
        background-color: #fff;
        box-shadow: var(--shadow-md);
        padding: 20px 24px;
        transform: translateY(-150%);
        transition: transform var(--transition);
    }
    .nav-menu.active {
        transform: translateY(0);
    }
    .nav-menu ul {
        flex-direction: column;
        gap: 16px;
    }
    .menu-toggle {
        display: flex;
    }
    .section {
        padding: 64px 0;
    }
    .section-header {
        margin-bottom: 48px;
    }
    .section-title {
        font-size: 26px;
    }
    .hero {
        min-height: 90vh;
    }
    .hero-title {
        font-size: 32px;
    }
    .hero-subtitle {
        font-size: 16px;
        margin-bottom: 36px;
    }
    .hero-btns {
        flex-direction: column;
        gap: 12px;
    }
    .hero-btns .btn {
        width: 100%;
        max-width: 280px;
    }
    .about-stats {
        grid-template-columns: repeat(2, 1fr);
        gap: 20px;
        padding: 24px;
    }
    .stat-num {
        font-size: 28px;
    }
    .adv-grid {
        grid-template-columns: 1fr;
        gap: 20px;
    }
    .form-row {
        grid-template-columns: 1fr;
        gap: 0;
    }
    .contact-form {
        padding: 28px 20px;
    }
    .footer-main {
        grid-template-columns: 1fr;
        gap: 32px;
    }
    .footer-bottom {
        flex-direction: column;
        text-align: center;
    }
    .back-top {
        right: 20px;
        bottom: 24px;
        width: 42px;
        height: 42px;
    }
}

@media (max-width: 480px) {
    .nav-container,
    .container {
        padding: 0 16px;
    }
    .hero-title {
        font-size: 26px;
    }
    .section-title {
        font-size: 22px;
    }
    .service-card,
    .about-card {
        padding: 24px;
    }
    .service-icon {
        font-size: 42px;
    }
    .service-title {
        font-size: 18px;
    }
    .lang-switch {
        font-size: 12px;
    }
    .logo-text {
        font-size: 17px;
    }
}