/* ===== 全局变量 ===== */
:root {
    --primary: #0ea5e9;
    --primary-dark: #0284c7;
    --secondary: #10b981;
    --secondary-dark: #059669;
    --accent: #06b6d4;
    --dark: #0f172a;
    --gray-900: #1e293b;
    --gray-700: #475569;
    --gray-500: #64748b;
    --gray-300: #cbd5e1;
    --gray-100: #f1f5f9;
    --gray-50: #f8fafc;
    --white: #ffffff;
    --gradient: linear-gradient(135deg, #0ea5e9 0%, #10b981 100%);
    --gradient-dark: linear-gradient(135deg, #0c4a6e 0%, #064e3b 100%);
    --shadow-sm: 0 2px 8px rgba(15, 23, 42, 0.06);
    --shadow-md: 0 8px 24px rgba(15, 23, 42, 0.1);
    --shadow-lg: 0 20px 50px rgba(15, 23, 42, 0.15);
    --radius: 16px;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* ===== 重置样式 ===== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

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

body {
    font-family: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
    color: var(--gray-900);
    background: var(--white);
    line-height: 1.7;
    overflow-x: hidden;
}

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: 100px 0;
}

/* ===== 通用组件 ===== */
.section-header {
    text-align: center;
    margin-bottom: 60px;
}

.section-tag {
    display: inline-block;
    font-size: 14px;
    font-weight: 600;
    letter-spacing: 3px;
    color: var(--primary);
    background: rgba(14, 165, 233, 0.1);
    padding: 6px 18px;
    border-radius: 30px;
    margin-bottom: 18px;
}

.section-title {
    font-size: 38px;
    font-weight: 700;
    color: var(--dark);
    margin-bottom: 12px;
}

.section-subtitle {
    font-size: 17px;
    color: var(--gray-500);
}

.gradient-text {
    background: var(--gradient);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 14px 32px;
    font-size: 16px;
    font-weight: 600;
    border-radius: 50px;
    border: none;
    cursor: pointer;
    transition: var(--transition);
    white-space: nowrap;
}

.btn-primary {
    background: var(--gradient);
    color: var(--white);
    box-shadow: 0 8px 20px rgba(14, 165, 233, 0.35);
}

.btn-primary:hover {
    transform: translateY(-3px);
    box-shadow: 0 12px 28px rgba(14, 165, 233, 0.45);
}

.btn-outline {
    background: transparent;
    color: var(--white);
    border: 2px solid rgba(255, 255, 255, 0.6);
}

.btn-outline:hover {
    background: rgba(255, 255, 255, 0.15);
    border-color: var(--white);
}

.btn-full {
    width: 100%;
}

/* ===== 导航栏 ===== */
.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: var(--shadow-sm);
    transition: var(--transition);
}

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

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-weight: 700;
}

.logo-icon {
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--gradient);
    color: var(--white);
    border-radius: 10px;
    font-size: 20px;
    box-shadow: 0 4px 12px rgba(14, 165, 233, 0.4);
}

.logo-text {
    font-size: 22px;
    color: var(--dark);
    letter-spacing: 1px;
}

.nav-menu {
    display: flex;
    gap: 8px;
}

.nav-link {
    display: block;
    padding: 8px 18px;
    font-size: 15px;
    font-weight: 500;
    color: var(--gray-700);
    border-radius: 8px;
    transition: var(--transition);
    position: relative;
}

.nav-link:hover,
.nav-link.active {
    color: var(--primary);
    background: rgba(14, 165, 233, 0.08);
}

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    cursor: pointer;
    padding: 6px;
}

.nav-toggle span {
    width: 26px;
    height: 3px;
    background: var(--dark);
    border-radius: 3px;
    transition: var(--transition);
}

/* ===== Hero 首页 ===== */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding: 100px 0 60px;
    overflow: hidden;
}

.hero-bg {
    position: absolute;
    inset: 0;
    background: var(--gradient-dark);
    z-index: -2;
}

.hero-bg::before {
    content: "";
    position: absolute;
    inset: 0;
    background:
        radial-gradient(circle at 20% 30%, rgba(14, 165, 233, 0.4) 0%, transparent 50%),
        radial-gradient(circle at 80% 70%, rgba(16, 185, 129, 0.35) 0%, transparent 50%);
}

.hero-bg::after {
    content: "";
    position: absolute;
    inset: 0;
    background-image:
        linear-gradient(rgba(255, 255, 255, 0.04) 1px, transparent 1px),
        linear-gradient(90deg, rgba(255, 255, 255, 0.04) 1px, transparent 1px);
    background-size: 50px 50px;
}

.hero-container {
    display: grid;
    grid-template-columns: 1.1fr 0.9fr;
    gap: 60px;
    align-items: center;
}

.hero-tag {
    display: inline-block;
    font-size: 14px;
    font-weight: 600;
    letter-spacing: 2px;
    color: #7dd3fc;
    background: rgba(125, 211, 252, 0.15);
    border: 1px solid rgba(125, 211, 252, 0.3);
    padding: 6px 18px;
    border-radius: 30px;
    margin-bottom: 24px;
}

.hero-title {
    font-size: 56px;
    font-weight: 800;
    color: var(--white);
    line-height: 1.25;
    margin-bottom: 24px;
}

.hero-desc {
    font-size: 17px;
    color: rgba(255, 255, 255, 0.8);
    margin-bottom: 36px;
    max-width: 560px;
}

.hero-btns {
    display: flex;
    gap: 16px;
    margin-bottom: 50px;
}

.hero-stats {
    display: flex;
    gap: 40px;
}

.stat-item {
    display: flex;
    flex-direction: column;
}

.stat-num {
    font-size: 42px;
    font-weight: 800;
    color: var(--white);
    line-height: 1;
}

.stat-label {
    font-size: 14px;
    color: rgba(255, 255, 255, 0.7);
    margin-top: 8px;
}

.hero-image {
    position: relative;
}

.hero-img {
    border-radius: 24px;
    box-shadow: var(--shadow-lg);
    width: 100%;
    height: auto;
}

/* ===== 关于我们 ===== */
.about {
    background: var(--gray-50);
}

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

.about-img {
    border-radius: var(--radius);
    box-shadow: var(--shadow-md);
    width: 100%;
    height: 420px;
    object-fit: cover;
}

.about-content h3 {
    font-size: 28px;
    font-weight: 700;
    color: var(--dark);
    margin-bottom: 18px;
}

.about-content p {
    color: var(--gray-700);
    margin-bottom: 16px;
    font-size: 16px;
}

.about-features {
    margin-top: 30px;
    display: flex;
    flex-direction: column;
    gap: 18px;
}

.about-feature {
    display: flex;
    align-items: center;
    gap: 16px;
    padding: 16px 20px;
    background: var(--white);
    border-radius: 12px;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
}

.about-feature:hover {
    transform: translateX(6px);
    box-shadow: var(--shadow-md);
}

.feature-icon {
    width: 48px;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--gradient);
    color: var(--white);
    border-radius: 12px;
    font-size: 16px;
    font-weight: 700;
    flex-shrink: 0;
}

.feature-info h4 {
    font-size: 17px;
    color: var(--dark);
    margin-bottom: 2px;
}

.feature-info p {
    font-size: 14px;
    color: var(--gray-500);
    margin: 0;
}

/* ===== 核心业务 ===== */
.services {
    background: var(--white);
}

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

.service-card {
    background: var(--white);
    border-radius: var(--radius);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--gray-100);
    transition: var(--transition);
    display: flex;
    flex-direction: column;
}

.service-card:hover {
    transform: translateY(-10px);
    box-shadow: var(--shadow-lg);
    border-color: rgba(14, 165, 233, 0.2);
}

.service-img {
    height: 220px;
    overflow: hidden;
}

.service-img img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: var(--transition);
}

.service-card:hover .service-img img {
    transform: scale(1.08);
}

.service-body {
    padding: 30px;
    position: relative;
    flex: 1;
    display: flex;
    flex-direction: column;
}

.service-num {
    position: absolute;
    top: 24px;
    right: 30px;
    font-size: 48px;
    font-weight: 800;
    color: var(--gray-100);
    line-height: 1;
}

.service-title {
    font-size: 24px;
    font-weight: 700;
    color: var(--dark);
    margin-bottom: 12px;
}

.service-desc {
    color: var(--gray-500);
    font-size: 15px;
    margin-bottom: 20px;
}

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

.service-list li {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 15px;
    color: var(--gray-700);
}

.check {
    width: 20px;
    height: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--gradient);
    color: var(--white);
    border-radius: 50%;
    font-size: 11px;
    flex-shrink: 0;
}

/* ===== 核心优势 ===== */
.advantage {
    background: var(--gray-50);
    position: relative;
}

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

.advantage-card {
    background: var(--white);
    border-radius: var(--radius);
    padding: 36px 30px;
    text-align: center;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
    border-bottom: 4px solid transparent;
}

.advantage-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-md);
    border-bottom-color: var(--primary);
}

.adv-icon {
    font-size: 48px;
    margin-bottom: 18px;
    width: 80px;
    height: 80px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, rgba(14, 165, 233, 0.12), rgba(16, 185, 129, 0.12));
    border-radius: 20px;
    margin: 0 auto 18px;
}

.advantage-card h3 {
    font-size: 20px;
    font-weight: 700;
    color: var(--dark);
    margin-bottom: 12px;
}

.advantage-card p {
    font-size: 15px;
    color: var(--gray-500);
}

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

.contact-grid {
    display: grid;
    grid-template-columns: 1fr 1.1fr;
    gap: 50px;
    align-items: stretch;
}

.contact-info {
    display: flex;
    flex-direction: column;
    gap: 24px;
}

.contact-item {
    display: flex;
    align-items: flex-start;
    gap: 18px;
    padding: 24px;
    background: var(--gray-50);
    border-radius: 14px;
    transition: var(--transition);
}

.contact-item:hover {
    background: var(--white);
    box-shadow: var(--shadow-md);
}

.contact-icon {
    width: 52px;
    height: 52px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--gradient);
    border-radius: 12px;
    font-size: 24px;
    flex-shrink: 0;
}

.contact-detail h4 {
    font-size: 16px;
    color: var(--gray-500);
    margin-bottom: 4px;
    font-weight: 500;
}

.contact-detail p {
    font-size: 17px;
    color: var(--dark);
    font-weight: 600;
}

.contact-link {
    color: var(--primary);
    transition: var(--transition);
}

.contact-link:hover {
    color: var(--primary-dark);
    text-decoration: underline;
}

.contact-form-wrap {
    background: var(--gray-50);
    border-radius: var(--radius);
    padding: 40px;
}

.contact-form h3 {
    font-size: 24px;
    font-weight: 700;
    color: var(--dark);
    margin-bottom: 24px;
}

.form-group {
    margin-bottom: 18px;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 14px 18px;
    font-size: 15px;
    font-family: inherit;
    border: 2px solid var(--gray-300);
    border-radius: 12px;
    background: var(--white);
    transition: var(--transition);
    color: var(--gray-900);
    resize: vertical;
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 4px rgba(14, 165, 233, 0.1);
}

.form-group input::placeholder,
.form-group textarea::placeholder {
    color: var(--gray-500);
}

.form-tip {
    margin-top: 16px;
    text-align: center;
    font-size: 15px;
    min-height: 22px;
    color: var(--secondary);
    font-weight: 500;
}

/* ===== 页脚 ===== */
.footer {
    background: var(--dark);
    color: rgba(255, 255, 255, 0.7);
    padding: 60px 0 0;
}

.footer-top {
    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 .logo {
    margin-bottom: 16px;
}

.footer-brand .logo-text {
    color: var(--white);
}

.footer-brand p {
    font-size: 15px;
    line-height: 1.8;
    max-width: 400px;
}

.footer-links h4 {
    color: var(--white);
    font-size: 17px;
    margin-bottom: 18px;
    font-weight: 600;
}

.footer-links ul {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.footer-links a {
    font-size: 15px;
    transition: var(--transition);
}

.footer-links a:hover {
    color: var(--primary);
    padding-left: 6px;
}

.footer-bottom {
    padding: 24px 0;
    text-align: center;
    font-size: 14px;
}

/* ===== 返回顶部 ===== */
.back-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 48px;
    height: 48px;
    background: var(--gradient);
    color: var(--white);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 22px;
    cursor: pointer;
    box-shadow: 0 6px 20px rgba(14, 165, 233, 0.4);
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px);
    transition: var(--transition);
    z-index: 999;
}

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

.back-top:hover {
    transform: translateY(-4px);
}

/* ===== 滚动动画 ===== */
.reveal {
    opacity: 0;
    transform: translateY(40px);
    transition: opacity 0.7s ease, transform 0.7s ease;
}

.reveal.active {
    opacity: 1;
    transform: translateY(0);
}

/* ===== 响应式 ===== */
@media (max-width: 992px) {
    .hero-container {
        grid-template-columns: 1fr;
        gap: 40px;
    }

    .hero-image {
        order: -1;
        max-width: 500px;
        margin: 0 auto;
    }

    .hero-title {
        font-size: 42px;
    }

    .about-grid,
    .contact-grid {
        grid-template-columns: 1fr;
        gap: 40px;
    }

    .services-grid,
    .advantage-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .footer-top {
        grid-template-columns: 1fr 1fr;
    }

    .footer-brand {
        grid-column: 1 / -1;
    }
}

@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        top: 72px;
        left: 0;
        right: 0;
        background: var(--white);
        flex-direction: column;
        padding: 16px 24px;
        gap: 4px;
        box-shadow: var(--shadow-md);
        transform: translateY(-150%);
        transition: var(--transition);
        max-height: calc(100vh - 72px);
        overflow-y: auto;
    }

    .nav-menu.open {
        transform: translateY(0);
    }

    .nav-link {
        padding: 12px 18px;
    }

    .nav-toggle {
        display: flex;
    }

    .nav-toggle.open span:nth-child(1) {
        transform: rotate(45deg) translate(6px, 6px);
    }

    .nav-toggle.open span:nth-child(2) {
        opacity: 0;
    }

    .nav-toggle.open span:nth-child(3) {
        transform: rotate(-45deg) translate(6px, -6px);
    }

    .section {
        padding: 70px 0;
    }

    .section-title {
        font-size: 30px;
    }

    .hero {
        padding: 110px 0 50px;
    }

    .hero-title {
        font-size: 34px;
    }

    .hero-desc {
        font-size: 16px;
    }

    .hero-btns {
        flex-direction: column;
    }

    .hero-stats {
        gap: 24px;
        flex-wrap: wrap;
    }

    .stat-num {
        font-size: 32px;
    }

    .services-grid,
    .advantage-grid,
    .footer-top {
        grid-template-columns: 1fr;
    }

    .about-img {
        height: 280px;
    }

    .contact-form-wrap {
        padding: 28px;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 16px;
    }

    .section-title {
        font-size: 26px;
    }

    .hero-title {
        font-size: 28px;
    }

    .hero-stats {
        gap: 18px;
    }

    .stat-num {
        font-size: 28px;
    }
}