/* ========== 基础重置 & 变量 ========== */
:root {
    --primary: #2563eb;
    --primary-dark: #1d4ed8;
    --primary-light: #3b82f6;
    --accent: #0ea5e9;
    --dark: #1e293b;
    --gray: #64748b;
    --light: #f8fafc;
    --white: #ffffff;
    --shadow: 0 4px 6px -1px rgba(0,0,0,0.1), 0 2px 4px -2px rgba(0,0,0,0.1);
    --shadow-lg: 0 20px 25px -5px rgba(0,0,0,0.1), 0 8px 10px -6px rgba(0,0,0,0.1);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', sans-serif;
    color: var(--dark);
    line-height: 1.6;
    overflow-x: hidden;
}

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

a {
    text-decoration: none;
    color: inherit;
}

ul {
    list-style: none;
}

/* ========== 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: 0 1px 3px rgba(0,0,0,0.05);
    transition: all 0.3s ease;
}

.header.scrolled {
    box-shadow: var(--shadow);
}

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

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

.logo-icon {
    font-size: 32px;
}

.logo-text h1 {
    font-size: 20px;
    font-weight: 700;
    color: var(--dark);
    line-height: 1.2;
}

.logo-text span {
    font-size: 11px;
    color: var(--gray);
    letter-spacing: 2px;
    text-transform: uppercase;
}

.nav ul {
    display: flex;
    gap: 32px;
}

.nav a {
    font-size: 15px;
    font-weight: 500;
    color: var(--gray);
    transition: color 0.3s;
    position: relative;
}

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

.nav a::after {
    content: '';
    position: absolute;
    bottom: -6px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--primary);
    transition: width 0.3s;
}

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

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

.menu-toggle span {
    width: 28px;
    height: 2px;
    background: var(--dark);
    transition: all 0.3s;
}

/* ========== Hero Banner ========== */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    background: linear-gradient(135deg, #0f172a 0%, #1e3a5f 40%, #0c4a6e 70%, #155e75 100%);
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -20%;
    width: 800px;
    height: 800px;
    background: radial-gradient(circle, rgba(37,99,235,0.15) 0%, transparent 70%);
    border-radius: 50%;
    animation: float 8s ease-in-out infinite;
}

.hero::after {
    content: '';
    position: absolute;
    bottom: -30%;
    left: -10%;
    width: 600px;
    height: 600px;
    background: radial-gradient(circle, rgba(14,165,233,0.1) 0%, transparent 70%);
    border-radius: 50%;
    animation: float 10s ease-in-out infinite reverse;
}

@keyframes float {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-30px); }
}

.hero-overlay {
    position: absolute;
    inset: 0;
    background: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23ffffff' fill-opacity='0.03'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
}

.hero-content {
    position: relative;
    z-index: 2;
    text-align: center;
    color: var(--white);
    padding: 120px 0 80px;
}

.hero-title {
    font-size: clamp(36px, 6vw, 64px);
    font-weight: 800;
    margin-bottom: 24px;
    background: linear-gradient(135deg, #ffffff 0%, #93c5fd 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: clamp(16px, 2vw, 20px);
    color: rgba(255,255,255,0.8);
    margin-bottom: 40px;
    line-height: 1.8;
}

.hero-btns {
    display: flex;
    gap: 16px;
    justify-content: center;
    flex-wrap: wrap;
}

.btn {
    display: inline-block;
    padding: 14px 36px;
    border-radius: 50px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    border: none;
}

.btn-primary {
    background: var(--primary);
    color: white;
    box-shadow: 0 4px 15px rgba(37,99,235,0.4);
}

.btn-primary:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(37,99,235,0.5);
}

.btn-outline {
    background: transparent;
    color: white;
    border: 2px solid rgba(255,255,255,0.4);
}

.btn-outline:hover {
    border-color: white;
    background: rgba(255,255,255,0.1);
    transform: translateY(-2px);
}

.hero-wave {
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    z-index: 1;
}

.hero-wave svg {
    width: 100%;
    height: 120px;
}

/* ========== 通用区块标题 ========== */
.section-header {
    text-align: center;
    margin-bottom: 60px;
}

.section-header h2 {
    font-size: 36px;
    font-weight: 800;
    color: var(--dark);
    margin-bottom: 8px;
}

.section-subtitle {
    font-size: 14px;
    color: var(--primary);
    letter-spacing: 3px;
    text-transform: uppercase;
    margin-bottom: 16px;
}

.section-line {
    width: 60px;
    height: 4px;
    background: linear-gradient(90deg, var(--primary), var(--accent));
    margin: 0 auto;
    border-radius: 2px;
}

/* ========== 关于我们 ========== */
.about {
    padding: 100px 0;
    background: var(--white);
}

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

.about-text h3 {
    font-size: 28px;
    font-weight: 700;
    margin-bottom: 20px;
    color: var(--dark);
}

.about-text p {
    color: var(--gray);
    margin-bottom: 16px;
    font-size: 16px;
    line-height: 1.8;
}

.about-stats {
    display: flex;
    gap: 40px;
    margin-top: 36px;
}

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

.stat-number {
    display: block;
    font-size: 32px;
    font-weight: 800;
    color: var(--primary);
    margin-bottom: 4px;
}

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

.about-image {
    display: flex;
    justify-content: center;
}

.image-placeholder {
    width: 100%;
    max-width: 480px;
    aspect-ratio: 4/3;
    background: linear-gradient(135deg, #e0e7ff 0%, #c7d2fe 50%, #bae6fd 100%);
    border-radius: 20px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    box-shadow: var(--shadow-lg);
}

.placeholder-icon {
    font-size: 64px;
    margin-bottom: 12px;
}

.image-placeholder span {
    color: var(--gray);
    font-size: 14px;
}

/* ========== 服务项目 ========== */
.services {
    padding: 100px 0;
    background: var(--light);
}

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

.service-card {
    background: var(--white);
    padding: 40px 30px;
    border-radius: 16px;
    text-align: center;
    box-shadow: var(--shadow);
    transition: all 0.4s ease;
    position: relative;
    overflow: hidden;
}

.service-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: linear-gradient(90deg, var(--primary), var(--accent));
    transform: scaleX(0);
    transform-origin: left;
    transition: transform 0.4s ease;
}

.service-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-lg);
}

.service-card:hover::before {
    transform: scaleX(1);
}

.service-icon {
    font-size: 48px;
    margin-bottom: 20px;
}

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

.service-card p {
    color: var(--gray);
    font-size: 15px;
    line-height: 1.7;
}

/* ========== 核心优势 ========== */
.advantages {
    padding: 100px 0;
    background: var(--white);
}

.advantages-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 40px;
}

.advantage-item {
    display: flex;
    gap: 24px;
    padding: 30px;
    border-radius: 16px;
    background: var(--light);
    transition: all 0.3s ease;
}

.advantage-item:hover {
    background: var(--white);
    box-shadow: var(--shadow-lg);
}

.advantage-number {
    font-size: 48px;
    font-weight: 800;
    color: rgba(37,99,235,0.15);
    line-height: 1;
    flex-shrink: 0;
}

.advantage-item h3 {
    font-size: 20px;
    font-weight: 700;
    margin-bottom: 8px;
    color: var(--dark);
}

.advantage-item p {
    color: var(--gray);
    font-size: 15px;
    line-height: 1.7;
}

/* ========== 联系我们 ========== */
.contact {
    padding: 100px 0;
    background: var(--light);
}

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

.contact-info {
    display: flex;
    flex-direction: column;
    gap: 30px;
}

.contact-item {
    display: flex;
    gap: 20px;
    align-items: flex-start;
}

.contact-icon {
    font-size: 28px;
    width: 56px;
    height: 56px;
    background: var(--white);
    border-radius: 14px;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: var(--shadow);
    flex-shrink: 0;
}

.contact-detail h4 {
    font-size: 16px;
    font-weight: 600;
    color: var(--dark);
    margin-bottom: 4px;
}

.contact-detail p {
    color: var(--gray);
    font-size: 15px;
}

.contact-form {
    background: var(--white);
    padding: 40px;
    border-radius: 20px;
    box-shadow: var(--shadow-lg);
}

.contact-form h3 {
    font-size: 22px;
    font-weight: 700;
    margin-bottom: 24px;
    color: var(--dark);
}

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
    margin-bottom: 16px;
}

.contact-form input,
.contact-form textarea {
    width: 100%;
    padding: 14px 18px;
    border: 2px solid #e2e8f0;
    border-radius: 10px;
    font-size: 15px;
    font-family: inherit;
    transition: border-color 0.3s;
    outline: none;
    background: var(--light);
}

.contact-form input:focus,
.contact-form textarea:focus {
    border-color: var(--primary);
    background: var(--white);
}

.contact-form textarea {
    resize: vertical;
    margin-bottom: 20px;
}

.contact-form .btn {
    width: 100%;
}

/* ========== 页脚 ========== */
.footer {
    background: #0f172a;
    color: rgba(255,255,255,0.7);
    padding: 60px 0 0;
}

.footer-content {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: 40px;
    padding-bottom: 40px;
    border-bottom: 1px solid rgba(255,255,255,0.1);
}

.footer-brand h3 {
    font-size: 22px;
    color: white;
    margin-bottom: 16px;
}

.footer-brand p {
    font-size: 14px;
    line-height: 1.8;
}

.footer h4 {
    font-size: 16px;
    color: white;
    margin-bottom: 20px;
}

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

.footer-links a {
    transition: color 0.3s;
}

.footer-links a:hover {
    color: var(--accent);
}

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

.footer-bottom {
    text-align: center;
    padding: 24px 0;
    font-size: 13px;
    color: rgba(255,255,255,0.4);
}

/* ========== 响应式 ========== */
@media (max-width: 768px) {
    .nav {
        display: none;
        position: absolute;
        top: 72px;
        left: 0;
        width: 100%;
        background: white;
        padding: 20px;
        box-shadow: var(--shadow);
    }

    .nav.active {
        display: block;
    }

    .nav ul {
        flex-direction: column;
        gap: 16px;
    }

    .menu-toggle {
        display: flex;
    }

    .about-content {
        grid-template-columns: 1fr;
    }

    .services-grid {
        grid-template-columns: 1fr;
    }

    .advantages-grid {
        grid-template-columns: 1fr;
    }

    .contact-content {
        grid-template-columns: 1fr;
    }

    .form-row {
        grid-template-columns: 1fr;
    }

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

    .about-stats {
        flex-wrap: wrap;
        gap: 20px;
    }
}

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

    .hero-btns {
        flex-direction: column;
        align-items: center;
    }
}