/* ===== 基础设置 ===== */
:root {
    --primary: #1a56db;
    --primary-dark: #1e40af;
    --primary-light: #e8f0fe;
    --accent: #3b82f6;
    --text: #1e293b;
    --text-secondary: #64748b;
    --bg: #ffffff;
    --bg-gray: #f8fafc;
    --bg-dark: #0f172a;
    --border: #e2e8f0;
    --radius: 8px;
    --shadow: 0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);
    --shadow-md: 0 4px 6px rgba(0,0,0,0.05), 0 2px 4px rgba(0,0,0,0.04);
    --shadow-lg: 0 20px 40px rgba(0,0,0,0.06);
    --max-width: 1120px;
    --nav-height: 64px;
}

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

html {
    scroll-behavior: smooth;
    scroll-padding-top: var(--nav-height);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
    color: var(--text);
    background: var(--bg);
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
}

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

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

ul { list-style: none; }

img { max-width: 100%; display: block; }

/* ===== 导航栏 ===== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: var(--nav-height);
    background: rgba(255,255,255,0.92);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid transparent;
    z-index: 100;
    transition: border-color 0.3s, box-shadow 0.3s;
}

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

.navbar .container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 100%;
}

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

.logo-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 36px;
    height: 36px;
    background: var(--primary);
    color: white;
    border-radius: 6px;
    font-size: 14px;
    letter-spacing: 1px;
}

.logo-text {
    font-size: 16px;
    color: var(--text);
}

.nav-links {
    display: flex;
    gap: 32px;
}

.nav-links a {
    font-size: 15px;
    color: var(--text-secondary);
    transition: color 0.2s;
    position: relative;
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--primary);
    border-radius: 2px;
    transition: width 0.2s;
}

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

.nav-links a:hover::after {
    width: 100%;
}

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

.mobile-toggle span {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--text);
    border-radius: 2px;
    transition: transform 0.3s, opacity 0.3s;
}

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

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

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

/* ===== 主视觉 ===== */
.hero {
    position: relative;
    padding: 160px 0 120px;
    text-align: center;
    overflow: hidden;
}

.hero .container {
    position: relative;
    z-index: 1;
}

.hero h1 {
    font-size: 48px;
    font-weight: 800;
    line-height: 1.25;
    letter-spacing: -0.5px;
    color: var(--text);
    margin-bottom: 20px;
}

.hero h1 .accent {
    background: linear-gradient(135deg, var(--primary) 0%, var(--accent) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: 18px;
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto 36px;
    line-height: 1.8;
}

.btn-primary {
    display: inline-block;
    padding: 14px 36px;
    background: var(--primary);
    color: white;
    border: none;
    border-radius: var(--radius);
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.2s, transform 0.2s, box-shadow 0.2s;
}

.btn-primary:hover {
    background: var(--primary-dark);
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(26, 86, 219, 0.35);
}

.hero-bg {
    position: absolute;
    top: -60%;
    left: -20%;
    width: 140%;
    height: 200%;
    background: radial-gradient(ellipse at 50% 30%, rgba(59,130,246,0.06) 0%, transparent 60%),
                radial-gradient(ellipse at 80% 20%, rgba(37,99,235,0.04) 0%, transparent 50%);
    pointer-events: none;
}

/* ===== 区块通用 ===== */
section {
    padding: 100px 0;
}

.section-header {
    text-align: center;
    margin-bottom: 60px;
}

.section-header h2 {
    font-size: 32px;
    font-weight: 700;
    color: var(--text);
    margin-bottom: 12px;
}

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

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

.about-text {
    max-width: 760px;
    margin: 0 auto 60px;
    text-align: center;
}

.about-text p {
    font-size: 16px;
    color: var(--text-secondary);
    line-height: 1.9;
}

.about-text p + p {
    margin-top: 16px;
}

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

.value-card {
    background: var(--bg);
    padding: 36px 28px;
    border-radius: var(--radius);
    text-align: center;
    box-shadow: var(--shadow);
    transition: transform 0.2s, box-shadow 0.2s;
}

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

.value-icon {
    width: 56px;
    height: 56px;
    margin: 0 auto 20px;
    padding: 14px;
    border-radius: 12px;
    background: var(--primary-light);
    color: var(--primary);
}

.value-card h3 {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 8px;
    color: var(--text);
}

.value-card p {
    font-size: 14px;
    color: var(--text-secondary);
    line-height: 1.6;
}

/* ===== 服务项目 ===== */
.services-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
}

.service-card {
    background: var(--bg);
    padding: 36px 28px;
    border-radius: var(--radius);
    border: 1px solid var(--border);
    transition: transform 0.2s, box-shadow 0.2s, border-color 0.2s;
}

.service-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: transparent;
}

.service-icon {
    width: 48px;
    height: 48px;
    margin-bottom: 20px;
    padding: 10px;
    border-radius: 10px;
    background: var(--primary-light);
    color: var(--primary);
}

.service-card h3 {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 10px;
    color: var(--text);
}

.service-card p {
    font-size: 14px;
    color: var(--text-secondary);
    line-height: 1.7;
}

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

.contact-grid {
    display: grid;
    grid-template-columns: 1fr 1.2fr;
    gap: 48px;
    align-items: start;
}

.contact-info h3 {
    font-size: 20px;
    font-weight: 600;
    margin-bottom: 24px;
    color: var(--text);
}

.info-item {
    display: flex;
    align-items: center;
    gap: 14px;
    padding: 12px 0;
    color: var(--text-secondary);
    font-size: 15px;
}

.info-item svg {
    width: 20px;
    height: 20px;
    flex-shrink: 0;
    color: var(--primary);
}

.contact-form {
    background: var(--bg);
    padding: 32px;
    border-radius: var(--radius);
    box-shadow: var(--shadow-md);
}

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

.form-group label {
    display: block;
    font-size: 14px;
    font-weight: 500;
    color: var(--text);
    margin-bottom: 6px;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 10px 14px;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    font-size: 15px;
    font-family: inherit;
    color: var(--text);
    background: var(--bg);
    transition: border-color 0.2s, box-shadow 0.2s;
    outline: none;
}

.form-group input:focus,
.form-group textarea:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(26,86,219,0.1);
}

.form-group input::placeholder,
.form-group textarea::placeholder {
    color: #cbd5e1;
}

textarea {
    resize: vertical;
    min-height: 100px;
}

/* ===== 页脚 ===== */
.footer {
    background: var(--bg-dark);
    color: #94a3b8;
    padding: 48px 0 24px;
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-bottom: 32px;
    border-bottom: 1px solid rgba(255,255,255,0.08);
    margin-bottom: 24px;
}

.footer-brand {
    display: flex;
    align-items: center;
    gap: 12px;
}

.footer-brand .logo-icon {
    background: rgba(255,255,255,0.1);
    color: #94a3b8;
}

.footer-brand p {
    font-size: 15px;
    color: #cbd5e1;
}

.footer-links {
    display: flex;
    gap: 28px;
}

.footer-links a {
    font-size: 14px;
    color: #94a3b8;
    transition: color 0.2s;
}

.footer-links a:hover {
    color: white;
}

.footer-bottom {
    text-align: center;
    font-size: 13px;
    color: #64748b;
}

.footer-bottom a {
    color: #64748b;
    transition: color 0.2s;
}

.footer-bottom a:hover {
    color: #94a3b8;
}

/* ===== 动画 ===== */
.fade-in {
    opacity: 0;
    transform: translateY(24px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

/* ===== 响应式 ===== */
@media (max-width: 768px) {
    .nav-links {
        display: none;
        position: absolute;
        top: var(--nav-height);
        left: 0;
        right: 0;
        background: white;
        flex-direction: column;
        padding: 20px 24px;
        gap: 0;
        border-bottom: 1px solid var(--border);
        box-shadow: var(--shadow-md);
    }

    .nav-links.open {
        display: flex;
    }

    .nav-links a {
        padding: 12px 0;
        font-size: 16px;
        border-bottom: 1px solid var(--border);
    }

    .nav-links a:last-child {
        border-bottom: none;
    }

    .nav-links a::after {
        display: none;
    }

    .mobile-toggle {
        display: flex;
    }

    .hero {
        padding: 120px 0 80px;
    }

    .hero h1 {
        font-size: 32px;
    }

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

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

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

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

    .footer-content {
        flex-direction: column;
        gap: 20px;
        text-align: center;
    }

    .footer-links {
        flex-wrap: wrap;
        justify-content: center;
    }
}

@media (max-width: 480px) {
    .hero h1 {
        font-size: 28px;
    }

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

    section {
        padding: 64px 0;
    }
}