/* ========== 基础样式 ========== */
* { margin: 0; padding: 0; box-sizing: border-box; }
:root {
    --primary: #1a56db;
    --primary-dark: #1244b0;
    --secondary: #0ea5e9;
    --dark: #111827;
    --gray-800: #1f2937;
    --gray-700: #374151;
    --gray-600: #4b5563;
    --gray-400: #9ca3af;
    --gray-200: #e5e7eb;
    --gray-100: #f3f4f6;
    --white: #ffffff;
    --radius: 12px;
    --shadow: 0 4px 24px rgba(0,0,0,0.08);
    --shadow-lg: 0 12px 40px rgba(0,0,0,0.12);
}
html { scroll-behavior: smooth; }
body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
    color: var(--gray-700);
    line-height: 1.7;
    background: var(--white);
}
a { text-decoration: none; color: inherit; transition: color .3s; }
img { max-width: 100%; display: block; }
.container { max-width: 1200px; margin: 0 auto; padding: 0 24px; }

/* ========== 按钮 ========== */
.btn {
    display: inline-block;
    padding: 14px 36px;
    border-radius: 50px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all .3s;
    border: 2px solid transparent;
    text-align: center;
}
.btn-primary {
    background: var(--primary);
    color: var(--white);
    border-color: var(--primary);
}
.btn-primary:hover { background: var(--primary-dark); border-color: var(--primary-dark); transform: translateY(-2px); box-shadow: 0 6px 20px rgba(26,86,219,.35); }
.btn-outline {
    background: transparent;
    color: var(--white);
    border-color: rgba(255,255,255,.6);
}
.btn-outline:hover { background: var(--white); color: var(--primary); transform: translateY(-2px); }
.btn-block { display: block; width: 100%; }

/* ========== 导航栏 ========== */
.header {
    position: fixed;
    top: 0; left: 0; right: 0;
    z-index: 1000;
    padding: 16px 0;
    transition: all .35s;
}
.header.scrolled {
    background: rgba(255,255,255,.97);
    backdrop-filter: blur(10px);
    box-shadow: 0 2px 20px rgba(0,0,0,.08);
    padding: 10px 0;
}
.nav-container { display: flex; align-items: center; justify-content: space-between; }
.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--white);
    display: flex;
    align-items: center;
    gap: 8px;
}
.logo i { color: #fbbf24; }
.header.scrolled .logo { color: var(--primary); }
.nav { display: flex; gap: 32px; }
.nav a {
    color: rgba(255,255,255,.85);
    font-weight: 500;
    font-size: .95rem;
    position: relative;
    padding: 4px 0;
}
.nav a::after {
    content: '';
    position: absolute;
    bottom: 0; left: 0;
    width: 0; height: 2px;
    background: var(--primary);
    transition: width .3s;
}
.nav a:hover::after { width: 100%; }
.header.scrolled .nav a { color: var(--gray-700); }
.header.scrolled .nav a:hover { color: var(--primary); }
.nav-toggle { display: none; background: none; border: none; font-size: 1.5rem; color: var(--white); cursor: pointer; }
.header.scrolled .nav-toggle { color: var(--gray-700); }

/* ========== 主横幅 ========== */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    background: linear-gradient(135deg, #0f172a 0%, #1e3a5f 50%, #0c4a6e 100%);
    overflow: hidden;
}
.hero::before {
    content: '';
    position: absolute;
    inset: 0;
    background:
        radial-gradient(circle at 20% 50%, rgba(59,130,246,.3) 0%, transparent 50%),
        radial-gradient(circle at 80% 20%, rgba(14,165,233,.25) 0%, transparent 40%),
        radial-gradient(circle at 60% 80%, rgba(99,102,241,.2) 0%, transparent 40%);
    animation: heroGlow 8s ease-in-out infinite alternate;
}
@keyframes heroGlow {
    0% { opacity: .7; }
    100% { opacity: 1; }
}
.hero-content { position: relative; z-index: 2; max-width: 800px; padding: 0 24px; }
.hero-title {
    font-size: clamp(2.2rem, 5vw, 3.8rem);
    font-weight: 800;
    color: var(--white);
    line-height: 1.2;
    margin-bottom: 24px;
    letter-spacing: 2px;
}
.hero-subtitle {
    font-size: 1.15rem;
    color: rgba(255,255,255,.75);
    margin-bottom: 40px;
    line-height: 1.8;
}
.hero-buttons { display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; }
.hero-scroll {
    position: absolute;
    bottom: 40px;
    left: 50%;
    transform: translateX(-50%);
    color: rgba(255,255,255,.6);
    font-size: 1.5rem;
    animation: bounce 2s infinite;
    z-index: 2;
}
@keyframes bounce {
    0%,100% { transform: translateX(-50%) translateY(0); }
    50% { transform: translateX(-50%) translateY(12px); }
}

/* ========== 数据统计 ========== */
.stats { background: var(--primary); padding: 60px 0; }
.stats-grid { display: grid; grid-template-columns: repeat(4,1fr); gap: 32px; text-align: center; }
.stat-number {
    font-size: 3rem;
    font-weight: 800;
    color: var(--white);
    line-height: 1;
    margin-bottom: 8px;
}
.stat-number::after { content: '+'; }
.stat-label { color: rgba(255,255,255,.8); font-size: 1rem; }

/* ========== 通用区块 ========== */
.section { padding: 100px 0; }
.section-gray { background: var(--gray-100); }
.section-header { text-align: center; margin-bottom: 60px; }
.section-title {
    font-size: 2.2rem;
    font-weight: 700;
    color: var(--dark);
    margin-bottom: 12px;
    position: relative;
}
.section-title::after {
    content: '';
    display: block;
    width: 60px;
    height: 4px;
    background: var(--primary);
    margin: 16px auto 0;
    border-radius: 2px;
}
.section-subtitle { color: var(--gray-600); font-size: 1.05rem; }

/* ========== 关于我们 ========== */
.about-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 60px; align-items: center; }
.about-img-placeholder {
    background: linear-gradient(135deg, #dbeafe, #bfdbfe);
    border-radius: var(--radius);
    height: 400px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 16px;
    color: var(--primary);
}
.about-img-placeholder i { font-size: 5rem; opacity: .6; }
.about-img-placeholder span { font-size: 1rem; opacity: .5; }
.about-content h3 { font-size: 1.6rem; color: var(--dark); margin-bottom: 16px; }
.about-content p { margin-bottom: 16px; color: var(--gray-600); }
.about-features { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; margin-top: 24px; }
.about-feature {
    display: flex;
    align-items: center;
    gap: 10px;
    font-weight: 500;
    color: var(--gray-700);
}
.about-feature i { color: var(--primary); }

/* ========== 服务项目 ========== */
.services-grid { display: grid; grid-template-columns: repeat(3,1fr); gap: 32px; }
.service-card {
    background: var(--white);
    border-radius: var(--radius);
    padding: 40px 32px;
    box-shadow: var(--shadow);
    transition: all .35s;
    border: 1px solid var(--gray-200);
}
.service-card:hover { transform: translateY(-8px); box-shadow: var(--shadow-lg); border-color: var(--primary); }
.service-icon {
    width: 70px; height: 70px;
    border-radius: 16px;
    background: linear-gradient(135deg, #dbeafe, #bfdbfe);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.8rem;
    color: var(--primary);
    margin-bottom: 24px;
}
.service-card h3 { font-size: 1.25rem; color: var(--dark); margin-bottom: 12px; }
.service-card p { color: var(--gray-600); font-size: .95rem; margin-bottom: 20px; }
.service-link { color: var(--primary); font-weight: 600; font-size: .9rem; display: inline-flex; align-items: center; gap: 6px; }
.service-link:hover { gap: 12px; }

/* ========== 成功案例 ========== */
.cases-grid { display: grid; grid-template-columns: repeat(2,1fr); gap: 24px; }
.case-card { border-radius: var(--radius); overflow: hidden; }
.case-image {
    position: relative;
    height: 280px;
    display: flex;
    align-items: flex-end;
    transition: transform .4s;
}
.case-card:hover .case-image { transform: scale(1.02); }
.case-bg-1 { background: linear-gradient(135deg, #1e3a5f, #0ea5e9); }
.case-bg-2 { background: linear-gradient(135deg, #065f46, #10b981); }
.case-bg-3 { background: linear-gradient(135deg, #7c2d12, #f97316); }
.case-bg-4 { background: linear-gradient(135deg, #581c87, #a855f7); }
.case-overlay {
    width: 100%;
    padding: 32px;
    background: linear-gradient(transparent, rgba(0,0,0,.7));
    color: var(--white);
}
.case-tag {
    display: inline-block;
    background: rgba(255,255,255,.2);
    backdrop-filter: blur(4px);
    padding: 4px 14px;
    border-radius: 50px;
    font-size: .8rem;
    margin-bottom: 10px;
}
.case-overlay h3 { font-size: 1.2rem; margin-bottom: 8px; }
.case-overlay p { font-size: .9rem; opacity: .85; }

/* ========== 团队介绍 ========== */
.team-grid { display: grid; grid-template-columns: repeat(4,1fr); gap: 32px; }
.team-card {
    background: var(--white);
    border-radius: var(--radius);
    padding: 40px 24px;
    text-align: center;
    box-shadow: var(--shadow);
    transition: all .35s;
}
.team-card:hover { transform: translateY(-6px); box-shadow: var(--shadow-lg); }
.team-avatar {
    width: 90px; height: 90px;
    border-radius: 50%;
    background: linear-gradient(135deg, #dbeafe, #93c5fd);
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 20px;
    font-size: 2.5rem;
    color: var(--primary);
}
.team-card h3 { font-size: 1.15rem; color: var(--dark); margin-bottom: 4px; }
.team-role { color: var(--primary); font-weight: 600; font-size: .9rem; margin-bottom: 12px; }
.team-desc { color: var(--gray-600); font-size: .88rem; }

/* ========== 合作伙伴 ========== */
.partners-section { padding: 80px 0; }
.partners-grid {
    display: grid;
    grid-template-columns: repeat(6,1fr);
    gap: 24px;
    text-align: center;
}
.partner-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 10px;
    padding: 30px 16px;
    border-radius: var(--radius);
    border: 1px solid var(--gray-200);
    transition: all .3s;
    color: var(--gray-600);
}
.partner-item:hover { border-color: var(--primary); color: var(--primary); box-shadow: var(--shadow); }
.partner-item i { font-size: 2.2rem; }
.partner-item span { font-size: .9rem; font-weight: 500; }

/* ========== 联系我们 ========== */
.contact-grid { display: grid; grid-template-columns: 1fr 1.2fr; gap: 60px; }
.contact-item {
    display: flex;
    gap: 20px;
    margin-bottom: 32px;
}
.contact-icon {
    width: 56px; height: 56px;
    border-radius: 14px;
    background: linear-gradient(135deg, #dbeafe, #bfdbfe);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
    color: var(--primary);
    flex-shrink: 0;
}
.contact-item h4 { font-size: 1rem; color: var(--dark); margin-bottom: 4px; }
.contact-item p { color: var(--gray-600); }
.contact-form {
    background: var(--white);
    border-radius: var(--radius);
    padding: 40px;
    box-shadow: var(--shadow);
}
.form-row { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.form-group { margin-bottom: 16px; }
.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 14px 18px;
    border: 1.5px solid var(--gray-200);
    border-radius: 10px;
    font-size: .95rem;
    font-family: inherit;
    transition: border-color .3s;
    background: var(--white);
    color: var(--gray-700);
}
.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(26,86,219,.1);
}
.form-group textarea { resize: vertical; }

/* ========== 页脚 ========== */
.footer {
    background: var(--gray-800);
    color: rgba(255,255,255,.7);
    padding: 60px 0 0;
}
.footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 40px; }
.footer-about h3 { color: var(--white); font-size: 1.3rem; margin-bottom: 16px; display: flex; align-items: center; gap: 8px; }
.footer-about h3 i { color: #fbbf24; }
.footer-about p { font-size: .9rem; line-height: 1.8; margin-bottom: 20px; }
.footer-social { display: flex; gap: 12px; }
.footer-social a {
    width: 40px; height: 40px;
    border-radius: 50%;
    background: rgba(255,255,255,.1);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.1rem;
    color: rgba(255,255,255,.7);
    transition: all .3s;
}
.footer-social a:hover { background: var(--primary); color: var(--white); }
.footer-links h4 { color: var(--white); margin-bottom: 20px; font-size: 1.05rem; }
.footer-links a { display: block; margin-bottom: 12px; font-size: .9rem; transition: color .3s; }
.footer-links a:hover { color: var(--secondary); }
.footer-bottom {
    border-top: 1px solid rgba(255,255,255,.1);
    padding: 24px 0;
    margin-top: 40px;
    text-align: center;
    font-size: .85rem;
}

/* ========== 回到顶部 ========== */
.back-to-top {
    position: fixed;
    bottom: 32px; right: 32px;
    width: 48px; height: 48px;
    border-radius: 50%;
    background: var(--primary);
    color: var(--white);
    border: none;
    font-size: 1.1rem;
    cursor: pointer;
    box-shadow: 0 4px 16px rgba(26,86,219,.3);
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px);
    transition: all .35s;
    z-index: 999;
}
.back-to-top.visible { opacity: 1; visibility: visible; transform: translateY(0); }
.back-to-top:hover { background: var(--primary-dark); transform: translateY(-3px); }

/* ========== 动画 ========== */
.fade-in {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity .6s ease, transform .6s ease;
}
.fade-in.visible { opacity: 1; transform: translateY(0); }

/* ========== 响应式 ========== */
@media (max-width: 992px) {
    .about-grid { grid-template-columns: 1fr; }
    .about-image { display: none; }
    .services-grid { grid-template-columns: repeat(2,1fr); }
    .team-grid { grid-template-columns: repeat(2,1fr); }
    .footer-grid { grid-template-columns: 1fr 1fr; gap: 32px; }
    .stats-grid { grid-template-columns: repeat(2,1fr); }
    .partners-grid { grid-template-columns: repeat(3,1fr); }
    .contact-grid { grid-template-columns: 1fr; }
}
@media (max-width: 768px) {
    .nav { display: none; position: absolute; top: 100%; left: 0; right: 0; background: var(--white); flex-direction: column; padding: 24px; gap: 16px; box-shadow: var(--shadow-lg); }
    .nav.active { display: flex; }
    .nav a { color: var(--gray-700) !important; }
    .nav-toggle { display: block; }
    .hero-title { font-size: 2rem; }
    .services-grid { grid-template-columns: 1fr; }
    .cases-grid { grid-template-columns: 1fr; }
    .team-grid { grid-template-columns: 1fr; }
    .partners-grid { grid-template-columns: repeat(2,1fr); }
    .footer-grid { grid-template-columns: 1fr; }
    .form-row { grid-template-columns: 1fr; }
    .section { padding: 60px 0; }
}