:root {
    --feishu-blue: #2E6CF5;
    --feishu-cyan: #00C8AE;
    --feishu-dark: #1D2129;
    --feishu-gray: #86909C;
    --feishu-light: #F2F3F5;
    --white: #FFFFFF;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Noto Sans SC', 'PingFang SC', 'Microsoft YaHei', sans-serif;
    line-height: 1.6;
    color: var(--feishu-dark);
    background-color: var(--white);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* 导航栏 */
nav {
    background: var(--white);
    box-shadow: 0 2px 8px rgba(0,0,0,0.08);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 16px 20px;
    max-width: 1200px;
    margin: 0 auto;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 24px;
    font-weight: 700;
    color: var(--feishu-blue);
    text-decoration: none;
}

.logo-icon {
    width: 32px;
    height: 32px;
    background: linear-gradient(135deg, var(--feishu-blue), var(--feishu-cyan));
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--white);
    font-weight: bold;
}

.nav-links {
    display: flex;
    gap: 32px;
    list-style: none;
}

.nav-links a {
    text-decoration: none;
    color: var(--feishu-dark);
    font-weight: 500;
    transition: color 0.3s;
}

.nav-links a:hover,
.nav-links a.active {
    color: var(--feishu-blue);
}

.nav-cta {
    display: flex;
    gap: 12px;
}

.btn {
    padding: 10px 24px;
    border-radius: 8px;
    font-weight: 600;
    text-decoration: none;
    transition: all 0.3s;
    cursor: pointer;
    border: none;
    font-size: 14px;
}

.btn-primary {
    background: var(--feishu-blue);
    color: var(--white);
}

.btn-primary:hover {
    background: #2356C4;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(46, 108, 245, 0.3);
}

.btn-secondary {
    background: var(--white);
    color: var(--feishu-dark);
    border: 1px solid var(--feishu-light);
}

.btn-secondary:hover {
    background: var(--feishu-light);
}

/* Hero区域 */
.hero {
    padding: 100px 0;
    background: linear-gradient(135deg, #F8F9FF 0%, #F0FFF9 100%);
}

.hero-content {
    text-align: center;
    max-width: 800px;
    margin: 0 auto;
}

.hero h1 {
    font-size: 48px;
    font-weight: 700;
    margin-bottom: 24px;
    color: var(--feishu-dark);
    line-height: 1.2;
}

.hero p {
    font-size: 18px;
    color: var(--feishu-gray);
    margin-bottom: 40px;
    line-height: 1.8;
}

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

/* 功能特点 */
.features {
    padding: 80px 0;
    background: var(--white);
}

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

.section-title h2 {
    font-size: 36px;
    font-weight: 700;
    margin-bottom: 16px;
}

.section-title p {
    color: var(--feishu-gray);
    font-size: 16px;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 32px;
}

.feature-card {
    padding: 32px;
    background: var(--white);
    border-radius: 16px;
    border: 1px solid var(--feishu-light);
    transition: all 0.3s;
}

.feature-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 12px 32px rgba(0,0,0,0.08);
    border-color: var(--feishu-blue);
}

.feature-icon {
    width: 56px;
    height: 56px;
    background: linear-gradient(135deg, var(--feishu-blue), var(--feishu-cyan));
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 20px;
    font-size: 24px;
}

.feature-card h3 {
    font-size: 20px;
    margin-bottom: 12px;
}

.feature-card p {
    color: var(--feishu-gray);
    line-height: 1.7;
}

/* 优势展示 */
.advantages {
    padding: 80px 0;
    background: var(--feishu-light);
}

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

.advantages-text h2 {
    font-size: 36px;
    margin-bottom: 24px;
}

.advantages-text p {
    color: var(--feishu-gray);
    margin-bottom: 32px;
    line-height: 1.8;
}

.advantages-list {
    list-style: none;
}

.advantages-list li {
    padding: 16px 0;
    border-bottom: 1px solid rgba(0,0,0,0.08);
    display: flex;
    align-items: center;
    gap: 12px;
}

.advantages-list li:before {
    content: "✓";
    color: var(--feishu-cyan);
    font-weight: bold;
    font-size: 20px;
}

.advantages-image {
    background: linear-gradient(135deg, var(--feishu-blue), var(--feishu-cyan));
    border-radius: 20px;
    height: 400px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--white);
    font-size: 24px;
}

/* 用户评价 */
.testimonials {
    padding: 80px 0;
    background: var(--white);
}

.testimonials-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 32px;
}

.testimonial-card {
    padding: 32px;
    background: var(--feishu-light);
    border-radius: 16px;
}

.testimonial-quote {
    font-size: 16px;
    line-height: 1.8;
    margin-bottom: 24px;
    color: var(--feishu-dark);
}

.testimonial-author {
    display: flex;
    align-items: center;
    gap: 12px;
}

.author-avatar {
    width: 48px;
    height: 48px;
    background: var(--feishu-blue);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--white);
    font-weight: bold;
}

.author-info h4 {
    font-size: 16px;
    margin-bottom: 4px;
}

.author-info p {
    font-size: 14px;
    color: var(--feishu-gray);
}

/* 下载页面样式 */
.download-section {
    padding: 80px 0;
}

.download-platforms {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 24px;
    margin-top: 48px;
}

.platform-card {
    padding: 32px;
    background: var(--white);
    border: 2px solid var(--feishu-light);
    border-radius: 16px;
    text-align: center;
    transition: all 0.3s;
    cursor: pointer;
}

.platform-card:hover {
    border-color: var(--feishu-blue);
    transform: translateY(-4px);
    box-shadow: 0 8px 24px rgba(46, 108, 245, 0.15);
}

.platform-icon {
    width: 64px;
    height: 64px;
    margin: 0 auto 20px;
    background: linear-gradient(135deg, var(--feishu-blue), var(--feishu-cyan));
    border-radius: 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 32px;
    color: var(--white);
}

.platform-card h3 {
    font-size: 20px;
    margin-bottom: 8px;
}

.platform-card p {
    color: var(--feishu-gray);
    font-size: 14px;
}

.system-requirements {
    margin-top: 60px;
    padding: 40px;
    background: var(--feishu-light);
    border-radius: 16px;
}

.system-requirements h3 {
    margin-bottom: 24px;
}

/* 功能详情页 */
.feature-detail {
    padding: 60px 0;
    border-bottom: 1px solid var(--feishu-light);
}

.feature-detail:last-child {
    border-bottom: none;
}

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

.feature-detail h2 {
    font-size: 32px;
    margin-bottom: 20px;
}

.feature-detail p {
    color: var(--feishu-gray);
    line-height: 1.8;
    margin-bottom: 24px;
}

.feature-detail-image {
    background: linear-gradient(135deg, #E8F0FF, #E0FFF8);
    border-radius: 16px;
    height: 300px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--feishu-blue);
    font-size: 48px;
}

/* 关于页 */
.about-hero {
    padding: 100px 0;
    background: linear-gradient(135deg, var(--feishu-blue), var(--feishu-cyan));
    color: var(--white);
    text-align: center;
}

.about-hero h1 {
    font-size: 48px;
    margin-bottom: 16px;
}

.about-hero p {
    font-size: 20px;
    opacity: 0.9;
}

.timeline {
    padding: 80px 0;
}

.timeline-item {
    display: grid;
    grid-template-columns: 200px 1fr;
    gap: 40px;
    padding: 32px 0;
    border-left: 3px solid var(--feishu-blue);
    margin-left: 100px;
    padding-left: 40px;
}

.timeline-year {
    font-size: 24px;
    font-weight: 700;
    color: var(--feishu-blue);
}

.timeline-content h3 {
    font-size: 20px;
    margin-bottom: 12px;
}

.timeline-content p {
    color: var(--feishu-gray);
}

/* 页脚 */
footer {
    background: var(--feishu-dark);
    color: var(--white);
    padding: 60px 0 30px;
}

.footer-content {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: 60px;
    margin-bottom: 40px;
}

.footer-brand .logo {
    color: var(--white);
    margin-bottom: 20px;
}

.footer-brand p {
    color: rgba(255,255,255,0.7);
    line-height: 1.8;
}

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

.footer-section ul {
    list-style: none;
}

.footer-section a {
    color: rgba(255,255,255,0.7);
    text-decoration: none;
    display: block;
    padding: 8px 0;
    transition: color 0.3s;
}

.footer-section a:hover {
    color: var(--white);
}

.footer-bottom {
    border-top: 1px solid rgba(255,255,255,0.1);
    padding-top: 30px;
    text-align: center;
    color: rgba(255,255,255,0.6);
}

/* 响应式设计 */
@media (max-width: 768px) {
    .nav-links {
        display: none;
    }

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

    .advantages-content,
    .feature-detail-content {
        grid-template-columns: 1fr;
    }

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

    .timeline-item {
        grid-template-columns: 1fr;
        margin-left: 0;
    }
}

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

.hero-content {
    animation: fadeInUp 0.8s ease-out;
}