/* 全局样式重置 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary: #0ea5e9;
    --secondary: #06b6d4;
    --accent: #8b5cf6;
    --dark: #0f172a;
    --light: #f1f5f9;
    --text: #334155;
    --border: #cbd5e1;
    --shadow: 0 1px 3px 0 rgb(0 0 0 / 0.1), 0 1px 2px -1px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    line-height: 1.7;
    color: var(--text);
    background-color: #ffffff;
    overflow-x: hidden;
}

/* 容器 */
.container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 1.5rem;
}

/* 头部 */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(12px);
    z-index: 1000;
    border-bottom: 1px solid rgba(0, 0, 0, 0.05);
}

.header-inner {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.25rem 0;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary);
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.logo i {
    font-size: 1.75rem;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 2rem;
    align-items: center;
}

.nav-link {
    text-decoration: none;
    color: var(--text);
    font-weight: 500;
    transition: var(--transition);
}

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

.btn-primary {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: white;
    padding: 0.75rem 1.5rem;
    border-radius: 9999px;
    text-decoration: none;
    font-weight: 600;
    transition: var(--transition);
    border: none;
    cursor: pointer;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

/* 英雄区域 */
.hero {
    padding: 12rem 0 6rem;
    background: linear-gradient(135deg, #f0f9ff 0%, #fdf2ff 100%);
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -20%;
    width: 800px;
    height: 800px;
    background: radial-gradient(circle, rgba(14, 165, 233, 0.1) 0%, transparent 70%);
    border-radius: 50%;
}

.hero-content {
    text-align: center;
    position: relative;
    z-index: 1;
}

.hero-title {
    font-size: 4rem;
    font-weight: 800;
    line-height: 1.1;
    margin-bottom: 1.5rem;
    background: linear-gradient(135deg, var(--dark) 0%, var(--primary) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: 1.25rem;
    color: #64748b;
    max-width: 640px;
    margin: 0 auto 2.5rem;
}

.hero-buttons {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
}

.btn-secondary {
    background: white;
    color: var(--primary);
    padding: 0.75rem 1.5rem;
    border-radius: 9999px;
    text-decoration: none;
    font-weight: 600;
    border: 2px solid var(--primary);
    transition: var(--transition);
}

.btn-secondary:hover {
    background: var(--primary);
    color: white;
}

/* 特性区域 */
.features {
    padding: 6rem 0;
}

.section-header {
    text-align: center;
    margin-bottom: 4rem;
}

.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    color: var(--dark);
}

.section-description {
    font-size: 1.125rem;
    color: #64748b;
    max-width: 600px;
    margin: 0 auto;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 2rem;
}

.feature-card {
    background: white;
    border: 1px solid var(--border);
    border-radius: 1rem;
    padding: 2rem;
    transition: var(--transition);
}

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

.feature-icon {
    width: 3.5rem;
    height: 3.5rem;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    border-radius: 1rem;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 1.5rem;
    font-size: 1.5rem;
    color: white;
}

.feature-title {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 0.75rem;
    color: var(--dark);
}

.feature-text {
    color: #64748b;
    line-height: 1.7;
}

/* 节点区域 */
.nodes {
    padding: 6rem 0;
    background: #f8fafc;
}

.nodes-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.5rem;
    margin-top: 3rem;
}

.node-card {
    background: white;
    border-radius: 0.75rem;
    padding: 1.5rem;
    border: 1px solid var(--border);
    transition: var(--transition);
}

.node-card:hover {
    border-color: var(--primary);
    box-shadow: var(--shadow);
}

.node-title {
    font-size: 1.125rem;
    font-weight: 600;
    margin-bottom: 0.75rem;
    color: var(--primary);
}

.node-text {
    color: #64748b;
}

/* 下载区域 */
.download {
    padding: 6rem 0;
}

.download-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 1.5rem;
    margin-top: 3rem;
}

.download-card {
    background: white;
    border: 2px solid var(--border);
    border-radius: 1rem;
    padding: 2rem;
    text-align: center;
    transition: var(--transition);
}

.download-card:hover {
    border-color: var(--primary);
    transform: scale(1.02);
}

.download-icon {
    width: 4rem;
    height: 4rem;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 1.5rem;
    font-size: 2rem;
    color: white;
}

.download-title {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: var(--dark);
}

.download-text {
    color: #64748b;
    margin-bottom: 1.5rem;
}

/* 安装步骤 */
.install-steps {
    padding: 6rem 0;
    background: #f8fafc;
}

.steps {
    max-width: 700px;
    margin: 0 auto;
}

.step {
    display: flex;
    gap: 2rem;
    margin-bottom: 3rem;
    position: relative;
}

.step:not(:last-child)::after {
    content: '';
    position: absolute;
    left: 1.5rem;
    top: 3.5rem;
    bottom: -2.5rem;
    width: 2px;
    background: var(--border);
}

.step-number {
    width: 3.5rem;
    height: 3.5rem;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: 700;
    font-size: 1.25rem;
    flex-shrink: 0;
}

.step-content {
    flex: 1;
}

.step-title {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: var(--dark);
}

.step-text {
    color: #64748b;
}

/* FAQ */
.faq {
    padding: 6rem 0;
}

.faq-list {
    max-width: 700px;
    margin: 3rem auto 0;
}

.faq-item {
    border: 1px solid var(--border);
    border-radius: 0.75rem;
    margin-bottom: 1rem;
    overflow: hidden;
}

.faq-question {
    width: 100%;
    padding: 1.25rem 1.5rem;
    background: white;
    border: none;
    text-align: left;
    font-size: 1.125rem;
    font-weight: 600;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    color: var(--dark);
    transition: var(--transition);
}

.faq-question:hover {
    background: #f8fafc;
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease;
    padding: 0 1.5rem;
}

.faq-answer.active {
    padding: 0 1.5rem 1.25rem;
    max-height: 300px;
}

.faq-answer p {
    color: #64748b;
    line-height: 1.7;
}

/* 页脚 */
.footer {
    background: var(--dark);
    color: white;
    padding: 4rem 0 2rem;
}

.footer-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 2rem;
    margin-bottom: 2.5rem;
}

.footer-brand p {
    color: #94a3b8;
    margin-top: 1rem;
}

.footer-title {
    font-size: 1.125rem;
    font-weight: 600;
    margin-bottom: 1.25rem;
}

.footer-links {
    list-style: none;
}

.footer-links li {
    margin-bottom: 0.75rem;
}

.footer-links a {
    color: #94a3b8;
    text-decoration: none;
    transition: var(--transition);
}

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

.footer-bottom {
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    padding-top: 2rem;
    text-align: center;
    color: #94a3b8;
}

/* 响应式 */
@media (max-width: 768px) {
    .hero-title {
        font-size: 2.5rem;
    }
    
    .nav-menu {
        display: none;
    }
    
    .step {
        flex-direction: column;
    }
    
    .step:not(:last-child)::after {
        display: none;
    }
}

/* 动画 */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.fade-in-up {
    animation: fadeInUp 0.6s ease-out;
}