/* ===== 基础样式 ===== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #0088cc;
    --secondary-color: #34b7f1;
    --accent-color: #2aabee;
    --bg-color: #ffffff;
    --bg-secondary: #f5f7fa;
    --bg-dark: #1a1d23;
    --bg-darker: #0f1115;
    --text-primary: #1a1d23;
    --text-secondary: #5e6d82;
    --text-light: #8b95a5;
    --border-color: #e1e8ed;
    --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.12);
    --shadow-xl: 0 16px 40px rgba(0, 0, 0, 0.15);
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 24px;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Helvetica Neue', Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
}

.container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 24px;
}

/* ===== 导航栏 ===== */
.navbar {
    background-color: var(--bg-color);
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    transition: var(--transition);
    border-bottom: 1px solid transparent;
}

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

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

.nav-logo {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-primary);
    text-decoration: none;
}

.logo-icon {
    width: 36px;
    height: 36px;
    color: var(--primary-color);
}

.nav-menu {
    display: flex;
    gap: 8px;
}

.nav-link {
    color: var(--text-primary);
    text-decoration: none;
    font-weight: 500;
    padding: 10px 20px;
    border-radius: var(--radius-sm);
    transition: var(--transition);
    position: relative;
}

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

.nav-link.active {
    color: var(--primary-color);
    background-color: rgba(0, 136, 204, 0.1);
}

.theme-toggle {
    background: var(--bg-secondary);
    border: none;
    border-radius: 50%;
    width: 44px;
    height: 44px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
    margin-left: 16px;
}

.theme-toggle:hover {
    background-color: var(--border-color);
}

.sun-icon, .moon-icon {
    width: 22px;
    height: 22px;
}

.sun-icon {
    display: none;
}

.dark-mode .sun-icon {
    display: block;
    color: var(--text-primary);
}

.moon-icon {
    display: block;
    color: var(--text-primary);
}

.dark-mode .moon-icon {
    display: none;
}

.mobile-menu-btn {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
}

.mobile-menu-btn span {
    width: 24px;
    height: 2px;
    background-color: var(--text-primary);
    transition: var(--transition);
}

/* ===== 首屏横幅 ===== */
.hero {
    padding: 160px 0 120px;
    background: var(--bg-dark);
    color: white;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: 
        radial-gradient(circle at 20% 50%, rgba(0, 136, 204, 0.15) 0%, transparent 50%),
        radial-gradient(circle at 80% 20%, rgba(52, 183, 241, 0.1) 0%, transparent 40%),
        radial-gradient(circle at 40% 80%, rgba(42, 171, 238, 0.1) 0%, transparent 40%);
}

.hero .container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 80px;
    align-items: center;
    position: relative;
    z-index: 1;
}

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

.hero-badge {
    display: inline-block;
    padding: 8px 16px;
    background: rgba(0, 136, 204, 0.2);
    border: 1px solid rgba(0, 136, 204, 0.3);
    border-radius: var(--radius-xl);
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--secondary-color);
    margin-bottom: 24px;
}

.hero-title {
    font-size: 4.5rem;
    font-weight: 800;
    line-height: 1.1;
    margin-bottom: 24px;
    background: linear-gradient(135deg, #ffffff 0%, #a8d8ff 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: 1.5rem;
    font-weight: 500;
    margin-bottom: 16px;
    color: rgba(255, 255, 255, 0.9);
}

.hero-description {
    font-size: 1.125rem;
    margin-bottom: 40px;
    color: rgba(255, 255, 255, 0.7);
    line-height: 1.8;
}

.hero-actions {
    display: flex;
    gap: 16px;
    flex-wrap: wrap;
}

.hero-image {
    animation: fadeIn 1s ease 0.2s both;
}

.hero-plane {
    width: 100%;
    height: auto;
    max-width: 500px;
    margin: 0 auto;
    animation: float 6s ease-in-out infinite;
}

.hero-stats {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 32px;
    margin-top: 60px;
    padding-top: 40px;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

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

.stat-number {
    font-size: 2.5rem;
    font-weight: 800;
    color: var(--primary-color);
    display: block;
    margin-bottom: 4px;
}

.stat-label {
    font-size: 0.9rem;
    color: rgba(255, 255, 255, 0.6);
}

@keyframes float {
    0%, 100% { transform: translateY(0px) rotate(0deg); }
    50% { transform: translateY(-15px) rotate(2deg); }
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(40px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* ===== 按钮样式 ===== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 14px 32px;
    border-radius: var(--radius-md);
    font-weight: 600;
    text-decoration: none;
    cursor: pointer;
    transition: var(--transition);
    border: none;
    font-size: 1rem;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    box-shadow: 0 4px 15px rgba(0, 136, 204, 0.4);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(0, 136, 204, 0.5);
}

.btn-secondary {
    background: rgba(255, 255, 255, 0.1);
    color: white;
    border: 1px solid rgba(255, 255, 255, 0.2);
    backdrop-filter: blur(10px);
}

.btn-secondary:hover {
    background: rgba(255, 255, 255, 0.15);
    border-color: rgba(255, 255, 255, 0.3);
}

.btn-light {
    background: white;
    color: var(--primary-color);
    box-shadow: var(--shadow-md);
}

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

.btn-large {
    padding: 18px 48px;
    font-size: 1.125rem;
}

.btn svg {
    width: 20px;
    height: 20px;
}

/* ===== 特性区域 ===== */
.features {
    padding: 120px 0;
    background-color: var(--bg-secondary);
}

.section-header {
    text-align: center;
    margin-bottom: 80px;
}

.section-title {
    font-size: 3rem;
    font-weight: 800;
    margin-bottom: 16px;
    color: var(--text-primary);
}

.section-subtitle {
    font-size: 1.25rem;
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 32px;
}

.feature-card {
    background-color: var(--bg-color);
    padding: 40px;
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
    border: 1px solid var(--border-color);
}

.feature-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-xl);
    border-color: var(--primary-color);
}

.feature-icon {
    width: 64px;
    height: 64px;
    margin-bottom: 24px;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
}

.feature-icon svg {
    width: 32px;
    height: 32px;
    color: white;
}

.feature-card h3 {
    font-size: 1.5rem;
    margin-bottom: 12px;
    color: var(--text-primary);
    font-weight: 700;
}

.feature-card p {
    color: var(--text-secondary);
    line-height: 1.8;
}

/* ===== 下载区域 ===== */
.download {
    padding: 120px 0;
    background-color: var(--bg-color);
}

.download-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 32px;
    margin-top: 60px;
}

.download-card {
    background-color: var(--bg-secondary);
    padding: 48px 40px;
    border-radius: var(--radius-xl);
    text-align: center;
    transition: var(--transition);
    border: 2px solid transparent;
}

.download-card:hover {
    border-color: var(--primary-color);
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.download-icon {
    width: 80px;
    height: 80px;
    margin: 0 auto 24px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.download-icon svg {
    width: 64px;
    height: 64px;
    color: var(--text-primary);
}

.download-card h3 {
    font-size: 1.5rem;
    margin-bottom: 12px;
    color: var(--text-primary);
}

.download-card p {
    color: var(--text-secondary);
    margin-bottom: 24px;
}

/* ===== 常见问题 ===== */
.faq {
    padding: 120px 0;
    background-color: var(--bg-secondary);
}

.faq-list {
    max-width: 800px;
    margin: 0 auto;
}

.faq-item {
    background-color: var(--bg-color);
    border-radius: var(--radius-lg);
    margin-bottom: 16px;
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
    border: 1px solid var(--border-color);
}

.faq-item:hover {
    box-shadow: var(--shadow-md);
}

.faq-question {
    padding: 24px 32px;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-weight: 600;
    color: var(--text-primary);
    font-size: 1.125rem;
}

.faq-icon {
    width: 24px;
    height: 24px;
    transition: var(--transition);
    flex-shrink: 0;
}

.faq-item.active .faq-icon {
    transform: rotate(180deg);
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease;
    padding: 0 32px;
}

.faq-item.active .faq-answer {
    max-height: 500px;
    padding: 0 32px 24px;
}

.faq-answer p {
    color: var(--text-secondary);
    line-height: 1.8;
    padding-top: 16px;
    border-top: 1px solid var(--border-color);
}

/* ===== 底部行动号召 ===== */
.cta {
    padding: 120px 0;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    text-align: center;
    color: white;
    position: relative;
    overflow: hidden;
}

.cta::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><circle cx="50" cy="50" r="2" fill="rgba(255,255,255,0.1)"/></svg>');
    background-size: 40px 40px;
}

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

.cta h2 {
    font-size: 3rem;
    margin-bottom: 16px;
    font-weight: 800;
}

.cta p {
    font-size: 1.25rem;
    margin-bottom: 40px;
    opacity: 0.9;
}

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

/* ===== 页脚 ===== */
.footer {
    background-color: var(--bg-dark);
    border-top: 1px solid rgba(255, 255, 255, 0.05);
    padding: 80px 0 40px;
    color: white;
}

.footer-content {
    display: grid;
    grid-template-columns: 1.5fr 1fr 1fr 1fr;
    gap: 48px;
    margin-bottom: 60px;
}

.footer-brand {
    max-width: 300px;
}

.footer-brand h4 {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 16px;
}

.footer-brand p {
    color: rgba(255, 255, 255, 0.6);
    line-height: 1.8;
}

.footer-section h4 {
    font-size: 1.125rem;
    margin-bottom: 24px;
    color: white;
    font-weight: 600;
}

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

.footer-section ul li {
    margin-bottom: 12px;
}

.footer-section ul li a {
    color: rgba(255, 255, 255, 0.7);
    text-decoration: none;
    transition: var(--transition);
    display: inline-block;
}

.footer-section ul li a:hover {
    color: var(--secondary-color);
    transform: translateX(5px);
}

.social-links {
    display: flex;
    gap: 12px;
}

.social-links a {
    width: 44px;
    height: 44px;
    background-color: rgba(255, 255, 255, 0.1);
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
}

.social-links a:hover {
    background-color: var(--primary-color);
    transform: translateY(-3px);
}

.social-links a svg {
    width: 20px;
    height: 20px;
}

.footer-bottom {
    text-align: center;
    padding-top: 40px;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    color: rgba(255, 255, 255, 0.5);
}

/* ===== 响应式设计 ===== */
@media (max-width: 1024px) {
    .hero .container {
        grid-template-columns: 1fr;
        text-align: center;
        gap: 60px;
    }
    
    .hero-title {
        font-size: 3.5rem;
    }
    
    .hero-plane {
        max-width: 400px;
    }
    
    .hero-actions {
        justify-content: center;
    }
    
    .hero-stats {
        grid-template-columns: repeat(3, 1fr);
        gap: 24px;
    }
    
    .nav-menu {
        position: fixed;
        top: 72px;
        left: 0;
        right: 0;
        background-color: var(--bg-color);
        flex-direction: column;
        padding: 24px;
        gap: 8px;
        box-shadow: var(--shadow-xl);
        transform: translateY(-150%);
        transition: var(--transition);
    }
    
    .nav-menu.active {
        transform: translateY(0);
    }
    
    .mobile-menu-btn {
        display: flex;
    }
    
    .footer-content {
        grid-template-columns: 1fr 1fr;
        gap: 40px;
    }
}

@media (max-width: 640px) {
    .hero {
        padding: 140px 0 100px;
    }
    
    .hero-title {
        font-size: 2.5rem;
    }
    
    .hero-subtitle {
        font-size: 1.25rem;
    }
    
    .hero-actions {
        flex-direction: column;
    }
    
    .hero-btn {
        width: 100%;
    }
    
    .section-title {
        font-size: 2rem;
    }
    
    .section-subtitle {
        font-size: 1.125rem;
    }
    
    .features-grid,
    .download-grid {
        grid-template-columns: 1fr;
    }
    
    .hero-stats {
        grid-template-columns: 1fr;
        gap: 32px;
    }
    
    .footer-content {
        grid-template-columns: 1fr;
        gap: 32px;
    }
    
    .faq-question {
        padding: 20px 24px;
        font-size: 1rem;
    }
    
    .faq-answer {
        padding: 0 24px;
    }
    
    .faq-item.active .faq-answer {
        padding: 0 24px 20px;
    }
}