/* ==========================================================================
   云图机场 (Yuntu Airport) - 纯 CSS 原生样式表
   极致秒开 | 科技暗黑风 | 全响应式适配
   ========================================================================== */

/* 1. 变量定义 */
:root {
    --bg-primary: #0b0f19;
    --bg-secondary: #131b2e;
    --bg-card: #1a233a;
    --bg-card-hover: #222d4a;
    --text-main: #f1f5f9;
    --text-muted: #94a3b8;
    --text-dim: #64748b;
    --accent-blue: #38bdf8;
    --accent-indigo: #6366f1;
    --accent-cyan: #06b6d4;
    --accent-purple: #a855f7;
    --accent-emerald: #10b981;
    --gradient-primary: linear-gradient(135deg, #38bdf8 0%, #6366f1 100%);
    --gradient-accent: linear-gradient(135deg, #a855f7 0%, #6366f1 100%);
    --gradient-emerald: linear-gradient(135deg, #10b981 0%, #06b6d4 100%);
    --border-color: rgba(255, 255, 255, 0.08);
    --border-glow: rgba(56, 189, 248, 0.3);
    --radius-sm: 8px;
    --radius-md: 14px;
    --radius-lg: 20px;
    --shadow-subtle: 0 10px 30px -10px rgba(0, 0, 0, 0.5);
    --shadow-glow: 0 0 25px rgba(56, 189, 248, 0.25);
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --max-width: 1200px;
}

/* 2. 基础重置 */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol";
    background-color: var(--bg-primary);
    color: var(--text-main);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
}

body {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    overflow-x: hidden;
}

a {
    color: inherit;
    text-decoration: none;
    transition: var(--transition);
}

ul {
    list-style: none;
}

/* 3. 通用容器与布局 */
.container {
    width: 100%;
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 24px;
}

.section {
    padding: 90px 0;
    position: relative;
}

.section-title {
    text-align: center;
    font-size: 2.25rem;
    font-weight: 800;
    margin-bottom: 16px;
    background: linear-gradient(135deg, #ffffff 30%, #94a3b8 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    letter-spacing: -0.02em;
}

.section-subtitle {
    text-align: center;
    font-size: 1.1rem;
    color: var(--text-muted);
    max-width: 650px;
    margin: 0 auto 56px auto;
}

/* 4. 按钮与 Call To Action 规范 */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 14px 32px;
    font-size: 1rem;
    font-weight: 700;
    border-radius: 9999px;
    cursor: pointer;
    transition: var(--transition);
    border: none;
    text-align: center;
    gap: 8px;
    white-space: nowrap;
}

.btn-primary {
    background: var(--gradient-primary);
    color: #ffffff;
    box-shadow: 0 4px 20px rgba(56, 189, 248, 0.35);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 30px rgba(56, 189, 248, 0.5);
    filter: brightness(1.1);
}

.btn-secondary {
    background: rgba(255, 255, 255, 0.06);
    color: var(--text-main);
    border: 1px solid var(--border-color);
}

.btn-secondary:hover {
    background: rgba(255, 255, 255, 0.12);
    border-color: var(--text-muted);
    transform: translateY(-2px);
}

.btn-lg {
    padding: 16px 40px;
    font-size: 1.125rem;
}

.btn-block {
    width: 100%;
}

/* 5. 导航栏 Header */
.header {
    position: sticky;
    top: 0;
    z-index: 1000;
    background: rgba(11, 15, 25, 0.85);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--border-color);
    height: 76px;
    display: flex;
    align-items: center;
}

.header .container {
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.logo {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 1.4rem;
    font-weight: 800;
    color: var(--text-main);
    letter-spacing: -0.01em;
}

.logo-icon {
    width: 36px;
    height: 36px;
    background: var(--gradient-primary);
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: 900;
    box-shadow: var(--shadow-glow);
}

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

.nav-links a {
    color: var(--text-muted);
    font-weight: 500;
    font-size: 0.95rem;
}

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

.nav-actions {
    display: flex;
    align-items: center;
    gap: 16px;
}

/* 6. 主视觉区 Hero Section */
.hero {
    padding: 100px 0 80px 0;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: "";
    position: absolute;
    top: -20%;
    left: 50%;
    transform: translateX(-50%);
    width: 800px;
    height: 400px;
    background: radial-gradient(ellipse at center, rgba(56, 189, 248, 0.15) 0%, rgba(99, 102, 241, 0.05) 50%, transparent 70%);
    pointer-events: none;
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 6px 16px;
    border-radius: 9999px;
    background: rgba(56, 189, 248, 0.1);
    border: 1px solid rgba(56, 189, 248, 0.25);
    color: var(--accent-blue);
    font-size: 0.875rem;
    font-weight: 600;
    margin-bottom: 24px;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 900;
    line-height: 1.15;
    margin-bottom: 24px;
    letter-spacing: -0.03em;
}

.hero-title span {
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero-subtitle {
    font-size: 1.25rem;
    color: var(--text-muted);
    max-width: 720px;
    margin: 0 auto 40px auto;
}

.hero-cta {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 20px;
    margin-bottom: 50px;
}

.hero-stats {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 24px;
    max-width: 900px;
    margin: 0 auto;
    padding-top: 40px;
    border-top: 1px solid var(--border-color);
}

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

.stat-number {
    font-size: 1.8rem;
    font-weight: 800;
    color: var(--accent-blue);
    margin-bottom: 4px;
}

.stat-label {
    font-size: 0.875rem;
    color: var(--text-muted);
}

/* 7. 产品核心优势 Features Grid */
.features-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 28px;
}

.feature-card {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    padding: 36px 28px;
    border-radius: var(--radius-md);
    transition: var(--transition);
}

.feature-card:hover {
    transform: translateY(-5px);
    border-color: var(--border-glow);
    box-shadow: var(--shadow-subtle);
    background: var(--bg-card-hover);
}

.feature-icon {
    width: 52px;
    height: 52px;
    border-radius: 12px;
    background: rgba(56, 189, 248, 0.1);
    color: var(--accent-blue);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    margin-bottom: 20px;
}

.feature-title {
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: 12px;
    color: var(--text-main);
}

.feature-desc {
    color: var(--text-muted);
    font-size: 0.95rem;
    line-height: 1.6;
}

/* 8. 流媒体与 AI 支持 Media & AI Support */
.media-section {
    background: rgba(19, 27, 46, 0.5);
    border-top: 1px solid var(--border-color);
    border-bottom: 1px solid var(--border-color);
}

.media-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 32px;
}

.media-box {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 36px;
}

.media-box-title {
    font-size: 1.35rem;
    font-weight: 800;
    margin-bottom: 12px;
    display: flex;
    align-items: center;
    gap: 12px;
}

.media-box-title.ai {
    color: var(--accent-purple);
}

.media-box-title.streaming {
    color: var(--accent-cyan);
}

.media-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    margin-top: 24px;
}

.tag-pill {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 8px 16px;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--border-color);
    border-radius: 9999px;
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-main);
}

.tag-pill:hover {
    border-color: var(--accent-blue);
    background: rgba(56, 189, 248, 0.1);
}

/* 9. 套餐价格对比表 Pricing Section */
.pricing-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 24px;
    align-items: stretch;
}

.pricing-card {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 32px 24px;
    display: flex;
    flex-direction: column;
    position: relative;
    transition: var(--transition);
}

.pricing-card:hover {
    transform: translateY(-6px);
    border-color: rgba(56, 189, 248, 0.4);
    box-shadow: 0 12px 30px rgba(0, 0, 0, 0.4);
}

.pricing-card.featured {
    background: linear-gradient(180deg, #1e293b 0%, #0f172a 100%);
    border: 2px solid var(--accent-blue);
    box-shadow: var(--shadow-glow);
}

.popular-badge {
    position: absolute;
    top: -14px;
    left: 50%;
    transform: translateX(-50%);
    background: var(--gradient-primary);
    color: #ffffff;
    font-size: 0.75rem;
    font-weight: 800;
    padding: 4px 16px;
    border-radius: 9999px;
    letter-spacing: 0.05em;
    text-transform: uppercase;
}

.plan-name {
    font-size: 1.25rem;
    font-weight: 800;
    margin-bottom: 8px;
}

.plan-desc {
    font-size: 0.875rem;
    color: var(--text-muted);
    margin-bottom: 24px;
    min-height: 42px;
}

.plan-price {
    font-size: 2.5rem;
    font-weight: 900;
    color: var(--text-main);
    margin-bottom: 24px;
    display: flex;
    align-items: baseline;
    gap: 4px;
}

.plan-price span {
    font-size: 1rem;
    font-weight: 500;
    color: var(--text-muted);
}

.plan-features {
    margin-bottom: 32px;
    flex-grow: 1;
}

.plan-features li {
    font-size: 0.9rem;
    color: var(--text-muted);
    margin-bottom: 12px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.plan-features li::before {
    content: "✓";
    color: var(--accent-emerald);
    font-weight: 900;
}

/* 10. 用户评价 Testimonials Section */
.testimonials-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 28px;
}

.testimonial-card {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 28px;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
}

.user-comment {
    font-size: 0.95rem;
    color: var(--text-muted);
    line-height: 1.7;
    margin-bottom: 20px;
    font-style: italic;
}

.user-profile {
    display: flex;
    align-items: center;
    gap: 12px;
}

.avatar {
    width: 44px;
    height: 44px;
    border-radius: 50%;
    background: var(--gradient-accent);
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 800;
    color: white;
}

.user-info .name {
    font-weight: 700;
    font-size: 0.95rem;
    color: var(--text-main);
}

.user-info .role {
    font-size: 0.8rem;
    color: var(--text-dim);
}

/* 11. 常见问题 FAQ Section (纯原生 HTML details/summary) */
.faq-list {
    max-width: 800px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: 16px;
}

details {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 20px 24px;
    transition: var(--transition);
}

details[open] {
    border-color: var(--border-glow);
    background: var(--bg-card);
}

summary {
    font-size: 1.1rem;
    font-weight: 700;
    cursor: pointer;
    color: var(--text-main);
    list-style: none;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

summary::-webkit-details-marker {
    display: none;
}

summary::after {
    content: "+";
    font-size: 1.4rem;
    font-weight: 400;
    color: var(--accent-blue);
    transition: var(--transition);
}

details[open] summary::after {
    content: "−";
    transform: rotate(180deg);
}

.faq-answer {
    margin-top: 16px;
    padding-top: 16px;
    border-top: 1px solid var(--border-color);
    color: var(--text-muted);
    font-size: 0.95rem;
    line-height: 1.7;
}

/* 12. 页脚 Footer - 严格保留 4 个链接 */
.footer {
    background: #070a12;
    border-top: 1px solid var(--border-color);
    padding: 60px 0 40px 0;
    margin-top: auto;
}

.footer-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 32px;
    text-align: center;
}

.footer-nav {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 40px;
    flex-wrap: wrap;
}

.footer-nav a {
    color: var(--text-muted);
    font-size: 1rem;
    font-weight: 600;
    transition: var(--transition);
    padding: 6px 12px;
    border-radius: var(--radius-sm);
}

.footer-nav a:hover {
    color: var(--accent-blue);
    background: rgba(56, 189, 248, 0.08);
}

.footer-copyright {
    color: var(--text-dim);
    font-size: 0.875rem;
}

/* 13. 通用子页面样式 (About, Terms, Privacy, Sitemap) */
.page-container {
    max-width: 900px;
    margin: 60px auto;
    padding: 40px;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-subtle);
}

.page-header {
    margin-bottom: 40px;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 24px;
}

.page-title {
    font-size: 2.25rem;
    font-weight: 800;
    margin-bottom: 12px;
    color: var(--text-main);
}

.page-updated {
    font-size: 0.875rem;
    color: var(--text-dim);
}

.content-block {
    margin-bottom: 36px;
}

.content-block h2 {
    font-size: 1.4rem;
    font-weight: 700;
    color: var(--accent-blue);
    margin-bottom: 16px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.content-block p {
    color: var(--text-muted);
    margin-bottom: 16px;
    line-height: 1.8;
    font-size: 1rem;
}

.content-block ul {
    margin-left: 24px;
    margin-bottom: 16px;
}

.content-block li {
    color: var(--text-muted);
    margin-bottom: 8px;
    list-style-type: disc;
    line-height: 1.7;
}

/* 14. 响应式适配 @media (手机端与平板) */
@media (max-width: 1024px) {
    .hero-title {
        font-size: 2.75rem;
    }
    
    .features-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .pricing-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 768px) {
    .header {
        height: 64px;
    }

    .nav-links {
        display: none; /* 移动端精简导航 */
    }

    .hero {
        padding: 60px 0 40px 0;
    }

    .hero-title {
        font-size: 2rem;
    }

    .hero-subtitle {
        font-size: 1rem;
    }

    .hero-cta {
        flex-direction: column;
        width: 100%;
    }

    .hero-cta .btn {
        width: 100%;
    }

    .hero-stats {
        grid-template-columns: repeat(2, 1fr);
        gap: 16px;
    }

    .section {
        padding: 60px 0;
    }

    .section-title {
        font-size: 1.75rem;
    }

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

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

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

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

    .footer-nav {
        flex-direction: column;
        gap: 16px;
    }

    .page-container {
        margin: 20px 16px;
        padding: 24px;
    }

    .page-title {
        font-size: 1.75rem;
    }
}

/* 15. 推荐资讯网格卡片与文章页样式 (High-tech Article Grid Cards) */
.articles-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 32px;
    margin-top: 40px;
}

.article-card {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 30px;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.article-card::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: var(--gradient-primary);
    opacity: 0;
    transition: var(--transition);
}

.article-card:hover {
    transform: translateY(-6px);
    border-color: var(--border-glow);
    box-shadow: 0 12px 30px rgba(0, 0, 0, 0.4);
}

.article-card:hover::before {
    opacity: 1;
}

.article-card-tag {
    display: inline-block;
    padding: 4px 12px;
    border-radius: 9999px;
    background: rgba(56, 189, 248, 0.1);
    color: var(--accent-blue);
    font-size: 0.8rem;
    font-weight: 700;
    margin-bottom: 16px;
    align-self: flex-start;
}

.article-card-title {
    font-size: 1.2rem;
    font-weight: 800;
    margin-bottom: 14px;
    line-height: 1.4;
    color: var(--text-main);
}

.article-card-title a {
    color: var(--text-main);
}

.article-card-title a:hover {
    color: var(--accent-blue);
}

.article-card-excerpt {
    font-size: 0.9rem;
    color: var(--text-muted);
    line-height: 1.6;
    margin-bottom: 24px;
    flex-grow: 1;
}

.article-card-footer {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding-top: 16px;
    border-top: 1px solid var(--border-color);
    font-size: 0.85rem;
    color: var(--text-dim);
}

.btn-read-more {
    color: var(--accent-cyan);
    font-weight: 700;
    display: inline-flex;
    align-items: center;
    gap: 4px;
}

.btn-read-more:hover {
    color: var(--accent-blue);
    transform: translateX(4px);
}

/* 文章详情页专用样式 */
.article-detail-container {
    max-width: 920px;
    margin: 40px auto 80px auto;
    padding: 48px;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-subtle);
}

.article-detail-title {
    font-size: 2.2rem;
    font-weight: 900;
    line-height: 1.3;
    margin-bottom: 20px;
    background: linear-gradient(135deg, #ffffff 30%, #38bdf8 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.article-detail-meta {
    display: flex;
    align-items: center;
    gap: 20px;
    padding-bottom: 24px;
    margin-bottom: 36px;
    border-bottom: 1px solid var(--border-color);
    color: var(--text-dim);
    font-size: 0.9rem;
}

.article-body {
    color: var(--text-muted);
    font-size: 1.05rem;
    line-height: 1.85;
}

.article-body h2 {
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--accent-blue);
    margin: 36px 0 16px 0;
    padding-left: 12px;
    border-left: 4px solid var(--accent-cyan);
}

.article-body h3 {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-main);
    margin: 24px 0 12px 0;
}

.article-body p {
    margin-bottom: 20px;
}

.article-body ul, .article-body ol {
    margin: 0 0 20px 24px;
}

.article-body li {
    margin-bottom: 8px;
}

.article-body blockquote {
    background: rgba(56, 189, 248, 0.06);
    border-left: 4px solid var(--accent-blue);
    padding: 18px 24px;
    border-radius: var(--radius-sm);
    margin: 24px 0;
    font-style: italic;
    color: var(--text-main);
}

.seo-pbn-box {
    background: rgba(99, 102, 241, 0.08);
    border: 1px dashed rgba(99, 102, 241, 0.3);
    padding: 20px 24px;
    border-radius: var(--radius-md);
    margin: 32px 0;
}

.seo-pbn-box p {
    margin-bottom: 8px;
    font-size: 0.95rem;
}

.seo-pbn-box a {
    color: var(--accent-blue);
    font-weight: 700;
    text-decoration: underline;
}

.seo-pbn-box a:hover {
    color: var(--accent-cyan);
}

.btn-back {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 12px 28px;
    background: rgba(255, 255, 255, 0.06);
    color: var(--text-main);
    border: 1px solid var(--border-color);
    border-radius: 9999px;
    font-weight: 600;
    margin-bottom: 32px;
    transition: var(--transition);
}

.btn-back:hover {
    background: rgba(56, 189, 248, 0.15);
    border-color: var(--accent-blue);
    color: var(--accent-blue);
    transform: translateX(-4px);
}

@media (max-width: 1024px) {
    .articles-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 768px) {
    .articles-grid {
        grid-template-columns: 1fr;
    }
    .article-detail-container {
        padding: 24px;
        margin: 20px 12px;
    }
    .article-detail-title {
        font-size: 1.6rem;
    }
}