/* style.css */
:root {
    --primary: #2563EB;
    --primary-hover: #1D4ED8;
    --secondary: #F59E0B;
    --text-main: #1F2937;
    --text-muted: #6B7280;
    --bg-main: #F9FAFB;
    --bg-card: #FFFFFF;
    --border-color: #E5E7EB;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --radius: 12px;
}

html {
    scroll-behavior: smooth;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    color: var(--text-main);
    background-color: var(--bg-main);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
}

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

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

.text-center { text-align: center; }
.text-white { color: #fff !important; }

/* Buttons */
.btn {
    display: inline-block;
    padding: 10px 24px;
    font-size: 16px;
    font-weight: 500;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.2s ease;
    text-align: center;
}
.btn-primary {
    background-color: var(--primary);
    color: #fff;
    border: none;
}
.btn-primary:hover {
    background-color: var(--primary-hover);
    color: #fff;
}
.btn-outline {
    background-color: transparent;
    color: var(--primary);
    border: 1px solid var(--primary);
}
.btn-outline:hover {
    background-color: var(--primary);
    color: #fff;
}
.btn-light {
    background-color: #fff;
    color: var(--primary);
}
.btn-light:hover {
    background-color: #f3f4f6;
}
.btn-large {
    padding: 14px 36px;
    font-size: 18px;
}
.btn-block {
    display: block;
    width: 100%;
}

/* Header & Nav */
.header, .navbar {
    background-color: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(12px);
    border: 1px solid var(--border-color);
    border-radius: 50px;
    position: sticky;
    top: 15px;
    z-index: 100;
    margin: 15px auto;
    width: 95%;
    max-width: 1200px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.05);
}
.header .nav-wrapper, .navbar .nav-wrapper {
    padding: 0 30px;
}
.nav-wrapper {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}
.logo {
    font-size: 24px;
    font-weight: 700;
    color: var(--primary);
}
.main-nav {
    display: flex;
    gap: 24px;
}
.main-nav a {
    color: var(--text-main);
    font-weight: 500;
    transition: color 0.2s;
}
.main-nav a:hover {
    color: var(--primary);
}

/* Sections */
section {
    padding: 80px 0;
}
.section-title {
    text-align: center;
    font-size: 32px;
    font-weight: 700;
    margin-bottom: 48px;
}

/* Hero Section (Left-Right Layout) */
.hero {
    background: linear-gradient(180deg, #FFFFFF 0%, #F3F4F6 100%);
    padding: 100px 0 120px;
    overflow: hidden;
}
.hero-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 40px;
}
.hero-content {
    flex: 1;
    max-width: 600px;
}
.headline {
    font-size: 44px;
    font-weight: 800;
    margin-bottom: 24px;
    line-height: 1.25;
}
.subheadline {
    font-size: 20px;
    color: var(--text-muted);
    margin-bottom: 40px;
}
.hero-actions {
    display: flex;
    gap: 16px;
}

/* Hero Visual & Animations */
.hero-visual {
    flex: 1;
    position: relative;
    height: 400px;
    display: flex;
    align-items: center;
    justify-content: center;
}
.floating-cards {
    position: relative;
    width: 100%;
    height: 100%;
}
.float-card {
    position: absolute;
    background: var(--bg-card);
    padding: 16px 24px;
    border-radius: var(--radius);
    box-shadow: var(--shadow-lg);
    font-weight: 600;
    color: var(--text-main);
    display: flex;
    align-items: center;
    gap: 12px;
    border: 1px solid rgba(255,255,255,0.5);
    backdrop-filter: blur(4px);
    animation: float 6s ease-in-out infinite;
}
.float-card .icon {
    font-size: 24px;
}

/* Position and distinct animation delays for dynamic cards */
.card-1 { top: 10%; left: 10%; animation-delay: 0s; }
.card-2 { top: 35%; right: 5%; animation-delay: -1.5s; }
.card-3 { bottom: 20%; left: 15%; animation-delay: -3s; }
.card-4 { bottom: 5%; right: 20%; animation-delay: -4.5s; }

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

/* Grid Layouts */
.grid-3 {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 32px;
}

/* Cards */
.card {
    background: var(--bg-card);
    border-radius: var(--radius);
    padding: 32px;
    box-shadow: var(--shadow-md);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}
.card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}
.features .icon {
    font-size: 48px;
    margin-bottom: 20px;
}
.features h3 {
    font-size: 20px;
    margin-bottom: 12px;
}
.features p {
    color: var(--text-muted);
}

/* Streaming & AI */
.bg-gradient {
    background: linear-gradient(135deg, var(--primary) 0%, #8B5CF6 100%);
}
.tags-container {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 12px;
    margin-top: 32px;
}
.tag {
    background: rgba(255, 255, 255, 0.2);
    color: #fff;
    padding: 8px 16px;
    border-radius: 20px;
    font-weight: 500;
    backdrop-filter: blur(4px);
}

/* Pricing */
.pricing-card {
    display: flex;
    flex-direction: column;
    position: relative;
    border: 1px solid var(--border-color);
}
.pricing-card.popular {
    border-color: var(--primary);
    box-shadow: var(--shadow-lg);
}
.popular-badge {
    position: absolute;
    top: -14px;
    left: 50%;
    transform: translateX(-50%);
    background: var(--secondary);
    color: #fff;
    padding: 4px 16px;
    border-radius: 20px;
    font-size: 14px;
    font-weight: 600;
}
.price {
    font-size: 48px;
    font-weight: 800;
    margin: 24px 0;
}
.currency { font-size: 24px; vertical-align: top; }
.period { font-size: 16px; color: var(--text-muted); font-weight: normal; }
.features-list {
    list-style: none;
    margin-bottom: 32px;
    flex-grow: 1;
}
.features-list li {
    padding: 12px 0;
    border-bottom: 1px solid var(--border-color);
    color: var(--text-muted);
}
.features-list li:last-child {
    border-bottom: none;
}
.features-list li::before {
    content: "✓";
    color: var(--primary);
    font-weight: bold;
    margin-right: 8px;
}

/* Reviews */
.review-card {
    display: flex;
    flex-direction: column;
    justify-content: space-between;
}
.stars {
    margin-bottom: 16px;
}
.review-text {
    font-style: italic;
    margin-bottom: 24px;
    flex-grow: 1;
}
.reviewer {
    font-weight: 600;
    color: var(--primary);
}

/* Articles / Blog Section */
.bg-light { background-color: #f1f5f9; }
.article-card {
    display: block;
    background: var(--bg-card);
    border-radius: var(--radius);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    text-decoration: none;
    color: var(--text-main);
    border: 1px solid var(--border-color);
}
.article-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}
.article-content {
    padding: 24px;
}
.tag-sm {
    display: inline-block;
    background: #e0e7ff;
    color: var(--primary);
    padding: 4px 10px;
    border-radius: 4px;
    font-size: 12px;
    font-weight: 600;
    margin-bottom: 12px;
}
.article-content h3 {
    font-size: 18px;
    margin-bottom: 12px;
    color: var(--text-main);
    line-height: 1.4;
}
.article-content p {
    color: var(--text-muted);
    font-size: 14px;
    margin-bottom: 16px;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}
.read-more {
    color: var(--primary);
    font-weight: 600;
    font-size: 14px;
}
.article-card:hover .read-more {
    text-decoration: underline;
}

/* FAQ */
.faq-list {
    max-width: 800px;
    margin: 0 auto;
}
.faq-item {
    background: var(--bg-card);
    padding: 24px;
    border-radius: var(--radius);
    margin-bottom: 16px;
    box-shadow: var(--shadow-sm);
}
.faq-item h4 {
    font-size: 18px;
    margin-bottom: 12px;
}
.faq-item p {
    color: var(--text-muted);
}

/* Footer */
.footer {
    background-color: #111827;
    color: #9CA3AF;
    padding: 40px 0;
    text-align: center;
}
.footer-links {
    display: flex;
    justify-content: center;
    gap: 24px;
    margin-bottom: 24px;
    flex-wrap: wrap;
}
.footer-links a {
    color: #D1D5DB;
}
.footer-links a:hover {
    color: #fff;
}

/* Mobile Responsive */
@media (max-width: 900px) {
    .hero-container {
        flex-direction: column;
        text-align: center;
    }
    .hero-actions {
        justify-content: center;
    }
    .main-nav {
        display: none; /* simple mobile nav hide for purely CSS demo */
    }
}
@media (max-width: 768px) {
    .headline { font-size: 32px; }
    .subheadline { font-size: 18px; }
    section { padding: 50px 0; }
    .grid-3 { grid-template-columns: 1fr; }
    .hero-visual {
        height: 300px;
    }
    .card-1 { top: 5%; left: 0; }
    .card-2 { top: 30%; right: 0; }
    .card-3 { bottom: 25%; left: 5%; }
    .card-4 { bottom: 0; right: 5%; }
}

/* 文章底部 CTA 卡片 (修复缺失的样式) */
.cta-card {
    background: linear-gradient(135deg, #f8fafc 0%, #e0e7ff 100%);
    border: 1px solid #e2e8f0;
    border-radius: 12px;
    padding: 40px 30px;
    text-align: center;
    margin-top: 50px;
    box-shadow: 0 10px 30px rgba(37, 99, 235, 0.08);
}
.cta-card h3 {
    font-size: 1.5rem !important;
    color: #0f172a !important;
    margin-bottom: 15px !important;
    font-weight: 800 !important;
    border: none !important;
    padding-bottom: 0 !important;
}
.cta-card p {
    color: #475569 !important;
    margin-bottom: 25px !important;
    font-size: 1.05rem !important;
}
.article-content a.btn, .cta-card a.btn {
    color: #ffffff !important;
    text-decoration: none !important;
    display: inline-block;
    padding: 12px 28px;
    border-radius: 8px;
    font-weight: 600;
}