/* Reset and Base Styles - 优化版 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary: #2563eb;
    --primary-hover: #1d4ed8;
    --primary-light: #3b82f6;
    --primary-glow: rgba(37, 99, 235, 0.1);
    --secondary: #64748b;
    --text: #0f172a;
    --text-secondary: #475569;
    --bg: #ffffff;
    --bg-alt: #f8fafc;
    --bg-gradient: linear-gradient(135deg, #f8fafc 0%, #f1f5f9 100%);
    --border: #e2e8f0;
    --border-light: #f1f5f9;
    --accent: #8b5cf6;
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.08), 0 2px 4px -1px rgba(0, 0, 0, 0.04);
    --shadow-lg: 0 10px 25px -5px rgba(0, 0, 0, 0.08), 0 8px 10px -6px rgba(0, 0, 0, 0.04);
    --shadow-xl: 0 20px 40px -10px rgba(0, 0, 0, 0.1);
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 24px;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    color: var(--text);
    line-height: 1.6;
    background-color: var(--bg);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    overflow-x: hidden;
}

.container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 32px;
}

/* Navigation - 现代化设计 */
.navbar {
    background: rgba(255, 255, 255, 0.92);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    padding: 16px 0;
    border-bottom: 1px solid rgba(226, 232, 240, 0.5);
    transition: var(--transition);
}

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

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

.nav-brand h1 {
    font-size: 20px;
    font-weight: 700;
    letter-spacing: -0.02em;
    background: linear-gradient(135deg, var(--primary) 0%, var(--accent) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav-links {
    display: flex;
    gap: 40px;
    align-items: center;
}

.nav-links a:not(.btn) {
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 500;
    font-size: 14px;
    transition: var(--transition);
    position: relative;
    padding: 8px 0;
}

.nav-links a:not(.btn)::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--primary);
    transition: var(--transition);
    border-radius: 2px;
}

.nav-links a:not(.btn):hover {
    color: var(--text);
}

.nav-links a:not(.btn):hover::after {
    width: 100%;
}

/* Buttons - 现代化设计 */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 12px 24px;
    border-radius: var(--radius-sm);
    text-decoration: none;
    font-weight: 600;
    font-size: 14px;
    transition: var(--transition);
    border: none;
    cursor: pointer;
    position: relative;
    overflow: hidden;
}

.btn::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.1);
    transform: translate(-50%, -50%);
    transition: width 0.6s, height 0.6s;
}

.btn:hover::before {
    width: 300px;
    height: 300px;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-light) 100%);
    color: white !important;
    box-shadow: 0 4px 12px rgba(37, 99, 235, 0.2);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(37, 99, 235, 0.3);
}

.btn-secondary {
    background: transparent;
    color: var(--text);
    border: 1.5px solid var(--border);
}

.btn-secondary:hover {
    background: var(--bg-alt);
    border-color: var(--text-secondary);
    transform: translateY(-2px);
}

.btn-outline {
    background: transparent;
    color: var(--text);
    border: 1.5px solid var(--border);
}

.btn-outline:hover {
    background: var(--bg-alt);
    color: var(--text);
    transform: translateY(-2px);
}

.btn-large {
    padding: 16px 32px;
    font-size: 16px;
    border-radius: var(--radius-md);
}

.btn-block {
    display: flex;
    width: 100%;
}

/* Hero Section - 现代化设计 */
.hero {
    background: var(--bg-gradient);
    padding: 160px 0 100px;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 100%;
    background: radial-gradient(circle at 20% 80%, rgba(37, 99, 235, 0.05) 0%, transparent 50%),
                radial-gradient(circle at 80% 20%, rgba(139, 92, 246, 0.05) 0%, transparent 50%);
}

.hero-content {
    max-width: 800px;
    margin: 0 auto;
    text-align: center;
    position: relative;
    z-index: 1;
}

.hero-title {
    font-size: 64px;
    font-weight: 800;
    margin-bottom: 24px;
    line-height: 1.1;
    letter-spacing: -0.03em;
    background: linear-gradient(135deg, var(--text) 0%, var(--text-secondary) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: 22px;
    margin-bottom: 48px;
    color: var(--text-secondary);
    line-height: 1.6;
    font-weight: 400;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.hero-buttons {
    display: flex;
    gap: 16px;
    justify-content: center;
    margin-bottom: 80px;
    flex-wrap: wrap;
}

.hero-stats {
    display: flex;
    justify-content: center;
    gap: 80px;
    padding: 48px 0 0;
    border-top: 1px solid var(--border-light);
    flex-wrap: wrap;
}

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

.stat-number {
    font-size: 40px;
    font-weight: 700;
    margin-bottom: 8px;
    background: linear-gradient(135deg, var(--primary) 0%, var(--accent) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: -0.02em;
}

.stat-label {
    font-size: 14px;
    color: var(--text-secondary);
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

/* Section Styles */
section {
    padding: 100px 0;
}

.section-title {
    font-size: 48px;
    font-weight: 800;
    text-align: center;
    margin-bottom: 20px;
    color: var(--text);
    letter-spacing: -0.02em;
    position: relative;
}

.section-title::after {
    content: '';
    display: block;
    width: 60px;
    height: 4px;
    background: linear-gradient(90deg, var(--primary), var(--accent));
    border-radius: 2px;
    margin: 16px auto;
}

.section-subtitle {
    text-align: center;
    color: var(--text-secondary);
    font-size: 18px;
    margin-bottom: 64px;
    font-weight: 400;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

/* Features Section */
.features {
    background: var(--bg);
    position: relative;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
    gap: 32px;
}

.feature-card {
    background: var(--bg);
    padding: 40px;
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    transition: var(--transition);
    text-align: left;
    position: relative;
    overflow: hidden;
}

.feature-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: linear-gradient(90deg, var(--primary), var(--accent));
    transform: translateX(-100%);
    transition: transform 0.6s;
}

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

.feature-card:hover::before {
    transform: translateX(0);
}

.feature-icon {
    font-size: 40px;
    margin-bottom: 24px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 64px;
    height: 64px;
    background: var(--primary-glow);
    border-radius: var(--radius-md);
}

.feature-card h3 {
    font-size: 20px;
    font-weight: 700;
    margin-bottom: 16px;
    color: var(--text);
    letter-spacing: -0.01em;
}

.feature-card p {
    color: var(--text-secondary);
    line-height: 1.6;
    font-size: 16px;
    font-weight: 400;
}

/* How It Works */
.how-it-works {
    background: var(--bg-gradient);
    position: relative;
}

.steps {
    display: flex;
    justify-content: center;
    align-items: stretch;
    gap: 48px;
    flex-wrap: wrap;
    position: relative;
}

.step {
    flex: 1;
    min-width: 280px;
    text-align: left;
    padding: 40px;
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    transition: var(--transition);
    position: relative;
    z-index: 1;
}

.step:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.step-number {
    width: 56px;
    height: 56px;
    background: linear-gradient(135deg, var(--primary) 0%, var(--accent) 100%);
    color: white;
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
    font-weight: 700;
    margin-bottom: 24px;
    box-shadow: 0 4px 12px rgba(37, 99, 235, 0.2);
}

.step h3 {
    font-size: 22px;
    font-weight: 700;
    margin-bottom: 16px;
    color: var(--text);
    letter-spacing: -0.01em;
}

.step p {
    color: var(--text-secondary);
    line-height: 1.6;
    font-size: 16px;
    font-weight: 400;
}

.step-arrow {
    font-size: 0;
    color: var(--border);
    font-weight: 300;
    align-self: center;
    position: relative;
}

.step-arrow::after {
    content: '→';
    font-size: 32px;
    opacity: 0.3;
}

/* Pricing Section */
.pricing {
    background: var(--bg);
    position: relative;
}

.pricing-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
    gap: 32px;
    margin-bottom: 48px;
}

.pricing-card {
    background: var(--bg);
    border-radius: var(--radius-lg);
    padding: 48px 40px;
    border: 1px solid var(--border);
    position: relative;
    transition: var(--transition);
    display: flex;
    flex-direction: column;
}

.pricing-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-xl);
}

.pricing-card.featured {
    border: 2px solid var(--primary);
    box-shadow: var(--shadow-lg);
}

.popular-badge {
    position: absolute;
    top: -12px;
    left: 50%;
    transform: translateX(-50%);
    background: linear-gradient(135deg, var(--primary) 0%, var(--accent) 100%);
    color: white;
    padding: 8px 20px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: 600;
    letter-spacing: 0.05em;
    text-transform: uppercase;
    box-shadow: 0 4px 12px rgba(37, 99, 235, 0.3);
}

.pricing-header {
    text-align: center;
    margin-bottom: 40px;
}

.pricing-header h3 {
    font-size: 28px;
    font-weight: 700;
    color: var(--text);
    margin-bottom: 20px;
    letter-spacing: -0.01em;
}

.pricing-price {
    display: flex;
    align-items: baseline;
    justify-content: center;
    gap: 8px;
}

.price-amount {
    font-size: 56px;
    font-weight: 800;
    color: var(--text);
    letter-spacing: -0.03em;
}

.price-period {
    font-size: 18px;
    color: var(--text-secondary);
    font-weight: 500;
}

.pricing-features {
    list-style: none;
    margin-bottom: 40px;
    flex-grow: 1;
}

.pricing-features li {
    padding: 14px 0;
    color: var(--text-secondary);
    border-bottom: 1px solid var(--border-light);
    font-size: 16px;
    line-height: 1.5;
    font-weight: 400;
    display: flex;
    align-items: center;
    gap: 12px;
}

.pricing-features li:last-child {
    border-bottom: none;
}

.pricing-features li::before {
    content: '✓';
    color: var(--primary);
    font-weight: 700;
}

.annual-hint {
    text-align: center;
    margin-top: 24px;
    font-size: 14px;
    color: var(--text-secondary);
    font-weight: 500;
    padding: 12px;
    background: var(--bg-alt);
    border-radius: var(--radius-sm);
}

.pricing-note {
    text-align: center;
    color: var(--text-secondary);
    font-size: 15px;
    font-weight: 400;
    display: flex;
    flex-direction: column;
    gap: 12px;
    align-items: center;
}

.pricing-note p {
    display: flex;
    align-items: center;
    gap: 8px;
}

/* FAQ Section */
.faq {
    background: var(--bg-gradient);
    position: relative;
}

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

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

.faq-item:hover {
    border-color: var(--primary-light);
    box-shadow: var(--shadow-md);
}

.faq-question {
    padding: 28px 32px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    cursor: pointer;
    transition: var(--transition);
    background: var(--bg);
}

.faq-question:hover {
    background: var(--bg-alt);
}

.faq-question h3 {
    font-size: 18px;
    font-weight: 600;
    color: var(--text);
    letter-spacing: -0.01em;
    margin-right: 24px;
}

.faq-toggle {
    font-size: 24px;
    font-weight: 300;
    color: var(--primary);
    transition: var(--transition);
    flex-shrink: 0;
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    background: var(--primary-glow);
}

.faq-item.active .faq-toggle {
    transform: rotate(45deg);
    background: var(--primary);
    color: white;
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.5s cubic-bezier(0.4, 0, 0.2, 1);
}

.faq-item.active .faq-answer {
    max-height: 500px;
}

.faq-answer p {
    padding: 0 32px 32px;
    color: var(--text-secondary);
    line-height: 1.7;
    font-size: 16px;
    font-weight: 400;
}

/* CTA Section */
.cta {
    background: linear-gradient(135deg, var(--primary) 0%, var(--accent) 100%);
    color: white;
    text-align: center;
    padding: 100px 0;
    position: relative;
    overflow: hidden;
}

.cta::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: radial-gradient(circle at 50% 50%, rgba(255, 255, 255, 0.1) 0%, transparent 50%);
}

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

.cta .btn-primary {
    background: white !important;
    color: var(--primary) !important;
    font-weight: 700;
}

.cta .btn-primary:hover {
    transform: translateY(-4px);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.2);
}

.cta h2 {
    font-size: 48px;
    font-weight: 800;
    margin-bottom: 24px;
    letter-spacing: -0.02em;
}

.cta p {
    font-size: 20px;
    margin-bottom: 48px;
    opacity: 0.95;
    font-weight: 400;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

/* Footer */
.footer {
    background: var(--bg);
    color: var(--text-secondary);
    padding: 80px 0 40px;
    border-top: 1px solid var(--border);
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 64px;
    margin-bottom: 64px;
}

.footer-section h3 {
    font-size: 20px;
    font-weight: 700;
    margin-bottom: 24px;
    background: linear-gradient(135deg, var(--primary) 0%, var(--accent) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.footer-section h4 {
    font-size: 16px;
    font-weight: 600;
    margin-bottom: 20px;
    color: var(--text);
    letter-spacing: 0.01em;
}

.footer-section p {
    color: var(--text-secondary);
    font-size: 15px;
    font-weight: 400;
    line-height: 1.6;
}

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

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

.footer-section a {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 15px;
    font-weight: 400;
    transition: var(--transition);
    display: inline-block;
    padding: 4px 0;
}

.footer-section a:hover {
    color: var(--primary);
    transform: translateX(4px);
}

.footer-bottom {
    text-align: center;
    padding-top: 40px;
    border-top: 1px solid var(--border);
    color: var(--text-secondary);
    font-size: 14px;
    font-weight: 400;
}

/* Responsive Design */
@media (max-width: 1024px) {
    .hero-title {
        font-size: 56px;
    }
    
    .section-title {
        font-size: 40px;
    }
    
    .steps {
        flex-direction: column;
        gap: 32px;
    }
    
    .step-arrow::after {
        content: '↓';
        font-size: 40px;
        display: block;
        transform: rotate(0deg);
        margin: 20px 0;
    }
}

@media (max-width: 768px) {
    .container {
        padding: 0 24px;
    }
    
    .nav-links a:not(.btn) {
        display: none;
    }
    
    .nav-links .btn {
        padding: 10px 20px;
        font-size: 13px;
    }

    .hero {
        padding: 140px 0 80px;
    }
    
    .hero-title {
        font-size: 42px;
    }
    
    .hero-subtitle {
        font-size: 18px;
    }
    
    .hero-buttons {
        flex-direction: column;
        align-items: center;
    }
    
    .btn-large {
        width: 100%;
        max-width: 280px;
    }
    
    .hero-stats {
        gap: 40px;
    }
    
    .stat-number {
        font-size: 32px;
    }
    
    .section-title {
        font-size: 36px;
    }
    
    .pricing-grid,
    .features-grid {
        grid-template-columns: 1fr;
    }
    
    .feature-card,
    .pricing-card,
    .step {
        padding: 32px 24px;
    }
    
    .cta h2 {
        font-size: 36px;
    }
}

@media (max-width: 480px) {
    .hero-title {
        font-size: 36px;
    }
    
    .section-title {
        font-size: 32px;
    }
    
    .section-subtitle {
        font-size: 16px;
    }
    
    .hero-stats {
        gap: 32px;
        flex-direction: column;
    }
    
    .faq-question {
        padding: 20px 24px;
    }
    
    .faq-answer p {
        padding: 0 24px 24px;
    }
    
    .footer-content {
        grid-template-columns: 1fr;
        gap: 40px;
    }
}

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

.fade-in-up {
    animation: fadeInUp 0.8s ease forwards;
}

/* 浮动动画 */
@keyframes float {
    0%, 100% {
        transform: translateY(0);
    }
    50% {
        transform: translateY(-10px);
    }
}

.floating {
    animation: float 3s ease-in-out infinite;
}