* { margin: 0; padding: 0; box-sizing: border-box; }
:root {
    --primary: #2563eb;
    --primary-dark: #1d4ed8;
    --primary-light: #dbeafe;
    --secondary: #64748b;
    --success: #22c55e;
    --bg: #f8fafc;
    --card: #ffffff;
    --text: #1e293b;
    --text-light: #64748b;
    --border: #e2e8f0;
    --shadow: 0 4px 20px rgba(0,0,0,0.08);
    --shadow-hover: 0 8px 30px rgba(0,0,0,0.12);
}
body { font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', sans-serif; background-color: var(--bg); color: var(--text); line-height: 1.6; overflow-x: hidden; }

nav { background: rgba(255,255,255,0.95); backdrop-filter: blur(10px); color: var(--text); padding: 1rem 5%; position: fixed; width: 100%; top: 0; z-index: 100; box-shadow: 0 2px 10px rgba(0,0,0,0.05); transition: all 0.3s; }
nav.scrolled { background: rgba(255,255,255,0.98); box-shadow: 0 4px 20px rgba(0,0,0,0.1); }
.nav-container { max-width: 1200px; margin: 0 auto; display: flex; justify-content: space-between; align-items: center; }
.logo { font-size: 1.5rem; font-weight: 700; display: flex; align-items: center; gap: 0.7rem; }
.logo-icon { width: 36px; height: 36px; background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%); border-radius: 10px; display: flex; align-items: center; justify-content: center; color: white; font-size: 1.1rem; font-weight: 800; }
nav ul { display: flex; list-style: none; gap: 2.5rem; }
nav a { color: var(--text-light); text-decoration: none; font-weight: 500; font-size: 0.95rem; transition: all 0.3s; position: relative; }
nav a:hover { color: var(--primary); }
nav a::after { content: ''; position: absolute; bottom: -4px; left: 0; width: 0; height: 2px; background: var(--primary); transition: width 0.3s; }
nav a:hover::after { width: 100%; }
.nav-btn { background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%); color: white; padding: 0.6rem 1.5rem; border-radius: 8px; }
.nav-btn:hover { color: white !important; box-shadow: 0 4px 15px rgba(37,99,235,0.4); }

.hero { margin-top: 72px; background: linear-gradient(135deg, #eff6ff 0%, #e0f2fe 50%, #f0f9ff 100%); padding: 6rem 5% 5rem; position: relative; overflow: hidden; }
.hero::before { content: ''; position: absolute; top: -100px; right: -100px; width: 500px; height: 500px; background: radial-gradient(circle, rgba(37,99,235,0.1) 0%, transparent 70%); border-radius: 50%; }
.hero::after { content: ''; position: absolute; bottom: -50px; left: -50px; width: 300px; height: 300px; background: radial-gradient(circle, rgba(37,99,235,0.08) 0%, transparent 70%); border-radius: 50%; }
.hero-container { max-width: 1200px; margin: 0 auto; display: grid; grid-template-columns: 1fr 1fr; gap: 5rem; align-items: center; position: relative; z-index: 1; }
.hero-text h1 { font-size: 3rem; color: #0f172a; margin-bottom: 1.2rem; line-height: 1.25; font-weight: 800; }
.hero-text h1 span { background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%); -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text; }
.hero-text p { font-size: 1.15rem; color: var(--text-light); margin-bottom: 2.5rem; max-width: 500px; }
.cta-group { display: flex; gap: 1.5rem; }
.cta-btn { display: inline-block; background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%); color: white; padding: 1rem 2.2rem; border-radius: 10px; text-decoration: none; font-weight: 600; font-size: 1rem; transition: all 0.3s; box-shadow: 0 6px 20px rgba(37,99,235,0.4); }
.cta-btn:hover { transform: translateY(-3px); box-shadow: 0 10px 30px rgba(37,99,235,0.5); }
.cta-btn-outline { background: transparent; border: 2px solid var(--primary); color: var(--primary); box-shadow: none; }
.cta-btn-outline:hover { background: var(--primary); color: white; }
.hero-image { background: white; border-radius: 24px; padding: 2.5rem; box-shadow: var(--shadow); }
.dashboard-preview { display: grid; grid-template-columns: repeat(2, 1fr); gap: 1.2rem; }
.stat-card { background: linear-gradient(135deg, #eff6ff 0%, #dbeafe 100%); padding: 1.5rem; border-radius: 16px; text-align: center; border: 1px solid #bfdbfe; transition: all 0.3s; }
.stat-card:hover { transform: translateY(-4px); box-shadow: 0 8px 25px rgba(37,99,235,0.2); }
.stat-card .number { font-size: 2.2rem; font-weight: 800; color: var(--primary-dark); margin-bottom: 0.3rem; }
.stat-card .label { font-size: 0.85rem; color: var(--text-light); font-weight: 500; }

.features { padding: 1.5rem 5% 0.5rem; max-width: 1200px; margin: 0 auto; }
.section-title { text-align: center; margin-bottom: 2rem; }
.section-title h2 { font-size: 2.2rem; color: #0f172a; margin-bottom: 0.8rem; font-weight: 700; }
.section-title p { color: var(--text-light); font-size: 1.05rem; max-width: 600px; margin: 0 auto; }

.paper-analysis { background: white; border-radius: 24px; padding: 3rem; box-shadow: var(--shadow); margin-bottom: 4rem; }
.analysis-header { display: flex; align-items: center; justify-content: space-between; margin-bottom: 2.5rem; }
.header-left { display: flex; align-items: center; gap: 2rem; }
.feature-icon { width: 68px; height: 68px; background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%); border-radius: 18px; display: flex; align-items: center; justify-content: center; font-size: 1.6rem; color: white; box-shadow: 0 8px 25px rgba(37,99,235,0.3); }
.feature-title h3 { font-size: 1.6rem; color: #0f172a; margin-bottom: 0.3rem; font-weight: 700; }
.feature-title p { color: var(--text-light); font-size: 1rem; }
.download-btn { display: inline-flex; align-items: center; padding: 0.7rem 1.5rem; background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%); color: white; border-radius: 12px; font-size: 0.95rem; font-weight: 500; text-decoration: none; box-shadow: 0 4px 15px rgba(37,99,235,0.3); transition: all 0.3s; white-space: nowrap; }
.download-btn:hover { transform: translateY(-2px); box-shadow: 0 6px 20px rgba(37,99,235,0.4); }
.analysis-content { display: grid; grid-template-columns: repeat(2, 1fr); gap: 1.5rem; margin-bottom: 2.5rem; }
.dimension-card { background: linear-gradient(180deg, #f8fafc 0%, #f1f5f9 100%); border-radius: 18px; padding: 2rem; text-align: center; transition: all 0.3s; border: 1px solid var(--border); }
.dimension-card:hover { transform: translateY(-6px); box-shadow: var(--shadow-hover); border-color: var(--primary-light); }
.dimension-icon { width: 56px; height: 56px; background: linear-gradient(135deg, #dbeafe 0%, #bfdbfe 100%); border-radius: 14px; display: flex; align-items: center; justify-content: center; margin: 0 auto 1.2rem; font-size: 1.3rem; color: var(--primary); }
.dimension-card h4 { color: #0f172a; margin-bottom: 0.6rem; font-size: 1.15rem; font-weight: 600; }
.dimension-card p { color: var(--text-light); font-size: 0.9rem; line-height: 1.6; }
.highlight-red { color: #dc2626; font-weight: 700; }
.data-preview { background: #f8fafc; border-radius: 16px; padding: 2rem; border: 1px solid var(--border); }
.data-preview h5 { color: #334155; margin-bottom: 1.2rem; font-size: 1rem; font-weight: 600; }
.mini-chart { display: flex; align-items: flex-end; gap: 0.6rem; height: 90px; padding: 0 0.5rem; }
.chart-bar { flex: 1; background: linear-gradient(180deg, var(--primary) 0%, var(--primary-dark) 100%); border-radius: 6px 6px 0 0; position: relative; transition: all 0.3s; cursor: pointer; }
.chart-bar:nth-child(odd) { background: linear-gradient(180deg, #60a5fa 0%, var(--primary) 100%); }
.chart-bar:hover { opacity: 0.8; }
.chart-bar:hover::after { content: attr(data-value) '%'; position: absolute; top: -30px; left: 50%; transform: translateX(-50%); background: #1e293b; color: white; padding: 4px 10px; border-radius: 6px; font-size: 0.75rem; font-weight: 500; white-space: nowrap; }
.analysis-footer { margin-top: 2rem; display: flex; justify-content: space-between; align-items: center; background: linear-gradient(135deg, #eff6ff 0%, #dbeafe 50%, #f0f9ff 100%); border-radius: 16px; padding: 1.8rem 2.2rem; border: 1px solid #bfdbfe; position: relative; overflow: hidden; }
.analysis-footer::before { content: ''; position: absolute; top: 0; left: 0; width: 4px; height: 100%; background: linear-gradient(180deg, var(--primary) 0%, var(--primary-dark) 100%); }
.footer-left { display: flex; align-items: center; gap: 1.3rem; }
.footer-icon { width: 48px; height: 48px; background: rgba(37,99,235,0.1); border-radius: 12px; display: flex; align-items: center; justify-content: center; font-size: 1.1rem; color: var(--primary); font-weight: 600; }
.footer-text h5 { font-size: 1.1rem; color: #0f172a; margin-bottom: 0.25rem; font-weight: 600; }
.footer-text p { font-size: 0.85rem; color: var(--text-light); }
.footer-right { flex-shrink: 0; }
.analysis-link { display: inline-block; background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%); color: white; padding: 0.85rem 1.8rem; border-radius: 10px; text-decoration: none; font-weight: 600; font-size: 0.9rem; transition: all 0.3s; box-shadow: 0 4px 15px rgba(37,99,235,0.3); }
.analysis-link:hover { transform: translateY(-3px); box-shadow: 0 8px 25px rgba(37,99,235,0.4); }

.ai-features { display: grid; grid-template-columns: repeat(3, 1fr); gap: 2.2rem; }
.ai-card { background: white; border-radius: 24px; padding: 2.5rem; box-shadow: var(--shadow); text-align: center; transition: all 0.3s; }
.ai-card:hover { transform: translateY(-10px); box-shadow: var(--shadow-hover); }
.ai-icon { width: 80px; height: 80px; border-radius: 22px; display: flex; align-items: center; justify-content: center; margin: 0 auto 1.8rem; font-size: 2rem; }
.ai-icon.blue { background: linear-gradient(135deg, #dbeafe 0%, #bfdbfe 100%); color: var(--primary); }
.ai-icon.green { background: linear-gradient(135deg, #d1fae5 0%, #a7f3d0 100%); color: #059669; }
.ai-icon.purple { background: linear-gradient(135deg, #ede9fe 0%, #ddd6fe 100%); color: #7c3aed; }
.ai-card h3 { font-size: 1.35rem; color: #0f172a; margin-bottom: 1rem; font-weight: 700; }
.ai-card p { color: var(--text-light); font-size: 0.95rem; margin-bottom: 1rem; line-height: 1.5; }
.feature-list { text-align: left; padding-left: 0.5rem; }
.feature-list li { list-style: none; padding: 0.25rem 0; padding-left: 1.8rem; position: relative; color: #475569; font-size: 0.85rem; line-height: 1.4; }
.feature-list li::before { content: ''; position: absolute; left: 0; top: 0.65rem; width: 8px; height: 8px; background: var(--success); border-radius: 50%; }
.ai-card-link { display: inline-block; margin-top: 1rem; padding: 0.7rem 1.6rem; background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%); color: white; border-radius: 10px; text-decoration: none; font-weight: 600; font-size: 0.9rem; transition: all 0.3s; box-shadow: 0 4px 15px rgba(37,99,235,0.3); }
.ai-card-link:hover { transform: translateY(-3px); box-shadow: 0 8px 25px rgba(37,99,235,0.4); }

.workflow { padding: 5rem 5%; background: linear-gradient(180deg, #f8fafc 0%, #f1f5f9 100%); }
.workflow-container { max-width: 1200px; margin: 0 auto; }
.workflow-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 2rem; }
.workflow-item { text-align: center; position: relative; }
.workflow-item::after { content: '→'; position: absolute; top: 30px; right: -1rem; color: var(--border); font-size: 1.5rem; }
.workflow-item:last-child::after { display: none; }
.workflow-icon { width: 70px; height: 70px; background: white; border-radius: 20px; display: flex; align-items: center; justify-content: center; margin: 0 auto 1.5rem; font-size: 1.8rem; box-shadow: var(--shadow); transition: all 0.3s; }
.workflow-item:hover .workflow-icon { transform: scale(1.1); box-shadow: var(--shadow-hover); }
.workflow-item h4 { font-size: 1.1rem; color: #0f172a; margin-bottom: 0.5rem; font-weight: 600; }
.workflow-item p { font-size: 0.85rem; color: var(--text-light); line-height: 1.5; }

.partners { padding: 5rem 5%; max-width: 1200px; margin: 0 auto; }
.partners-title { text-align: center; margin-bottom: 3rem; }
.partners-title h3 { font-size: 1.5rem; color: var(--text-light); font-weight: 500; }
.partners-grid { display: grid; grid-template-columns: repeat(5, 1fr); gap: 2rem; }
.partner-item { background: #f8fafc; border-radius: 16px; padding: 1.5rem; display: flex; align-items: center; justify-content: center; transition: all 0.3s; }
.partner-item:hover { background: white; box-shadow: var(--shadow); }
.partner-item span { font-size: 1rem; color: var(--text-light); font-weight: 500; }

.advantages { background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%); padding: 3rem 5%; margin-top: 0.5rem; }
.advantages-container { max-width: 1200px; margin: 0 auto; }
.advantages-title { text-align: center; margin-bottom: 4rem; color: white; }
.advantages-title h2 { font-size: 2rem; margin-bottom: 0.8rem; font-weight: 700; }
.advantages-title p { opacity: 0.9; }
.advantages-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 2rem; }
.advantage-item { background: rgba(255,255,255,0.1); backdrop-filter: blur(10px); border-radius: 20px; padding: 2rem; text-align: center; color: white; transition: all 0.3s; }
.advantage-item:hover { background: rgba(255,255,255,0.15); transform: translateY(-5px); }
.advantage-item .icon { font-size: 2rem; margin-bottom: 1rem; }
.advantage-item h4 { font-size: 1.1rem; margin-bottom: 0.5rem; font-weight: 600; }
.advantage-item p { font-size: 0.85rem; opacity: 0.85; line-height: 1.5; }

.testimonials { padding: 5rem 5%; max-width: 1200px; margin: 0 auto; }
.testimonials-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 2rem; }
.testimonial-card { background: white; border-radius: 20px; padding: 2rem; box-shadow: var(--shadow); transition: all 0.3s; }
.testimonial-card:hover { transform: translateY(-5px); box-shadow: var(--shadow-hover); }
.testimonial-content { color: var(--text-light); font-size: 0.95rem; line-height: 1.7; margin-bottom: 1.5rem; }
.testimonial-author { display: flex; align-items: center; gap: 1rem; }
.author-avatar { width: 40px; height: 40px; background: linear-gradient(135deg, var(--primary-light) 0%, #bfdbfe 100%); border-radius: 50%; display: flex; align-items: center; justify-content: center; color: var(--primary); font-weight: 600; }
.author-info h5 { font-size: 0.95rem; color: #0f172a; font-weight: 600; }
.author-info p { font-size: 0.8rem; color: var(--text-light); }

.cta-section { padding: 2rem 5%; background: linear-gradient(135deg, #0f172a 0%, #1e293b 100%); }
.cta-container { max-width: 800px; margin: 0 auto; text-align: center; color: white; }
.cta-container h2 { font-size: 2.2rem; margin-bottom: 1rem; font-weight: 700; }
.cta-container p { font-size: 1.1rem; opacity: 0.85; margin-bottom: 2.5rem; }
.cta-group { justify-content: center; }

footer { background: #0f172a; color: white; padding: 4rem 5% 2rem; }
.footer-container { max-width: 1200px; margin: 0 auto; display: grid; grid-template-columns: repeat(4, 1fr); gap: 2.5rem; }
.footer-brand { grid-column: span 1; }
.footer-brand .logo { margin-bottom: 1rem; }
.footer-brand p { color: rgba(255,255,255,0.6); font-size: 0.9rem; line-height: 1.6; }
.footer-section h4 { margin-bottom: 1.2rem; color: white; font-weight: 600; font-size: 1rem; }
.footer-section ul { list-style: none; }
.footer-section li { padding: 0.4rem 0; }
.footer-section a { color: rgba(255,255,255,0.6); text-decoration: none; font-size: 0.9rem; transition: color 0.3s; }
.footer-section a:hover { color: white; }
.footer-bottom { text-align: center; margin-top: 3rem; padding-top: 2rem; border-top: 1px solid rgba(255,255,255,0.1); color: rgba(255,255,255,0.4); font-size: 0.85rem; }

.help-link { display: flex; justify-content: space-between; align-items: center; background: linear-gradient(135deg, #eff6ff 0%, #dbeafe 50%, #f0f9ff 100%); border-radius: 16px; padding: 1.8rem 2.2rem; border: 1px solid #bfdbfe; position: relative; overflow: hidden; max-width: 1200px; margin: 2rem auto 0; transition: all 0.3s; }
.help-link::before { content: ''; position: absolute; top: 0; left: 0; width: 4px; height: 100%; background: linear-gradient(180deg, var(--primary) 0%, var(--primary-dark) 100%); }
.help-link .help-left { display: flex; align-items: center; gap: 1.3rem; }
.help-link .help-icon { width: 48px; height: 48px; background: rgba(37,99,235,0.1); border-radius: 12px; display: flex; align-items: center; justify-content: center; font-size: 1.1rem; color: var(--primary); font-weight: 600; }
.help-link .help-text h5 { font-size: 1.1rem; color: #0f172a; margin-bottom: 0.25rem; font-weight: 600; }
.help-link .help-text p { font-size: 0.85rem; color: var(--text-light); }
.help-link .help-right { flex-shrink: 0; }
.help-link .help-right-link { display: inline-block; background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%); color: white; padding: 0.85rem 1.8rem; border-radius: 10px; font-weight: 600; font-size: 0.9rem; transition: all 0.3s; box-shadow: 0 4px 15px rgba(37,99,235,0.3); }
.help-link:hover { transform: translateY(-3px); box-shadow: 0 8px 25px rgba(37,99,235,0.15); }
.help-link:hover .help-right-link { transform: translateY(-3px); box-shadow: 0 8px 25px rgba(37,99,235,0.4); }

.modal-overlay { display: none; position: fixed; top: 0; left: 0; width: 100%; height: 100%; background: rgba(0,0,0,0.6); backdrop-filter: blur(4px); z-index: 1000; justify-content: center; align-items: center; }
.modal-overlay.active { display: flex; }
.modal { background: white; border-radius: 20px; padding: 2.5rem; max-width: 400px; width: 90%; box-shadow: 0 20px 60px rgba(0,0,0,0.3); transform: scale(0.9); opacity: 0; transition: all 0.3s; }
.modal-overlay.active .modal { transform: scale(1); opacity: 1; }
.modal-header { text-align: center; margin-bottom: 1.5rem; }
.modal-header h3 { font-size: 1.5rem; color: #0f172a; margin-bottom: 0.5rem; }
.modal-header p { color: var(--text-light); font-size: 0.95rem; }
.modal-content { margin-bottom: 2rem; }
.contact-item { display: flex; align-items: center; gap: 1rem; padding: 1rem 0; border-bottom: 1px solid var(--border); }
.contact-item:last-child { border-bottom: none; }
.contact-icon { width: 44px; height: 44px; background: var(--primary-light); border-radius: 12px; display: flex; align-items: center; justify-content: center; color: var(--primary); font-size: 1.2rem; }
.contact-info h4 { font-size: 1rem; color: #0f172a; margin-bottom: 0.25rem; }
.contact-info p { font-size: 0.9rem; color: var(--text-light); }
.modal-close { width: 100%; padding: 0.9rem; background: var(--primary); color: white; border: none; border-radius: 10px; font-size: 1rem; font-weight: 600; cursor: pointer; transition: all 0.3s; }
.modal-close:hover { background: var(--primary-dark); transform: translateY(-2px); }

@media (max-width: 900px) {
    .hero-container, .ai-features, .advantages-grid, .footer-container, .workflow-grid, .partners-grid, .testimonials-grid { grid-template-columns: 1fr; }
    .analysis-content { grid-template-columns: 1fr; }
    .analysis-footer { flex-direction: column; gap: 1.2rem; text-align: center; }
    .footer-left { flex-direction: column; }
    .help-link { flex-direction: column; gap: 1.2rem; text-align: center; }
    .help-left { flex-direction: column; }
    .hero-text h1 { font-size: 2rem; }
    .hero-container { gap: 3rem; }
    nav ul { gap: 1.5rem; font-size: 0.85rem; }
    .advantages-grid { gap: 1.5rem; }
    .workflow-item::after { display: none; }
    .partner-item { padding: 1rem; }
    .partner-item span { font-size: 0.9rem; }
}

@media (max-width: 480px) {
    .hero { padding: 4rem 3% 3rem; }
    .features { padding: 1.5rem 3% 0.5rem; }
    .paper-analysis { padding: 1.2rem; }
    .analysis-header { gap: 1rem; margin-bottom: 1.5rem; flex-direction: column; align-items: flex-start; }
    .header-left { gap: 1.2rem; }
    .download-btn { padding: 0.5rem 1rem; font-size: 0.85rem; border-radius: 10px; align-self: center; margin-top: 0.5rem; }
    .feature-icon { width: 50px; height: 50px; font-size: 1.2rem; }
    .feature-title h3 { font-size: 1.2rem; }
    .analysis-content { gap: 1rem; margin-bottom: 1.5rem; }
    .dimension-card { padding: 1.2rem; }
    .dimension-icon { width: 44px; height: 44px; font-size: 1rem; margin-bottom: 0.8rem; }
    .dimension-card h4 { font-size: 1rem; margin-bottom: 0.4rem; }
    .dimension-card p { font-size: 0.82rem; }
    .analysis-footer { padding: 1rem 1.2rem; }
    .footer-icon { width: 40px; height: 40px; font-size: 0.9rem; }
    .footer-left { gap: 1rem; }
    .footer-text h5 { font-size: 0.95rem; }
    .footer-text p { font-size: 0.8rem; }
    .analysis-link { padding: 0.65rem 1.4rem; font-size: 0.82rem; }
    .ai-features { gap: 1.2rem; }
    .ai-card { padding: 1.4rem; }
    .ai-icon { width: 60px; height: 60px; font-size: 1.5rem; margin-bottom: 1.2rem; }
    .ai-card h3 { font-size: 1.1rem; margin-bottom: 0.8rem; }
    .ai-card p { font-size: 0.85rem; margin-bottom: 1.2rem; }
    .feature-list li { font-size: 0.82rem; padding-left: 1.5rem; padding: 0.4rem 0 0.4rem 1.5rem; }
    .ai-card-link { margin-top: 1.2rem; padding: 0.55rem 1.3rem; font-size: 0.82rem; }
    .help-link { padding: 1rem 1.2rem; flex-direction: column; gap: 1rem; }
    .help-icon { width: 40px; height: 40px; font-size: 0.9rem; }
    .help-left { gap: 0.5rem; }
    .help-text h5 { font-size: 0.95rem; }
    .help-text p { font-size: 0.8rem; }
    .help-right-link { padding: 0.65rem 1.4rem; font-size: 0.82rem; }
    .advantages { padding: 2rem 3%; }
    .advantages-title h2 { font-size: 1.5rem; }
    .advantages-grid { gap: 1rem; }
    .advantage-item { padding: 1.4rem; }
    .advantage-item h4 { font-size: 1rem; }
    .advantage-item p { font-size: 0.82rem; }
    .cta-section { padding: 1.5rem 3%; }
    .cta-container h2 { font-size: 1.5rem; }
    .cta-container p { font-size: 0.95rem; }
    .cta-btn { padding: 0.85rem 1.8rem; font-size: 0.9rem; }
    .section-title h2 { font-size: 1.5rem; }
    .section-title p { font-size: 0.9rem; }
}

/* 回顶部按钮 */
.back-to-top {
    position: fixed;
    bottom: 25px;
    right: 25px;
    width: 46px;
    height: 46px;
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    text-decoration: none;
    box-shadow: 0 4px 16px rgba(37, 99, 235, 0.5);
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px);
    transition: all 0.3s cubic-bezier(.2,.8,.2,1);
    z-index: 9999;
    cursor: pointer;
    border: none;
    font-size: 1.15rem;
    padding: 0;
}
.back-to-top.show {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}
.back-to-top:hover {
    transform: translateY(-3px);
    box-shadow: 0 6px 24px rgba(37, 99, 235, 0.65);
}
@media (max-width: 600px) {
    .back-to-top {
        bottom: 20px;
        right: 20px;
        width: 42px;
        height: 42px;
        font-size: 1rem;
    }
}