/* ===== Reset & Base ===== */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; font-size: 16px; }
body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
    color: #1E293B; background: #FFFFFF; line-height: 1.6;
}
a { text-decoration: none; color: inherit; }
img { max-width: 100%; height: auto; display: block; }
ul, ol { list-style: none; }

/* ===== Container ===== */
.container { max-width: 1200px; margin: 0 auto; padding: 0 20px; }

/* ===== Navigation ===== */
.navbar {
    position: fixed; top: 0; left: 0; right: 0; z-index: 1000;
    background: #1E293B; height: 64px;
    display: flex; align-items: center;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}
.navbar .container {
    display: flex; align-items: center; justify-content: space-between; width: 100%;
}
.nav-logo {
    font-size: 22px; font-weight: 700; color: #FFFFFF;
    display: flex; align-items: center; gap: 8px;
}
.nav-logo-icon {
    width: 32px; height: 32px; background: #2563EB; border-radius: 8px;
    display: flex; align-items: center; justify-content: center;
    color: #fff; font-weight: 700; font-size: 14px;
}
.nav-links { display: flex; align-items: center; gap: 28px; }
.nav-links a {
    color: #CBD5E1; font-size: 15px; font-weight: 500;
    transition: color 0.2s;
}
.nav-links a:hover { color: #FFFFFF; }
.nav-cta {
    background: #2563EB; color: #FFFFFF !important; padding: 8px 20px;
    border-radius: 6px; font-weight: 600; transition: background 0.2s;
}
.nav-cta:hover { background: #1D4ED8; }
.nav-toggle { display: none; flex-direction: column; gap: 5px; cursor: pointer; }
.nav-toggle span { width: 24px; height: 2px; background: #fff; border-radius: 2px; }

/* ===== Hero ===== */
.hero {
    padding: 140px 0 80px; background: linear-gradient(135deg, #1E293B 0%, #0F172A 100%);
    text-align: center; color: #FFFFFF;
}
.hero h1 { font-size: 48px; font-weight: 800; margin-bottom: 16px; line-height: 1.2; }
.hero .subtitle { font-size: 20px; color: #94A3B8; margin-bottom: 12px; max-width: 700px; margin-left: auto; margin-right: auto; }
.hero .trust-badge { font-size: 14px; color: #64748B; margin-bottom: 36px; }
.hero-buttons { display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; margin-bottom: 32px; }
.btn-primary {
    display: inline-block; background: #2563EB; color: #FFFFFF;
    padding: 14px 36px; border-radius: 8px; font-size: 18px; font-weight: 700;
    transition: background 0.2s, transform 0.2s;
}
.btn-primary:hover { background: #1D4ED8; transform: translateY(-2px); }
.btn-secondary {
    display: inline-block; background: transparent; color: #FFFFFF;
    padding: 14px 36px; border-radius: 8px; font-size: 18px; font-weight: 600;
    border: 2px solid #475569; transition: border-color 0.2s;
}
.btn-secondary:hover { border-color: #2563EB; }
.platform-icons { display: flex; gap: 24px; justify-content: center; margin-top: 24px; }
.platform-icon {
    display: flex; flex-direction: column; align-items: center; gap: 6px;
    color: #94A3B8; font-size: 13px; transition: color 0.2s;
}
.platform-icon:hover { color: #FFFFFF; }
.platform-icon .icon {
    width: 48px; height: 48px; background: rgba(255,255,255,0.1);
    border-radius: 12px; display: flex; align-items: center; justify-content: center;
    font-size: 22px; transition: background 0.2s;
}
.platform-icon:hover .icon { background: rgba(37,99,235,0.3); }
.hero-preview {
    margin-top: 48px; max-width: 800px; margin-left: auto; margin-right: auto;
    background: rgba(255,255,255,0.05); border-radius: 16px; padding: 24px;
    border: 1px solid rgba(255,255,255,0.1);
}
.hero-preview-img {
    width: 100%; height: 300px; background: linear-gradient(135deg, #1E3A5F, #2563EB);
    border-radius: 12px; display: flex; align-items: center; justify-content: center;
    color: #94A3B8; font-size: 16px;
}

/* ===== Section Common ===== */
.section { padding: 80px 0; }
.section-alt { background: #F8FAFC; }
.section-title {
    text-align: center; font-size: 36px; font-weight: 700;
    margin-bottom: 12px; color: #1E293B;
}
.section-desc {
    text-align: center; font-size: 16px; color: #64748B;
    margin-bottom: 48px; max-width: 600px; margin-left: auto; margin-right: auto;
}

/* ===== Features ===== */
.features-grid {
    display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px;
}
.feature-card {
    background: #FFFFFF; border-radius: 12px; padding: 32px 24px;
    text-align: center; border: 1px solid #E2E8F0;
    transition: transform 0.2s, box-shadow 0.2s;
}
.feature-card:hover { transform: translateY(-4px); box-shadow: 0 12px 24px rgba(0,0,0,0.08); }
.feature-icon {
    width: 64px; height: 64px; background: #EFF6FF; border-radius: 16px;
    display: flex; align-items: center; justify-content: center;
    margin: 0 auto 16px; font-size: 28px;
}
.feature-card h3 { font-size: 18px; font-weight: 700; margin-bottom: 8px; }
.feature-card p { font-size: 14px; color: #64748B; line-height: 1.6; }

/* ===== Download Section ===== */
.download-grid {
    display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px;
}
.download-card {
    background: #FFFFFF; border-radius: 12px; padding: 32px 24px;
    text-align: center; border: 1px solid #E2E8F0;
    transition: transform 0.2s, box-shadow 0.2s;
}
.download-card:hover { transform: translateY(-4px); box-shadow: 0 12px 24px rgba(0,0,0,0.08); }
.download-card .platform-logo {
    width: 56px; height: 56px; margin: 0 auto 16px;
    background: #F1F5F9; border-radius: 14px;
    display: flex; align-items: center; justify-content: center; font-size: 26px;
}
.download-card h3 { font-size: 18px; font-weight: 700; margin-bottom: 6px; }
.download-card .version { font-size: 13px; color: #94A3B8; margin-bottom: 16px; }
.download-card .btn-download {
    display: inline-block; background: #2563EB; color: #FFFFFF;
    padding: 10px 28px; border-radius: 6px; font-size: 15px; font-weight: 600;
    transition: background 0.2s;
}
.download-card .btn-download:hover { background: #1D4ED8; }

/* ===== Testimonials ===== */
.testimonials-grid {
    display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px;
}
.testimonial-card {
    background: #FFFFFF; border-radius: 12px; padding: 28px;
    border: 1px solid #E2E8F0;
}
.testimonial-stars { color: #F59E0B; font-size: 16px; margin-bottom: 12px; }
.testimonial-text { font-size: 14px; color: #475569; line-height: 1.7; margin-bottom: 16px; }
.testimonial-author { display: flex; align-items: center; gap: 12px; }
.testimonial-avatar {
    width: 40px; height: 40px; background: #E2E8F0; border-radius: 50%;
    display: flex; align-items: center; justify-content: center;
    font-size: 16px; font-weight: 700; color: #64748B;
}
.testimonial-info .name { font-size: 14px; font-weight: 600; }
.testimonial-info .source { font-size: 12px; color: #94A3B8; }
.trust-badges {
    display: flex; gap: 32px; justify-content: center; margin-top: 40px;
    flex-wrap: wrap;
}
.trust-badge-item {
    display: flex; align-items: center; gap: 8px;
    color: #64748B; font-size: 14px;
}
.trust-badge-item .badge-icon {
    width: 36px; height: 36px; background: #F0FDF4; border-radius: 50%;
    display: flex; align-items: center; justify-content: center; font-size: 18px;
}

/* ===== Updates / Changelog ===== */
.updates-list { max-width: 800px; margin: 0 auto; }
.update-item {
    display: flex; gap: 20px; padding: 24px 0;
    border-bottom: 1px solid #E2E8F0;
}
.update-item:last-child { border-bottom: none; }
.update-date {
    min-width: 100px; font-size: 14px; color: #94A3B8; font-weight: 500;
    padding-top: 2px;
}
.update-content h3 { font-size: 16px; font-weight: 700; margin-bottom: 6px; }
.update-content p { font-size: 14px; color: #64748B; line-height: 1.6; }
.update-tag {
    display: inline-block; background: #EFF6FF; color: #2563EB;
    padding: 2px 10px; border-radius: 4px; font-size: 12px; font-weight: 600;
    margin-bottom: 6px;
}

/* ===== FAQ ===== */
.faq-list { max-width: 800px; margin: 0 auto; }
.faq-item {
    background: #FFFFFF; border-radius: 12px; padding: 28px;
    margin-bottom: 20px; border: 1px solid #E2E8F0;
}
.faq-item h3 {
    font-size: 17px; font-weight: 700; margin-bottom: 14px;
    color: #1E293B; display: flex; align-items: flex-start; gap: 10px;
}
.faq-item h3 .faq-badge {
    display: inline-block; background: #2563EB; color: #FFFFFF;
    min-width: 24px; height: 24px; border-radius: 6px;
    display: flex; align-items: center; justify-content: center;
    font-size: 13px; font-weight: 700; flex-shrink: 0;
}
.faq-steps { padding-left: 34px; }
.faq-steps li {
    font-size: 14px; color: #475569; line-height: 1.8;
    margin-bottom: 6px; list-style: decimal; padding-left: 4px;
}

/* ===== Page Header (for inner pages) ===== */
.page-header {
    padding: 120px 0 48px; background: linear-gradient(135deg, #1E293B 0%, #0F172A 100%);
    text-align: center; color: #FFFFFF;
}
.page-header h1 { font-size: 36px; font-weight: 700; margin-bottom: 12px; }
.page-header p { font-size: 16px; color: #94A3B8; max-width: 600px; margin: 0 auto; }
.breadcrumb {
    display: flex; gap: 8px; justify-content: center; margin-bottom: 16px;
    font-size: 14px; color: #64748B;
}
.breadcrumb a { color: #94A3B8; }
.breadcrumb a:hover { color: #FFFFFF; }

/* ===== Product Page ===== */
.product-features { max-width: 900px; margin: 0 auto; }
.product-feature-item {
    display: flex; gap: 32px; align-items: center;
    padding: 40px 0; border-bottom: 1px solid #E2E8F0;
}
.product-feature-item:last-child { border-bottom: none; }
.product-feature-item.reverse { flex-direction: row-reverse; }
.product-feature-text { flex: 1; }
.product-feature-text h3 { font-size: 22px; font-weight: 700; margin-bottom: 10px; }
.product-feature-text p { font-size: 15px; color: #64748B; line-height: 1.7; }
.product-feature-visual {
    flex: 0 0 300px; height: 200px; background: #F1F5F9;
    border-radius: 12px; display: flex; align-items: center;
    justify-content: center; font-size: 48px;
}

/* ===== Help Page ===== */
.help-categories {
    display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px;
    margin-bottom: 48px;
}
.help-category-card {
    background: #FFFFFF; border-radius: 12px; padding: 28px;
    border: 1px solid #E2E8F0; text-align: center;
    transition: transform 0.2s, box-shadow 0.2s;
}
.help-category-card:hover { transform: translateY(-4px); box-shadow: 0 12px 24px rgba(0,0,0,0.08); }
.help-category-icon {
    width: 56px; height: 56px; background: #EFF6FF; border-radius: 14px;
    display: flex; align-items: center; justify-content: center;
    margin: 0 auto 14px; font-size: 26px;
}
.help-category-card h3 { font-size: 16px; font-weight: 700; margin-bottom: 6px; }
.help-category-card p { font-size: 13px; color: #64748B; }

/* ===== About Page ===== */
.about-content { max-width: 800px; margin: 0 auto; }
.about-content p { font-size: 15px; color: #475569; line-height: 1.8; margin-bottom: 20px; }
.about-stats {
    display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px;
    margin: 40px 0;
}
.about-stat {
    text-align: center; padding: 24px;
    background: #FFFFFF; border-radius: 12px; border: 1px solid #E2E8F0;
}
.about-stat .stat-number { font-size: 36px; font-weight: 800; color: #2563EB; }
.about-stat .stat-label { font-size: 14px; color: #64748B; margin-top: 4px; }
.about-contact {
    background: #F8FAFC; border-radius: 12px; padding: 32px;
    margin-top: 40px;
}
.about-contact h3 { font-size: 20px; font-weight: 700; margin-bottom: 16px; }
.contact-list li {
    font-size: 15px; color: #475569; padding: 8px 0;
    display: flex; align-items: center; gap: 10px;
}

/* ===== Legal Pages ===== */
.legal-content { max-width: 800px; margin: 0 auto; }
.legal-content h2 { font-size: 22px; font-weight: 700; margin: 32px 0 12px; color: #1E293B; }
.legal-content h2:first-child { margin-top: 0; }
.legal-content p { font-size: 15px; color: #475569; line-height: 1.8; margin-bottom: 14px; }
.legal-content ul { padding-left: 20px; margin-bottom: 14px; }
.legal-content ul li {
    font-size: 15px; color: #475569; line-height: 1.8;
    margin-bottom: 6px; list-style: disc;
}

/* ===== Footer ===== */
.footer {
    background: #0F172A; color: #94A3B8; padding: 48px 0 24px;
}
.footer-grid {
    display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 40px;
    margin-bottom: 32px;
}
.footer-brand .footer-logo {
    font-size: 20px; font-weight: 700; color: #FFFFFF; margin-bottom: 12px;
    display: flex; align-items: center; gap: 8px;
}
.footer-brand p { font-size: 14px; line-height: 1.7; }
.footer-col h4 { font-size: 15px; font-weight: 600; color: #FFFFFF; margin-bottom: 14px; }
.footer-col a {
    display: block; font-size: 14px; color: #94A3B8;
    padding: 4px 0; transition: color 0.2s;
}
.footer-col a:hover { color: #FFFFFF; }
.footer-bottom {
    border-top: 1px solid #1E293B; padding-top: 20px;
    display: flex; justify-content: space-between; align-items: center;
    flex-wrap: wrap; gap: 12px;
}
.footer-bottom p { font-size: 13px; }
.footer-social { display: flex; gap: 12px; }
.footer-social a {
    width: 32px; height: 32px; background: #1E293B; border-radius: 50%;
    display: flex; align-items: center; justify-content: center;
    font-size: 14px; color: #94A3B8; transition: background 0.2s, color 0.2s;
}
.footer-social a:hover { background: #2563EB; color: #FFFFFF; }

/* ===== Responsive ===== */
@media (max-width: 1024px) {
    .features-grid, .download-grid { grid-template-columns: repeat(2, 1fr); }
    .testimonials-grid { grid-template-columns: repeat(2, 1fr); }
    .footer-grid { grid-template-columns: repeat(2, 1fr); }
    .about-stats { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 768px) {
    .nav-links { display: none; }
    .nav-toggle { display: flex; }
    .hero h1 { font-size: 32px; }
    .hero .subtitle { font-size: 16px; }
    .section-title { font-size: 28px; }
    .features-grid, .download-grid { grid-template-columns: 1fr; }
    .testimonials-grid { grid-template-columns: 1fr; }
    .help-categories { grid-template-columns: 1fr; }
    .footer-grid { grid-template-columns: 1fr; }
    .about-stats { grid-template-columns: repeat(2, 1fr); }
    .product-feature-item, .product-feature-item.reverse { flex-direction: column; }
    .product-feature-visual { flex: none; width: 100%; }
    .update-item { flex-direction: column; gap: 8px; }
    .hero-buttons { flex-direction: column; align-items: center; }
    .footer-bottom { flex-direction: column; text-align: center; }
    .page-header h1 { font-size: 28px; }
}