/* ===== Reset ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; -webkit-font-smoothing: antialiased; }
body {
    font-family: -apple-system, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Microsoft YaHei", sans-serif;
    color: #0f172a; background: #fff; line-height: 1.5; font-size: 17px;
}
img { max-width: 100%; height: auto; display: block; }
a { color: #0891b2; text-decoration: none; }
a:hover { text-decoration: underline; }
ul { list-style: none; }
.container { max-width: 1000px; margin: 0 auto; padding: 0 22px; }
.container-wide { max-width: 1400px; margin: 0 auto; padding: 0 22px; }

/* ===== Nav ===== */
.site-nav {
    position: sticky; top: 0; z-index: 100;
    background: rgba(255,255,255,0.85);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid #e2e8f0;
}
.nav-inner {
    max-width: 1040px; margin: 0 auto;
    display: flex; align-items: center; justify-content: space-between;
    height: 48px; padding: 0 22px;
}
.logo { color: #0f172a; font-size: 17px; font-weight: 700; letter-spacing: -0.01em; }
.nav-inner nav ul { display: flex; gap: 26px; }
.nav-inner nav a { color: #0f172a; font-size: 13px; opacity: 0.75; }
.nav-inner nav a:hover { opacity: 1; text-decoration: none; }

/* ===== Hero ===== */
.hero {
    background: radial-gradient(ellipse at top, #0c2a3d 0%, #06131f 60%, #030a12 100%);
    color: #fff; text-align: center; padding: 76px 22px 0; overflow: hidden;
}
.hero h1 {
    font-size: 58px; font-weight: 800; letter-spacing: -0.03em; line-height: 1.05;
    margin-bottom: 16px;
    background: linear-gradient(90deg, #67e8f9, #22d3ee, #2dd4bf);
    -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text;
}
.hero .tagline { font-size: 23px; font-weight: 600; color: #cbd5e1; margin-bottom: 16px; }
.hero .sub { font-size: 18px; color: #94a3b8; max-width: 660px; margin: 0 auto 30px; line-height: 1.7; }
.cta-group { display: flex; gap: 16px; justify-content: center; margin-bottom: 48px; flex-wrap: wrap; }
.btn {
    display: inline-block; padding: 13px 28px; border-radius: 980px;
    font-size: 16px; font-weight: 600; transition: all 0.2s;
}
.btn-primary { background: linear-gradient(135deg, #06b6d4, #0891b2); color: #fff; }
.btn-primary:hover { background: linear-gradient(135deg, #0891b2, #0e7490); text-decoration: none; }
.btn-ghost { border: 1px solid rgba(103,232,249,0.4); color: #67e8f9; }
.btn-ghost:hover { background: rgba(103,232,249,0.1); text-decoration: none; }

/* ===== Sections ===== */
.section { padding: 92px 0; }
.section-gray { background: #f6f8fa; }
.section-dark { background: #06131f; color: #fff; }
.section h2 { font-size: 42px; font-weight: 800; text-align: center; letter-spacing: -0.02em; margin-bottom: 16px; }
.section .subtitle { font-size: 19px; text-align: center; color: #64748b; max-width: 700px; margin: 0 auto 46px; line-height: 1.6; }
.section-dark .subtitle { color: #94a3b8; }

/* ===== Feature cards ===== */
.feature-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.feature-card {
    background: #fff; border: 1px solid #e2e8f0; border-radius: 20px; padding: 30px;
}
.section-dark .feature-card { background: #0d1f2d; border-color: #1e3a4d; }
.feature-card .icon {
    width: 46px; height: 46px; border-radius: 13px;
    background: linear-gradient(135deg, #06b6d4, #14b8a6);
    display: flex; align-items: center; justify-content: center;
    margin-bottom: 16px; font-size: 22px; color: #fff;
}
.feature-card h3 { font-size: 19px; font-weight: 700; margin-bottom: 8px; }
.feature-card p { font-size: 14px; color: #64748b; line-height: 1.65; }
.section-dark .feature-card p { color: #94a3b8; }

/* ===== Product cards ===== */
.product-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 22px; margin-top: 40px; }
.product-card {
    background: #fff; border: 1px solid #e2e8f0; border-radius: 22px;
    overflow: hidden; transition: all 0.25s;
}
.product-card:hover { box-shadow: 0 12px 36px rgba(6,182,212,0.15); border-color: #a5f3fc; transform: translateY(-3px); }
.product-card .card-img { width: 100%; height: 220px; object-fit: contain; background: #f6f8fa; padding: 18px; }
.product-card .card-body { padding: 24px; }
.product-card .tag {
    display: inline-block; font-size: 12px; font-weight: 700; color: #0891b2;
    background: #ecfeff; border-radius: 980px; padding: 3px 12px; margin-bottom: 10px;
}
.product-card h3 { font-size: 21px; font-weight: 700; margin-bottom: 8px; color: #0f172a; }
.product-card p { font-size: 14px; color: #64748b; line-height: 1.6; margin-bottom: 14px; }
.product-card .more { font-size: 14px; font-weight: 600; color: #0891b2; }

/* ===== FAQ cards ===== */
.faq-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
.faq-card {
    background: #fff; border: 1px solid #e2e8f0; border-radius: 16px;
    padding: 22px; transition: all 0.2s;
}
.faq-card:hover { box-shadow: 0 6px 22px rgba(6,182,212,0.12); border-color: #a5f3fc; text-decoration: none; }
.faq-card .num { font-size: 12px; font-weight: 700; color: #06b6d4; margin-bottom: 8px; letter-spacing: 0.05em; }
.faq-card h3 { font-size: 16px; font-weight: 700; color: #0f172a; margin-bottom: 6px; line-height: 1.45; }
.faq-card p { font-size: 13px; color: #64748b; line-height: 1.5; }

/* ===== Spec table ===== */
.spec-table { width: 100%; border-collapse: collapse; margin: 24px 0; font-size: 15px; }
.spec-table th, .spec-table td { padding: 14px 16px; text-align: left; border-bottom: 1px solid #e2e8f0; }
.spec-table th { background: #f6f8fa; font-weight: 700; color: #0f172a; width: 32%; }
.spec-table td { color: #334155; }

/* ===== Article ===== */
.article-page { padding: 56px 0 96px; max-width: 740px; margin: 0 auto; }
.article-page h1 { font-size: 37px; font-weight: 800; letter-spacing: -0.02em; line-height: 1.25; margin-bottom: 14px; }
.article-page .meta { font-size: 14px; color: #94a3b8; margin-bottom: 38px; padding-bottom: 20px; border-bottom: 1px solid #e2e8f0; }
.article-page h2 { font-size: 24px; font-weight: 700; margin: 38px 0 14px; }
.article-page p { font-size: 17px; line-height: 1.8; color: #1e293b; margin-bottom: 16px; }
.article-page ul { margin: 14px 0 18px; padding-left: 22px; }
.article-page ul li { font-size: 16px; line-height: 1.95; color: #334155; list-style: disc; }
.article-page strong { color: #0f172a; }
.article-hero { width: 100%; max-height: 540px; object-fit: contain; border-radius: 20px; margin-bottom: 32px; background: #f6f8fa; padding: 28px; }
.article-page .related {
    margin-top: 52px; padding: 28px;
    background: linear-gradient(135deg, #ecfeff, #f0fdfa);
    border-radius: 18px; border: 1px solid #a5f3fc;
}
.article-page .related h3 { font-size: 16px; font-weight: 700; margin-bottom: 12px; }
.article-page .related a { display: inline-block; margin: 4px 16px 4px 0; font-size: 15px; }

/* ===== 404 ===== */
.error-page {
    min-height: 70vh; display: flex; flex-direction: column;
    align-items: center; justify-content: center; text-align: center; padding: 40px 22px;
}
.error-page .code {
    font-size: 120px; font-weight: 800; line-height: 1; margin-bottom: 16px;
    background: linear-gradient(135deg, #06b6d4, #14b8a6);
    -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text;
}
.error-page h1 { font-size: 32px; font-weight: 800; margin-bottom: 12px; }
.error-page p { font-size: 17px; color: #64748b; max-width: 420px; margin-bottom: 30px; }

/* ===== Footer ===== */
.site-footer { background: #f6f8fa; border-top: 1px solid #e2e8f0; padding: 42px 0; font-size: 12px; color: #94a3b8; line-height: 1.6; }
.footer-links { border-top: 1px solid #e2e8f0; padding-top: 18px; margin-top: 18px; display: flex; gap: 20px; flex-wrap: wrap; }
.site-footer a { color: #475569; }

/* ===== Responsive ===== */
@media (max-width: 768px) {
    .hero h1 { font-size: 38px; }
    .hero .tagline { font-size: 19px; }
    .section h2 { font-size: 29px; }
    .article-page h1 { font-size: 26px; }
    .feature-grid, .product-grid, .faq-grid { grid-template-columns: 1fr; }
    .nav-inner nav ul { gap: 12px; }
    .nav-inner nav a { font-size: 11px; }
}