/* ===================================
   DENBA Health — Official Website
   Light Tech Theme
   =================================== */

/* === CSS Variables === */
:root {
    --primary: #2563eb;
    --primary-dark: #1d4ed8;
    --primary-light: #3b82f6;
    --accent: #d97706;
    --accent-light: #f59e0b;
    --bg: #ffffff;
    --bg-alt: #f8fafb;
    --bg-card: #ffffff;
    --bg-section: #f3f5f6;
    --text: #0f172a;
    --text-secondary: #475569;
    --text-muted: #94a3b8;
    --border: #e2e8f0;
    --border-light: #cbd5e1;
    --radius: 10px;
    --radius-lg: 16px;
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.04);
    --shadow: 0 4px 24px rgba(0,0,0,0.06);
    --shadow-lg: 0 8px 40px rgba(0,0,0,0.08);
    --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --max-width: 1200px;
}

/* === Reset & Base === */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 80px; }
body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.7;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
}

.container { max-width: var(--max-width); margin: 0 auto; padding: 0 24px; }
a { text-decoration: none; color: inherit; }
ul { list-style: none; }
img { max-width: 100%; display: block; }

/* === Navigation === */
.navbar {
    position: fixed; top: 0; left: 0; right: 0; z-index: 1000;
    background: rgba(255,255,255,0.88);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--border);
    transition: var(--transition);
}
.navbar.scrolled { background: rgba(255,255,255,0.96); box-shadow: var(--shadow-sm); }
.nav-container { display: flex; align-items: center; justify-content: space-between; height: 68px; }
.nav-logo { display: flex; align-items: center; }
.logo-img { height: 36px; width: auto; display: block; }
.nav-menu { display: flex; gap: 4px; }
.nav-menu .nav-link {
    padding: 7px 18px; border-radius: 7px; font-size: 13px; font-weight: 500;
    color: var(--text-secondary); transition: var(--transition);
}
.nav-menu .nav-link:hover { color: var(--primary); background: rgba(37,99,235,0.04); }
.nav-menu .nav-link.active { color: var(--primary); background: rgba(37,99,235,0.06); font-weight: 600; }
.nav-toggle { display: none; flex-direction: column; gap: 5px; background: none; border: none; cursor: pointer; padding: 8px; }
.nav-toggle span { display: block; width: 22px; height: 2px; background: var(--text); border-radius: 2px; transition: var(--transition); }

/* === Hero === */
.hero {
    position: relative; min-height: 100vh; display: flex; align-items: center; justify-content: center;
    text-align: center; overflow: hidden;
    background: linear-gradient(180deg, #f8fafb 0%, #ffffff 40%, #ffffff 100%);
}
.hero-bg { position: absolute; inset: 0; overflow: hidden; }
.hero-canvas { position: absolute; inset: 0; width: 100%; height: 100%; z-index: 1; pointer-events: none; }
.hero-glow {
    position: absolute; border-radius: 50%; filter: blur(100px); opacity: 0.3; z-index: 0;
}
.hero-glow-1 { width: 500px; height: 500px; background: rgba(37,99,235,0.12); top: -10%; left: 50%; transform: translateX(-50%); }
.hero-glow-2 { width: 300px; height: 300px; background: rgba(217,119,6,0.06); bottom: 15%; right: 5%; }
.hero-grid {
    position: absolute; inset: 0; z-index: 0;
    background-image:
        linear-gradient(rgba(37,99,235,0.03) 1px, transparent 1px),
        linear-gradient(90deg, rgba(37,99,235,0.03) 1px, transparent 1px);
    background-size: 60px 60px;
}
.hero-content { position: relative; z-index: 2; max-width: 800px; }
.hero-tag {
    display: inline-block; padding: 5px 18px; border: 1px solid rgba(37,99,235,0.25);
    border-radius: 50px; font-size: 12px; color: var(--primary); letter-spacing: 3px;
    margin-bottom: 24px; animation: fadeInUp 0.8s ease;
}
.hero-title {
    font-size: clamp(48px, 8vw, 76px); font-weight: 900; line-height: 1.12;
    margin-bottom: 28px; letter-spacing: -1px; color: var(--text);
    animation: fadeInUp 0.8s ease 0.1s both;
}
.text-accent { color: var(--primary); }
.hero-desc {
    font-size: 18px; color: var(--text-secondary); line-height: 1.8; margin-bottom: 40px;
    animation: fadeInUp 0.8s ease 0.2s both;
}
.hero-btns { display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; animation: fadeInUp 0.8s ease 0.3s both; }
.hero-scroll {
    position: absolute; bottom: 40px; left: 50%; transform: translateX(-50%);
    display: flex; flex-direction: column; align-items: center; gap: 8px;
    color: var(--text-muted); font-size: 12px; letter-spacing: 2px;
}
.scroll-text { font-size: 11px; letter-spacing: 3px; }
.scroll-line { width: 1px; height: 40px; background: linear-gradient(to bottom, var(--text-muted), transparent); }

@keyframes fadeInUp { from { opacity: 0; transform: translateY(24px); } to { opacity: 1; transform: translateY(0); } }

/* === Buttons === */
.btn { display: inline-block; padding: 13px 34px; border-radius: 50px; font-size: 15px; font-weight: 600; cursor: pointer; transition: var(--transition); border: none; letter-spacing: 0.5px; }
.btn-primary { background: linear-gradient(135deg, var(--primary), var(--primary-dark)); color: #fff; box-shadow: 0 4px 16px rgba(37,99,235,0.2); }
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 6px 24px rgba(37,99,235,0.3); }
.btn-outline { border: 2px solid var(--border); color: var(--text); background: transparent; }
.btn-outline:hover { border-color: var(--primary-light); color: var(--primary); background: rgba(37,99,235,0.03); }
.btn-block { width: 100%; }

/* === Sections === */
.section { padding: 100px 0; background: var(--bg); }
.section-alt { background: var(--bg-alt); }
.section-header { text-align: center; margin-bottom: 64px; }
.section-label {
    display: inline-block; padding: 4px 16px; border: 1px solid rgba(37,99,235,0.2);
    border-radius: 50px; font-size: 11px; color: var(--primary); letter-spacing: 3px; margin-bottom: 20px;
}
.section-title { font-size: clamp(28px, 4vw, 40px); font-weight: 800; margin-bottom: 12px; letter-spacing: -0.5px; color: var(--text); }
.section-desc { font-size: 16px; color: var(--text-secondary); max-width: 600px; margin: 0 auto; line-height: 1.8; }

/* === Tech Canvas === */
.tech-canvas { position: absolute; inset: 0; width: 100%; height: 100%; z-index: 0; pointer-events: none; opacity: 0.5; }

/* === Image Placeholders === */
.image-placeholder {
    background: var(--bg-alt); border: 1px dashed var(--border);
    border-radius: var(--radius-lg); display: flex; align-items: center; justify-content: center;
    min-height: 200px; transition: var(--transition); margin-bottom: 48px;
}
.image-placeholder:hover { border-color: rgba(37,99,235,0.3); background: rgba(37,99,235,0.02); }
.img-placeholder-content { text-align: center; padding: 40px; }
.img-placeholder-icon { color: var(--text-muted); margin-bottom: 16px; opacity: 0.4; }
.img-placeholder-label { font-size: 15px; color: var(--text-secondary); margin-bottom: 8px; font-weight: 500; }
.img-placeholder-hint { font-size: 12px; color: var(--text-muted); }
.product-img-slot {
    background: var(--bg-alt); border: 1px dashed var(--border);
    border-radius: var(--radius); padding: 40px 20px; text-align: center;
    margin-top: 24px; font-size: 12px; color: var(--text-muted);
}
.scenario-img { min-height: 220px; margin-bottom: 0; border-radius: var(--radius) var(--radius) 0 0; }
.about-hero-img { margin: 0 auto 48px; max-width: 900px; min-height: 300px; }
.tech-diagram { max-width: 900px; margin: 0 auto 48px; min-height: 250px; }
.product-lineup { max-width: 1000px; margin: 0 auto 48px; }
.brand-hero { max-width: 1000px; margin: 0 auto 40px; min-height: 300px; }
.cert-map { max-width: 800px; margin: 0 auto 48px; min-height: 250px; }
.cert-placeholder { min-height: 180px; margin-bottom: 0; flex: 1; }

/* === Brand Section === */
.brand-overview { max-width: 800px; margin: 0 auto 64px; text-align: center; }
.brand-overview h3 { font-size: 24px; color: var(--text); margin-bottom: 4px; }
.brand-subtitle { font-size: 14px; color: var(--text-muted); margin-bottom: 20px; }
.brand-overview p { font-size: 15px; color: var(--text-secondary); line-height: 1.9; }
.brand-stats-row { display: flex; justify-content: center; gap: 56px; margin-top: 32px; }
.brand-stat-num { display: block; font-size: 40px; font-weight: 900; color: var(--primary); }
.brand-stat-label { font-size: 13px; color: var(--text-muted); letter-spacing: 2px; }

/* === Timeline === */
.timeline-section { max-width: 800px; margin: 0 auto; }
.timeline-title { text-align: center; font-size: 20px; color: var(--text); margin-bottom: 40px; font-weight: 700; }
.timeline { position: relative; }
.timeline::before { content: ''; position: absolute; left: 100px; top: 0; bottom: 0; width: 1px; background: var(--border); }
.tl-item { display: flex; gap: 36px; margin-bottom: 24px; position: relative; }
.tl-year { width: 64px; text-align: right; font-size: 16px; font-weight: 800; color: var(--primary); flex-shrink: 0; padding-top: 2px; }
.tl-content { background: var(--bg); border: 1px solid var(--border); border-radius: var(--radius); padding: 16px 22px; flex: 1; box-shadow: var(--shadow-sm); }
.tl-content h4 { font-size: 15px; color: var(--text); margin-bottom: 3px; }
.tl-content p { font-size: 13px; color: var(--text-secondary); line-height: 1.7; }
.tl-item::after { content: ''; position: absolute; left: 96px; top: 10px; width: 8px; height: 8px; border-radius: 50%; background: var(--primary); border: 2px solid var(--bg); }

/* === About Section === */
.about-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 24px; }
.about-card {
    text-align: center; padding: 40px 28px; background: var(--bg);
    border: 1px solid var(--border); border-radius: var(--radius-lg);
    transition: var(--transition);
}
.about-card:hover { border-color: var(--primary-light); box-shadow: var(--shadow); transform: translateY(-2px); }
.about-card-icon { color: var(--primary); margin-bottom: 18px; opacity: 0.8; }
.about-card h3 { font-size: 18px; margin-bottom: 12px; color: var(--text); }
.about-card p { font-size: 14px; color: var(--text-secondary); line-height: 1.8; }

/* === Brand Banner === */
.brand-banner {
    background: linear-gradient(135deg, rgba(37,99,235,0.04), rgba(37,99,235,0.01));
    border-top: 1px solid var(--border); border-bottom: 1px solid var(--border);
    padding: 64px 0;
}
.brand-banner-content { display: flex; gap: 48px; align-items: center; flex-wrap: wrap; }
.brand-info { flex: 1; min-width: 300px; }
.brand-label {
    display: inline-block; padding: 3px 14px; border: 1px solid rgba(217,119,6,0.25);
    border-radius: 50px; font-size: 10px; color: var(--accent); letter-spacing: 3px; margin-bottom: 16px;
}
.brand-info h2 { font-size: 28px; font-weight: 800; margin-bottom: 16px; color: var(--text); }
.brand-info p { font-size: 15px; color: var(--text-secondary); line-height: 1.9; }
.brand-cert { flex-shrink: 0; width: 300px; }

/* === Tech Cards === */
.tech-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 24px; }
.tech-card {
    background: var(--bg); border: 1px solid var(--border);
    border-radius: var(--radius); padding: 32px 24px; position: relative; overflow: hidden;
    transition: var(--transition); box-shadow: var(--shadow-sm);
}
.tech-card:hover { border-color: var(--primary-light); transform: translateY(-2px); box-shadow: var(--shadow); }
.tech-card::before { content: ''; position: absolute; top: 0; left: 0; right: 0; height: 2px; background: linear-gradient(90deg, var(--primary), var(--accent-light)); opacity: 0; transition: var(--transition); }
.tech-card:hover::before { opacity: 1; }
.tech-num { font-size: 48px; font-weight: 900; color: rgba(37,99,235,0.06); position: absolute; top: 16px; right: 20px; }
.tech-card h4 { font-size: 18px; margin-bottom: 10px; color: var(--text); position: relative; }
.tech-card p { font-size: 14px; color: var(--text-secondary); position: relative; line-height: 1.8; }

/* === Product Cards === */
.product-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); gap: 32px; margin-bottom: 64px; }
.product-card {
    background: var(--bg); border: 1px solid var(--border);
    border-radius: var(--radius-lg); padding: 40px 28px 28px; position: relative;
    transition: var(--transition); display: flex; flex-direction: column; box-shadow: var(--shadow-sm);
}
.product-card:hover { border-color: var(--primary-light); transform: translateY(-4px); box-shadow: var(--shadow-lg); }
.product-card.featured { border-color: rgba(37,99,235,0.35); box-shadow: 0 0 0 1px rgba(37,99,235,0.1), var(--shadow); }
.product-card.featured::before { content: ''; position: absolute; top: -1px; left: -1px; right: -1px; height: 3px; background: linear-gradient(90deg, var(--primary), var(--accent-light)); border-radius: var(--radius-lg) var(--radius-lg) 0 0; }
.product-tier {
    display: inline-block; padding: 3px 14px; background: var(--bg-alt);
    border-radius: 50px; font-size: 11px; color: var(--text-muted); letter-spacing: 2px;
    margin-bottom: 16px; align-self: flex-start; border: 1px solid var(--border);
}
.product-tier.accent { background: rgba(37,99,235,0.06); color: var(--primary); border-color: rgba(37,99,235,0.2); }
.product-name { font-size: 22px; font-weight: 700; color: var(--text); margin-bottom: 2px; }
.product-subtitle { font-size: 12px; color: var(--primary); letter-spacing: 3px; text-transform: uppercase; margin-bottom: 16px; }
.product-desc { margin-bottom: 16px; }
.product-desc p { font-size: 13px; color: var(--text-secondary); line-height: 1.7; }
.product-specs { text-align: left; margin-bottom: 4px; flex: 1; }
.product-specs li { padding: 7px 0; font-size: 13px; color: var(--text-secondary); border-bottom: 1px solid var(--border); }
.product-specs li::before { content: ''; display: inline-block; width: 5px; height: 5px; border-radius: 50%; background: var(--primary-light); margin-right: 10px; vertical-align: middle; }

/* === Feature Grid === */
.feature-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 12px; max-width: 800px; margin: 0 auto; }
.feature-item { display: flex; align-items: center; gap: 10px; padding: 14px 18px; background: var(--bg); border: 1px solid var(--border); border-radius: 8px; font-size: 13px; color: var(--text-secondary); }
.feature-icon.check { width: 18px; height: 18px; border-radius: 50%; background: rgba(37,99,235,0.1); position: relative; flex-shrink: 0; }
.feature-icon.check::after { content: ''; position: absolute; top: 5px; left: 5px; width: 8px; height: 5px; border-left: 1.5px solid var(--primary); border-bottom: 1.5px solid var(--primary); transform: rotate(-45deg); }

/* === Research === */
.research-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(340px, 1fr)); gap: 24px; }
.research-card {
    background: var(--bg); border: 1px solid var(--border);
    border-radius: var(--radius); padding: 32px; transition: var(--transition); box-shadow: var(--shadow-sm);
}
.research-card:hover { border-color: var(--primary-light); box-shadow: var(--shadow); }
.research-tag {
    display: inline-block; background: rgba(217,119,6,0.06); color: var(--accent);
    padding: 2px 12px; border-radius: 50px; font-size: 11px; margin-bottom: 16px; letter-spacing: 1px;
    border: 1px solid rgba(217,119,6,0.15);
}
.research-card h3 { font-size: 18px; color: var(--text); margin-bottom: 4px; }
.research-sub { font-size: 13px; color: var(--text-muted); margin-bottom: 12px; }
.research-card p { font-size: 14px; color: var(--text-secondary); line-height: 1.8; }

/* === Certifications === */
.cert-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 16px; }
.cert-item {
    background: var(--bg); border: 1px solid var(--border);
    border-radius: var(--radius); padding: 24px; display: flex; align-items: center; gap: 16px;
    transition: var(--transition); box-shadow: var(--shadow-sm);
}
.cert-item:hover { border-color: var(--primary-light); box-shadow: var(--shadow); }
.cert-flag {
    width: 42px; height: 42px; border-radius: 10px; background: rgba(37,99,235,0.06);
    display: flex; align-items: center; justify-content: center;
    font-size: 11px; font-weight: 700; color: var(--primary); flex-shrink: 0; letter-spacing: 1px;
    border: 1px solid rgba(37,99,235,0.15);
}
.cert-info h4 { font-size: 14px; color: var(--text); margin-bottom: 2px; }
.cert-info span { font-size: 12px; color: var(--text-muted); }

/* === Scenario Cards === */
.scenario-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(320px, 1fr)); gap: 28px; }
.scenario-card { border-radius: var(--radius-lg); overflow: hidden; border: 1px solid var(--border); background: var(--bg); transition: var(--transition); box-shadow: var(--shadow-sm); }
.scenario-card:hover { border-color: var(--primary-light); transform: translateY(-2px); box-shadow: var(--shadow); }
.scenario-info { padding: 24px; }
.scenario-info h4 { font-size: 17px; color: var(--text); margin-bottom: 8px; }
.scenario-info p { font-size: 14px; color: var(--text-secondary); line-height: 1.7; }

/* === Stats Banner === */
.stats-banner {
    background: linear-gradient(135deg, #f0f7f6, #f8fafb);
    padding: 56px 0; border-top: 1px solid var(--border); border-bottom: 1px solid var(--border);
}
.stats-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 32px; text-align: center; }
.stat-number { display: block; font-size: 42px; font-weight: 900; color: var(--primary); }
.stat-label { font-size: 14px; color: var(--text-secondary); margin-top: 4px; letter-spacing: 1px; }

/* === Contact === */
.contact-grid { display: grid; grid-template-columns: 1fr 1.5fr; gap: 48px; align-items: start; }
.contact-item { display: flex; gap: 16px; margin-bottom: 32px; }
.contact-icon { color: var(--primary); flex-shrink: 0; margin-top: 2px; }
.contact-item h4 { font-size: 16px; color: var(--text); margin-bottom: 4px; }
.contact-item p { font-size: 14px; color: var(--text-secondary); }
.contact-form-wrapper { background: var(--bg); border: 1px solid var(--border); border-radius: var(--radius-lg); padding: 40px; box-shadow: var(--shadow-sm); }
.form-row { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.form-group { margin-bottom: 20px; }
.form-group input, .form-group textarea, .form-group select {
    width: 100%; padding: 13px 16px; background: var(--bg-alt);
    border: 1px solid var(--border); border-radius: var(--radius);
    color: var(--text); font-size: 15px; font-family: inherit; transition: var(--transition);
}
.form-group input:focus, .form-group textarea:focus, .form-group select:focus { outline: none; border-color: var(--primary); background: #fff; }
.form-group textarea { resize: vertical; min-height: 120px; }
.form-group select { appearance: none; cursor: pointer; }
.form-group select option { background: #fff; color: var(--text); }

/* === Footer === */
.footer { background: #f8fafb; border-top: 1px solid var(--border); padding: 64px 0 32px; }
.footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr; gap: 48px; margin-bottom: 40px; }
.footer-brand h3 { font-size: 22px; margin-bottom: 4px; color: var(--text); }
.footer-tagline { font-size: 13px; color: var(--text-muted); line-height: 1.7; margin-top: 4px; }
.footer-links h4 { font-size: 14px; color: var(--text); margin-bottom: 16px; text-transform: uppercase; letter-spacing: 2px; }
.footer-links li { margin-bottom: 8px; }
.footer-links a, .footer-links span { font-size: 14px; color: var(--text-muted); transition: var(--transition); }
.footer-links a:hover { color: var(--primary); }
.footer-bottom { padding-top: 24px; border-top: 1px solid var(--border); text-align: center; }
.footer-bottom p { font-size: 13px; color: var(--text-muted); }

/* === Responsive === */
@media (max-width: 1024px) {
    .contact-grid { grid-template-columns: 1fr; }
    .footer-grid { grid-template-columns: 1fr 1fr; }
    .stats-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 768px) {
    .nav-menu {
        position: fixed; top: 68px; left: 0; right: 0; bottom: 0;
        background: rgba(255,255,255,0.98); backdrop-filter: blur(20px);
        flex-direction: column; align-items: center; justify-content: center;
        gap: 16px; transform: translateX(100%); transition: var(--transition);
    }
    .nav-menu.open { transform: translateX(0); }
    .nav-menu .nav-link { font-size: 18px; padding: 12px 24px; }
    .nav-toggle { display: flex; }
    .nav-toggle span { background: var(--text); }
    .section { padding: 72px 0; }
    .hero-title { font-size: 38px; }
    .timeline::before { left: 16px; }
    .tl-item { flex-direction: column; gap: 8px; padding-left: 32px; }
    .tl-year { text-align: left; width: auto; }
    .tl-item::after { left: 13px; top: 8px; }
    .footer-grid { grid-template-columns: 1fr; gap: 32px; }
    .feature-grid { grid-template-columns: repeat(2, 1fr); }
    .stats-grid { grid-template-columns: repeat(2, 1fr); gap: 24px; }
    .stat-number { font-size: 32px; }
    .form-row { grid-template-columns: 1fr; }
    .brand-banner-content { flex-direction: column; }
    .brand-cert { width: 100%; }
}

@media (max-width: 480px) {
    .hero-tag { letter-spacing: 2px; font-size: 11px; }
    .hero-title { font-size: 30px; }
    .hero-desc { font-size: 15px; }
    .hero-btns { flex-direction: column; align-items: center; }
    .feature-grid { grid-template-columns: 1fr; }
    .product-grid, .research-grid, .scenario-grid { grid-template-columns: 1fr; }
    .cert-grid { grid-template-columns: repeat(2, 1fr); }
    .about-grid { grid-template-columns: 1fr; }
}