:root {
    --primary: #2563eb;
    --primary-dark: #1d4ed8;
    --accent: #f59e0b;
    --text-main: #0f172a;
    --text-muted: #64748b;
    --bg-main: #ffffff;
    --bg-offset: #f8fafc;
    --container: 1200px;
    --radius: 12px;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Noto Sans SC', 'Poppins', sans-serif;
    color: var(--text-main);
    background: var(--bg-main);
    line-height: 1.6;
    scroll-behavior: smooth;
}

.container {
    max-width: var(--container);
    margin: 0 auto;
    padding: 0 24px;
}

/* Header */
.header {
    height: 80px;
    display: flex;
    align-items: center;
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(10px);
    position: sticky;
    top: 0;
    z-index: 100;
    border-bottom: 1px solid #f1f5f9;
}

.nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    width: 100%;
}

.logo {
    font-size: 24px;
    font-weight: 800;
    color: var(--primary);
}

.logo span {
    color: var(--text-muted);
    font-size: 14px;
    margin-left: 4px;
    vertical-align: super;
}

.nav-links {
    display: flex;
    gap: 32px;
    list-style: none;
}

.nav-links a {
    text-decoration: none;
    color: var(--text-main);
    font-weight: 500;
    transition: color 0.3s;
}

.nav-links a:hover {
    color: var(--primary);
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 12px 28px;
    border-radius: var(--radius);
    font-weight: 600;
    text-decoration: none;
    transition: all 0.3s;
    cursor: pointer;
    border: none;
}

.btn-primary {
    background: var(--primary);
    color: white;
    box-shadow: 0 4px 12px rgba(37, 99, 235, 0.2);
}

.btn-primary:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: 0 6px 16px rgba(37, 99, 235, 0.3);
}

.btn-outline {
    background: white;
    color: var(--primary);
    border: 2px solid var(--primary);
}

.btn-outline:hover {
    background: #eff6ff;
}

.btn-lg {
    padding: 16px 40px;
    font-size: 18px;
}

.btn-block {
    width: 100%;
}

/* Hero */
.hero {
    padding: 120px 0 80px;
    background: radial-gradient(circle at top right, #eff6ff, transparent);
    text-align: center;
}

.hero-title {
    font-size: 56px;
    font-weight: 800;
    letter-spacing: -0.02em;
    margin-bottom: 24px;
    background: linear-gradient(135deg, #1e293b 0%, #3b82f6 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero-subtitle {
    font-size: 20px;
    color: var(--text-muted);
    max-width: 720px;
    margin: 0 auto 48px;
}

.hero-btns {
    display: flex;
    justify-content: center;
    gap: 20px;
    margin-bottom: 64px;
}

.hero-stats {
    display: flex;
    justify-content: center;
    gap: 40px;
    color: var(--text-muted);
    font-weight: 500;
}

/* Features */
.features {
    padding: 100px 0;
}

.section-title {
    font-size: 36px;
    text-align: center;
    margin-bottom: 60px;
    font-weight: 800;
}

.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 32px;
}

.feature-card {
    padding: 48px 32px;
    background: var(--bg-offset);
    border-radius: var(--radius);
    text-align: center;
    transition: transform 0.3s, background 0.3s;
}

.feature-card:hover {
    transform: translateY(-8px);
    background: white;
    box-shadow: 0 20px 40px rgba(0,0,0,0.05);
}

.feature-icon {
    font-size: 48px;
    margin-bottom: 24px;
}

.feature-card h3 {
    margin-bottom: 16px;
    font-size: 20px;
}

/* Safe Banner */
.safe-banner {
    padding: 60px 0;
    background: #10b981;
    color: white;
    text-align: center;
}

.safe-content h2 {
    font-size: 32px;
    margin-bottom: 16px;
}

/* Download */
.download-section {
    padding: 100px 0;
    background: #0f172a;
}

.text-white { color: white; }

.download-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
    gap: 40px;
    margin-top: 60px;
}

.download-card {
    background: white;
    padding: 56px 40px;
    border-radius: 24px;
    text-align: center;
    position: relative;
}

.download-card.featured {
    border: 4px solid var(--primary);
}

.badge {
    position: absolute;
    top: 24px;
    right: 24px;
    background: var(--accent);
    color: white;
    padding: 6px 14px;
    border-radius: 99px;
    font-size: 14px;
    font-weight: 700;
}

.download-features {
    text-align: left;
    margin: 32px 0;
    list-style: none;
}

.download-features li {
    margin-bottom: 12px;
    display: flex;
    align-items: center;
    gap: 8px;
}

/* Footer */
.footer {
    padding: 80px 0 40px;
    background: var(--bg-offset);
    border-top: 1px solid #e2e8f0;
}

.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr;
    gap: 60px;
    margin-bottom: 60px;
}

.footer-bottom {
    text-align: center;
    padding-top: 40px;
    border-top: 1px solid #e2e8f0;
    color: var(--text-muted);
}

.seo-footer {
    margin-top: 16px;
}

.seo-footer a {
    color: var(--text-muted);
    margin: 0 4px;
    text-decoration: none;
}

@media (max-width: 768px) {
    .hero-title { font-size: 36px; }
    .nav-links, .nav-cta { display: none; }
    .footer-grid { grid-template-columns: 1fr; }
}