/* Reset & Base Styles */
:root {
    --primary-color: #0052cc;
    --primary-hover: #0043a6;
    --secondary-color: #f4f5f7;
    --secondary-hover: #ebecf0;
    --text-main: #172b4d;
    --text-muted: #5e6c84;
    --bg-light: #ffffff;
    --bg-gray: #f8f9fa;
    --border-color: #dfe1e6;
    --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
    --shadow-md: 0 4px 6px rgba(0,0,0,0.05), 0 1px 3px rgba(0,0,0,0.1);
    --shadow-lg: 0 10px 20px rgba(0,0,0,0.08);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Microsoft YaHei", sans-serif;
    line-height: 1.6;
    color: var(--text-main);
    background-color: var(--bg-light);
    -webkit-font-smoothing: antialiased;
}

a {
    text-decoration: none;
    color: var(--primary-color);
    transition: color 0.2s ease;
}

ul {
    list-style: none;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

/* Header */
.header {
    background: var(--bg-light);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: var(--shadow-sm);
}

.header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 72px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 22px;
    font-weight: 700;
    color: var(--primary-color);
}

.nav ul {
    display: flex;
    align-items: center;
    gap: 32px;
}

.nav a {
    color: var(--text-main);
    font-weight: 500;
}

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

.btn-nav-download {
    background: var(--primary-color);
    color: white !important;
    padding: 8px 20px;
    border-radius: 6px;
    font-weight: 600;
}

.btn-nav-download:hover {
    background: var(--primary-hover);
}

/* Hero Section */
.hero {
    padding: 80px 0;
    background: linear-gradient(135deg, #f0f4f8 0%, #ffffff 100%);
    overflow: hidden;
}

.hero-content {
    display: flex;
    align-items: center;
    gap: 60px;
}

.hero-text {
    flex: 1;
}

.hero-text h1 {
    font-size: 48px;
    line-height: 1.2;
    margin-bottom: 24px;
    color: var(--text-main);
    letter-spacing: -0.5px;
}

.subtitle {
    font-size: 20px;
    color: var(--text-muted);
    margin-bottom: 40px;
    max-width: 540px;
}

.download-buttons {
    display: flex;
    gap: 20px;
    margin-bottom: 16px;
    flex-wrap: wrap;
}

.btn {
    display: inline-flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 16px 32px;
    border-radius: 8px;
    font-size: 18px;
    font-weight: 600;
    text-align: center;
    transition: all 0.3s ease;
    min-width: 220px;
    position: relative;
}

.btn svg {
    margin-bottom: 8px;
}

.version-info {
    font-size: 12px;
    font-weight: 400;
    opacity: 0.8;
    margin-top: 4px;
}

.btn-primary {
    background: var(--primary-color);
    color: white;
    box-shadow: 0 4px 14px rgba(0, 82, 204, 0.3);
}

.btn-primary:hover {
    background: var(--primary-hover);
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(0, 82, 204, 0.4);
    color: white;
}

.btn-secondary {
    background: var(--bg-light);
    color: var(--text-main);
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-sm);
}

.btn-secondary:hover {
    background: var(--secondary-hover);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
    color: var(--text-main);
}

.safe-note {
    font-size: 14px;
    color: #36b37e;
    font-weight: 500;
}

.hero-image {
    flex: 1;
    display: flex;
    justify-content: center;
}

.hero-image img {
    max-width: 100%;
    height: auto;
    filter: drop-shadow(0 20px 40px rgba(0,0,0,0.1));
}

/* Features Section */
.features {
    padding: 80px 0;
    background: var(--bg-light);
}

.section-title {
    text-align: center;
    font-size: 36px;
    margin-bottom: 60px;
    color: var(--text-main);
}

.feature-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 40px;
}

.feature-card {
    text-align: center;
    padding: 40px 24px;
    background: var(--bg-light);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
    border-color: transparent;
}

.feature-card img {
    margin-bottom: 24px;
}

.feature-card h3 {
    font-size: 22px;
    margin-bottom: 16px;
}

.feature-card p {
    color: var(--text-muted);
    font-size: 16px;
}

/* SEO Content Section */
.seo-content {
    padding: 60px 0;
    background: var(--bg-gray);
    border-top: 1px solid var(--border-color);
}

.seo-content h2 {
    font-size: 28px;
    margin-bottom: 40px;
    text-align: center;
}

.faq-item {
    background: var(--bg-light);
    padding: 32px;
    border-radius: 8px;
    margin-bottom: 24px;
    box-shadow: var(--shadow-sm);
}

.faq-item h3 {
    font-size: 20px;
    margin-bottom: 12px;
    color: var(--primary-color);
}

.faq-item p {
    color: var(--text-muted);
}

/* Footer */
.footer {
    background: #091e42;
    color: #a5adba;
    padding: 60px 0 24px;
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 40px;
    padding-bottom: 40px;
    border-bottom: 1px solid rgba(255,255,255,0.1);
}

.footer-logo {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 24px;
    font-weight: 700;
    color: white;
}

.footer-links {
    display: flex;
    gap: 24px;
}

.footer-links a {
    color: #a5adba;
}

.footer-links a:hover {
    color: white;
}

.footer-bottom {
    text-align: center;
    font-size: 14px;
}

.footer-bottom p {
    margin-bottom: 8px;
}

/* Responsive */
@media (max-width: 992px) {
    .hero-content {
        flex-direction: column;
        text-align: center;
    }
    .subtitle {
        margin: 0 auto 40px;
    }
    .download-buttons {
        justify-content: center;
    }
    .feature-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 768px) {
    .nav ul {
        display: none; /* Simple mobile nav hide for landing page */
    }
    .hero-text h1 {
        font-size: 36px;
    }
    .feature-grid {
        grid-template-columns: 1fr;
    }
    .footer-content {
        flex-direction: column;
        gap: 24px;
    }
}