:root {
    --primary: #0a4d68;
    --secondary: #ff6b6b;
    --accent: #4ecdc4;
    --dark: #1a2332;
    --light: #f8f9fa;
    --text: #2d3748;
    --text-light: #718096;
    --border: #e2e8f0;
    --shadow: rgba(10, 77, 104, 0.1);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans SC", "Microsoft YaHei", sans-serif;
    color: var(--text);
    line-height: 1.6;
    background: var(--light);
}

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

/* Header */
header {
    background: #fff;
    box-shadow: 0 2px 10px var(--shadow);
    position: sticky;
    top: 0;
    z-index: 100;
}

header nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 0;
}

.logo img {
    height: 45px;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 2.5rem;
}

.nav-menu a {
    text-decoration: none;
    color: var(--text);
    font-size: 17px;
    font-weight: 500;
    transition: color 0.3s;
    position: relative;
}

.nav-menu a::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--accent);
    transition: width 0.3s;
}

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

.nav-menu a:hover::after {
    width: 100%;
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, #0a4d68 0%, #1a6b8a 100%);
    color: #fff;
    padding: 80px 0;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,<svg width="60" height="60" xmlns="http://www.w3.org/2000/svg"><path d="M0 0h60v60H0z" fill="none"/><path d="M30 0l30 30-30 30L0 30z" fill="rgba(255,255,255,0.03)"/></svg>');
    opacity: 0.4;
}

.hero .container {
    position: relative;
    z-index: 1;
}

.hero h1 {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 1rem;
    animation: fadeInUp 0.8s ease;
}

.hero-subtitle {
    font-size: 1.3rem;
    margin-bottom: 2.5rem;
    opacity: 0.95;
    animation: fadeInUp 0.8s ease 0.2s backwards;
}

.hero-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 3rem;
    align-items: center;
    animation: fadeInUp 0.8s ease 0.4s backwards;
}

.hero-text p {
    font-size: 1.05rem;
    line-height: 1.8;
    margin-bottom: 2rem;
    opacity: 0.9;
}

.hero-image img {
    width: 100%;
    border-radius: 12px;
    box-shadow: 0 20px 60px rgba(0,0,0,0.3);
}

/* Buttons */
.btn-primary {
    display: inline-block;
    background: var(--secondary);
    color: #fff;
    padding: 14px 32px;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 600;
    font-size: 1.1rem;
    transition: all 0.3s;
    box-shadow: 0 4px 15px rgba(255, 107, 107, 0.3);
}

.btn-primary:hover {
    background: #ff5252;
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(255, 107, 107, 0.4);
}

/* Features Section */
.features {
    padding: 80px 0;
    background: #fff;
}

.features h2 {
    text-align: center;
    font-size: 2.5rem;
    color: var(--primary);
    margin-bottom: 3rem;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.feature-card {
    background: var(--light);
    padding: 2rem;
    border-radius: 12px;
    transition: all 0.3s;
    border: 2px solid transparent;
}

.feature-card:hover {
    transform: translateY(-5px);
    border-color: var(--accent);
    box-shadow: 0 10px 30px var(--shadow);
}

.feature-card i {
    font-size: 2.5rem;
    color: var(--accent);
    margin-bottom: 1rem;
}

.feature-card h3 {
    font-size: 1.4rem;
    color: var(--primary);
    margin-bottom: 1rem;
}

.feature-card p {
    color: var(--text-light);
    line-height: 1.7;
}

/* Stats Section */
.stats {
    background: linear-gradient(135deg, var(--primary) 0%, #1a6b8a 100%);
    color: #fff;
    padding: 60px 0;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 2rem;
    text-align: center;
}

.stat-item i {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    color: var(--accent);
}

.stat-item h3 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.stat-item p {
    font-size: 1.1rem;
    opacity: 0.9;
}

/* Download CTA */
.download-cta {
    background: var(--light);
    padding: 80px 0;
    text-align: center;
}

.download-cta h2 {
    font-size: 2.5rem;
    color: var(--primary);
    margin-bottom: 1rem;
}

.download-cta p {
    font-size: 1.2rem;
    color: var(--text-light);
    margin-bottom: 2rem;
}

/* Footer */
footer {
    background: var(--dark);
    color: #fff;
    padding: 50px 0 20px;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;
}

.footer-section h4 {
    font-size: 1.2rem;
    margin-bottom: 1rem;
    color: var(--accent);
}

.footer-section ul {
    list-style: none;
}

.footer-section ul li {
    margin-bottom: 0.5rem;
}

.footer-section a {
    color: rgba(255,255,255,0.8);
    text-decoration: none;
    transition: color 0.3s;
}

.footer-section a:hover {
    color: var(--accent);
}

.footer-bottom {
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid rgba(255,255,255,0.1);
    color: rgba(255,255,255,0.6);
}

/* Animations */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Download Page Specific */
.download-hero {
    background: linear-gradient(135deg, #0a4d68 0%, #1a6b8a 100%);
    color: #fff;
    padding: 60px 0;
    text-align: center;
}

.download-hero h1 {
    font-size: 2.8rem;
    margin-bottom: 1rem;
}

.download-section {
    padding: 60px 0;
}

.download-box {
    background: #fff;
    border-radius: 12px;
    padding: 3rem;
    box-shadow: 0 10px 40px var(--shadow);
    max-width: 700px;
    margin: 0 auto;
}

.download-box h2 {
    color: var(--primary);
    margin-bottom: 1.5rem;
}

.download-info {
    background: var(--light);
    padding: 1.5rem;
    border-radius: 8px;
    margin: 1.5rem 0;
}

.download-info p {
    margin-bottom: 0.8rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.download-info i {
    color: var(--accent);
}

.system-requirements {
    margin-top: 2rem;
}

.system-requirements h3 {
    color: var(--primary);
    margin-bottom: 1rem;
}

.system-requirements ul {
    list-style: none;
    padding-left: 0;
}

.system-requirements li {
    padding: 0.5rem 0;
    padding-left: 1.5rem;
    position: relative;
}

.system-requirements li::before {
    content: '✓';
    position: absolute;
    left: 0;
    color: var(--accent);
    font-weight: bold;
}

/* Responsive */
@media (max-width: 768px) {
    .hero-content {
        grid-template-columns: 1fr;
    }

    .hero h1 {
        font-size: 2rem;
    }

    .nav-menu {
        gap: 1rem;
        font-size: 15px;
    }

    .features-grid {
        grid-template-columns: 1fr;
    }
}