/* Base Styles */
:root {
    --primary-color: #007bff;
    --secondary-color: #6c757d;
    --text-color: #333;
    --bg-color: #fff;
    --bg-light: #f8f9fa;
    --border-color: #ddd;
    --heading-color: #222;
}

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

body {
    font-family: "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--bg-color);
}

a {
    color: var(--primary-color);
    text-decoration: none;
    transition: color 0.3s;
}

a:hover {
    color: #0056b3;
}

.container {
    width: 90%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 15px;
}

/* Header */
.main-header {
    background: #fff;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.main-header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px;
}

.logo a {
    font-size: 24px;
    color: var(--heading-color);
    font-weight: bold;
}

.main-nav ul {
    list-style: none;
    display: flex;
    gap: 20px;
}

.main-nav a {
    color: var(--text-color);
    font-weight: 500;
    padding: 5px 10px;
}

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

/* Hero Section */
.hero-section {
    background: linear-gradient(135deg, #007bff 0%, #0056b3 100%);
    color: #fff;
    padding: 80px 0;
    text-align: center;
}

.hero-section h1 {
    font-size: 36px;
    margin-bottom: 20px;
}

.hero-subtitle {
    font-size: 18px;
    margin-bottom: 30px;
    max-width: 800px;
    margin-left: auto;
    margin-right: auto;
    opacity: 0.9;
}

.cta-buttons {
    display: flex;
    justify-content: center;
    gap: 20px;
}

.btn {
    display: inline-block;
    padding: 12px 24px;
    border-radius: 5px;
    font-weight: bold;
    text-align: center;
}

.btn-primary {
    background-color: #fff;
    color: var(--primary-color);
}
.btn-primary:hover {
    background-color: #f0f0f0;
    color: #004494;
}

.btn-secondary {
    background-color: transparent;
    color: #fff;
    border: 2px solid #fff;
}
.btn-secondary:hover {
    background-color: rgba(255,255,255,0.1);
    color: #fff;
}

.btn-large {
    font-size: 20px;
    padding: 15px 30px;
}

/* Content Sections */
section {
    padding: 60px 0;
}

.bg-light {
    background-color: var(--bg-light);
}

h2 {
    font-size: 28px;
    color: var(--heading-color);
    margin-bottom: 30px;
    text-align: center;
}

.content-block {
    max-width: 800px;
    margin: 0 auto;
    font-size: 16px;
}
.content-block p {
    margin-bottom: 15px;
}

/* Grid */
.grid-3 {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.card {
    background: #fff;
    padding: 30px;
    border-radius: 8px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.05);
    text-align: center;
}
.card h3 {
    font-size: 20px;
    margin-bottom: 15px;
    color: var(--primary-color);
}

/* Features List */
.feature-item {
    margin-bottom: 40px;
}
.feature-text h2 {
    text-align: left;
    font-size: 22px;
    color: var(--primary-color);
}
.feature-text p {
    margin-bottom: 15px;
}

/* Download Section */
.download-box {
    background: #fff;
    padding: 40px;
    border-radius: 10px;
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
    max-width: 600px;
    margin: 0 auto;
}
.version-info {
    text-align: left;
    margin-bottom: 30px;
}
.version-info h2 {
    font-size: 20px;
    text-align: left;
    margin-bottom: 15px;
}
.check-list {
    list-style: none;
    margin-top: 15px;
}
.check-list li {
    padding-left: 25px;
    position: relative;
    margin-bottom: 10px;
}
.check-list li::before {
    content: '✓';
    position: absolute;
    left: 0;
    color: #28a745;
    font-weight: bold;
}

/* FAQ */
.faq-item {
    margin-bottom: 25px;
}
.faq-item h3 {
    font-size: 18px;
    color: var(--heading-color);
    margin-bottom: 10px;
}

/* Footer */
.main-footer {
    background: #222;
    color: #ccc;
    text-align: center;
    padding: 30px 0;
}
.main-footer p {
    margin-bottom: 10px;
}

/* Mobile */
@media (max-width: 768px) {
    .main-header .container {
        flex-direction: column;
        gap: 15px;
    }
    .cta-buttons {
        flex-direction: column;
    }
}