:root {
    --primary-color: #e50012; /* Netease red as an accent, or Youdao red */
    --secondary-color: #2b2b2b;
    --bg-color: #f7f9fa;
    --text-color: #333;
    --link-color: #1a73e8;
}

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

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

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

/* Header & Nav */
.header {
    background-color: #fff;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    position: sticky;
    top: 0;
    z-index: 100;
}

.nav-bar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.logo h1 {
    font-size: 24px;
    color: var(--secondary-color);
}

.logo span {
    color: var(--primary-color);
    font-size: 14px;
    vertical-align: super;
}

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

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

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

/* Hero Section */
.hero-section {
    background: linear-gradient(135deg, #1e3c72 0%, #2a5298 100%);
    color: #fff;
    padding: 80px 0;
    text-align: center;
}

.hero-text h2 {
    font-size: 48px;
    margin-bottom: 20px;
}

.hero-text p {
    font-size: 18px;
    max-width: 800px;
    margin: 0 auto 30px;
    opacity: 0.9;
}

.download-box {
    margin-top: 40px;
}

.btn-primary, .btn-secondary {
    display: inline-block;
    padding: 15px 30px;
    border-radius: 30px;
    text-decoration: none;
    font-size: 18px;
    font-weight: bold;
    margin: 10px;
    transition: transform 0.2s, box-shadow 0.2s;
}

.btn-primary {
    background-color: var(--primary-color);
    color: #fff;
    box-shadow: 0 4px 15px rgba(229, 0, 18, 0.4);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(229, 0, 18, 0.6);
}

.btn-secondary {
    background-color: transparent;
    border: 2px solid #fff;
    color: #fff;
}

.btn-secondary:hover {
    background-color: rgba(255,255,255,0.1);
}

.version-info {
    font-size: 14px;
    margin-top: 15px;
    opacity: 0.7;
}

/* Features */
.features-overview {
    padding: 60px 0;
    background-color: #fff;
}

.section-title {
    text-align: center;
    font-size: 32px;
    margin-bottom: 40px;
}

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

.feature-card {
    background: var(--bg-color);
    padding: 30px;
    border-radius: 10px;
    text-align: center;
    transition: transform 0.3s;
}

.feature-card:hover {
    transform: translateY(-5px);
}

.feature-card h4 {
    font-size: 20px;
    margin-bottom: 15px;
    color: var(--primary-color);
}

/* SEO Content */
.seo-content {
    padding: 40px 0;
}

.seo-content h3 {
    font-size: 24px;
    margin-bottom: 20px;
}

.seo-content p {
    margin-bottom: 15px;
    text-indent: 2em;
}

/* Inner Pages */
.inner-page {
    padding: 50px 0;
    background: #fff;
    min-height: 60vh;
}

.page-title {
    font-size: 36px;
    margin-bottom: 30px;
    border-bottom: 2px solid var(--primary-color);
    padding-bottom: 10px;
    display: inline-block;
}

.content-body h2 {
    margin: 30px 0 15px;
    color: var(--secondary-color);
}

.content-body p {
    margin-bottom: 20px;
    font-size: 16px;
}

.cta-banner {
    background: #f1f5fb;
    padding: 30px;
    text-align: center;
    border-radius: 10px;
    margin-top: 40px;
}

/* FAQ List */
.faq-list {
    max-width: 800px;
}

.faq-item {
    margin-bottom: 30px;
    border-bottom: 1px solid #eee;
    padding-bottom: 20px;
}

.faq-item h3 {
    font-size: 20px;
    color: var(--link-color);
    margin-bottom: 10px;
}

/* Footer */
footer {
    background-color: var(--secondary-color);
    color: #ccc;
    text-align: center;
    padding: 30px 0;
    margin-top: 40px;
}

footer a {
    color: #ccc;
    text-decoration: none;
}

footer a:hover {
    text-decoration: underline;
}

.disclaimer {
    font-size: 12px;
    margin-top: 10px;
    opacity: 0.6;
}

@media (max-width: 768px) {
    .nav-bar {
        flex-direction: column;
        height: auto;
        padding: 15px 0;
    }
    .nav-links {
        margin-top: 15px;
    }
    .hero-text h2 {
        font-size: 32px;
    }
}