/* Basic Layout / 基础布局 
*/
body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    margin: 0;
    padding: 0;
    line-height: 1.6;
    background-color: #f4f7f6;
}

/* Navigation Container / 导航容器
*/
.mega-nav {
    background: #2c3e50;
    color: white;
    padding: 0 5%;
}

.nav-list {
    display: flex;
    list-style: none;
    margin: 0;
    padding: 0;
}

.nav-list > li > a {
    display: block;
    padding: 20px 25px;
    color: white;
    text-decoration: none;
    transition: background 0.3s;
}

.nav-list > li > a:hover {
    background: #34495e;
}

/* Mega Menu Logic / 大型菜单逻辑 
   We hide the panel by default and show it on hover or focus-within.
   默认隐藏面板，在悬停或获得焦点时显示。
*/
.mega-panel {
    position: absolute;
    left: 0;
    width: 100%;
    background: white;
    color: #333;
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
    padding: 40px 10%;
    box-shadow: 0 10px 20px rgba(0,0,0,0.1);
    box-sizing: border-box;
    
    /* Hide the menu / 隐藏菜单 */
    visibility: hidden;
    opacity: 0;
    transform: translateY(10px);
    transition: all 0.3s ease;
    z-index: 100;
}

/* The 'Magic' Selectors / 核心选择器 
   No JS needed to show content.
*/
.mega-trigger:hover .mega-panel,
.mega-trigger:focus-within .mega-panel {
    visibility: visible;
    opacity: 1;
    transform: translateY(0);
}

/* Internal Menu Styling / 内部菜单样式
*/
.mega-column h3 {
    border-bottom: 2px solid #2c3e50;
    padding-bottom: 10px;
    font-size: 1.1rem;
}

.mega-column ul {
    list-style: none;
    padding: 0;
}

.mega-column ul li a {
    display: block;
    padding: 8px 0;
    color: #555;
    text-decoration: none;
}

.mega-column ul li a:hover {
    color: #2c3e50;
    text-decoration: underline;
}

/* Explanation Text Styling / 说明文字样式
*/
.explanation-section {
    max-width: 800px;
    margin: 50px auto;
    padding: 20px;
    background: white;
    border-radius: 8px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.05);
}

.promo {
    background: #f9f9f9;
    padding: 15px;
    border-radius: 5px;
}

/* SEO Insight Box Styling / SEO 见解区块样式 */
.seo-insight-box {
    max-width: 1000px;
    margin: 2rem auto;
    padding: 2rem;
    background: #ffffff;
    border-radius: 12px;
    border: 1px solid #e2e8f0; /* Matches your border-gray */
    box-shadow: 0 1px 3px rgba(0,0,0,0.1);
}

.seo-insight-box h2 {
    color: #2563eb; /* Matches your accent-blue */
    font-size: 1.5rem;
    margin-top: 0;
    margin-bottom: 1.5rem;
    border-bottom: 2px solid #f1f5f9;
    padding-bottom: 0.5rem;
}

.insight-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
}

.seo-insight-box article h3 {
    font-size: 1.1rem;
    margin-bottom: 1rem;
    color: #0f172a;
}

.seo-insight-box p {
    font-size: 0.95rem;
    line-height: 1.6;
    margin-bottom: 1rem;
    color: #1e293b;
}

.seo-insight-box p[lang="zh"] {
    color: #64748b;
    font-size: 0.9rem;
    border-left: 3px solid #eff6ff;
    padding-left: 1rem;
}

@media (max-width: 768px) {
    .insight-grid { grid-template-columns: 1fr; }
}

/* Footer Styling */
.pattern-footer {
    max-width: 1000px;
    margin: 4rem auto;
    padding: 2rem 1rem;
    text-align: center;
}

.back-nav a {
    color: var(--accent-blue);
    text-decoration: none;
    font-weight: 600;
}

.corporate-links {
    margin-top: 2rem;
    font-size: 0.9rem;
    color: #64748b;
}

.corporate-links a {
    color: var(--accent-blue);
    text-decoration: none;
}

@media (max-width: 768px) {
    .insight-grid { grid-template-columns: 1fr; }
}