/* --- 基础布局 --- */
body {
    margin: 0; font-family: -apple-system, "Helvetica Neue", Arial, sans-serif;
    background-color: #f4f7fa; line-height: 1.6; color: #333;
}

/* --- 导航栏修复 --- */
.navbar {
    background: #fff; box-shadow: 0 2px 8px rgba(0,0,0,0.06);
    height: 60px; display: flex; align-items: center; position: sticky; top: 0; z-index: 1000;
}
.nav-container {
    width: 1000px; max-width: 95%; margin: 0 auto;
    display: flex; justify-content: space-between; align-items: center;
}
.brand { font-size: 20px; font-weight: 700; color: #007bff; }
.nav-right-area, .nav-links { display: flex; align-items: center; }
.nav-links a { text-decoration: none; color: #555; font-size: 14px; margin-right: 20px; transition: color 0.2s; }
.nav-links a:hover { color: #007bff; }
.lang-select { padding: 4px 8px; border-radius: 4px; border: 1px solid #ddd; font-size: 13px; cursor: pointer; }

/* --- 容器与主卡片 --- */
.main-container { max-width: 900px; margin: 40px auto; padding: 0 15px; }
.content-card { background: #fff; padding: 30px; border-radius: 12px; box-shadow: 0 5px 25px rgba(0,0,0,0.07); }
.page-title { text-align: center; margin-bottom: 30px; font-weight: 700; color: #2d3748; }

/* --- 首页播放器区域 --- */
.input-group { display: flex; gap: 10px; margin-bottom: 25px; }
.url-input { flex: 1; padding: 12px; border: 2px solid #f0f4f8; border-radius: 8px; outline: none; transition: border-color 0.2s; }
.url-input:focus { border-color: #007bff; }
.play-btn { background: #007bff; color: #fff; border: none; padding: 12px 30px; border-radius: 8px; cursor: pointer; font-weight: 600; }
.player-box { padding: 10px; background: #fafbfc; border-radius: 10px; border: 1px solid #edf2f7; margin-bottom: 30px; }

/* --- 关于页专用：知识卡片效果 (重点修复) --- */
.info-section { 
    margin-bottom: 30px; 
    padding: 25px; 
    background: #fff; 
    border-radius: 10px; 
    border: 1px solid #e2e8f0;
    box-shadow: 0 2px 4px rgba(0,0,0,0.02);
}
.info-section h2 { 
    font-size: 1.4rem; 
    color: #2d3748; 
    margin-top: 0; 
    display: flex; 
    align-items: center;
    border-left: 5px solid #007bff; /* 蓝色强调条 */
    padding-left: 15px;
}
.info-section p { color: #4a5568; font-size: 1.05rem; }

/* --- FAQ 网格布局 --- */
.faq-grid { display: grid; gap: 20px; margin-top: 20px; }
.faq-item { 
    background: #f8fafc; 
    padding: 20px; 
    border-radius: 8px; 
    border: 1px solid #edf2f7;
    transition: all 0.3s ease;
}
.faq-item:hover { transform: translateY(-3px); box-shadow: 0 4px 12px rgba(0,0,0,0.05); border-color: #007bff; }
.faq-item h3 { margin: 0 0 10px 0; font-size: 1.15rem; color: #2d3748; }
.faq-item p { margin: 0; font-size: 0.95rem; color: #718096; }

/* --- 首页详情区功能网格 --- */
.video-info-section { margin-top: 35px; border-top: 1px solid #edf2f7; }
.info-tabs { margin-top: -2px; border-top: 3px solid #007bff; display: inline-block; padding: 10px 15px 0 0; }
.tab-item.active { font-weight: 700; font-size: 16px; color: #2d3748; }
.feature-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(250px, 1fr)); gap: 20px; margin-top: 25px; }
.feature-item { display: flex; background: #fcfdfe; padding: 18px; border-radius: 10px; border: 1px solid #f0f4f8; }
.f-icon { font-size: 24px; margin-right: 15px; }
.f-text h4 { margin: 0 0 5px 0; font-size: 16px; color: #2d3748; }
.f-text p { margin: 0; font-size: 13px; color: #718096; }