/* 全局样式：重置默认样式 */{
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

/* 基本样式：接近黑色的深蓝，调整配色 */
body {
    font-family: 'Lato', sans-serif;
    color: #F9FAFB; /* 灰白文字 */
    background-color: #0F172A; /* 接近黑色的深蓝 */
}a {
    text-decoration: none;
    color: #93C5FD; /* 柔和冷蓝链接 */
}a:hover {
    color: #60A5FA; /* 亮蓝悬停 */
}/* 头部：Logo 和导航栏 */
header {
    background-color: #0F172A;
    padding: 20px;
    text-align: center;
    position: sticky;
    top: 0;
    z-index: 100;
}header img {
    max-width: 150px;
    height: auto;
    transition: all 0.3s ease;
}nav {
    margin-top: 10px;
}nav a {
    color: #F9FAFB;
    margin: 0 15px;
    font-size: 1.1em;
}/* 内容容器：放宽限制以支持更大视频框 */
.content {
    max-width: 1000px; /* 增加到 1000px 以匹配视频框 */
    margin: 0 auto;
    padding: 0 20px;
}/* 分割元素 */
.divider {
    width: 100%;
    height: 20px;
    background: linear-gradient(to bottom, rgba(15, 23, 42, 0), rgba(15, 23, 42, 1), rgba(15, 23, 42, 0));
    margin: 0;
}/* 通栏背景部分 */
section {
    padding: 50px 20px;
    min-height: 300px;
    background-size: cover;
    background-position: center;
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
    color: #F9FAFB;
    margin-bottom: 0;
}#hero {
    background-image: url('images/collection_of_electronic_books1.jpg');
    background-attachment: fixed;
    background-color: rgba(15, 23, 42, 0.9);
}#about {
    background-image: url('images/collection_of_books3.jpg');
    background-color: rgba(15, 23, 42, 0.9);
}#mission {
    background-image: url('images/collection_of_books_and_internet_against_a_bla_2.jpg');
    background-color: rgba(15, 23, 42, 0.9);
}#team {
    background-image: url('images/collection_of_books_and_internet_against_a_bla_5.jpg');
    background-color: rgba(15, 23, 42, 0.9);
}#contact {
    background-image: none;
    background-color: #0D1A3B;
}#privacy, #terms {
    background-image: url('images/collection_of_electronic_books1.jpg');
    background-color: rgba(15, 23, 42, 0.9);
}/* 下载页面样式 */
.download-section {
    background-image: none;
    background-color: #0F172A;
    padding: 50px 20px;
    min-height: auto; /* 避免高度限制 */
    overflow: visible; /* 防止裁剪 */
}/* YouTube 播放列表容器 */
.youtube-container {
    position: relative;
    width: 100%;
    padding-bottom: 56.25%; /* 16:9 宽高比 */
    height: 0;
    overflow: hidden;
    max-width: 1000px; /* 增大尺寸 */
    margin: 20px auto;
    background: #000;
}.youtube-container iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100% !important;
    height: 100% !important;
    border: none;
    display: block;
}/* 移除 .youtube-playlist iframe 样式以避免冲突 */
.youtube-playlist {
    margin: 20px 0;
    text-align: center;
}/* 其他样式 */
.book-image {
    max-width: 300px;
    height: auto;
    margin: 20px 0;
    border-radius: 5px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.3);
}.book-info {
    margin: 20px 0;
}.book-info p {
    line-height: 1.6;
}.book-info a.hashtag {
    margin: 0 5px;
    font-size: 0.95em;
}.download-links {
    margin: 20px 0;
    width: 100%;
}.download-links ul {
    list-style: none;
    padding: 0;
}.download-links li {
    display: flex;
    align-items: center;
    margin: 10px 0;
    padding: 10px;
    background-color: #1E3A8A;
    border-radius: 5px;
}.file-icon {
    width: 24px;
    height: 24px;
    margin-right: 10px;
}.download-button {
    background-color: #60A5FA;
    padding: 8px 16px;
    border-radius: 5px;
    color: #F9FAFB;
    font-size: 1em;
    transition: background-color 0.3s ease;
}.download-button:hover {
    background-color: #1E3A8A;
}.platforms {
    margin-left: 10px;
    font-size: 0.9em;
    color: #93C5FD;
}.series-image img {
    max-width: 600px;
    height: auto;
    margin: 20px 0;
    border-radius: 5px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.3);
}.twitter-tweet p, .twitter-tweet a:not(.twitter-video-player) {
    display: none;
}.social-share {
    margin: 20px 0;
}.share-button {
    background-color: #60A5FA;
    padding: 10px 20px;
    border-radius: 5px;
    color: #F9FAFB;
    font-size: 1em;
    transition: background-color 0.3s ease;
}.share-button:hover {
    background-color: #1E3A8A;
}/* 为 h2 添加上方间距（约三行，48px） */
h1, h2 {
    font-family: 'Georgia', serif;
    color: #F9FAFB;
    max-width: 600px;
}h1 {
    margin-bottom: 24px; 
}h2 {
    margin-top: 48px; /* 增加约三行间距（1.6em × 3 ≈ 48px） */
    margin-bottom: 24px; 
}p {
    max-width: 600px;
    line-height: 1.6;
}.cta-button {
    background-color: #60A5FA;
    padding: 10px 20px;
    border-radius: 5px;
    font-size: 1.1em;
}.cta-button:hover {
    background-color: #1E3A8A;
}form {
    max-width: 500px;
    display: flex;
    flex-direction: column;
    gap: 10px;
}input, textarea {
    padding: 10px;
    border: none;
    border-radius: 5px;
    background-color: #DBEAFE;
    color: #1E3A8A;
}button {
    background-color: #60A5FA;
    color: #F9FAFB;
    padding: 10px;
    border: none;
    border-radius: 5px;
    cursor: pointer;
}button:hover {
    background-color: #1E3A8A;
}footer {
    background-color: #0F172A;
    color: #F9FAFB;
    padding: 20px;
    text-align: center;
}footer a {
    margin: 0 10px;
}/* 响应式设计 */
@media (max-width: 768px) {
    header img {
        max-width: 120px;
    }
    nav a {
        font-size: 0.9em;
        margin: 0 10px;
    }
    section {
        padding: 30px 15px;
        min-height: 200px;
    }
    h1 {
        font-size: 1.8em;
    }
    h2 {
        font-size: 1.4em;
        margin-top: 32px; /* 移动端减小间距，约两行 */
    }
    p {
        font-size: 0.9em;
    }
    .divider {
        height: 15px;
    }
    .cover-image {
        max-width: 250px;
    }
    .series-image img {
        max-width: 400px;
    }
    .content {
        max-width: 90%;
    }
    .youtube-container {
        max-width: 100%;
    }
}@media (max-width: 480px) {
    nav a {
        display: block;
        margin: 5px 0;
    }
    form {
        width: 90%;
    }
    header img {
        max-width: 100px;
    }
    .content {
        max-width: 95%;
    }
    .divider {
        height: 10px;
    }
    .download-links li {
        flex-direction: column;
        align-items: flex-start;
    }
    .file-icon {
        margin-bottom: 5px;
    }
    .platforms {
        margin-left: 0;
        margin-top: 5px;
    }
    .youtube-container {
        max-width: 100%;
    }
    h2 {
        margin-top: 24px; /* 小屏幕进一步减小间距，约1.5行 */
    }
}