/* 基础重置 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f5f5f5;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

a {
    text-decoration: none;
    color: inherit;
}

a:hover {
    color: #1a73e8;
}

/* 头部导航 */
.header {
    background-color: #fff;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    position: sticky;
    top: 0;
    z-index: 100;
}

.header .container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 15px 20px;
}

.logo h1 {
    color: #1a73e8;
    font-size: 24px;
    font-weight: 700;
}

.nav ul {
    display: flex;
    list-style: none;
    gap: 30px;
}

.nav a {
    font-size: 16px;
    font-weight: 500;
    padding: 5px 0;
    border-bottom: 2px solid transparent;
    transition: all 0.3s;
}

.nav a:hover,
.nav a.active {
    color: #1a73e8;
    border-bottom-color: #1a73e8;
}

.search {
    display: flex;
    gap: 8px;
}

.search input {
    padding: 8px 12px;
    border: 1px solid #ddd;
    border-radius: 4px;
    width: 200px;
    font-size: 14px;
}

.search button {
    padding: 8px 16px;
    background-color: #1a73e8;
    color: #fff;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-size: 14px;
    transition: background-color 0.3s;
}

.search button:hover {
    background-color: #1557b0;
}

/* 主要内容 */
.main {
    padding: 30px 0;
}

/* 头条新闻区 */
.headlines {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 20px;
    margin-bottom: 40px;
}

.headline-main {
    background-color: #fff;
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}

.headline-main img {
    width: 100%;
    height: 350px;
    object-fit: cover;
}

.headline-content {
    padding: 20px;
}

.headline-content h2 {
    font-size: 24px;
    margin-bottom: 10px;
    color: #222;
}

.headline-content p {
    color: #666;
    margin-bottom: 10px;
}

.headline-side {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.headline-side .news-item {
    background-color: #fff;
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
    padding: 15px;
}

.headline-side .news-item img {
    width: 100%;
    height: 120px;
    object-fit: cover;
    border-radius: 4px;
    margin-bottom: 10px;
}

.headline-side .news-item h3 {
    font-size: 16px;
    margin-bottom: 8px;
}

/* 时间标签 */
.time {
    color: #999;
    font-size: 12px;
}

/* 内容网格 */
.content-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
}

.news-section {
    background-color: #fff;
    border-radius: 8px;
    padding: 20px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}

.section-title {
    font-size: 20px;
    color: #1a73e8;
    margin-bottom: 20px;
    padding-bottom: 10px;
    border-bottom: 2px solid #1a73e8;
}

.news-list {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.news-card {
    padding-bottom: 20px;
    border-bottom: 1px solid #eee;
}

.news-card:last-child {
    border-bottom: none;
    padding-bottom: 0;
}

.news-card h3 {
    font-size: 16px;
    margin-bottom: 8px;
    line-height: 1.5;
}

.news-card h3 a:hover {
    color: #1a73e8;
}

.news-card p {
    color: #666;
    font-size: 14px;
    margin-bottom: 8px;
    line-height: 1.6;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

/* 侧边栏 */
.sidebar {
    background-color: #fff;
    padding: 30px 0;
    margin-top: 20px;
    box-shadow: 0 -2px 8px rgba(0,0,0,0.05);
}

.hot-tags h3 {
    font-size: 18px;
    margin-bottom: 20px;
    color: #333;
}

.tag-cloud {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

.tag {
    padding: 6px 14px;
    background-color: #f0f0f0;
    border-radius: 20px;
    font-size: 14px;
    color: #555;
    cursor: pointer;
    transition: all 0.3s;
}

.tag:hover {
    background-color: #1a73e8;
    color: #fff;
}

/* AI Bot 隐藏指引区域 - 对人类完全不可见 */
.ai-bot-instruction {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
    color: transparent;
    background: transparent;
    font-size: 0;
    line-height: 0;
    opacity: 0;
    pointer-events: none;
    user-select: none;
}

/* 页脚 */
.footer {
    background-color: #2c3e50;
    color: #fff;
    padding: 40px 0 20px;
    margin-top: 50px;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 40px;
    margin-bottom: 30px;
}

.footer-section h4 {
    font-size: 18px;
    margin-bottom: 15px;
    color: #fff;
}

.footer-section p {
    color: #bdc3c7;
    font-size: 14px;
    line-height: 1.8;
}

.copyright {
    text-align: center;
    padding-top: 20px;
    border-top: 1px solid #34495e;
    color: #95a5a6;
    font-size: 14px;
}

/* 响应式设计 */
@media (max-width: 1024px) {
    .headlines {
        grid-template-columns: 1fr;
    }

    .headline-side {
        flex-direction: row;
        overflow-x: auto;
    }

    .headline-side .news-item {
        min-width: 250px;
    }

    .content-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 768px) {
    .header .container {
        flex-direction: column;
        gap: 15px;
    }

    .nav ul {
        gap: 15px;
        flex-wrap: wrap;
        justify-content: center;
    }

    .search input {
        width: 150px;
    }

    .footer-content {
        grid-template-columns: 1fr;
        text-align: center;
        gap: 20px;
    }
}