/* --- 基础与全局样式 --- */
:root {
    --primary-color: #3a7ca5;
    --dark-bg: #1a1a1a;
    --secondary-bg: #2a2a2a;
    --text-color: #e0e0e0;
    --text-secondary: #a0a0a0;
    --border-color: #444;
    --header-height: 81px;
    --nav-speed: 250ms; /* 定义动画速度 */
}

*, *::before, *::after { box-sizing: border-box; }

html { 
    scroll-behavior: smooth; 
    overflow-x: hidden; /* 防止水平滚动 */
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    line-height: 1.7;
    margin: 0;
    padding: 0;
    background-color: var(--dark-bg);
    color: var(--text-color);
    overflow-x: hidden; /* 防止水平滚动 */
    position: relative;
    width: 100%;
}

/* 当移动菜单打开时，禁止body滚动 */
.noscroll {
    overflow: hidden;
    position: fixed;
    width: 100%;
    height: 100%;
}

.container {
    width: 90%;
    max-width: 1100px;
    margin: auto;
    overflow: hidden;
    padding: 20px 0;
}

section {
    padding: 60px 0;
    border-bottom: 1px solid var(--border-color);
}

section[id] { scroll-margin-top: var(--header-height); }

.section-title {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 40px;
    color: #fff;
    font-weight: 300;
}

a {
    color: var(--primary-color);
    text-decoration: none;
    transition: color 0.3s ease;
}
a:hover { color: #fff; }

a:focus-visible, .btn:focus-visible {
    outline: 2px solid var(--primary-color);
    outline-offset: 3px;
    border-radius: 3px;
}

img { max-width: 100%; height: auto; display: block; }
.bg-alt { background-color: var(--secondary-bg); }

/* --- 头部与导航 --- */
header {
    background: rgba(26, 26, 26, 0.8);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px); /* 兼容 Safari */
    padding: 15px 0;
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.header-container { display: flex; justify-content: space-between; align-items: center; }
.logo-area { display: flex; align-items: center; gap: 15px; }
.logo-area .logo { height: 50px; }
.logo-area .wordmark { height: 35px; filter: invert(1); }

/* 桌面导航 */
.main-nav ul { padding: 0; margin: 0; list-style: none; display: flex; }
.main-nav li { padding: 0 15px; }
.main-nav a { color: var(--text-color); text-transform: uppercase; font-weight: bold; font-size: 14px; }

/* 移动端导航切换按钮 */
.nav-toggle {
    display: none; /* 默认隐藏 */
    background: none;
    border: none;
    cursor: pointer;
    padding: 10px;
    z-index: 1010; /* 确保在菜单之上 */
    position: relative;
    width: 44px; /* 优化触摸目标大小 */
    height: 44px;
}

.hamburger {
    display: block;
    position: relative;
    width: 24px;
    height: 2px;
    background: var(--text-color);
    transition: transform var(--nav-speed) ease-in-out;
}
.hamburger::before,
.hamburger::after {
    content: '';
    position: absolute;
    width: 100%;
    height: 2px;
    background: var(--text-color);
    left: 0;
    transition: transform var(--nav-speed) ease-in-out, top var(--nav-speed) ease-in-out;
}
.hamburger::before { top: -8px; }
.hamburger::after { top: 8px; }

/* 汉堡包变 "X" 的动画 */
.nav-toggle.is-active .hamburger {
    transform: rotate(45deg);
}
.nav-toggle.is-active .hamburger::before {
    top: 0;
    transform: rotate(90deg);
}
.nav-toggle.is-active .hamburger::after {
    top: 0;
    transform: rotate(90deg);
}

/* --- Hero 区域 --- */
.hero { text-align: center; padding: 80px 0; }
.hero .org-name-zh { font-size: 3rem; font-weight: bold; margin-bottom: 10px; color: #fff; }
.hero .org-name-en { font-size: 1.2rem; color: var(--text-secondary); margin-bottom: 30px; letter-spacing: 1px; }
.hero .slogan { font-family: 'Times New Roman', Times, serif; font-style: italic; font-size: 1.5rem; color: var(--primary-color); }

/* --- 网格与卡片 --- */
.grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 30px; }
.card { background: var(--secondary-bg); padding: 30px; border-radius: 8px; border: 1px solid var(--border-color); transition: transform 0.3s ease, box-shadow 0.3s ease; }
.card:hover { transform: translateY(-5px); box-shadow: 0 10px 20px rgba(0,0,0,0.2); }
.card h3 { margin-top: 0; font-size: 1.8rem; color: #fff; }
.card p { color: var(--text-secondary); }

/* --- 按钮 --- */
.btn { display: inline-block; background: var(--primary-color); color: #fff; padding: 12px 25px; border-radius: 5px; font-weight: bold; margin-top: 15px; transition: background-color 0.3s ease; }
.btn:hover { background: #4a90c2; color: #fff; }

/* --- 联系与赞助 --- */
#contact .contact-info, #sponsor .sponsor-info { text-align: center; font-size: 1.2rem; }

/* --- 页脚 --- */
footer { padding: 30px 0; text-align: center; color: var(--text-secondary); font-size: 0.9rem; border-top: 1px solid var(--border-color); }

/* --- 返回顶部按钮 --- */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    background-color: rgba(42, 42, 42, 0.7);
    border: 1px solid rgba(100, 100, 100, 0.5);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    color: #fff;
    width: 45px;
    height: 45px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 22px;
    font-weight: bold;
    text-decoration: none;
    z-index: 1001;
    opacity: 0;
    visibility: hidden;
    transform: translateY(100px);
    transition: opacity 0.3s ease, visibility 0.3s ease, transform 0.3s ease, background-color 0.3s ease, border-color 0.3s ease;
}
.back-to-top:hover {
    background-color: rgba(60, 60, 60, 0.8);
    border-color: rgba(150, 150, 150, 0.7);
    color: #fff;
}
.back-to-top.is-visible {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

/* --- 博客列表页专属样式 --- */
.page-header {
    text-align: center;
    padding: 40px 0;
    border-bottom: 1px solid var(--border-color);
    margin-bottom: 40px;
}
.page-header .page-title {
    font-size: 3rem;
    color: #fff;
    margin: 0;
}
.post-list-container {
    max-width: 900px;
    margin: 0 auto;
}
.post-item {
    padding: 30px 0;
    border-bottom: 1px solid var(--border-color);
    transition: background-color 0.3s ease;
}
.post-item:hover {
    background-color: rgba(255,255,255,0.03);
}
.post-item .post-title {
    margin: 0 0 10px 0;
}
.post-item .post-title a {
    font-size: 2rem;
    color: #fff;
    text-decoration: none;
}
.post-item .post-title a:hover {
    color: var(--primary-color);
}
.post-item .post-meta {
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin-bottom: 15px;
}
.post-item .post-excerpt {
    color: var(--text-color);
    line-height: 1.8;
}
.post-item .read-more {
    display: inline-block;
    margin-top: 15px;
    font-weight: bold;
}
.post-item .read-more:hover {
    text-decoration: underline;
}

/* --- 分页样式 --- */
.pagination {
    display: flex;
    justify-content: center;
    align-items: center;
    margin-top: 60px;
    gap: 10px;
}
.pagination a, .pagination span {
    color: var(--text-color);
    padding: 10px 15px;
    border: 1px solid var(--border-color);
    border-radius: 5px;
    text-decoration: none;
    transition: background-color 0.3s, border-color 0.3s;
}
.pagination a:hover {
    background-color: var(--primary-color);
    border-color: var(--primary-color);
    color: #fff;
}
.pagination .current {
    background-color: var(--primary-color);
    border-color: var(--primary-color);
    color: #fff;
}
.pagination .disabled {
    color: var(--text-secondary);
    border-color: #333;
    pointer-events: none;
}

/* --- 博客文章正文页专属样式 --- */
.post-container {
    max-width: 80ch; /* 限制内容宽度以提高可读性 */
    margin: 40px auto;
}
.post-header {
    text-align: center;
    margin-bottom: 40px;
    padding-bottom: 30px;
    border-bottom: 1px solid var(--border-color);
}
.post-header .post-title {
    font-size: 3rem;
    color: #fff;
    margin: 0 0 15px 0;
}
.post-header .post-meta {
    font-size: 0.9rem;
    color: var(--text-secondary);
}
.post-content {
    font-size: 1.1rem;
}
.post-content h2 {
    font-size: 2rem;
    color: #fff;
    margin-top: 60px;
    margin-bottom: 20px;
    padding-bottom: 10px;
    border-bottom: 1px solid var(--border-color);
}
.post-content p {
    margin-bottom: 1.5em;
}
.post-content blockquote {
    margin: 30px 0;
    padding: 20px;
    background: var(--secondary-bg);
    border-left: 4px solid var(--primary-color);
    color: var(--text-secondary);
    font-style: italic;
}
.post-content ul {
    padding-left: 20px;
}
.post-content li {
    margin-bottom: 0.8em;
}
.back-link-container {
    text-align: center;
    margin-top: 60px;
}

/* --- 响应式媒体查询 --- */
@media (max-width: 768px) {
    .section-title,
    .post-item .post-title a { font-size: 2rem; }
    .hero .org-name-zh { font-size: 2.2rem; }
    section { padding: 40px 0; }
    .post-header .post-title { font-size: 2.2rem; }
    .post-content { font-size: 1rem; }
    .post-content h2 { font-size: 1.8rem; }

    /* 移动端导航菜单样式 */
    .main-nav {
        position: fixed;
        top: 0;
        right: 0;
        width: 70%;
        max-width: 300px;
        height: 100vh;
        padding-top: var(--header-height);
        background: var(--dark-bg);
        transform: translateX(100%); /* 默认移出屏幕外 */
        transition: transform var(--nav-speed) ease-in-out;
        z-index: 1005;
        /* 确保初始状态不可见且不可交互 */
        visibility: hidden;
        opacity: 0;
        pointer-events: none;
        overflow-y: auto;
        -webkit-overflow-scrolling: touch;
    }
    .main-nav.is-open {
        transform: translateX(0); /* 激活时移入屏幕 */
        visibility: visible;
        opacity: 1;
        pointer-events: auto;
        box-shadow: -10px 0 30px rgba(0,0,0,0.3);
    }
    .main-nav ul {
        flex-direction: column;
        height: 100%;
    }
    .main-nav li {
        width: 100%;
        text-align: center;
    }
    .main-nav a {
        display: block;
        padding: 20px;
        font-size: 1.2rem;
        border-bottom: 1px solid var(--border-color);
    }
    .main-nav a:hover {
        background: var(--secondary-bg);
    }

    .nav-toggle {
        display: block; /* 在移动端显示汉堡包按钮 */
    }

    .back-to-top {
        bottom: 20px;
        right: 20px;
        width: 40px;
        height: 40px;
        font-size: 20px;
    }
    
    /* 博客文章页，移动端通常不显示完整导航 */
    /* .post-container header nav {
        display: none;
    } */
}