:root {
    /* 配色方案升级：更清新的科技蓝与柔和的粉紫色搭配 */
    --bg-gradient: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
    --primary: #2b99e7;
    --primary-hover: #1a7abf;
    --accent: #e8aaf4;
    --text-main: #2d3748;
    --text-muted: #718096;
    
    /* 玻璃拟态参数 */
    --glass-bg: rgba(255, 255, 255, 0.65);
    --glass-border: rgba(255, 255, 255, 0.8);
    --glass-shadow: 0 8px 32px 0 rgba(31, 38, 135, 0.07);
    --blur-amt: 12px;
    
    --radius: 16px;
    --container: 1100px;
    --font-main: 'Poppins', 'Noto Sans SC', sans-serif;
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-main);
    background-color: #e4e9f2;
    /* 三个巨大的彩色光斑叠加 */
    background-image: 
        radial-gradient(at 0% 0%, rgba(132, 250, 176, 0.4) 0px, transparent 50%),
        radial-gradient(at 100% 0%, rgba(143, 211, 244, 0.4) 0px, transparent 50%),
        radial-gradient(at 100% 100%, rgba(255, 215, 240, 0.4) 0px, transparent 50%),
        radial-gradient(at 0% 100%, rgba(215, 244, 255, 0.4) 0px, transparent 50%);
    background-attachment: fixed;
    
    color: var(--text-main);
    line-height: 1.6;
    overflow-x: hidden;
}

/* 樱花 canvas 层级 */
#canvas_sakura {
    z-index: 0;
}

/* 通用玻璃拟态类 */
.glass {
    background: var(--glass-bg);
    backdrop-filter: blur(var(--blur-amt));
    -webkit-backdrop-filter: blur(var(--blur-amt));
    border: 1px solid var(--glass-border);
    box-shadow: var(--glass-shadow);
}

.container {
    max-width: var(--container);
    margin: 0 auto;
    padding: 0 24px;
    position: relative;
    z-index: 1;
}

/* --- 导航栏 --- */
.site-header {
    position: sticky;
    top: 20px;
    margin: 0 auto;
    width: 90%;
    max-width: 1200px;
    border-radius: 50px; /* 丸子型导航栏 */
    z-index: 100;
    transition: all 0.3s ease;
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 12px 0;
}

.logo {
    font-weight: 800;
    font-size: 1.5rem;
    color: #0f172a;
    text-decoration: none;
    letter-spacing: -0.5px;
}

.logo span {
    color: var(--primary);
}

.site-nav a {
    color: var(--text-main);
    text-decoration: none;
    margin-left: 32px;
    font-weight: 500;
    font-size: 0.95rem;
    position: relative;
    transition: color 0.3s;
}

.site-nav a::after {
    content: '';
    position: absolute;
    width: 0;
    height: 2px;
    bottom: -4px;
    left: 0;
    background-color: var(--primary);
    transition: width 0.3s;
}

.site-nav a:hover {
    color: var(--primary);
}

.site-nav a:hover::after {
    width: 100%;
}

/* --- Hero 区域 --- */
.hero {
    min-height: 90vh; /* 占据大部分屏幕 */
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    padding-top: 60px;
}

.badge {
    display: inline-block;
    padding: 6px 16px;
    background: rgba(43, 153, 231, 0.1);
    color: var(--primary);
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 600;
    margin-bottom: 24px;
}

.hero h1 {
    font-size: 4rem;
    line-height: 1.1;
    margin-bottom: 24px;
    font-weight: 800;
    letter-spacing: -1px;
}

.hero h1 .highlight {
    background: linear-gradient(120deg, #84fab0 0%, #8fd3f4 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    position: relative;
    display: inline-block;
}

.hero .lead {
    font-size: 1.25rem;
    color: var(--text-muted);
    max-width: 600px;
    margin: 0 auto 40px;
}

.hero-cta {
    display: flex;
    gap: 20px;
    justify-content: center;
}

/* 按钮样式 */
.btn {
    padding: 12px 32px;
    border-radius: 12px;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s ease;
    display: inline-flex;
    align-items: center;
}

.btn.primary {
    background: var(--primary);
    color: white;
    box-shadow: 0 4px 14px rgba(43, 153, 231, 0.3);
}

.btn.primary:hover {
    background: var(--primary-hover);
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(43, 153, 231, 0.4);
}

.btn.ghost {
    background: transparent;
    color: var(--text-main);
    border: 1px solid rgba(0,0,0,0.1);
}

.btn.ghost:hover {
    border-color: var(--primary);
    color: var(--primary);
}

/* --- 侧边栏 --- */
#sidebar {
    position: fixed;
    right: 20px;
    top: 50%;
    transform: translateY(-50%);
    padding: 20px 10px;
    border-radius: 20px;
    z-index: 90;
    transition: all 0.5s cubic-bezier(0.68, -0.55, 0.27, 1.55); /* 弹性动画 */
    width: 160px; /* 展开宽度 */
    overflow: hidden;
}

#sidebar.sidebar-collapsed {
    width: 60px;
    padding: 20px 0;
}

#sidebar-toggle {
    width: 40px;
    height: 40px;
    background: white;
    border-radius: 50%;
    margin: 0 auto 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    box-shadow: 0 4px 10px rgba(0,0,0,0.1);
    color: var(--primary);
    font-weight: bold;
    font-size: 1.5rem;
    transition: transform 0.3s;
}

#sidebar-toggle:hover {
    transform: scale(1.1);
}

#department {
    display: flex;
    flex-direction: column;
    gap: 15px;
    opacity: 1;
    transition: opacity 0.3s;
}

#sidebar.sidebar-collapsed #department h2 {
    display: none;
}

#sidebar h2 {
    font-size: 0.8rem;
    text-align: center;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 2px;
    margin-bottom: 10px;
}

.dept-link {
    display: block;
    padding: 10px;
    text-align: center;
    text-decoration: none;
    color: var(--text-main);
    border-radius: 10px;
    font-size: 0.9rem;
    font-weight: 600;
    background: rgba(255,255,255,0.5);
    transition: all 0.2s;
    white-space: nowrap;
}

.dept-link:hover {
    background: var(--primary);
    color: white;
}

/* 收起时变成图标或竖排文字 */
#sidebar.sidebar-collapsed .dept-link {
    width: 40px;
    height: 40px;
    padding: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto;
    border-radius: 50%;
    font-size: 0.8rem;
}

/* --- 通用版块样式 --- */
.section {
    padding: 100px 0;
}

.section-header {
    text-align: center;
    margin-bottom: 60px;
}

.section-header h2 {
    font-size: 2.5rem;
    margin-bottom: 10px;
    color: #0f172a;
}

.section-header p {
    color: var(--text-muted);
    font-size: 1.1rem;
}

.grid {
    display: grid;
    gap: 30px;
}

.grid-3 { grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); }
.grid-4 { grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); }

/* --- 卡片设计 --- */
.card {
    padding: 40px 30px;
    border-radius: var(--radius);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    display: flex;
    flex-direction: column;
    align-items: flex-start;
}

.card:hover {
    transform: translateY(-10px);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.08);
    background: rgba(255,255,255, 0.8); /* 悬停时更不透明 */
}

.card-icon {
    font-size: 3rem;
    margin-bottom: 20px;
    background: linear-gradient(135deg, #e0f2fe 0%, #bae6fd 100%);
    width: 80px;
    height: 80px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 20px;
}

.card h3 {
    font-size: 1.4rem;
    margin-bottom: 12px;
}

/* --- 成员卡片 --- */
.member {
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
    padding: 30px;
    border-radius: var(--radius);
    transition: transform 0.3s;
}

.member:hover {
    transform: translateY(-5px);
}

.avatar-box {
    width: 100px;
    height: 100px;
    border-radius: 50%;
    padding: 5px; /* 边框间隙 */
    background: linear-gradient(45deg, var(--primary), var(--accent)); /* 渐变边框 */
    margin-bottom: 20px;
}

.avatar {
    width: 100%;
    height: 100%;
    background: #fff;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2rem;
    font-weight: bold;
    color: var(--primary);
}

.member figcaption strong {
    display: block;
    font-size: 1.1rem;
    margin-bottom: 4px;
}

.member figcaption span {
    font-size: 0.9rem;
    color: var(--primary);
    background: rgba(43, 153, 231, 0.1);
    padding: 4px 12px;
    border-radius: 20px;
}

/* --- 联系我们表单 --- */
.contact-wrapper {
    display: grid;
    grid-template-columns: 1fr 1.5fr;
    gap: 50px;
    padding: 60px;
    border-radius: 30px;
    align-items: center;
}

.contact-text h2 {
    font-size: 2rem;
    margin-bottom: 15px;
}

.contact-form {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.form-group {
    position: relative;
}

.form-group input {
    width: 100%;
    padding: 15px 20px;
    border: 2px solid rgba(0,0,0,0.05);
    border-radius: 12px;
    background: rgba(255,255,255,0.5);
    outline: none;
    transition: all 0.3s;
    font-size: 1rem;
}

.form-group input:focus {
    border-color: var(--primary);
    background: white;
    box-shadow: 0 0 0 4px rgba(43, 153, 231, 0.1);
}

/* 浮动标签效果 */
.form-group label {
    position: absolute;
    left: 20px;
    top: 50%;
    transform: translateY(-50%);
    color: #999;
    transition: all 0.3s;
    pointer-events: none;
}

.form-group input:focus + label,
.form-group input:not(:placeholder-shown) + label {
    top: -10px;
    left: 10px;
    font-size: 0.8rem;
    color: var(--primary);
    background: white;
    padding: 0 5px;
    border-radius: 4px;
}

/* --- 页脚 --- */
.site-footer {
    margin-top: 100px;
    padding: 50px 0;
    border-top: 1px solid rgba(255,255,255,0.3);
}

.footer-inner {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.footer-right a {
    color: var(--text-main);
    text-decoration: none;
    margin-left: 20px;
    transition: color 0.2s;
}

.footer-right a:hover {
    color: var(--primary);
}

/* --- 动画类 --- */
.scroll-hidden {
    opacity: 0;
    filter: blur(5px);
    transform: translateY(30px);
    transition: all 1s cubic-bezier(0.25, 0.46, 0.45, 0.94);
}

.scroll-hidden.show {
    opacity: 1;
    filter: blur(0);
    transform: translateY(0);
}

.delay-1 { transition-delay: 0.1s; }
.delay-2 { transition-delay: 0.2s; }
.delay-3 { transition-delay: 0.3s; }

/* --- 响应式 --- */
/* --- 移动端适配 (Responsive Design) --- */
/* --- 移动端适配 (Responsive Design) - 优化版 --- */
@media (max-width: 768px) {
    /* 1. 字体与间距调整 */
    .hero { padding-top: 100px; }
    .hero h1 { font-size: 2.2rem; }
    .section { padding: 60px 0; }
    
    /* 2. 导航栏适配 */
    .site-header {
        width: 95%;
        top: 10px;
        padding: 10px;
    }
    .site-nav { display: none; } 
    .logo { font-size: 1.2rem; }

    /* 3. 侧边栏重构：右下角悬浮按钮 (FAB) - 动效优化版 */
    #sidebar {
        /* 重置桌面端定位 */
        top: auto !important;
        transform: none !important;
        
        /* 定位：右下角 (稍微往上挪一点，避免被有些手机的底部横条遮挡) */
        bottom: 40px;
        right: 25px;
        
        /* 基础尺寸加大，更适合手指点击 */
        width: 60px;          
        height: 60px;         
        padding: 0;           
        
        /* 布局：按钮在下，菜单在上 */
        display: flex;
        flex-direction: column-reverse; 
        align-items: center;
        justify-content: center;
        overflow: hidden;    /* 隐藏溢出，配合高度动画 */
        
        /* 关键动画优化：时间延长至 0.6s，使用丝滑的减速曲线 */
        transition: all 0.6s cubic-bezier(0.25, 1, 0.5, 1);
        z-index: 999;
    }

    /* 收起状态：圆形大按钮 */
    #sidebar.sidebar-collapsed {
        height: 60px; /* 与基础高度一致 */
        width: 60px;
        background: var(--primary);
        border-radius: 50%;
        /* 增加更柔和的阴影 */
        box-shadow: 0 8px 20px rgba(43, 153, 231, 0.4);
    }
    
    #sidebar.sidebar-collapsed #sidebar-toggle {
        background: transparent;
        color: white;
        margin: 0;
    }

    /* 展开状态：长条胶囊 */
    #sidebar:not(.sidebar-collapsed) {
        height: 320px;        /* 设定一个足够容纳内容的高度，或者用 max-height */
        width: 70px;          /* 展开后稍微宽一点，更有呼吸感 */
        padding: 10px 0;
        border-radius: 35px;  /* 胶囊圆角 */
        background: rgba(255, 255, 255, 0.85); /* 提高不透明度，防止背景杂乱影响阅读 */
        backdrop-filter: blur(25px);
        -webkit-backdrop-filter: blur(25px);
        box-shadow: 0 10px 30px rgba(0,0,0,0.15);
    }

    /* 切换按钮 (+号) */
    #sidebar-toggle {
        width: 100%;
        height: 60px; /* 对应新的宽度 */
        margin: 0;
        background: transparent;
        box-shadow: none;
        font-size: 2rem; /* 图标变大 */
        display: flex;
        align-items: center;
        justify-content: center;
        /* 按钮旋转动画也同步变慢 */
        transition: transform 0.6s cubic-bezier(0.25, 1, 0.5, 1);
    }

    /* 部门链接容器 */
    #department {
        display: flex;
        flex-direction: column;
        gap: 18px; /* 增加间距 */
        margin-bottom: 15px;
        width: 100%;
        align-items: center;
        
        /* 内容出现的淡入动画 */
        opacity: 1;
        transition: opacity 0.4s ease 0.2s; /* 延迟 0.2s 显示，等背景先展开 */
    }

    /* 收起时隐藏内容 */
    #sidebar.sidebar-collapsed #department {
        display: none;
        opacity: 0;
        transition: none;
    }

    /* 部门链接按钮样式 */
    .dept-link {
        width: 50px;  /* 加大尺寸 */
        height: 50px;
        padding: 0;
        display: flex;
        align-items: center;
        justify-content: center;
        border-radius: 50%;
        font-size: 0.85rem; /* 字体微调 */
        background: white;
        color: var(--primary);
        box-shadow: 0 4px 10px rgba(0,0,0,0.05);
        transition: transform 0.2s;
    }
    
    .dept-link:active {
        transform: scale(0.9); /* 点击时的按压反馈 */
    }

    /* 隐藏 DEPT 标题 */
    #department h2 { display: none; }

    /* 4. 网格与布局适配 */
    .grid-3, .grid-4 { grid-template-columns: 1fr; }
    .contact-wrapper { grid-template-columns: 1fr; padding: 30px 20px; }
    .footer-inner { flex-direction: column; gap: 20px; text-align: center; }
    .footer-right a { margin: 0 10px; }
}