:root {
    /* 核心品牌色 - 更加稳重的企业蓝 */
    --primary-color: #0066CC;
    --primary-hover: #0052a3;
    --secondary-color: #858796;
    --success-color: #1cc88a;
    --info-color: #36b9cc;
    --warning-color: #f6c23e;
    --danger-color: #e74a3b;
    
    /* 背景色 */
    --bg-body: #f4f6f9;
    --bg-sidebar: #ffffff;
    --bg-card: #ffffff;
    
    /* 边框和分割线 */
    --border-color: #e3e6f0;
    
    /* 文本颜色 */
    --text-primary: #2c3e50;
    --text-secondary: #5a5c69;
    --text-light: #b0b3b8;
    
    /* 尺寸变量 */
    --sidebar-width: 250px;
    --header-height: 60px;
    
    /* 阴影 */
    --shadow-sm: 0 0.125rem 0.25rem 0 rgba(58, 59, 69, 0.2);
    --shadow: 0 0.15rem 1.75rem 0 rgba(58, 59, 69, 0.15);
    
    /* 渐变 */
    --gradient-primary: linear-gradient(135deg, #0066CC 0%, #224abe 100%);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    background-color: var(--bg-body);
    color: var(--text-primary);
    font-size: 14px;
    line-height: 1.5;
    height: 100vh;
    overflow: hidden; /* 隐藏 body 滚动条，使用内部滚动 */
    display: flex;
    flex-direction: column;
}

/* =========================================
   通用组件
   ========================================= */
a {
    color: var(--primary-color);
    text-decoration: none;
    transition: color 0.2s;
}

a:hover {
    color: var(--primary-hover);
    text-decoration: none;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-weight: 500;
    text-align: center;
    vertical-align: middle;
    user-select: none;
    padding: 0.375rem 0.75rem;
    font-size: 0.9rem;
    line-height: 1.5;
    border-radius: 0.35rem;
    transition: all 0.2s;
    cursor: pointer;
    border: 1px solid transparent;
    gap: 0.5rem;
}

.btn-primary {
    color: #fff;
    background-color: var(--primary-color);
    border-color: var(--primary-color);
    box-shadow: 0 2px 4px rgba(0, 102, 204, 0.3);
}

.btn-primary:hover {
    background-color: var(--primary-hover);
    border-color: var(--primary-hover);
    transform: translateY(-1px);
}

.btn-danger {
    color: #fff;
    background-color: var(--danger-color);
    border-color: var(--danger-color);
}

.btn-danger:hover {
    background-color: #be2617;
}

.btn-success {
    color: #fff;
    background-color: var(--success-color);
    border-color: var(--success-color);
}

.btn-success:hover {
    background-color: #17a673;
    border-color: #17a673;
}

.btn-info {
    color: #fff;
    background-color: var(--info-color);
    border-color: var(--info-color);
}

.btn-info:hover {
    background-color: #2c9faf;
    border-color: #2c9faf;
}

.btn-warning {
    color: #fff;
    background-color: var(--warning-color);
    border-color: var(--warning-color);
}

.btn-warning:hover {
    background-color: #dda20a;
    border-color: #dda20a;
}

.btn-secondary {
    color: #fff;
    background-color: var(--secondary-color);
    border-color: var(--secondary-color);
}

.btn-secondary:hover {
    background-color: #717384;
    border-color: #717384;
}

.btn-light {
    color: #3a3b45;
    background-color: #f8f9fc;
    border-color: #d1d3e2;
}

.btn-light:hover {
    background-color: #eaecf4;
    border-color: #d1d3e2;
}

.btn-outline-primary {
    color: var(--primary-color);
    background-color: transparent;
    border-color: var(--primary-color);
}

.btn-outline-primary:hover {
    color: #fff;
    background-color: var(--primary-color);
}

.btn-outline-info {
    color: var(--info-color);
    background-color: transparent;
    border-color: var(--info-color);
}

.btn-outline-info:hover {
    color: #fff;
    background-color: var(--info-color);
}

.btn-outline-danger {
    color: var(--danger-color);
    background-color: transparent;
    border-color: var(--danger-color);
}

.btn-outline-danger:hover {
    color: #fff;
    background-color: var(--danger-color);
}

.btn-outline-secondary {
    color: var(--text-secondary);
    background-color: transparent;
    border-color: var(--border-color);
}

.btn-outline-secondary:hover {
    background-color: #eaecf4;
    color: var(--text-primary);
}

/* =========================================
   卡片与容器 (Card & Container)
   ========================================= */
.container-fluid {
    width: 100%;
    padding-right: 1.5rem;
    padding-left: 1.5rem;
    margin-right: auto;
    margin-left: auto;
}

.card {
    position: relative;
    display: flex;
    flex-direction: column;
    min-width: 0;
    word-wrap: break-word;
    background-color: #fff;
    background-clip: border-box;
    border: 1px solid #e3e6f0;
    border-radius: 0.5rem;
    box-shadow: 0 0.15rem 1.75rem 0 rgba(58, 59, 69, 0.1); /* 更柔和的阴影 */
    margin-bottom: 2rem; /* 增加卡片下间距 */
}

.card-header {
    padding: 1.25rem 1.5rem; /* 增加头部内边距 */
    margin-bottom: 0;
    background-color: #f8f9fc;
    border-bottom: 1px solid #e3e6f0;
    border-top-left-radius: calc(0.5rem - 1px);
    border-top-right-radius: calc(0.5rem - 1px);
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.card-title {
    margin-bottom: 0;
    color: var(--primary-color);
    font-weight: 700;
    font-size: 1.1rem;
}

.card-body {
    flex: 1 1 auto;
    padding: 2rem; /* 显著增加内容区内边距 */
}

/* =========================================
   表单优化 (Forms)
   ========================================= */
.form-group {
    margin-bottom: 1.5rem; /* 增加表单项之间的间距 */
}

.form-group label {
    display: inline-block;
    margin-bottom: 0.5rem;
    font-weight: 600;
    color: var(--text-primary);
}

.form-control {
    display: block;
    width: 100%;
    height: 3rem; /* 增加输入框高度 */
    padding: 0.75rem 1rem; /* 增加内边距 */
    font-size: 0.95rem;
    font-weight: 400;
    line-height: 1.5;
    color: #6e707e;
    background-color: #fff;
    background-clip: padding-box;
    border: 1px solid #d1d3e2;
    border-radius: 0.35rem;
    transition: border-color 0.15s ease-in-out, box-shadow 0.15s ease-in-out;
}

/* =========================================
   文件列表样式 (File List)
   ========================================= */
.file-list-container {
    flex: 1;
    display: flex;
    flex-direction: column;
    background: #fff;
    border-radius: 0.5rem;
    box-shadow: var(--shadow-sm);
    overflow: hidden;
    margin: 0 1.5rem 1.5rem 1.5rem;
    border: 1px solid var(--border-color);
}

.file-list-header {
    display: flex;
    align-items: center;
    padding: 1rem;
    background-color: #f8f9fc;
    border-bottom: 1px solid var(--border-color);
    font-weight: 600;
    color: var(--text-secondary);
    font-size: 0.85rem;
}

.file-list-body {
    flex: 1;
    overflow-y: auto;
}

.file-item {
    display: flex;
    align-items: center;
    padding: 1rem;
    border-bottom: 1px solid var(--border-color);
    transition: background-color 0.2s;
}

.file-item:last-child {
    border-bottom: none;
}

.file-item:hover {
    background-color: #f8f9fc;
}

.file-icon {
    width: 40px;
    display: flex;
    justify-content: center;
    align-items: center;
    margin-right: 1rem;
    color: var(--secondary-color);
}

.file-name {
    flex: 1;
    font-weight: 500;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    margin-right: 1rem;
}

.file-name a {
    color: var(--text-primary);
}

.file-name a:hover {
    color: var(--primary-color);
}

.file-meta {
    width: 150px;
    color: var(--text-secondary);
    font-size: 0.85rem;
    text-align: right;
    margin-left: 1rem;
}

.file-actions-cell {
    width: 120px;
    display: flex;
    justify-content: flex-end;
    gap: 0.5rem;
    margin-left: 1rem;
    opacity: 0; /* 默认隐藏 */
    transition: opacity 0.2s;
}

.file-item:hover .file-actions-cell {
    opacity: 1; /* hover时显示 */
}

/* 移动端适配：始终显示操作按钮 */
@media (max-width: 768px) {
    .file-actions-cell {
        opacity: 1;
    }
    .file-meta {
        display: none; /* 移动端隐藏元数据 */
    }
}

.action-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 32px;
    height: 32px;
    border-radius: 50%;
    color: var(--text-secondary);
    transition: all 0.2s;
    background-color: transparent;
}

.action-btn:hover {
    color: var(--primary-color);
    background-color: #eaecf4;
}

.empty-state {
    padding: 4rem 2rem;
    text-align: center;
    color: var(--text-light);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
}

.empty-state svg {
    margin-bottom: 1rem;
    color: var(--border-color);
}

.empty-state p {
    font-size: 1.1rem;
    margin-bottom: 0;
}


/* =========================================
   工具类 (Utilities)
   ========================================= */
.mb-4 { margin-bottom: 1.5rem !important; }
.mt-4 { margin-top: 1.5rem !important; }
.p-4 { padding: 1.5rem !important; }
.gap-4 { gap: 1.5rem !important; }
.h-100 { height: 100% !important; }
.w-100 { width: 100% !important; }
.d-flex { display: flex !important; }
.align-items-center { align-items: center !important; }
.justify-content-between { justify-content: space-between !important; }

/* 修复行布局 */
.row {
    display: flex;
    flex-wrap: wrap;
    margin-right: -0.75rem;
    margin-left: -0.75rem;
}

/* 文件上传美化 */
input[type="file"] {
    padding: 0.5rem;
    height: auto;
    background: #f8f9fc;
}
input[type="file"]::-webkit-file-upload-button {
    background: var(--primary-color);
    color: #fff;
    border: none;
    padding: 0.5rem 1rem;
    border-radius: 0.25rem;
    cursor: pointer;
    margin-right: 1rem;
    font-weight: 500;
    transition: background 0.2s;
}
input[type="file"]::-webkit-file-upload-button:hover {
    background: var(--primary-hover);
}

.col-md-4, .col-md-6, .col-md-8, .col-12 {
    position: relative;
    width: 100%;
    padding-right: 0.75rem;
    padding-left: 0.75rem;
}

@media (min-width: 768px) {
    .col-md-4 { flex: 0 0 33.33333%; max-width: 33.33333%; }
    .col-md-6 { flex: 0 0 50%; max-width: 50%; }
    .col-md-8 { flex: 0 0 66.66667%; max-width: 66.66667%; }
}

.alert-danger {
    color: #721c24;
    background-color: #f8d7da;
    border-color: #f5c6cb;
}

.alert-success {
    color: #155724;
    background-color: #d4edda;
    border-color: #c3e6cb;
}

/* =========================================
   登录页布局 (Split Layout)
   ========================================= */
.login-page {
    display: flex;
    width: 100vw;
    height: 100vh;
    background-color: #fff;
    overflow: hidden;
}

.login-left {
    flex: 0 0 40%; /* 占比 40% */
    background: var(--gradient-primary);
    /* 移除可能加载失败的 Unsplash 图片，使用纯粹的渐变和图案 */
    background-image: linear-gradient(135deg, rgba(0, 102, 204, 0.9) 0%, rgba(34, 74, 190, 0.9) 100%), url('data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIHdpZHRoPSI0MCIgaGVpZ2h0PSI0MCIgdmlld0JveD0iMCAwIDQwIDQwIj48ZyBmaWxsLXJ1bGU9ImV2ZW5vZGQiPjxwYXRoIGQ9Ik0wIDQwaDQwVjBIMHY0MHptMjAgMjB2MjBoMjBWMjBIMjB6TTAgMjBoMjBWMHgyMEgweiIgZmlsbD0iI2ZmZiIgZmlsbC1vcGFjaXR5PSIwLjA1Ii8+PC9nPjwvc3ZnPg==');
    position: relative;
    display: flex;
    flex-direction: column;
    justify-content: center;
    padding: 4rem;
    color: #fff;
}

.login-left-content {
    max-width: 500px;
    z-index: 2;
}

.login-left h1 {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 1.5rem;
}

.login-left p {
    font-size: 1.2rem;
    line-height: 1.6;
    opacity: 0.9;
}

.login-right {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 2rem;
    background-color: #fff;
}

.login-form-container {
    width: 100%;
    max-width: 400px;
}

.login-header {
    margin-bottom: 2rem;
}

.login-header h2 {
    font-size: 1.8rem;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.login-footer {
    margin-top: 2rem;
    text-align: center;
    font-size: 0.85rem;
    color: var(--text-light);
}

/* =========================================
   主界面布局 (Dashboard Layout)
   ========================================= */
.app-container {
    display: flex;
    flex: 1;
    height: 100%;
    overflow: hidden;
}

/* 侧边栏 */
.sidebar {
    width: var(--sidebar-width);
    background-color: var(--bg-sidebar);
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    z-index: 100;
}

.sidebar-header {
    height: var(--header-height);
    display: flex;
    align-items: center;
    padding: 0 1.5rem;
    border-bottom: 1px solid var(--border-color);
}

.brand {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--primary-color);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.sidebar-nav {
    flex: 1;
    padding: 1rem 0;
    overflow-y: auto;
}

.nav-item {
    display: block;
}

.nav-link {
    display: flex;
    align-items: center;
    padding: 0.75rem 1.5rem;
    color: var(--text-secondary);
    font-weight: 500;
    transition: all 0.2s;
    gap: 0.75rem;
}

.nav-link:hover, .nav-link.active {
    color: var(--primary-color);
    background-color: #f0f7ff;
    border-right: 3px solid var(--primary-color);
}

.nav-link svg {
    width: 20px;
    height: 20px;
    stroke-width: 2;
}

/* 主内容区 */
.main-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    background-color: var(--bg-body);
    overflow: hidden;
}

.top-bar {
    height: var(--header-height);
    background-color: #fff;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 1.5rem;
}

.breadcrumb {
    font-size: 1rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.user-menu {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.user-avatar {
    width: 32px;
    height: 32px;
    border-radius: 50%;
    background-color: var(--primary-color);
    color: #fff;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.9rem;
    font-weight: 600;
}

.content-wrapper {
    flex: 1;
    padding: 1.5rem;
    overflow-y: auto;
}

/* =========================================
   文件列表样式 (File Browser)
   ========================================= */
.file-toolbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
}

.file-actions {
    display: flex;
    gap: 0.75rem;
}

.search-box {
    position: relative;
    width: 250px;
}

.search-box input {
    padding-left: 2.25rem;
    border-radius: 20px;
}

.search-icon {
    position: absolute;
    left: 0.75rem;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-light);
    width: 16px;
    height: 16px;
}

/* 文件表格重构 */
.file-list-header {
    display: grid;
    grid-template-columns: 50px 2fr 1fr 1fr 100px;
    padding: 0.75rem 1rem;
    background-color: #fff;
    border-bottom: 1px solid var(--border-color);
    color: var(--text-secondary);
    font-size: 0.85rem;
    font-weight: 600;
    text-transform: uppercase;
    border-top-left-radius: 0.5rem;
    border-top-right-radius: 0.5rem;
}

.file-list-body {
    background-color: #fff;
    border-bottom-left-radius: 0.5rem;
    border-bottom-right-radius: 0.5rem;
    box-shadow: var(--shadow-sm);
}

.file-item {
    display: grid;
    grid-template-columns: 50px 2fr 1fr 1fr 100px;
    padding: 0.75rem 1rem;
    border-bottom: 1px solid var(--border-color);
    align-items: center;
    transition: background-color 0.15s;
    cursor: default;
}

.file-item:last-child {
    border-bottom: none;
}

.file-item:hover {
    background-color: #f8f9fc;
}

.file-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--secondary-color);
}

.file-icon.folder {
    color: #f6c23e; /* 文件夹黄色 */
}

.file-name {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-weight: 500;
    color: var(--text-primary);
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.file-name a {
    color: inherit;
    text-decoration: none;
}

.file-name a:hover {
    color: var(--primary-color);
}

.file-meta {
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.file-actions-cell {
    text-align: right;
    opacity: 0;
    transition: opacity 0.2s;
}

.file-item:hover .file-actions-cell {
    opacity: 1;
}

.action-btn {
    background: none;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    padding: 4px;
    border-radius: 4px;
}

.action-btn:hover {
    background-color: #eaecf4;
    color: var(--primary-color);
}

/* 模态框 (简单覆盖层) */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0,0,0,0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
}

.modal {
    background: #fff;
    padding: 2rem;
    border-radius: 0.5rem;
    width: 400px;
    box-shadow: var(--shadow);
}