/* ===================================
   基础样式重置
   =================================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary: #4f46e5;
    --primary-hover: #4338ca;
    --success: #10b981;
    --danger: #ef4444;
    --warning: #f59e0b;
    --dark: #1f2937;
    --gray-50: #f9fafb;
    --gray-100: #f3f4f6;
    --gray-200: #e5e7eb;
    --gray-300: #d1d5db;
    --gray-400: #9ca3af;
    --gray-500: #6b7280;
    --gray-600: #4b5563;
    --gray-700: #374151;
    --gray-800: #1f2937;
    --gray-900: #111827;
    --radius: 8px;
    --shadow: 0 1px 3px rgba(0,0,0,0.1), 0 1px 2px rgba(0,0,0,0.06);
    --shadow-md: 0 4px 6px rgba(0,0,0,0.07), 0 2px 4px rgba(0,0,0,0.06);
    --shadow-lg: 0 10px 15px rgba(0,0,0,0.1), 0 4px 6px rgba(0,0,0,0.05);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans SC", sans-serif;
    color: var(--gray-700);
    background: var(--gray-50);
    line-height: 1.6;
}

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

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

/* ===================================
   按钮样式
   =================================== */
.btn {
    display: inline-block;
    padding: 10px 24px;
    border: none;
    border-radius: var(--radius);
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
    text-align: center;
}

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

.btn-primary:hover {
    background: var(--primary-hover);
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

.btn-secondary {
    background: var(--gray-200);
    color: var(--gray-700);
}

.btn-secondary:hover {
    background: var(--gray-300);
}

.btn-block {
    width: 100%;
}

.btn-sm {
    padding: 5px 12px;
    font-size: 12px;
    border-radius: 4px;
}

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

.btn-edit:hover {
    background: var(--primary-hover);
}

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

.btn-delete:hover {
    background: #dc2626;
}

/* ===================================
   表单样式
   =================================== */
.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    margin-bottom: 6px;
    font-weight: 500;
    color: var(--gray-700);
    font-size: 14px;
}

.required {
    color: var(--danger);
}

.form-group input[type="text"],
.form-group input[type="email"],
.form-group input[type="password"],
.form-group input[type="datetime-local"],
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 10px 14px;
    border: 1px solid var(--gray-300);
    border-radius: var(--radius);
    font-size: 14px;
    transition: border-color 0.2s, box-shadow 0.2s;
    background: #fff;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.1);
}

.form-group textarea {
    resize: vertical;
}

.form-hint {
    display: block;
    margin-top: 4px;
    font-size: 12px;
    color: var(--gray-400);
}

.form-actions {
    display: flex;
    gap: 12px;
    margin-top: 24px;
}

.form-card {
    background: #fff;
    border-radius: var(--radius);
    padding: 32px;
    box-shadow: var(--shadow);
}

.form-card-title {
    font-size: 18px;
    margin-bottom: 20px;
    padding-bottom: 12px;
    border-bottom: 1px solid var(--gray-200);
}

.form-row {
    display: flex;
    gap: 12px;
    align-items: center;
}

/* ===================================
   提示框样式
   =================================== */
.alert {
    padding: 12px 16px;
    border-radius: var(--radius);
    margin-bottom: 20px;
    font-size: 14px;
}

.alert-success {
    background: #d1fae5;
    color: #065f46;
    border: 1px solid #a7f3d0;
}

.alert-error {
    background: #fee2e2;
    color: #991b1b;
    border: 1px solid #fecaca;
}

/* ===================================
   登录页面
   =================================== */
.login-page {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
}

.login-container {
    width: 100%;
    max-width: 420px;
    padding: 20px;
}

.login-box {
    background: #fff;
    border-radius: 16px;
    padding: 48px 40px;
    box-shadow: var(--shadow-lg);
}

.login-box h1 {
    font-size: 28px;
    color: var(--gray-900);
    text-align: center;
    margin-bottom: 8px;
}

.login-subtitle {
    text-align: center;
    color: var(--gray-500);
    margin-bottom: 32px;
    font-size: 14px;
}

.login-box .form-group {
    margin-bottom: 20px;
}

.login-hint {
    text-align: center;
    margin-top: 24px;
    font-size: 13px;
    color: var(--gray-400);
}

/* ===================================
   后台布局
   =================================== */
.layout {
    display: flex;
    min-height: 100vh;
}

.sidebar {
    width: 240px;
    background: var(--gray-900);
    color: #fff;
    position: fixed;
    top: 0;
    left: 0;
    bottom: 0;
    overflow-y: auto;
}

.sidebar-header {
    padding: 24px 20px;
    border-bottom: 1px solid rgba(255,255,255,0.1);
}

.sidebar-header h2 {
    font-size: 20px;
    font-weight: 600;
}

.sidebar-nav {
    padding: 16px 0;
}

.nav-item {
    display: flex;
    align-items: center;
    padding: 12px 20px;
    color: rgba(255,255,255,0.7);
    transition: all 0.2s;
    border-left: 3px solid transparent;
}

.nav-item:hover {
    background: rgba(255,255,255,0.05);
    color: #fff;
}

.nav-item.active {
    background: rgba(79, 70, 229, 0.2);
    color: #fff;
    border-left-color: var(--primary);
}

.nav-icon {
    margin-right: 12px;
    font-size: 18px;
}

.nav-item.logout {
    margin-top: 16px;
    border-top: 1px solid rgba(255,255,255,0.1);
    color: var(--danger);
}

.main-content {
    flex: 1;
    margin-left: 240px;
    padding: 32px;
    background: var(--gray-50);
    min-height: 100vh;
}

.content-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 24px;
}

.content-header h1 {
    font-size: 24px;
    color: var(--gray-900);
}

/* ===================================
   排序栏样式
   =================================== */
.sort-bar {
    display: flex;
    align-items: center;
    gap: 10px;
    flex-wrap: wrap;
    padding: 12px 16px;
    background: var(--gray-100);
    border-radius: var(--radius);
    margin-bottom: 16px;
}

.sort-label {
    font-size: 14px;
    color: var(--gray-500);
    font-weight: 500;
}

.sort-tag {
    display: inline-block;
    padding: 6px 14px;
    background: #fff;
    color: var(--gray-600);
    border-radius: 6px;
    font-size: 13px;
    transition: all 0.2s;
    border: 1px solid var(--gray-200);
}

.sort-tag:hover {
    background: var(--primary);
    color: #fff;
    border-color: var(--primary);
}

.sort-tag.active {
    background: var(--primary);
    color: #fff;
    border-color: var(--primary);
}

/* ===================================
   表格样式
   =================================== */
.table-container {
    background: #fff;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    overflow: hidden;
}

.data-table {
    width: 100%;
    border-collapse: collapse;
}

.data-table thead {
    background: var(--gray-50);
}

.data-table th {
    padding: 14px 16px;
    text-align: left;
    font-weight: 600;
    font-size: 13px;
    color: var(--gray-500);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    border-bottom: 2px solid var(--gray-200);
}

.data-table td {
    padding: 14px 16px;
    border-bottom: 1px solid var(--gray-100);
    font-size: 14px;
}

.data-table tbody tr:hover {
    background: var(--gray-50);
}

.data-table tbody tr.row-urgent {
    background: #fef3c7;
    border-left: 3px solid var(--warning);
}

.data-table tbody tr.row-overdue {
    background: #fee2e2;
    border-left: 3px solid var(--danger);
}

.data-table .actions {
    white-space: nowrap;
}

.text-center {
    text-align: center !important;
}

.text-muted {
    color: var(--gray-400);
}

/* ===================================
   截止日期徽章
   =================================== */
.deadline-badge {
    display: inline-block;
    padding: 2px 8px;
    border-radius: 4px;
    font-size: 12px;
    font-weight: 500;
}

.deadline-normal {
    background: var(--gray-100);
    color: var(--gray-600);
}

.deadline-overdue {
    background: #fee2e2;
    color: #991b1b;
}

.urgent-badge {
    display: inline-block;
    padding: 2px 8px;
    background: var(--warning);
    color: #fff;
    border-radius: 4px;
    font-size: 11px;
    font-weight: 600;
    margin-left: 8px;
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.7; }
}

/* ===================================
   弹窗样式
   =================================== */
.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;
    backdrop-filter: blur(2px);
}

.modal {
    background: #fff;
    border-radius: 12px;
    width: 90%;
    max-width: 500px;
    box-shadow: 0 20px 60px rgba(0,0,0,0.3);
    animation: modalSlideIn 0.3s ease-out;
}

@keyframes modalSlideIn {
    from {
        transform: translateY(-30px);
        opacity: 0;
    }
    to {
        transform: translateY(0);
        opacity: 1;
    }
}

.modal-header {
    padding: 20px 24px;
    border-bottom: 1px solid var(--gray-200);
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: var(--gray-50);
}

.modal-header h3 {
    font-size: 18px;
    color: var(--gray-800);
    margin: 0;
}

.modal-close {
    background: none;
    border: none;
    font-size: 28px;
    cursor: pointer;
    color: var(--gray-400);
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 4px;
    transition: all 0.2s;
}

.modal-close:hover {
    color: var(--gray-600);
    background: var(--gray-200);
}

.modal-body {
    padding: 24px;
}

.modal-footer {
    padding: 16px 24px;
    border-top: 1px solid var(--gray-200);
    display: flex;
    gap: 12px;
    justify-content: flex-end;
    background: var(--gray-50);
}

/* ===================================
   前端 - 头部
   =================================== */
.frontend-page {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

.frontend-header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: #fff;
    padding: 48px 0;
    text-align: center;
}

.site-title {
    font-size: 36px;
    margin-bottom: 8px;
}

.site-title a {
    color: #fff;
}

.site-title a:hover {
    opacity: 0.9;
}

.site-desc {
    font-size: 16px;
    opacity: 0.8;
}

.frontend-footer {
    margin-top: auto;
    background: var(--gray-800);
    color: var(--gray-400);
    text-align: center;
    padding: 24px 0;
    font-size: 14px;
}

/* ===================================
   前端 - 搜索区域
   =================================== */
.search-section {
    background: #fff;
    padding: 32px 0;
    box-shadow: var(--shadow);
}

.search-form {
    margin-bottom: 20px;
}

.search-box {
    display: flex;
    gap: 0;
    max-width: 600px;
    margin: 0 auto;
}

.search-input {
    flex: 1;
    padding: 14px 20px;
    border: 2px solid var(--gray-200);
    border-right: none;
    border-radius: var(--radius) 0 0 var(--radius);
    font-size: 16px;
    transition: border-color 0.2s;
}

.search-input:focus {
    outline: none;
    border-color: var(--primary);
}

.search-btn {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 14px 28px;
    background: var(--primary);
    color: #fff;
    border: none;
    border-radius: 0 var(--radius) var(--radius) 0;
    font-size: 16px;
    font-weight: 500;
    cursor: pointer;
    transition: background 0.2s;
}

.search-btn:hover {
    background: var(--primary-hover);
}

.filter-bar {
    display: flex;
    align-items: center;
    gap: 10px;
    justify-content: center;
    flex-wrap: wrap;
}

.filter-label {
    font-size: 14px;
    color: var(--gray-500);
    font-weight: 500;
}

.filter-tag {
    display: inline-block;
    padding: 6px 16px;
    background: var(--gray-100);
    color: var(--gray-600);
    border-radius: 20px;
    font-size: 13px;
    transition: all 0.2s;
}

.filter-tag:hover {
    background: var(--primary);
    color: #fff;
}

.filter-tag.active {
    background: var(--primary);
    color: #fff;
}

/* ===================================
   前端 - 结果区域
   =================================== */
.results-section {
    flex: 1;
    padding: 40px 0;
}

.results-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 24px;
    padding-bottom: 16px;
    border-bottom: 1px solid var(--gray-200);
}

.results-header p {
    font-size: 16px;
    color: var(--gray-600);
}

.results-count {
    font-size: 14px;
    color: var(--gray-400);
    background: var(--gray-100);
    padding: 4px 12px;
    border-radius: 12px;
}

/* ====================================
   文章卡片 - 网格布局（每行4个）
   =================================== */
.articles-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 20px;
}

.article-card {
    background: #fff;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    transition: all 0.3s;
    border: 1px solid var(--gray-200);
    overflow: hidden;
    display: flex;
    flex-direction: column;
}

.article-card:hover {
    box-shadow: var(--shadow-lg);
    transform: translateY(-4px);
    border-color: var(--primary);
}

.article-card.row-urgent {
    border-color: var(--warning);
    box-shadow: 0 2px 8px rgba(245, 158, 11, 0.15);
}

.article-card.row-overdue {
    border-color: var(--danger);
    opacity: 0.85;
}

.article-card-header {
    padding: 16px 16px 8px;
}

.article-card-title {
    font-size: 15px;
    line-height: 1.5;
    margin: 0;
}

.article-card-title a {
    color: var(--gray-800);
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.article-card-title a:hover {
    color: var(--primary);
}

.article-card-meta {
    display: flex;
    gap: 6px;
    flex-wrap: wrap;
    padding: 0 16px 8px;
}

.meta-tag {
    display: inline-block;
    padding: 2px 8px;
    border-radius: 4px;
    font-size: 11px;
    font-weight: 500;
}

.meta-category {
    background: #eef2ff;
    color: var(--primary);
}

.meta-tag:not(.meta-category) {
    background: var(--gray-100);
    color: var(--gray-600);
}

.article-card-content {
    padding: 0 16px;
    color: var(--gray-600);
    font-size: 13px;
    line-height: 1.6;
    flex: 1;
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.article-card-footer {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 12px 16px;
    border-top: 1px solid var(--gray-100);
    margin-top: auto;
    flex-wrap: wrap;
}

.article-card-date {
    font-size: 12px;
    color: var(--gray-400);
}

.article-card-deadline {
    font-size: 12px;
    padding: 2px 8px;
    border-radius: 4px;
    font-weight: 500;
    background: var(--gray-100);
    color: var(--gray-600);
}

.badge-urgent {
    background: #fef3c7;
    color: #92400e;
    animation: pulse 2s infinite;
}

.badge-overdue {
    background: #fee2e2;
    color: #991b1b;
}

.urgent-text {
    font-weight: 600;
    margin-left: 4px;
}

.read-more {
    margin-left: auto;
    color: var(--primary);
    font-weight: 500;
    font-size: 12px;
}

.read-more:hover {
    color: var(--primary-hover);
}

/* ===================================
   文章详情
   =================================== */
.article-section {
    flex: 1;
    padding: 40px 0;
}

.article-detail {
    background: #fff;
    border-radius: var(--radius);
    padding: 40px;
    box-shadow: var(--shadow);
    border-left: 4px solid var(--gray-300);
}

.article-detail.row-urgent {
    border-left-color: var(--warning);
}

.article-detail.row-overdue {
    border-left-color: var(--danger);
}

.article-detail-header {
    margin-bottom: 24px;
    padding-bottom: 24px;
    border-bottom: 1px solid var(--gray-200);
}

.article-detail-title {
    font-size: 28px;
    color: var(--gray-900);
    line-height: 1.4;
    margin-bottom: 16px;
}

.article-detail-meta {
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
}

.article-tags-large {
    margin-bottom: 24px;
}

.article-content {
    font-size: 16px;
    line-height: 1.8;
    color: var(--gray-700);
    margin-bottom: 32px;
}

.article-detail-footer {
    padding-top: 24px;
    border-top: 1px solid var(--gray-200);
}

.back-btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 10px 20px;
    background: var(--gray-100);
    color: var(--gray-600);
    border-radius: var(--radius);
    font-size: 14px;
    transition: all 0.2s;
}

.back-btn:hover {
    background: var(--gray-200);
}

/* 上一篇/下一篇 */
.article-nav {
    display: flex;
    justify-content: space-between;
    margin-top: 32px;
    gap: 16px;
}

.nav-link {
    flex: 1;
    padding: 16px 20px;
    background: #fff;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    transition: all 0.2s;
}

.nav-link:hover {
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
}

.nav-link.prev {
    border-left: 3px solid var(--primary);
}

.nav-link.next {
    border-left: 3px solid var(--primary);
    text-align: right;
}

.nav-link.disabled {
    opacity: 0.5;
    cursor: default;
}

.nav-label {
    display: block;
    font-size: 12px;
    color: var(--gray-400);
    margin-bottom: 4px;
}

/* ===================================
   空状态
   =================================== */
.empty-state {
    text-align: center;
    padding: 60px 20px;
}

.empty-icon {
    font-size: 64px;
    margin-bottom: 16px;
}

.empty-state p {
    font-size: 16px;
    color: var(--gray-500);
}

.empty-hint {
    font-size: 14px;
    color: var(--gray-400);
    margin-top: 8px;
}

/* ===================================
   响应式
   =================================== */
@media (max-width: 1200px) {
    .articles-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}

@media (max-width: 900px) {
    .articles-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 768px) {
    .sidebar {
        width: 0;
        overflow: hidden;
    }
    
    .main-content {
        margin-left: 0;
        padding: 20px;
    }
    
    .content-header {
        flex-direction: column;
        gap: 12px;
        align-items: flex-start;
    }
    
    .data-table {
        font-size: 13px;
    }
    
    .data-table th,
    .data-table td {
        padding: 10px 8px;
    }
    
    .site-title {
        font-size: 28px;
    }
    
    .search-box {
        flex-direction: column;
    }
    
    .search-input {
        border-radius: var(--radius);
        border-bottom: none;
    }
    
    .search-btn {
        border-radius: var(--radius);
        justify-content: center;
    }
    
    .article-card {
        padding: 16px;
    }
    
    .article-detail {
        padding: 24px;
    }
    
    .article-detail-title {
        font-size: 22px;
    }
    
    .article-nav {
        flex-direction: column;
    }
    
    .form-card {
        padding: 20px;
    }
    
    .login-box {
        padding: 32px 24px;
    }
    
    .articles-grid {
        grid-template-columns: 1fr;
    }
}

/* ===================================
   导入相关样式
   =================================== */
.import-hint {
    margin-bottom: 24px;
    padding: 16px;
    background: var(--gray-50);
    border-radius: var(--radius);
}

.import-hint h4 {
    margin-bottom: 12px;
    color: var(--gray-700);
}

.format-table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 8px;
}

.format-table th,
.format-table td {
    padding: 8px 12px;
    border: 1px solid var(--gray-200);
    text-align: left;
    font-size: 13px;
}

.format-table th {
    background: var(--gray-100);
    font-weight: 600;
}

.import-steps {
    padding-left: 20px;
    color: var(--gray-600);
}

.import-steps li {
    margin-bottom: 8px;
    line-height: 1.6;
}

.header-actions {
    display: flex;
    gap: 12px;
    align-items: center;
}

/* ====================================
   分页样式
   =================================== */
.pagination {
    display: flex;
    align-items: center;
    gap: 12px;
    justify-content: center;
    padding: 20px 0;
    margin-top: 20px;
}

.pagination-btn {
    display: inline-block;
    padding: 8px 16px;
    background: #fff;
    color: var(--primary);
    border: 1px solid var(--primary);
    border-radius: var(--radius);
    font-size: 14px;
    transition: all 0.2s;
}

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

.pagination-btn.prev {
    border-right-color: transparent;
    border-radius: var(--radius) 0 0 var(--radius);
}

.pagination-btn.next {
    border-left-color: transparent;
    border-radius: 0 var(--radius) var(--radius) 0;
}

.pagination-info {
    font-size: 14px;
    color: var(--gray-600);
    padding: 0 12px;
}