/* ============ 全局样式 ============ */
:root {
    --primary: #2563eb;
    --primary-dark: #1d4ed8;
    --primary-light: #dbeafe;
    --success: #16a34a;
    --warning: #d97706;
    --danger: #dc2626;
    --gray-50: #f9fafb;
    --gray-100: #f3f4f6;
    --gray-200: #e5e7eb;
    --gray-300: #d1d5db;
    --gray-500: #6b7280;
    --gray-700: #374151;
    --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-lg: 0 10px 25px rgba(0,0,0,0.1);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
    background: var(--gray-50);
    color: var(--gray-900);
    line-height: 1.6;
    font-size: 14px;
}

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

/* ============ 登录/注册页 ============ */
.auth-container {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
    background: linear-gradient(135deg, #2563eb 0%, #1e40af 100%);
}

.auth-card {
    background: #fff;
    border-radius: 12px;
    box-shadow: var(--shadow-lg);
    width: 100%;
    max-width: 440px;
    padding: 40px;
}

.auth-card h1 {
    font-size: 24px;
    margin-bottom: 8px;
    text-align: center;
    color: var(--gray-900);
}

.auth-card .subtitle {
    text-align: center;
    color: var(--gray-500);
    margin-bottom: 28px;
}

.form-group {
    margin-bottom: 18px;
}

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

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 10px 12px;
    border: 1px solid var(--gray-300);
    border-radius: var(--radius);
    font-size: 14px;
    transition: border-color 0.2s;
    font-family: inherit;
}

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

.form-group textarea {
    resize: vertical;
    min-height: 100px;
}

.btn {
    display: inline-block;
    padding: 10px 20px;
    border: none;
    border-radius: var(--radius);
    font-size: 14px;
    cursor: pointer;
    transition: all 0.2s;
    font-weight: 500;
}

.btn-primary {
    background: var(--primary);
    color: #fff;
    width: 100%;
}
.btn-primary:hover { background: var(--primary-dark); }

.btn-secondary {
    background: var(--gray-200);
    color: var(--gray-700);
}
.btn-secondary:hover { background: var(--gray-300); }

.btn-danger {
    background: var(--danger);
    color: #fff;
}
.btn-danger:hover { background: #b91c1c; }

.btn-warning {
    background: #f59e0b;
    color: #fff;
}
.btn-warning:hover { background: #d97706; }

.btn-sm {
    padding: 6px 12px;
    font-size: 13px;
}

.auth-links {
    margin-top: 20px;
    text-align: center;
    color: var(--gray-500);
}

.alert {
    padding: 10px 14px;
    border-radius: var(--radius);
    margin-bottom: 16px;
    font-size: 14px;
    display: none;
}

.alert-success {
    background: #dcfce7;
    color: #166534;
    border: 1px solid #86efac;
}

.alert-error {
    background: #fee2e2;
    color: #991b1b;
    border: 1px solid #fca5a5;
}

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

.sidebar {
    width: 220px;
    background: #fff;
    border-right: 1px solid var(--gray-200);
    padding: 20px 0;
    flex-shrink: 0;
}

.sidebar .logo {
    padding: 0 20px 20px;
    font-size: 18px;
    font-weight: 700;
    color: var(--primary);
    border-bottom: 1px solid var(--gray-200);
    margin-bottom: 12px;
}

.sidebar .nav-item {
    display: block;
    padding: 12px 20px;
    color: var(--gray-700);
    font-weight: 500;
    transition: all 0.2s;
}

.sidebar .nav-item:hover {
    background: var(--gray-100);
    color: var(--primary);
    text-decoration: none;
}

.sidebar .nav-item.active {
    background: var(--primary-light);
    color: var(--primary);
    border-right: 3px solid var(--primary);
}

.main {
    flex: 1;
    padding: 24px;
    min-width: 0;
}

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

.topbar h2 {
    font-size: 20px;
}

.user-info {
    display: flex;
    align-items: center;
    gap: 12px;
}

.user-info .avatar {
    width: 36px;
    height: 36px;
    border-radius: 50%;
    background: var(--primary);
    color: #fff;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
}

/* ============ 卡片 ============ */
.card {
    background: #fff;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    padding: 20px;
    margin-bottom: 20px;
}

/* ============ 工具栏 ============ */
.toolbar {
    display: flex;
    align-items: center;
    gap: 12px;
    flex-wrap: wrap;
    margin-bottom: 20px;
}

.toolbar input,
.toolbar select {
    padding: 8px 12px;
    border: 1px solid var(--gray-300);
    border-radius: var(--radius);
    font-size: 14px;
}

.toolbar .spacer {
    flex: 1;
}

/* ============ 表格 ============ */
.table-wrap {
    overflow-x: auto;
}

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

table th, table td {
    padding: 12px 14px;
    text-align: left;
    border-bottom: 1px solid var(--gray-200);
}

table th {
    background: var(--gray-100);
    font-weight: 600;
    color: var(--gray-700);
    white-space: nowrap;
}

table tr:hover td {
    background: var(--gray-50);
}

.badge {
    display: inline-block;
    padding: 3px 10px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: 500;
}

.badge-success { background: #dcfce7; color: #166534; }
.badge-warning { background: #fef3c7; color: #92400e; }
.badge-danger  { background: #fee2e2; color: #991b1b; }
.badge-gray    { background: var(--gray-200); color: var(--gray-700); }
.badge-blue    { background: #dbeafe; color: #1e40af; }

/* ============ 模态框 ============ */
.modal-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,0.5);
    display: none;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    padding: 20px;
}

.modal-overlay.show {
    display: flex;
}

.modal {
    background: #fff;
    border-radius: 12px;
    width: 100%;
    max-width: 640px;
    max-height: 90vh;
    overflow-y: auto;
    padding: 28px;
    box-shadow: var(--shadow-lg);
}

.modal h3 {
    margin-bottom: 20px;
    font-size: 18px;
}

.modal .modal-actions {
    display: flex;
    gap: 12px;
    justify-content: flex-end;
    margin-top: 24px;
}

.modal-lg {
    max-width: 900px;
}

.modal-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 16px;
}

.modal-header h3 {
    margin: 0;
}

.modal-close {
    background: none;
    border: none;
    font-size: 26px;
    line-height: 1;
    cursor: pointer;
    color: var(--gray-500);
    padding: 0 4px;
}

.modal-close:hover {
    color: var(--gray-800);
}

.modal-footer {
    display: flex;
    gap: 12px;
    justify-content: flex-end;
    margin-top: 20px;
}

.result-box {
    margin-top: 16px;
    padding: 16px;
    background: #eff6ff;
    border: 1px solid #bfdbfe;
    border-radius: 8px;
    color: #1e40af;
}

.result-box code {
    background: #fff;
    padding: 2px 8px;
    border-radius: 4px;
    font-size: 16px;
    letter-spacing: 1px;
}

/* ============ 文件列表 ============ */
.file-list {
    margin-top: 12px;
}

.file-item {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 8px 12px;
    background: var(--gray-50);
    border-radius: 6px;
    margin-bottom: 6px;
}

.file-item .file-name {
    flex: 1;
    word-break: break-all;
}

.file-item .file-size {
    color: var(--gray-500);
    font-size: 12px;
    white-space: nowrap;
}

/* ============ 空状态 ============ */
.empty {
    text-align: center;
    padding: 60px 20px;
    color: var(--gray-500);
}

.empty .empty-icon {
    font-size: 48px;
    margin-bottom: 12px;
}

/* ============ 统计卡片 ============ */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 16px;
    margin-bottom: 24px;
}

.stat-card {
    background: #fff;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    padding: 20px;
}

.stat-card .stat-value {
    font-size: 28px;
    font-weight: 700;
    color: var(--primary);
}

.stat-card .stat-label {
    color: var(--gray-500);
    margin-top: 4px;
}

/* ============ 响应式 ============ */
@media (max-width: 768px) {
    .layout { flex-direction: column; }
    .sidebar { width: 100%; border-right: none; border-bottom: 1px solid var(--gray-200); }
    .sidebar .nav-item { display: inline-block; }
    .auth-card { padding: 24px; }
}