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

:root {
    --bg-primary: #ffffff;
    --bg-secondary: #f8f9fa;
    --bg-tertiary: #e9ecef;
    --text-primary: #212529;
    --text-secondary: #6c757d;
    --border-color: #dee2e6;
    --primary: #0d6efd;
    --primary-hover: #0b5ed7;
    --success: #198754;
    --success-hover: #157347;
    --danger: #dc3545;
    --danger-hover: #bb2d3b;
    --warning: #ffc107;
    --info: #0dcaf0;
    --shadow: 0 1px 3px rgba(0,0,0,0.1);
    --shadow-hover: 0 4px 6px rgba(0,0,0,0.15);
}

body.dark-mode {
    --bg-primary: #1a1a2e;
    --bg-secondary: #16213e;
    --bg-tertiary: #0f3460;
    --text-primary: #eaeaea;
    --text-secondary: #a0a0a0;
    --border-color: #2d4059;
    --shadow: 0 1px 3px rgba(0,0,0,0.3);
    --shadow-hover: 0 4px 6px rgba(0,0,0,0.4);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background-color: var(--bg-secondary);
    color: var(--text-primary);
    line-height: 1.6;
}

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

/* 头部样式 */
.header {
    background: var(--bg-primary);
    padding: 20px 30px;
    border-radius: 12px;
    margin-bottom: 30px;
    box-shadow: var(--shadow);
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 15px;
}

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

.nav {
    display: flex;
    gap: 15px;
    align-items: center;
}

.nav a {
    color: var(--text-secondary);
    text-decoration: none;
    padding: 8px 16px;
    border-radius: 6px;
    transition: all 0.3s;
}

.nav a:hover {
    color: var(--primary);
    background: var(--bg-tertiary);
}

/* 主题切换按钮 */
.theme-toggle {
    background: var(--bg-tertiary);
    border: none;
    padding: 10px;
    border-radius: 50%;
    cursor: pointer;
    color: var(--text-primary);
    transition: all 0.3s;
    font-size: 18px;
}

.theme-toggle:hover {
    background: var(--primary);
    color: white;
}

/* 内容区域 */
.content {
    background: var(--bg-primary);
    padding: 30px;
    border-radius: 12px;
    box-shadow: var(--shadow);
}

.content h2 {
    margin-bottom: 20px;
    color: var(--text-primary);
    font-size: 20px;
}

/* 按钮样式 */
.btn {
    display: inline-block;
    padding: 10px 20px;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    text-decoration: none;
    font-size: 14px;
    transition: all 0.3s;
    font-weight: 500;
}

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

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

.btn-success {
    background: var(--success);
    color: white;
}

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

.btn-danger {
    background: var(--danger);
    color: white;
}

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

.btn-warning {
    background: var(--warning);
    color: #333;
}

.btn-info {
    background: var(--info);
    color: white;
}

.btn-secondary {
    background: var(--text-secondary);
    color: white;
}

/* 警告框样式 */
.alert {
    padding: 15px 20px;
    border-radius: 8px;
    margin-bottom: 20px;
}

.alert-success {
    background: #d1e7dd;
    color: #0f5132;
    border: 1px solid #badbcc;
}

.alert-error {
    background: #f8d7da;
    color: #842029;
    border: 1px solid #f5c2c7;
}

.alert-info {
    background: #d1ecf1;
    color: #055160;
    border: 1px solid #bee5eb;
}

/* 上传区域 */
.upload-area {
    border: 2px dashed var(--border-color);
    border-radius: 12px;
    padding: 40px;
    text-align: center;
    cursor: pointer;
    margin-bottom: 30px;
    background: var(--bg-secondary);
    transition: all 0.3s;
}

.upload-area:hover,
.upload-area.dragover {
    border-color: var(--primary);
    background: var(--bg-tertiary);
}

.upload-area p {
    color: var(--text-secondary);
    font-size: 16px;
}

/* 文件列表 */
.file-list {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.file-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px;
    border: 1px solid var(--border-color);
    border-radius: 10px;
    background: var(--bg-secondary);
    transition: all 0.3s;
    flex-wrap: wrap;
    gap: 15px;
}

.file-item:hover {
    box-shadow: var(--shadow-hover);
    border-color: var(--primary);
}

.file-info {
    display: flex;
    gap: 20px;
    align-items: center;
    flex: 1;
    min-width: 200px;
}

.file-icon {
    font-size: 40px;
}

.file-details h4 {
    color: var(--text-primary);
    font-size: 16px;
}

.file-details p {
    color: var(--text-secondary);
    font-size: 13px;
    margin-top: 5px;
}

.file-actions {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
}

/* 分页 */
.pagination {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 10px;
    margin-top: 30px;
}

.pagination a,
.pagination span {
    padding: 10px 18px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    text-decoration: none;
    color: var(--text-primary);
    transition: all 0.3s;
}

.pagination a:hover {
    background: var(--primary);
    color: white;
    border-color: var(--primary);
}

.pagination .active {
    background: var(--primary);
    color: white;
    border-color: var(--primary);
}

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

.form-group label {
    display: block;
    margin-bottom: 8px;
    color: var(--text-primary);
    font-weight: 500;
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 12px 15px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    background: var(--bg-primary);
    color: var(--text-primary);
    font-size: 14px;
    transition: all 0.3s;
}

.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(13, 110, 253, 0.1);
}

/* 登录/注册表单 */
.auth-box {
    max-width: 450px;
    margin: 60px auto;
}

/* 响应式 */
@media (max-width: 768px) {
    .container {
        padding: 10px;
    }
    
    .header {
        flex-direction: column;
        text-align: center;
    }
    
    .nav {
        flex-wrap: wrap;
        justify-content: center;
    }
    
    .content {
        padding: 20px;
    }
    
    .file-item {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .file-actions {
        width: 100%;
    }
}