:root {
            --primary: #4361ee;
            --primary-dark: #3a0ca3;
            --text: #2b2d42;
            --text-light: #6c757d;
            --bg: #f8f9fa;
            --card-bg: #ffffff;
            --border: rgba(0, 0, 0, 0.08);
            --tutorial-bg: #f5f7ff;
            --success: #27ae60;
            --warning: #f39c12;
            --danger: #e74c3c;
        }
        
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: "PingFang SC", "Helvetica Neue", Arial, sans-serif;
        }
        
        body {
            background-color: var(--bg);
            color: var(--text);
            line-height: 1.5;
            padding: 16px;
        }
        
        .container {
            max-width: 800px;
            margin: 0 auto;
        }
        
        header {
            text-align: center;
            margin-bottom: 24px;
            padding: 20px;
            background: var(--card-bg);
            border-radius: 12px;
            box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
            border: 1px solid var(--border);
        }
        
        header h1 {
            font-size: 24px;
            font-weight: 600;
            margin-bottom: 8px;
            color: var(--primary);
        }
        
        header p {
            font-size: 14px;
            color: var(--text-light);
            margin-bottom: 4px;
        }
        
        .time-display {
            font-size: 14px;
            color: var(--text-light);
            margin: 8px 0;
            text-align: center;
        }
        
        .time-display span {
            font-weight: 600;
            color: var(--primary);
        }
        
        .upload-section {
            background: var(--card-bg);
            border-radius: 12px;
            padding: 24px;
            box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
            border: 1px solid var(--border);
            margin-bottom: 24px;
        }
        
        .upload-section h2 {
            font-size: 18px;
            font-weight: 600;
            color: var(--primary);
            margin-bottom: 20px;
            padding-bottom: 10px;
            border-bottom: 2px solid var(--primary);
        }
        
        .form-group {
            margin-bottom: 18px;
        }
        
        label {
            display: block;
            margin-bottom: 6px;
            font-weight: 600;
            color: var(--text);
            font-size: 14px;
        }
        
        input[type="text"],
        input[type="file"],
        textarea {
            width: 100%;
            padding: 12px 16px;
            border: 1px solid var(--border);
            border-radius: 8px;
            font-size: 14px;
            transition: all 0.2s;
            background: var(--bg);
        }
        
        input:focus,
        textarea:focus {
            outline: none;
            border-color: var(--primary);
            box-shadow: 0 0 0 3px rgba(67, 97, 238, 0.1);
        }
        
        .upload-btn-container {
            text-align: center;
            margin-top: 24px;
        }
        
        .upload-btn {
            background: var(--primary);
            color: white;
            padding: 14px 32px;
            border: none;
            border-radius: 8px;
            cursor: pointer;
            font-size: 16px;
            font-weight: 600;
            transition: all 0.3s;
            display: inline-flex;
            align-items: center;
            justify-content: center;
            gap: 8px;
            min-width: 160px;
            box-shadow: 0 4px 12px rgba(67, 97, 238, 0.3);
            position: relative;
            overflow: hidden;
        }
        
        .upload-btn:hover {
            background: var(--primary-dark);
            transform: translateY(-2px);
            box-shadow: 0 6px 16px rgba(67, 97, 238, 0.4);
        }
        
        .upload-btn:active {
            transform: translateY(0);
            box-shadow: 0 2px 8px rgba(67, 97, 238, 0.3);
        }
        
        .upload-btn::before {
            content: "";
            position: absolute;
            top: 0;
            left: -100%;
            width: 100%;
            height: 100%;
            background: linear-gradient(90deg, transparent, rgba(255,255,255,0.3), transparent);
            transition: left 0.5s;
        }
        
        .upload-btn:hover::before {
            left: 100%;
        }
        
        .upload-icon {
            font-size: 18px;
        }
        
        .submissions-list h2 {
            font-size: 18px;
            font-weight: 600;
            color: var(--primary);
            margin-bottom: 16px;
            padding-bottom: 10px;
            border-bottom: 2px solid var(--primary);
        }
        
        .no-submissions {
            text-align: center;
            padding: 40px;
            color: var(--text-light);
            font-style: italic;
            background: var(--card-bg);
            border-radius: 8px;
            border: 1px solid var(--border);
        }
        
        .submissions-container {
            display: flex;
            flex-direction: column;
            gap: 12px;
        }
        
        .submission-item {
            background: var(--card-bg);
            border-radius: 12px;
            box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
            border: 1px solid var(--border);
            overflow: hidden;
            transition: all 0.3s;
        }
        
        .submission-item:hover {
            transform: translateY(-2px);
            box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
        }
        
        .submission-header {
            padding: 18px;
            cursor: pointer;
            transition: all 0.3s;
            display: flex;
            justify-content: space-between;
            align-items: center;
            position: relative;
            gap: 16px;
        }
        
        .submission-header:hover {
            background: var(--tutorial-bg);
        }
        
        .submission-main-info {
            display: flex;
            align-items: center;
            flex: 1;
            min-width: 0; /* 关键：允许flex子元素收缩 */
            gap: 12px;
        }
        
        .submission-title {
            display: flex;
            align-items: center;
            min-width: 0; /* 关键：允许文本截断 */
            flex: 1;
        }
        
        .submission-title h3 {
            color: var(--text);
            margin: 0;
            font-size: 16px;
            font-weight: 600;
            white-space: nowrap;
            overflow: hidden;
            text-overflow: ellipsis;
            max-width: 180px; /* 限制最大宽度 */
        }
        
        .status-badge {
            padding: 5px 10px;
            border-radius: 20px;
            font-size: 11px;
            font-weight: bold;
            text-transform: uppercase;
            white-space: nowrap;
            flex-shrink: 0; /* 防止状态标签被挤压 */
        }
        
        .status-pending {
            background: #fff3cd;
            color: #856404;
        }
        
        .status-approved {
            background: #d4edda;
            color: #155724;
        }
        
        .status-rejected {
            background: #f8d7da;
            color: #721c24;
        }
        
        .submission-meta {
            display: flex;
            align-items: center;
            gap: 16px;
            font-size: 13px;
            color: var(--text-light);
            flex-shrink: 0; /* 防止元数据被挤压 */
        }
        
        .submission-meta span {
            white-space: nowrap;
            overflow: hidden;
            text-overflow: ellipsis;
            max-width: 120px; /* 限制元数据最大宽度 */
        }
        
        .expand-btn {
            width: 32px;
            height: 32px;
            border-radius: 50%;
            background: var(--primary);
            color: white;
            display: flex;
            align-items: center;
            justify-content: center;
            font-weight: bold;
            transition: all 0.3s;
            border: none;
            cursor: pointer;
            flex-shrink: 0; /* 防止按钮被挤压 */
        }
        
        .expand-btn:hover {
            background: var(--primary-dark);
            transform: scale(1.1);
        }
        
        .submission-item.active .expand-btn {
            transform: rotate(180deg);
            background: var(--primary-dark);
        }
        
        .submission-content {
            max-height: 0;
            overflow: hidden;
            transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
            background: var(--tutorial-bg);
        }
        
        .submission-item.active .submission-content {
            max-height: 500px;
        }
        
        .submission-details {
            padding: 20px;
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
            gap: 16px;
        }
        
        .submission-details p {
            margin: 0;
            color: var(--text);
            font-size: 14px;
            line-height: 1.4;
        }
        
        .submission-details strong {
            color: var(--text-light);
            font-weight: 600;
        }
        
        .rejection-reason {
            grid-column: 1 / -1;
            background: #f8f9fa;
            border-left: 4px solid var(--danger);
            padding: 12px;
            margin-top: 8px;
            border-radius: 0 4px 4px 0;
            font-size: 13px;
            line-height: 1.4;
        }
        
        .ip-display {
            font-size: 14px;
            color: var(--text-light);
            text-align: center;
            margin-top: 8px;
        }
        
        .ip-display span {
            font-weight: 600;
            color: var(--primary);
        }
        
        /* 长文本处理工具提示 */
        .tooltip {
            position: relative;
        }
        
        .tooltip:hover::after {
            content: attr(data-tooltip);
            position: absolute;
            bottom: 100%;
            left: 50%;
            transform: translateX(-50%);
            background: rgba(0, 0, 0, 0.8);
            color: white;
            padding: 8px 12px;
            border-radius: 4px;
            font-size: 12px;
            white-space: nowrap;
            z-index: 1000;
            margin-bottom: 5px;
        }
        
        @media (max-width: 768px) {
            .container {
                padding: 10px;
            }
            
            .submission-header {
                padding: 16px;
                flex-direction: column;
                align-items: flex-start;
                gap: 12px;
            }
            
            .submission-main-info {
                width: 100%;
                justify-content: space-between;
            }
            
            .submission-title h3 {
                max-width: 150px; /* 移动端更小的最大宽度 */
            }
            
            .submission-meta {
                width: 100%;
                justify-content: space-between;
                margin: 8px 0 0 0;
                padding-top: 8px;
                border-top: 1px solid var(--border);
            }
            
            .submission-meta span {
                max-width: 100px; /* 移动端更小的最大宽度 */
            }
            
            .expand-btn {
                position: absolute;
                right: 16px;
                top: 50%;
                transform: translateY(-50%);
            }
            
            .submission-details {
                grid-template-columns: 1fr;
                padding: 16px;
            }
        }
        
        @media (max-width: 480px) {
            .upload-section,
            .submission-header {
                padding: 14px;
            }
            
            input[type="text"],
            input[type="file"],
            textarea,
            .btn {
                font-size: 14px;
            }
            
            .upload-btn {
                padding: 12px 24px;
                font-size: 15px;
                min-width: 140px;
            }
            
            .submission-title h3 {
                max-width: 120px; /* 超小屏幕更小的最大宽度 */
            }
            
            .submission-meta {
                flex-direction: column;
                gap: 4px;
                align-items: flex-start;
            }
            
            .submission-meta span {
                max-width: none; /* 移动端垂直布局时不限制宽度 */
            }
        }