* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
        }
        
        body {
            background: #e6f7ff; /* 浅蓝色背景 */
            color: #333;
            min-height: 100vh;
            padding: 20px;
            display: flex;
            flex-direction: column;
            align-items: center;
        }
        
        .container {
            width: 100%;
            max-width: 1200px;
            margin: 0 auto;
        }
        
        header {
            text-align: center;
            margin-bottom: 30px;
            color: #1a5276; /* 深蓝色文字 */
            padding: 40px 20px;
            border-radius: 12px;
            background: rgba(255, 255, 255, 0.8); /* 半透明白色背景 */
            backdrop-filter: blur(12px);
            box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
            width: 100%;
        }
        
        h1 {
            font-size: 2.8rem;
            margin-bottom: 10px;
            color: #2874a6; /* 蓝色标题 */
        }
        
        .description {
            font-size: 1.2rem;
            opacity: 0.9;
            max-width: 700px;
            margin: 0 auto;
            color: #3498db; /* 蓝色描述文字 */
        }
        
        .main-content {
            display: flex;
            gap: 25px;
            flex-wrap: wrap;
            width: 100%;
            margin-bottom: 40px;
        }
        
        .message-board {
            flex: 1;

        }
        
        .message-form {
            padding: 30px;
            background: #f0f8ff; /* 浅蓝色表单背景 */
            border-bottom: 1px solid #d6eaf8; /* 浅蓝色边框 */
        }
        
        .form-title {
            font-size: 1.5rem;
            margin-bottom: 25px;
            color: #2874a6; /* 蓝色标题 */
            display: flex;
            align-items: center;
            padding-bottom: 15px;
            border-bottom: 2px solid rgba(40, 116, 166, 0.2); /* 蓝色下划线 */
        }
        
        .form-title i {
            margin-right: 12px;
            background: #3498db; /* 蓝色图标背景 */
            color: white;
            width: 45px;
            height: 45px;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 1.3rem;
        }
        
        .input-group {
            margin-bottom: 20px;
        }
        
        label {
            display: block;
            margin-bottom: 8px;
            font-weight: 600;
            color: #2c3e50; /* 深蓝色标签 */
        }
        
        input, textarea {
            width: 100%;
            padding: 14px 18px;
            border: 2px solid #d6eaf8; /* 浅蓝色边框 */
            border-radius: 8px;
            font-size: 1.05rem;
            transition: all 0.3s;
            background: #f8fdff; /* 浅蓝色输入背景 */
        }
        
        input:focus, textarea:focus {
            outline: none;
            border-color: #3498db; /* 蓝色边框 */
            box-shadow: 0 0 0 4px rgba(52, 152, 219, 0.2);
        }
        
        textarea {
            min-height: 140px;
            resize: vertical;
            line-height: 1.7;
        }
        
        .btn {
            background: linear-gradient(to right, #3498db, #2980b9); /* 蓝色渐变按钮 */
            color: white;
            border: none;
            padding: 15px 25px;
            border-radius: 8px;
            cursor: pointer;
            font-size: 1.1rem;
            font-weight: 600;
            transition: all 0.3s;
            display: inline-flex;
            align-items: center;
        }
        
        .btn i {
            margin-right: 10px;
        }
        
        .btn:hover {
            transform: translateY(-3px);
            box-shadow: 0 12px 25px rgba(52, 152, 219, 0.4);
            background: linear-gradient(to right, #2980b9, #2575fc);
        }
        
        .captcha-container {
            display: flex;
            align-items: center;
            gap: 15px;
            margin-bottom: 25px;
        }
        
        .captcha-input {
            flex: 1;
        }
        
        .captcha-image {
            flex: 0 0 120px;
            height: 50px;
            background: #f0f8ff; /* 浅蓝色背景 */
            border-radius: 6px;
            display: flex;
            align-items: center;
            justify-content: center;
            overflow: hidden;
            cursor: pointer;
            box-shadow: 0 4px 10px rgba(0, 0, 0, 0.1);
            border: 1px solid #d6eaf8; /* 浅蓝色边框 */
        }
        
        .captcha-image img {
            width: 100%;
            height: 100%;
            object-fit: cover;
        }
        
        .captcha-refresh {
            flex: 0 0 45px;
            height: 45px;
            background: #3498db; /* 蓝色背景 */
            color: white;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            cursor: pointer;
            transition: all 0.3s;
            box-shadow: 0 5px 15px rgba(52, 152, 219, 0.4);
        }
        
        .captcha-refresh:hover {
            transform: rotate(90deg);
            background: #2980b9;
        }
        
        .messages-container {
            padding: 30px;
            max-height: 600px;
            overflow-y: auto;
            background: #f8fdff; /* 浅蓝色背景 */
        }
        
        .messages-header {
            display: flex;
            justify-content: space-between;
            align-items: center;
            margin-bottom: 25px;
            padding-bottom: 20px;
            border-bottom: 2px solid rgba(40, 116, 166, 0.1); /* 蓝色下划线 */
        }
        
        .messages-title {
            font-size: 1.5rem;
            color: #2874a6; /* 蓝色标题 */
            display: flex;
            align-items: center;
        }
        
        .messages-title i {
            margin-right: 12px;
            background: #3498db; /* 蓝色图标背景 */
            color: white;
            width: 45px;
            height: 45px;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 1.3rem;
        }
        
        .message-count {
            background: rgba(52, 152, 219, 0.1); /* 浅蓝色背景 */
            padding: 10px 20px;
            border-radius: 30px;
            font-weight: 600;
            color: #2874a6; /* 蓝色文字 */
            font-size: 1.1rem;
            display: flex;
            align-items: center;
        }
        
        .message-count i {
            margin-right: 8px;
        }
        
        .message-list {
            list-style: none;
        }
        
        .message-item {
            background: white;
            border-radius: 15px;
            padding: 25px;
            margin-bottom: 25px;
            box-shadow: 0 8px 20px rgba(0, 0, 0, 0.08);
            border-left: 5px solid #3498db; /* 蓝色左边框 */
            position: relative;
            overflow: hidden;
            transition: all 0.3s;
        }
        
        .message-item:hover {
            transform: translateY(-5px);
            box-shadow: 0 15px 30px rgba(0, 0, 0, 0.1);
        }
        
        .message-header {
            display: flex;
            justify-content: space-between;
            margin-bottom: 18px;
            align-items: center;
            flex-wrap: wrap;
            gap: 15px;
        }
        
        .message-author {
            font-weight: 700;
            color: #2874a6; /* 蓝色作者名 */
            font-size: 1.25rem;
            display: flex;
            align-items: center;
        }
        
        .message-author i {
            margin-right: 10px;
            color: #3498db; /* 蓝色图标 */
            font-size: 1.4rem;
        }
        
        .message-time {
            color: #7fb3d5; /* 浅蓝色时间 */
            font-size: 1rem;
            background: rgba(52, 152, 219, 0.05); /* 浅蓝色背景 */
            padding: 8px 15px;
            border-radius: 20px;
            font-weight: 500;
            display: flex;
            align-items: center;
        }
        
        .message-time i {
            margin-right: 8px;
            color: #3498db; /* 蓝色图标 */
        }
        
        .message-content {
            line-height: 1.8;
            color: #2c3e50; /* 深蓝色内容 */
            margin-bottom: 20px;
            font-size: 1.1rem;
            padding: 15px 0;
            border-top: 1px dashed rgba(52, 152, 219, 0.1); /* 浅蓝色虚线 */
            border-bottom: 1px dashed rgba(52, 152, 219, 0.1); /* 浅蓝色虚线 */
        }
        
        .message-actions {
            display: flex;
            justify-content: flex-end;
        }
        
        .delete-btn {
            background: linear-gradient(to right, #e74c3c, #c0392b); /* 红色渐变按钮 */
            color: white;
            border: none;
            padding: 12px 20px;
            border-radius: 8px;
            cursor: pointer;
            font-size: 1rem;
            display: flex;
            align-items: center;
            transition: all 0.3s;
            text-decoration: none;
            font-weight: 500;
        }
        
        .delete-btn i {
            margin-right: 8px;
        }
        
        .delete-btn:hover {
            transform: translateY(-3px);
            box-shadow: 0 8px 20px rgba(231, 76, 60, 0.4);
        }
        
        .empty-state {
            text-align: center;
            padding: 50px 20px;
            color: #7fb3d5; /* 浅蓝色文字 */
        }
        
        .empty-state i {
            font-size: 4rem;
            margin-bottom: 20px;
            color: #d6eaf8; /* 浅蓝色图标 */
        }
        
        .empty-state h3 {
            font-size: 1.8rem;
            margin-bottom: 15px;
            color: #3498db; /* 蓝色标题 */
        }
        
        .empty-state p {
            font-size: 1.15rem;
            margin-bottom: 25px;
            max-width: 500px;
            margin: 0 auto 25px;
            line-height: 1.7;
        }
        
        .users-panel {
            flex: 0 0 300px;
            background: white;
            border-radius: 12px;
            box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
            padding: 30px;
            max-height: 500px;
            position: relative;
            overflow: hidden;
        }
        
        .users-panel::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 5px;
            background: linear-gradient(to right, #3498db, #2874a6); /* 蓝色渐变 */
        }
        
        .users-title {
            font-size: 1.4rem;
            color: #2874a6; /* 蓝色标题 */
            margin-bottom: 25px;
            display: flex;
            align-items: center;
            padding-bottom: 15px;
            border-bottom: 2px solid rgba(40, 116, 166, 0.1); /* 蓝色下划线 */
        }
        
        .users-title i {
            margin-right: 15px;
            background: #3498db; /* 蓝色图标背景 */
            color: white;
            width: 45px;
            height: 45px;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 1.3rem;
        }
        
        .users-list {
            list-style: none;
        }
        
        .user-item {
            padding: 15px;
            border-bottom: 1px solid rgba(0, 0, 0, 0.05);
            display: flex;
            align-items: center;
            transition: all 0.3s;
            border-radius: 10px;
            margin-bottom: 12px;
            background: #f8fdff; /* 浅蓝色背景 */
            box-shadow: 0 4px 10px rgba(0, 0, 0, 0.05);
        }
        
        .user-item:hover {
            transform: translateX(5px);
            box-shadow: 0 8px 15px rgba(0, 0, 0, 0.1);
        }
        
        .user-avatar {
            width: 45px;
            height: 45px;
            border-radius: 50%;
            background: linear-gradient(to right, #3498db, #2874a6); /* 蓝色渐变 */
            color: white;
            display: flex;
            align-items: center;
            justify-content: center;
            margin-right: 15px;
            font-weight: bold;
            font-size: 1.25rem;
            box-shadow: 0 5px 15px rgba(52, 152, 219, 0.4);
        }
        
        .user-info {
            flex: 1;
        }
        
        .user-name {
            font-weight: 600;
            color: #2c3e50; /* 深蓝色名字 */
            font-size: 1.1rem;
            margin-bottom: 5px;
        }
        
        .user-last-active {
            font-size: 0.9rem;
            color: #7fb3d5; /* 浅蓝色时间 */
            display: flex;
            align-items: center;
        }
        
        .user-last-active i {
            margin-right: 5px;
            color: #3498db; /* 蓝色图标 */
        }
        
        .user-message-count {
            background: rgba(52, 152, 219, 0.1); /* 浅蓝色背景 */
            padding: 8px 15px;
            border-radius: 20px;
            font-size: 0.95rem;
            font-weight: 600;
            color: #2874a6; /* 蓝色文字 */
            display: flex;
            align-items: center;
        }
        
        .user-message-count i {
            margin-right: 8px;
        }
        
        .notification {
            padding: 18px 25px;
            border-radius: 12px;
            margin-bottom: 25px;
            display: flex;
            align-items: center;
            box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
            position: relative;
            overflow: hidden;
        }
        
        .notification::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            width: 5px;
            height: 100%;
        }
        
        .notification.success {
            background: rgba(46, 204, 113, 0.1); /* 浅绿色背景 */
            color: #27ae60; /* 绿色文字 */
            border-left: 5px solid #2ecc71; /* 绿色左边框 */
        }
        
        .notification.error {
            background: rgba(231, 76, 60, 0.1); /* 浅红色背景 */
            color: #c0392b; /* 红色文字 */
            border-left: 5px solid #e74c3c; /* 红色左边框 */
        }
        
        .notification i {
            margin-right: 15px;
            font-size: 1.8rem;
        }
        
        .notification-text {
            flex: 1;
        }
        
        .notification-title {
            font-weight: 600;
            margin-bottom: 5px;
            font-size: 1.2rem;
        }
        
        footer {
            text-align: center;
            color: #2874a6; /* 蓝色文字 */
            margin-top: 40px;
            padding: 25px;
            width: 100%;
            font-size: 1.1rem;
            background: rgba(52, 152, 219, 0.1); /* 浅蓝色背景 */
            border-radius: 12px;
            backdrop-filter: blur(10px);
        }
        
        footer p {
            margin-bottom: 10px;
        }
        
        .social-links {
            display: flex;
            justify-content: center;
            gap: 20px;
            margin-top: 15px;
        }
        
        .social-links a {
            color: #3498db; /* 蓝色图标 */
            font-size: 1.5rem;
            transition: all 0.3s;
        }
        
        .social-links a:hover {
            transform: translateY(-5px);
            color: #2874a6; /* 深蓝色图标 */
        }
        
        @media (max-width: 1000px) {
            .main-content {
                flex-direction: column;
            }
            
            .users-panel {
                width: 100%;
            }
        }
        
        @media (max-width: 700px) {
            .message-form, .messages-container {
                padding: 20px;
            }
            
            h1 {
                font-size: 2.2rem;
            }
            
            .btn {
                width: 100%;
                justify-content: center;
            }
            
            .message-header {
                flex-direction: column;
                align-items: flex-start;
                gap: 15px;
            }
            
            .message-time {
                align-self: flex-start;
            }
            
            .captcha-container {
                flex-direction: column;
                align-items: stretch;
            }
            
            .captcha-image {
                width: 100%;
            }
        }