.chat-container {
                            height: 80vh;
                            display: flex;
                            flex-direction: column;
                        }

                        .chat-header {
                            background: white;
                            padding: 15px 20px;
                            border-bottom: 1px solid #e0e0e0;
                            display: flex;
                            justify-content: space-between;
                            align-items: center;
                        }

                        .chat-header-info {
                            display: flex;
                            align-items: center;
                            gap: 10px;
                        }

                        .chat-header-info img {
                            width: 40px;
                            height: 40px;
                            border-radius: 50%;
                        }

                        .chat-header-title h6 {
                            margin: 0;
                            font-weight: 600;
                        }

                        .chat-header-title small {
                            color: #666;
                            font-size: 12px;
                        }

                      .chat-messages {
    flex: 1;
    overflow-y: auto;
    padding: 20px;
    background: #fafafa;
    display: flex;
    /* Giữ nguyên chiều dọc nhưng đảo ngược vị trí bắt đầu */
    flex-direction: column-reverse; 
}

/* Thêm dòng này để các group tin nhắn không bị đảo ngược nội dung bên trong */
.chat-messages > * {
    flex-shrink: 0;
}

                        .message-group {
                            margin-bottom: 20px;
                        }
.message-date {
    display: flex;
    justify-content: center;
    margin: 20px 0 10px 0;
    width: 100%;
}

                        .message-date span {
                            background: #e3e3e3;
                            padding: 4px 12px;
                            border-radius: 12px;
                            font-size: 12px;
                            color: #666;
                        }

                        .message {
                            display: flex;
                            margin-bottom: 15px;
                            gap: 10px;
                        }

                        .message.sent {
                            flex-direction: row-reverse;
                        }

                        .message-avatar {
                            width: 36px;
                            height: 36px;
                            border-radius: 50%;
                            flex-shrink: 0;
                        }

                        .message-content {
                            max-width: 70%;
                        }

                        .message.sent .message-content {
                            display: flex;
                            flex-direction: column;
                            align-items: flex-end;
                        }

                        .message-bubble {
                            padding: 10px 15px;
                            border-radius: 18px;
                            margin-bottom: 4px;
                            word-wrap: break-word;
                        }

                        .message.received .message-bubble {
                            background: white;
                            border: 1px solid #e0e0e0;
                            border-top-left-radius: 4px;
                        }

                        .message.sent .message-bubble {
                            background: #e3f2fd;
                            border: 1px solid #bbdefb;
                            border-top-right-radius: 4px;
                        }

                        .message-time {
                            font-size: 11px;
                            color: #999;
                            padding: 0 5px;
                        }

                        .chat-input {
                            background: white;
                            border-top: 1px solid #e0e0e0;
                            padding: 15px 20px;
                        }

                        .chat-input-group {
                            display: flex;
                            gap: 10px;
                            align-items: center;
                        }

                        .chat-input-group input {
                            flex: 1;
                            border: 1px solid #e0e0e0;
                            border-radius: 24px;
                            padding: 10px 20px;
                            outline: none;
                        }

                        .chat-input-group input:focus {
                            border-color: #5e72e4;
                        }

                        .btn-send {
                            background: #5e72e4;
                            color: white;
                            border: none;
                            width: 40px;
                            height: 40px;
                            border-radius: 50%;
                            display: flex;
                            align-items: center;
                            justify-content: center;
                            cursor: pointer;
                        }

                        .btn-send:hover {
                            background: #4c63d2;
                        }

                        .user-list {
                            /* height: calc(100vh - 100px); */
                            background: white;
                            border-radius: 8px;
                            overflow: hidden;
                        }

                        .user-list-header {
                            padding: 15px 20px;
                            border-bottom: 1px solid #e0e0e0;
                        }

                        .user-list-header input {
                            border: 1px solid #e0e0e0;
                            border-radius: 20px;
                            padding: 8px 15px;
                            font-size: 14px;
                        }

                        #createGroupBtn {
                            border-radius: 50%;
                            width: 36px;
                            height: 36px;
                            padding: 0;
                            display: flex;
                            align-items: center;
                            justify-content: center;
                        }

                        .user-list-body {
                            overflow-y: auto;
                            height: calc(100% - 60px);
                        }

                        .user-item {
                            padding: 12px 20px;
                            display: flex;
                            align-items: center;
                            gap: 12px;
                            cursor: pointer;
                            border-bottom: 1px solid #f5f5f5;
                            transition: background 0.2s;
                        }

                        .user-item:hover {
                            background: #f8f9fa;
                        }

                        .user-item.active {
                            background: #e3f2fd;
                        }

                        .user-item img {
                            width: 40px;
                            height: 40px;
                            border-radius: 50%;
                        }

                        .user-item-info {
                            flex: 1;
                        }

                        .user-item-info h6 {
                            margin: 0;
                            font-size: 14px;
                            font-weight: 600;
                        }

                        .user-badge {
                            width: 20px;
                            height: 20px;
                            background: #f44336;
                            color: white;
                            border-radius: 50%;
                            font-size: 11px;
                            display: flex;
                            align-items: center;
                            justify-content: center;
                            font-weight: 600;
                        }

                        .dropdown-menu {
                            box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
                        }

                        .logo-brand {
                            width: 40px;
                            height: 40px;
                            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
                            border-radius: 50%;
                            display: flex;
                            align-items: center;
                            justify-content: center;
                            color: white;
                            font-weight: bold;
                            font-size: 16px;
                            flex-shrink: 0;
                        }
                        
                        .chat-room-item {
                            position: relative;
                        }
                        
                        .chat-room-item .badge {
                            font-size: 10px;
                            padding: 2px 6px;
                        }
                        
                        .user-list-body::-webkit-scrollbar {
                            width: 6px;
                        }
                        
                        .user-list-body::-webkit-scrollbar-track {
                            background: #f1f1f1;
                        }
                        
                        .user-list-body::-webkit-scrollbar-thumb {
                            background: #888;
                            border-radius: 3px;
                        }
                        
                        .user-list-body::-webkit-scrollbar-thumb:hover {
                            background: #555;
                        }
                        
                        .chat-messages::-webkit-scrollbar {
                            width: 6px;
                        }
                        
                        .chat-messages::-webkit-scrollbar-track {
                            background: #f1f1f1;
                        }
                        
                        .chat-messages::-webkit-scrollbar-thumb {
                            background: #888;
                            border-radius: 3px;
                        }
                        
                        .chat-messages::-webkit-scrollbar-thumb:hover {
                            background: #555;
                        }

                        /* Group creation modal styles */
                        .member-item:hover {
                            background-color: #f8f9fa;
                        }

                        .member-item.selected {
                            background-color: #e3f2fd;
                        }

                        .selected-member-item {
                            background-color: white;
                        }

                        .selected-member-item:hover {
                            background-color: #f8f9fa;
                        }

                        #memberList::-webkit-scrollbar,
                        #selectedMembers::-webkit-scrollbar {
                            width: 6px;
                        }

                        #memberList::-webkit-scrollbar-track,
                        #selectedMembers::-webkit-scrollbar-track {
                            background: #f1f1f1;
                        }

                        #memberList::-webkit-scrollbar-thumb,
                        #selectedMembers::-webkit-scrollbar-thumb {
                            background: #888;
                            border-radius: 3px;
                        }

                        #memberList::-webkit-scrollbar-thumb:hover,
                        #selectedMembers::-webkit-scrollbar-thumb:hover {
                            background: #555;
                        }

                        .remove-member-btn {
                            width: 24px;
                            height: 24px;
                            padding: 0;
                            display: flex;
                            align-items: center;
                            justify-content: center;
                        }