.context-menu {
    position: fixed;
    background: white;
    border: 1px solid #e5e7eb;
    border-radius: 0.375rem;
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    z-index: 1000;
    min-width: 160px;
    display: none;
}

.context-menu-item {
    padding: 0.5rem 1rem;
    cursor: pointer;
    transition: background-color 0.2s;
}

.context-menu-item:hover {
    background-color: #f3f4f6;
}

.private-chat-tab {
    transition: all 0.3s;
}

.private-chat-tab.active {
    background-color: #dbeafe;
    border-bottom: 2px solid #3b82f6;
}

.private-chat-tab:hover {
    background-color: #f3f4f6;
}

.message-container {
    display: flex;
    margin-bottom: 30px;
    padding-top: 25px;
    animation: fadeIn 0.3s ease-in;
    position: relative;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

.message-left {
    justify-content: flex-start;
}

.message-right {
    justify-content: flex-end;
}

.message-time-above {
    color: #9ca3af;
    font-size: 11px;
    position: absolute;
    top: 0;
}

.message-left .message-time-above {
    left: 0;
}

.message-right .message-time-above {
    right: 0;
}

.message-bubble {
    max-width: 70%;
    padding: 10px 14px;
    border-radius: 12px;
    position: relative;
    word-wrap: break-word;
    box-shadow: 0 1px 2px rgba(0, 0, 0, 0.1);
}

.message-left .message-bubble {
    background-color: #ffffff;
    border: 1px solid #e5e7eb;
    border-top-left-radius: 4px;
}

.message-right .message-bubble {
    background-color: #95ec69;
    border-top-right-radius: 4px;
}

.message-sender {
    font-weight: 600;
    color: #6b7280;
    font-size: 12px;
    margin-bottom: 4px;
}

.message-left .message-sender {
    text-align: left;
}

.message-right .message-sender {
    text-align: right;
}

.message-content {
    color: #1f2937;
    line-height: 1.5;
    word-break: break-word;
}

.message-right .message-content {
    color: #000000;
}

.file-message {
    display: flex;
    align-items: center;
    padding: 8px;
    background: rgba(255, 255, 255, 0.3);
    border-radius: 8px;
    margin-top: 6px;
    cursor: pointer;
    transition: background 0.2s;
}

.file-message:hover {
    background: rgba(255, 255, 255, 0.5);
}

.file-icon {
    font-size: 24px;
    margin-right: 10px;
}

.file-info {
    flex: 1;
    min-width: 0;
}

.file-name {
    font-size: 13px;
    font-weight: 500;
    color: #1f2937;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.file-size {
    font-size: 11px;
    color: #6b7280;
    margin-top: 2px;
}

.file-download-icon {
    font-size: 20px;
    color: #3b82f6;
}

.image-message {
    max-width: 200px;
    border-radius: 8px;
    margin-top: 6px;
    cursor: pointer;
    transition: transform 0.2s;
}

.image-message:hover {
    transform: scale(1.02);
}

.image-preview-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.85);
    display: none;
    justify-content: center;
    align-items: center;
    z-index: 9999;
    cursor: zoom-out;
    animation: fadeIn 0.2s ease-in;
}

.image-preview-overlay.active {
    display: flex;
}

.image-preview-container {
    position: relative;
    max-width: 90vw;
    max-height: 90vh;
    animation: zoomIn 0.3s ease-out;
}

@keyframes zoomIn {
    from { transform: scale(0.8); opacity: 0; }
    to { transform: scale(1); opacity: 1; }
}

.image-preview-container img {
    max-width: 90vw;
    max-height: 90vh;
    object-fit: contain;
    border-radius: 8px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.5);
}

.image-preview-close {
    position: absolute;
    top: -40px;
    right: 0;
    width: 36px;
    height: 36px;
    background: rgba(255, 255, 255, 0.2);
    border: none;
    border-radius: 50%;
    color: white;
    font-size: 20px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background 0.2s;
}

.image-preview-close:hover {
    background: rgba(255, 255, 255, 0.3);
}

.image-preview-info {
    position: absolute;
    bottom: -40px;
    left: 0;
    right: 0;
    text-align: center;
    color: rgba(255, 255, 255, 0.8);
    font-size: 14px;
}

.file-upload-btn {
    position: relative;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 8px;
    border-radius: 8px;
    background: #f3f4f6;
    border: 1px solid #d1d5db;
    cursor: pointer;
    transition: all 0.2s;
}

.file-upload-btn:hover {
    background: #e5e7eb;
}

.file-upload-btn input[type="file"] {
    position: absolute;
    opacity: 0;
    width: 100%;
    height: 100%;
    cursor: pointer;
}

.upload-progress {
    position: absolute;
    bottom: 0;
    left: 0;
    height: 3px;
    background: #3b82f6;
    transition: width 0.3s;
}

.system-message {
    text-align: center;
    color: #9ca3af;
    font-size: 12px;
    margin: 8px 0;
    font-style: italic;
}
.at-mention {
    color: #2563eb;
    font-weight: 600;
    cursor: pointer;
}

.at-mention:hover {
    color: #1d4ed8;
}

.at-user-item {
    padding: 8px 12px;
    cursor: pointer;
    border-radius: 6px;
    transition: background-color 0.2s;
    display: flex;
    align-items: center;
}

.at-user-item:hover, .at-user-item.active {
    background-color: #f3f4f6;
}

.at-user-item .user-name {
    flex: 1;
    font-size: 14px;
    color: #374151;
}

.at-user-item .user-badge {
    font-size: 11px;
    padding: 2px 6px;
    border-radius: 4px;
    margin-left: 8px;
}
.at-user-item.selected {
    background-color: #dbeafe;
    border: 1px solid #3b82f6;
}

.at-user-item .select-check {
    width: 18px;
    height: 18px;
    border: 2px solid #d1d5db;
    border-radius: 4px;
    margin-right: 8px;
    flex-shrink: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 12px;
    color: white;
}

.at-user-item.selected .select-check {
    background-color: #3b82f6;
    border-color: #3b82f6;
}

.at-user-item .select-check::after {
    content: '✓';
    display: none;
}

.at-user-item.selected .select-check::after {
    display: block;
}

@media (max-width: 640px) {
    #atUserPopup {
        width: calc(100% - 20px) !important;
        left: 10px !important;
        max-height: 50vh !important;
    }

    .message-bubble {
        max-width: 85%;
        padding: 8px 12px;
    }

    .image-message {
        max-width: 150px;
    }

    .file-message {
        min-width: 180px;
    }

    .file-icon {
        font-size: 20px;
        margin-right: 8px;
    }

    .file-name {
        font-size: 12px;
    }

    .file-size {
        font-size: 10px;
    }

    #chatTabs {
        font-size: 13px;
    }

    .private-chat-tab {
        padding: 8px 12px;
        font-size: 13px;
    }

    .file-upload-btn {
        padding: 6px;
    }

    main {
        padding: 12px !important;
    }

    .image-preview-container {
        max-width: 95vw;
        max-height: 85vh;
    }

    .image-preview-container img {
        max-width: 95vw;
        max-height: 85vh;
    }
}

@media (max-width: 375px) {
    .message-bubble {
        max-width: 90%;
    }

    .image-message {
        max-width: 120px;
    }

    .file-message {
        min-width: 160px;
    }
}