.upload-container {
    background-color: var(--card-bg);
    padding: 2rem;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    max-width: 600px;
    margin: 0 auto;
    text-align: center;
}

.upload-title {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text);
}

.drop-zone {
    border: 2px dashed var(--border);
    border-radius: var(--radius-md);
    padding: 2rem;
    margin-bottom: 1.5rem;
    transition: var(--transition);
    cursor: pointer;
    background-color: var(--bg);
}

.drop-zone.dragover {
    border-color: var(--primary);
    background-color: rgba(255, 109, 40, 0.1);
}

.drop-icon {
    font-size: 2.5rem;
    color: var(--primary);
    margin-bottom: 0.5rem;
}

.drop-text {
    color: var(--text-light);
    font-size: 1rem;
    margin-bottom: 0.5rem;
}

.drop-subtext {
    color: var(--text-lighter);
    font-size: 0.85rem;
}

.file-input {
    display: none;
}

/* Thêm style cho phần hiển thị file */
.file-preview {
    margin-top: 1rem;
    text-align: left;
    max-height: 200px;
    overflow-y: auto;
}

.file-item {
    display: flex;
    align-items: center;
    padding: 0.5rem;
    background-color: var(--bg);
    border-radius: var(--radius-sm);
    margin-bottom: 0.5rem;
}

.file-icon {
    margin-right: 0.5rem;
    color: var(--primary);
}

.file-name {
    flex-grow: 1;
    font-size: 0.9rem;
    color: var(--text);
    word-break: break-all;
}

.file-size {
    font-size: 0.8rem;
    color: var(--text-light);
    margin-left: 0.5rem;
}

.remove-file {
    color: var(--danger);
    cursor: pointer;
    margin-left: 0.5rem;
    font-size: 0.9rem;
}

.submit-btn {
    background-color: var(--primary);
    color: white;
    padding: 0.75rem 2rem;
    border-radius: var(--radius-md);
    border: none;
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
    width: 100%;
}

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

.submit-btn:disabled {
    background-color: var(--text-lighter);
    cursor: not-allowed;
}

.loader {
    display: none;
    width: 24px;
    height: 24px;
    border: 3px solid white;
    border-top: 3px solid transparent;
    border-radius: 50%;
    animation: spin 1s linear infinite;
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
}

.submit-btn.loading .loader {
    display: block;
}

.submit-btn.loading span {
    visibility: hidden;
}

@keyframes spin {
    0% {
        transform: translate(-50%, -50%) rotate(0deg);
    }

    100% {
        transform: translate(-50%, -50%) rotate(360deg);
    }
}

@media (max-width: 1024px) {
    .app-container {
        grid-template-columns: 240px 1fr;
    }
}

@media (max-width: 768px) {
    .app-container {
        grid-template-columns: 1fr;
        grid-template-rows: auto auto 1fr;
    }

    .header {
        grid-column: 1 / 2;
        padding: 1rem;
    }

    .sidebar {
        grid-column: 1 / 2;
        grid-row: 2 / 3;
        height: auto;
        position: static;
        display: none;
    }

    .sidebar.active {
        display: flex;
    }

    .main-content {
        grid-column: 1 / 2;
        grid-row: 3 / 4;
        padding: 1.5rem;
    }
}

@media (max-width: 480px) {
    .header-title {
        font-size: 1.25rem;
    }

    .header-actions {
        gap: 1rem;
    }

    .upload-container {
        padding: 1.5rem;
    }

    .upload-title {
        font-size: 1.25rem;
    }

    .drop-zone {
        padding: 1.5rem;
    }
}

.upload-container {
    background-color: var(--card-bg);
    padding: 2rem;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    max-width: 600px;
    margin: 0 auto;
    text-align: center;
}

.upload-title {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text);
}

.drop-zone {
    border: 2px dashed var(--border);
    border-radius: var(--radius-md);
    padding: 2rem;
    margin-bottom: 1.5rem;
    transition: var(--transition);
    cursor: pointer;
    background-color: var(--bg);
}

.drop-zone.dragover {
    border-color: var(--primary);
    background-color: rgba(255, 109, 40, 0.1);
}

.drop-icon {
    font-size: 2.5rem;
    color: var(--primary);
    margin-bottom: 0.5rem;
}

.drop-text {
    color: var(--text-light);
    font-size: 1rem;
    margin-bottom: 0.5rem;
}

.drop-subtext {
    color: var(--text-lighter);
    font-size: 0.85rem;
}

.file-input {
    display: none;
}

.file-preview {
    margin-top: 1rem;
    text-align: left;
    max-height: 200px;
    overflow-y: auto;
}

.file-item {
    display: flex;
    align-items: center;
    padding: 0.5rem;
    background-color: var(--bg);
    border-radius: var(--radius-sm);
    margin-bottom: 0.5rem;
}

.file-icon {
    margin-right: 0.5rem;
    color: var(--primary);
}

.file-name {
    flex-grow: 1;
    font-size: 0.9rem;
    color: var(--text);
    word-break: break-all;
}

.file-size {
    font-size: 0.8rem;
    color: var(--text-light);
    margin-left: 0.5rem;
}

.remove-file {
    color: var(--danger);
    cursor: pointer;
    margin-left: 0.5rem;
    font-size: 0.9rem;
}

.submit-btn {
    background-color: var(--primary);
    color: white;
    padding: 0.75rem 2rem;
    border-radius: var(--radius-md);
    border: none;
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
    width: 100%;
}

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

.submit-btn:disabled {
    background-color: var(--text-lighter);
    cursor: not-allowed;
}

.loader {
    display: none;
    width: 24px;
    height: 24px;
    border: 3px solid white;
    border-top: 3px solid transparent;
    border-radius: 50%;
    animation: spin 1s linear infinite;
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
}

.submit-btn.loading .loader {
    display: block;
}

.submit-btn.loading span {
    visibility: hidden;
}

.history-btn {
    background-color: transparent;
    color: var(--primary);
    padding: 0.5rem 1rem;
    border-radius: var(--radius-md);
    border: 1px solid var(--primary);
    font-size: 0.85rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    margin-top: 1rem;
    width: auto;
    display: inline-block;
}

.history-btn:hover {
    background-color: rgba(255, 109, 40, 0.1);
}

.history-btn i {
    margin-right: 5px;
}

@keyframes spin {
    0% {
        transform: translate(-50%, -50%) rotate(0deg);
    }

    100% {
        transform: translate(-50%, -50%) rotate(360deg);
    }
}

/* Modal Styles */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(0, 0, 0, 0.5);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1000;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s ease;
}

.modal-overlay.active {
    opacity: 1;
    visibility: visible;
}

.modal-container {
    background-color: white;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    width: 90%;
    max-width: 800px;
    max-height: 90vh;
    overflow: hidden;
}

.modal-header {
    padding: 16px 20px;
    background-color: #fff;
    border-bottom: 1px solid #e9ecef;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.modal-title {
    font-size: 1.25rem;
    font-weight: 600;
    color: #212529;
}

/* Close button for light mode */
.close-btn {
    background: none;
    border: none;
    color: #6c757d;
    font-size: 1.25rem;
    cursor: pointer;
    padding: 4px;
    transition: color 0.2s ease;
}

.close-btn:hover {
    color: #495057;
}

/* Đảm bảo nút đóng có màu phù hợp trong chế độ sáng */
[data-theme="light"] .close-btn,
:root:not([data-theme="dark"]) .close-btn {
    color: #6c757d;
}

[data-theme="light"] .close-btn:hover,
:root:not([data-theme="dark"]) .close-btn:hover {
    color: #495057;
}

.search-bar {
    padding: 12px 20px;
    background-color: #f8f9fa;
    border-bottom: 1px solid #e9ecef;
}

.search-container {
    position: relative;
}

.search-input {
    width: 100%;
    padding: 8px 12px 8px 36px;
    border: 1px solid #ced4da;
    border-radius: 4px;
    font-size: 0.9rem;
}

.search-input:focus {
    outline: none;
    border-color: #80bdff;
    box-shadow: 0 0 0 0.2rem rgba(0, 123, 255, 0.25);
}

.search-icon {
    position: absolute;
    left: 12px;
    top: 50%;
    transform: translateY(-50%);
    color: #6c757d;
}

.contributions-list {
    list-style: none;
    padding: 0;
    margin: 0;
    max-height: calc(90vh - 130px);
    overflow-y: auto;
}

.contribution-item {
    padding: 14px 20px;
    border-bottom: 1px solid #e9ecef;
    display: flex;
    align-items: center;
}

.contribution-item:last-child {
    border-bottom: none;
}

.user-avatar {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    object-fit: cover;
    margin-right: 12px;
    border: 1px solid #dee2e6;
}

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

.user-name {
    font-weight: 600;
    margin-bottom: 2px;
    color: #212529;
    font-size: 0.95rem;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.user-university {
    font-size: 0.8rem;
    color: #6c757d;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.file-info {
    margin-left: 12px;
    text-align: right;
}

.file-name {
    font-weight: 500;
    margin-bottom: 2px;
    color: #0d6efd;
    font-size: 0.9rem;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    max-width: 200px;
}

.file-time {
    font-size: 0.75rem;
    color: #6c757d;
}

.file-type {
    display: inline-block;
    width: 20px;
    text-align: center;
    color: #6c757d;
}

.no-contributions {
    padding: 30px 20px;
    text-align: center;
    color: #6c757d;
}

@media (max-width: 768px) {
    .app-container {
        grid-template-columns: 1fr;
        grid-template-rows: auto auto 1fr;
    }

    .header {
        grid-column: 1 / 2;
        padding: 1rem;
    }

    .sidebar {
        grid-column: 1 / 2;
        grid-row: 2 / 3;
        height: auto;
        position: static;
        display: none;
    }

    .sidebar.active {
        display: flex;
    }

    .main-content {
        grid-column: 1 / 2;
        grid-row: 3 / 4;
        padding: 1.5rem;
    }

    .contribution-item {
        flex-wrap: wrap;
    }

    .file-info {
        margin-left: 52px;
        margin-top: 8px;
        text-align: left;
        width: calc(100% - 52px);
    }
}

@media (max-width: 480px) {
    .header-title {
        font-size: 1.25rem;
    }

    .header-actions {
        gap: 1rem;
    }

    .upload-container {
        padding: 1.5rem;
    }

    .upload-title {
        font-size: 1.25rem;
    }

    .drop-zone {
        padding: 1.5rem;
    }
}

/* Modal dark mode (khi có data-theme="dark") */
[data-theme="dark"] .modal-container {
    background-color: var(--card-bg);
    color: var(--text);
    box-shadow: var(--shadow-lg);
}

[data-theme="dark"] .modal-header {
    background-color: var(--card-bg);
    border-bottom: 1px solid var(--border);
}

[data-theme="dark"] .modal-title {
    color: var(--text);
}

[data-theme="dark"] .close-btn {
    color: var(--text-light);
}

[data-theme="dark"] .close-btn:hover {
    color: var(--text);
}

[data-theme="dark"] .search-bar {
    background-color: var(--bg);
    border-bottom: 1px solid var(--border);
}

[data-theme="dark"] .search-input {
    background-color: var(--card-bg);
    color: var(--text);
    border: 1px solid var(--border);
}

[data-theme="dark"] .search-input:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 0.2rem rgba(74, 177, 209, 0.25);
    /* màu primary nhẹ */
}

[data-theme="dark"] .search-icon {
    color: var(--text-light);
}

[data-theme="dark"] .contribution-item {
    border-bottom: 1px solid var(--border);
}

[data-theme="dark"] .user-name {
    color: var(--text);
}

[data-theme="dark"] .user-university,
[data-theme="dark"] .file-time,
[data-theme="dark"] .file-type {
    color: var(--text-light);
}

[data-theme="dark"] .file-name {
    color: var(--primary);
}

[data-theme="dark"] .user-avatar {
    border: 1px solid var(--border);
}

[data-theme="dark"] .no-contributions {
    color: var(--text-light);
}