:root {
    --primary-color: #003399;
    --secondary-color: #CC0000;
    --accent-color: #FFFFFF;
    --background-color: #F0F2F5;
    --text-color: #333333;
    --text-color-light: #666666;
    --border-color: #DDDDDD;
    --shadow-color: rgba(0, 0, 0, 0.1);
    --font-family: 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    --sidebar-width: 250px;
    --header-height: 60px;
    --spacing-unit: 8px;
}

* {
    box-sizing: border-box;
    user-select: none;
}

input, textarea {
    user-select: text;
}

body {
    margin: 0;
    font-family: var(--font-family);
    color: var(--text-color);
    background-color: var(--background-color);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

.app-container {
    display: flex;
    flex-direction: column;
    height: 100vh;
    overflow: hidden;
}

.app-header {
    height: var(--header-height);
    background-color: var(--accent-color);
    border-bottom: 2px solid var(--primary-color);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 calc(var(--spacing-unit) * 2);
    box-shadow: 0 2px 4px var(--shadow-color);
    z-index: 100;
}

.header-left {
    display: flex;
    align-items: center;
}

.app-title {
    margin: 0;
    color: var(--primary-color);
    font-size: 1.5rem;
    font-weight: bold;
}

.header-center {
    flex: 1;
    max-width: 500px;
    margin: 0 calc(var(--spacing-unit) * 2);
}

.search-input {
    width: 100%;
    padding: var(--spacing-unit);
    border: 1px solid var(--border-color);
    border-radius: 4px;
    font-size: 1rem;
}

.header-right {
    display: flex;
    align-items: center;
    gap: calc(var(--spacing-unit) * 2);
}

.user-info {
    color: var(--text-color);
    font-weight: 500;
}

.app-body {
    display: flex;
    flex: 1;
    overflow: hidden;
}

.app-sidebar {
    width: var(--sidebar-width);
    background-color: var(--accent-color);
    border-right: 1px solid var(--border-color);
    padding: calc(var(--spacing-unit) * 2);
    overflow-y: auto;
}

.sidebar-nav {
    display: flex;
    flex-direction: column;
}

.nav-title {
    margin: calc(var(--spacing-unit) * 2) 0 var(--spacing-unit) 0;
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--text-color-light);
    text-transform: uppercase;
}

.nav-list {
    list-style: none;
    padding: 0;
    margin: 0;
}

.nav-list li {
    margin: 0;
}

.nav-link {
    display: block;
    padding: var(--spacing-unit) calc(var(--spacing-unit) * 2);
    color: var(--text-color);
    text-decoration: none;
    border-radius: 4px;
    transition: background-color 0.2s ease;
}

.nav-link:hover {
    background-color: var(--background-color);
}

.nav-link.active {
    background-color: var(--primary-color);
    color: var(--accent-color);
}

.app-main {
    flex: 1;
    overflow-y: auto;
    padding: calc(var(--spacing-unit) * 3);
}

.button {
    background-color: var(--primary-color);
    color: var(--accent-color);
    border: none;
    padding: var(--spacing-unit) calc(var(--spacing-unit) * 2);
    border-radius: 4px;
    cursor: pointer;
    font-size: 1rem;
    transition: background-color 0.2s ease;
}

.button:hover {
    background-color: var(--secondary-color);
}

.button-primary {
    background-color: var(--secondary-color);
}

.button-primary:hover {
    background-color: #AA0000;
}

.input-field {
    border: 1px solid var(--border-color);
    padding: var(--spacing-unit);
    border-radius: 4px;
    font-size: 1rem;
    width: 100%;
}

.auth-container {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
}

.auth-box {
    background-color: var(--accent-color);
    padding: calc(var(--spacing-unit) * 4);
    border-radius: 8px;
    box-shadow: 0 4px 8px var(--shadow-color);
    width: 100%;
    max-width: 400px;
}

.auth-box h1 {
    margin: 0 0 var(--spacing-unit) 0;
    color: var(--primary-color);
    text-align: center;
}

.auth-subtitle {
    text-align: center;
    color: var(--text-color-light);
    margin-bottom: calc(var(--spacing-unit) * 3);
}

.auth-tabs {
    display: flex;
    gap: var(--spacing-unit);
    margin-bottom: calc(var(--spacing-unit) * 2);
}

.auth-tab {
    flex: 1;
    padding: var(--spacing-unit);
    background-color: transparent;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    cursor: pointer;
    transition: all 0.2s ease;
}

.auth-tab.active {
    background-color: var(--primary-color);
    color: var(--accent-color);
    border-color: var(--primary-color);
}

.auth-form {
    display: flex;
    flex-direction: column;
    gap: calc(var(--spacing-unit) * 2);
}

.error-message {
    color: var(--secondary-color);
    font-size: 0.875rem;
    min-height: 1em;
}

.file-list-container {
    background-color: var(--accent-color);
    border-radius: 8px;
    padding: calc(var(--spacing-unit) * 2);
}

.file-list-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: calc(var(--spacing-unit) * 2);
    padding-bottom: calc(var(--spacing-unit) * 2);
    border-bottom: 1px solid var(--border-color);
}

.file-list-header h2 {
    margin: 0;
    color: var(--primary-color);
}

.file-actions {
    display: flex;
    gap: var(--spacing-unit);
}

.file-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: calc(var(--spacing-unit) * 2);
}

.file-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: calc(var(--spacing-unit) * 2);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.2s ease;
}

.file-item:hover {
    box-shadow: 0 2px 8px var(--shadow-color);
    border-color: var(--primary-color);
}

.file-icon {
    font-size: 3rem;
    margin-bottom: var(--spacing-unit);
}

.file-name {
    font-weight: 500;
    text-align: center;
    word-break: break-word;
    margin-bottom: var(--spacing-unit);
}

.file-size {
    font-size: 0.875rem;
    color: var(--text-color-light);
}

.file-actions-menu {
    display: flex;
    gap: calc(var(--spacing-unit) / 2);
    margin-top: var(--spacing-unit);
    flex-wrap: wrap;
}

.action-btn {
    padding: calc(var(--spacing-unit) / 2) var(--spacing-unit);
    font-size: 0.75rem;
    background-color: transparent;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    cursor: pointer;
    transition: all 0.2s ease;
}

.action-btn:hover {
    background-color: var(--primary-color);
    color: var(--accent-color);
    border-color: var(--primary-color);
}

.upload-modal, .share-modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    align-items: center;
    justify-content: center;
    z-index: 1000;
}

.upload-modal-content, .share-modal-content {
    background-color: var(--accent-color);
    border-radius: 8px;
    padding: calc(var(--spacing-unit) * 3);
    max-width: 600px;
    width: 90%;
    max-height: 85vh;
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

.upload-header, .share-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: calc(var(--spacing-unit) * 2);
    padding-bottom: calc(var(--spacing-unit) * 2);
    border-bottom: 1px solid var(--border-color);
    flex-shrink: 0;
}

.upload-header h3, .share-header h3 {
    margin: 0;
    color: var(--primary-color);
}

.close-btn {
    background: none;
    border: none;
    font-size: 2rem;
    cursor: pointer;
    color: var(--text-color-light);
    padding: 0;
    width: 32px;
    height: 32px;
}

.close-btn:hover {
    color: var(--secondary-color);
}

.drop-zone {
    border: 2px dashed var(--border-color);
    border-radius: 8px;
    padding: calc(var(--spacing-unit) * 4);
    text-align: center;
    transition: all 0.2s ease;
    flex-shrink: 0;
}

.drop-zone.drag-over {
    border-color: var(--primary-color);
    background-color: var(--background-color);
}

.drop-zone-text p {
    margin: var(--spacing-unit) 0;
    color: var(--text-color-light);
}

.upload-list {
    margin-top: calc(var(--spacing-unit) * 2);
    overflow-y: auto;
    flex: 1;
    min-height: 0;
}

.upload-item {
    padding: var(--spacing-unit);
    border: 1px solid var(--border-color);
    border-radius: 4px;
    margin-bottom: var(--spacing-unit);
}

.upload-item-name {
    font-weight: 500;
    margin-bottom: var(--spacing-unit);
}

.upload-item-progress {
    display: flex;
    flex-direction: column;
    gap: calc(var(--spacing-unit) / 2);
}

.progress-bar {
    height: 8px;
    background-color: var(--background-color);
    border-radius: 4px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background-color: var(--primary-color);
    transition: width 0.3s ease;
}

.upload-status {
    font-size: 0.875rem;
    color: var(--text-color-light);
}

.upload-status.success {
    color: #00AA00;
}

.upload-status.error {
    color: var(--secondary-color);
}

.form-group {
    margin-bottom: calc(var(--spacing-unit) * 2);
}

.form-group label {
    display: block;
    margin-bottom: var(--spacing-unit);
    font-weight: 500;
}

.share-link-container {
    display: flex;
    gap: var(--spacing-unit);
}

.share-link-container input {
    flex: 1;
}

.placeholder {
    text-align: center;
    padding: calc(var(--spacing-unit) * 4);
    color: var(--text-color-light);
    font-size: 1.25rem;
}

@media (max-width: 768px) {
    .app-header {
        flex-direction: column;
        height: auto;
        padding: var(--spacing-unit);
    }

    .header-center {
        width: 100%;
        max-width: none;
        margin: var(--spacing-unit) 0;
    }

    .header-right {
        width: 100%;
        justify-content: space-between;
    }

    .app-body {
        flex-direction: column;
    }

    .app-sidebar {
        width: 100%;
        border-right: none;
        border-bottom: 1px solid var(--border-color);
        max-height: 200px;
    }

    .file-grid {
        grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
    }
}

@media (max-width: 480px) {
    .file-grid {
        grid-template-columns: 1fr;
    }

    .file-actions {
        flex-direction: column;
    }

    .file-actions button {
        width: 100%;
    }
}

body.dark-mode {
    --background-color: #222222;
    --text-color: #EEEEEE;
    --text-color-light: #BBBBBB;
    --border-color: #444444;
    --shadow-color: rgba(255, 255, 255, 0.1);
    --accent-color: #333333;
}

.shortcuts-help-content {
    background: var(--accent-color);
    padding: calc(var(--spacing-unit) * 3);
    border-radius: 8px;
    max-width: 500px;
    width: 90%;
    max-height: 85vh;
    display: flex;
    flex-direction: column;
    box-shadow: 0 4px 20px var(--shadow-color);
}

.shortcuts-help-content h2 {
    margin: 0 0 calc(var(--spacing-unit) * 2) 0;
    color: var(--primary-color);
    flex-shrink: 0;
}

.shortcuts-list {
    margin-bottom: calc(var(--spacing-unit) * 3);
    overflow-y: auto;
    flex: 1;
    padding-right: calc(var(--spacing-unit) * 1);
}

.shortcuts-help-content .button {
    flex-shrink: 0;
    margin-top: calc(var(--spacing-unit) * 2);
}

.shortcuts-list h3 {
    margin: calc(var(--spacing-unit) * 2) 0 calc(var(--spacing-unit) * 1) 0;
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--text-color);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.shortcuts-list h3:first-child {
    margin-top: 0;
}

.shortcut-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: calc(var(--spacing-unit) * 1.5);
    border-bottom: 1px solid var(--border-color);
}

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

.shortcut-item kbd {
    background: var(--background-color);
    border: 1px solid var(--border-color);
    border-radius: 4px;
    padding: calc(var(--spacing-unit) * 0.5) calc(var(--spacing-unit) * 1);
    font-family: monospace;
    font-size: 0.875rem;
    box-shadow: 0 2px 4px var(--shadow-color);
}

.shortcut-item span {
    color: var(--text-color-light);
}

.photo-gallery {
    padding: calc(var(--spacing-unit) * 2);
}

.gallery-header {
    margin-bottom: calc(var(--spacing-unit) * 3);
}

.gallery-header h2 {
    margin: 0;
    color: var(--primary-color);
}

.gallery-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: calc(var(--spacing-unit) * 2);
}

.photo-item {
    border-radius: 8px;
    overflow: hidden;
    background: var(--accent-color);
    box-shadow: 0 2px 4px var(--shadow-color);
    cursor: pointer;
    transition: transform 0.2s, box-shadow 0.2s;
}

.photo-item:hover {
    transform: translateY(-4px);
    box-shadow: 0 4px 8px var(--shadow-color);
}

.photo-item img {
    width: 100%;
    height: 200px;
    object-fit: cover;
    display: block;
}

.photo-info {
    padding: calc(var(--spacing-unit) * 1.5);
}

.photo-name {
    display: block;
    font-weight: 600;
    margin-bottom: calc(var(--spacing-unit) * 0.5);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.photo-date {
    display: block;
    font-size: 0.875rem;
    color: var(--text-color-light);
}

.empty-state {
    text-align: center;
    padding: calc(var(--spacing-unit) * 4);
    color: var(--text-color-light);
}

.preview-modal {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.9);
    z-index: 1000;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: calc(var(--spacing-unit) * 2);
}

.preview-container {
    background: var(--accent-color);
    border-radius: 8px;
    max-width: 90vw;
    max-height: 90vh;
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

.preview-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: calc(var(--spacing-unit) * 2);
    border-bottom: 1px solid var(--border-color);
}

.preview-info h3 {
    margin: 0 0 calc(var(--spacing-unit) * 0.5) 0;
    font-size: 1.25rem;
}

.preview-info p {
    margin: 0;
    color: var(--text-color-light);
    font-size: 0.875rem;
}

.preview-actions {
    display: flex;
    gap: calc(var(--spacing-unit) * 1);
}

.btn-icon {
    background: none;
    border: 1px solid var(--border-color);
    padding: calc(var(--spacing-unit) * 1);
    border-radius: 4px;
    cursor: pointer;
    font-size: 1.2rem;
    transition: background 0.2s;
}

.btn-icon:hover {
    background: var(--background-color);
}

.preview-content {
    flex: 1;
    overflow: auto;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: calc(var(--spacing-unit) * 2);
    background: #000;
}

.preview-content img,
.preview-content video,
.preview-content audio,
.preview-content iframe {
    max-width: 100%;
    max-height: 100%;
    object-fit: contain;
}

.preview-content iframe {
    width: 100%;
    height: 70vh;
    border: none;
}

.preview-content pre {
    background: var(--background-color);
    padding: calc(var(--spacing-unit) * 2);
    border-radius: 4px;
    overflow: auto;
    max-width: 100%;
    color: var(--text-color);
    white-space: pre-wrap;
    word-wrap: break-word;
}

.no-preview {
    text-align: center;
    color: #fff;
}

.no-preview p {
    margin-bottom: calc(var(--spacing-unit) * 2);
}

.search-results {
    padding: calc(var(--spacing-unit) * 2);
}

.search-results h2 {
    margin: 0 0 calc(var(--spacing-unit) * 2) 0;
    color: var(--primary-color);
}