/**
 * Main Stylesheet for File Converter App
 * Organized by sections for better maintainability
 */

/* ==================== BASE STYLES ==================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* Color Palette */
    --primary-color: #cc785c;
    --primary-hover: #b86a4d;
    --primary-light: #f0e8e0;
    --primary-lighter: #fefdfb;
    
    --secondary-color: #3b82f6;
    --secondary-hover: #2563eb;
    
    --success-color: #10b981;
    --success-hover: #059669;
    
    --text-primary: #2d2d2d;
    --text-secondary: #5a5a5a;
    --text-tertiary: #8a8a8a;
    --text-quaternary: #999;
    
    --bg-primary: #ffffff;
    --bg-secondary: #f5f5f5;
    --bg-tertiary: #fafafa;
    
    --border-color: #e5e5e5;
    --border-hover: #d4d4d4;
    --border-active: #cc785c;
    
    /* Spacing */
    --spacing-xs: 4px;
    --spacing-sm: 8px;
    --spacing-md: 12px;
    --spacing-lg: 16px;
    --spacing-xl: 20px;
    --spacing-2xl: 24px;
    --spacing-3xl: 32px;
    --spacing-4xl: 48px;
    
    /* Border Radius */
    --radius-sm: 4px;
    --radius-md: 6px;
    --radius-lg: 8px;
    --radius-xl: 12px;
    --radius-full: 50%;
    
    /* Shadows */
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 2px 4px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 4px 8px rgba(0, 0, 0, 0.1);
    --shadow-xl: 2px 0 8px rgba(0, 0, 0, 0.1);
    
    /* Transitions */
    --transition-fast: 0.2s ease;
    --transition-medium: 0.3s ease;
    --transition-slow: 0.5s ease;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', sans-serif;
    background: var(--bg-secondary);
    color: var(--text-primary);
    height: 100vh;
    overflow: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* ==================== LAYOUT ==================== */
.app-container {
    display: flex;
    height: 100vh;
    flex-direction: column;
}

.desktop-layout {
    display: flex;
    flex: 1;
    overflow: hidden;
}

/* ==================== MOBILE HEADER ==================== */
.mobile-header {
    display: none;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-md) var(--spacing-lg);
    background: var(--bg-primary);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.hamburger-btn {
    width: 48px;
    height: 48px;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    background: var(--bg-primary);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all var(--transition-fast);
    flex-shrink: 0;
}

.hamburger-btn:active {
    background: var(--bg-secondary);
}

.hamburger-icon {
    width: 20px;
    height: 20px;
    display: flex;
    flex-direction: column;
    justify-content: space-around;
}

.hamburger-icon span {
    display: block;
    height: 2px;
    background: var(--text-primary);
    border-radius: 2px;
    transition: all var(--transition-medium);
}

.mobile-actions {
    display: flex;
    gap: var(--spacing-md);
    align-items: center;
}

.mobile-icon-btn {
    width: 48px;
    height: 48px;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    background: var(--bg-primary);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all var(--transition-fast);
    font-size: 20px;
    position: relative;
    flex-shrink: 0;
}

.mobile-icon-btn:active {
    background: var(--bg-secondary);
}

.mobile-user-btn {
    width: auto;
    padding: var(--spacing-sm) var(--spacing-md);
    gap: var(--spacing-sm);
}

.mobile-avatar {
    width: 32px;
    height: 32px;
    border-radius: var(--radius-full);
    background: var(--primary-color);
    color: white;
    font-weight: 600;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 14px;
}

.dropdown-arrow {
    font-size: 12px;
    color: var(--text-secondary);
}

/* ==================== SIDEBAR OVERLAY ==================== */
.sidebar-overlay {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.5);
    z-index: 999;
    opacity: 0;
    transition: opacity var(--transition-medium);
}

.sidebar-overlay.active {
    display: block;
    opacity: 1;
}

/* ==================== SIDEBAR ==================== */
.sidebar {
    width: 260px;
    background: var(--bg-primary);
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    overflow-y: auto;
}

.sidebar-header {
    padding: var(--spacing-2xl) var(--spacing-xl);
    border-bottom: 1px solid var(--border-color);
}

.sidebar-header h1 {
    font-size: 18px;
    font-weight: 600;
    color: var(--text-primary);
}

.sidebar-nav {
    padding: var(--spacing-lg) 0;
}

/* Navigation Items */
.nav-item {
    padding: 10px var(--spacing-xl);
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    transition: background var(--transition-fast);
    color: var(--text-secondary);
    font-size: 14px;
    user-select: none;
}

.nav-item:hover {
    background: var(--bg-secondary);
}

.nav-item.active {
    background: var(--primary-light);
    color: var(--primary-color);
    font-weight: 500;
}

.nav-icon {
    width: 20px;
    height: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
}

/* Submenu Styles */
.nav-item-with-submenu {
    position: relative;
}

.expand-icon {
    margin-left: auto;
    font-size: 12px;
    transition: transform var(--transition-medium);
}

.expand-icon.expanded {
    transform: rotate(90deg);
}

.submenu {
    max-height: 0;
    overflow: hidden;
    transition: max-height var(--transition-medium);
    background: var(--bg-tertiary);
}

.submenu.expanded {
    max-height: 500px;
}

.submenu-item {
    padding: var(--spacing-sm) var(--spacing-xl) var(--spacing-sm) 52px;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    transition: background var(--transition-fast);
    color: #6a6a6a;
    font-size: 13px;
    user-select: none;
}

.submenu-item:hover {
    background: #f0f0f0;
}

.submenu-item.active {
    background: #e8ddd3;
    color: var(--primary-color);
    font-weight: 500;
}

.submenu-item::before {
    content: '→';
    font-size: 12px;
    color: var(--text-quaternary);
}

/* ==================== MAIN CONTENT ==================== */
.main-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

.main-header {
    background: var(--bg-primary);
    padding: var(--spacing-xl) var(--spacing-3xl);
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.main-header h2 {
    font-size: 24px;
    font-weight: 600;
    color: var(--text-primary);
}

/* Desktop Action Icons */
.desktop-actions {
    display: flex;
    gap: var(--spacing-md);
    align-items: center;
}

.desktop-icon-btn {
    width: 48px;
    height: 48px;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    background: var(--bg-primary);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all var(--transition-fast);
    font-size: 20px;
    position: relative;
}

.desktop-icon-btn:hover {
    background: var(--bg-secondary);
    border-color: var(--border-hover);
}

.desktop-user-btn {
    width: auto;
    padding: var(--spacing-sm) var(--spacing-lg);
    gap: 10px;
    display: flex;
    align-items: center;
}

.desktop-avatar {
    width: 32px;
    height: 32px;
    border-radius: var(--radius-full);
    background: var(--primary-color);
    color: white;
    font-weight: 600;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 14px;
}

.desktop-user-name {
    font-size: 14px;
    color: var(--text-primary);
    font-weight: 500;
}

.main-body {
    flex: 1;
    overflow-y: auto;
    padding: var(--spacing-3xl);
}

/* ==================== CONTENT SECTIONS ==================== */
.content-section {
    display: none;
}

.content-section.active {
    display: block;
}

/* ==================== LOADING INDICATOR ==================== */
.loading-container {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    min-height: 400px;
    gap: var(--spacing-lg);
}

.loading-spinner {
    width: 48px;
    height: 48px;
    border: 4px solid var(--border-color);
    border-top-color: var(--primary-color);
    border-radius: var(--radius-full);
    animation: spin 1s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

.loading-container p {
    color: var(--text-secondary);
    font-size: 14px;
}

/* ==================== UPLOAD AREA ==================== */
.upload-area {
    background: var(--bg-primary);
    border: 2px dashed var(--border-hover);
    border-radius: var(--radius-xl);
    padding: var(--spacing-4xl);
    text-align: center;
    cursor: pointer;
    transition: all var(--transition-medium);
    margin-bottom: var(--spacing-2xl);
}

.upload-area:hover {
    border-color: var(--border-active);
    background: var(--primary-lighter);
}

.upload-area.dragover {
    border-color: var(--border-active);
    background: var(--primary-light);
}

.upload-icon {
    font-size: 48px;
    color: var(--primary-color);
    margin-bottom: var(--spacing-lg);
}

.upload-text {
    color: var(--text-secondary);
    font-size: 16px;
    margin-bottom: var(--spacing-sm);
}

.upload-subtext {
    color: var(--text-tertiary);
    font-size: 14px;
}

/* ==================== FILE PREVIEW ==================== */
.preview-container {
    background: var(--bg-primary);
    border-radius: var(--radius-xl);
    padding: var(--spacing-2xl);
    margin-top: var(--spacing-2xl);
    display: none;
}

.preview-container.active {
    display: block;
}

.preview-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-xl);
    flex-wrap: wrap;
    gap: var(--spacing-md);
}

.preview-header h3 {
    font-size: 16px;
    font-weight: 600;
    color: var(--text-primary);
}

.preview-actions {
    display: flex;
    gap: var(--spacing-md);
    flex-wrap: wrap;
}

.clear-btn {
    background: var(--bg-secondary);
    border: none;
    padding: var(--spacing-sm) var(--spacing-lg);
    border-radius: var(--radius-md);
    cursor: pointer;
    font-size: 14px;
    color: var(--text-secondary);
    transition: background var(--transition-fast);
}

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

.preview-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: var(--spacing-lg);
}

.preview-item {
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: var(--spacing-md);
    position: relative;
    cursor: grab;
    padding-left: 44px;
}

.preview-item.sortable-ghost {
    opacity: 0.4;
    background: var(--primary-light);
    border-style: dashed;
    border-color: var(--primary-color);
}

.preview-thumbnail {
    width: 100%;
    height: 150px;
    background: var(--bg-secondary);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: var(--spacing-md);
    overflow: hidden;
}

.preview-thumbnail img {
    max-width: 100%;
    max-height: 100%;
    object-fit: contain;
}

.preview-thumbnail.file-icon {
    font-size: 48px;
}

.preview-info {
    font-size: 13px;
    color: var(--text-secondary);
}

.preview-name {
    font-weight: 500;
    color: var(--text-primary);
    margin-bottom: var(--spacing-xs);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    display: flex;
    align-items: center;
}

.preview-size {
    color: var(--text-tertiary);
    font-size: 12px;
}

.remove-file-btn {
    position: absolute;
    top: var(--spacing-sm);
    right: var(--spacing-sm);
    background: rgba(255, 255, 255, 0.9);
    border: none;
    width: 24px;
    height: 24px;
    border-radius: var(--radius-full);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 16px;
    color: var(--primary-color);
    transition: all var(--transition-fast);
    z-index: 10;
}

.remove-file-btn:hover {
    background: var(--primary-color);
    color: white;
}

.move-controls {
    position: absolute;
    left: var(--spacing-sm);
    top: 50%;
    transform: translateY(-50%);
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
    z-index: 9;
}

.move-btn {
    background: rgba(255, 255, 255, 0.9);
    border: 1px solid var(--border-hover);
    width: 28px;
    height: 28px;
    border-radius: var(--radius-full);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 16px;
    color: var(--text-secondary);
    transition: all var(--transition-fast);
}

.move-btn:hover {
    background: var(--bg-secondary);
    color: var(--text-primary);
    border-color: var(--border-active);
}

.move-btn:disabled {
    opacity: 0.3;
    cursor: not-allowed;
}

/* ==================== CONVERSION OPTIONS ==================== */
.conversion-options {
    margin-top: var(--spacing-lg);
    padding-top: var(--spacing-lg);
    border-top: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    flex-wrap: wrap;
}

.format-label {
    font-size: 13px;
    color: var(--text-secondary);
    font-weight: 500;
}

.format-select {
    padding: var(--spacing-sm) 32px var(--spacing-sm) var(--spacing-md);
    border: 1px solid var(--border-hover);
    border-radius: var(--radius-md);
    background: var(--bg-primary);
    font-size: 14px;
    color: var(--text-primary);
    cursor: pointer;
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg width='12' height='8' viewBox='0 0 12 8' fill='none' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath d='M1 1.5L6 6.5L11 1.5' stroke='%235a5a5a' stroke-width='1.5' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 10px center;
    transition: border-color var(--transition-fast);
}

.format-select:hover {
    border-color: var(--border-active);
}

.format-select:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

/* ==================== BUTTONS ==================== */
.convert-btn {
    background: var(--primary-color);
    color: white;
    border: none;
    padding: var(--spacing-sm) var(--spacing-xl);
    border-radius: var(--radius-md);
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.convert-btn:hover {
    background: var(--primary-hover);
    transform: translateY(-1px);
}

.split-btn {
    background: var(--secondary-color);
    color: white;
    border: none;
    padding: var(--spacing-sm) var(--spacing-xl);
    border-radius: var(--radius-md);
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.split-btn:hover {
    background: var(--secondary-hover);
}

.merge-btn {
    background: var(--success-color);
    color: white;
    border: none;
    padding: var(--spacing-sm) var(--spacing-xl);
    border-radius: var(--radius-md);
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.merge-btn:hover {
    background: var(--success-hover);
}

.action-buttons {
    display: flex;
    gap: var(--spacing-md);
}

.source-format-badge {
    display: inline-block;
    background: var(--primary-light);
    color: var(--primary-color);
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--radius-sm);
    font-size: 12px;
    font-weight: 600;
    margin-left: var(--spacing-xs);
}

/* ==================== GLOBAL FORMAT SELECTOR ==================== */
.global-format-selector {
    background: var(--bg-primary);
    border-radius: var(--radius-xl);
    padding: var(--spacing-xl) var(--spacing-2xl);
    margin-bottom: var(--spacing-2xl);
    border: 2px solid var(--border-color);
    display: flex;
    align-items: center;
    gap: var(--spacing-lg);
    flex-wrap: wrap;
}

.global-format-selector .label {
    font-size: 14px;
    font-weight: 600;
    color: var(--text-primary);
}

.global-format-selector .description {
    font-size: 13px;
    color: var(--text-tertiary);
    flex: 1;
    min-width: 200px;
}

.global-format-selector select {
    padding: 10px 36px 10px 14px;
    border: 2px solid var(--primary-color);
    border-radius: var(--radius-lg);
    background: var(--bg-primary);
    font-size: 14px;
    font-weight: 500;
    color: var(--primary-color);
    cursor: pointer;
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg width='12' height='8' viewBox='0 0 12 8' fill='none' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath d='M1 1.5L6 6.5L11 1.5' stroke='%23cc785c' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 12px center;
    transition: all var(--transition-fast);
    min-width: 120px;
}

/* ==================== RESPONSIVE ==================== */
@media (max-width: 768px) {
    body {
        overflow-x: hidden;
    }

    .mobile-header {
        display: flex;
    }

    .desktop-actions {
        display: none;
    }

    .sidebar {
        position: fixed;
        left: -280px;
        top: 0;
        height: 100vh;
        width: 280px;
        z-index: 1000;
        transition: left var(--transition-medium);
        box-shadow: var(--shadow-xl);
    }

    .sidebar.mobile-open {
        left: 0;
    }

    .main-content {
        width: 100%;
    }

    .main-header {
        padding: var(--spacing-lg);
        flex-direction: column;
        align-items: flex-start;
        gap: var(--spacing-md);
    }

    .main-header h2 {
        font-size: 20px;
    }

    .main-body {
        padding: var(--spacing-lg);
    }

    .upload-area {
        padding: var(--spacing-3xl) var(--spacing-lg);
    }

    .upload-icon {
        font-size: 36px;
    }

    .preview-grid {
        grid-template-columns: 1fr;
    }

    .preview-header {
        flex-direction: column;
        align-items: stretch;
    }

    .preview-actions {
        width: 100%;
    }

    .action-buttons {
        width: 100%;
        flex-direction: column;
    }

    .convert-btn, .split-btn, .merge-btn, .clear-btn {
        width: 100%;
    }

    .global-format-selector {
        flex-direction: column;
        align-items: stretch;
    }

    .global-format-selector select {
        width: 100%;
    }

    .conversion-options {
        flex-direction: column;
        align-items: stretch;
    }

    .format-select {
        width: 100%;
    }

    .move-controls {
        display: none;
    }

    .preview-item {
        padding-left: var(--spacing-md);
    }

    .nav-item, .submenu-item {
        min-height: 44px;
    }
}

@media (min-width: 769px) {
    .desktop-actions {
        display: flex;
    }
}

@media (max-width: 480px) {
    .mobile-header {
        padding: var(--spacing-sm) var(--spacing-md);
    }

    .hamburger-btn, .mobile-icon-btn {
        width: 44px;
        height: 44px;
    }

    .mobile-actions {
        gap: var(--spacing-sm);
    }

    .sidebar {
        width: 260px;
        left: -260px;
    }
}

/* ==================== UTILITY CLASSES ==================== */
.hidden {
    display: none !important;
}

.visible {
    display: block !important;
}

.text-center {
    text-align: center;
}

.mt-0 { margin-top: 0; }
.mt-1 { margin-top: var(--spacing-sm); }
.mt-2 { margin-top: var(--spacing-md); }
.mt-3 { margin-top: var(--spacing-lg); }
.mt-4 { margin-top: var(--spacing-xl); }

.mb-0 { margin-bottom: 0; }
.mb-1 { margin-bottom: var(--spacing-sm); }
.mb-2 { margin-bottom: var(--spacing-md); }
.mb-3 { margin-bottom: var(--spacing-lg); }
.mb-4 { margin-bottom: var(--spacing-xl); }

/* ==================== SCROLLBAR STYLING ==================== */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

::-webkit-scrollbar-track {
    background: var(--bg-secondary);
}

::-webkit-scrollbar-thumb {
    background: var(--border-hover);
    border-radius: var(--radius-sm);
}

::-webkit-scrollbar-thumb:hover {
    background: var(--text-tertiary);
}