/* ======================
   CSS CUSTOM PROPERTIES
   ====================== */
:root {
    /* Primary Colors */
    --primary-color: #4f46e5;
    --primary-dark: #4338ca;
    --primary-light: #6366f1;
    
    /* Secondary Colors */
    --secondary-color: #06b6d4;
    --secondary-dark: #0891b2;
    --secondary-light: #67e8f9;
    
    /* Accent Colors */
    --accent-color: #8b5cf6;
    --accent-dark: #7c3aed;
    
    /* Status Colors */
    --success-color: #10b981;
    --warning-color: #f59e0b;
    --error-color: #ef4444;
    --info-color: #3b82f6;
    
    /* Neutral Colors */
    --text-primary: #1f2937;
    --text-secondary: #6b7280;
    --text-muted: #9ca3af;
    --border-color: #e5e7eb;
    --background-primary: #ffffff;
    --background-secondary: #f9fafb;
    --background-tertiary: #f3f4f6;
    
    /* Gradients */
    --gradient-primary: linear-gradient(135deg, var(--primary-color) 0%, var(--primary-light) 100%);
    --gradient-secondary: linear-gradient(135deg, var(--secondary-color) 0%, var(--secondary-light) 100%);
    --gradient-accent: linear-gradient(135deg, var(--accent-color) 0%, var(--accent-dark) 100%);
    --gradient-success: linear-gradient(135deg, #10b981 0%, #059669 100%);
    --gradient-warning: linear-gradient(135deg, #f59e0b 0%, #d97706 100%);
    --gradient-error: linear-gradient(135deg, #ef4444 0%, #dc2626 100%);
    
    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    
    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    
    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    
    /* Transitions */
    --transition-fast: 0.15s ease-in-out;
    --transition-normal: 0.3s ease-in-out;
    --transition-slow: 0.5s ease-in-out;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    background: linear-gradient(135deg, #4f46e5 0%, #06b6d4 100%);
    min-height: 100vh;
}

/* ======================
   MAIN LAYOUT
   ====================== */
.base64-converter-page {
    min-height: 100vh;
    padding: var(--spacing-xl) var(--spacing-md);
    background: linear-gradient(135deg, #4f46e5 0%, #06b6d4 100%);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    background: var(--background-primary);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-xl);
    overflow: hidden;
}

/* ======================
   HEADER SECTION
   ====================== */
.header-section {
    background: var(--gradient-primary);
    color: white;
    padding: var(--spacing-2xl);
    position: relative;
    overflow: hidden;
}

.header-section::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><defs><pattern id="grain" width="100" height="100" patternUnits="userSpaceOnUse"><circle cx="25" cy="25" r="1" fill="rgba(255,255,255,0.1)"/><circle cx="75" cy="75" r="1" fill="rgba(255,255,255,0.1)"/><circle cx="50" cy="10" r="0.5" fill="rgba(255,255,255,0.05)"/></pattern></defs><rect width="100" height="100" fill="url(%23grain)"/></svg>');
    opacity: 0.3;
}

.header-content {
    position: relative;
    z-index: 1;
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: var(--spacing-xl);
}

.header-text h1 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: var(--spacing-sm);
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.header-text h1 i {
    font-size: 2rem;
    opacity: 0.9;
}

.header-description {
    font-size: 1.1rem;
    opacity: 0.9;
    line-height: 1.6;
    max-width: 600px;
}

.header-stats {
    display: flex;
    gap: var(--spacing-lg);
}

.stat-item {
    text-align: center;
    background: rgba(255, 255, 255, 0.1);
    padding: var(--spacing-md);
    border-radius: var(--radius-lg);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.stat-number {
    font-size: 1.8rem;
    font-weight: 700;
    display: block;
}

.stat-label {
    font-size: 0.9rem;
    opacity: 0.8;
    margin-top: var(--spacing-xs);
}

/* ======================
   TEMPLATES SECTION
   ====================== */
.templates-section {
    padding: var(--spacing-2xl);
    background: var(--background-secondary);
}

.templates-section h2 {
    font-size: 1.8rem;
    color: var(--text-primary);
    margin-bottom: var(--spacing-xl);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.template-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-lg);
}

.template-card {
    background: var(--background-primary);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    box-shadow: var(--shadow-md);
    cursor: pointer;
    transition: all var(--transition-normal);
    border: 2px solid transparent;
    position: relative;
    overflow: hidden;
}

.template-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: var(--gradient-primary);
    transform: scaleX(0);
    transition: transform var(--transition-normal);
}

.template-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary-color);
}

.template-card:hover::before {
    transform: scaleX(1);
}

.template-card.active {
    border-color: var(--primary-color);
    background: linear-gradient(135deg, rgba(79, 70, 229, 0.05) 0%, rgba(6, 182, 212, 0.05) 100%);
}

.template-card.active::before {
    transform: scaleX(1);
}

.template-icon {
    width: 60px;
    height: 60px;
    background: var(--gradient-primary);
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: var(--spacing-md);
    color: white;
    font-size: 1.5rem;
}

.template-content h3 {
    font-size: 1.2rem;
    color: var(--text-primary);
    margin-bottom: var(--spacing-sm);
}

.template-content p {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-md);
    font-size: 0.9rem;
}

.template-settings {
    background: var(--background-tertiary);
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--radius-sm);
    font-size: 0.8rem;
    color: var(--text-muted);
    font-family: 'Courier New', monospace;
}

/* ======================
   TOOL INTERFACE
   ====================== */
.tool-interface {
    padding: var(--spacing-2xl);
}

/* Tab Navigation */
.tab-navigation {
    display: flex;
    background: var(--background-tertiary);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xs);
    margin-bottom: var(--spacing-xl);
    gap: var(--spacing-xs);
}

.tab-btn {
    flex: 1;
    padding: var(--spacing-md) var(--spacing-lg);
    border: none;
    background: transparent;
    color: var(--text-secondary);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-normal);
    font-weight: 500;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
}

.tab-btn:hover {
    background: var(--background-primary);
    color: var(--text-primary);
}

.tab-btn.active {
    background: var(--gradient-primary);
    color: white;
    box-shadow: var(--shadow-md);
}

/* Tab Content */
.tab-content {
    position: relative;
}

.tab-pane {
    display: none;
    animation: fadeIn 0.3s ease-in-out;
}

.tab-pane.active {
    display: block;
}

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

/* ======================
   CONVERTER CONTAINER
   ====================== */
.converter-container {
    background: var(--background-primary);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    overflow: hidden;
}

.input-section,
.output-section {
    padding: var(--spacing-lg);
}

.input-section {
    border-bottom: 1px solid var(--border-color);
}

.input-header,
.output-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-md);
}

.input-header label,
.output-header label {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-primary);
}

.input-controls,
.output-controls {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.control-btn {
    background: var(--background-tertiary);
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: all var(--transition-normal);
    font-size: 0.9rem;
}

.control-btn:hover {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

.char-count {
    font-size: 0.8rem;
    color: var(--text-muted);
    margin-left: var(--spacing-sm);
}

textarea {
    width: 100%;
    min-height: 150px;
    padding: var(--spacing-md);
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    font-family: 'Courier New', monospace;
    font-size: 0.9rem;
    line-height: 1.5;
    resize: vertical;
    transition: all var(--transition-normal);
    background: var(--background-primary);
    color: var(--text-primary);
}

textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.1);
}

textarea[readonly] {
    background: var(--background-secondary);
    cursor: default;
}

.input-info,
.output-info {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: var(--spacing-sm);
    font-size: 0.8rem;
    color: var(--text-muted);
}

.encoding-info,
.conversion-info {
    display: flex;
    gap: var(--spacing-md);
}

.encoding-info span,
.conversion-info span {
    background: var(--background-tertiary);
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--radius-sm);
}

/* ======================
   CONVERSION CONTROLS
   ====================== */
.conversion-controls {
    padding: var(--spacing-lg);
    background: var(--background-secondary);
    border-top: 1px solid var(--border-color);
    border-bottom: 1px solid var(--border-color);
}

.action-buttons {
    display: flex;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
    flex-wrap: wrap;
    justify-content: center;
}

.action-btn {
    padding: var(--spacing-md) var(--spacing-xl);
    border: none;
    border-radius: var(--radius-lg);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-normal);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    box-shadow: var(--shadow-md);
    min-width: 140px;
    justify-content: center;
}

.action-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none !important;
}

.action-btn.primary {
    background: var(--gradient-primary);
    color: white;
}

.action-btn.secondary {
    background: var(--background-primary);
    color: var(--text-primary);
    border: 2px solid var(--border-color);
}

.action-btn:not(:disabled):hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.conversion-options {
    display: flex;
    gap: var(--spacing-lg);
    justify-content: center;
    flex-wrap: wrap;
}

/* Checkbox Styling */
.checkbox-label {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    cursor: pointer;
    font-size: 0.9rem;
    color: var(--text-primary);
}

.checkbox-label input[type="checkbox"] {
    display: none;
}

.checkmark {
    width: 18px;
    height: 18px;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-sm);
    position: relative;
    transition: all var(--transition-normal);
    background: var(--background-primary);
}

.checkbox-label input[type="checkbox"]:checked + .checkmark {
    background: var(--gradient-primary);
    border-color: var(--primary-color);
}

.checkbox-label input[type="checkbox"]:checked + .checkmark::after {
    content: '✓';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    color: white;
    font-weight: bold;
    font-size: 12px;
}

/* ======================
   FILE CONVERTER
   ====================== */
.file-converter-container {
    background: var(--background-primary);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    overflow: hidden;
}

.file-upload-section {
    padding: var(--spacing-xl);
}

.upload-area {
    border: 2px dashed var(--border-color);
    border-radius: var(--radius-xl);
    padding: var(--spacing-2xl);
    text-align: center;
    background: var(--background-secondary);
    transition: all var(--transition-normal);
    cursor: pointer;
    position: relative;
    overflow: hidden;
}

.upload-area::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--gradient-primary);
    opacity: 0;
    transition: opacity var(--transition-normal);
}

.upload-area:hover,
.upload-area.dragover {
    border-color: var(--primary-color);
    background: rgba(79, 70, 229, 0.05);
    transform: scale(1.02);
}

.upload-area.dragover::before {
    opacity: 0.1;
}

.upload-content {
    position: relative;
    z-index: 1;
}

.upload-icon {
    font-size: 4rem;
    color: var(--primary-color);
    margin-bottom: var(--spacing-lg);
    transition: all var(--transition-normal);
}

.upload-area:hover .upload-icon {
    transform: scale(1.1);
    color: var(--primary-dark);
}

.upload-text h3 {
    font-size: 1.5rem;
    color: var(--text-primary);
    margin-bottom: var(--spacing-sm);
}

.upload-text p {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-xl);
}

.upload-btn {
    background: var(--gradient-primary);
    color: white;
    border: none;
    padding: var(--spacing-md) var(--spacing-xl);
    border-radius: var(--radius-lg);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-normal);
    box-shadow: var(--shadow-md);
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.upload-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.upload-info {
    margin-top: var(--spacing-xl);
    display: flex;
    justify-content: space-between;
    gap: var(--spacing-lg);
    padding-top: var(--spacing-lg);
    border-top: 1px solid var(--border-color);
}

.supported-types,
.file-limits {
    font-size: 0.9rem;
    color: var(--text-secondary);
}

/* ======================
   BATCH PROCESSING
   ====================== */
.batch-container {
    background: var(--background-primary);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    overflow: hidden;
}

.batch-input-section,
.batch-output-section {
    padding: var(--spacing-xl);
}

.batch-input-section {
    border-bottom: 1px solid var(--border-color);
}

.batch-header {
    margin-bottom: var(--spacing-lg);
}

.batch-header h3 {
    color: var(--text-primary);
    margin-bottom: var(--spacing-sm);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.batch-header p {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.batch-controls {
    display: flex;
    gap: var(--spacing-md);
    margin-top: var(--spacing-lg);
    justify-content: center;
    flex-wrap: wrap;
}

.batch-results h4 {
    color: var(--text-primary);
    margin-bottom: var(--spacing-md);
}

.batch-stats {
    display: flex;
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
    font-size: 0.9rem;
}

.batch-stats span {
    background: var(--background-tertiary);
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--radius-sm);
    color: var(--text-secondary);
}

/* ======================
   ADVANCED OPTIONS
   ====================== */
.advanced-options {
    background: var(--background-secondary);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
}

.options-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-xl);
}

.option-group {
    background: var(--background-primary);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    box-shadow: var(--shadow-sm);
}

.option-group h4 {
    color: var(--text-primary);
    margin-bottom: var(--spacing-lg);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: 1.1rem;
}

.option-item {
    margin-bottom: var(--spacing-lg);
}

.option-item:last-child {
    margin-bottom: 0;
}

.option-item label {
    display: block;
    color: var(--text-primary);
    font-weight: 500;
    margin-bottom: var(--spacing-sm);
}

.option-item select,
.option-item input[type="number"] {
    width: 100%;
    padding: var(--spacing-md);
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    font-size: 1rem;
    background: var(--background-primary);
    color: var(--text-primary);
    transition: all var(--transition-normal);
}

.option-item select:focus,
.option-item input[type="number"]:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.1);
}

.checkbox-item {
    margin-bottom: var(--spacing-md);
}

/* ======================
   HISTORY PANEL
   ====================== */
.history-panel {
    background: var(--background-primary);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    margin: var(--spacing-xl) var(--spacing-2xl);
    overflow: hidden;
}

.panel-header {
    background: var(--background-tertiary);
    padding: var(--spacing-lg);
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 1px solid var(--border-color);
}

.panel-header h3 {
    color: var(--text-primary);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.clear-history-btn {
    background: var(--gradient-error);
    color: white;
    border: none;
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-normal);
    font-size: 0.9rem;
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

.clear-history-btn:hover {
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

.history-list {
    padding: var(--spacing-lg);
    max-height: 300px;
    overflow-y: auto;
}

.empty-state {
    text-align: center;
    padding: var(--spacing-2xl);
    color: var(--text-secondary);
}

.empty-state i {
    font-size: 3rem;
    margin-bottom: var(--spacing-md);
    opacity: 0.5;
}

/* ======================
   HELP SECTION
   ====================== */
.help-section {
    padding: var(--spacing-2xl);
    background: var(--background-secondary);
}

.help-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-lg);
}

.help-card {
    background: var(--background-primary);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-normal);
}

.help-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.help-icon {
    width: 50px;
    height: 50px;
    background: var(--gradient-secondary);
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: var(--spacing-md);
    color: white;
    font-size: 1.2rem;
}

.help-content h4 {
    color: var(--text-primary);
    margin-bottom: var(--spacing-sm);
}

.help-content p {
    color: var(--text-secondary);
    font-size: 0.9rem;
    line-height: 1.6;
}

/* ======================
   BLOG SECTION
   ====================== */
.blog-section {
    padding: var(--spacing-2xl);
    border-top: 1px solid var(--border-color);
}

.blog-section h2 {
    font-size: 1.8rem;
    color: var(--text-primary);
    margin-bottom: var(--spacing-xl);
    text-align: center;
}

.blog-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
    gap: var(--spacing-xl);
}

.blog-card {
    background: var(--background-primary);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
    box-shadow: var(--shadow-md);
}

.blog-card h3 {
    color: var(--text-primary);
    margin-bottom: var(--spacing-md);
    font-size: 1.3rem;
}

.blog-card p {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-md);
    line-height: 1.6;
}

.blog-card ul {
    list-style: none;
    padding: 0;
}

.blog-card li {
    padding: var(--spacing-sm) 0;
    border-bottom: 1px solid var(--border-color);
    color: var(--text-secondary);
}

.blog-card li:last-child {
    border-bottom: none;
}

.blog-card li strong {
    color: var(--primary-color);
}

/* ======================
   NOTIFICATION SYSTEM
   ====================== */
.notification-container {
    position: fixed;
    top: 20px;
    right: 20px;
    z-index: 10000;
    pointer-events: none;
}

.notification {
    background: var(--background-primary);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-xl);
    margin-bottom: var(--spacing-md);
    overflow: hidden;
    transform: translateX(100%);
    transition: all var(--transition-normal);
    pointer-events: auto;
    border-left: 4px solid var(--info-color);
}

.notification.show {
    transform: translateX(0);
}

.notification.success {
    border-left-color: var(--success-color);
}

.notification.error {
    border-left-color: var(--error-color);
}

.notification.warning {
    border-left-color: var(--warning-color);
}

.notification-content {
    display: flex;
    align-items: center;
    padding: var(--spacing-md);
    gap: var(--spacing-md);
}

.notification-icon {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 1rem;
}

.notification.success .notification-icon {
    background: var(--success-color);
}

.notification.error .notification-icon {
    background: var(--error-color);
}

.notification.warning .notification-icon {
    background: var(--warning-color);
}

.notification.info .notification-icon {
    background: var(--info-color);
}

.notification-text {
    flex: 1;
    color: var(--text-primary);
    font-size: 0.9rem;
    line-height: 1.4;
}

.notification-close {
    background: none;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    padding: var(--spacing-xs);
    border-radius: var(--radius-sm);
    transition: all var(--transition-fast);
}

.notification-close:hover {
    background: var(--background-tertiary);
    color: var(--text-primary);
}

/* ======================
   FILE ITEMS
   ====================== */
.file-item {
    background: var(--background-secondary);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    margin-bottom: var(--spacing-md);
    border: 2px solid var(--border-color);
    transition: all var(--transition-normal);
}

.file-item:hover {
    border-color: var(--primary-color);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.file-item:last-child {
    margin-bottom: 0;
}

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

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

.file-icon {
    width: 40px;
    height: 40px;
    background: var(--gradient-primary);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 1.2rem;
}

.file-details h4 {
    color: var(--text-primary);
    margin-bottom: var(--spacing-xs);
    font-size: 1rem;
}

.file-meta {
    display: flex;
    gap: var(--spacing-md);
    font-size: 0.8rem;
    color: var(--text-secondary);
}

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

.file-action-btn {
    background: none;
    border: 2px solid var(--border-color);
    color: var(--text-secondary);
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: all var(--transition-normal);
    font-size: 0.8rem;
}

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

.file-action-btn.danger:hover {
    border-color: var(--error-color);
    color: var(--error-color);
}

/* ======================
   HISTORY ITEMS
   ====================== */
.history-item {
    background: var(--background-secondary);
    border-radius: var(--radius-md);
    padding: var(--spacing-md);
    margin-bottom: var(--spacing-md);
    border: 1px solid var(--border-color);
    transition: all var(--transition-normal);
}

.history-item:hover {
    border-color: var(--primary-color);
    transform: translateY(-1px);
    box-shadow: var(--shadow-sm);
}

.history-item:last-child {
    margin-bottom: 0;
}

.history-info {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.history-info h4 {
    color: var(--text-primary);
    font-size: 0.9rem;
    margin-bottom: var(--spacing-xs);
}

.history-info p {
    color: var(--text-secondary);
    font-size: 0.8rem;
}

.history-actions {
    display: flex;
    gap: var(--spacing-xs);
}

/* ======================
   RESPONSIVE DESIGN
   ====================== */
@media (max-width: 1024px) {
    .header-content {
        flex-direction: column;
        text-align: center;
        gap: var(--spacing-lg);
    }
    
    .header-stats {
        justify-content: center;
    }
    
    .template-grid {
        grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    }
    
    .options-grid {
        grid-template-columns: 1fr;
    }
    
    .blog-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 768px) {
    .base64-converter-page {
        padding: var(--spacing-md);
    }
    
    .header-section {
        padding: var(--spacing-xl);
    }
    
    .header-text h1 {
        font-size: 2rem;
    }
    
    .header-stats {
        flex-direction: column;
        gap: var(--spacing-md);
    }
    
    .stat-item {
        padding: var(--spacing-sm) var(--spacing-md);
    }
    
    .templates-section,
    .tool-interface,
    .help-section,
    .blog-section {
        padding: var(--spacing-xl);
    }
    
    .template-grid {
        grid-template-columns: 1fr;
    }
    
    .tab-navigation {
        flex-direction: column;
    }
    
    .tab-btn {
        justify-content: flex-start;
    }
    
    .action-buttons {
        flex-direction: column;
    }
    
    .action-btn {
        width: 100%;
    }
    
    .conversion-options {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .input-controls,
    .output-controls {
        flex-wrap: wrap;
    }
    
    .char-count {
        margin-left: 0;
        margin-top: var(--spacing-xs);
    }
    
    .upload-area {
        padding: var(--spacing-xl);
    }
    
    .upload-icon {
        font-size: 3rem;
    }
    
    .upload-info {
        flex-direction: column;
        gap: var(--spacing-md);
        text-align: center;
    }
    
    .batch-controls {
        flex-direction: column;
    }
    
    .batch-stats {
        flex-direction: column;
        gap: var(--spacing-sm);
    }
    
    .help-grid {
        grid-template-columns: 1fr;
    }
    
    .file-header {
        flex-direction: column;
        gap: var(--spacing-md);
        align-items: flex-start;
    }
    
    .file-actions {
        width: 100%;
        justify-content: flex-end;
    }
    
    .history-panel {
        margin: var(--spacing-xl) var(--spacing-md);
    }
}

@media (max-width: 480px) {
    .header-text h1 {
        font-size: 1.8rem;
    }
    
    .header-description {
        font-size: 1rem;
    }
    
    .upload-text h3 {
        font-size: 1.2rem;
    }
    
    .upload-btn {
        padding: var(--spacing-sm) var(--spacing-lg);
        font-size: 0.9rem;
    }
    
    .template-card {
        padding: var(--spacing-md);
    }
    
    .template-icon {
        width: 50px;
        height: 50px;
        font-size: 1.2rem;
    }
    
    .option-group {
        padding: var(--spacing-md);
    }
    
    .notification-container {
        left: 10px;
        right: 10px;
        top: 10px;
    }
    
    .notification {
        transform: translateY(-100%);
    }
    
    .notification.show {
        transform: translateY(0);
    }
}

/* ======================
   DARK MODE SUPPORT
   ====================== */
@media (prefers-color-scheme: dark) {
    :root {
        --text-primary: #f9fafb;
        --text-secondary: #d1d5db;
        --text-muted: #9ca3af;
        --border-color: #374151;
        --background-primary: #1f2937;
        --background-secondary: #111827;
        --background-tertiary: #374151;
    }
    
    .upload-area {
        background: var(--background-secondary);
    }
    
    .file-item {
        background: var(--background-primary);
    }
    
    .template-card {
        background: var(--background-primary);
    }
    
    .help-card {
        background: var(--background-primary);
    }
    
    .blog-card {
        background: var(--background-primary);
    }
    
    .history-item {
        background: var(--background-primary);
    }
}

/* ======================
   PRINT STYLES
   ====================== */
@media print {
    .base64-converter-page {
        background: white !important;
    }
    
    .container {
        box-shadow: none !important;
    }
    
    .header-section {
        background: #4f46e5 !important;
        -webkit-print-color-adjust: exact;
        color-adjust: exact;
    }
    
    .notification-container,
    .action-buttons,
    .conversion-options,
    .file-actions,
    .history-actions {
        display: none !important;
    }
}

/* ======================
   ACCESSIBILITY
   ====================== */
@media (prefers-reduced-motion: reduce) {
    * {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

/* Focus styles for keyboard navigation */
.upload-btn:focus,
.action-btn:focus,
.tab-btn:focus,
.template-card:focus,
.control-btn:focus,
select:focus,
input:focus,
textarea:focus,
button:focus {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

/* High contrast mode support */
@media (prefers-contrast: high) {
    :root {
        --border-color: #000000;
        --text-secondary: #000000;
    }
    
    .template-card,
    .help-card,
    .blog-card,
    .file-item,
    .history-item {
        border: 2px solid #000000;
    }
}