/* Base Styles - High Contrast for Accessibility */
:root {
    --primary-color: #0056b3;
    --primary-dark: #003d7a;
    --secondary-color: #6c757d;
    --success-color: #28a745;
    --error-color: #dc3545;
    --warning-color: #ffc107;
    --background-color: #ffffff;
    --text-color: #1a1a1a;
    --light-gray: #f8f9fa;
    --medium-gray: #e9ecef;
    --dark-gray: #6c757d;
    --border-color: #dee2e6;
    --focus-outline: 3px solid #0056b3;
    --box1-color: #ff6b6b;
    --box2-color: #ffd166;
    --box3-color: #06d6a0;
    
    --font-size-large: 1.2rem;
    --font-size-medium: 1rem;
    --font-size-small: 0.875rem;
    
    --spacing-small: 0.5rem;
    --spacing-medium: 1rem;
    --spacing-large: 1.5rem;
    --spacing-xl: 2rem;
    
    --border-radius: 8px;
    --box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
    --transition: all 0.2s ease;
}

/* Dark mode preference */
@media (prefers-color-scheme: dark) {
    :root {
        --background-color: #1a1a1a;
        --text-color: #f8f9fa;
        --light-gray: #212529;
        --medium-gray: #343a40;
        --dark-gray: #adb5bd;
        --border-color: #495057;
    }
}

/* Reset and Base */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--background-color);
    min-height: 100vh;
    padding: 0;
    margin: 0;
}

/* Accessibility: Skip Link */
.skip-link {
    position: absolute;
    top: -40px;
    left: 0;
    background: var(--primary-color);
    color: white;
    padding: var(--spacing-small) var(--spacing-medium);
    z-index: 100;
    text-decoration: none;
    font-weight: bold;
    border-radius: 0 0 var(--border-radius) var(--border-radius);
}

.skip-link:focus {
    top: 0;
    outline: var(--focus-outline);
    outline-offset: 2px;
}

/* Header */
header {
    background-color: var(--primary-color);
    color: white;
    padding: var(--spacing-large);
    text-align: center;
    border-bottom: 4px solid var(--primary-dark);
}

header h1 {
    font-size: 2rem;
    margin-bottom: var(--spacing-small);
}

header p {
    font-size: var(--font-size-medium);
    opacity: 0.9;
}

/* Navigation */
nav {
    background-color: var(--light-gray);
    padding: var(--spacing-medium);
    border-bottom: 1px solid var(--border-color);
}

nav ul {
    display: flex;
    justify-content: center;
    list-style: none;
    gap: var(--spacing-medium);
    flex-wrap: wrap;
}

nav button {
    background: transparent;
    border: 2px solid var(--primary-color);
    color: var(--primary-color);
    padding: var(--spacing-small) var(--spacing-large);
    font-size: var(--font-size-medium);
    cursor: pointer;
    border-radius: var(--border-radius);
    transition: var(--transition);
    font-weight: 500;
}

nav button:hover,
nav button:focus {
    background-color: var(--primary-color);
    color: white;
    outline: none;
}

nav button[aria-pressed="true"],
nav button.active {
    background-color: var(--primary-color);
    color: white;
}

/* Main Content */
main {
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--spacing-large);
    min-height: calc(100vh - 200px);
}

/* Sections */
.section {
    display: none;
    animation: fadeIn 0.3s ease;
}

.section.active {
    display: block;
}

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

/* Headings */
h1, h2, h3 {
    margin-bottom: var(--spacing-medium);
    line-height: 1.2;
}

h2 {
    font-size: var(--font-size-large);
    color: var(--primary-color);
    border-bottom: 2px solid var(--primary-color);
    padding-bottom: var(--spacing-small);
}

h3 {
    font-size: var(--font-size-medium);
    color: var(--dark-gray);
}

/* Form Styles */
.form-group {
    margin-bottom: var(--spacing-large);
}

.form-group label {
    display: block;
    margin-bottom: var(--spacing-small);
    font-weight: 600;
    font-size: var(--font-size-medium);
}

.form-group textarea,
.form-group input[type="text"],
.form-group input[type="file"] {
    width: 100%;
    padding: var(--spacing-medium);
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius);
    font-size: var(--font-size-medium);
    font-family: inherit;
    transition: var(--transition);
    background-color: var(--background-color);
    color: var(--text-color);
}

.form-group textarea:focus,
.form-group input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(0, 86, 179, 0.1);
}

.form-group textarea::placeholder,
.form-group input::placeholder {
    color: var(--dark-gray);
    opacity: 0.7;
}

.help-text {
    display: block;
    font-size: var(--font-size-small);
    color: var(--dark-gray);
    margin-top: var(--spacing-small);
}

.error-message {
    color: var(--error-color);
    font-size: var(--font-size-small);
    margin-top: var(--spacing-small);
    display: block;
}

/* Buttons */
button {
    font-family: inherit;
    font-size: var(--font-size-medium);
    padding: var(--spacing-small) var(--spacing-large);
    border: none;
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: var(--transition);
    font-weight: 500;
}

button:focus {
    outline: var(--focus-outline);
    outline-offset: 2px;
}

button:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

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

.primary:hover:not(:disabled) {
    background-color: var(--primary-dark);
}

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

.secondary:hover:not(:disabled) {
    background-color: var(--dark-gray);
}

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

.success:hover:not(:disabled) {
    background-color: #218838;
}

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

.error:hover:not(:disabled) {
    background-color: #c82333;
}

.form-actions {
    display: flex;
    gap: var(--spacing-medium);
    flex-wrap: wrap;
}

/* Card List */
#card-list {
    margin-top: var(--spacing-xl);
}

.info-message {
    text-align: center;
    padding: var(--spacing-large);
    color: var(--dark-gray);
    font-size: var(--font-size-medium);
}

.cards-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: var(--spacing-medium);
    list-style: none;
}

.card-item {
    background-color: var(--light-gray);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    padding: var(--spacing-medium);
    box-shadow: var(--box-shadow);
    transition: var(--transition);
}

.card-item:hover {
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.15);
}

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

.card-item .card-question {
    font-weight: 600;
    font-size: var(--font-size-medium);
    margin-bottom: var(--spacing-small);
    color: var(--text-color);
}

.card-item .card-answer {
    font-size: var(--font-size-small);
    color: var(--dark-gray);
    margin-bottom: var(--spacing-small);
}

.card-item .card-box {
    display: inline-block;
    padding: var(--spacing-small) var(--spacing-medium);
    border-radius: var(--border-radius);
    font-size: var(--font-size-small);
    font-weight: 600;
    color: white;
}

.card-item .box-0 { background-color: var(--box1-color); }
.card-item .box-1 { background-color: var(--box2-color); }
.card-item .box-2 { background-color: var(--box3-color); }

.card-item .delete-btn {
    background: transparent;
    color: var(--error-color);
    border: 1px solid var(--error-color);
    padding: var(--spacing-small);
    font-size: var(--font-size-small);
}

.card-item .delete-btn:hover {
    background-color: var(--error-color);
    color: white;
}

/* Box Selector */
.box-selector {
    margin-bottom: var(--spacing-xl);
}

.boxes {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-medium);
}

.box-button {
    background-color: var(--light-gray);
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius);
    padding: var(--spacing-large);
    text-align: left;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    flex-direction: column;
    align-items: center;
}

.box-button:hover,
.box-button:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(0, 86, 179, 0.1);
    outline: none;
}

.box-button:active {
    transform: translateY(2px);
}

.box-name {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: var(--spacing-small);
}

.box-desc {
    font-size: var(--font-size-medium);
    color: var(--dark-gray);
    margin-bottom: var(--spacing-medium);
}

.card-count {
    font-size: var(--font-size-medium);
    color: var(--primary-color);
    font-weight: 600;
}

/* Review Area */
.review-area {
    max-width: 600px;
    margin: 0 auto;
}

.review-card {
    background-color: var(--light-gray);
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius);
    padding: var(--spacing-xl);
    margin-bottom: var(--spacing-large);
    box-shadow: var(--box-shadow);
}

.review-card.hidden {
    display: none;
}

.card-front,
.card-back {
    text-align: center;
}

.card-front p,
.card-back p {
    font-size: var(--font-size-large);
    margin-bottom: var(--spacing-large);
    min-height: 100px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.card-actions {
    display: flex;
    justify-content: center;
    gap: var(--spacing-medium);
    flex-wrap: wrap;
}

.card-actions button {
    min-width: 150px;
}

.progress {
    text-align: center;
    font-size: var(--font-size-medium);
    color: var(--dark-gray);
}

.progress.hidden {
    display: none;
}

/* Import/Export */
.import-export-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-xl);
    max-width: 800px;
    margin: 0 auto;
}

.export-section,
.import-section {
    background-color: var(--light-gray);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    padding: var(--spacing-large);
    box-shadow: var(--box-shadow);
}

.export-section h3,
.import-section h3 {
    color: var(--primary-color);
    margin-bottom: var(--spacing-medium);
}

/* Footer */
footer {
    background-color: var(--medium-gray);
    color: var(--dark-gray);
    text-align: center;
    padding: var(--spacing-large);
    border-top: 1px solid var(--border-color);
    margin-top: auto;
}

footer p {
    margin-bottom: var(--spacing-small);
    font-size: var(--font-size-small);
}

/* Responsive Design */
@media (max-width: 768px) {
    nav ul {
        flex-direction: column;
        align-items: center;
    }
    
    nav button {
        width: 100%;
        max-width: 300px;
    }
    
    .form-actions {
        flex-direction: column;
    }
    
    .form-actions button {
        width: 100%;
    }
    
    .boxes {
        grid-template-columns: 1fr;
    }
    
    .import-export-container {
        grid-template-columns: 1fr;
    }
}

/* Print Styles */
@media print {
    body {
        background: white;
        color: black;
    }
    
    .skip-link,
    nav,
    footer,
    button,
    .form-group,
    .form-actions,
    .import-export-container {
        display: none !important;
    }
    
    .section {
        display: block !important;
        page-break-inside: avoid;
    }
    
    .cards-grid {
        grid-template-columns: 1fr;
    }
}

/* High Contrast Mode for Windows */
@media (forced-colors: active) {
    button:focus,
    input:focus,
    textarea:focus,
    select:focus {
        forced-color-adjust: none;
        outline: 2px solid ButtonText !important;
    }
    
    .box-button:focus {
        outline: 2px solid ButtonText !important;
    }
}

/* Reduced Motion */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* Focus Visible for Keyboard Users */
:focus-visible {
    outline: var(--focus-outline);
    outline-offset: 2px;
}

/* Ensure sufficient color contrast */
button.primary {
    color: white;
    text-shadow: 1px 1px 1px rgba(0, 0, 0, 0.3);
}

button.secondary,
button.success,
button.error {
    color: white;
    text-shadow: 1px 1px 1px rgba(0, 0, 0, 0.3);
}

/* Larger text option for accessibility */
@media (prefers-contrast: high) {
    body {
        font-size: 1.1rem;
    }
}