/* ================================================
   CSS Reset / Normalize
   ================================================ */
*, *::before, *::after {
    box-sizing: border-box;
}

html, body, div, span, h1, h2, h3, h4, h5, h6, p, 
article, aside, footer, header, nav, section, 
button, input, select, textarea {
    margin: 0;
    padding: 0;
    border: 0;
    font-size: 100%;
    font: inherit;
    vertical-align: baseline;
}

article, aside, footer, header, nav, section {
    display: block;
}

body {
    line-height: 1;
}

button {
    cursor: pointer;
    background: none;
    border: none;
    font-family: inherit;
}

input, select, textarea {
    font-family: inherit;
}

/* ================================================
   CSS Custom Properties
   ================================================ */
:root {
    /* Colors */
    --color-primary: #2c3e50;
    --color-secondary: #3498db;
    --color-success: #27ae60;
    --color-warning: #f39c12;
    --color-danger: #e74c3c;
    --color-text: #333333;
    --color-text-light: #666666;
    --color-background: #ffffff;
    --color-background-alt: #f5f5f5;
    --color-border: #e0e0e0;
    
    /* Background Color Options */
    --bg-white: #ffffff;
    --bg-cream: #FFF8DC;
    --bg-light-green: #E8F5E9;
    --bg-light-blue: #E3F2FD;
    --bg-dark: #263238;
    
    /* Typography */
    --font-size-base: 16px;
    --font-size-small: 14px;
    --font-size-large: 18px;
    --font-size-xlarge: 24px;
    --font-size-xxlarge: 32px;
    --line-height-base: 1.8;
    --font-family-base: 'Hiragino Mincho ProN', 'Yu Mincho', 'MS PMincho', serif;
    --font-family-ui: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Hiragino Sans', sans-serif;
    
    /* Spacing */
    --spacing-xs: 4px;
    --spacing-sm: 8px;
    --spacing-md: 16px;
    --spacing-lg: 24px;
    --spacing-xl: 32px;
    --spacing-xxl: 48px;
    
    /* Layout */
    --header-height: 60px;
    --sidebar-width: 300px;
    --max-content-width: 1200px;
    
    /* Transitions */
    --transition-fast: 150ms ease-in-out;
    --transition-normal: 300ms ease-in-out;
    --transition-slow: 500ms ease-in-out;
    
    /* Shadows */
    --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 8px rgba(0, 0, 0, 0.15);
    --shadow-lg: 0 8px 16px rgba(0, 0, 0, 0.2);
    
    /* Border Radius */
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 16px;
}

/* Dark theme variables */
[data-theme="dark"] {
    --color-text: #f0f0f0;
    --color-text-light: #cccccc;
    --color-background: #263238;
    --color-background-alt: #37474f;
    --color-border: #455a64;
}

/* ================================================
   Base Typography
   ================================================ */
html {
    font-size: var(--font-size-base);
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family-ui);
    font-size: 1rem;
    line-height: var(--line-height-base);
    color: var(--color-text);
    background-color: var(--color-background);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    margin: 0;
    padding: 0;
    overflow: hidden;
    height: 100vh;
}

h1, h2, h3, h4, h5, h6 {
    font-weight: bold;
    line-height: 1.4;
    margin-bottom: var(--spacing-md);
}

h1 { font-size: 2rem; }
h2 { font-size: 1.75rem; }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }
h5 { font-size: 1.125rem; }
h6 { font-size: 1rem; }

p {
    margin-bottom: var(--spacing-md);
}

a {
    color: var(--color-secondary);
    text-decoration: none;
    transition: color var(--transition-fast);
}

a:hover {
    color: var(--color-primary);
}

/* ================================================
   Vertical Text Styles
   ================================================ */
.vertical-text {
    writing-mode: vertical-rl;
    text-orientation: mixed;
    direction: rtl;
    font-family: var(--font-family-base);
    line-height: var(--line-height-base);
    letter-spacing: 0.05em;
}

.vertical-text-container {
    writing-mode: vertical-rl;
    text-orientation: mixed;
    direction: rtl;
    font-family: var(--font-family-base);
    line-height: var(--line-height-base);
    letter-spacing: 0.05em;
    height: calc(100vh - var(--header-height) - 120px);
    overflow-x: auto;
    overflow-y: hidden;
    padding: var(--spacing-xl);
    background-color: var(--color-background);
}

/* Ruby text for readings */
ruby {
    ruby-align: center;
}

rt {
    font-size: 0.5em;
    font-weight: normal;
}

/* ================================================
   Layout Structure
   ================================================ */
.app-header {
    position: sticky;
    top: 0;
    z-index: 100;
    height: var(--header-height);
    background-color: var(--color-primary);
    color: white;
    box-shadow: var(--shadow-md);
}

.main-navigation {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 100%;
    padding: 0 var(--spacing-lg);
    max-width: var(--max-content-width);
    margin: 0 auto;
}

.app-title {
    font-size: 1.5rem;
    font-weight: bold;
    margin: 0;
}

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

.nav-btn {
    padding: var(--spacing-sm) var(--spacing-md);
    background-color: transparent;
    color: white;
    border: 2px solid transparent;
    border-radius: var(--radius-sm);
    transition: all var(--transition-fast);
    font-weight: 500;
}

.nav-btn:hover {
    background-color: rgba(255, 255, 255, 0.1);
    border-color: rgba(255, 255, 255, 0.3);
}

.nav-btn.active {
    background-color: rgba(255, 255, 255, 0.2);
    border-color: white;
}

.app-main {
    height: calc(100vh - var(--header-height));
    max-width: var(--max-content-width);
    margin: 0 auto;
    padding: 0;
    overflow: hidden;
    position: relative;
    margin-top: var(--header-height);
}

/* ================================================
   View Containers
   ================================================ */
.view-container {
    display: none;
    animation: fadeIn var(--transition-normal);
    height: 100%;
    overflow: auto;
}

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

/* 読書ビューは特別扱い */
#reading-view {
    overflow: hidden;
    position: relative;
}

#reading-view.active {
    display: block;
}

.view-title {
    margin-bottom: var(--spacing-xl);
    color: var(--color-primary);
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

/* ================================================
   Library View Styles
   ================================================ */
.search-filter-container {
    margin-bottom: var(--spacing-xl);
    background-color: var(--color-background-alt);
    padding: var(--spacing-lg);
    border-radius: var(--radius-md);
}

.search-bar {
    width: 100%;
    padding: var(--spacing-md);
    font-size: 1rem;
    border: 2px solid var(--color-border);
    border-radius: var(--radius-sm);
    margin-bottom: var(--spacing-md);
    transition: border-color var(--transition-fast);
}

.search-bar:focus {
    outline: none;
    border-color: var(--color-secondary);
}

.filter-controls {
    display: flex;
    gap: var(--spacing-md);
    flex-wrap: wrap;
}

.filter-dropdown {
    flex: 1;
    min-width: 150px;
    padding: var(--spacing-sm) var(--spacing-md);
    border: 2px solid var(--color-border);
    border-radius: var(--radius-sm);
    background-color: white;
    font-size: 1rem;
    transition: border-color var(--transition-fast);
}

.filter-dropdown:focus {
    outline: none;
    border-color: var(--color-secondary);
}

.books-container {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: var(--spacing-lg);
}

/* ================================================
   Book Card Styles
   ================================================ */
.book-card {
    background-color: white;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    padding: var(--spacing-lg);
    transition: all var(--transition-normal);
    cursor: pointer;
    box-shadow: var(--shadow-sm);
}

.book-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
    border-color: var(--color-secondary);
}

.book-card-title {
    font-size: 1.25rem;
    font-weight: bold;
    margin-bottom: var(--spacing-sm);
    color: var(--color-primary);
}

.book-card-author {
    color: var(--color-text-light);
    margin-bottom: var(--spacing-md);
}

.book-card-meta {
    display: flex;
    gap: var(--spacing-md);
    font-size: var(--font-size-small);
    color: var(--color-text-light);
}

.difficulty-badge {
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--radius-sm);
    font-weight: 500;
}

.difficulty-beginner {
    background-color: #e8f5e9;
    color: #2e7d32;
}

.difficulty-intermediate {
    background-color: #fff3e0;
    color: #ef6c00;
}

.difficulty-advanced {
    background-color: #ffebee;
    color: #c62828;
}

/* ================================================
   Reading View Styles
   ================================================ */
.reading-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: var(--spacing-lg);
    padding: var(--spacing-md);
    background-color: var(--color-background-alt);
    border-radius: var(--radius-md);
}

.back-to-library {
    padding: var(--spacing-sm) var(--spacing-md);
    background-color: white;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    transition: all var(--transition-fast);
}

.back-to-library:hover {
    background-color: var(--color-primary);
    color: white;
}

.book-title {
    font-size: 1.5rem;
    font-weight: bold;
    margin: 0;
}

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

.progress-bar {
    width: 200px;
    height: 8px;
    background-color: var(--color-border);
    border-radius: 4px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background-color: var(--color-success);
    width: 0%;
    transition: width var(--transition-normal);
}

.progress-text {
    font-size: var(--font-size-small);
    font-weight: 500;
}

.reading-navigation {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-lg);
    margin-top: var(--spacing-lg);
    padding: var(--spacing-md);
    background-color: var(--color-background-alt);
    border-radius: var(--radius-md);
}

.page-nav-btn {
    padding: var(--spacing-sm) var(--spacing-lg);
    background-color: var(--color-primary);
    color: white;
    border-radius: var(--radius-sm);
    transition: all var(--transition-fast);
    font-weight: 500;
}

.page-nav-btn:hover:not(:disabled) {
    background-color: var(--color-secondary);
}

.page-nav-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.page-indicator {
    font-weight: 500;
}

/* ================================================
   Dictionary Popup Styles
   ================================================ */
.popup {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    transition: opacity var(--transition-fast);
}

.popup.hidden {
    display: none;
}

.popup-content {
    background-color: white;
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
    max-width: 500px;
    width: 90%;
    box-shadow: var(--shadow-lg);
    position: relative;
}

.popup-close {
    position: absolute;
    top: var(--spacing-md);
    right: var(--spacing-md);
    font-size: 1.5rem;
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    transition: background-color var(--transition-fast);
}

.popup-close:hover {
    background-color: var(--color-background-alt);
}

.word-title {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-sm);
}

.word-reading {
    font-size: 1.125rem;
    color: var(--color-text-light);
    margin-bottom: var(--spacing-md);
}

.word-definition {
    line-height: 1.6;
}

/* ================================================
   Progress View Styles
   ================================================ */
.progress-summary {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-xl);
}

.stat-card {
    background-color: white;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    padding: var(--spacing-lg);
    text-align: center;
    box-shadow: var(--shadow-sm);
}

.stat-card h3 {
    font-size: 1rem;
    color: var(--color-text-light);
    margin-bottom: var(--spacing-md);
}

.stat-value {
    font-size: 2rem;
    font-weight: bold;
    color: var(--color-primary);
}

.achievements-section {
    margin-top: var(--spacing-xxl);
}

.achievements-container {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
    gap: var(--spacing-md);
}

/* ================================================
   Settings View Styles
   ================================================ */
.settings-group {
    background-color: white;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    padding: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
}

.settings-group h3 {
    margin-bottom: var(--spacing-lg);
    padding-bottom: var(--spacing-md);
    border-bottom: 1px solid var(--color-border);
}

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

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

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

input[type="range"] {
    width: 100%;
    margin-bottom: var(--spacing-sm);
}

.color-options {
    display: flex;
    gap: var(--spacing-md);
}

.color-option {
    width: 40px;
    height: 40px;
    border: 2px solid var(--color-border);
    border-radius: var(--radius-sm);
    transition: all var(--transition-fast);
}

.color-option:hover {
    transform: scale(1.1);
}

.color-option.active {
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px rgba(44, 62, 80, 0.2);
}

.danger-button {
    padding: var(--spacing-sm) var(--spacing-lg);
    background-color: var(--color-danger);
    color: white;
    border-radius: var(--radius-sm);
    transition: all var(--transition-fast);
    font-weight: 500;
}

.danger-button:hover {
    background-color: #c0392b;
}

/* ================================================
   Loading Overlay
   ================================================ */
.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(255, 255, 255, 0.9);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    z-index: 2000;
}

.loading-spinner {
    width: 50px;
    height: 50px;
    border: 4px solid var(--color-border);
    border-top-color: var(--color-primary);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin-bottom: var(--spacing-md);
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.loading-text {
    font-size: 1.125rem;
    color: var(--color-text-light);
}

/* ================================================
   Notification Styles
   ================================================ */
.notification {
    position: fixed;
    top: calc(var(--header-height) + var(--spacing-lg));
    right: var(--spacing-lg);
    background-color: var(--color-success);
    color: white;
    padding: var(--spacing-lg);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-lg);
    transform: translateX(400px);
    transition: transform var(--transition-normal);
    z-index: 1500;
}

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

.notification h3 {
    margin-bottom: var(--spacing-sm);
    font-size: 1.125rem;
}

.achievement-name {
    font-size: 1rem;
}

/* Point Notification */
.point-notification {
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%) scale(0);
    background: linear-gradient(135deg, var(--color-warning), #f1c40f);
    color: white;
    padding: var(--spacing-lg) var(--spacing-xl);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    z-index: 1600;
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    opacity: 0;
    transition: all var(--transition-normal);
}

.point-notification.show {
    transform: translate(-50%, -50%) scale(1);
    opacity: 1;
}

.point-icon {
    font-size: 2rem;
    animation: sparkle 1s ease-in-out infinite;
}

.point-text {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.point-text strong {
    font-size: 1.25rem;
    font-weight: bold;
}

.point-text span {
    font-size: 0.875rem;
    opacity: 0.9;
}

@keyframes sparkle {
    0%, 100% { transform: scale(1) rotate(0deg); }
    50% { transform: scale(1.2) rotate(180deg); }
}

/* Achievement Notification */
#achievement-notification {
    position: fixed;
    top: calc(var(--header-height) + var(--spacing-lg));
    left: 50%;
    transform: translateX(-50%) translateY(-100px);
    background: linear-gradient(135deg, #8e44ad, #9b59b6);
    color: white;
    padding: var(--spacing-xl);
    border-radius: var(--radius-lg);
    box-shadow: 0 10px 30px rgba(142, 68, 173, 0.4);
    z-index: 1700;
    text-align: center;
    min-width: 300px;
    opacity: 0;
    transition: all var(--transition-normal);
}

#achievement-notification.show {
    transform: translateX(-50%) translateY(0);
    opacity: 1;
}

#achievement-notification::before {
    content: '🏆';
    display: block;
    font-size: 3rem;
    margin-bottom: var(--spacing-md);
    animation: bounce 1s ease-in-out;
}

@keyframes bounce {
    0%, 100% { transform: translateY(0); }
    25% { transform: translateY(-10px); }
    75% { transform: translateY(5px); }
}

/* Completion Certificate Modal */
.completion-certificate {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.8);
    z-index: 2000;
    display: flex;
    align-items: center;
    justify-content: center;
    animation: fadeIn var(--transition-normal);
}

.certificate-modal-content {
    background: var(--color-background);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    max-width: 900px;
    width: 90%;
    max-height: 90vh;
    overflow: auto;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.3);
    animation: slideUp var(--transition-normal);
}

.certificate-canvas-container {
    display: flex;
    justify-content: center;
    align-items: center;
    margin-bottom: var(--spacing-lg);
    background: var(--color-background-alt);
    border-radius: var(--radius-md);
    padding: var(--spacing-md);
}

.certificate-canvas-container canvas {
    max-width: 100%;
    height: auto;
    border-radius: var(--radius-sm);
    box-shadow: var(--shadow-md);
}

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

.certificate-actions button {
    padding: var(--spacing-md) var(--spacing-xl);
    border-radius: var(--radius-md);
    font-size: 1rem;
    font-weight: bold;
    transition: all var(--transition-fast);
    cursor: pointer;
    border: none;
}

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

.btn-download-png:hover {
    background-color: #2980b9;
    transform: translateY(-2px);
}

.btn-download-pdf {
    background-color: var(--color-danger);
    color: white;
}

.btn-download-pdf:hover {
    background-color: #c0392b;
    transform: translateY(-2px);
}

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

.btn-print:hover {
    background-color: #229954;
    transform: translateY(-2px);
}

.btn-close {
    background-color: var(--color-text-light);
    color: white;
}

.btn-close:hover {
    background-color: var(--color-text);
    transform: translateY(-2px);
}

/* Old certificate content (for backwards compatibility) */
.certificate-content {
    background: linear-gradient(to bottom, #fff, #f9f9f9);
    border: 3px solid var(--color-warning);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xxl);
    max-width: 500px;
    width: 90%;
    text-align: center;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.3);
    position: relative;
    animation: slideUp var(--transition-normal);
}

.certificate-content::before,
.certificate-content::after {
    content: '';
    position: absolute;
    width: 100px;
    height: 100px;
    background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><path d="M50 10 L60 40 L90 40 L65 60 L75 90 L50 70 L25 90 L35 60 L10 40 L40 40 Z" fill="%23f39c12"/></svg>') no-repeat center;
    background-size: contain;
}

.certificate-content::before {
    top: -50px;
    left: -50px;
}

.certificate-content::after {
    bottom: -50px;
    right: -50px;
}

.certificate-content h2 {
    color: var(--color-primary);
    font-size: 2rem;
    margin-bottom: var(--spacing-lg);
    font-family: var(--font-family-base);
}

.certificate-icon {
    font-size: 4rem;
    margin: var(--spacing-lg) 0;
    animation: pulse 2s ease-in-out infinite;
}

.certificate-content p {
    margin-bottom: var(--spacing-md);
    color: var(--color-text);
    line-height: 1.6;
}

.certificate-content strong {
    color: var(--color-primary);
    font-size: 1.2em;
}

.close-certificate {
    margin-top: var(--spacing-xl);
    padding: var(--spacing-md) var(--spacing-xl);
    background-color: var(--color-primary);
    color: white;
    border-radius: var(--radius-md);
    font-size: 1rem;
    transition: all var(--transition-fast);
    cursor: pointer;
}

.close-certificate:hover {
    background-color: var(--color-secondary);
    transform: scale(1.05);
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

@keyframes slideUp {
    from { transform: translateY(50px); opacity: 0; }
    to { transform: translateY(0); opacity: 1; }
}

@keyframes pulse {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.1); }
}

/* Progress Indicators */
.chapter-progress {
    display: flex;
    gap: var(--spacing-sm);
    align-items: center;
    margin: var(--spacing-md) 0;
    flex-wrap: wrap;
}

.chapter-indicator {
    width: 30px;
    height: 30px;
    border-radius: 50%;
    background-color: var(--color-border);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.75rem;
    color: var(--color-text-light);
    transition: all var(--transition-fast);
    position: relative;
}

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

.chapter-indicator.current {
    background-color: var(--color-secondary);
    color: white;
    animation: pulse 2s ease-in-out infinite;
}

.chapter-indicator.completed::after {
    content: '✓';
    position: absolute;
    color: white;
    font-weight: bold;
}

/* Reading Time Display */
.reading-time-display {
    background-color: var(--color-background-alt);
    border-radius: var(--radius-md);
    padding: var(--spacing-lg);
    margin: var(--spacing-md) 0;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: var(--spacing-md);
}

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

.time-stat h4 {
    font-size: 0.875rem;
    color: var(--color-text-light);
    margin-bottom: var(--spacing-sm);
}

.time-value {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--color-primary);
}

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

/* ================================================
   Statistics Section
   ================================================ */
.statistics-section {
    margin-top: var(--spacing-xxl);
    padding: var(--spacing-xl);
    background-color: var(--color-background-alt);
    border-radius: var(--radius-lg);
}

.statistics-section h3 {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-lg);
    color: var(--color-primary);
}

/* Tab Navigation */
.stats-tabs {
    display: flex;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-lg);
    border-bottom: 2px solid var(--color-border);
}

.stats-tab {
    padding: var(--spacing-md) var(--spacing-lg);
    background: none;
    border: none;
    color: var(--color-text-light);
    font-size: 1rem;
    cursor: pointer;
    position: relative;
    transition: all var(--transition-fast);
}

.stats-tab:hover {
    color: var(--color-primary);
}

.stats-tab.active {
    color: var(--color-primary);
    font-weight: bold;
}

.stats-tab.active::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    right: 0;
    height: 2px;
    background-color: var(--color-primary);
}

/* Tab Content */
.stats-content {
    background-color: var(--color-background);
    border-radius: var(--radius-md);
    padding: var(--spacing-lg);
    min-height: 400px;
}

.stats-panel {
    display: none;
}

.stats-panel.active {
    display: block;
}

/* Chart Container */
.chart-container {
    position: relative;
    height: 300px;
    margin-bottom: var(--spacing-lg);
}

.chart-container h4 {
    text-align: center;
    margin-bottom: var(--spacing-md);
    color: var(--color-text);
}

/* Stats Controls */
.stats-controls {
    display: flex;
    justify-content: center;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-lg);
}

.period-btn {
    padding: var(--spacing-sm) var(--spacing-md);
    border: 1px solid var(--color-border);
    background-color: var(--color-background);
    border-radius: var(--radius-sm);
    color: var(--color-text);
    cursor: pointer;
    transition: all var(--transition-fast);
}

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

.period-btn.active {
    background-color: var(--color-primary);
    color: white;
    border-color: var(--color-primary);
}

/* Learning Stats */
.learning-stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: var(--spacing-md);
    margin-top: var(--spacing-lg);
}

.stat-item {
    text-align: center;
    padding: var(--spacing-md);
    background-color: var(--color-background-alt);
    border-radius: var(--radius-md);
}

.stat-item h4 {
    font-size: 0.875rem;
    color: var(--color-text-light);
    margin-bottom: var(--spacing-sm);
}

.stat-item p {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--color-primary);
}

/* Genre Recommendations */
.genre-recommendations {
    margin-top: var(--spacing-lg);
}

.genre-recommendations h4 {
    margin-bottom: var(--spacing-md);
    color: var(--color-text);
}

#recommended-books {
    display: grid;
    gap: var(--spacing-md);
}

.recommended-book {
    padding: var(--spacing-md);
    background-color: var(--color-background-alt);
    border-radius: var(--radius-md);
    border-left: 3px solid var(--color-secondary);
}

.recommended-book h5 {
    font-size: 1rem;
    margin-bottom: var(--spacing-xs);
    color: var(--color-primary);
}

.book-author {
    font-size: 0.875rem;
    color: var(--color-text-light);
    margin-bottom: var(--spacing-xs);
}

.recommendation-reason {
    font-size: 0.75rem;
    color: var(--color-text-light);
    font-style: italic;
}

/* Trends Grid */
.trends-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
}

/* Reading Insights */
.reading-insights {
    padding: var(--spacing-lg);
    background-color: var(--color-background-alt);
    border-radius: var(--radius-md);
}

.reading-insights h4 {
    margin-bottom: var(--spacing-md);
    color: var(--color-text);
}

#insights-list {
    list-style: none;
    padding: 0;
}

#insights-list li {
    padding: var(--spacing-sm) 0;
    color: var(--color-text);
    line-height: 1.6;
}

/* Export Controls */
.stats-export {
    display: flex;
    justify-content: center;
    gap: var(--spacing-md);
    margin-top: var(--spacing-lg);
    padding-top: var(--spacing-lg);
    border-top: 1px solid var(--color-border);
}

.stats-export button {
    padding: var(--spacing-md) var(--spacing-lg);
    border: none;
    border-radius: var(--radius-md);
    font-size: 1rem;
    cursor: pointer;
    transition: all var(--transition-fast);
}

#export-csv {
    background-color: var(--color-success);
    color: white;
}

#export-csv:hover {
    background-color: #229954;
    transform: translateY(-2px);
}

#export-image {
    background-color: var(--color-secondary);
    color: white;
}

#export-image:hover {
    background-color: #2980b9;
    transform: translateY(-2px);
}

/* Responsive Statistics */
@media screen and (max-width: 768px) {
    .stats-tabs {
        overflow-x: auto;
        -webkit-overflow-scrolling: touch;
    }
    
    .trends-grid {
        grid-template-columns: 1fr;
    }
    
    .stats-export {
        flex-direction: column;
    }
    
    .stats-export button {
        width: 100%;
    }
}

/* ================================================
   Utility Classes
   ================================================ */
.hidden {
    display: none !important;
}

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

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

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

/* ================================================
   Responsive Design
   ================================================ */
@media screen and (max-width: 768px) {
    :root {
        --font-size-base: 14px;
    }
    
    .app-title {
        font-size: 1.25rem;
    }
    
    .nav-buttons {
        gap: var(--spacing-sm);
    }
    
    .nav-btn {
        padding: var(--spacing-xs) var(--spacing-sm);
        font-size: 0.875rem;
    }
    
    .app-main {
        padding: var(--spacing-md);
    }
    
    .books-container {
        grid-template-columns: 1fr;
    }
    
    .filter-controls {
        flex-direction: column;
    }
    
    .filter-dropdown {
        width: 100%;
    }
    
    .reading-header {
        flex-direction: column;
        gap: var(--spacing-md);
        align-items: flex-start;
    }
    
    .progress-bar {
        width: 100%;
    }
    
    .vertical-text-container {
        height: calc(100vh - var(--header-height) - 100px);
        padding: var(--spacing-md);
    }
}

@media screen and (max-width: 480px) {
    .progress-summary {
        grid-template-columns: 1fr;
    }
    
    .reading-navigation {
        flex-wrap: wrap;
    }
    
    .page-nav-btn {
        flex: 1;
        min-width: 100px;
    }
}

/* ================================================
   Print Styles
   ================================================ */
@media print {
    .app-header,
    .reading-navigation,
    .back-to-library,
    .nav-buttons {
        display: none;
    }
    
    .vertical-text-container {
        height: auto;
        overflow: visible;
        padding: 0;
    }
    
    body {
        background-color: white;
        color: black;
    }
}

/* ================================================
   Parent Dashboard Styles
   ================================================ */

/* 保護者ダッシュボード */
.parent-dashboard {
    padding: 20px;
    background-color: var(--background-color);
}

.parent-dashboard h2 {
    color: var(--primary-color);
    margin-bottom: 20px;
    font-size: 24px;
}

/* ダッシュボードタブ */
.dashboard-tabs {
    display: flex;
    gap: 10px;
    margin-bottom: 20px;
    border-bottom: 2px solid #e0e0e0;
    overflow-x: auto;
}

.tab-button {
    padding: 10px 20px;
    background: none;
    border: none;
    cursor: pointer;
    font-size: 16px;
    color: #666;
    transition: all 0.3s ease;
    white-space: nowrap;
    position: relative;
}

.tab-button.active {
    color: var(--primary-color);
}

.tab-button.active::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    right: 0;
    height: 2px;
    background-color: var(--primary-color);
}

/* パネル */
.dashboard-content {
    background: white;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    padding: 20px;
    min-height: 400px;
}

.panel {
    display: none;
}

.panel.active {
    display: block;
}

/* 概要統計 */
.overview-stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin-bottom: 30px;
}

.stat-card {
    background: #f8f9fa;
    padding: 20px;
    border-radius: 8px;
    text-align: center;
}

.stat-card h3 {
    font-size: 14px;
    color: #666;
    margin-bottom: 10px;
}

.stat-value {
    font-size: 32px;
    font-weight: bold;
    color: var(--primary-color);
    margin-bottom: 5px;
}

.stat-subtitle {
    font-size: 14px;
    color: #999;
}

.stat-trend {
    font-size: 14px;
    color: #28a745;
}

/* アクティビティリスト */
.recent-activity {
    margin-top: 30px;
}

.recent-activity h3 {
    font-size: 18px;
    margin-bottom: 15px;
}

.activity-list {
    list-style: none;
}

.activity-item {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 10px 0;
    border-bottom: 1px solid #f0f0f0;
}

.activity-icon {
    font-size: 20px;
}

.activity-text {
    flex: 1;
}

.activity-time {
    font-size: 12px;
    color: #999;
}

/* 読書時間統計 */
.time-stats-container {
    padding: 20px;
}

.period-selector {
    display: flex;
    gap: 10px;
    margin-bottom: 20px;
}

.period-btn {
    padding: 8px 16px;
    border: 1px solid #ddd;
    background: white;
    cursor: pointer;
    border-radius: 4px;
    transition: all 0.3s ease;
}

.period-btn.active {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

.time-chart-container {
    height: 300px;
    margin-bottom: 30px;
}

.time-summary {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 20px;
    margin-bottom: 30px;
}

.summary-item h4 {
    font-size: 14px;
    color: #666;
    margin-bottom: 5px;
}

.summary-item p {
    font-size: 24px;
    font-weight: bold;
    color: var(--primary-color);
}

/* 読書目標 */
.reading-goals {
    background: #f8f9fa;
    padding: 20px;
    border-radius: 8px;
}

.goal-item {
    display: flex;
    align-items: center;
    gap: 15px;
    margin-bottom: 15px;
}

.goal-progress {
    flex: 1;
    height: 20px;
    background: #e0e0e0;
    border-radius: 10px;
    overflow: hidden;
}

.goal-bar {
    height: 100%;
    background: var(--success-color);
    transition: width 0.3s ease;
}

/* 語彙統計 */
.vocabulary-container {
    padding: 20px;
}

.vocab-overview {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 20px;
    margin-bottom: 30px;
}

.vocab-stat h4 {
    font-size: 14px;
    color: #666;
    margin-bottom: 5px;
}

.vocab-number {
    font-size: 28px;
    font-weight: bold;
    color: var(--primary-color);
}

/* 語彙レベル分布 */
.vocab-level-distribution {
    margin-bottom: 30px;
}

.level-bars {
    margin-top: 15px;
}

.level-bar-item {
    display: flex;
    align-items: center;
    gap: 15px;
    margin-bottom: 10px;
}

.level-label {
    width: 60px;
    font-size: 14px;
}

.level-bar {
    flex: 1;
    height: 20px;
    background: #e0e0e0;
    border-radius: 10px;
    overflow: hidden;
}

.level-fill {
    height: 100%;
    transition: width 0.3s ease;
}

.level-fill.beginner {
    background: #28a745;
}

.level-fill.intermediate {
    background: #ffc107;
}

.level-fill.advanced {
    background: #dc3545;
}

.level-count {
    width: 40px;
    text-align: right;
    font-size: 14px;
}

/* 最近の語彙 */
.word-list {
    margin-top: 15px;
}

.word-item {
    display: flex;
    align-items: center;
    gap: 15px;
    padding: 10px;
    background: #f8f9fa;
    border-radius: 4px;
    margin-bottom: 10px;
}

.word-text {
    font-size: 18px;
    font-weight: bold;
}

.word-reading {
    font-size: 14px;
    color: #666;
}

.word-date {
    margin-left: auto;
    font-size: 12px;
    color: #999;
}

/* 復習推奨語彙 */
.review-words {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-top: 10px;
}

.review-word {
    padding: 5px 15px;
    background: #e3f2fd;
    border-radius: 20px;
    font-size: 14px;
}

/* アチーブメント */
.achievements-container {
    padding: 20px;
}

.achievement-stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 20px;
    margin-bottom: 30px;
}

.achievement-stat h4 {
    font-size: 14px;
    color: #666;
    margin-bottom: 5px;
}

.achievement-stat p {
    font-size: 24px;
    font-weight: bold;
    color: var(--primary-color);
}

/* バッジ */
.badges {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
    gap: 15px;
    margin-top: 15px;
}

.badge-item {
    text-align: center;
    padding: 20px;
    border-radius: 8px;
    background: #f8f9fa;
    transition: transform 0.3s ease;
}

.badge-item:hover {
    transform: translateY(-5px);
}

.badge-item.earned {
    background: #e8f5e9;
}

.badge-item.upcoming {
    opacity: 0.7;
}

.badge-icon {
    font-size: 40px;
    margin-bottom: 10px;
}

.badge-name {
    font-size: 14px;
    font-weight: bold;
    margin-bottom: 5px;
}

.badge-date {
    font-size: 12px;
    color: #666;
}

.badge-progress {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-top: 10px;
}

.badge-progress .progress-bar {
    flex: 1;
    height: 10px;
    background: #e0e0e0;
    border-radius: 5px;
    overflow: hidden;
}

.badge-progress .progress-fill {
    height: 100%;
    background: var(--primary-color);
}

/* 推奨事項 */
.recommendations-container {
    padding: 20px;
}

.reading-analysis {
    background: #f8f9fa;
    padding: 20px;
    border-radius: 8px;
    margin-bottom: 30px;
}

.analysis-item {
    display: flex;
    justify-content: space-between;
    padding: 10px 0;
    border-bottom: 1px solid #e0e0e0;
}

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

.analysis-label {
    font-weight: bold;
}

.analysis-value {
    color: var(--primary-color);
}

/* おすすめ作品 */
.recommended-books {
    margin-top: 15px;
}

.book-recommendation {
    padding: 15px;
    background: #f8f9fa;
    border-radius: 8px;
    margin-bottom: 15px;
}

.book-recommendation h5 {
    font-size: 16px;
    margin-bottom: 5px;
}

.book-author {
    font-size: 14px;
    color: #666;
    margin-bottom: 5px;
}

.book-reason {
    font-size: 14px;
    margin-bottom: 10px;
}

.book-difficulty {
    font-size: 14px;
}

.difficulty-beginner {
    color: #28a745;
}

.difficulty-intermediate {
    color: #ffc107;
}

.difficulty-advanced {
    color: #dc3545;
}

/* 習慣提案 */
.suggestion-list {
    list-style: none;
    margin-top: 15px;
}

.suggestion-item {
    display: flex;
    align-items: flex-start;
    gap: 10px;
    padding: 10px 0;
    border-bottom: 1px solid #f0f0f0;
}

.suggestion-item i {
    color: #ffc107;
    margin-top: 2px;
}

/* ダッシュボードアクション */
.dashboard-actions {
    display: flex;
    gap: 10px;
    margin-top: 20px;
    padding-top: 20px;
    border-top: 1px solid #e0e0e0;
}

.action-button {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 10px 20px;
    border: 1px solid var(--primary-color);
    background: white;
    color: var(--primary-color);
    border-radius: 4px;
    cursor: pointer;
    transition: all 0.3s ease;
}

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

.action-button i {
    font-size: 16px;
}

/* レスポンシブ対応（保護者ダッシュボード） */
@media (max-width: 768px) {
    .dashboard-tabs {
        -webkit-overflow-scrolling: touch;
    }
    
    .overview-stats {
        grid-template-columns: 1fr 1fr;
    }
    
    .time-summary {
        grid-template-columns: 1fr 1fr;
    }
    
    .dashboard-actions {
        flex-direction: column;
    }
    
    .action-button {
        width: 100%;
        justify-content: center;
    }
}

/* ================================================
   Enhanced Responsive Design
   ================================================ */

/* モバイルファースト設計 */

/* Extra Small Devices (320px-479px) */
@media screen and (max-width: 479px) {
    /* ヘッダー調整 */
    .app-header {
        padding: 10px;
    }
    
    .app-title {
        font-size: 16px;
        text-align: center;
    }
    
    .nav-buttons {
        flex-wrap: wrap;
        gap: 5px;
    }
    
    .nav-btn {
        font-size: 12px;
        padding: 8px 12px;
        flex: 1 1 45%;
    }
    
    /* 作品カード */
    .book-grid {
        grid-template-columns: 1fr;
        gap: 15px;
    }
    
    .book-card {
        min-height: 120px;
    }
    
    /* 縦書きテキスト */
    .vertical-text-container {
        font-size: 14px;
        line-height: 1.6;
        padding: 10px;
    }
    
    /* モーダル */
    .modal-content {
        width: 100%;
        height: 100%;
        margin: 0;
        border-radius: 0;
    }
    
    /* 通知 */
    .notification-container {
        left: 10px;
        right: 10px;
        top: 60px;
    }
    
    .notification-item {
        width: 100%;
    }
}

/* Small Devices (480px-767px) */
@media screen and (min-width: 480px) and (max-width: 767px) {
    /* ヘッダー */
    .app-header {
        padding: 15px;
    }
    
    .app-title {
        font-size: 18px;
    }
    
    .nav-buttons {
        gap: 10px;
    }
    
    .nav-btn {
        font-size: 14px;
        padding: 8px 16px;
    }
    
    /* 作品グリッド */
    .book-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 20px;
    }
    
    /* 縦書きテキスト */
    .vertical-text-container {
        font-size: 16px;
        padding: 20px;
    }
    
    /* フィルター */
    .search-filter-container {
        flex-direction: column;
        gap: 10px;
    }
    
    .search-bar {
        width: 100%;
    }
    
    .filter-controls {
        width: 100%;
        flex-wrap: wrap;
    }
}

/* Medium Devices / Tablets (768px-1023px) */
@media screen and (min-width: 768px) and (max-width: 1023px) {
    /* コンテナ幅 */
    .app-main {
        max-width: 100%;
        padding: 20px;
    }
    
    /* 作品グリッド */
    .book-grid {
        grid-template-columns: repeat(3, 1fr);
        gap: 25px;
    }
    
    /* 縦書きテキスト */
    .vertical-text-container {
        font-size: 18px;
        max-width: 90%;
        margin: 0 auto;
    }
    
    /* ナビゲーション */
    .reading-navigation {
        position: fixed;
        bottom: 20px;
        left: 50%;
        transform: translateX(-50%);
        background: rgba(255, 255, 255, 0.95);
        padding: 15px;
        border-radius: 30px;
        box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
    }
    
    /* サイドバー表示準備 */
    .sidebar-ready {
        display: flex;
    }
    
    .main-content {
        flex: 1;
    }
    
    .sidebar {
        width: 300px;
        display: none; /* 将来的に有効化 */
    }
}

/* Large Devices / Desktop (1024px以上) */
@media screen and (min-width: 1024px) {
    /* コンテナ最大幅 */
    .app-main {
        max-width: 1400px;
        margin: 0 auto;
        padding: 30px;
    }
    
    /* 作品グリッド */
    .book-grid {
        grid-template-columns: repeat(4, 1fr);
        gap: 30px;
    }
    
    /* 縦書きテキスト最適化 */
    .vertical-text-container {
        font-size: 20px;
        max-width: 800px;
        margin: 0 auto;
        column-count: 2;
        column-gap: 40px;
    }
    
    /* ホバーエフェクトの有効化 */
    .book-card:hover {
        transform: translateY(-5px);
        box-shadow: 0 10px 30px rgba(0, 0, 0, 0.15);
    }
    
    .nav-btn:hover {
        background-color: var(--primary-color);
        color: white;
    }
    
    /* デスクトップ向けレイアウト */
    .desktop-layout {
        display: grid;
        grid-template-columns: 250px 1fr 300px;
        gap: 30px;
    }
}

/* 高解像度ディスプレイ対応 */
@media screen and (-webkit-min-device-pixel-ratio: 2),
       screen and (min-resolution: 192dpi) {
    /* 高解像度画像の使用 */
    .book-card {
        background-image: url('images/book-bg@2x.png');
    }
    
    /* ボーダーの細線化 */
    .book-card,
    .modal-content,
    .notification-item {
        border-width: 0.5px;
    }
}

/* 横向きモバイル対応 */
@media screen and (max-width: 767px) and (orientation: landscape) {
    /* ヘッダーの縮小 */
    .app-header {
        padding: 5px 15px;
    }
    
    .app-title {
        font-size: 16px;
    }
    
    /* コンテンツエリアの調整 */
    .view-container {
        padding-top: 60px;
        height: calc(100vh - 60px);
    }
    
    /* 縦書きテキストの調整 */
    .vertical-text-container {
        height: calc(100vh - 80px);
        columns: 2;
    }
}

/* ダークモード対応準備 */
@media (prefers-color-scheme: dark) {
    /* 将来的なダークモード実装用 */
    .dark-mode-ready {
        --bg-color: #1a1a1a;
        --text-color: #e0e0e0;
    }
}

/* 印刷用スタイルの拡張 */
@media print {
    /* ページ設定 */
    @page {
        size: A4;
        margin: 2cm;
    }
    
    /* 不要要素の非表示 */
    .app-header,
    .nav-buttons,
    .reading-navigation,
    .filter-controls,
    .notification-container,
    .modal-overlay {
        display: none !important;
    }
    
    /* 印刷用レイアウト */
    .vertical-text-container {
        height: auto !important;
        overflow: visible !important;
        columns: 1 !important;
        writing-mode: horizontal-tb !important; /* 印刷時は横書き */
    }
    
    /* ページブレイク制御 */
    .chapter-title {
        page-break-before: always;
    }
    
    h1, h2, h3 {
        page-break-after: avoid;
    }
    
    p {
        orphans: 3;
        widows: 3;
    }
}

/* アニメーション無効化（アクセシビリティ） */
@media (prefers-reduced-motion: reduce) {
    * {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
    
    .book-card:hover {
        transform: none;
    }
    
    .notification-item {
        animation: none;
    }
}

/* タッチデバイス向け調整 */
@media (hover: none) and (pointer: coarse) {
    /* タッチターゲットの拡大 */
    button,
    a,
    .clickable {
        min-height: 44px;
        min-width: 44px;
    }
    
    /* ホバーエフェクトの無効化 */
    .book-card:hover {
        transform: none;
    }
    
    /* タッチフィードバック */
    .touchable {
        -webkit-tap-highlight-color: rgba(0, 0, 0, 0.1);
    }
}

/* スクロールバーのカスタマイズ */
@media screen and (min-width: 768px) {
    /* Webkit browsers */
    ::-webkit-scrollbar {
        width: 10px;
        height: 10px;
    }
    
    ::-webkit-scrollbar-track {
        background: #f1f1f1;
        border-radius: 5px;
    }
    
    ::-webkit-scrollbar-thumb {
        background: var(--primary-color);
        border-radius: 5px;
        opacity: 0.7;
    }
    
    ::-webkit-scrollbar-thumb:hover {
        opacity: 1;
    }
    
    /* Firefox */
    * {
        scrollbar-width: thin;
        scrollbar-color: var(--primary-color) #f1f1f1;
    }
}

/* エラー表示用スタイル */
.error-toast-container {
    position: fixed;
    top: 20px;
    right: 20px;
    z-index: 10000;
    display: flex;
    flex-direction: column;
    gap: 10px;
    pointer-events: none;
}

.error-toast {
    background: white;
    border-radius: 8px;
    padding: 16px 20px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
    display: flex;
    align-items: center;
    gap: 12px;
    min-width: 300px;
    max-width: 500px;
    pointer-events: auto;
    opacity: 0;
    transform: translateX(100%);
    transition: all 0.3s ease;
}

.error-toast-show {
    opacity: 1;
    transform: translateX(0);
}

.error-toast-hide {
    opacity: 0;
    transform: translateX(100%);
}

.error-toast-error {
    border-left: 4px solid #f44336;
}

.error-toast-warning {
    border-left: 4px solid #ff9800;
}

.error-toast-info {
    border-left: 4px solid #2196f3;
}

.error-toast-icon {
    font-size: 20px;
    flex-shrink: 0;
}

.error-toast-message {
    flex: 1;
    font-size: 14px;
    line-height: 1.5;
    color: var(--text-primary);
}

.error-toast-close {
    background: none;
    border: none;
    padding: 4px;
    cursor: pointer;
    font-size: 16px;
    color: #666;
    flex-shrink: 0;
    transition: color 0.2s;
}

.error-toast-close:hover {
    color: #333;
}

/* エラーモーダル */
.error-modal-container {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.5);
    display: none;
    align-items: center;
    justify-content: center;
    z-index: 10001;
    opacity: 0;
    transition: opacity 0.3s ease;
}

.error-modal-container.error-modal-show {
    opacity: 1;
}

.error-modal {
    background: white;
    border-radius: 12px;
    padding: 0;
    max-width: 500px;
    width: 90%;
    max-height: 80vh;
    overflow: hidden;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.2);
    transform: scale(0.9);
    transition: transform 0.3s ease;
}

.error-modal-container.error-modal-show .error-modal {
    transform: scale(1);
}

.error-modal-content {
    padding: 24px;
}

.error-modal-title {
    margin: 0 0 16px 0;
    font-size: 20px;
    color: #d32f2f;
    display: flex;
    align-items: center;
    gap: 8px;
}

.error-modal-message {
    font-size: 16px;
    line-height: 1.6;
    color: var(--text-primary);
    margin-bottom: 20px;
}

.error-modal-details {
    margin-top: 16px;
    padding: 12px;
    background: #f5f5f5;
    border-radius: 4px;
    font-size: 12px;
}

.error-modal-details summary {
    cursor: pointer;
    font-weight: 500;
    margin-bottom: 8px;
}

.error-modal-details pre {
    margin: 0;
    overflow-x: auto;
    white-space: pre-wrap;
    word-break: break-all;
}

.error-modal-buttons {
    display: flex;
    gap: 12px;
    justify-content: flex-end;
}

.error-modal-button {
    padding: 10px 20px;
    border: none;
    border-radius: 6px;
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
}

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

.error-modal-retry:hover {
    background: var(--primary-dark);
}

.error-modal-close {
    background: #e0e0e0;
    color: #333;
}

.error-modal-close:hover {
    background: #d0d0d0;
}

/* インラインエラー表示 */
.inline-error {
    color: #d32f2f;
    font-size: 12px;
    margin-top: 4px;
    animation: shake 0.3s ease;
}

@keyframes shake {
    0%, 100% { transform: translateX(0); }
    25% { transform: translateX(-5px); }
    75% { transform: translateX(5px); }
}

.error {
    border-color: #d32f2f !important;
    background-color: #ffebee !important;
}

/* モバイル向けエラー表示調整 */
@media (max-width: 600px) {
    .error-toast-container {
        top: 10px;
        right: 10px;
        left: 10px;
    }
    
    .error-toast {
        min-width: auto;
        width: 100%;
    }
    
    .error-modal {
        width: 95%;
        margin: 10px;
    }
}