/* CSS cho frontend Kanji Learning - Version 3.0.0 with Complete Lesson System */

* {
    box-sizing: border-box;
}

:root {
    /* Primary Colors */
    --primary: #667eea;
    --primary-hover: #5a67d8;
    --success: #059669;
    --error: #dc2626;
    --warning: #d97706;
    --info: #3b82f6;
    
    /* Teal Colors for Arrows */
    --teal-light: #14b8a6;
    --teal-medium: #0d9488;
    --teal-dark: #0f766e;
    --teal-darker: #134e4a;
    
    /* Extended Colors */
    --purple: #7c3aed;
    --brown: #92400e;
    --teal: #0891b2;
    --blue-dark: #1e40af;
    --blue-darker: #1e3a8a;
    
    /* Ruby Text Colors */
    --ruby-main: #00695c;
    --ruby-rt: #e67e22;
    
    /* Lesson Colors */
    --lesson-bg: #f0f9ff;
    --lesson-border: #0ea5e9;
    --lesson-text: #0c4a6e;
    --lesson-active: #0891b2;
    --lesson-complete: #10b981;
    
    /* Text Colors */
    --text-primary: #1f2937;
    --text-secondary: #4b5563;
    --text-muted: #9ca3af;
    
    /* Background Colors */
    --bg-white: #ffffff;
    --bg-light: #f3f4f6;
    --bg-red: #fee2e2;
    --bg-green: #dcfce7;
    --bg-yellow: #fef3c7;
    --bg-orange: #fff7ed;
    --bg-purple: rgba(124, 58, 237, 0.05);
    
    /* Border Colors */
    --border-default: #9ca3af;
    --border-light: #e5e7eb;
    
    /* JLPT Colors */
    --jlpt-n5: #dc2626;
    --jlpt-n4: #059669;
    --jlpt-n3: #1e40af;
    --jlpt-n2: #d97706;
    --jlpt-n1: #5b21b6;
    
    /* Shadows */
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.05);
    --shadow-md: 0 4px 8px rgba(0,0,0,0.1);
    --shadow-lg: 0 10px 30px rgba(0,0,0,0.15);
    --shadow-xl: 0 10px 40px rgba(0,0,0,0.2);
    
    /* Layout */
    --container-max: 1200px;
    --min-content-height: 500px;
    
    /* Animation */
    --transition: all 0.3s ease;
    
    /* Spacing */
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-xl: 16px;
    --radius-full: 25px;
}

/* ===== BASE STYLES ===== */
.kanji-learning-wrapper {
    width: 100%;
    background: var(--bg-white);
}

.kanji-learning-container {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 20px;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    -webkit-font-smoothing: antialiased;
    color: var(--text-primary);
    background: var(--bg-white);
    position: relative;
}

/* ===== HEADER ===== */
.kanji-header {
    text-align: center;
    padding: 30px 20px;
    background: var(--bg-white);
    border: 2px solid var(--blue-dark);
    border-radius: var(--radius-lg);
    margin-bottom: 30px;
    position: relative;
}

.kanji-header h2 {
    margin: 0;
    font-size: 32px;
    font-weight: 700;
    color: var(--blue-dark);
}

.kanji-header p {
    margin: 12px 0 0;
    color: var(--text-secondary);
    font-size: 16px;
}

#sound-toggle {
    position: absolute;
    top: 20px;
    right: 20px;
    background: transparent;
    border: 2px solid var(--blue-dark);
    border-radius: 20px;
    padding: 5px 15px;
    cursor: pointer;
    color: var(--blue-dark);
    font-size: 14px;
    transition: var(--transition);
}

#sound-toggle:hover {
    background: var(--blue-dark);
    color: white;
}

/* JLPT Selector */
.jlpt-selector {
    display: flex;
    gap: 10px;
    justify-content: center;
    margin-top: 20px;
    flex-wrap: wrap;
}

.jlpt-btn {
    padding: 8px 16px;
    background: var(--bg-white);
    border: 2px solid var(--blue-dark);
    border-radius: var(--radius-full);
    cursor: pointer;
    transition: var(--transition);
    font-weight: 600;
    color: var(--text-secondary);
    position: relative;
}

.jlpt-btn[data-level="N5"] { color: var(--jlpt-n5); border-color: var(--jlpt-n5); }
.jlpt-btn[data-level="N4"] { color: var(--jlpt-n4); border-color: var(--jlpt-n4); }
.jlpt-btn[data-level="N3"] { color: var(--jlpt-n3); border-color: var(--jlpt-n3); }
.jlpt-btn[data-level="N2"] { color: var(--jlpt-n2); border-color: var(--jlpt-n2); }
.jlpt-btn[data-level="N1"] { color: var(--jlpt-n1); border-color: var(--jlpt-n1); }

.jlpt-btn .count {
    display: inline-block;
    background: #fffbeb;
    padding: 2px 6px;
    border-radius: 10px;
    font-size: 12px;
    margin-left: 5px;
}

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

.jlpt-btn.active {
    background: var(--bg-green);
    border-color: var(--success);
    color: var(--success);
}

/* ===== LESSON SELECTOR ===== */
.lesson-selector {
    display: flex;
    gap: 8px;
    justify-content: center;
    margin: 20px 0 0;
    flex-wrap: wrap;
    padding: 15px;
    background: var(--lesson-bg);
    border-radius: var(--radius-lg);
    border: 2px solid var(--lesson-border);
    align-items: center;
}

.lesson-selector > span {
    font-weight: 600;
    color: var(--lesson-text);
    margin-right: 10px;
    font-size: 15px;
}

.lesson-btn {
    padding: 7px 14px;
    background: var(--bg-white);
    border: 2px solid var(--border-light);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: var(--transition);
    font-size: 13px;
    font-weight: 500;
    color: var(--teal-dark);
    position: relative;
}

.lesson-btn:hover {
    background: rgba(8, 145, 178, 0.1); /* Xanh teal nhạt */
    border-color: var(--lesson-active);
    color: var(--lesson-active);
    transform: translateY(-1px);
    box-shadow: var(--shadow-sm);
}

.lesson-btn.active {
    background: var(--lesson-active);
    border-color: var(--lesson-active);
    color: white;
    box-shadow: var(--shadow-md);
}

.lesson-btn.completed {
    background: var(--lesson-complete);
    border-color: var(--lesson-complete);
    color: white;
}

.lesson-btn.completed::after {
    content: '✓';
    position: absolute;
    top: -5px;
    right: -5px;
    width: 18px;
    height: 18px;
    background: var(--success);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 10px;
    font-weight: bold;
}

.lesson-range {
    font-size: 11px;
    opacity: 0.8;
    margin-left: 4px;
}

/* Current Lesson Info */
.current-lesson-info {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 10px 15px;
    background: var(--lesson-bg);
    border-radius: var(--radius-md);
    margin-bottom: 15px;
    border: 1px solid var(--lesson-border);
}

.lesson-badge {
    font-weight: 600;
    color: var(--lesson-text);
}

.btn-clear-lesson {
    background: transparent;
    border: 1px solid var(--lesson-border);
    padding: 4px 10px;
    border-radius: var(--radius-sm);
    cursor: pointer;
    color: var(--lesson-text);
    font-size: 13px;
    transition: var(--transition);
}

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

/* Kanji Card Lesson Badge */
.kanji-lesson-badge {
    position: absolute;
    bottom: 5px;
    right: 5px;
    padding: 2px 6px;
    background: var(--lesson-bg);
    color: var(--lesson-text);
    border-radius: var(--radius-sm);
    font-size: 10px;
    font-weight: 600;
    border: 1px solid var(--lesson-border);
    opacity: 0.7;
    transition: opacity 0.2s;
}

.kanji-card:hover .kanji-lesson-badge {
    opacity: 1;
}

/* Flashcard Lesson Info */
.flashcard-lesson-info {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 10px 15px;
    background: linear-gradient(135deg, var(--lesson-bg) 0%, rgba(14, 165, 233, 0.05) 100%);
    border-radius: var(--radius-md);
    margin-bottom: 15px;
    border: 1px solid var(--lesson-border);
}

.current-lesson-display {
    font-weight: 600;
    color: var(--lesson-text);
    font-size: 15px;
}

.lesson-quick-nav {
    display: flex;
    gap: 8px;
}

.lesson-quick-nav button {
    width: 32px;
    height: 32px;
    border-radius: var(--radius-sm);
    border: 1px solid var(--lesson-border);
    background: var(--bg-white);
    color: var(--lesson-text);
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 16px;
}

.lesson-quick-nav button:hover {
    background: var(--lesson-active);
    color: white;
    border-color: var(--lesson-active);
}

.lesson-quick-nav button:disabled {
    opacity: 0.3;
    cursor: not-allowed;
}

/* Practice Lesson Selector */
.practice-lesson-selector {
    margin-bottom: 20px;
    padding: 15px;
    background: var(--bg-light);
    border-radius: var(--radius-md);
    border: 2px solid var(--blue-dark);
}

.practice-lesson-selector label {
    display: flex;
    align-items: center;
    gap: 10px;
    font-weight: 600;
    color: var(--text-primary);
}

.practice-lesson-selector select {
    padding: 8px 15px;
    border: 2px solid var(--lesson-border);
    border-radius: var(--radius-sm);
    background: var(--bg-white);
    font-size: 14px;
    cursor: pointer;
}

/* Lesson Progress Grid */
.lesson-progress-tracking {
    margin-top: 30px;
    padding: 20px;
    background: var(--bg-light);
    border-radius: var(--radius-lg);
}

.lesson-progress-tracking h4 {
    color: var(--lesson-text);
    margin-bottom: 20px;
    font-size: 18px;
}

.lesson-progress-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
    gap: 15px;
}

.lesson-progress-item {
    background: var(--bg-white);
    border: 2px solid var(--border-light);
    border-radius: var(--radius-md);
    padding: 12px;
    transition: var(--transition);
    cursor: pointer;
}

.lesson-progress-item:hover {
    border-color: var(--lesson-border);
    box-shadow: var(--shadow-sm);
}

.lesson-progress-item.completed {
    border-color: var(--lesson-complete);
    background: linear-gradient(135deg, var(--bg-white) 0%, rgba(16, 185, 129, 0.05) 100%);
}

.lesson-progress-item .lesson-header {
    display: flex;
    justify-content: space-between;
    margin-bottom: 8px;
    font-size: 13px;
    font-weight: 600;
}

.lesson-status {
    color: var(--text-muted);
    font-size: 11px;
}

.lesson-status.in-progress {
    color: var(--warning);
}

.lesson-status.completed {
    color: var(--lesson-complete);
}

.lesson-progress-bar {
    height: 6px;
    background: var(--border-light);
    border-radius: 3px;
    overflow: hidden;
    margin-bottom: 8px;
}

.lesson-progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--lesson-active), var(--lesson-complete));
    transition: width 0.5s ease;
}

.lesson-stats {
    font-size: 11px;
    color: var(--text-secondary);
    text-align: center;
}

/* Complete Lesson Button */
#btn-complete-lesson {
    background: var(--lesson-complete);
    border-color: var(--lesson-complete);
    color: white;
}

#btn-complete-lesson:hover {
    background: var(--success);
    border-color: var(--success);
}

/* ===== LESSON MENU MODAL ===== */
.lesson-menu-modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(4px);
    -webkit-backdrop-filter: blur(4px);
    z-index: 10000;
    display: none;
    align-items: center;
    justify-content: center;
    opacity: 0;
    transition: opacity 0.3s ease;
}

.lesson-menu-modal.show {
    display: flex;
    opacity: 1;
}

.lesson-menu-content {
    background: var(--bg-white);
    border-radius: var(--radius-xl);
    padding: 30px;
    max-width: 600px;
    width: 90%;
    max-height: 80vh;
    overflow-y: auto;
    box-shadow: var(--shadow-xl);
    transform: translateY(20px);
    opacity: 0;
    animation: slideUpModal 0.3s ease forwards;
}

.lesson-menu-modal.show .lesson-menu-content {
    animation-delay: 0.1s;
}

.lesson-menu-content h3 {
    margin: 0 0 20px;
    color: var(--blue-dark);
    text-align: center;
    font-size: 22px;
    font-weight: 700;
}

.lesson-menu-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(120px, 1fr));
    gap: 12px;
    margin-bottom: 20px;
}

.lesson-menu-item {
    padding: 15px 10px;
    border: 2px solid var(--border-light);
    border-radius: var(--radius-md);
    background: var(--bg-white);
    cursor: pointer;
    transition: var(--transition);
    text-align: center;
    position: relative;
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.lesson-menu-item:hover {
    border-color: var(--lesson-border);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
    background: var(--lesson-bg);
}

.lesson-menu-item.active {
    background: var(--lesson-active);
    border-color: var(--lesson-active);
    color: white;
}

.lesson-menu-item.active:hover {
    background: var(--teal-dark);
    border-color: var(--teal-dark);
}

.lesson-menu-item.complete {
    background: var(--lesson-complete);
    border-color: var(--lesson-complete);
    color: white;
}

.lesson-menu-item.complete:hover {
    background: var(--success);
    border-color: var(--success);
}

.lesson-menu-item span {
    display: block;
}

.lesson-menu-item span:first-child {
    font-weight: 600;
    font-size: 14px;
}

.lesson-progress-text {
    font-size: 11px;
    opacity: 0.8;
}

.complete-icon {
    position: absolute;
    top: 5px;
    right: 5px;
    font-size: 12px;
    background: white;
    color: var(--lesson-complete);
    width: 18px;
    height: 18px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: bold;
    box-shadow: var(--shadow-sm);
}

.close-menu {
    display: block;
    margin: 0 auto;
    padding: 10px 30px;
    background: var(--text-secondary);
    color: white;
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    font-size: 14px;
    font-weight: 600;
    transition: var(--transition);
}

.close-menu:hover {
    background: var(--text-primary);
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

/* Modal Animations */
@keyframes fadeInModal {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

@keyframes slideUpModal {
    from {
        transform: translateY(20px);
        opacity: 0;
    }
    to {
        transform: translateY(0);
        opacity: 1;
    }
}

/* Scrollbar for modal */
.lesson-menu-content::-webkit-scrollbar {
    width: 8px;
}

.lesson-menu-content::-webkit-scrollbar-track {
    background: var(--bg-light);
    border-radius: 4px;
}

.lesson-menu-content::-webkit-scrollbar-thumb {
    background: var(--border-default);
    border-radius: 4px;
}

.lesson-menu-content::-webkit-scrollbar-thumb:hover {
    background: var(--text-secondary);
}

/* ===== TABS ===== */
.kanji-tabs {
    display: flex;
    justify-content: center;
    gap: 8px;
    margin-bottom: 30px;
    background: var(--bg-white);
    padding: 8px;
    border-radius: var(--radius-md);
    border: 2px solid var(--blue-dark);
}

.kanji-tab {
    padding: 12px 24px;
    background: transparent;
    border: 2px solid transparent;
    border-radius: 6px;
    cursor: pointer;
    font-size: 15px;
    font-weight: 600;
    color: var(--teal-dark);
    transition: var(--transition);
}

.kanji-tab:hover {
    border-color: var(--teal);
    color: var(--teal);
}

.kanji-tab.active {
    border-color: var(--purple);
    color: var(--purple);
    background: var(--bg-purple);
}

/* ===== TAB CONTENT ===== */
.kanji-tab-content {
    background: var(--bg-white);
    padding: 30px;
    border-radius: var(--radius-lg);
    border: 2px solid var(--blue-dark);
    min-height: var(--min-content-height);
    display: flex;
    flex-direction: column;
}

/* ===== LIST CONTROLS ===== */
.kanji-list-controls {
    display: flex;
    gap: 20px;
    margin-bottom: 20px;
    flex-wrap: wrap;
    align-items: center;
}

.kanji-search-box {
    flex: 1;
    min-width: 250px;
}

#kanji-search {
    width: 100%;
    padding: 12px 16px;
    font-size: 15px;
    border: 2px solid #9ca3af;
    border-radius: var(--radius-md);
    outline: none;
    transition: var(--transition);
}

#kanji-search:focus {
    border-color: var(--blue-dark);
    box-shadow: 0 0 0 3px rgba(30, 64, 175, 0.1);
}

.kanji-sort-options select {
    padding: 10px 12px;
    border: 2px solid #9ca3af;
    border-radius: var(--radius-md);
    font-size: 14px;
    background: var(--bg-white);
    cursor: pointer;
    transition: var(--transition);
}

.kanji-sort-options select:focus {
    border-color: var(--blue-dark);
    outline: none;
}

/* ===== KANJI GRID ===== */
.kanji-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
    gap: 16px;
    flex: 1;
}

.kanji-card {
    background: var(--bg-white);
    border: 2px solid #d78919;
    border-radius: 10px;
    padding: 15px 12px;
    text-align: center;
    transition: var(--transition);
    cursor: pointer;
    position: relative;
    overflow: visible;
}

.kanji-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: #059669;
}

.kanji-card.lesson-hidden {
    display: none !important;
}

.kanji-number {
    position: absolute;
    top: 5px;
    left: 5px;
    padding: 3px 8px;
    background: #fff4f4;
    color: #92400e;
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 11px;
    font-weight: bold;
    z-index: 2;
    backdrop-filter: blur(2px);
    border: 1px solid rgba(220, 38, 38, 0.2);
}

.kanji-jlpt-badge {
    position: absolute;
    top: 5px;
    right: 5px;
    padding: 3px 8px;
    border-radius: var(--radius-sm);
    font-size: 11px;
    font-weight: bold;
    background: var(--bg-green);
    color: var(--success);
    z-index: 2;
}

.kanji-svg {
    width: 90px;
    height: 90px;
    margin: 10px auto 12px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.kanji-svg img {
    width: 100%;
    height: 100%;
    object-fit: contain;
}

.kanji-main {
    font-size: 52px;
    font-weight: 900;
    color: var(--blue-dark);
    margin: 10px 0 12px;
    line-height: 1;
    height: 90px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.kanji-info {
    font-size: 14px;
}

.kanji-meaning {
    color: #dc2626;
    font-weight: 600;
    margin-bottom: 6px;
    font-size: 14px;
}

.kanji-hanviet {
    color: var(--purple);
    font-size: 13px;
    font-weight: 500;
    margin: 3px 0;
}

.kanji-on, .kanji-kun {
    font-size: 11px;
    color: var(--text-secondary);
    margin: 2px 0;
    display: inline-block;
}

.kanji-on::after {
    content: " | ";
    margin: 0 4px;
    color: var(--border-default);
}

.kanji-kun::before {
    content: "";
}

.kanji-tooltip {
    display: none;
    position: absolute;
    bottom: calc(100% + 12px);
    left: 50%;
    transform: translateX(-50%);
    background: var(--bg-yellow);
    color: black;
    padding: 10px 14px;
    border-radius: 6px;
    font-size: 12px;
    width: 220px;
    z-index: 100;
    box-shadow: var(--shadow-lg);
    white-space: normal;
    border: 1px solid var(--warning);
}

.kanji-card:hover .kanji-tooltip {
    display: block;
}

.kanji-tooltip::after {
    content: '';
    position: absolute;
    top: 100%;
    left: 50%;
    transform: translateX(-50%);
    border: 6px solid transparent;
    border-top-color: var(--bg-yellow);
}

/* ===== RUBY TEXT SUPPORT ===== */
ruby {
    display: inline-ruby;
    ruby-position: over !important;
    -webkit-ruby-position: before !important;
    position: relative;
    color: var(--ruby-main);
}

rt {
    font-size: 0.5em;
    color: var(--ruby-rt);
    line-height: 1.2;
    text-align: center;
    font-weight: normal;
    ruby-align: center;
    display: ruby-text;
}

/* Fallback for older browsers */
@supports not (display: ruby) {
    ruby {
        display: inline-block;
        position: relative;
        text-align: center;
        color: var(--ruby-main);
    }
    
    ruby rt {
        display: block;
        font-size: 0.5em;
        line-height: 1.2;
        position: absolute;
        top: -1em;
        left: 0;
        right: 0;
        text-align: center;
        color: var(--ruby-rt);
    }
}

/* ===== FLASHCARD STYLES ===== */
.flashcard-container,
.practice-container,
.quiz-container,
.progress-container {
    max-width: 700px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    justify-content: center;
    min-height: calc(var(--min-content-height) - 60px);
}

.flashcard-container {
    max-width: 900px;
}

.progress-container {
    max-width: 800px;
}

.flashcard-container h3,
.practice-container h3,
.quiz-container h3,
.progress-container h3 {
    text-align: center;
    margin-bottom: 10px;
    font-size: 24px;
    font-weight: 700;
}

.flashcard-container h3 { color: var(--purple); }
.practice-container h3 { color: var(--success); }
.quiz-container h3 { color: var(--error); }
.progress-container h3 { color: var(--brown); margin-bottom: 30px; }

.flashcard-desc {
    text-align: center;
    color: var(--text-secondary);
    margin-bottom: 30px;
    font-size: 15px;
}

/* Settings Box */
.flashcard-settings,
.practice-settings,
.quiz-mode-selector {
    background: #fef3c7;
    padding: 15px;
    border-radius: var(--radius-md);
    margin-bottom: 20px;
    display: flex;
    justify-content: center;
    gap: 20px;
    flex-wrap: wrap;
    border: 2px solid var(--blue-dark);
}

.flashcard-settings label,
.practice-settings label,
.quiz-mode-selector label {
    display: flex;
    align-items: center;
    gap: 8px;
    cursor: pointer;
    font-size: 14px;
    color: var(--text-primary);
}

.practice-settings label {
    font-weight: 600;
    margin-right: 10px;
}

input[type="checkbox"],
input[type="radio"] {
    cursor: pointer;
    accent-color: var(--warning);
}

.practice-settings select {
    padding: 8px 15px;
    border: 2px solid var(--warning);
    border-radius: 6px;
    font-size: 14px;
    background: var(--bg-white);
    cursor: pointer;
}

/* Flashcard Display */
.vocab-container {
    perspective: 1500px;
    margin-bottom: 25px;
    position: relative;
    padding: 0;
}

.vocab-container .flashcard {
    position: relative;
    width: 100%;
    height: 420px;
}

.card-index {
    position: absolute;
    top: 15px;
    left: 15px;
    font-size: 14px;
    color: var(--blue-darker);
    font-weight: 600;
    background: rgba(167, 243, 208, 0.6);
    padding: 8px 16px;
    z-index: 15;
    border: none;
    clip-path: polygon(50% 0%, 100% 25%, 100% 75%, 50% 100%, 0% 75%, 0% 25%);
    backdrop-filter: blur(3px);
    -webkit-backdrop-filter: blur(3px);
}

/* ===== FLASHCARD ARROW BUTTONS ===== */
.flashcard-arrow {
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    width: 44px;
    height: 44px;
    background: rgba(20, 184, 166, 0.12);
    border: 2px solid rgba(20, 184, 166, 0.25);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    z-index: 20;
    opacity: 0.6;
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
}

.flashcard-arrow:hover:not(:disabled) {
    opacity: 1;
    background: rgba(20, 184, 166, 0.2);
    border-color: var(--teal-light);
    transform: translateY(-50%) scale(1.1);
    box-shadow: 0 8px 25px rgba(20, 184, 166, 0.35);
}

.flashcard-arrow:active:not(:disabled) {
    transform: translateY(-50%) scale(0.95);
    background: rgba(20, 184, 166, 0.3);
}

.flashcard-arrow:disabled {
    opacity: 0.15;
    cursor: not-allowed;
    background: rgba(156, 163, 175, 0.08);
    border-color: rgba(156, 163, 175, 0.15);
}

.flashcard-arrow-left {
    left: 0px;
}

.flashcard-arrow-right {
    right: 0px;
}

.flashcard-arrow svg {
    width: 24px;
    height: 24px;
    stroke: var(--teal-dark);
    stroke-width: 2.5;
    fill: none;
    filter: drop-shadow(0 2px 4px rgba(15, 118, 110, 0.25));
}

.flashcard-arrow:hover:not(:disabled) svg {
    stroke: var(--teal-darker);
    stroke-width: 3;
    filter: drop-shadow(0 2px 4px rgba(15, 118, 110, 0.4));
}

.flashcard-arrow:disabled svg {
    stroke: var(--text-muted);
    stroke-width: 2;
    filter: none;
}

.flashcard-arrow:focus {
    outline: 3px solid rgba(20, 184, 166, 0.5);
    outline-offset: 2px;
}

.card-inner {
    position: relative;
    width: 100%;
    height: 100%;
    transition: transform 0.6s cubic-bezier(0.4, 0, 0.2, 1);
    transform-style: preserve-3d;
    cursor: pointer;
}

.card-inner.flipped {
    transform: rotateY(180deg);
}

.card-front,
.card-back {
    position: absolute;
    width: 100%;
    height: 100%;
    -webkit-backface-visibility: hidden;
    backface-visibility: hidden;
    border-radius: var(--radius-xl);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    background: var(--bg-white);
    border: 3px solid var(--blue-dark);
    box-shadow: var(--shadow-lg);
    padding: 30px 70px;
}

.card-front {
    transform: rotateY(0deg);
}

.card-back {
    transform: rotateY(180deg);
}

.flip-hint {
    position: absolute;
    bottom: 20px;
    font-size: 13px;
    opacity: 0.6;
    font-weight: 500;
    color: var(--text-secondary);
}

.flashcard-kanji-display {
    text-align: center;
}

.flashcard-kanji-display .kanji-text {
    font-size: 140px;
    color: var(--blue-dark);
    font-weight: 900;
    line-height: 1;
}

.flashcard-kanji-display .kanji-svg-large {
    width: 260px;
    height: 260px;
    background: var(--bg-light);
    border-radius: var(--radius-lg);
    padding: 20px;
    border: 2px solid var(--blue-dark);
}

.flashcard-kanji-display .kanji-svg-large img {
    width: 100%;
    height: 100%;
    object-fit: contain;
}

.flashcard-info {
    text-align: center;
    width: 100%;
    display: flex;
    flex-direction: column;
    gap: 15px;
    max-width: 100%;
}

.flashcard-hanviet {
    font-size: 36px;
    color: var(--purple);
    font-weight: 700;
    margin: 0;
    text-transform: uppercase;
    letter-spacing: 2px;
}

.flashcard-meaning {
    font-size: 26px;
    color: var(--brown);
    margin: 0;
    font-weight: 600;
    padding: 12px 25px;
    background: #fffbeb;
    border-radius: var(--radius-md);
    display: inline-block;
}

.flashcard-on-kun {
    margin: 0;
    padding: 10px 20px;
    background: var(--bg-white);
    border: 2px solid var(--teal);
    border-radius: var(--radius-md);
    color: var(--teal);
    font-weight: 500;
    font-size: 16px;
    display: none;
}

.flashcard-on-kun:not(:empty) {
    display: flex;
    justify-content: center;
    gap: 30px;
}

.flashcard-on-kun div {
    display: inline-block;
}

.flashcard-on-kun div:first-child::after {
    content: " | ";
    margin: 0 15px;
    color: var(--border-default);
}

.flashcard-explain {
    font-size: 16px;
    color: var(--ruby-main);
    line-height: 1.6;
    margin: 0;
    font-style: italic;
    padding: 0 30px;
    max-width: 100%;
}

.flashcard-examples {
    margin-top: 15px;
    padding: 15px;
    background: var(--bg-light);
    border-radius: var(--radius-md);
    font-size: 14px;
    line-height: 1.6;
    position: relative;
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    max-width: 100%;
    width: 100%;
}

.flashcard-examples::before {
    content: 'Ví dụ';
    position: absolute;
    top: -8px;
    left: 15px;
    background: var(--bg-white);
    padding: 0 10px;
    font-size: 12px;
    font-weight: 600;
    color: var(--brown);
    border-radius: var(--radius-sm);
    border: 1px solid var(--border-light);
}

.flashcard-examples .example-item {
    display: inline-flex;
    align-items: baseline;
    gap: 12px;
    padding: 6px 12px;
    background: var(--bg-white);
    border-radius: var(--radius-sm);
    border: 1px solid var(--border-light);
    white-space: nowrap;
}

.flashcard-examples .example-jp {
    color: var(--ruby-main);
    font-weight: 500;
    font-size: 14px;
}

.flashcard-examples .example-vn {
    color: var(--text-secondary);
    font-size: 13px;
}

/* Progress Bar */
.progress-bar {
    width: 100%;
    height: 8px;
    background: var(--border-light);
    border-radius: var(--radius-sm);
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--blue-dark), var(--purple));
    transition: width 0.5s ease;
}

.flashcard-progress {
    margin-bottom: 25px;
}

.flashcard-progress .progress-bar {
    height: 6px;
}

/* Button icons */
#btn-shuffle-cards::before {
    content: '🔀 ';
    margin-right: 4px;
}

#btn-auto-play::before {
    content: '▶ ';
    margin-right: 4px;
}

#btn-auto-play.active::before {
    content: '⏸ ';
}

#btn-reset-cards::before {
    content: '↻ ';
    margin-right: 4px;
}

#btn-complete-lesson::before {
    content: '✓ ';
    margin-right: 4px;
}

.flashcard-controls {
    display: flex;
    justify-content: center;
    gap: 15px;
}

.btn-control {
    padding: 10px 20px;
    background: transparent;
    border: 2px solid var(--blue-dark);
    border-radius: 10px;
    color: var(--blue-dark);
    font-weight: 600;
    font-size: 14px;
    cursor: pointer;
    transition: var(--transition);
}

.btn-control:hover {
    border-color: var(--purple);
    color: var(--purple);
    transform: translateY(-2px);
}

.btn-control.active {
    border-color: var(--success);
    color: var(--success);
}

/* ===== PRACTICE & QUIZ STYLES ===== */
.practice-question,
.quiz-question {
    background: var(--bg-white);
    color: var(--text-primary);
    padding: 35px 25px;
    border-radius: var(--radius-lg);
    text-align: center;
    margin-bottom: 30px;
    min-height: 120px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 20px;
    font-weight: 600;
}

.practice-question { border: 3px solid var(--success); }
.quiz-question { border: 3px solid var(--error); }

.practice-options,
.quiz-options {
    display: flex !important;
    flex-wrap: wrap;
    gap: 12px;
    justify-content: center;
    margin-bottom: 30px;
}

.option-button {
    padding: 20px;
    background: var(--bg-white);
    border: 2px solid var(--blue-dark);
    border-radius: 10px;
    font-size: 24px;
    font-weight: 700;
    cursor: pointer;
    transition: var(--transition);
    color: var(--text-primary);
    position: relative;
    flex: 0 1 auto;
}

.option-button.short-content {
    min-width: 80px;
    max-width: 120px;
    flex: 0 1 calc(25% - 12px);
}

.option-button.medium-content {
    min-width: 120px;
    flex: 0 1 calc(33.333% - 12px);
}

.option-button.long-content {
    min-width: 180px;
    flex: 0 1 calc(50% - 12px);
}

.option-button:hover:not(:disabled) {
    background: var(--bg-light);
    border-color: var(--warning);
    transform: translateY(-2px);
    color: var(--warning);
}

.option-button.selected {
    background: var(--bg-orange);
    border-color: var(--warning);
}

.option-button.correct {
    background: #f0fdf4;
    color: var(--success);
    border-color: var(--success);
    animation: correctPulse 0.5s ease;
}

.option-button.wrong {
    background: #fef2f2;
    color: var(--error);
    border-color: var(--error);
    animation: wrongShake 0.5s ease;
}

@keyframes correctPulse {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.05); }
}

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

.icon-result {
    position: absolute;
    top: 5px;
    right: 10px;
    font-size: 24px;
    font-weight: bold;
}

.practice-progress {
    margin-bottom: 20px;
    text-align: center;
}

.practice-progress span {
    display: block;
    margin-bottom: 8px;
    color: var(--text-secondary);
    font-size: 14px;
    font-weight: 600;
}

.practice-progress .progress-fill {
    background: var(--warning);
}

.practice-controls,
.quiz-controls {
    text-align: center;
    margin-bottom: 30px;
}

.btn-primary,
.btn-secondary {
    padding: 12px 28px;
    font-size: 15px;
    border: 2px solid var(--blue-dark);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: var(--transition);
    font-weight: 600;
    background: transparent;
    color: var(--blue-dark);
}

.btn-primary:hover {
    border-color: var(--purple);
    color: var(--purple);
    transform: translateY(-2px);
}

.practice-stats {
    display: flex;
    justify-content: center;
    gap: 35px;
    padding: 20px;
    background: var(--bg-light);
    border-radius: 10px;
    border: 2px solid var(--blue-dark);
}

.practice-stats span {
    color: var(--text-secondary);
    font-size: 14px;
}

.practice-stats strong {
    color: var(--text-primary);
    font-size: 22px;
    font-weight: 700;
    margin-left: 6px;
}

.quiz-score {
    text-align: center;
    padding: 20px;
    background: #fff7ed;
    border-radius: 10px;
    border: 2px solid var(--blue-dark);
}

.score-bar {
    width: 100%;
    height: 24px;
    background: #dcfce7;
    border-radius: 12px;
    overflow: hidden;
    margin-bottom: 15px;
}

.score-fill {
    height: 100%;
    background: var(--success);
    transition: width 0.5s ease;
}

/* Final Results */
.practice-final-result {
    text-align: center;
    padding: 30px;
    background: var(--bg-white);
    border-radius: var(--radius-lg);
    border: 2px solid var(--blue-dark);
}

.practice-final-result h3 {
    color: var(--purple);
    font-size: 28px;
    margin-bottom: 25px;
}

.result-stats {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 20px;
    margin: 30px 0;
    padding: 25px;
    background: var(--bg-light);
    border-radius: 10px;
}

.stat-item {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.stat-label {
    color: var(--text-secondary);
    font-size: 14px;
    margin-bottom: 5px;
}

.stat-value {
    color: var(--warning);
    font-size: 24px;
    font-weight: 700;
}

.evaluation {
    padding: 15px;
    border-radius: var(--radius-md);
    margin: 20px 0;
    font-size: 16px;
    font-weight: 500;
}

.evaluation.excellent {
    background: #f0fdf4;
    color: var(--success);
    border: 2px solid var(--success);
}

.evaluation.good {
    background: #eff6ff;
    color: var(--blue-dark);
    border: 2px solid var(--blue-dark);
}

.evaluation.medium {
    background: #fffbeb;
    color: var(--brown);
    border: 2px solid #fbbf24;
}

.evaluation.need-improve {
    background: var(--bg-orange);
    color: var(--warning);
    border: 2px solid var(--warning);
}

#btn-restart-practice {
    margin-top: 20px;
}

/* ===== PROGRESS TAB ===== */
.progress-overview {
    margin-bottom: 30px;
}

.level-progress {
    margin-bottom: 20px;
}

.level-header {
    display: flex;
    justify-content: space-between;
    margin-bottom: 8px;
    font-weight: 600;
    color: var(--text-primary);
}

.level-bar {
    height: 20px;
    background: var(--bg-light);
    border-radius: 10px;
    overflow: hidden;
    border: 2px solid var(--blue-dark);
}

.level-fill {
    height: 100%;
    transition: width 0.5s ease;
}

.level-fill.level-n5 { background: var(--jlpt-n5); }
.level-fill.level-n4 { background: var(--jlpt-n4); }
.level-fill.level-n3 { background: var(--jlpt-n3); }
.level-fill.level-n2 { background: var(--jlpt-n2); }
.level-fill.level-n1 { background: var(--jlpt-n1); }

.user-stats {
    margin-top: 30px;
}

.user-stats h4 {
    color: var(--teal);
    font-size: 20px;
    margin-bottom: 20px;
    text-align: center;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 20px;
    margin-top: 20px;
}

.login-prompt {
    text-align: center;
    padding: 40px;
    background: var(--bg-light);
    border-radius: 10px;
    border: 2px solid var(--blue-dark);
}

.login-prompt .btn-primary {
    margin-top: 20px;
}

/* ===== TOAST NOTIFICATIONS ===== */
.kanji-toast-container {
    position: fixed;
    bottom: 20px;
    right: 20px;
    z-index: 10000;
    pointer-events: none;
}

.kanji-toast-notification {
    background: var(--bg-white);
    border-radius: var(--radius-lg);
    margin-top: 10px;
    min-width: 300px;
    max-width: 400px;
    box-shadow: var(--shadow-xl);
    overflow: hidden;
    pointer-events: all;
    transform: translateX(400px);
    transition: transform 0.3s cubic-bezier(0.68, -0.55, 0.265, 1.55);
}

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

.toast-content {
    padding: 16px 20px;
    display: flex;
    align-items: center;
    gap: 12px;
}

.toast-icon {
    font-size: 24px;
    font-weight: bold;
}

.kanji-toast-notification.success { border-left: 4px solid var(--success); }
.kanji-toast-notification.success .toast-icon { color: var(--success); }
.kanji-toast-notification.error { border-left: 4px solid var(--error); }
.kanji-toast-notification.error .toast-icon { color: var(--error); }
.kanji-toast-notification.info { border-left: 4px solid var(--info); }
.kanji-toast-notification.info .toast-icon { color: var(--info); }

.toast-message {
    flex: 1;
    color: var(--text-primary);
    font-size: 15px;
    font-weight: 500;
}

.toast-progress {
    height: 3px;
    background: var(--border-light);
}

.toast-progress-bar {
    height: 100%;
    width: 100%;
    background: linear-gradient(90deg, var(--info), var(--purple));
    animation: progress linear forwards;
}

@keyframes progress {
    from { transform: translateX(0); }
    to { transform: translateX(-100%); }
}

/* ===== THEME OVERRIDES ===== */
.kanji-learning-wrapper button,
.kanji-learning-wrapper .button,
.kanji-learning-wrapper input[type="button"],
.kanji-learning-wrapper input[type="submit"] {
    background-color: transparent !important;
}

.kanji-learning-wrapper button:hover,
.kanji-learning-wrapper .button:hover {
    background-color: var(--bg-light) !important;
}

.jlpt-btn {
    background-color: var(--bg-white) !important;
}

.jlpt-btn:hover {
    background-color: var(--bg-light) !important;
}

.jlpt-btn.active {
    background-color: var(--bg-green) !important;
}

.lesson-btn {
    background-color: var(--bg-white) !important;
}

.lesson-btn:hover {
    background-color: rgba(8, 145, 178, 0.1) !important;
}

.lesson-btn.active {
    background-color: var(--lesson-active) !important;
}

.lesson-btn.completed {
    background-color: var(--lesson-complete) !important;
}

.btn-control {
    background-color: transparent !important;
}

.btn-control:hover {
    background-color: var(--bg-light) !important;
}

.btn-control.active {
    background-color: var(--bg-green) !important;
}

#btn-complete-lesson {
    background-color: var(--lesson-complete) !important;
}

#btn-complete-lesson:hover {
    background-color: var(--success) !important;
}

.btn-primary,
.btn-secondary {
    background-color: transparent !important;
}

.btn-primary:hover {
    background-color: var(--bg-light) !important;
}

.option-button {
    background-color: var(--bg-white) !important;
}

.option-button:hover:not(:disabled) {
    background-color: var(--bg-light) !important;
}

.option-button.selected {
    background-color: var(--bg-orange) !important;
}

.option-button.correct {
    background-color: #f0fdf4 !important;
}

.option-button.wrong {
    background-color: #fef2f2 !important;
}

.kanji-tab {
    background-color: transparent !important;
}

.kanji-tab:hover {
    background-color: var(--bg-light) !important;
}

.kanji-tab.active {
    background-color: var(--bg-purple) !important;
}

.hidden {
    display: none !important;
}

.loading {
    position: relative;
    opacity: 0.7;
    pointer-events: none;
}

.loading::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 30px;
    height: 30px;
    margin: -15px 0 0 -15px;
    border: 3px solid var(--border-light);
    border-top: 3px solid var(--warning);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

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

.kanji-empty,
#no-results {
    text-align: center;
    padding: 40px;
    color: var(--text-secondary);
}

.kanji-empty {
    padding: 60px 20px;
}

.practice-result,
.quiz-feedback,
#btn-next-practice,
#btn-next-quiz {
    display: none !important;
}

/* CSS cho header với logo - Updated for better spacing */
.kanji-header {
    position: relative;
    padding: 20px;
    text-align: center;
    max-width: 100%;
}

.header-with-logos {
    display: flex;
    align-items: center;
    justify-content: space-between; /* Thay đổi từ center sang space-between */
    width: 100%;
    margin-bottom: 20px;
    position: relative;
}

.header-logo {
    height: 60px;
    width: auto;
    object-fit: contain;
    flex-shrink: 0; /* Không cho logo bị co lại */
}

.logo-left {
    margin-left: 20px; /* Đẩy sát rìa trái */
    margin-right: auto; /* Tự động căn chỉnh */
    animation: fadeInLeft 0.5s ease-in;
}

.logo-right {
    margin-right: 0; /* Đẩy sát rìa phải */
    margin-left: auto; /* Tự động căn chỉnh */
    animation: fadeInRight 0.5s ease-in;
}

.header-content {
    flex: 0 1 auto;
    text-align: center;
    position: absolute; /* Đặt position absolute */
    left: 50%; /* Căn giữa hoàn hảo */
    transform: translateX(-50%);
    width: auto;
    max-width: 60%; /* Giới hạn chiều rộng để không đè lên logo */
}

.header-content h2 {
    margin: 0 0 10px 0;
    font-size: 28px;
    color: #333;
    white-space: nowrap; /* Không xuống dòng */
}

.header-content p {
    margin: 0;
    font-size: 16px;
    color: #666;
    white-space: nowrap; /* Không xuống dòng */
}

/* Animation */
@keyframes fadeInLeft {
    from {
        opacity: 0;
        transform: translateX(-30px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

@keyframes fadeInRight {
    from {
        opacity: 0;
        transform: translateX(30px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

/* Container wrapper nếu cần giới hạn chiều rộng tối đa */
.kanji-learning-wrapper {
    position: relative;
}

.kanji-learning-container {
    max-width: 1400px; /* Có thể điều chỉnh */
    margin: 0 auto;
    padding: 0 20px; /* Padding hai bên để logo không sát mép màn hình */
}

/* ===== RESPONSIVE DESIGN ===== */
@media (max-width: 1024px) {
    .option-button.short-content {
        flex: 0 1 calc(33.333% - 12px);
    }
    
    .flashcard-container {
        max-width: 100%;
        padding: 0 20px;
    }
    
    .lesson-progress-grid {
        grid-template-columns: repeat(auto-fill, minmax(120px, 1fr));
    }
    
    .lesson-menu-grid {
        grid-template-columns: repeat(3, 1fr);
    }
        .header-logo {
        height: 50px;
    }
    
    .header-content {
        max-width: 50%;
    }
    
    .header-content h2 {
        font-size: 24px;
    }
}

@media (max-width: 768px) {
    .kanji-learning-container {
        padding: 15px;
    }
    
    .kanji-header {
        padding: 20px 15px;
    }
    
    .kanji-header h2 {
        font-size: 24px;
    }
    
    #sound-toggle {
        position: static;
        display: block;
        margin: 15px auto 0;
        width: auto;
        max-width: 150px;
    }
    
    .lesson-selector {
        justify-content: flex-start;
        max-height: 200px;
        overflow-y: auto;
        padding: 10px;
    }
    
    .lesson-btn {
        flex: 0 1 calc(50% - 8px);
        min-width: 120px;
        font-size: 12px;
    }
    
    .lesson-progress-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .lesson-menu-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .lesson-menu-content {
        padding: 20px;
        width: 95%;
    }
    
    .kanji-tabs {
        flex-direction: column;
    }
    
    .kanji-tab {
        width: 100%;
    }
    
    .kanji-tab-content {
        min-height: 400px;
        padding: 20px 15px;
    }
    
    .kanji-grid {
        grid-template-columns: repeat(auto-fill, minmax(130px, 1fr));
        gap: 12px;
    }
    
    .flashcard-container {
        max-width: 100%;
    }
    
    .vocab-container .flashcard {
        height: 350px;
    }
    
    .flashcard-arrow {
        width: 38px;
        height: 38px;
        opacity: 0.7;
    }
    
    .flashcard-arrow-left {
        left: 8px;
    }
    
    .flashcard-arrow-right {
        right: 8px;
    }
    
    .flashcard-arrow svg {
        width: 20px;
        height: 20px;
    }
    
    .card-front,
    .card-back {
        padding: 25px 55px;
    }
    
    .flashcard-kanji-display .kanji-text {
        font-size: 100px;
    }
    
    .flashcard-kanji-display .kanji-svg-large {
        width: 200px;
        height: 200px;
    }
    
    .flashcard-hanviet { font-size: 28px; }
    .flashcard-meaning { font-size: 22px; }
    .flashcard-explain { font-size: 14px; padding: 0 15px; }
    
    .flashcard-on-kun {
        font-size: 14px;
        flex-direction: column;
        gap: 8px;
        padding: 8px 15px;
    }
    
    .flashcard-on-kun div:first-child::after {
        display: none;
    }
    
    .practice-options,
    .quiz-options {
        gap: 10px;
    }
    
    .option-button {
        font-size: 18px;
        padding: 12px 16px;
    }
    
    .option-button.short-content {
        flex: 0 1 calc(50% - 10px);
        min-width: 70px;
    }
    
    .option-button.medium-content,
    .option-button.long-content {
        flex: 0 1 100%;
    }
    
    .quiz-mode-selector {
        flex-direction: column;
        gap: 12px;
    }
    
    .stats-grid {
        grid-template-columns: 1fr;
    }
    
    .result-stats {
        grid-template-columns: 1fr;
    }
    
    .kanji-toast-container {
        left: 10px;
        right: 10px;
       bottom: 10px;
   }
   
   .kanji-toast-notification {
       min-width: auto;
       max-width: 100%;
       transform: translateY(100px);
   }
   
   .kanji-toast-notification.show {
       transform: translateY(0);
   }
   
@media (max-width: 768px) {
    .header-with-logos {
        padding: 10px 0;
    }
    
    .header-logo {
        height: 40px;
    }
    
    .header-content {
        position: static;
        transform: none;
        max-width: 100%;
        padding: 0 10px;
    }
    
    .header-content h2 {
        font-size: 20px;
        white-space: normal;
    }
    
    .header-content p {
        font-size: 14px;
        white-space: normal;
    }
}
}

@media (max-width: 480px) {
   .kanji-grid {
       grid-template-columns: repeat(auto-fill, minmax(110px, 1fr));
   }
   
   .kanji-main {
       font-size: 42px;
       height: 70px;
   }
   
   .lesson-btn {
       flex: 0 1 100%;
       margin: 2px 0;
   }
   
   .lesson-progress-grid {
       grid-template-columns: 1fr;
   }
   
   .lesson-menu-grid {
       grid-template-columns: 1fr;
   }
   
   .lesson-menu-item {
       padding: 12px;
   }
   
   .vocab-container .flashcard {
       height: 300px;
   }
   
   .flashcard-arrow {
       width: 34px;
       height: 34px;
   }
   
   .flashcard-arrow-left {
       left: 5px;
   }
   
   .flashcard-arrow-right {
       right: 5px;
   }
   
   .flashcard-arrow svg {
       width: 18px;
       height: 18px;
   }
   
   .card-front,
   .card-back {
       padding: 20px 50px;
   }
   
   .flashcard-kanji-display .kanji-text {
       font-size: 80px;
   }
   
   .flashcard-kanji-display .kanji-svg-large {
       width: 160px;
       height: 160px;
   }
   
   .flashcard-hanviet { font-size: 24px; }
   .flashcard-meaning { font-size: 18px; padding: 8px 15px; }
   .flashcard-explain { font-size: 13px; padding: 0 10px; }
   
   .flashcard-examples {
       font-size: 12px;
       padding: 10px;
   }
   
   .flashcard-controls {
       flex-wrap: wrap;
   }
   
   .btn-control {
       flex: 1;
       min-width: 100px;
   }
   
   .option-button.short-content {
       flex: 0 1 calc(50% - 8px);
       min-width: 60px;
       font-size: 16px;
       padding: 10px 8px;
   }
    .header-with-logos {
        position: relative;
        min-height: 100px;
        padding-top: 50px;
    }
    
    .header-logo {
        position: absolute;
        height: 35px;
        top: 10px;
    }
    
    .logo-left {
        left: 10px;
        margin: 0;
    }
    
    .logo-right {
        right: 10px;
        margin: 0;
    }
    
    .header-content {
        position: static;
        margin-top: 10px;
    }
}

/* Print Styles */
@media print {
   .kanji-header,
   .kanji-tabs,
   .flashcard-controls,
   .practice-controls,
   .quiz-controls,
   #sound-toggle,
   .kanji-toast-container,
   .lesson-selector,
   .lesson-quick-nav,
   .btn-clear-lesson,
   .flashcard-settings {
       display: none;
   }
   
   .kanji-card {
       break-inside: avoid;
       page-break-inside: avoid;
   }
   
   .lesson-menu-modal {
       display: none !important;
   }
}

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

/* High contrast mode support */
@media (prefers-contrast: high) {
   .kanji-card {
       border-width: 3px;
   }
   
   .lesson-btn,
   .jlpt-btn {
       border-width: 3px;
   }
   
   .card-front,
   .card-back {
       border-width: 4px;
   }
}

/* Dark mode support (optional) */
@media (prefers-color-scheme: dark) {
   /* Can add dark mode styles here if needed */
}

/* ===== UTILITIES ===== */
.text-center { text-align: center !important; }
.text-left { text-align: left !important; }
.text-right { text-align: right !important; }

.mt-0 { margin-top: 0 !important; }
.mt-1 { margin-top: 0.5rem !important; }
.mt-2 { margin-top: 1rem !important; }
.mt-3 { margin-top: 1.5rem !important; }
.mt-4 { margin-top: 2rem !important; }

.mb-0 { margin-bottom: 0 !important; }
.mb-1 { margin-bottom: 0.5rem !important; }
.mb-2 { margin-bottom: 1rem !important; }
.mb-3 { margin-bottom: 1.5rem !important; }
.mb-4 { margin-bottom: 2rem !important; }

.p-0 { padding: 0 !important; }
.p-1 { padding: 0.5rem !important; }
.p-2 { padding: 1rem !important; }
.p-3 { padding: 1.5rem !important; }
.p-4 { padding: 2rem !important; }

.w-100 { width: 100% !important; }
.h-100 { height: 100% !important; }

.d-none { display: none !important; }
.d-block { display: block !important; }
.d-flex { display: flex !important; }
.d-inline { display: inline !important; }
.d-inline-block { display: inline-block !important; }

.flex-row { flex-direction: row !important; }
.flex-column { flex-direction: column !important; }
.flex-wrap { flex-wrap: wrap !important; }
.flex-nowrap { flex-wrap: nowrap !important; }

.justify-content-start { justify-content: flex-start !important; }
.justify-content-end { justify-content: flex-end !important; }
.justify-content-center { justify-content: center !important; }
.justify-content-between { justify-content: space-between !important; }
.justify-content-around { justify-content: space-around !important; }

.align-items-start { align-items: flex-start !important; }
.align-items-end { align-items: flex-end !important; }
.align-items-center { align-items: center !important; }
.align-items-baseline { align-items: baseline !important; }
.align-items-stretch { align-items: stretch !important; }

.position-relative { position: relative !important; }
.position-absolute { position: absolute !important; }
.position-fixed { position: fixed !important; }
.position-static { position: static !important; }

.overflow-hidden { overflow: hidden !important; }
.overflow-auto { overflow: auto !important; }
.overflow-scroll { overflow: scroll !important; }
.overflow-visible { overflow: visible !important; }

/* ===== END OF STYLES ===== */