/* CSS Variables for Light/Dark Mode */
:root {
    /* Light Mode Colors */
    --bg-primary: #f0f8ff;
    --bg-secondary: #ffffff;
    --bg-accent: #e6f3ff;
    --text-primary: #2c3e50;
    --text-secondary: #34495e;
    --accent-color: #3498db;
    --accent-hover: #2980b9;
    --success-color: #27ae60;
    --warning-color: #f39c12;
    --error-color: #e74c3c;
    --card-bg: #ffffff;
    --card-shadow: rgba(0, 0, 0, 0.1);
    --border-color: #bdc3c7;
    
    /* Child-friendly colors */
    --color-pink: #ff6b9d;
    --color-purple: #9b59b6;
    --color-blue: #3498db;
    --color-green: #2ecc71;
    --color-yellow: #f1c40f;
    --color-orange: #e67e22;
    --color-red: #e74c3c;
    --color-cyan: #1abc9c;
}

[data-theme="dark"] {
    /* Dark Mode Colors */
    --bg-primary: #1a1a2e;
    --bg-secondary: #16213e;
    --bg-accent: #0f3460;
    --text-primary: #ecf0f1;
    --text-secondary: #bdc3c7;
    --accent-color: #3498db;
    --accent-hover: #5dade2;
    --success-color: #27ae60;
    --warning-color: #f39c12;
    --error-color: #e74c3c;
    --card-bg: #2c3e50;
    --card-shadow: rgba(0, 0, 0, 0.3);
    --border-color: #34495e;
}

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

body {
    font-family: 'Fredoka', cursive;
    background: linear-gradient(135deg, var(--bg-primary) 0%, var(--bg-accent) 100%);
    color: var(--text-primary);
    min-height: 100vh;
    transition: all 0.3s ease;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
}

/* Header Styles */
.header {
    background: var(--card-bg);
    border-radius: 20px;
    box-shadow: 0 8px 32px var(--card-shadow);
    margin-bottom: 30px;
    padding: 20px;
    -webkit-backdrop-filter: blur(10px);
    backdrop-filter: blur(10px);
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 20px;
}

.logo {
    font-size: 2.5rem;
    font-weight: 700;
    background: linear-gradient(45deg, var(--color-pink), var(--color-purple), var(--color-blue));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.1);
}

.theme-toggle {
    position: relative;
    padding: 5px;
}

.theme-switch {
    position: relative;
    display: inline-block;
    width: 64px;
    height: 34px;
    margin: 0;
}

.theme-input {
    opacity: 0;
    width: 0;
    height: 0;
}

.theme-slider {
    position: absolute;
    cursor: pointer;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(45deg, var(--color-blue), var(--color-cyan));
    border-radius: 34px;
    transition: 0.4s;
    padding: 4px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    box-shadow: inset 0 2px 4px rgba(0,0,0,0.2), 0 4px 15px rgba(0,0,0,0.15);
}

.theme-slider:before {
    content: "";
    position: absolute;
    height: 26px;
    width: 26px;
    left: 4px;
    bottom: 4px;
    background-color: white;
    transition: 0.4s;
    border-radius: 50%;
    z-index: 2;
    box-shadow: 0 2px 4px rgba(0,0,0,0.2);
}

.theme-input:checked + .theme-slider {
    background: linear-gradient(45deg, var(--color-purple), var(--color-pink));
}

.theme-input:checked + .theme-slider:before {
    transform: translateX(30px);
}

.theme-icon {
    font-size: 16px;
    line-height: 26px;
    transition: opacity 0.2s ease;
    z-index: 1;
}

.theme-icon.sun {
    margin-left: 6px;
}

.theme-icon.moon {
    margin-right: 6px;
    opacity: 0.4;
}

.theme-input:checked + .theme-slider .theme-icon.sun {
    opacity: 0.4;
}

.theme-input:checked + .theme-slider .theme-icon.moon {
    opacity: 1;
}

/* Hover effect */
.theme-switch:hover .theme-slider {
    transform: scale(1.05);
    box-shadow: inset 0 2px 4px rgba(0,0,0,0.2), 0 6px 20px rgba(0,0,0,0.2);
}

/* Navigation Styles */
.navigation {
    background: var(--card-bg);
    border-radius: 20px;
    box-shadow: 0 8px 32px var(--card-shadow);
    margin-bottom: 30px;
    padding: 30px;
    -webkit-backdrop-filter: blur(10px);
    backdrop-filter: blur(10px);
}

.nav-content h2 {
    font-size: 1.8rem;
    margin-bottom: 20px;
    color: var(--text-primary);
    text-align: center;
}

.topic-buttons {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 15px;
}

.topic-btn {
    background: linear-gradient(45deg, var(--color-blue), var(--color-cyan));
    color: white;
    border: none;
    border-radius: 15px;
    padding: 15px 20px;
    font-size: 1.1rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
    font-family: 'Fredoka', cursive;
}

.topic-btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 6px 20px rgba(0, 0, 0, 0.3);
}

.topic-btn.active {
    background: linear-gradient(45deg, var(--color-pink), var(--color-purple));
    transform: scale(1.05);
}

/* Game Selection Styles */
.game-selection {
    background: var(--card-bg);
    border-radius: 20px;
    box-shadow: 0 8px 32px var(--card-shadow);
    margin-bottom: 30px;
    padding: 30px;
    -webkit-backdrop-filter: blur(10px);
    backdrop-filter: blur(10px);
    text-align: center;
}

.game-selection h2 {
    font-size: 1.8rem;
    margin-bottom: 20px;
    color: var(--text-primary);
}

.game-buttons {
    display: flex;
    justify-content: center;
    gap: 30px;
    flex-wrap: wrap;
}

.game-btn {
    background: linear-gradient(45deg, var(--color-green), var(--color-cyan));
    color: white;
    border: none;
    border-radius: 20px;
    padding: 20px 40px;
    font-size: 1.3rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 6px 20px rgba(0, 0, 0, 0.2);
    font-family: 'Fredoka', cursive;
}

.game-btn:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.3);
}

.game-btn.active {
    background: linear-gradient(45deg, var(--color-orange), var(--color-red));
    transform: scale(1.1);
}

/* Game Area Styles */
.game-area {
    background: var(--card-bg);
    border-radius: 20px;
    box-shadow: 0 8px 32px var(--card-shadow);
    padding: 30px;
    -webkit-backdrop-filter: blur(10px);
    backdrop-filter: blur(10px);
    min-height: 400px;
}

.game-container {
    width: 100%;
}

.welcome-message {
    text-align: center;
    padding: 60px 20px;
}

.welcome-message h2 {
    font-size: 2.5rem;
    margin-bottom: 20px;
    background: linear-gradient(45deg, var(--color-pink), var(--color-purple), var(--color-blue));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.welcome-message p {
    font-size: 1.3rem;
    color: var(--text-secondary);
}

/* Game Header Styles */
.game-header {
    text-align: center;
    margin-bottom: 30px;
}

.game-header h2 {
    font-size: 2rem;
    margin-bottom: 10px;
    background: linear-gradient(45deg, var(--color-pink), var(--color-purple), var(--color-blue));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.game-header p {
    font-size: 1.2rem;
    color: var(--text-secondary);
    margin-bottom: 20px;
}

.game-controls {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 20px;
    max-width: 600px;
    margin: 0 auto;
}

.game-stats {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-primary);
    background: var(--bg-accent);
    padding: 10px 20px;
    border-radius: 25px;
    box-shadow: 0 2px 10px var(--card-shadow);
}

.reset-btn {
    background: linear-gradient(45deg, var(--color-orange), var(--color-red));
    color: white;
    border: none;
    border-radius: 25px;
    padding: 12px 24px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
    font-family: 'Fredoka', cursive;
}

.reset-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(0, 0, 0, 0.3);
}

.reset-btn:active {
    transform: translateY(0);
}

/* Flashcard Styles */
.flashcards-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    padding: 20px 0;
}

.flashcard {
    background: var(--card-bg);
    border-radius: 15px;
    padding: 30px;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px var(--card-shadow);
    border: 3px solid transparent;
    min-height: 150px;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    overflow: hidden;
}

.flashcard:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 25px var(--card-shadow);
    border-color: var(--accent-color);
}

.flashcard.flipped {
    background: linear-gradient(45deg, var(--color-pink), var(--color-purple));
    color: white;
    transform: rotateY(180deg);
}

.flashcard-content {
    font-size: 1.4rem;
    font-weight: 600;
    transition: all 0.3s ease;
}

.flashcard.flipped .flashcard-content {
    transform: rotateY(180deg);
}

/* Matching Game Styles */
.matching-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 15px;
    padding: 20px 0;
    max-width: 800px;
    margin: 0 auto;
}

.matching-card {
    background: var(--card-bg);
    border-radius: 15px;
    padding: 20px;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px var(--card-shadow);
    border: 3px solid transparent;
    min-height: 120px;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    overflow: hidden;
}

.matching-card:hover {
    transform: translateY(-3px);
    box-shadow: 0 6px 20px var(--card-shadow);
    border-color: var(--accent-color);
}

.matching-card.flipped {
    background: linear-gradient(45deg, var(--color-blue), var(--color-cyan));
    color: white;
    transform: rotateY(180deg);
}

.matching-card.disabled {
    opacity: 0.6;
    cursor: not-allowed;
    pointer-events: none;
}

.matching-card.matched {
    animation: shrinkDisappear 0.6s ease-in-out forwards;
    pointer-events: none;
}

.matching-card-content {
    font-size: 1.2rem;
    font-weight: 600;
    transition: all 0.3s ease;
}

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

/* Sort Ninja Game Styles */
.category-selection {
    text-align: center;
    margin: 30px 0;
}

.category-counter {
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--text-primary);
    background: var(--bg-accent);
    padding: 8px 14px;
    border-radius: 20px;
    display: inline-block;
    margin-bottom: 12px;
    box-shadow: 0 2px 10px var(--card-shadow);
}

.category-selection h3 {
    font-size: 1.5rem;
    margin-bottom: 20px;
    color: var(--text-primary);
}

.category-checkboxes {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 15px;
    margin-bottom: 30px;
    max-width: 800px;
    margin-left: auto;
    margin-right: auto;
}

.category-checkbox {
    display: flex;
    align-items: center;
    padding: 15px;
    background: var(--bg-accent);
    border-radius: 15px;
    cursor: pointer;
    transition: all 0.3s ease;
    border: 2px solid transparent;
}

.category-checkbox:hover {
    background: var(--accent-color);
    color: white;
    transform: translateY(-2px);
}

.category-checkbox input[type="checkbox"] {
    margin-right: 10px;
    transform: scale(1.2);
}

.checkbox-label {
    font-weight: 500;
    font-size: 1.1rem;
}

.start-sort-btn {
    background: linear-gradient(45deg, var(--color-green), var(--color-cyan));
    color: white;
    border: none;
    border-radius: 25px;
    padding: 15px 30px;
    font-size: 1.2rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
    font-family: 'Fredoka', cursive;
}

.start-sort-btn:hover:not(:disabled) {
    transform: translateY(-3px);
    box-shadow: 0 6px 20px rgba(0, 0, 0, 0.3);
}

.start-sort-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none;
}

.tooltip-container {
    display: inline-block;
    position: relative;
    margin-top: 12px;
}

.tooltip-text {
    display: block;
    font-size: 0.95rem;
    color: var(--text-secondary);
    background: transparent;
    padding: 6px 10px;
    border-radius: 12px;
    margin-top: 8px;
    transition: all 0.2s ease;
}

/* Optional hover bubble for tooltip (visible on hover) */
.tooltip-container .tooltip-bubble {
    visibility: hidden;
    opacity: 0;
    position: absolute;
    bottom: 120%;
    left: 50%;
    transform: translateX(-50%);
    background: var(--text-primary);
    color: white;
    padding: 8px 12px;
    border-radius: 8px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.2);
    white-space: nowrap;
}

.tooltip-container:hover .tooltip-bubble {
    visibility: visible;
    opacity: 1;
}

.sort-stats {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--text-primary);
    background: var(--bg-accent);
    padding: 10px 20px;
    border-radius: 25px;
    box-shadow: 0 2px 10px var(--card-shadow);
    display: inline-block;
}

.selected-categories-info {
    margin-top: 15px;
}

.selected-categories-info p {
    font-size: 1rem;
    color: var(--text-secondary);
    background: var(--bg-accent);
    padding: 8px 16px;
    border-radius: 20px;
    display: inline-block;
}

.sort-game-area {
    display: flex;
    flex-direction: column;
    gap: 30px;
    margin-top: 20px;
}

.sort-cards-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
    gap: 15px;
    padding: 20px;
    background: var(--bg-accent);
    border-radius: 20px;
    min-height: 150px;
}

.sort-card {
    background: var(--card-bg);
    border-radius: 15px;
    padding: 15px;
    text-align: center;
    cursor: grab;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px var(--card-shadow);
    border: 3px solid transparent;
    font-weight: 600;
    font-size: 1rem;
    -webkit-user-select: none;
    user-select: none;
}

.sort-card:hover {
    transform: translateY(-3px);
    box-shadow: 0 6px 20px var(--card-shadow);
    border-color: var(--accent-color);
}

.sort-card.dragging {
    opacity: 0.5;
    transform: rotate(5deg);
    cursor: grabbing;
}

.sort-boxes-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    padding: 20px;
}

.sort-box {
    background: var(--card-bg);
    border-radius: 20px;
    padding: 30px;
    text-align: center;
    border: 3px dashed var(--border-color);
    transition: all 0.3s ease;
    min-height: 120px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.sort-box h4 {
    font-size: 1.3rem;
    color: var(--text-primary);
    margin: 0;
}

.sort-box.drag-over {
    border-color: var(--accent-color);
    background: var(--bg-accent);
    transform: scale(1.05);
}

/* Hangman Styles */
.hangman-area {
    display: flex;
    flex-direction: column;
    gap: 18px;
    align-items: center;
}

.hangman-stats {
    display: flex;
    gap: 20px;
    font-weight: 600;
    color: var(--text-primary);
}

.hangman-word {
    display: flex;
    gap: 8px;
    font-size: 1.6rem;
    font-weight: 800;
    letter-spacing: 4px;
    flex-wrap: wrap;
    justify-content: center;
}

.hangman-letter {
    display: inline-block;
    min-width: 18px;
    text-align: center;
    padding: 6px 8px;
    border-radius: 6px;
    background: var(--bg-accent);
    color: var(--text-primary);
}

.hangman-keyboard {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(35px, 1fr));
    gap: 8px;
    width: 100%;
    max-width: 720px;
    margin: 20px auto;
    padding: 10px;
    background: var(--bg-accent);
    border-radius: 15px;
    justify-content: center;
}

.hangman-key {
    background: var(--card-bg);
    border: 2px solid var(--border-color);
    padding: 12px;
    border-radius: 8px;
    font-weight: 700;
    cursor: pointer;
    font-size: 1.2rem;
    min-width: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.2s ease;
}

.hangman-key:hover:not(:disabled) {
    transform: translateY(-2px);
    background: var(--accent-color);
    color: white;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
}

.hangman-key:disabled {
    opacity: 0.45;
    cursor: not-allowed;
}

.hangman-controls {
    display: flex;
    gap: 12px;
    margin-top: 6px;
}

.hangman-stats-and-drawing {
    display: flex;
    gap: 18px;
    align-items: center;
    justify-content: center;
    flex-wrap: wrap;
}

.hint-area {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 12px;
    margin: 12px 0;
}

.hint-btn {
    background: linear-gradient(45deg, var(--color-blue), var(--color-cyan));
    color: white;
    border: none;
    border-radius: 20px;
    padding: 8px 16px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    font-family: 'Fredoka', cursive;
}

.hint-btn:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
}

.hint-btn:disabled {
    opacity: 0.7;
    cursor: not-allowed;
    background: linear-gradient(45deg, var(--color-green), var(--color-cyan));
}

.hint-text {
    font-size: 1.2rem;
    color: var(--text-secondary);
    margin: 0;
    opacity: 1;
    transform: translateY(0);
    transition: all 0.3s ease-in-out;
    /* Keep hint in the normal document flow to avoid layout shifts on some servers/browsers */
    position: static;
    display: block;
    background: var(--bg-accent);
    padding: 8px 16px;
    border-radius: 12px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    z-index: 1;
}

.hint-text.hidden {
    opacity: 0;
    transform: translateY(-10px);
    height: 0;
    margin: 0;
    pointer-events: none;
    display: none !important;
}

.hangman-drawing {
    width: 220px;
    height: 260px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.hangman-svg {
    width: 180px;
    height: 220px;
}

.hang-part {
    stroke: var(--text-primary);
    stroke-width: 4;
    fill: none;
    /* hide parts by default */
    display: none;
}

/* When JS marks a part visible, use this class rather than inline !important styles */
.hang-part.visible {
    display: block;
}

/* Row helper for keyboard rows (avoid inline styles in generated HTML) */
.hangman-row {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(35px, 1fr));
    gap: 8px;
    width: 100%;
}

/* Animations */
@keyframes shrinkDisappear {
    0% {
        opacity: 1;
        transform: scale(1);
    }
    100% {
        opacity: 0;
        transform: scale(0);
    }
}

@keyframes slideBack {
    0% {
        transform: translateX(0);
    }
    50% {
        transform: translateX(-10px);
    }
    100% {
        transform: translateX(0);
    }
}

@keyframes flipToBlank {
    0% {
        transform: rotateY(0deg);
    }
    100% {
        transform: rotateY(90deg);
    }
}

@keyframes flipFromBlank {
    0% {
        transform: rotateY(90deg);
    }
    100% {
        transform: rotateY(180deg);
    }
}

@keyframes fadeInText {
    0% {
        opacity: 0;
    }
    100% {
        opacity: 1;
    }
}

.flashcard.flipping-first-half {
    animation: flipToBlank 0.3s ease-in forwards;
}

.flashcard.flipping-second-half {
    animation: flipFromBlank 0.3s ease-out forwards;
}

.flashcard-content.fade-in {
    animation: fadeInText 0.2s ease-out forwards;
}

/* Hide content during flip */
.flashcard.flipping-first-half .flashcard-content {
    opacity: 0;
    transition: opacity 0.15s ease-in;
}

/* Footer Styles */
.footer {
    text-align: center;
    margin-top: 30px;
    padding: 20px;
    color: var(--text-secondary);
    font-size: 1.1rem;
}

/* Responsive Design */
@media (max-width: 768px) {
    .container {
        padding: 10px;
    }
    
    .logo {
        font-size: 2rem;
    }
    
    .header-content {
        flex-direction: column;
        text-align: center;
    }
    
    .topic-buttons {
        grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    }
    
    .game-buttons {
        flex-direction: column;
        align-items: center;
    }
    
    .game-btn {
        width: 100%;
        max-width: 300px;
    }
    
    .flashcards-grid {
        grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    }
    
    .matching-grid {
        grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
    }
    
    .game-controls {
        flex-direction: column;
        text-align: center;
    }
    
    .reset-btn {
        width: 100%;
        max-width: 200px;
    }
    
    .category-checkboxes {
        grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    }
    
    .sort-cards-container {
        grid-template-columns: repeat(auto-fit, minmax(100px, 1fr));
    }
    
    .sort-boxes-container {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .logo {
        font-size: 1.5rem;
    }
    
    .welcome-message h2 {
        font-size: 2rem;
    }
    
    .welcome-message p {
        font-size: 1.1rem;
    }
    
    .flashcard {
        min-height: 120px;
        padding: 20px;
    }
    
    .matching-card {
        min-height: 100px;
        padding: 15px;
    }
}