/* CSS Custom Properties */
:root {
    /* Colors */
    --primary-blue: #3498db;
    --primary-blue-dark: #2980b9;
    --success-green: #2ecc71;
    --success-green-dark: #27ae60;
    --danger-red: #e74c3c;
    --danger-red-dark: #c0392b;
    --google-red: #db4437;
    --google-red-dark: #c23321;
    --text-primary: #333;
    --text-secondary: #666;
    --text-light: #777;
    --border-light: #ddd;
    --border-lighter: #eee;
    --bg-light: #f8f9fa;
    --bg-lighter: #fafafa;
    --shadow-light: rgba(0, 0, 0, 0.1);
    --shadow-medium: rgba(0, 0, 0, 0.3);
    --overlay: rgba(0, 0, 0, 0.5);
    
    /* Spacing */
    --spacing-xs: 5px;
    --spacing-sm: 10px;
    --spacing-md: 15px;
    --spacing-lg: 20px;
    --spacing-xl: 30px;
    
    /* Typography */
    --font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    --font-size-sm: 12px;
    --font-size-base: 14px;
    --font-size-md: 16px;
    --font-size-lg: 18px;
    --font-size-xl: 24px;
    --font-size-xxl: 32px;
    
    /* Border Radius */
    --radius-sm: 4px;
    --radius-md: 5px;
    --radius-lg: 8px;
    --radius-xl: 10px;
    
    /* Transitions */
    --transition-fast: 0.2s;
    --transition-normal: 0.3s;
}

/* Global Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: var(--font-family);
    line-height: 1.6;
    color: var(--text-primary);
    background-color: white;
}

#app {
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--spacing-lg);
}

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

.fadeIn {
    animation: fadeIn 0.5s ease-in;
}

/* Button Styles */
button, .btn, .auth-btn, .action-btn {
    background-color: var(--primary-blue);
    color: white;
    border: none;
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-size: var(--font-size-md);
    font-weight: 500;
    transition: background-color var(--transition-fast);
    text-decoration: none;
    display: inline-block;
    text-align: center;
    line-height: 1.4;
    box-sizing: border-box;
}

button:hover, .btn:hover, .auth-btn:hover {
    background-color: var(--primary-blue-dark);
}

.action-btn {
    padding: var(--spacing-sm) var(--spacing-md);
    font-size: var(--font-size-md);
    margin-right: var(--spacing-sm);
}

.action-btn.small {
    padding: 4px 8px;
    font-size: var(--font-size-sm);
}

.action-btn:hover {
    background-color: var(--success-green-dark);
}

.btn-success, .action-btn {
    background-color: var(--success-green);
}

.btn-danger, .unlock-btn {
    background-color: var(--danger-red);
}

.btn-danger:hover, .unlock-btn:hover {
    background-color: var(--danger-red-dark);
}

.google-btn {
    background-color: var(--google-red);
    width: 100%;
    margin-top: var(--spacing-sm);
}

.google-btn:hover {
    background-color: var(--google-red-dark);
}

button:disabled {
    background-color: #f5f5f5;
    color: #ccc;
    border-color: var(--border-light);
    cursor: not-allowed;
    transform: none;
}

.insufficient-points {
    background-color: #95a5a6;
    cursor: not-allowed;
    opacity: 0.7;
}

.insufficient-points:hover {
    background-color: #7f8c8d;
}

/* Header Styles */
header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-lg);
    border-bottom: 2px solid var(--border-lighter);
    margin-bottom: var(--spacing-xl);
}

.header-left {
    display: flex;
    align-items: center;
    gap: var(--spacing-xl);
}

.nav-menu {
    display: flex;
    gap: var(--spacing-lg);
}

.nav-link {
    color: var(--primary-blue);
    text-decoration: none;
    font-weight: 600;
    font-size: 1.1rem;
    padding: var(--spacing-sm) var(--spacing-lg);
    border-radius: var(--radius-md);
    transition: all var(--transition-normal) ease;
}

.nav-link:hover, .nav-link.active {
    background: var(--primary-blue);
    color: white;
    transform: translateY(-1px);
}

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

.logo {
    width: 150px;
    height: auto;
}

header h1 {
    color: var(--primary-blue);
    font-size: 2.5rem;
}

#user-info {
    background-color: white;
    padding: var(--spacing-sm) var(--spacing-lg);
    border-radius: var(--radius-lg);
    box-shadow: 0 2px 5px var(--shadow-light);
}

#user-info p {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    margin: var(--spacing-xs) 0;
    font-weight: 500;
}

#user-level, #user-points {
    font-weight: 700;
    color: var(--primary-blue);
}

.auth-buttons {
    margin-top: var(--spacing-sm);
}

.auth-divider {
    text-align: center;
    margin: var(--spacing-lg) 0;
    position: relative;
}

.auth-divider::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 0;
    right: 0;
    height: 1px;
    background-color: var(--border-light);
}

.auth-divider span {
    background-color: white;
    padding: 0 var(--spacing-md);
    color: var(--text-secondary);
    font-size: var(--font-size-base);
}

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

label {
    display: block;
    margin-bottom: var(--spacing-xs);
    font-weight: 500;
    color: #555;
}

input {
    width: 100%;
    padding: var(--spacing-sm);
    border: 1px solid var(--border-light);
    border-radius: var(--radius-sm);
    font-size: var(--font-size-md);
}

input:focus {
    outline: none;
    border-color: #4CAF50;
    box-shadow: 0 0 5px rgba(76, 175, 80, 0.3);
}

.form-buttons {
    display: flex;
    gap: var(--spacing-sm);
    align-items: center;
}

/* Authentication Section */
#auth-section {
    max-width: 500px;
    margin: 0 auto;
    background-color: white;
    padding: var(--spacing-xl);
    border-radius: var(--radius-lg);
    box-shadow: 0 4px 10px var(--shadow-light);
}

#auth-section h2 {
    text-align: center;
    margin-bottom: var(--spacing-lg);
    color: var(--primary-blue);
}

#auth-section p {
    text-align: center;
    margin-top: var(--spacing-lg);
}

#auth-section a {
    color: var(--primary-blue);
    text-decoration: none;
}

#auth-section a:hover {
    text-decoration: underline;
}

/* Tabs */
.tabs {
    display: flex;
    margin-bottom: var(--spacing-lg);
    border-bottom: 1px solid var(--border-light);
}

.tab-btn {
    padding: var(--spacing-sm) var(--spacing-lg);
    background-color: transparent;
    color: var(--text-primary);
    border: none;
    border-bottom: 3px solid transparent;
    margin-right: var(--spacing-sm);
}

.tab-btn.active {
    border-bottom: 3px solid var(--primary-blue);
    color: var(--primary-blue);
}

.tab-content {
    display: none;
    background-color: white;
    padding: var(--spacing-lg);
    border-radius: var(--radius-lg);
    box-shadow: 0 4px 10px var(--shadow-light);
}

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

/* Question Container */
.question-container {
    margin-bottom: var(--spacing-xl);
}

#question-text {
    font-size: 1.2rem;
    margin: var(--spacing-md) 0;
    padding: var(--spacing-md);
    background-color: var(--bg-light);
    border-radius: var(--radius-lg);
    border-left: 4px solid var(--primary-blue);
}

.actions {
    margin-top: var(--spacing-lg);
}

#hint-container {
    margin-top: var(--spacing-md);
    padding: var(--spacing-sm);
    background-color: #fffde7;
    border-radius: var(--radius-sm);
    border-left: 4px solid #ffc107;
}

/* Games Grid */
.games-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: var(--spacing-lg);
}

.game-card {
    background-color: var(--bg-light);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    box-shadow: 0 2px 5px var(--shadow-light);
    transition: transform var(--transition-normal);
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    min-height: 200px;
    position: relative;
    overflow: visible;
}

.game-card:hover {
    transform: translateY(-5px);
}

.game-card h3 {
    color: var(--primary-blue);
    margin-bottom: var(--spacing-sm);
}

.game-card p {
    margin-bottom: var(--spacing-md);
    color: var(--text-secondary);
}

.game-card-content {
    flex-grow: 1;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.game-card-buttons {
    margin-top: auto;
}

.game-card.locked::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(0, 0, 0, 0.05);
    border-radius: var(--radius-lg);
    z-index: 1;
    pointer-events: none;
}

.play-btn {
    position: relative;
    z-index: 100;
    pointer-events: auto;
    background-color: var(--success-green);
}

.play-btn:hover {
    background-color: var(--success-green-dark);
}

.play-btn.hidden {
    display: none !important;
}

/* Feedback Messages */
.feedback {
    padding: var(--spacing-sm) var(--spacing-md);
    margin: var(--spacing-sm) 0;
    border-radius: var(--radius-sm);
    position: fixed;
    top: var(--spacing-lg);
    left: 50%;
    transform: translateX(-50%);
    z-index: 1000;
    min-width: 300px;
    text-align: center;
    box-shadow: 0 4px 6px var(--shadow-light);
}

.success, .message.success {
    background-color: #d4edda;
    color: #155724;
    border-left: 4px solid #28a745;
}

.error, .message.error {
    background-color: #f8d7da;
    color: #721c24;
    border-left: 4px solid #dc3545;
}

.message {
    margin-top: var(--spacing-sm);
    padding: 8px;
    border-radius: var(--radius-sm);
    text-align: center;
    font-size: var(--font-size-base);
}

/* Modal Styles */
.modal {
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: var(--overlay);
    display: flex;
    justify-content: center;
    align-items: center;
}

.modal.hidden {
    display: none;
}

.modal-content {
    background-color: white;
    padding: var(--spacing-xl);
    border-radius: var(--radius-xl);
    box-shadow: 0 4px 20px var(--shadow-medium);
    width: 90%;
    max-width: 400px;
    position: relative;
}

.close {
    position: absolute;
    top: var(--spacing-sm);
    right: var(--spacing-md);
    color: #aaa;
    font-size: 28px;
    font-weight: bold;
    cursor: pointer;
}

.close:hover, .close:focus {
    color: var(--text-primary);
    text-decoration: none;
}

.modal h2 {
    margin-bottom: var(--spacing-lg);
    color: var(--text-primary);
    text-align: center;
}

.modal .auth-btn {
    width: 100%;
    margin-top: var(--spacing-sm);
}

/* Game Container Styles */
.mini-game-container, #sudoku-game, #crossword-game {
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 90%;
    max-width: 500px;
    background-color: white;
    border-radius: var(--radius-xl);
    box-shadow: 0 0 20px var(--shadow-medium);
    z-index: 1000;
    padding: var(--spacing-lg);
    display: flex;
    flex-direction: column;
}

#sudoku-game {
    max-width: 600px;
}

#crossword-game {
    max-width: 800px;
    max-height: 90vh;
    overflow-y: auto;
}

.game-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-lg);
    border-bottom: 1px solid var(--border-lighter);
    padding-bottom: var(--spacing-sm);
}

.game-header h2 {
    margin: 0;
    color: var(--text-primary);
}

#close-game, #close-puzzle-game, #close-speed-game, #close-mines-game, #close-crossword-game, #close-sudoku-game, #close-word-search-game, #close-make24-game {
    background: none;
    border: none;
    font-size: var(--spacing-lg);
    cursor: pointer;
    color: var(--text-light);
}

#close-game:hover, #close-puzzle-game:hover, #close-speed-game:hover, #close-mines-game:hover, #close-crossword-game:hover, #close-sudoku-game:hover {
    color: var(--text-primary);
}

.game-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-lg);
}

/* Game Status and Display */
#game-status, #puzzle-status, #speed-status, #sudoku-status, #crossword-status, #mines-status {
    font-size: var(--font-size-lg);
    font-weight: bold;
    color: var(--text-primary);
    text-align: center;
    width: 100%;
    margin-bottom: var(--spacing-sm);
    padding: var(--spacing-sm);
    background-color: var(--bg-light);
    border-radius: var(--radius-lg);
    display: flex;
    justify-content: space-between;
}

#number-display, #puzzle-display, #speed-problem {
    font-size: var(--font-size-xxl);
    font-weight: bold;
    letter-spacing: 3px;
    min-height: 40px;
    color: #2c3e50;
    background-color: var(--bg-light);
    padding: var(--spacing-md) var(--spacing-xl);
    border-radius: var(--radius-lg);
    width: 80%;
    text-align: center;
}

#input-container, #puzzle-input-container, #speed-input-container {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
    width: 80%;
}

#number-input, #puzzle-input, #speed-input {
    padding: 12px;
    font-size: var(--font-size-lg);
    border: 2px solid var(--border-light);
    border-radius: var(--radius-md);
    text-align: center;
    letter-spacing: 2px;
}

#submit-answer, #submit-puzzle, #submit-speed, #start-speed-game {
    padding: 12px;
    font-size: var(--font-size-md);
    font-weight: bold;
}

#game-message, #puzzle-message, #speed-message, #sudoku-message, #crossword-message, #mines-message, #word-search-message, #make24-message {
    font-size: var(--font-size-md);
    text-align: center;
    min-height: 50px;
    padding: var(--spacing-sm);
    width: 80%;
    margin: var(--spacing-md) auto;
    background-color: var(--bg-light);
    border-radius: var(--radius-lg);
    font-weight: bold;
    transition: color var(--transition-normal);
}

/* Sudoku Specific Styles */
#sudoku-grid {
    display: grid;
    grid-template-columns: repeat(9, 1fr);
    grid-template-rows: repeat(9, 1fr);
    gap: 1px;
    background: var(--text-primary);
    border: 3px solid var(--text-primary);
    margin: var(--spacing-md) auto;
    width: 360px;
    height: 360px;
}

.sudoku-cell {
    background: white;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: var(--font-size-md);
    font-weight: bold;
    cursor: pointer;
    transition: background-color var(--transition-fast);
    user-select: none;
}

.sudoku-cell:hover {
    background: #e8f4fd;
}

.sudoku-cell.selected {
    background: #4CAF50 !important;
    color: white;
}

.sudoku-cell.initial-number {
    background: #f0f0f0;
    color: var(--text-primary);
    cursor: not-allowed;
}

.sudoku-cell.user-number {
    background: #e8f4fd;
    color: #2196F3;
}

.sudoku-cell.error-cell {
    background: #ffebee !important;
    color: #f44336 !important;
    animation: shake 0.5s;
}

.sudoku-cell.border-top { border-top: 3px solid var(--text-primary); }
.sudoku-cell.border-bottom { border-bottom: 3px solid var(--text-primary); }
.sudoku-cell.border-left { border-left: 3px solid var(--text-primary); }
.sudoku-cell.border-right { border-right: 3px solid var(--text-primary); }

#sudoku-numbers {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 8px;
    margin: var(--spacing-md) 0;
    max-width: 350px;
    margin-left: auto;
    margin-right: auto;
}

.number-btn {
    padding: 12px;
    font-size: var(--font-size-md);
    font-weight: bold;
    border: 2px solid #4CAF50;
    background: white;
    color: #4CAF50;
    border-radius: var(--radius-lg);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.number-btn:hover {
    background: #4CAF50;
    color: white;
    transform: translateY(-2px);
}

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

#sudoku-controls, #crossword-controls {
    display: flex;
    justify-content: center;
    gap: var(--spacing-sm);
    margin: var(--spacing-md) 0;
    flex-wrap: wrap;
}

/* Crossword Specific Styles */
.crossword-container {
    display: flex;
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-md);
}

#crossword-grid {
    display: grid;
    gap: 1px;
    background-color: var(--text-primary);
    border: 2px solid var(--text-primary);
    flex-shrink: 0;
}

.crossword-cell {
    position: relative;
    background-color: white;
    display: flex;
    align-items: center;
    justify-content: center;
}

.crossword-cell.blocked-cell {
    background-color: var(--text-primary);
}

.cell-number {
    position: absolute;
    top: 1px;
    left: 2px;
    font-size: var(--spacing-sm);
    font-weight: bold;
    color: var(--text-primary);
    z-index: 1;
}

.cell-input {
    width: 100%;
    height: 100%;
    border: none;
    text-align: center;
    font-size: var(--font-size-md);
    font-weight: bold;
    background: transparent;
    outline: none;
    text-transform: uppercase;
}

.cell-input:focus {
    background-color: #e3f2fd;
    box-shadow: inset 0 0 0 2px #2196f3;
}

#crossword-clues {
    min-width: 300px;
    max-width: 400px;
}

.clues-section {
    margin-bottom: var(--spacing-lg);
}

.clues-section h4 {
    margin: 0 0 var(--spacing-sm) 0;
    color: var(--text-primary);
    border-bottom: 2px solid #4CAF50;
    padding-bottom: var(--spacing-xs);
}

.clue-item {
    margin-bottom: 8px;
    padding: var(--spacing-xs);
    background-color: #f9f9f9;
    border-radius: 3px;
    font-size: var(--font-size-base);
    line-height: 1.4;
}

/* Minesweeper Styles */
#mines-grid {
    display: grid;
    gap: 2px;
    max-width: 400px;
    margin: 0 auto;
    justify-content: center;
}

.mines-cell {
    width: 40px;
    height: 40px;
    border: 2px solid #ccc;
    background-color: #f0f0f0;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    font-weight: bold;
    font-size: var(--font-size-base);
    transition: all var(--transition-fast);
}

.mines-cell:hover {
    background-color: #e0e0e0;
    border-color: #999;
}

.mines-cell.revealed {
    background-color: white;
    border-color: #999;
    cursor: default;
}

.mines-cell.mine {
    background-color: #ff4444;
    color: white;
}

.mines-cell.flagged {
    background-color: #ffeb3b;
}

.mines-cell.mines-1 { color: #1976d2; }
.mines-cell.mines-2 { color: #388e3c; }
.mines-cell.mines-3 { color: #d32f2f; }
.mines-cell.mines-4 { color: #7b1fa2; }
.mines-cell.mines-5 { color: #f57c00; }
.mines-cell.mines-6 { color: #0097a7; }
.mines-cell.mines-7 { color: #5d4037; }
.mines-cell.mines-8 { color: #424242; }

/* Equation Modal */
.equation-modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: var(--overlay);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1001;
}

.equation-content {
    background: white;
    padding: var(--spacing-xl);
    border-radius: var(--radius-xl);
    text-align: center;
    min-width: 300px;
}

.equation-display {
    font-size: var(--font-size-xl);
    font-weight: bold;
    margin: var(--spacing-lg) 0;
    color: var(--text-primary);
}

.equation-content input {
    width: 100%;
    padding: var(--spacing-sm);
    font-size: var(--font-size-lg);
    border: 2px solid var(--border-light);
    border-radius: var(--radius-md);
    margin: var(--spacing-sm) 0;
    text-align: center;
}

.equation-buttons {
    display: flex;
    gap: var(--spacing-sm);
    justify-content: center;
    margin-top: var(--spacing-lg);
}

#submit-equation {
    background-color: var(--primary-blue);
}

#submit-equation:hover {
    background-color: var(--primary-blue-dark);
}

#cancel-equation {
    background-color: var(--danger-red);
}

#cancel-equation:hover {
    background-color: var(--danger-red-dark);
}

/* Leaderboard Styles */
.leaderboard-container {
    max-width: 800px;
    margin: 0 auto;
    padding: var(--spacing-lg);
}

.loading-message, .error-message {
    text-align: center;
    padding: var(--spacing-lg);
    font-size: var(--font-size-md);
    color: var(--text-secondary);
}

.error-message {
    color: #d32f2f;
    background-color: #ffebee;
    border: 1px solid #ffcdd2;
    border-radius: var(--radius-sm);
}

#leaderboard-table {
    width: 100%;
    border-collapse: collapse;
    margin-top: var(--spacing-lg);
    background-color: white;
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: 0 2px 10px var(--shadow-light);
}

#leaderboard-table th {
    background-color: #4CAF50;
    color: white;
    padding: var(--spacing-md) var(--spacing-sm);
    text-align: left;
    font-weight: 600;
    font-size: var(--font-size-base);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

#leaderboard-table td {
    padding: 12px var(--spacing-sm);
    border-bottom: 1px solid var(--border-lighter);
    font-size: var(--font-size-base);
}

#leaderboard-table tbody tr:hover {
    background-color: #f5f5f5;
}

#leaderboard-table tbody tr:nth-child(even) {
    background-color: var(--bg-lighter);
}

.rank-cell {
    font-weight: bold;
    text-align: center;
    width: 80px;
}

.rank-cell.rank-1 { color: #ffd700; }
.rank-cell.rank-2 { color: #c0c0c0; }
.rank-cell.rank-3 { color: #cd7f32; }

.player-cell {
    font-weight: 500;
    color: var(--text-primary);
}

.level-cell, .points-cell {
    text-align: center;
    font-weight: 500;
}

.points-cell {
    color: #4CAF50;
}

/* Profile Modal */
.profile-section {
    margin-bottom: var(--spacing-xl);
    padding: var(--spacing-lg);
    border: 1px solid #e0e0e0;
    border-radius: var(--radius-lg);
    background-color: var(--bg-lighter);
}

.profile-section:last-child {
    margin-bottom: 0;
}

.profile-section h3 {
    margin-bottom: var(--spacing-md);
    color: var(--text-primary);
    font-size: var(--font-size-md);
    border-bottom: 2px solid #4CAF50;
    padding-bottom: var(--spacing-xs);
}

#profile-modal .modal-content {
    max-width: 500px;
    max-height: 80vh;
    overflow-y: auto;
}

#current-password-group.hidden {
    display: none;
}

.profile-section .auth-btn {
    background-color: #4CAF50;
    margin-top: var(--spacing-md);
}

.profile-section .auth-btn:hover {
    background-color: #45a049;
}

/* Footer */
footer {
    text-align: center;
    margin-top: 50px;
    padding: var(--spacing-lg);
    color: var(--text-light);
    background-color: #f8f9fa;
    border-top: 1px solid #e9ecef;
}

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

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

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

/* Feedback Form */
#feedback-form textarea {
    width: 100%;
    padding: 0.5rem;
    border: 1px solid #ced4da;
    border-radius: 0.25rem;
    resize: vertical;
}

#feedback-status {
    margin-top: 1rem;
}

#feedback-status.success {
    color: #28a745;
}

#feedback-status.error {
    color: #dc3545;
}

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

@keyframes shake {
    0%, 100% { transform: translateX(0); }
    25% { transform: translateX(-2px); }
    75% { transform: translateX(2px); }
}

/* Responsive Design */
@media (max-width: 768px) {
    header {
        flex-direction: column;
        text-align: center;
    }
    
    #user-info {
        margin-top: var(--spacing-md);
        width: 100%;
    }
    
    .games-grid {
        grid-template-columns: 1fr;
    }
    
    .leaderboard-container {
        padding: var(--spacing-sm);
    }
    
    #leaderboard-table th,
    #leaderboard-table td {
        padding: 8px var(--spacing-xs);
        font-size: var(--font-size-sm);
    }
    
    #leaderboard-table th {
        font-size: 11px;
    }
    
    #profile-modal .modal-content {
        width: 95%;
        padding: var(--spacing-lg);
    }
    
    .profile-section {
        margin-bottom: var(--spacing-lg);
    }
    
    #sudoku-game, #crossword-game {
        width: 95%;
        max-width: none;
        padding: var(--spacing-md);
        max-height: 90vh;
    }
    
    #sudoku-grid {
        width: 320px;
        height: 320px;
    }
    
    .sudoku-cell {
        font-size: var(--font-size-base);
    }
    
    #sudoku-numbers {
        grid-template-columns: repeat(3, 1fr);
        gap: var(--spacing-xs);
        max-width: 300px;
    }
    
    .number-btn {
        padding: var(--spacing-sm);
        font-size: var(--font-size-base);
    }
    
    #sudoku-status, #crossword-status, #mines-status {
        flex-direction: column;
        gap: var(--spacing-xs);
        text-align: center;
    }
    
    #sudoku-controls, #crossword-controls {
        flex-direction: column;
        align-items: center;
        gap: 8px;
    }
    
    #sudoku-controls button, #crossword-controls button {
        width: 200px;
    }
    
    #sudoku-message, #crossword-message {
        width: 100%;
    }
    
    .crossword-container {
        flex-direction: column;
        align-items: center;
    }
    
    .crossword-cell {
        width: 30px;
        height: 30px;
    }
    
    .cell-input {
        font-size: var(--font-size-base);
    }
    
    #crossword-clues {
        min-width: auto;
        max-width: 100%;
    }
    
    #mines-grid {
        max-width: 300px;
    }
    
    .mines-cell {
        width: 35px;
        height: 35px;
        font-size: var(--font-size-sm);
    }
    
    .equation-content {
        padding: var(--spacing-lg);
        min-width: 250px;
        width: 90%;
    }
    
    .equation-display {
        font-size: var(--spacing-lg);
    }
}