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

:root {
    /* Light theme variables */
    --bg-primary: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --bg-secondary: rgba(255, 255, 255, 0.95);
    --text-primary: #333;
    --text-secondary: #666;
    --text-light: #555;
    --header-bg: rgba(255, 255, 255, 0.95);
    --menu-bg: rgba(255, 255, 255, 0.95);
    --button-primary: linear-gradient(45deg, #4CAF50, #45a049);
    --button-secondary: linear-gradient(45deg, #2196F3, #1976D2);
    --button-accent: linear-gradient(45deg, #9C27B0, #7B1FA2);
    --button-warning: linear-gradient(45deg, #FF9800, #F57C00);
    --shadow: rgba(0, 0, 0, 0.2);
    --border-color: #f0f0f0;
    --game-bg: linear-gradient(180deg, #87CEEB 0%, #98FB98 100%);
}

[data-theme="dark"] {
    /* Dark theme variables */
    --bg-primary: linear-gradient(135deg, #1a1a2e 0%, #16213e 100%);
    --bg-secondary: rgba(30, 30, 30, 0.95);
    --text-primary: #ffffff;
    --text-secondary: #cccccc;
    --text-light: #aaaaaa;
    --header-bg: rgba(30, 30, 30, 0.95);
    --menu-bg: rgba(30, 30, 30, 0.95);
    --button-primary: linear-gradient(45deg, #2d5a2d, #1e3a1e);
    --button-secondary: linear-gradient(45deg, #1e3a5f, #0d2440);
    --button-accent: linear-gradient(45deg, #4a1a4a, #2d0f2d);
    --button-warning: linear-gradient(45deg, #5d3a00, #3d2500);
    --shadow: rgba(0, 0, 0, 0.5);
    --border-color: #444;
    --game-bg: linear-gradient(180deg, #2c5f7c 0%, #3a5f3a 100%);
}

body {
    font-family: 'Arial', sans-serif;
    background: var(--bg-primary);
    height: 100vh;
    overflow: hidden;
    display: flex;
    flex-direction: column;
    transition: background 0.3s ease;
}

/* Header Styles */
.game-header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: 60px;
    background: var(--header-bg);
    backdrop-filter: blur(10px);
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 20px;
    box-shadow: 0 2px 10px var(--shadow);
    z-index: 1000;
    transition: background 0.3s ease;
}

.version-info {
    font-size: 1rem;
    color: var(--text-secondary);
    font-weight: 500;
    transition: color 0.3s ease;
}

.header-buttons {
    display: flex;
    gap: 10px;
    align-items: center;
}

.coin-display {
    display: flex;
    align-items: center;
    gap: 5px;
    background: var(--bg-secondary);
    padding: 8px 12px;
    border-radius: 20px;
    box-shadow: 0 2px 8px var(--shadow);
    font-weight: bold;
    color: var(--text-primary);
}

.coin-icon {
    font-size: 1.2rem;
}

.theme-toggle-btn {
    padding: 8px;
    font-size: 1.2rem;
    background: var(--button-accent);
    color: white;
    border: none;
    border-radius: 50%;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 2px 8px var(--shadow);
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.theme-toggle-btn:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 12px var(--shadow);
}

.sound-toggle-btn {
    padding: 8px;
    font-size: 1.2rem;
    background: var(--button-secondary);
    color: white;
    border: none;
    border-radius: 50%;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 2px 8px var(--shadow);
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.sound-toggle-btn:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 12px var(--shadow);
}

.sound-toggle-btn.muted {
    background: var(--button-warning);
}

.inventory-btn {
    padding: 8px;
    font-size: 1.2rem;
    background: var(--button-primary);
    color: white;
    border: none;
    border-radius: 50%;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 2px 8px var(--shadow);
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.inventory-btn:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 12px var(--shadow);
}

.changelog-btn {
    padding: 8px 16px;
    font-size: 0.9rem;
    background: var(--button-accent);
    color: white;
    border: none;
    border-radius: 20px;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 2px 8px var(--shadow);
}

.changelog-btn:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 12px var(--shadow);
}

.screen {
    position: absolute;
    width: 100%;
    height: 100%;
    display: none;
    justify-content: center;
    align-items: center;
    flex-direction: column;
    margin-top: 60px; /* Account for header height */
}

.screen.active {
    display: flex;
}

/* Main Menu Styles */
.menu-container {
    text-align: center;
    background: var(--menu-bg);
    padding: 40px;
    border-radius: 20px;
    box-shadow: 0 10px 30px var(--shadow);
    backdrop-filter: blur(10px);
}

.game-title {
    font-size: 3.5rem;
    color: var(--text-primary);
    margin-bottom: 30px;
    text-shadow: 2px 2px 4px var(--shadow);
    font-weight: bold;
}

.high-score-display {
    font-size: 1.2rem;
    color: var(--text-secondary);
    margin-bottom: 30px;
    padding: 10px 20px;
    background: var(--border-color);
    border-radius: 10px;
    display: inline-block;
}

.menu-buttons {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.menu-btn {
    padding: 15px 40px;
    font-size: 1.3rem;
    background: var(--button-primary);
    color: white;
    border: none;
    border-radius: 25px;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px var(--shadow);
}

.menu-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px var(--shadow);
    background: var(--button-primary);
}

/* Levels Screen Styles */
.levels-container {
    text-align: center;
    background: var(--menu-bg);
    padding: 40px;
    border-radius: 20px;
    box-shadow: 0 10px 30px var(--shadow);
    backdrop-filter: blur(10px);
}

.levels-container h2 {
    font-size: 2.5rem;
    color: var(--text-primary);
    margin-bottom: 30px;
}

.level-buttons {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 20px;
    margin-bottom: 30px;
}

.level-btn {
    padding: 20px 30px;
    font-size: 1.2rem;
    background: var(--button-secondary);
    color: white;
    border: none;
    border-radius: 15px;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px var(--shadow);
}

.level-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px var(--shadow);
    background: var(--button-secondary);
}

.back-btn {
    padding: 12px 25px;
    font-size: 1rem;
    background: var(--button-warning);
    color: white;
    border: none;
    border-radius: 20px;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px var(--shadow);
}

.back-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px var(--shadow);
    background: var(--button-warning);
}

/* Changelog Screen Styles */
.changelog-container {
    text-align: center;
    background: var(--menu-bg);
    padding: 40px;
    border-radius: 20px;
    box-shadow: 0 10px 30px var(--shadow);
    backdrop-filter: blur(10px);
    max-width: 800px;
    max-height: 80vh;
    overflow-y: auto;
}

.changelog-container h2 {
    font-size: 2.5rem;
    color: var(--text-primary);
    margin-bottom: 30px;
}

.changelog-content {
    text-align: left;
    margin-bottom: 30px;
}

.version-entry {
    margin-bottom: 30px;
    padding: 20px;
    background: var(--border-color);
    border-radius: 15px;
    border-left: 5px solid #9C27B0;
}

.version-entry h3 {
    font-size: 1.5rem;
    color: #9C27B0;
    margin-bottom: 15px;
    font-weight: bold;
}

.version-entry ul {
    list-style-type: none;
    padding-left: 0;
}

.version-entry li {
    padding: 8px 0;
    color: var(--text-light);
    position: relative;
    padding-left: 25px;
}

.version-entry li:before {
    content: "•";
    color: #9C27B0;
    font-weight: bold;
    font-size: 1.2rem;
    position: absolute;
    left: 0;
    top: 6px;
}

/* Game Screen Styles */
#gameScreen {
    background: var(--game-bg);
    position: relative;
}

#gameCanvas {
    border: 2px solid var(--text-primary);
    background: var(--game-bg);
    box-shadow: 0 0 20px var(--shadow);
}

.game-ui {
    position: absolute;
    top: 20px;
    left: 20px;
    z-index: 10;
}

.score-display {
    display: flex;
    flex-direction: column;
    gap: 10px;
    background: var(--bg-secondary);
    padding: 15px;
    border-radius: 10px;
    box-shadow: 0 4px 15px var(--shadow);
    font-size: 1.1rem;
    font-weight: bold;
    color: var(--text-primary);
}

.level-up-popup {
    position: absolute;
    top: 25%;
    left: 50%;
    transform: translate(-50%, 0);
    background: linear-gradient(45deg, #FFD700, #FFA500);
    color: white;
    padding: 20px 40px;
    border-radius: 15px;
    font-size: 2rem;
    font-weight: bold;
    box-shadow: 0 8px 25px var(--shadow);
    animation: popupAnimation 0.5s ease-out;
    z-index: 100;
    border: 5px solid #FF6B35;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.5);
}

@keyframes popupAnimation {
    0% {
        transform: translate(-50%, -50%) scale(0);
        opacity: 0;
    }
    50% {
        transform: translate(-50%, -50%) scale(1.2);
        opacity: 1;
    }
    100% {
        transform: translate(-50%, -50%) scale(1);
        opacity: 1;
    }
}

.game-over {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.8);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 30;
}

.game-over-content {
    background: var(--bg-secondary);
    padding: 40px;
    border-radius: 20px;
    text-align: center;
    box-shadow: 0 10px 30px var(--shadow);
}

.game-over-content h2 {
    font-size: 2.5rem;
    color: #e74c3c;
    margin-bottom: 20px;
}

.game-over-content p {
    font-size: 1.2rem;
    color: var(--text-primary);
    margin-bottom: 10px;
}

.hidden {
    display: none !important;
}

.level-display {
    position: absolute;
    top: 20px;
    right: 20px;
    background: var(--bg-secondary);
    color: var(--text-primary);
    padding: 10px 20px;
    border-radius: 10px;
    font-size: 1.2rem;
    font-weight: bold;
    z-index: 120;
    letter-spacing: 2px;
    box-shadow: 0 2px 10px var(--shadow);
}

.game-complete-popup {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    background: var(--bg-secondary);
    color: var(--text-primary);
    padding: 40px;
    border-radius: 20px;
    text-align: center;
    z-index: 150;
    box-shadow: 0 10px 30px var(--shadow);
}

.game-complete-popup h2 {
    font-size: 2rem;
    color: var(--text-primary);
    margin-bottom: 20px;
}

.game-complete-popup p {
    font-size: 1.1rem;
    color: var(--text-secondary);
    line-height: 1.5;
}

/* Coin Popup Animation */
@keyframes coinPopupAnimation {
    0% {
        transform: translate(-50%, -50%) scale(0);
        opacity: 0;
    }
    50% {
        transform: translate(-50%, -50%) scale(1.2);
        opacity: 1;
    }
    100% {
        transform: translate(-50%, -50%) scale(1);
        opacity: 0;
    }
}

/* Message Popup Animation */
@keyframes messagePopupAnimation {
    0% {
        transform: translate(-50%, -50%) scale(0);
        opacity: 0;
    }
    20% {
        transform: translate(-50%, -50%) scale(1.1);
        opacity: 1;
    }
    80% {
        transform: translate(-50%, -50%) scale(1);
        opacity: 1;
    }
    100% {
        transform: translate(-50%, -50%) scale(0.9);
        opacity: 0;
    }
}

/* Inventory Screen Styles */
.inventory-container {
    text-align: center;
    background: var(--menu-bg);
    padding: 40px;
    border-radius: 20px;
    box-shadow: 0 10px 30px var(--shadow);
    backdrop-filter: blur(10px);
    max-width: 1000px;
    max-height: 80vh;
    overflow-y: auto;
}

.inventory-container h2 {
    font-size: 2.5rem;
    color: var(--text-primary);
    margin-bottom: 30px;
}

.inventory-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 30px;
    margin-bottom: 30px;
}

.shop-section, .inventory-section {
    text-align: left;
}

.shop-section h3, .inventory-section h3 {
    font-size: 1.8rem;
    color: var(--text-primary);
    margin-bottom: 20px;
    text-align: center;
}

.shop-items, .owned-items {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.shop-item, .owned-item {
    display: flex;
    align-items: center;
    gap: 15px;
    background: var(--bg-secondary);
    padding: 15px;
    border-radius: 15px;
    box-shadow: 0 4px 15px var(--shadow);
    transition: all 0.3s ease;
}

.shop-item:hover, .owned-item:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px var(--shadow);
}

.item-icon {
    font-size: 2rem;
    min-width: 50px;
    text-align: center;
    transform: scaleX(-1);
}

.item-info {
    flex: 1;
}

.item-info h4 {
    font-size: 1.2rem;
    color: var(--text-primary);
    margin-bottom: 5px;
}

.item-info p {
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin-bottom: 5px;
}

.price {
    font-size: 1rem;
    color: #FFD700;
    font-weight: bold;
}

.buy-btn, .equip-btn {
    padding: 8px 16px;
    font-size: 0.9rem;
    background: var(--button-primary);
    color: white;
    border: none;
    border-radius: 15px;
    cursor: pointer;
    transition: all 0.3s ease;
    min-width: 80px;
}

.buy-btn:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 12px var(--shadow);
}

.equip-btn {
    background: var(--button-secondary);
}

.equip-btn.equipped {
    background: var(--button-accent);
}

.shop-item.owned {
    opacity: 0.6;
}

.shop-item.owned .buy-btn {
    background: var(--button-secondary);
    cursor: not-allowed;
}

.shop-item.owned .buy-btn:hover {
    transform: none;
    box-shadow: 0 2px 8px var(--shadow);
}

/* Responsive Design */
@media (max-width: 768px) {
    .menu-container, .levels-container {
        padding: 20px;
        margin: 20px;
    }
    
    .game-title {
        font-size: 2.5rem;
    }
    
    .level-buttons {
        grid-template-columns: 1fr;
    }
    
    .menu-btn, .level-btn {
        padding: 12px 25px;
        font-size: 1.1rem;
    }
}