:root {
    /* Updated Root Variables */
    --primary-color: #4a90e2;
    --secondary-color: #2c3e50;
    --accent-color: #2c3e50;
    --card-bg: #ffffff;
    --text-shadow: none;
    --box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    --page-bg: linear-gradient(135deg, #f6f8fc 0%, #e2e8f0 100%);
}

/* Updated Neon Theme with Better Contrast */
[data-theme="neon"] {
    --primary-color: #00ffbb;
    --secondary-color: #1a1b2e;
    --accent-color: #ff2d95;
    --card-bg: #252942;
    --text-shadow: 0 0 5px rgba(0, 255, 187, 0.5);
    --box-shadow: 0 0 10px rgba(0, 255, 187, 0.3);
    --page-bg: linear-gradient(135deg, #0f1118 0%, #1a1b2e 100%);
}

[data-theme="dark"] {
    --primary-color: #2c3e50;
    --secondary-color: #34495e;
    --accent-color: #ecf0f1;
    --card-bg: #1a1a1a;
}

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

body {
    background: var(--page-bg);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    font-family: 'Poppins', sans-serif;
    transition: all 0.3s ease;
}

[data-theme="neon"] body::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: 
        linear-gradient(45deg, 
            rgba(255,0,255,0.1) 0%,
            rgba(0,255,255,0.1) 100%);
    pointer-events: none;
}

.game-container {
    max-width: 1200px;
    padding: 30px;
    background: rgba(255, 255, 255, 0.95);
    border-radius: 20px;
    backdrop-filter: blur(10px);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
}

[data-theme="neon"] .game-container {
    background: rgba(37, 41, 66, 0.95);
    border: 1px solid var(--primary-color);
    box-shadow: 0 0 20px rgba(0, 255, 187, 0.1);
}

.game-header {
    background: rgba(255, 255, 255, 0.1);
    padding: 20px;
    border-radius: 15px;
    margin-bottom: 30px;
}

[data-theme="neon"] .game-header {
    border: 1px solid var(--primary-color);
    box-shadow: var(--box-shadow);
}

.game-grid {
    display: grid;
    gap: 10px;
    margin: 20px 0;
}

/* Grid sizes for different difficulties */
.grid-easy {
    grid-template-columns: repeat(4, 1fr);
}

.grid-medium {
    grid-template-columns: repeat(6, 1fr);
}

.grid-hard {
    grid-template-columns: repeat(8, 1fr);
}

.card {
    aspect-ratio: 1;
    background: white;
    border-radius: 12px;
    cursor: pointer;
    transition: transform 0.6s cubic-bezier(0.4, 0, 0.2, 1);
    transform-style: preserve-3d;
    position: relative;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
}

[data-theme="neon"] .card {
    background: #252942;
    border: 1px solid var(--primary-color);
    box-shadow: 0 0 10px rgba(0, 255, 187, 0.2);
}

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

.card-front, .card-back {
    position: absolute;
    width: 100%;
    height: 100%;
    backface-visibility: hidden;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2.5em;
    border-radius: 12px;
}

.card-front {
    background: var(--primary-color);
    transform: rotateY(180deg);
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 12px;
}

.card-front .emoji {
    font-size: min(2em, calc(100% + 1vw)); /* Responsive sizing */
    line-height: 1;
    font-family: 'Segoe UI Emoji', 'Apple Color Emoji', 'Noto Color Emoji', sans-serif;
    display: block;
    transform: rotateY(0deg);
    user-select: none;
    -webkit-user-select: none;
    padding: 5px;
    text-align: center;
}

/* Ensure emojis are visible in all themes */
[data-theme="neon"] .card-front .emoji {
    color: var(--primary-color);
    text-shadow: 0 0 5px var(--primary-color);
}

[data-theme="dark"] .card-front .emoji {
    color: white;
    text-shadow: none;
}

.card-back {
    background: #f0f0f0;
    color: var(--secondary-color);
}

[data-theme="neon"] .card-back {
    background: #1a1b2e;
    color: var(--primary-color);
    border: 1px solid var(--primary-color);
}

/* Animation Classes */
.card.matched {
    animation: matchedAnimation 0.5s ease-in-out, neonMatchGlow 1s ease-in-out;
}

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

@keyframes neonMatchGlow {
    0% { box-shadow: 0 0 10px var(--accent-color); }
    50% { box-shadow: 0 0 30px var(--accent-color); }
    100% { box-shadow: 0 0 10px var(--accent-color); }
}

/* Enhanced Theme Switcher Buttons */
.theme-switcher {
    display: flex;
    gap: 15px;
    margin-bottom: 25px;
    justify-content: center;
}

.theme-switcher button {
    padding: 12px 25px;
    border: none;
    border-radius: 12px;
    font-size: 0.95rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    background: var(--primary-color);
    color: white;
    letter-spacing: 0.5px;
}

[data-theme="neon"] .theme-switcher button {
    background: #252942;
    border: 1px solid var(--primary-color);
    color: var(--primary-color);
    box-shadow: 0 0 10px rgba(0, 255, 187, 0.2);
}

.theme-switcher button:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(74, 144, 226, 0.3);
}

[data-theme="neon"] .theme-switcher button:hover {
    background: var(--primary-color);
    color: #252942;
}

/* Enhanced Score Display */
.score-container {
    background: rgba(255, 255, 255, 0.1);
    padding: 15px;
    border-radius: 12px;
    display: flex;
    justify-content: space-around;
    margin-bottom: 20px;
}

[data-theme="neon"] .score-container {
    background: rgba(37, 41, 66, 0.8);
    border: 1px solid var(--primary-color);
}

.score-container span {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--secondary-color);
}

[data-theme="neon"] .score-container span {
    color: var(--primary-color);
}

/* Enhanced Controls */
.controls {
    display: flex;
    gap: 15px;
    justify-content: center;
}

.controls button, .difficulty-select button {
    padding: 12px 24px;
    border: none;
    border-radius: 12px;
    background: var(--primary-color);
    color: white;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    letter-spacing: 0.5px;
}

[data-theme="neon"] .controls button, 
[data-theme="neon"] .difficulty-select button {
    background: #252942;
    border: 1px solid var(--primary-color);
    color: var(--primary-color);
}

.controls button:hover, 
.difficulty-select button:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(74, 144, 226, 0.3);
}

[data-theme="neon"] .controls button:hover,
[data-theme="neon"] .difficulty-select button:hover {
    background: var(--primary-color);
    color: #252942;
}

/* Enhanced Leaderboard */
.leaderboard {
    background: rgba(255, 255, 255, 0.9);
    border-radius: 12px;
    padding: 20px;
    margin-top: 30px;
}

[data-theme="neon"] .leaderboard {
    background: rgba(37, 41, 66, 0.8);
    border: 1px solid var(--primary-color);
}

.leaderboard h2 {
    color: var(--accent-color);
    text-align: center;
    margin-bottom: 15px;
}

[data-theme="neon"] .leaderboard h2 {
    color: var(--primary-color);
    text-shadow: var(--text-shadow);
}

.leaderboard-entry {
    padding: 10px;
    margin: 5px 0;
    border-radius: 8px;
    background: rgba(255, 255, 255, 0.5);
}

[data-theme="neon"] .leaderboard-entry {
    background: rgba(37, 41, 66, 0.5);
    color: var(--primary-color);
    border: 1px solid var(--primary-color);
}

/* Enhanced Modal */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    justify-content: center;
    align-items: center;
}

.modal-content {
    background: var(--secondary-color);
    padding: 30px;
    border-radius: 20px;
    text-align: center;
    box-shadow: var(--box-shadow);
}

[data-theme="neon"] .modal-content {
    background: var(--card-bg);
    border: 2px solid var(--primary-color);
    color: var(--primary-color);
    text-shadow: var(--text-shadow);
}

/* Enhanced Animations */
@keyframes neonPulse {
    0% { box-shadow: 0 0 10px var(--primary-color); }
    50% { box-shadow: 0 0 20px var(--primary-color), 0 0 30px var(--primary-color); }
    100% { box-shadow: 0 0 10px var(--primary-color); }
}

/* Updated Emoji Display */
.card-front {
    font-family: 'Segoe UI Emoji', 'Apple Color Emoji', sans-serif;
    font-size: 2.8em;
}

/* Responsive Enhancements */
@media (max-width: 768px) {
    .game-container {
        padding: 15px;
        margin: 10px;
    }

    .theme-switcher {
        flex-wrap: wrap;
    }

    .controls {
        flex-direction: column;
    }

    .score-container {
        flex-direction: column;
        align-items: center;
        gap: 10px;
    }
}

/* Adjust card sizes for different difficulties */
.grid-easy .card {
    min-height: 80px;
    max-height: 120px;
}

.grid-medium .card {
    min-height: 70px;
    max-height: 100px;
}

.grid-hard .card {
    min-height: 60px;
    max-height: 80px;
}