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

body {
    font-family: 'Roboto', sans-serif;
    background: #000000;
    min-height: 100vh;
    overflow-x: hidden;
    position: relative;
}

/* Animated Background */
.background-animation {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: 
        radial-gradient(circle at 20% 80%, rgba(0, 255, 204, 0.1) 0%, transparent 50%),
        radial-gradient(circle at 80% 20%, rgba(0, 255, 204, 0.1) 0%, transparent 50%),
        radial-gradient(circle at 40% 40%, rgba(0, 255, 204, 0.05) 0%, transparent 50%),
        linear-gradient(90deg, transparent 49%, rgba(0, 255, 204, 0.03) 50%, transparent 51%),
        linear-gradient(0deg, transparent 49%, rgba(0, 255, 204, 0.03) 50%, transparent 51%),
        #000000;
    background-size: 100% 100%, 100% 100%, 100% 100%, 50px 50px, 50px 50px, 100% 100%;
    animation: gridPulse 4s ease-in-out infinite;
    z-index: -1;
}

.background-animation::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-image: 
        radial-gradient(circle at 10% 20%, rgba(0, 255, 204, 0.8) 0px, transparent 2px),
        radial-gradient(circle at 90% 80%, rgba(0, 255, 204, 0.6) 0px, transparent 1px),
        radial-gradient(circle at 30% 70%, rgba(0, 255, 204, 0.4) 0px, transparent 1px),
        radial-gradient(circle at 70% 30%, rgba(0, 255, 204, 0.5) 0px, transparent 1px),
        radial-gradient(circle at 50% 10%, rgba(0, 255, 204, 0.3) 0px, transparent 1px),
        radial-gradient(circle at 20% 50%, rgba(0, 255, 204, 0.4) 0px, transparent 1px),
        radial-gradient(circle at 80% 60%, rgba(0, 255, 204, 0.3) 0px, transparent 1px);
    animation: particleFloat 8s ease-in-out infinite;
}

@keyframes gridPulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.8; }
}

@keyframes particleFloat {
    0%, 100% { transform: translateY(0px) translateX(0px); }
    25% { transform: translateY(-10px) translateX(5px); }
    50% { transform: translateY(-5px) translateX(-5px); }
    75% { transform: translateY(-15px) translateX(3px); }
}

/* Header Styles */
.header {
    padding: 20px;
    text-align: center;
    background: rgba(0, 255, 204, 0.05);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid rgba(0, 255, 204, 0.2);
    box-shadow: 0 1px 20px rgba(0, 255, 204, 0.1);
}

.logo-container {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 20px;
    flex-wrap: wrap;
}

.logo {
    width: 80px;
    height: 80px;
    border-radius: 50%;
    box-shadow: 
        0 0 20px rgba(0, 255, 204, 0.4),
        0 0 40px rgba(0, 255, 204, 0.2),
        0 0 60px rgba(0, 255, 204, 0.1);
    animation: logoFloat 3s ease-in-out infinite;
    transition: transform 0.3s ease;
    position: relative;
}

.logo::before {
    content: '';
    position: absolute;
    top: -15px;
    left: -15px;
    right: -15px;
    bottom: -15px;
    border: 2px solid rgba(0, 255, 204, 0.3);
    border-radius: 50%;
    animation: logoRing1 4s ease-in-out infinite;
}

.logo::after {
    content: '';
    position: absolute;
    top: -25px;
    left: -25px;
    right: -25px;
    bottom: -25px;
    border: 1px solid rgba(0, 255, 204, 0.2);
    border-radius: 50%;
    animation: logoRing2 6s ease-in-out infinite reverse;
}

.logo:hover {
    transform: scale(1.1) rotateY(180deg);
    box-shadow: 
        0 0 30px rgba(0, 255, 204, 0.6),
        0 0 50px rgba(0, 255, 204, 0.4),
        0 0 70px rgba(0, 255, 204, 0.2);
}

@keyframes logoRing1 {
    0%, 100% { transform: scale(1) rotate(0deg); opacity: 0.3; }
    50% { transform: scale(1.1) rotate(180deg); opacity: 0.6; }
}

@keyframes logoRing2 {
    0%, 100% { transform: scale(1) rotate(0deg); opacity: 0.2; }
    50% { transform: scale(1.15) rotate(-180deg); opacity: 0.4; }
}

@keyframes logoFloat {
    0%, 100% { transform: translateY(0px); }
    50% { transform: translateY(-10px); }
}

.title-container {
    text-align: center;
}

.main-title {
    font-family: 'Orbitron', monospace;
    font-size: 2.5rem;
    font-weight: 900;
    color: #00ffcc;
    text-shadow: 
        0 0 10px rgba(0, 255, 204, 0.8),
        0 0 20px rgba(0, 255, 204, 0.6),
        0 0 30px rgba(0, 255, 204, 0.4),
        0 0 40px rgba(0, 255, 204, 0.2);
    margin-bottom: 10px;
    animation: titleGlow 2s ease-in-out infinite alternate;
}

@keyframes titleGlow {
    from { 
        text-shadow: 
            0 0 10px rgba(0, 255, 204, 0.8),
            0 0 20px rgba(0, 255, 204, 0.6),
            0 0 30px rgba(0, 255, 204, 0.4),
            0 0 40px rgba(0, 255, 204, 0.2);
    }
    to { 
        text-shadow: 
            0 0 15px rgba(0, 255, 204, 1),
            0 0 25px rgba(0, 255, 204, 0.8),
            0 0 35px rgba(0, 255, 204, 0.6),
            0 0 45px rgba(0, 255, 204, 0.4);
    }
}

.subtitle {
    font-size: 1.1rem;
    color: rgba(0, 255, 204, 0.8);
    font-weight: 300;
    font-style: italic;
    text-shadow: 0 0 10px rgba(0, 255, 204, 0.3);
}

/* Main Container */
.main-container {
    padding: 40px 20px;
    max-width: 1200px;
    margin: 0 auto;
}

/* Mode Selection */
.mode-selection, .difficulty-selection, .username-input {
    text-align: center;
    animation: fadeInUp 0.8s ease;
}

.mode-selection h2, .difficulty-selection h2 {
    font-family: 'Orbitron', monospace;
    font-size: 2.2rem;
    color: #00ffcc;
    margin-bottom: 40px;
    text-shadow: 
        0 0 10px rgba(0, 255, 204, 0.8),
        0 0 20px rgba(0, 255, 204, 0.6),
        0 0 30px rgba(0, 255, 204, 0.4);
}

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

.mode-btn, .difficulty-btn {
    background: rgba(0, 255, 204, 0.1);
    backdrop-filter: blur(10px);
    border: 2px solid rgba(0, 255, 204, 0.3);
    border-radius: 20px;
    padding: 30px 40px;
    color: #00ffcc;
    cursor: pointer;
    transition: all 0.3s ease;
    transform-style: preserve-3d;
    perspective: 1000px;
    min-width: 200px;
    box-shadow: 
        0 0 20px rgba(0, 255, 204, 0.1),
        inset 0 0 20px rgba(0, 255, 204, 0.05);
}

.mode-btn:hover, .difficulty-btn:hover {
    transform: translateY(-10px) rotateX(10deg);
    background: rgba(0, 255, 204, 0.2);
    border-color: rgba(0, 255, 204, 0.6);
    box-shadow: 
        0 20px 40px rgba(0, 0, 0, 0.5),
        0 0 30px rgba(0, 255, 204, 0.4),
        inset 0 0 30px rgba(0, 255, 204, 0.1);
    text-shadow: 0 0 10px rgba(0, 255, 204, 0.8);
}

.mode-icon, .difficulty-icon {
    display: block;
    font-size: 3rem;
    margin-bottom: 15px;
    animation: bounce 2s infinite;
}

@keyframes bounce {
    0%, 20%, 50%, 80%, 100% { transform: translateY(0); }
    40% { transform: translateY(-10px); }
    60% { transform: translateY(-5px); }
}

.mode-text, .difficulty-text {
    display: block;
    font-size: 1.3rem;
    font-weight: 700;
    margin-bottom: 8px;
}

.mode-desc, .difficulty-desc {
    display: block;
    font-size: 0.9rem;
    opacity: 0.8;
}

/* Game Container */
.game-container {
    animation: fadeInUp 0.8s ease;
}

.game-info {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 30px;
    flex-wrap: wrap;
    gap: 20px;
}

.current-player {
    font-size: 1.5rem;
    font-weight: 700;
    color: #00ffcc;
    text-shadow: 
        0 0 10px rgba(0, 255, 204, 0.8),
        0 0 20px rgba(0, 255, 204, 0.6);
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0% { opacity: 1; }
    50% { opacity: 0.7; }
    100% { opacity: 1; }
}

.game-stats {
    display: flex;
    gap: 20px;
    font-size: 1rem;
    color: rgba(0, 255, 204, 0.8);
    text-shadow: 0 0 5px rgba(0, 255, 204, 0.3);
}

/* 3D Game Board */
.board-container {
    position: relative;
    display: flex;
    justify-content: center;
    margin-bottom: 40px;
    perspective: 1000px;
}

.game-board {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    grid-template-rows: repeat(3, 1fr);
    gap: 10px;
    background: rgba(0, 255, 204, 0.05);
    padding: 20px;
    border-radius: 20px;
    backdrop-filter: blur(10px);
    border: 2px solid rgba(0, 255, 204, 0.3);
    transform-style: preserve-3d;
    animation: boardEntrance 1s ease;
    box-shadow: 
        0 20px 60px rgba(0, 0, 0, 0.5),
        0 0 40px rgba(0, 255, 204, 0.2),
        inset 0 0 40px rgba(0, 255, 204, 0.05);
}

@keyframes boardEntrance {
    from {
        transform: rotateX(-90deg) translateY(100px);
        opacity: 0;
    }
    to {
        transform: rotateX(0deg) translateY(0px);
        opacity: 1;
    }
}

.cell {
    width: 100px;
    height: 100px;
    background: rgba(0, 255, 204, 0.1);
    border: 2px solid rgba(0, 255, 204, 0.3);
    border-radius: 15px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 3rem;
    font-weight: 900;
    cursor: pointer;
    transition: all 0.3s ease;
    transform-style: preserve-3d;
    position: relative;
    overflow: hidden;
    box-shadow: 
        0 0 15px rgba(0, 255, 204, 0.1),
        inset 0 0 15px rgba(0, 255, 204, 0.05);
}

.cell::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(45deg, transparent, rgba(255, 255, 255, 0.1), transparent);
    transform: translateX(-100%);
    transition: transform 0.6s ease;
}

.cell:hover::before {
    transform: translateX(100%);
}

.cell:hover {
    transform: translateZ(20px) rotateX(10deg);
    background: rgba(0, 255, 204, 0.2);
    border-color: rgba(0, 255, 204, 0.6);
    box-shadow: 
        0 15px 30px rgba(0, 0, 0, 0.6),
        0 0 25px rgba(0, 255, 204, 0.4),
        inset 0 0 25px rgba(0, 255, 204, 0.1);
}

.cell.x {
    color: #ff6b6b;
    text-shadow: 0 5px 15px rgba(255, 107, 107, 0.5);
    animation: cellPop 0.5s ease;
}

.cell.o {
    color: #4ecdc4;
    text-shadow: 0 5px 15px rgba(78, 205, 196, 0.5);
    animation: cellPop 0.5s ease;
}

@keyframes cellPop {
    0% {
        transform: scale(0) rotateZ(180deg);
        opacity: 0;
    }
    50% {
        transform: scale(1.2) rotateZ(90deg);
    }
    100% {
        transform: scale(1) rotateZ(0deg);
        opacity: 1;
    }
}

.cell.winning {
    animation: winningCell 1s ease infinite;
}

@keyframes winningCell {
    0%, 100% {
        background: rgba(255, 255, 255, 0.2);
        transform: scale(1);
    }
    50% {
        background: rgba(255, 215, 0, 0.4);
        transform: scale(1.05);
        box-shadow: 0 0 30px rgba(255, 215, 0, 0.6);
    }
}

/* Winning Line */
.winning-line {
    position: absolute;
    background: linear-gradient(90deg, transparent, #ffd700, transparent);
    height: 6px;
    border-radius: 3px;
    opacity: 0;
    transform-origin: center;
    box-shadow: 0 0 20px #ffd700;
}

.winning-line.show {
    animation: drawLine 0.8s ease forwards;
}

@keyframes drawLine {
    from {
        opacity: 0;
        transform: scaleX(0);
    }
    to {
        opacity: 1;
        transform: scaleX(1);
    }
}

/* Game Controls */
.game-controls {
    display: flex;
    justify-content: center;
    gap: 20px;
    flex-wrap: wrap;
}

.control-btn, .back-btn {
    background: rgba(0, 255, 204, 0.1);
    backdrop-filter: blur(10px);
    border: 2px solid rgba(0, 255, 204, 0.3);
    border-radius: 15px;
    padding: 15px 25px;
    color: #00ffcc;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    transform-style: preserve-3d;
    box-shadow: 
        0 0 15px rgba(0, 255, 204, 0.1),
        inset 0 0 15px rgba(0, 255, 204, 0.05);
}

.control-btn:hover, .back-btn:hover {
    transform: translateY(-5px);
    background: rgba(0, 255, 204, 0.2);
    border-color: rgba(0, 255, 204, 0.6);
    box-shadow: 
        0 10px 25px rgba(0, 0, 0, 0.5),
        0 0 20px rgba(0, 255, 204, 0.4),
        inset 0 0 20px rgba(0, 255, 204, 0.1);
    text-shadow: 0 0 10px rgba(0, 255, 204, 0.8);
}

/* Leaderboard */
.leaderboard {
    background: rgba(0, 255, 204, 0.05);
    backdrop-filter: blur(10px);
    border: 2px solid rgba(0, 255, 204, 0.3);
    border-radius: 20px;
    padding: 30px;
    animation: fadeInUp 0.8s ease;
    box-shadow: 
        0 0 30px rgba(0, 255, 204, 0.1),
        inset 0 0 30px rgba(0, 255, 204, 0.05);
}

.leaderboard h2 {
    font-family: 'Orbitron', monospace;
    font-size: 2rem;
    color: #00ffcc;
    text-align: center;
    margin-bottom: 30px;
    text-shadow: 
        0 0 10px rgba(0, 255, 204, 0.8),
        0 0 20px rgba(0, 255, 204, 0.6),
        0 0 30px rgba(0, 255, 204, 0.4);
}

.leaderboard-tabs {
    display: flex;
    justify-content: center;
    gap: 10px;
    margin-bottom: 30px;
}

.tab-btn {
    background: rgba(0, 255, 204, 0.1);
    border: 2px solid rgba(0, 255, 204, 0.3);
    border-radius: 10px;
    padding: 10px 20px;
    color: #00ffcc;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 0 10px rgba(0, 255, 204, 0.1);
}

.tab-btn.active, .tab-btn:hover {
    background: rgba(0, 255, 204, 0.2);
    border-color: rgba(0, 255, 204, 0.6);
    box-shadow: 0 0 15px rgba(0, 255, 204, 0.3);
    text-shadow: 0 0 10px rgba(0, 255, 204, 0.8);
}

.stats-section {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
}

.stat-item {
    background: rgba(0, 255, 204, 0.1);
    border: 1px solid rgba(0, 255, 204, 0.2);
    border-radius: 10px;
    padding: 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    color: #00ffcc;
    transition: transform 0.3s ease;
    box-shadow: 0 0 10px rgba(0, 255, 204, 0.1);
}

.stat-item:hover {
    transform: translateY(-5px);
    background: rgba(0, 255, 204, 0.15);
    border-color: rgba(0, 255, 204, 0.4);
    box-shadow: 0 5px 20px rgba(0, 255, 204, 0.2);
}

.stat-label {
    font-weight: 600;
}

.difficulty-stats {
    grid-column: 1 / -1;
    margin-top: 20px;
}

.difficulty-stats h3 {
    color: #00ffcc;
    margin-bottom: 15px;
    text-align: center;
    text-shadow: 0 0 10px rgba(0, 255, 204, 0.6);
}

.difficulty-breakdown {
    display: flex;
    justify-content: space-around;
    flex-wrap: wrap;
    gap: 15px;
}

.diff-stat {
    background: rgba(0, 255, 204, 0.1);
    border: 1px solid rgba(0, 255, 204, 0.2);
    border-radius: 8px;
    padding: 10px 15px;
    color: #00ffcc;
    font-size: 0.9rem;
    box-shadow: 0 0 10px rgba(0, 255, 204, 0.1);
}

/* Player Leaderboard Styles */
.player-leaderboard {
    grid-column: 1 / -1;
    margin-top: 30px;
}

.player-leaderboard h3 {
    color: #00ffcc;
    text-align: center;
    margin-bottom: 20px;
    text-shadow: 0 0 10px rgba(0, 255, 204, 0.6);
    font-size: 1.3rem;
}

.player-stats-list {
    display: flex;
    flex-direction: column;
    gap: 10px;
    max-height: 300px;
    overflow-y: auto;
}

.player-stat-item {
    background: rgba(0, 255, 204, 0.1);
    border: 1px solid rgba(0, 255, 204, 0.2);
    border-radius: 10px;
    padding: 15px 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    color: #00ffcc;
    transition: all 0.3s ease;
    box-shadow: 0 0 10px rgba(0, 255, 204, 0.1);
}

.player-stat-item:hover {
    background: rgba(0, 255, 204, 0.15);
    border-color: rgba(0, 255, 204, 0.4);
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(0, 255, 204, 0.2);
}

.player-name {
    font-weight: 600;
    font-size: 1.1rem;
    text-shadow: 0 0 5px rgba(0, 255, 204, 0.6);
}

.player-record {
    font-size: 0.9rem;
    opacity: 0.9;
}

.no-stats {
    text-align: center;
    color: rgba(0, 255, 204, 0.6);
    font-style: italic;
    padding: 20px;
}

/* Modal */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.8);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    backdrop-filter: blur(5px);
}

.modal-content {
    background: rgba(0, 255, 204, 0.1);
    backdrop-filter: blur(20px);
    border: 2px solid rgba(0, 255, 204, 0.3);
    border-radius: 25px;
    padding: 40px;
    text-align: center;
    max-width: 400px;
    width: 90%;
    animation: modalPop 0.5s ease;
    box-shadow: 
        0 0 40px rgba(0, 255, 204, 0.2),
        inset 0 0 40px rgba(0, 255, 204, 0.05);
}

@keyframes modalPop {
    from {
        transform: scale(0.5) rotateY(180deg);
        opacity: 0;
    }
    to {
        transform: scale(1) rotateY(0deg);
        opacity: 1;
    }
}

.result-animation {
    margin-bottom: 20px;
}

.result-icon {
    font-size: 4rem;
    animation: resultSpin 1s ease;
}

@keyframes resultSpin {
    from { transform: rotateY(0deg) scale(0); }
    to { transform: rotateY(360deg) scale(1); }
}

.modal-content h2 {
    font-family: 'Orbitron', monospace;
    font-size: 2rem;
    color: #00ffcc;
    margin-bottom: 15px;
    text-shadow: 
        0 0 10px rgba(0, 255, 204, 0.8),
        0 0 20px rgba(0, 255, 204, 0.6),
        0 0 30px rgba(0, 255, 204, 0.4);
}

.modal-content p {
    color: rgba(0, 255, 204, 0.9);
    font-size: 1.1rem;
    margin-bottom: 30px;
    text-shadow: 0 0 5px rgba(0, 255, 204, 0.3);
}

.modal-buttons {
    display: flex;
    gap: 15px;
    justify-content: center;
    flex-wrap: wrap;
}

.modal-btn {
    padding: 15px 25px;
    border: none;
    border-radius: 15px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    transform-style: preserve-3d;
}

.modal-btn.primary {
    background: linear-gradient(45deg, rgba(0, 255, 204, 0.3), rgba(0, 255, 204, 0.5));
    color: #00ffcc;
    border: 2px solid rgba(0, 255, 204, 0.4);
    box-shadow: 0 0 20px rgba(0, 255, 204, 0.2);
    text-shadow: 0 0 10px rgba(0, 255, 204, 0.6);
}

.modal-btn.secondary {
    background: rgba(0, 255, 204, 0.1);
    color: #00ffcc;
    border: 2px solid rgba(0, 255, 204, 0.3);
    box-shadow: 0 0 15px rgba(0, 255, 204, 0.1);
}

.modal-btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.3);
}

/* Username Input Styles */
.username-input {
    max-width: 500px;
    margin: 0 auto;
}

.username-form {
    background: rgba(0, 255, 204, 0.05);
    backdrop-filter: blur(10px);
    border: 2px solid rgba(0, 255, 204, 0.3);
    border-radius: 20px;
    padding: 40px;
    box-shadow: 
        0 0 30px rgba(0, 255, 204, 0.1),
        inset 0 0 30px rgba(0, 255, 204, 0.05);
}

.input-group {
    margin-bottom: 25px;
    text-align: left;
}

.input-group label {
    display: block;
    color: #00ffcc;
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 8px;
    text-shadow: 0 0 10px rgba(0, 255, 204, 0.6);
}

.input-group input {
    width: 100%;
    padding: 15px 20px;
    background: rgba(0, 255, 204, 0.1);
    border: 2px solid rgba(0, 255, 204, 0.3);
    border-radius: 15px;
    color: #00ffcc;
    font-size: 1rem;
    font-family: 'Roboto', sans-serif;
    transition: all 0.3s ease;
    box-shadow: 
        0 0 15px rgba(0, 255, 204, 0.1),
        inset 0 0 15px rgba(0, 255, 204, 0.05);
}

.input-group input:focus {
    outline: none;
    border-color: rgba(0, 255, 204, 0.6);
    background: rgba(0, 255, 204, 0.15);
    box-shadow: 
        0 0 25px rgba(0, 255, 204, 0.3),
        inset 0 0 25px rgba(0, 255, 204, 0.1);
    text-shadow: 0 0 10px rgba(0, 255, 204, 0.8);
}

.input-group input::placeholder {
    color: rgba(0, 255, 204, 0.5);
}

.username-buttons {
    display: flex;
    gap: 20px;
    justify-content: center;
    margin-top: 30px;
    flex-wrap: wrap;
}

.start-game-btn {
    background: linear-gradient(45deg, rgba(0, 255, 204, 0.3), rgba(0, 255, 204, 0.5));
    border: 2px solid rgba(0, 255, 204, 0.4);
    border-radius: 15px;
    padding: 15px 30px;
    color: #00ffcc;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    transform-style: preserve-3d;
    box-shadow: 0 0 20px rgba(0, 255, 204, 0.2);
    text-shadow: 0 0 10px rgba(0, 255, 204, 0.6);
}

.start-game-btn:hover {
    transform: translateY(-5px);
    background: linear-gradient(45deg, rgba(0, 255, 204, 0.4), rgba(0, 255, 204, 0.6));
    border-color: rgba(0, 255, 204, 0.6);
    box-shadow: 
        0 10px 25px rgba(0, 0, 0, 0.5),
        0 0 30px rgba(0, 255, 204, 0.4);
    text-shadow: 0 0 15px rgba(0, 255, 204, 0.8);
}

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

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

/* Responsive Design */
@media (max-width: 768px) {
    .main-title {
        font-size: 2rem;
    }
    
    .logo-container {
        flex-direction: column;
        gap: 15px;
    }
    
    .logo {
        width: 60px;
        height: 60px;
    }
    
    .cell {
        width: 80px;
        height: 80px;
        font-size: 2.5rem;
    }
    
    .mode-buttons, .difficulty-buttons {
        flex-direction: column;
        align-items: center;
    }
    
    .mode-btn, .difficulty-btn {
        min-width: 250px;
    }
    
    .game-info {
        flex-direction: column;
        text-align: center;
    }
    
    .stats-section {
        grid-template-columns: 1fr;
    }
    
    .difficulty-breakdown {
        flex-direction: column;
        align-items: center;
    }
}

@media (max-width: 480px) {
    .cell {
        width: 70px;
        height: 70px;
        font-size: 2rem;
    }
    
    .main-title {
        font-size: 1.5rem;
    }
    
    .subtitle {
        font-size: 1rem;
    }
}