body {
    font-family: 'Arial', sans-serif;
    background: linear-gradient(135deg, #1e90ff, #70a1ff);
    min-height: 100vh;
    margin: 0;
    display: flex;
    justify-content: center;
    align-items: center;
}

.container {
    text-align: center;
    margin-top: 50px;
    background: rgba(255, 255, 255, 0.9);
    padding: 2rem;
    border-radius: 15px;
    box-shadow: 0 8px 16px rgba(0, 0, 0, 0.2);
}

h1 {
    color: #2c3e50;
    margin-bottom: 2rem;
    font-size: 2.5rem;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.1);
}

#game-board {
    display: grid;
    grid-template-columns: repeat(3, 100px);
    grid-gap: 10px;
    margin: 20px auto;
    width: 320px;
}

.cell {
    width: 100px;
    height: 100px;
    background: white;
    border: none;
    border-radius: 10px;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 48px;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
}

.cell:hover {
    transform: scale(1.05);
    box-shadow: 0 6px 12px rgba(0, 0, 0, 0.15);
}

.cell.x {
    color: #e74c3c;
}

.cell.o {
    color: #3498db;
}

#status {
    margin: 20px 0;
    font-size: 24px;
    color: #2c3e50;
    height: 40px;
}

#reset-btn {
    padding: 12px 30px;
    font-size: 18px;
    cursor: pointer;
    background: #3498db;
    color: white;
    border: none;
    border-radius: 25px;
    transition: all 0.3s ease;
}

#reset-btn:hover {
    background: #2980b9;
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
}

.winning-cell {
    background: #2ecc71 !important;
    color: white !important;
    animation: winner 0.5s ease-in-out;
}

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

@keyframes pop {
    0% { transform: scale(1); }
    50% { transform: scale(1.2); }
    100% { transform: scale(1); }
}

.game-mode {
    margin-bottom: 20px;
}

.mode-btn {
    padding: 10px 20px;
    margin: 0 10px;
    font-size: 16px;
    cursor: pointer;
    background: #95a5a6;
    color: white;
    border: none;
    border-radius: 20px;
    transition: all 0.3s ease;
}

.mode-btn.active {
    background: #3498db;
    transform: scale(1.05);
}

.mode-btn:hover {
    transform: scale(1.05);
}