:root {
    --neon-blue: #00e5ff;
    --neon-pink: #ff4081;
    --dark-bg: #0b0c10;
    --light-bg: #1f2833;
    --text-color: #c5c6c7;
}

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

body {
    background: radial-gradient(ellipse at bottom, #1b2735 0%, #090a0f 100%);
    color: var(--text-color);
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
    padding: 20px;
}

.header {
    position: absolute;
    top: 20px;
    font-size: 1.1em;
    color: var(--neon-blue);
    text-shadow: 0 0 5px var(--neon-blue), 0 0 10px var(--neon-blue);
    animation: pulse 2s infinite;
}

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

.game-title {
    margin-bottom: 10px;
    font-size: 3em;
    color: var(--neon-pink);
    text-shadow: 0 0 10px var(--neon-pink), 0 0 20px var(--neon-pink);
}

.game-status {
    font-size: 1.5em;
    margin-bottom: 20px;
    height: 30px;
    color: #fff;
}

.game-grid {
    display: grid;
    grid-template-columns: repeat(3, 100px);
    grid-template-rows: repeat(3, 100px);
    gap: 10px;
}

.cell {
    width: 100px;
    height: 100px;
    background-color: var(--light-bg);
    border: 2px solid var(--neon-blue);
    border-radius: 10px;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 4em;
    font-weight: bold;
    cursor: pointer;
    transition: background-color 0.3s, box-shadow 0.3s;
}

.cell:hover {
    background-color: #2a3a4a;
    box-shadow: 0 0 15px var(--neon-blue);
}

.cell.x, .cell.o {
    cursor: not-allowed;
}

.cell.x::before {
    content: 'X';
    color: var(--neon-pink);
    text-shadow: 0 0 15px var(--neon-pink);
}

.cell.o::before {
    content: 'O';
    color: var(--neon-blue);
    text-shadow: 0 0 15px var(--neon-blue);
}

.winning-message {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(0, 0, 0, 0.9);
    flex-direction: column;
    justify-content: center;
    align-items: center;
    color: white;
    font-size: 4rem;
    text-align: center;
}

.winning-message.show {
    display: flex;
}

#restartButton {
    margin-top: 25px;
    padding: 15px 30px;
    font-size: 1.2em;
    color: #fff;
    background-color: var(--neon-pink);
    border: none;
    border-radius: 8px;
    cursor: pointer;
    transition: background-color 0.3s, transform 0.3s, box-shadow 0.3s;
    text-shadow: 0 0 5px #fff;
    border: 2px solid var(--neon-pink);
}

#restartButton:hover {
    background-color: #d81b60;
    box-shadow: 0 0 20px var(--neon-pink);
    transform: scale(1.05);
}

@keyframes pulse {
    0% {
        transform: scale(1);
        opacity: 0.9;
    }
    50% {
        transform: scale(1.02);
        opacity: 1;
    }
    100% {
        transform: scale(1);
        opacity: 0.9;
    }
}