body {
    display: flex;
    justify-content: center;
    align-items: center;
    background: linear-gradient(135deg, #1e1e1e 0%, #111 100%);
    overflow: hidden;
}

.overlay {
    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;
}

.container {
    text-align: center;
    background: rgba(0, 0, 0, 0.9);
    padding: 20px;
    border-radius: 15px;
    box-shadow: 0 0 20px rgba(0, 255, 0, 0.8);
    width: 90%;
    max-width: 500px;
    animation: fadeIn 1.5s ease-in-out;
}

h1 {
    font-size: 2.5em;
    color: #0f0; /* Neon green */
    margin-bottom: 20px;
    text-shadow: 0 0 10px #0f0;
    animation: fadeIn 1.5s ease-in-out;
}

#game-board {
    display: grid;
    grid-template-columns: repeat(5, 60px);
    grid-template-rows: repeat(5, 60px);
    gap: 10px;
    margin: 20px auto;
    justify-content: center;
    animation: fadeIn 1.5s ease-in-out;
}

.cell {
    width: 60px;
    height: 60px;
    border-radius: 10px;
    display: flex;
    justify-content: center;
    align-items: center;
    cursor: pointer;
    background-color: #222;
    border: 2px solid #0f0;
    transition: background-color 0.3s, transform 0.2s, box-shadow 0.3s;
    box-shadow: 0 0 10px rgba(0, 255, 0, 0.6);
}

.cell:hover {
    transform: scale(1.1);
}

.cell.active {
    background-color: #0f0; /* Neon green */
    color: #222;
    box-shadow: 0 0 20px rgba(0, 255, 0, 1);
}

#controls {
    margin-top: 20px;
    animation: fadeIn 1.5s ease-in-out;
}

button {
    background-color: #0f0; /* Neon green */
    color: #222;
    border: none;
    padding: 10px 20px;
    font-size: 1em;
    border-radius: 5px;
    cursor: pointer;
    transition: background-color 0.3s, transform 0.2s, box-shadow 0.3s;
    box-shadow: 0 0 10px rgba(0, 255, 0, 0.8);
}

button:hover {
    background-color: #0d0;
    transform: scale(1.1);
    box-shadow: 0 0 20px rgba(0, 255, 0, 1);
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(-10px); }
    to { opacity: 1; transform: translateY(0); }
}