:root {
    --board-bg: #000;
    --border-color: #444;
    --cell-bg: #228B22; /* DarkGreen */
    --text-color: #fff;
    --modal-bg: rgba(20, 20, 20, 0.9);
    --modal-content-bg: #1a1a1a;
    --button-bg: #333;
    --button-hover-bg: #555;
}

body {
    font-family: 'Helvetica Neue', Arial, sans-serif;
    background-color: var(--board-bg);
    color: var(--text-color);
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
    overflow: hidden;
}

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

h1 {
    margin-bottom: 20px;
    font-weight: 300;
    letter-spacing: 2px;
}

#board {
    display: grid;
    grid-template-columns: repeat(8, 1fr);
    grid-template-rows: repeat(8, 1fr);
    width: 80vmin;
    height: 80vmin;
    max-width: 500px;
    max-height: 500px;
    border: 2px solid var(--border-color);
    background-color: var(--board-bg);
    padding: 5px;
    box-shadow: 0 0 20px rgba(0, 255, 0, 0.2);
}

.cell {
    background-color: var(--cell-bg);
    border: 1px solid var(--border-color);
    display: flex;
    justify-content: center;
    align-items: center;
    cursor: pointer;
}

.disc {
    width: 80%;
    height: 80%;
    border-radius: 50%;
    transition: transform 0.3s ease, background-color 0.3s ease;
}

.black {
    background-color: #111;
    box-shadow: inset 0 0 10px rgba(255,255,255,0.2);
}

.white {
    background-color: #eee;
    box-shadow: inset 0 0 10px rgba(0,0,0,0.5);
}

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

.valid-move {
    background-color: rgba(255, 255, 255, 0.2);
    border-radius: 50%;
    width: 50%;
    height: 50%;
}

#game-info {
    display: flex;
    justify-content: space-around;
    margin-top: 20px;
    font-size: 1.2em;
}

#restart-button {
    display: none;
    margin-top: 20px;
    padding: 10px 20px;
    font-size: 1.2em;
    cursor: pointer;
    background-color: var(--button-bg);
    color: var(--text-color);
    border: 1px solid var(--border-color);
    border-radius: 5px;
    transition: background-color 0.2s;
}

#restart-button:hover {
    background-color: var(--button-hover-bg);
}

#restart-button.show {
    display: inline-block;
}

/* Modal Styles */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: var(--modal-bg);
    display: none;
    justify-content: center;
    align-items: center;
    z-index: 100;
}

.modal.show {
    display: flex;
}

.modal-content {
    background-color: var(--modal-content-bg);
    padding: 30px;
    border-radius: 10px;
    box-shadow: 0 0 25px rgba(0, 255, 0, 0.3);
    text-align: center;
    border: 1px solid var(--border-color);
}

.form-group {
    margin-bottom: 20px;
    text-align: left;
}

.form-group label {
    display: block;
    margin-bottom: 10px;
}

select, button {
    width: 100%;
    padding: 10px;
    background-color: var(--button-bg);
    color: var(--text-color);
    border: 1px solid var(--border-color);
    border-radius: 5px;
    font-size: 1em;
    cursor: pointer;
    transition: background-color 0.2s;
}

button:hover {
    background-color: var(--button-hover-bg);
}

#fireworks-canvas {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 99;
    pointer-events: none;
}

/* Responsive */
@media (max-width: 600px) {
    #board {
        width: 90vmin;
        height: 90vmin;
    }
    #game-info {
        font-size: 1em;
    }
    .modal-content {
        width: 80%;
    }
}