body {
    font-family: sans-serif;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    background-color: #282c34;
    color: white;
}

#game-board {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    grid-template-rows: repeat(3, 1fr);
    width: 600px;
    height: 600px;
    border: 3px solid #61dafb;
    background-color: #3c4049;
}

.small-board {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    grid-template-rows: repeat(3, 1fr);
    border: 2px solid #555;
    position: relative;
}

.cell {
    border: 1px solid #444;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 3em;
    cursor: pointer;
    transition: background-color 0.3s;
}

.cell:hover {
    background-color: #4a505a;
}

.small-board.active {
    background-color: #3c4d3d;
}

.small-board.active .cell:hover {
    background-color: #5a705c;
}

.cell.X { color: #61dafb; }
.cell.O { color: #e06c75; }

.small-board .winner-overlay {
    position: absolute;
    top: 0; left: 0; right: 0; bottom: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 10em;
    pointer-events: none;
    color: rgba(255, 255, 255, 0.5);
}

#status-area {
    margin: 20px 0;
    text-align: center;
}

#status-text {
    font-size: 1.5em;
    min-height: 1.5em;
}

button {
    margin-top: 20px;
    padding: 10px 20px;
    font-size: 1em;
    cursor: pointer;
    background-color: #61dafb;
    border: none;
    border-radius: 5px;
    color: #282c34;
    font-weight: bold;
}

.subtitle {
    font-size: 1em;
    font-weight: normal;
    color: #ccc;
    text-align: center;
    max-width: 600px;
    margin: -10px 0 20px 0;
}

footer {
    margin-top: 40px;
    font-size: 0.9em;
    color: #888;
}

#depth-control {
    margin: 20px 0;
    display: flex;
    align-items: center;
    gap: 10px;
}

#depth-control button {
    margin: 0;
    padding: 5px 10px;
    font-size: 1.2em;
    min-width: 40px;
}

#depth-display {
    font-size: 1.2em;
    color: #61dafb;
    font-weight: bold;
    min-width: 120px;
    text-align: center;
}

#depth-control button:disabled {
    background-color: #555;
    color: #888;
    cursor: not-allowed;
    opacity: 0.6;
}

#depth-display {
    font-size: 1.2em;
    color: #61dafb;
    font-weight: bold;
    min-width: 140px; /* Increased width to accommodate "(locked)" text */
    text-align: center;
}