/* General Styling */
body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: #f4f4f9;
    display: flex;
    justify-content: center;
    align-items: center;
    flex-direction: column;
    min-height: 100vh;
    margin: 0;
}

h1 {
    color: #333;
    margin-bottom: 20px;
    font-size: 2.5rem;
}

/* Game Board */
.game-board {
    display: grid;
    grid-template-columns: repeat(3, 120px);
    grid-gap: 15px;
    justify-content: center;
    margin: 20px auto;
}

.cell {
    width: 120px;
    height: 120px;
    background-color: #fff;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 3rem;
    color: #333;
    border: 4px solid #5c6bc0;
    border-radius: 15px;
    transition: background-color 0.3s ease;
    cursor: pointer;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

.cell:hover {
    background-color: #e8eaf6;
}

/* Reset Button */
#reset-btn {
    margin-top: 20px;
    padding: 10px 25px;
    background-color: #5c6bc0;
    color: white;
    font-size: 1rem;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    transition: background-color 0.3s ease;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

#reset-btn:hover {
    background-color: #3f51b5;
}

/* Popup Styling */
.popup {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.6);
    justify-content: center;
    align-items: center;
}

.popup-content {
    background-color: #fff;
    padding: 30px;
    border-radius: 12px;
    text-align: center;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
}

#popup-message {
    font-size: 1.5rem;
    margin-bottom: 20px;
    display: block;
}

#popup-close {
    padding: 10px 20px;
    background-color: #5c6bc0;
    color: white;
    font-size: 1rem;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    transition: background-color 0.3s ease;
}

#popup-close:hover {
    background-color: #3f51b5;
}