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

body {
    font-family: Arial, sans-serif;
    background-color: #f0f0f0;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
}

.container {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 20px;
}

h1 {
    color: #333;
}

.chessboard {
    display: grid;
    grid-template-columns: repeat(8, 60px);
    grid-template-rows: repeat(8, 60px);
    gap: 0;
    border: 2px solid #333;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
}

.square {
    width: 60px;
    height: 60px;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 32px;
    font-weight: bold;
    cursor: pointer;
    user-select: none;
}

.square.light {
    background-color: #f0d9b5;
}

.square.dark {
    background-color: #b58863;
}

.square:hover {
    opacity: 0.8;
}

/* selection and legal-move highlights */
.square.selected {
    outline: 3px solid rgba(0, 120, 215, 0.9);
}
.square.highlight {
    box-shadow: inset 0 0 0 3px rgba(0, 200, 0, 0.35);
}