:root {
    --background-gradient: linear-gradient(135deg, #333 0%, #555 100%);
    --light-cell-color: #f0d9b5;
    --dark-cell-color: #b58863;
    --highlight-color: #7fc97f;
    --board-border-color: #333;
    --button-bg-color: #667eea;
    --current-player-color: #667eea;
    --button-hover-bg-color: #5568d3;
}

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

body {
    font-family: 'Arial', sans-serif;
    background: var(--background-gradient);
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    padding: 20px;
}

.container {
    background: white;
    border-radius: 15px;
    padding: 30px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
    text-align: center;
}

h1 {
    color: #333;
    margin-bottom: 20px;
}

.game-info {
    margin-bottom: 20px;
    font-size: 18px;
    color: #555;
}

#current-player {
    font-weight: bold;
    color: var(--current-player-color);
}

#chessboard {
    display: grid;
    grid-template-columns: repeat(8, 60px);
    grid-template-rows: repeat(8, 60px);
    gap: 0;
    margin: 0 auto 20px;
    border: 3px solid #333;
}

.cell {
    width: 60px;
    height: 60px;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 40px;
    cursor: pointer;
    transition: background-color 0.2s;
}

.cell img {
    pointer-events: none;
    width: 45px;
    height: 60px;
}

.cell.light {
    background-color: var(--light-cell-color);
}

.cell.dark {
    background-color: var(--dark-cell-color);
}

.cell.selected {
    background-color: var(--highlight-color);
}

.cell.possible-move {
    position: relative;
}

.cell.possible-move::after {
    content: '';
    position: absolute;
    top: 25%;
    left: 25%;
    width: 50%;
    height: 50%;
    background-color: rgba(0, 0, 0, 0.4);
    border-radius: 50%;
}

.cell:hover {
    opacity: 0.8;
}

.controls {
    margin-top: 20px;
}

#reset-btn {
    padding: 12px 30px;
    font-size: 16px;
    background-color: var(--button-bg-color);
    color: white;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    transition: background-color 0.3s;
}

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

.promotion-tooltip {
    display: flex;
    gap: 8px;
    background: #fefefe;
    border: 2px solid #333;
    border-radius: 8px;
    padding: 6px 8px;
    position: absolute;
    z-index: 1000;
    box-shadow: 0 2px 6px rgba(0,0,0,0.4);
  }
  
  .promotion-option {
    display: flex;
    flex-direction: column;
    align-items: center;
    cursor: pointer;
    transition: transform 0.1s ease;
  }
  
  .promotion-option:hover {
    transform: scale(1.1);
    background-color: #eee;
  }
  
  .promotion-icon {
    width: 40px;
    height: 40px;
    object-fit: contain;
  }