:root {
    --primary-color: #6d5dfc;
    --background-color: #e0e5ec;
    --text-color: #555;
    --light-shadow: rgba(255, 255, 255, 0.9);
    --dark-shadow: rgba(0, 0, 0, 0.15);
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--background-color);
    color: var(--text-color);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
}

.container {
    max-width: 900px;
    margin: 20px auto;
    padding: 20px;
}

/* Header Styling */
.page-header {
    text-align: center;
    padding: 20px 0;
    margin-bottom: 20px;
}

.page-header h1 {
    font-size: 2.8rem;
    color: var(--primary-color);
    font-weight: 700;
}

.page-header p {
    font-size: 1.1rem;
    color: var(--text-color);
}

/* Neumorphism Styling */
.neumorphic {
    border-radius: 20px;
    background: var(--background-color);
    box-shadow: 8px 8px 15px var(--dark-shadow), -8px -8px 15px var(--light-shadow);
}

.neumorphic-inset {
    border-radius: 15px;
    background: var(--background-color);
    box-shadow: inset 5px 5px 10px var(--dark-shadow), inset -5px -5px 10px var(--light-shadow);
}

.main-content {
    padding: 30px;
}

.game-controls {
    display: flex;
    justify-content: center;
    gap: 15px;
    margin-bottom: 30px;
    flex-wrap: wrap;
    align-items: center;
}

.control-btn, .difficulty-select {
    border: none;
    padding: 12px 24px;
    border-radius: 50px;
    cursor: pointer;
    font-weight: 600;
    transition: all 0.3s ease;
    color: var(--text-color);
    background: var(--background-color);
    box-shadow: 5px 5px 10px var(--dark-shadow), -5px -5px 10px var(--light-shadow);
}

.control-btn:hover, .difficulty-select:hover {
    color: var(--primary-color);
    box-shadow: 3px 3px 6px var(--dark-shadow), -3px -3px 6px var(--light-shadow);
}

.control-btn:active {
    box-shadow: inset 3px 3px 6px var(--dark-shadow), inset -3px -3px 6px var(--light-shadow);
}

.game-area {
    display: flex;
    gap: 20px;
    flex-wrap: wrap;
    justify-content: center;
}

.game-info {
    padding: 20px;
    margin-bottom: 20px;
    text-align: center;
}

.game-info span {
    display: block;
    margin-bottom: 10px;
    font-weight: 600;
}

.chess-board {
    display: grid;
    /* UPDATED: Use 1fr to divide space equally */
    grid-template-columns: repeat(8, 1fr);
    grid-template-rows: repeat(8, 1fr);
    
    /* UPDATED: Responsive width and aspect ratio */
    width: min(90vw, 480px); /* 90% of viewport width, capped at 480px */
    aspect-ratio: 1 / 1; /* Ensures the board is always a perfect square */
    border: none;
}

.chess-square {
    /* REMOVED: width and height are now controlled by the grid */
    display: flex;
    align-items: center;
    justify-content: center;
    
    /* UPDATED: Responsive font size */
    font-size: min(7vw, 36px); /* Scales with screen, capped at 36px */
    cursor: pointer;
    position: relative;
}


.chess-square.light { background-color: #f0d9b5; }
.chess-square.dark { background-color: #b58863; }

.chess-square.selected {
    background-color: #7efc85 !important;
}

.chess-square.valid-move::after {
    content: '';
    position: absolute;
    width: 20px;
    height: 20px;
    background: rgba(0, 0, 0, 0.3);
    border-radius: 50%;
}

.king-in-check {
     background-color: #ff7675 !important;
}

.side-panel {
    flex-basis: 220px;
    padding: 20px;
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.captured-pieces h4, .moves-list h4 {
    margin-bottom: 10px;
    text-align: center;
}

.pieces-display, #movesDisplay {
    min-height: 80px;
    padding: 10px;
    overflow-y: auto;
    max-height: 150px;
    word-break: break-word;
}

/* Footer Styling */
.page-footer {
    text-align: center;
    padding: 20px 0;
    margin-top: 20px;
    font-size: 0.9rem;
    }