:root {
            --dark-background: #121212;
            --dark-card: #1e1e1e;
            --text-color: #e0e0e0;
            --highlight-color: #4a90e2;
            --highlight-secondary: #6a5acd;
            --border-color: #333;
            --font-family: 'Inter', sans-serif;
            --button-bg: #4a90e2;
            --button-text: #ffffff;
            --button-hover: #3a7bd5;
            --warning-color: #e57373;
        }

        body, html {
            height: 100%;
            margin: 0;
            font-family: var(--font-family);
            background-color: var(--dark-background);
            color: var(--text-color);
            overflow: auto; 
            overscroll-behavior-y: none;
        }

        .container {
            display: flex;
            flex-direction: column;
            align-items: center;
            justify-content: flex-start;
            min-height: 100vh;
            padding: 15px;
            box-sizing: border-box;
        }

        .header {
            text-align: center;
            margin-bottom: 5px;
            flex-shrink: 0;
            padding-top: 10px;
            width: 100%;
            position: relative;
            // max-width: 500px;
        }

        .title {
            font-size: clamp(1rem, 5vw, 1rem);
            color: var(--highlight-color);
            margin-bottom: 0px;
            font-weight: 700;
        }

        .subtitle {
            font-size: clamp(1rem, 2vw, 1rem);
            color: #aaa;
            margin-top: 0;
            margin-bottom: 5px;
        }

        #menu-icon {
            position: absolute;
            top: 10px;
            right: 0;
            background: none;
            border: none;
            cursor: pointer;
            padding: 10px;
            color: var(--text-color);
            transition: color 0.2s;
        }
        #menu-icon:hover {
            color: var(--highlight-color);
        }

        #board-container {
            width: 100%;
            // margin: 10px auto;
            // aspect-ratio: 1 / 1;
            box-shadow: 0 0 40px rgba(0, 0, 0, 0.5);
            border-radius: 8px;
            border: 5px solid var(--border-color);
            transition: max-width 0.3s ease;
            flex-shrink: 1;
        }

        .modal-overlay {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background-color: rgba(0, 0, 0, 0.85);
            display: flex;
            justify-content: center;
            align-items: center;
            z-index: 100;
            opacity: 0;
            visibility: hidden;
            transition: opacity 0.3s ease, visibility 0.3s ease;
        }

        .modal-overlay.open {
            opacity: 1;
            visibility: visible;
        }

        .modal-content {
            background-color: var(--dark-card);
            padding: 30px;
            border-radius: 12px;
            box-shadow: 0 8px 30px rgba(0, 0, 0, 0.6);
            position: relative;
            width: 90%;
            max-width: 450px;
        }
        
        #close-menu {
            position: absolute;
            top: 10px;
            right: 10px;
            background: none;
            border: none;
            color: var(--text-color);
            font-size: 1.5rem;
            cursor: pointer;
        }

        .controls-panel {
            display: flex;
            flex-direction: column;
            gap: 20px;
            margin-top: 10px;
        }

        .control-group {
            display: flex;
            justify-content: space-between;
            align-items: center;
            flex-wrap: wrap;
            gap: 10px;
            padding: 10px 0;
            border-bottom: 1px solid var(--border-color);
        }
        .control-group:last-of-type { border-bottom: none; }

        .control-group label {
            font-weight: 600;
            color: var(--highlight-secondary);
            font-size: 1rem;
            flex-grow: 1;
            min-width: 100px;
        }

        .control-buttons {
            display: flex;
            gap: 8px;
        }

        .control-button {
            padding: 8px 12px;
            border: none;
            border-radius: 9999px;
            cursor: pointer;
            font-weight: 500;
            transition: background-color 0.2s, transform 0.1s;
            background-color: var(--border-color);
            color: var(--text-color);
            min-width: 80px;
        }

        .control-button.selected {
            background-color: var(--highlight-color);
            color: var(--button-text);
            box-shadow: 0 2px 5px rgba(0, 0, 0, 0.3);
        }

        .control-button:hover:not(.selected) {
            background-color: #555;
        }
        
        .control-button:active {
            transform: scale(0.98);
        }
        
        .info-panel {
            background-color: var(--dark-card);
            padding: 15px;
            border-radius: 8px;
            box-shadow: 0 4px 10px rgba(0, 0, 0, 0.3);
            margin-top: 5px;
            width: 100%;
            max-width: 450px;
            // max-height: 120px; 
            font-size: 0.9rem;
            line-height: 1.4;
            border: 1px solid var(--border-color);
            flex-shrink: 0;
            display: flex;
            flex-direction: column;
            box-sizing: border-box;
        }
        
        #auto-restart-timer {
            font-size: 1.1rem;
            font-weight: 700;
            color: var(--warning-color); 
            margin-top: 10px;
            text-align: center;
        }

        .current-status {
            font-weight: bold;
            color: var(--highlight-color);
            // margin-bottom: 5px;
            flex-shrink: 0;
        }
        
        #pgn-history {
            flex-grow: 1;
            overflow-y: auto;
            white-space: pre-wrap;
            padding-right: 5px;
        }

        .board-b72b1 {
            background-image: url('assets/board.png'); 
            background-size: cover;
            border-radius: 4px;
        }
        .square-55d63 { background: rgba(255, 255, 255, 0); }
        .square-last-move { background-color: rgba(106, 90, 205, 0.5) !important; }

        .message-box {
            position: fixed;
            bottom: 20px;
            left: 50%;
            transform: translateX(-50%);
            z-index: 1000;
            padding: 1rem 1.5rem;
            border-radius: 0.5rem;
            font-weight: 600;
            box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -2px rgba(0, 0, 0, 0.06);
            cursor: pointer;
            transition: opacity 0.3s ease;
            opacity: 0;
            pointer-events: none;
        }
        .message-box.show {
            opacity: 1;
            pointer-events: auto;
        }

        @media (max-width: 600px) {
             .container {
                justify-content: flex-start; 
                padding-top: 5px;
            }
            .modal-content {
                padding: 20px;
            }
            .controls-panel {
                gap: 15px;
            }
            .control-group {
                flex-direction: column;
                align-items: flex-start;
            }
            .control-buttons {
                width: 100%;
                justify-content: stretch;
            }
            .control-button {
                flex: 1;
            }
            #menu-icon {
                top: 5px;
            }
        }

        #start-new-game {
                background-color: #949494;
                z-index: 18;
                border-radius: 9999px;
        }

        #swipe-handle {
            position: relative;
            left: 0;
            top: 0;
            width: 25%;	
            align-items: center;
            justify-content: center;
            cursor: pointer;
            border-radius: 9999px;
            z-index: 20;
            transition: transform 0.3s cubic-bezier(0.18, 0.89, 0.32, 1.28); /* Smooth snap-back */
            background-color: #3b82f6; /* Blue 500 */
            color: white;
        }