body {
            font-family: 'Inter', sans-serif;
            background-color: #f0f4f8; /* Light blue-gray background */
            display: flex;
            justify-content: center;
            align-items: center;
            min-height: 100vh;
            margin: 0;
            padding: 20px;
            box-sizing: border-box;
        }
        .container {
            background-color: #ffffff;
            border-radius: 1.5rem; /* More rounded corners */
            box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
            padding: 2rem;
            max-width: 900px;
            width: 100%;
            text-align: center;
            border: 1px solid #e2e8f0; /* Subtle border */
        }
        .instrument-button {
            transition: all 0.2s ease-in-out;
            border: 2px solid transparent;
        }
        .instrument-button.active {
            background-color: #10b981; /* Green for active */
            color: white;
            transform: translateY(-2px);
            box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
            border-color: #059669;
        }
        .instrument-button:not(.active) {
            background-color: #cbd5e1; /* Light gray for inactive */
            color: #4a5568;
        }
        .instrument-button:hover:not(.active) {
            background-color: #a0aec0; /* Darker gray on hover */
            color: white;
        }
        .instrument-button:hover.active {
            background-color: #059669; /* Darker green on hover */
        }
        input[type="range"] {
            -webkit-appearance: none;
            width: 100%;
            height: 10px;
            background: #e2e8f0;
            border-radius: 5px;
            outline: none;
            opacity: 0.7;
            transition: opacity .2s;
            margin-top: 1rem;
        }
        input[type="range"]::-webkit-slider-thumb {
            -webkit-appearance: none;
            appearance: none;
            width: 20px;
            height: 20px;
            background: #4c51bf; /* Indigo for thumb */
            border-radius: 50%;
            cursor: pointer;
            box-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
        }
        input[type="range"]::-moz-range-thumb {
            width: 20px;
            height: 20px;
            background: #4c51bf;
            border-radius: 50%;
            cursor: pointer;
            box-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
        }
        .play-pause-button {
            background-color: #4c51bf; /* Indigo */
            color: white;
            transition: all 0.2s ease-in-out;
        }
        .play-pause-button:hover {
            background-color: #363b90; /* Darker indigo */
            transform: translateY(-2px);
            box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
        }
        .beat-indicator {
            min-width: 30px;
            height: 30px;
            line-height: 30px;
            background-color: #fbd38d; /* Light orange */
            color: #c05621; /* Dark orange text */
            font-weight: bold;
            border-radius: 0.75rem;
            display: inline-flex; /* Use flex to center content */
            justify-content: center;
            align-items: center;
            margin: 0 0.5rem;
            transition: all 0.1s ease-out;
            transform: scale(0.9);
        }
        .beat-indicator.current {
            background-color: #f6ad55; /* Darker orange for current beat */
            transform: scale(1.1);
            box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
        }