body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
    background-color: #2c3e50; /* Dark slate blue background */
    color: #ecf0f1; /* Light text color */
}

.trainer-container {
    background: #34495e; /* Slightly lighter slate for the container */
    padding: 30px 40px;
    border-radius: 12px;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.4);
    text-align: center;
    width: 90%;
    max-width: 450px;
    border: 1px solid #46627f;
}

h1 {
    margin-top: 0;
    color: #ffffff;
}

.controls {
    display: flex;
    justify-content: space-around;
    gap: 20px;
    margin: 25px 0;
    flex-wrap: wrap;
}

.control-group {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
}

label {
    font-weight: 600;
    font-size: 0.9em;
}

input[type="number"], select {
    padding: 8px 12px;
    border-radius: 6px;
    border: 1px solid #7f8c8d;
    font-size: 1em;
    width: 80px;
    text-align: center;
    background-color: #2c3e50;
    color: #ecf0f1;
}

.metronome-control {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 8px;
    margin-bottom: 20px;
}

.metronome-control label {
    cursor: pointer;
}

#start-stop-btn {
    width: 100%;
    padding: 12px 20px;
    font-size: 1.1em;
    font-weight: bold;
    color: #fff;
    background-color: #3498db; /* Bright blue for start button */
    border: none;
    border-radius: 8px;
    cursor: pointer;
    transition: background-color 0.2s;
}

#start-stop-btn:hover {
    background-color: #2980b9;
}

#start-stop-btn.active {
    background-color: #e74c3c; /* Red for stop button */
}

#start-stop-btn.active:hover {
    background-color: #c0392b;
}

#note-display {
    font-size: 8em;
    font-weight: bold;
    margin-bottom: 25px;
    color: #ffffff; /* Match the bright blue button */
    min-height: 150px;
    display: flex;
    justify-content: center;
    align-items: center;
}