/* Center all text */
body {
    text-align: center;
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    background-color: #f4f4f4;
}

#timer-display {
    font-size: 48px;
    font-weight: bold;
    margin: 20px 0;
}

button {
    margin: 0 10px;
    padding: 10px 20px;
    font-size: 1rem;
    cursor: pointer;
    border: none;
    border-radius: 4px;
    background-color: #007BFF;
    color: white;
    transition: background-color 0.3s;
}

button:hover {
    background-color: #0056b3;
}

.start {
    background-color: #4CAF50;
    color: white;
}

.stop {
    background-color: #f44336;
    color: white;
}

.container {
    max-width: 600px;
    width: 100%;
    padding: 20px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
    background: white;
    border-radius: 8px;
}

h1, h3 {
    margin: 0 0 20px;
}

.controls {
    margin: 20px 0;
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.control-group {
    display: flex;
    flex-direction: column;
    gap: 5px;
}

label {
    font-weight: bold;
}

.slider-container {
    margin: 20px 0;
    display: flex;
    align-items: center;
    gap: 10px;
}

input[type="range"] {
    flex-grow: 1;
}

.value-display {
    min-width: 60px;
    text-align: right;
}

.preset-buttons {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-top: 15px;
}

.preset-button {
    flex: 1 1 calc(33% - 10px);
    min-width: 120px;
    background-color: #2ecc71;
}

.preset-button:hover {
    background-color: #27ae60;
}

.info {
    font-size: 2rem;
    margin: 20px 0;
    padding: 15px;
    background-color: #ecf0f1;
    border-radius: 5px;
}

.frequency-info {
    margin-top: 10px;
}

.waveform-container {
    position: relative;
    height: 100px;
    background-color: #ecf0f1;
    border-radius: 5px;
    overflow: hidden;
    margin: 20px 0;
}

.waveform {
    position: absolute;
    width: 100%;
    height: 100%;
}

#volume-slider {
    margin-top: 15px;
}