body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
    margin: 0;
    padding: 20px;
    background-color: #f0f4f8;
    display: flex;
    justify-content: center;
    align-items: flex-start;
}

#focus-flow-app {
    width: 300px;
    background-color: white;
    border-radius: 20px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    overflow: hidden;
    padding: 20px;
}

h1 {
    font-size: 24px;
    font-weight: bold;
    margin: 0 0 20px 0;
}

/* ... (previous CSS remains the same) */

#timer-container {
    background-color: #3498db;
    border-radius: 12px;
    padding: 20px;
    text-align: center;
    color: white;
    margin-bottom: 20px;
}

#timer {
    font-size: 48px;
    font-weight: 700; /* Increased font weight for boldness */
    margin: 0;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
    /* The system font stack above includes fonts that are generally more rounded */
    letter-spacing: -1px; /* Slightly tighten letter spacing */
}

/* ... (rest of the CSS remains the same) */

button {
    width: 100%;
    padding: 15px;
    background-color: #2ecc71;
    color: white;
    border: none;
    border-radius: 12px;
    cursor: pointer;
    font-size: 16px;
    margin-bottom: 10px;
    transition: background-color 0.3s ease;
    font-weight: 500;
}

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

button:disabled {
    background-color: #bdc3c7;
    cursor: not-allowed;
}

#settings {
    margin-top: 20px;
}

.switch {
    position: relative;
    display: inline-block;
    width: 50px;
    height: 24px;
    margin-right: 10px;
    vertical-align: middle;
}

.switch input {
    opacity: 0;
    width: 0;
    height: 0;
}

.slider {
    position: absolute;
    cursor: pointer;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: #ccc;
    transition: .4s;
    border-radius: 34px;
}

.slider:before {
    position: absolute;
    content: "";
    height: 20px;
    width: 20px;
    left: 2px;
    bottom: 2px;
    background-color: white;
    transition: .4s;
    border-radius: 50%;
}

input:checked + .slider {
    background-color: #3498db;
}

input:checked + .slider:before {
    transform: translateX(26px);
}

.focus-duration-setting {
    margin-top: 15px;
    display: flex;
    align-items: center;
}

#focus-duration {
    width: 50px;
    margin-left: 10px;
    padding: 5px;
    font-size: 14px;
    border: 1px solid #ccc;
    border-radius: 4px;
}

.hidden {
    display: none;
}

#game-container {
    margin-top: 20px;
    border: 1px solid #e0e0e0;
    border-radius: 8px;
    padding: 15px;
}

#pongCanvas {
    border: 1px solid #ccc;
    max-width: 100%;
    height: auto;
}

label {
    font-size: 14px;
    color: #555;
}