body {
    margin: 0;
    font-family: Arial, sans-serif;
    background-color: #f9f9f9;
    color: #333333;
}

header {
    padding: 20px;
    text-align: center;
    background-color: #fff;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

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

.container {
    max-width: 600px;
    margin: 20px auto;
    padding: 0 20px;
}

.timer-card {
    background-color: #fff;
    padding: 20px;
    border-radius: 8px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
    text-align: center;
}

.timer-display {
    font-family: 'Courier New', Courier, monospace;
    font-size: 28px;
    color: #333333;
    margin: 20px 0;
    transition: color 0.3s ease;
}

.timer-display.warning {
    color: #e74c3c;
}

.timer-input {
    margin-bottom: 20px;
}

.timer-input input {
    padding: 10px;
    font-size: 16px;
    width: 100px;
    border: 1px solid #ccc;
    border-radius: 4px;
    margin-right: 10px;
}

.timer-input button,
.timer-controls button {
    padding: 10px 20px;
    font-size: 16px;
    background-color: #2ecc71;
    color: #fff;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    transition: background-color 0.3s ease;
}

.timer-input button:hover,
.timer-controls button:hover {
    background-color: #27ae60;
}

.timer-controls button:disabled {
    background-color: #ccc;
    cursor: not-allowed;
}

.timer-controls {
    display: flex;
    justify-content: center;
    gap: 10px;
}

@media (max-width: 600px) {
    h1 {
        font-size: 20px;
    }

    .timer-card {
        padding: 15px;
    }

    .timer-display {
        font-size: 24px;
    }

    .timer-input input {
        width: 80px;
    }

    .timer-input button,
    .timer-controls button {
        padding: 8px 16px;
        font-size: 14px;
    }
}