.timer {
    font-family: Arial, sans-serif;
    text-align: center;
    padding: 20px;
    background-color: #f5f5f5;
    border-radius: 10px;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
    max-width: 600px;
    margin: 50px auto;
}

.display {
    display: flex;
    justify-content: center;
    gap: 20px;
    margin-bottom: 20px;
}

.unit {
    display: flex;
    flex-direction: column;
    align-items: center;
    background-color: white;
    padding: 15px;
    border-radius: 8px;
    min-width: 80px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.num {
    font-size: 2.5em;
    font-weight: bold;
    color: #333;
}

.text {
    font-size: 1em;
    color: #666;
    margin-top: 5px;
}

.settings {
    display: flex;
    justify-content: center;
    gap: 10px;
    margin-top: 20px;
}

.input {
    padding: 8px;
    border: 1px solid #ddd;
    border-radius: 4px;
    font-size: 1em;
}

.btn {
    padding: 8px 16px;
    background-color: #4CAF50;
    color: white;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-size: 1em;
    transition: background-color 0.3s;
}

.btn:hover {
    background-color: #45a049;
}

.time-up {
    display: none;
    font-size: 2em;
    color: #ff0000;
    font-weight: bold;
    margin: 20px 0;
    animation: blink 1s infinite;
}

@keyframes blink {
    0% { opacity: 1; }
    50% { opacity: 0.5; }
    100% { opacity: 1; }
}