body {
    font-family: 'Arial', sans-serif;
    background-color: #f0f0f0;
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 20px;
}

.add, .table, .start {
    background-color: white;
    border-radius: 8px;
    padding: 20px;
    margin-bottom: 20px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    width: 80%;
    max-width: 600px;
}

input, button {
    padding: 10px;
    margin: 5px;
    border: 1px solid #ddd;
    border-radius: 4px;
}

button {
    background-color: #4CAF50;
    color: white;
    border: none;
    cursor: pointer;
    transition: background-color 0.3s;
}

button:hover {
    background-color: #45a049;
}

table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 10px;
}

th, td {
    border: 1px solid #ddd;
    padding: 8px;
    text-align: left;
}

th {
    background-color: #f2f2f2;
}

#items tr:nth-child(even) {
    background-color: #f9f9f9;
}

#result tr {
    background-color: #e6f7ff;
}

.start button {
    width: 48%;
    margin: 1%;
}

@media (max-width: 600px) {
    .add, .table, .start {
        width: 95%;
    }
}