body {
    font-family: 'Arial', sans-serif;
    background-color: #f0f2f5;
    margin: 0;
    padding: 20px;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    background-color: #ffffff;
    padding: 20px;
    border-radius: 10px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

h1 {
    color: #1a73e8;
    text-align: center;
    margin-bottom: 30px;
}

.calculator {
    max-width: 300px;
    margin: 0 auto;
}

#display {
    width: 100%;
    height: 40px;
    margin-bottom: 10px;
    font-size: 20px;
    text-align: right;
    padding: 5px;
    border: 1px solid #ddd;
    border-radius: 5px;
}

.buttons {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 5px;
}

button {
    padding: 15px;
    font-size: 18px;
    border: none;
    background-color: #e8f0fe;
    color: #1a73e8;
    border-radius: 5px;
    cursor: pointer;
    transition: background-color 0.2s;
}

button:hover {
    background-color: #d2e3fc;
}

.links {
    text-align: center;
    margin-top: 20px;
}

.links a {
    color: #1a73e8;
    text-decoration: none;
}

.links a:hover {
    text-decoration: underline;
}