body {
    font-family: Arial, sans-serif;
    text-align: center;
    background-color: blueviolet;
}
.container {
    font-size: 24px;
    margin: 20px;
}
.calc-container {
    width: 300px;
    margin: auto;
    background: #fff;
    padding: 20px;
    border-radius: 10px;
    box-shadow: 0px 0px 10px rgba(0, 0, 0, 0.2);
}
#display {
    width: 100%;
    height: 50px;
    font-size: 20px;
    text-align: right;
    margin-bottom: 10px;
    padding: 10px;
    border: 1px solid #121212;
    border-radius: 5px;
}
.buttons {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 5px;
}
button {
    font-size: 18px;
    padding: 10px;
    border: none;
    cursor: pointer;
    background: red;
    border-radius: 5px;
}
button:hover {
    background: #d3d3d3;
}
.history {
    margin-top: 15px;
    padding: 10px;
    background: #fff;
    border-radius: 5px;
    box-shadow: 0px 0px 5px rgba(0, 0, 0, 0.2);
    max-height: 150px;
    overflow-y: auto;
    text-align: left;
}
.history div {
    padding: 5px;
    border-bottom: 1px solid #ddd;
    cursor: pointer;
}
.history div:hover {
    background: #f0f0f0;