body {
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    background-color: #f0f0f0;
    font-family: Arial, sans-serif;
}
.container {
    background-color: #fff;
    padding: 20px;
    border-radius: 10px;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
}
.screen {
    width: 100%;
    background-color: #fff;
    color: #222;
    text-align: right;
    padding: 10px;
    box-sizing: border-box;
    position: relative;
}

.screen-content {
    display: inline-block;
    width: 100%;
    height: 100%;
    white-space: nowrap;
    overflow: hidden;
    font-size: 2em;
    text-align: right;
}
.cursor {
    display: inline-block;
    width: 2px;
    height: 1em;
    background-color: #222;
    animation: blink 1s step-end infinite;
}

@keyframes blink {
    from, to {
        opacity: 1;
    }
    50% {
        opacity: 0;
    }
}
.buttons {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 10px;
}
button {
    padding: 20px;
    font-size: 1.5em;
    border: none;
    border-radius: 5px;
    background-color: #e0e0e0;
    cursor: pointer;
    transition: background-color 0.3s;
}
button.operator {
    background-color: #41d130;
    color: #fff;
}
button:hover {
    background-color: #d0d0d0;
}
button.operator:hover {
    background-color: #29841e;
}

#history {
    margin-left: 20px;
    padding: 10px;
    background-color: #f1f1f1;
    border: 1px solid #ccc;
    height: 150px;
    overflow-y: auto;
    font-family: monospace;
}

.hidden {
    display: none;
}