.cell {
    margin: 1em 0;
    border-radius: 0.5em;
    border: 1px solid black;
    padding: 1em;
}
.cell-input {
    width: 100%;
    box-sizing: border-box;
    margin-bottom: 1em;
    padding: 0.6em;
}
.cell-result {
    border-radius: 0.75em;
    background: #eee;
    padding: 0.75em;
}
.cell-input,
.cell-result {
    font-family: sans-serif;
    font-size: 0.9em;
}
body {
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}
.hide {
    display: none;
}
.plot {
    display: block;
}
.plot-err {
    color: red;
    width: 600px;
    height: 480px;
    display: flex;
    flex-direction: column;
    justify-content: center;
}
.plot-err h2 {
    text-align: center;
}