style.css

html {
    box-sizing: border-box;
    font-size: 62.5%;
    /**reset para rems 62.5%=10 px de 16px*/
}

*,
*:before,
*:after {
    box-sizing: inherit;
}

body {
    font-family: 'Lato', sans-serif;
    font-size: 1.6rem;
    line-height: 2;
    background-color: #e9e49d;
}

.centrar {
    text-align: center;
}

.formulario {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.main {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.boton {
    color: white;
    background-color: #71B100;
    font-weight: 700;
    text-decoration: none;
    font-size: 1.8rem;
    padding: 1rem 3rem;
    text-align: center;
    border: none;
    flex: 0 0 100%;
    cursor: pointer;
    border-radius: .8rem;
}

.etiqueta {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.area {
    background-color: #e7e4b3;
    max-width: 80%;
    resize: none;
}

.res {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 1rem;
}

.resultado {
    padding: .6rem 0;
}

.imagen {
    background-color: black;
    padding: 1rem;
}

.creditos {
    margin-top: 5rem;
    display: flex;
    flex-direction: column;
    align-items: center;
}