.letter-style {
    padding: 7%;
    align-items: center;
}
.precios {
    list-style: none;
    padding: 0;
    font-size: 1.4rem;
}
.precios li {
    display: flex;
    justify-content: space-between;
    padding: 10px 0;
    border-bottom: 10px solid #ebe9e9; /* opcional */
}
.costos-img {
    text-align: center;
    margin-top: 5%;
}
.costos-img img {
    display: inline-block;
    width: 60%;
    border: 15px solid black;
}