.cabezera-texto {
    border-top: 1px solid black;
    border-bottom: 1px solid black;
    text-align: center;
    margin: 100px,0;
    padding: 40px;
    font-size: 3vh;
/* ajusta la cabezera */
}
main img {
    width: 20vw;
    flex-basis: 30%;
}
.curso1 {
    display: flex;
    flex-direction: row;
    justify-content: center;
    align-content: space-around;
    align-items: center;
}
.curso1 .curso1-texto {
    flex-basis: 50%;
    margin-left: 50px;
}
.curso2 {
    display: flex;
    flex-direction: row;
    justify-content: center;
    align-content: space-around;
    align-items: center;
}
.curso2 .curso2-texto {
    flex-basis: 50%;
    margin-right: 50px;

}
.leer-mas {
    border: 5px solid rgb(0, 0, 0);
    border-radius: 60px;
    color: white;
    background-color: rgb(0, 0, 0);
    width: 10rem;
    height: 100%;
    margin-left: auto;
    text-align: center;
}
.leer-mas:hover {
    border: 5px solid rgb(255, 230, 0);
    background-color: rgb(255, 230, 0);
    color: black;
 }