style.css

/*ESTILOS GENERALES*/

*{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body{
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    height: 100vh;
    text-align: center;
    background: url(images/rm373batch13-086.jpg) ;
    background-attachment: fixed;
    background-position: 0%;
    background-size:cover;
    background-repeat: no-repeat;
}
.contenido-centrado{
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    justify-content: center;
}

.contenedorPrincipal{
    width: 80vw;
    max-width: 600px;
    min-height: 500px;
    padding: 20px;
    background-color: white;
    border: 5px solid black;
    border-radius: 30px;
}

.contenedorInterno{
    width: 80%;
}

/*Contenido*/

#titulo{
    width: 100%;
    font-weight: bold;
    text-align: center;
    font-family: Cambria, Cochin, Georgia, Times, 'Times New Roman', serif;
}

#ecuacion{
    font-size: 32px;
    width: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    margin-bottom: 15%;
    padding-bottom: 15%;
}

#boton{
    width: 180px;
    height: 50px;
    margin: 1%;
    padding: 1%;
}

.contenedorSecundario{
    margin-top: 10%;
    padding-top: 5%;
}
.contenedorSecundario p{
    margin-right: 15px;
}