File: examples/assets/custom.css

.hero img {
    width: 100%;
    height: auto;
}
.section {
    text-align: center;
    width: 100%;
    height: 100%;
}
.hero {
    margin-top: 15%;
}
.hero-heading {
    padding-top: 15%;
}
.feedback {
    color: red !important;
}

/* Bigger than 550 */

@media (min-width: 550px) {
    .hero-heading {
        font-size: 2.4rem;
    }
}

/* Bigger than 750 */

@media (min-width: 750px) {
    .hero-heading {
        font-size: 2.5rem;
    }
}

/* Bigger than 1000 */

@media (min-width: 1000px) {
    .hero-heading {
        font-size: 2.6rem;
    }
}