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

html,
body {
  margin: 0;
  padding: 0;
}

body {
  color: #ddd;
  background-color: #222;
  font-family: sans-serif;
  line-height: 1.5;
  padding: 0 1rem;
}

h1,
h2,
h3,
h4,
h5 {
  font-family: serif;
  font-size: 1.5em;
  line-height: 1.2;
}

header {
  text-align: center;
  padding: 1rem 0;
}

main {
  max-width: 600px;
  margin: 0 auto;
  text-align: center;
}

section.video {
  margin-bottom: 5rem;
}

section.video iframe {
  /* small mobile */
  width: 250px;
  height: 315px;
}

/* for screens 375px & wider (medium mobile) */
@media screen and (min-width: 374px) {
  section.video iframe {
    width: 300px;
    height: 315px;
  }
}

/* for screens 425px & wider (large mobile) */
@media screen and (min-width: 424px) {
  section.video iframe {
    width: 350px;
    height: 315px;
  }
}

/* for screens 768px & wider (tablet, desktop, ultrawide) */
@media screen and (min-width: 767px) {
  section.video iframe {
    width: 560px;
    height: 315px;
  }
}