css

/* base settings */
* {
  box-sizing: border-box;
}

body {
  margin: 0;
  width: 100%;
  padding: 12px;
}

/* Imaages fit their containers */
img {
  max-width: 100%;
  height: auto;
}

/* Desktop screens */
@media (max-width: 600px) {
  .content {
    width: 100%;
    padding: 12px;
  }
}