styles.css

/*  fonts */
@import url('https://fonts.googleapis.com/css?family=Roboto');

body,
.book.font-family-1 {
  font-family: "Roboto", Helvetica, Arial, sans-serif;
}

/* link colour */
.book .book-summary ul.summary li a:hover, .book .book-summary ul.summary li.active>a,
.book .book-body .page-wrapper .page-inner section.normal a:link {
    color: #0074d9;
}
.book .book-body .page-wrapper .page-inner section.normal a:visited {
  color: #b10dc9;
}

/*  exercise boxes */
.exercise {
  background-color: #bbf7f5 !important;
}

.exercise h2 {
    padding-left: 25px;
}

/* tip and warning boxes */
.note, .warning {
  padding: 1em 1em 1em 6em;
  background: #dededd 1em center/4em no-repeat;
  border-radius: 2px;
}

.note {
  background-image: url("images/note.png");
}

.warning {
  background-image: url("images/warning.png");
}

/* code boxes */
pre {
    border-radius: 3px;
}