Style The Twenty Seventeen Theme Title and Tagline

Depending on your background image colors, title and tagline may be not so clearly seen. Here are CSS tips to improve visibility…

For the title in a first time:

.site-title {
  font-family: 'Ubuntu'; /* the font you want for tagline text */
  background-color: #000000; /* the color you want for title background */
  padding-left: 10px !important;
}
.site-title a {
  color:#fff !important; /* the color you want for title text */
}

And for the tagline too:

.site-description {
  font-family: 'Ubuntu'; /* the font you want for tagline text */
  font-weight: bold;
  font-size: 20px;
  opacity: 1 !important;
  background-color: #000000; /* the color you want for tagline background */
  padding: 1rem .5rem 1rem .5rem;
}
.site-description{
  color:#fff !important; /* the color you want for tagline text */
}

Just copy those code snippets and paste them in the Additionnal CSS of WordPress Customizer, and enjoy!