Typography Basics and Text-Align

Font family

font-family determines what font an element uses.
If a browser cannot find or does not support the first font in a list, it will use the next one, then the next one and so on until it finds a supported and valid font.

font-family: "DejaVu Sans", sans-serif;

Font family name: like "DejaVu Sans" (we use quotes due to the whitespace between words).
Generic family name: like sans-serif (generic family names never use quotes).

font-weight affects the boldness of text, assuming the font supports the specified weight.

font-weight: bold
font-weight: 700 /* (a number between 1 and 1000) */

text-align: center

img {
  height: auto;
  width: 500px;
}

To adjust the size of the image without losing its proportions, you can use “auto” for the height property and adjust the width value.
It’s best to include both of these properties even if you don’t plan on adjusting the values from the image file’s original ones.
When these values aren’t included, if an image takes longer to load than the rest of the page contents, the image won’t take up any space on the page at first, but will suddenly cause a drastic shift of the other page contents once it does load in. Explicitly stating a height and width prevents this from happening, as space will be “reserved” on the page and will just appear as a blank space until the image loads.