Text

Text utilities to easily change line height, font size, letter spacing, and color of your text.
Bootstrap documentation

Font size

• .font-size-{lg|base|sm|xs|xxs|xxxs} - changes the font size to a specified value.
• .font-size-{h1|h2|h3|h4|h5|h6} - changes the font size to a specified value. Different from the corresponding .h{1-6} utilities because it preserves the default line height and doesn't add additonal margins.

Letter spacing

• .letter-spacing-{lg}|xl} - changes the letter spacing to a specified value.

Color

• .text-gray-{300|350|400|450|500} - changes the text color to a specified gray color. Also changes the hover color if used with links.

Decoration

• .text-decoration-underline - sets the text decoration property to underline. Removes it on hover for links.
• .text-decoration-line-through - sets the text decoration property to line-through.

Style

• .font-style-normal - changes the font style back to normal.

Line height

• .line-height-base - changes the line height to the default value.
• .line-height-fixed - changes the default line height to a fixed value (instead of being specified relatively to the font size).