6. What units can you use in CSS to specify text size?

You can use various units to specify text size, such as:

• px (pixels): fixed unit, independent of resolution.
• em: relative unit, dependent on the font size of the parent element.
• rem: relative unit, dependent on the font size of the root element (html).
• %: percentage value relative to the parent element.
• vw (viewport width): percentage of the viewport's width.
• vh (viewport height): percentage of the viewport's height.

/* Examples */
h1 {
    font-size: 20px; /* Pixels */
}

h2 {
    font-size: 2em; /* Em - 2 times the font size of the parent element */
}

h3 {
    font-size: 1.5rem; /* Rem - 1.5 times the font size of the root element */
}

h4 {
    font-size: 150%; /* Percentage */
}

h5 {
    font-size: 10vw; /* Viewport width */
}