Text decorations are drawn across descendant text elements. This means that if an element specifies a text decoration, then a child element can't remove the decoration. For example, in the markup <p>This text has <em>some emphasized words</em> in it.</p>, the style rule p { text-decoration: underline; } would cause the entire paragraph to be underlined. The style rule em { text-decoration: none; } would not cause any change; the entire paragraph would still be underlined. However, the rule em { text-decoration: overline; } would cause a second decoration to appear on "some emphasized words".

This property is a shorthand for the following CSS properties:

• text-decoration-color
• text-decoration-line
• text-decoration-style
• text-decoration-thickness

text-decoration: underline;
text-decoration: overline red;
text-decoration: none;

/* Global values */
text-decoration: inherit;
text-decoration: initial;
text-decoration: revert;
text-decoration: revert-layer;
text-decoration: unset;

The text-decoration property is specified as one or more space-separated values representing the various longhand text-decoration properties.

text-decoration-line

Sets the kind of decoration used, such as underline or line-through.

text-decoration-color

Sets the color of the decoration.

text-decoration-style

Sets the style of the line used for the decoration, such as solid, wavy, or dashed.

text-decoration-thickness

Sets the thickness of the line used for the decoration.

text-decoration = 
  <'text-decoration-line'>   ||
  <'text-decoration-style'>  ||
  <'text-decoration-color'>  

.under {
  text-decoration: underline red;
}

.over {
  text-decoration: wavy overline lime;
}

.line {
  text-decoration: line-through;
}

.plain {
  text-decoration: none;
}

.underover {
  text-decoration: dashed underline overline;
}

.thick {
  text-decoration: solid underline purple 4px;
}

.blink {
  text-decoration: blink;
}

<p class="under">This text has a line underneath it.</p>
<p class="over">This text has a line over it.</p>
<p class="line">This text has a line going through it.</p>
<p>
  This <a class="plain" href="#">link will not be underlined</a>, as links
  generally are by default. Be careful when removing the text decoration on
  anchors since users often depend on the underline to denote hyperlinks.
</p>
<p class="underover">This text has lines above <em>and</em> below it.</p>
<p class="thick">
  This text has a really thick purple underline in supporting browsers.
</p>
<p class="blink">
  This text might blink for you, depending on the browser you use.
</p>

Result

• The individual text-decoration properties are text-decoration-line, text-decoration-color, text-decoration-style, and text-decoration-thickness.
• The text-decoration-skip-ink, text-underline-offset, and text-underline-position properties also affect text-decoration, but are not included in the shorthand.
• The list-style attribute controls the appearance of items in HTML <ol> and <ul> lists.