To create lines in CSS, you can use the border property. For example, to create a horizontal line you could use:

.horizontal-line {
  border-top: 1px solid black;
}

To create a vertical line, you can use the border-left property:

.vertical-line {
  border-left: 1px solid black;
}

You can adjust the width, color, and style of the line using different values for the border properties.

Alternatively, you can use the ::before or ::after pseudo-elements with the content property set to an empty string, and then use the border property on the pseudo-element to create lines. For example, to create a horizontal line with the ::before pseudo-element:

.horizontal-line::before {
  content: '';
  display: block;
  border-top: 1px solid black;
}

I hope this helps!