<'vertical-align'> = baseline | sub | super | top | text-top | middle | bottom | text-bottom | <percentage> | <length> | inherit
baseline
Align the baseline of the box with the baseline of the parent box. If the box does not have a baseline, align the bottom margin edge with the parent's baseline.
sub
Lower the baseline of the box to the proper position for subscripts of the parent's box.
super
Raise the baseline of the box to the proper position for superscripts of the parent's box.
top
Align the top of the aligned subtree with the top of the line box.
text-top
Align the top of the box with the top of the parent's content area.
middle
Align the vertical midpoint of the box with the baseline of the parent box plus half the x-height of the parent.
bottom
Align the bottom of the aligned subtree with the bottom of the line box.
text-bottom
Align the bottom of the box with the bottom of the parent's content area.
<percentage>
Specifies the percentage using a number followed by a percent sign (%).
<length>
Specifies the length using a number followed by a unit of measurement.