Answers for "css fixed height"

css height property

/* <length> values */
height: 300px;
height: 25em;

/* <percentage> value */
height: 75%;

/* Keyword values */
height: max-content;
height: min-content;
height: fit-content(20em);
height: auto;

/* Global values */
height: inherit;
height: initial;
height: unset;

fixed within the div css

#wrapper { width: 300px; background: orange; margin: 0 auto; position: relative; }
#feedback { position: fixed; right: 0; top: 120px; }

<div id="wrapper">
    ...
    <a id="feedback" href="#">Feedback</a>
</div>

how to position fixed inside a div

//Do not forget the absolute position!

.parentDiv{
position: relative;
}

.insideParentDiv{
position: absolute;
}