My line height will not adjust

I am trying to adjust my line height to get the text closer together. https://astra.uta.edu/ There is too much spacing between lines in all of my pages. This is my current css:

textarea {
color: #333;
font-family: “Helvetica Neue”, “Helvetica Neue”, Calibri, Arial, “Lucida Grande”, sans-serif;
font-size: 15px;
line-height: 1.5em;
}

I figured out how to change the text size but the height I have changed to several things…1; 15px; 100%; normal; but nothing has worked. Even if I have to add individual html to each page I will but someone please help me with some insight.