Das machst du in der css/main.css

HTML-Code:
textarea {
border-width: 1;
font-size: 12px;
font-family: Geneva, Arial, Helvetica, san-serif;
border-color: #000000;
border-style: solid;
background-color: #A2B5CD;
color: #000000;
font-weight: normal;
}
Zeile 3
font-size: 12px