Your style.css file has the text color set for the whole site to a color close to white. On line 60 you have:
body {
font-family: 'Orbitron',sans-serif;
font-size: 13px;
line-height: 24px;
color: #fefefe;
font-weight: 400;
letter-spacing: 0.06em;
background-color: #000;
overflow-y: scroll;
overflow-x: hidden!important;
-webkit-font-smoothing: antialiased;
}
You could add a class to override that setting for input form elements below it like:
input {
color: black;
}