auto generated css files?

[Gurpreet]

im seeing css files that are called html.css, forms.css appear on my site when i use firebug.

Does anyone know where these are coming from? and how do i stop them from appearing?

Heres a snippet of some of the css from forms.css:

*|*::-moz-fieldset-content {
display:block;
height:100%;
}
legend {
border:medium none;
float:none !important;
height:auto !important;
max-height:none !important;
max-width:none !important;
min-height:0 !important;
min-width:0 !important;
padding-left:2px;
padding-right:2px;
position:static !important;
white-space:nowrap;
width:-moz-fit-content !important;
}
fieldset {
border:2px groove threedface;
display:block;
margin-left:2px;
margin-right:2px;
padding:0.35em 0.625em 0.75em;
}
label {
cursor:default;
}
input {
-moz-appearance:textfield;
-moz-user-select:text;
-x-system-font:-moz-field;
background-color:-moz-field;
border:2px inset threedface;
color:-moz-fieldtext;
cursor:text;
font-family:-moz-use-system-font;
font-size:-moz-use-system-font;
font-size-adjust:-moz-use-system-font;
font-stretch:-moz-use-system-font;
font-style:-moz-use-system-font;
font-variant:-moz-use-system-font;
font-weight:-moz-use-system-font;
letter-spacing:normal;
line-height:normal !important;
padding:1px 0;
text-align:start;
text-indent:0;
text-rendering:optimizelegibility;
text-transform:none;
word-spacing:normal;
}
input > .anonymous-div {
white-space:pre;
}