Fonts look different on Firefox and IE than on Chrome - css

Question

I am using three fonts that I load via #font-face and they all look like they are supposed to on Chrome, but on Firefox and IE they look different. Like with extra bold added to them and they are more blocky.
#font-face {
font-family: 'OpenSans-Regular';
src: url('../fonts/OpenSans-Regular-webfont.woff') format('woff');
font-weight: normal;
font-style: normal;
}
#font-face {
font-family: 'Montserrat-Regular';
src: url('../fonts/montserrat-regular-webfont.woff2') format('woff2'),
url('../fonts/montserrat-regular-webfont.woff') format('woff');
font-weight: normal;
font-style: normal;
}
#font-face {
font-family: 'Roboto-Regular';
src: url('../fonts/roboto-regular-webfont.woff2') format('woff2'),
url('../fonts/roboto-regular-webfont.woff') format('woff');
font-weight: normal;
font-style: normal;
}
How I apply these fonts to elements:
...
font-family: "OpenSans-Regular", sans-serif;
...
If I edit the element in Firefox with dev tools and set font-family: Open Sans then it works like it should.
This problem is giving me a headache as I don't understand why this is happening.

Answer 1

All applications are developed with specific blocks of code. This is like "Default Font" on HTML and CSS. It happens with all web pages that are opened on different browsers. Try this thing with
Facebook
and you will see the difference between fonts on Chrome and Firefox. If font looked bolder than you wanted it, just play with "font-weight" on CSS StyleSheet. e.g.:
body.font-weight: xx px;

Answer 2

late reply but here goes; Firefox renders headers and some other elements as "double bold" in your case so you would have to remove the font weight from the element in order to normalize this if you don't want to load more font files[1].
To improve the rendering, try loading the fonts as follows[2][3]:
#font-face {
font-family: 'Roboto';
src: url('../fonts/roboto-regular-webfont.woff2') format('woff2'),
url('../fonts/roboto-regular-webfont.woff') format('woff');
font-weight: 400;
font-style: normal;
}
#font-face {
font-family: 'Roboto';
src: url('../fonts/roboto-bold-webfont.woff2') format('woff2'),
url('../fonts/roboto-bold-webfont.woff') format('woff');
font-weight: 700;
font-style: normal;
}
#font-face {
font-family: 'Roboto';
src: url('../fonts/roboto-italic-webfont.woff2') format('woff2'),
url('../fonts/roboto-italic-webfont.woff') format('woff');
font-weight: 400;
font-style: italic;
}
[1] It is better to have fewer fonts but include the correct ones
[2] just the Roboto as an example but the same would apply for the rest as well
[3] consider defining the values in absolute numbers rather than relative values as these can be interpreted differently by the different browsers

Answer 3

Answer to my question was having different font weights, e.g. if you have google fonts then make sure you have light(300), regular (400), medium (500), bold (700) versions imported.