3 steps:
Ex:
@font-face {_x000D_
font-family: 'Open Sans';_x000D_
font-style: italic;_x000D_
font-weight: 400;_x000D_
src: local('Open Sans Italic'), local('OpenSans-Italic'), url(http://fonts.gstatic.com/s/opensans/v14/xjAJXh38I15wypJXxuGMBvZraR2Tg8w2lzm7kLNL0-w.woff2) format('woff2');_x000D_
unicode-range: U+0460-052F, U+20B4, U+2DE0-2DFF, U+A640-A69F;_x000D_
}
_x000D_
Look at src: -> url. Download http://fonts.gstatic.com/s/opensans/v14/xjAJXh38I15wypJXxuGMBvZraR2Tg8w2lzm7kLNL0-w.woff2 and save to fonts directory. After that change url to all your downloaded file. Now it will be look like
@font-face {_x000D_
font-family: 'Open Sans';_x000D_
font-style: italic;_x000D_
font-weight: 400;_x000D_
src: local('Open Sans Italic'), local('OpenSans-Italic'), url(fonts/xjAJXh38I15wypJXxuGMBvZraR2Tg8w2lzm7kLNL0-w.woff2) format('woff2');_x000D_
unicode-range: U+0460-052F, U+20B4, U+2DE0-2DFF, U+A640-A69F;_x000D_
}
_x000D_
** Download all fonts contain .css file Hope it will help u