Google fontlarını offline kulanım için :

https://google-webfonts-helper.herokuapp.com/fonts/roboto?subsets=latin,latin-ext 

/* roboto-regular - latin-ext_latin */
@font-face {
font-family: 'Roboto';
font-style: normal;
font-weight: 400;
src: url('../fonts/roboto-v18-latin-ext_latin-regular.eot'); /* IE9 Compat Modes */
src: local('Roboto'), local('Roboto-Regular'),
url('../fonts/roboto-v18-latin-ext_latin-regular.eot?#iefix') format('embedded-opentype'), /* IE6-IE8 */

       url('../fonts/roboto-v18-latin-ext_latin-regular.woff2') format('woff2'), /* Super Modern Browsers */

       url('../fonts/roboto-v18-latin-ext_latin-regular.woff') format('woff'), /* Modern Browsers */

       url('../fonts/roboto-v18-latin-ext_latin-regular.ttf') format('truetype'), /* Safari, Android, iOS */

       url('../fonts

/roboto-v18-latin-ext_latin-regular.svg#Roboto') format('svg'); /* Legacy iOS */ 

}