How can I make the login screen effect with the background like iCloud when does the browser size change?
If you repair the obfuscated objects change position depending on the size of the browser. In the first image are 2 rows of objects by 7 columns, in the second image are 3 rows by 5 columns.
Can you do this with bootstrap?
Browsing the web I found a possible solution for blur appearance, if necessary, what you can understand is everything done by CSS, just a JS to trigger the effect when needed, there is not much secret.
.blur {
-webkit-filter: blur(5px);
-moz-filter: blur(5px);
-o-filter: blur(5px);
-ms-filter: blur(5px);
filter: blur(5px);
}
Follow link to effect instructions: link
In the matter of replacing objects, objects reposition themselves, a similar effect is the bootstrap grid-system / thumbnails >.