Adaptive and cross-browser set from the PSD model

On this page is implemented:
The smooth scroll;
the drop-down menu in the mobile version;
the work of sliders;
-lazy loading images(accelerates the download of the site), with keeping the way to the original
a file that allows the possibility of indexing images in the search engines;
prohibition of sending empty form;
verification of the correctness of the email;
If the form is sent successfully or unsuccessfully, the corresponding message appears;