Any modern tutorial for flexbox module?

, flexbox. .

Flexbox .

HTML- ( Codepen ):

<div class="page-wrap">

  <section class="main-content" role="main">
    Main content: first in source order
  </section>

  <nav class="main-nav" role="navigation">
    Links
  </nav>

  <aside class="main-sidebar" role="complementary">
    Sidebar
  </aside>

</div>

page-wrap 3 main-nav , , flexbox. , main-content DOM main-nav, Flexbox . , .

page-wrap a Flexbox. , Flexbox :

.page-wrap {
  display: -webkit-box;      /* OLD - iOS 6-, Safari 3.1-6 */
  display: -moz-box;         /* OLD - Firefox 19- (buggy but mostly works) */
  display: -ms-flexbox;      /* TWEENER - IE 10 */
  display: -webkit-flex;     /* NEW - Chrome */
  display: flex;             /* NEW, Spec - Opera 12.1, Firefox 20+ */
 }

. , . , display -property .

:

.main-content {
  width: 60%;
}
.main-nav,
.main-sidebar {
  -webkit-box-flex: 1;      /* OLD - iOS 6-, Safari 3.1-6 */
  -moz-box-flex: 1;         /* OLD - Firefox 19- */
  width: 20%;               /* For old syntax, otherwise collapses. */
  -webkit-flex: 1;          /* Chrome */
  -ms-flex: 1;              /* IE 10 */
  flex: 1;                  /* NEW, Spec - Opera 12.1, Firefox 20+ */
}

, , , main-nav main-content

.main-content {
  -webkit-box-ordinal-group: 2;   /* OLD - iOS 6-, Safari 3.1-6 */
  -moz-box-ordinal-group: 2;      /* OLD - Firefox 19- */
  -ms-flex-order: 2;              /* TWEENER - IE 10 */
  -webkit-order: 2;               /* NEW - Chrome */
  order: 2;                       /* NEW, Spec - Opera 12.1, Firefox 20+ */
}
.main-nav {
  -webkit-box-ordinal-group: 1;  
  -moz-box-ordinal-group: 1;     
  -ms-flex-order: 1;     
  -webkit-order: 1;  
  order: 1;
}
.main-sidebar {
  -webkit-box-ordinal-group: 3;  
  -moz-box-ordinal-group: 3;     
  -ms-flex-order: 3;     
  -webkit-order: 3;  
  order: 3;
}