1.   nav                                      { color: purple; }    /* 0-0-1  =    1 */
2.   nav.main-nav                             { color: blue; }      /* 0-1-1  =   11 */
3.   header nav                               { color: lime; }      /* 0-0-2  =    2 */
4.   #navigation nav                          { color: green; }     /* 1-0-1  =  101 */
5.   header#navigation nav                    { color: aqua; }      /* 1-0-2  =  102 */
6.   .home #navigation nav.main-nav           { color: red; }       /* 1-2-1  =  121 */
7.   body.home header.branding nav.main-nav   { color: deeppink; }  /* 0-3-3  =   33 */ 

As we can see, the .home #navigation nav.main-nav selector wins, because it is the most specific. The text color in the nav will be purple.

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