#button1:focus~#content #def,
#button2:focus~#content #def,
#button3:focus~#content #def,
#button4:focus~#content #def,
#button5:focus~#content #def,
#button6:focus~#content #def        {display:none;}

#button1:focus~#content div:nth-child(2),
#button2:focus~#content div:nth-child(3),
#button3:focus~#content div:nth-child(4),
#button4:focus~#content div:nth-child(5),
#button5:focus~#content div:nth-child(6)   {display:block;}

#content {
    border:0px dashed black;
    width:93%; 
    top:0px;
    background:rgba(0,0,0,0);
    color:black;
    font-size:10px;
    text-align:center;
 }



#HMS_Furious_1916,#HMS_Furious_1917,#HMS_Furious_1918,#HMS_Furious_1920s,#HMS_Furious_1940s {display:none;}

<!-- NOTE: DIV NAMES CAN'T START WITH A DIGIT ************************************************************************* -->