article {width: 46%;} left-sidebar {width: 25%;} right-sidebar {width: 25%;} /* 100% - 46% - 25% * 2 = 4% */ /* ОШИБКА */ article {margin-rigth: 2%;} left-sidebar {margin-rigth: 2%;}
.article-wrp {width: calc(46% + 2%);}
/* 48% - 100%
2% - x
x = 2 * 100 / 48 = 4,166
*/
.article {width: calc(100% - 4,16%);}
Пример расчета inline-block