body {
   padding: 1em;
   div.test {
      border: 1px solid grey;
      padding: 1em;
      margin: 0 2em 1em;
   }
}

div#t1 {
   table,
   td, 
   th {
      border: 1px solid lightgrey;
      padding: 0.5em;
      border-collapse: collapse;
   }
}

div#t2 {
   div.table {
      display: flex;
      flex-direction: column;
   }
   div.row {
      display: flex;
      min-height: 50px;
   }
   div.cell {
      flex: 4;
      border: 1px solid lightgrey;
   }
   div.cell:nth-child(1) {
      flex: 1;
   }
   div.cell:nth-child(2) {
      flex: 2;
   }
   div.cell.span4-5 {
      flex: 8 24px;                    /*  col 4,5 flex-grow/border/padding  */
   }
   div.cell.span3-4 {
      flex: 8 24px;                    /*  col 3,4 flex-grow/border/padding  */
   }
   div.cell.span3-5 {
      flex: 12 36px;                   /*  col 3,4,5 flex-grow/border/padding  */
   }
   div.row:first-child div.cell {
      display: flex;
      justify-content: center;         /*  center horiz. */
      align-items: center;             /*  center vert. */
      font-weight: bold;
   }
   div.row div.cell {
      padding: 5px;
      box-sizing: border-box;
   }
}

div#t3 {
   .container {
      display: flex;
      flex-wrap: wrap;                    /*  allow items to wrap  */
      justify-content: space-between;     /*  vertical  */
      align-items: stretch;               /*  horizontal, is default and can be omitted  */
   }
   .item {
      flex-basis: 25%;                    /*  give each item a width  */
      border: 1px solid lightgrey;
      box-sizing: border-box;
      flex-shrink: 0;                     /*  prevent from "shrink to fit" */
      min-width: 0;                       /*  allow to shrink past content width  */
      overflow: hidden;                   /*  hide overflowed content  */
   }
   .item:nth-child(n+5) {
      margin-top: 10px;                   /*  from 5th item, add top margin  */
   }
}

div#t4 {
   /* (A1) CONTAINER - BIG SCREEN */
   .thegrid {
     display: grid;
     grid-template-columns: auto auto auto auto;
     /* OR SPECIFY WIDTH
     */
     grid-template-columns: 40% 20% 20% 20%;
     grid-gap: 5px;
   }
   /* (A2) CONTAINER - SMOL SCREEN */
   @media screen and (max-width:768px) {
     .thegrid { grid-template-columns: auto auto; }
   }
   /* (B) CELLS */
   .thegrid .head, .thegrid .cell {
     padding: 10px;
   }
   /* (C) HEADER CELLS */
   .thegrid .head {
     font-weight: bold;
     background: #ffe4d1;
   }
   /* (D) DATA CELLS */
   .thegrid .cell {
     background: #d1f2ff;
   }
}