/* Part B - Flexbox. IMPORTANT: HTML classes are identical to the plain version. */
html, body { height: 100%; }
* { box-sizing: border-box; margin: 0; padding: 5px; }

.page {
  height: 100%;
  display: flex;
}

/* Remove float behavior for flex version */
[class*="col-"] {
  border: 1px solid red;
  float: none;
}

/* Column widths as flex-basis */
.col-1  { flex: 0 0 8.33%; }
.col-2  { flex: 0 0 16.66%; }
.col-3  { flex: 0 0 25%; }
.col-4  { flex: 0 0 33.33%; }
.col-5  { flex: 0 0 41.66%; }
.col-6  { flex: 0 0 50%; }
.col-7  { flex: 0 0 58.33%; }
.col-8  { flex: 0 0 66.66%; }
.col-9  { flex: 0 0 75%; }
.col-10 { flex: 0 0 83.33%; }
.col-11 { flex: 0 0 91.66%; }
.col-12 { flex: 0 0 100%; }

/* Left/right full height */
.leftSide, .rightSide { height: 100%; }

/* Right side wraps items into rows */
.rightSide {
  display: flex;
  flex-wrap: wrap;
  align-content: flex-start;
}

/* Heights for items (percent of rightSide height) */
.smallCol { height: 20%; }
.biglCol  { height: 40%; }

/* The split big column should stack two halves */
.biglCol--split {
  display: flex;
  flex-direction: column;
}

.halfCol { flex: 1 1 auto; }

/* Mobile: stack everything */
@media (max-width: 750px) {
  .page { flex-direction: column; height: auto; min-height: 100vh; }
  [class*="col-"] { flex: 0 0 100%; width: 100%; }
  .leftSide, .rightSide { height: auto; }
  .smallCol, .biglCol { height: auto; min-height: 90px; }
}