Three Column Layout

by asdf

HTML

<div class="colmask mask1">
  <div class="colmask mask2">
    <div class="colmask mask3">
      <div class="col col1">
    Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book.
      </div>
      <div class="col col2">
    Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.
      </div>
      <div class="col col3">
    Lorem Ipsum is simply dummy text of the printing and typesetting industry.
      </div>
    </div>
  </div>
</div>

<div class="wrapper2">
  <div class="col2 col12">
    Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book.
  </div>
  <div class="col2 col22">
    Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop...

CSS

.colmask {
  width: 100%;
  position: relative;
  float: left;
}
.mask1 {
  background-color: lightgreen;
  overflow: hidden;
}
.mask2 {
  background-color: lightyellow;
  right: calc(100%/3);
}
.mask3 {
  background-color: lightblue;
  right: calc(100%/3);
}
.col {
  width: calc(100%/3);
  float: left;
  position: relative;
  left: calc(2*100%/3);
}
// ==============================
.wrapper2 {
  display: table;
  margin-top: 10px;
}
.col2 {
  width: calc(100%/3);
  display: table-cell;
}
.col12 {
  background-color: blue;
}
.col22 {
  background-color: yellow;
}
.col32 {
  background-color: green;
}
// ==============================
.wrapper3 {
  margin-top: 10px;
}
.col3 {
  width: calc(100%/3);
  display: inline-block;
  vertical-align: top;
}
.col13 {
  background-color: lightblue;
}
.col23 {
  background-color: lightyellow;
}
.col33 {
  background-color: lightgreen;
}