How To Create a Three Column Layout

HTML

<div class="row">

  <div class="column"></div>
  <div class="column"></div>
  <div class="column"></div>
</div>

CSS

.column {
  float: left;
  width: 33.33%;
}

/* Clear floats after the columns */
.row:after {
  content: "";
  display: table;
  clear: both;
}

EXAMPLE CSS FOR UNEQUAL COLUMN

.column {
  float: left;
}

.left, .right {
  width: 25%;
}

.middle {
  width: 50%;
}

Responsive three column layout: CSS

/* Responsive layout - when the screen is less than 600px wide, make the three columns stack on top of each other instead of next to each other */
@media screen and (max-width: 600px) {
  .column {
    width: 100%;
  }
}