Sass + autoprefix compiled

compiled.css

.wrapper {
  width: 960px;
  max-width: 100%;
  margin: 0 auto;
}

.wrapper::after {
  clear: both;
  content: "";
  display: block;
}

.form-top {
  width: -webkit-calc(100% - 40px);
  width: calc(100% - 40px);
  float: left;
  margin-left: 20px;
  text-align: center;
}

.column {
  width: -webkit-calc(50% - 30px);
  width: calc(50% - 30px);
  float: left;
  margin-left: 20px;
  padding: 0 1.5rem;
}

@media screen and (max-with: 700px) {
  .column {
    width: -webkit-calc(100% - 40px);
    width: calc(100% - 40px);
    float: left;
    margin-left: 20px;
  }
}

.split {
  margin-left: -20px;
  margin-right: -20px;
  width: -webkit-calc(100% + 40px);
  width: calc(100% + 40px);
}

.split::after {
  clear: both;
  content: "";
  display: block;
}

.split .col-1 {
  width: -webkit-calc(8.33333% - 21.66667px);
  width: calc(8.33333% - 21.66667px);
  float: left;
  margin-left: 20px;
}

.split .col-2 {
  width: -webkit-calc(16.66667% - 23.33333px);
  width: calc(16.66667% - 23.33333px);
  float: left;
  margin-left: 20px;
}

.split .col-3 {
  width: -webkit-calc(25% - 25px);
  width: calc(25% - 25px);
  float: left;
  margin-left: 20px;
}

.split .col-4 {
  width: -webkit-calc(33.33333% - 26.66667px);
  width: calc(33.33333% - 26.66667px);
  float: left;
  margin-left: 20px;
}

.split .col-5 {
  width: -webkit-calc(41.66667% - 28.33333px);
  width: calc(41.66667% - 28.33333px);
  float: left;
  margin-left: 20px;
}

.split .col-6 {
  width: -webkit-calc(50% - 30px);
  width: calc(50% - 30px);
  float: left;
  margin-left: 20px;
}

.split .col-7 {
  width: -webkit-calc(58.33333% - 31.66667px);
  width: calc(58.33333% - 31.66667px);
  float: left;
  margin-left: 20px;
}

.split .col-8 {
  width: -webkit-calc(66.66667% - 33.33333px);
  width: calc(66.66667% - 33.33333px);
  float: left;
  margin-left: 20px;
}

.split .col-9 {
  width: -webkit-calc(75% - 35px);
  width: calc(75% - 35px);
  float: left;
  margin-left: 20px;
}

.split .col-10 {
  width: -webkit-calc(83.33333% - 36.66667px);
  width: calc(83.33333% - 36.66667px);
  float: left;
  margin-left: 20px;
}

.split .col-11 {
  width: -webkit-calc(91.66667% - 38.33333px);
  width: calc(91.66667% - 38.33333px);
  float: left;
  margin-left: 20px;
}

.split .col-12 {
  width: -webkit-calc(100% - 40px);
  width: calc(100% - 40px);
  float: left;
  margin-left: 20px;
}

.split .right {
  float: right;
  margin-right: 20px;
}