*, *:before, *:after {
  box-sizing: border-box;
}

body {
  margin: 40px;
  font-family: 'Open Sans', 'sans-serif';
  background-color: #fff;
  color: #444;
}

h1, p {
  margin: 0 0 1em 0;
}

h2 {
  font-size: 1.3em;
}

h3 {
  font-size: 1.2em;
}

.wrapper {
  max-width: 1400px;
  margin: 0 20px;
  display: grid;
  grid-gap: 10px;
}

.header {
  background-color: aliceblue;
}

@media screen and (min-width: 700px) {

  /* no grid support? */
  .sidebar {
    float: left;
    width: 40%;
    min-width: 350px;
  }

  .content {
    float: right;
    width: 60%;
  }

  .wrapper {
    margin: 0 auto;
    grid-template-columns: 1fr 3fr;
  }
  
  h1, h2 {
    grid-column: 1 / -1;
    /* needed for the floated layout */
    clear: both;
  }

}

@media screen and (min-width: 1000px) {
  .sidebar {
    min-width: 550px;
  }
}

.wrapper div {
  background-color: #c0c0c0;
  border-radius: 5px;
  padding: 20px;
  
  /* needed for the floated layout*/
  margin-bottom: 10px;
}

/* We need to set the widths used on floated items back to auto, and remove the bottom margin as when we have grid we have gaps. */
@supports (display: grid) {
  .wrapper div {
    width: auto;
    margin: 0;
  }
}