html, body {
  height: 100%;
  margin: 0;
}

body {
  font-family: "Open Sans";
  font-size: 14px;
}

body > .container {
  display: flex;
  flex-flow: column;
  height: 100%;
}

header {
  border-bottom: 1px solid rgba(0, 0, 0, 0.2);
  padding-bottom: 10px;
  margin-bottom: 10px;
}

footer {
  padding-bottom: 10px;
}

body > .container > .row {
  flex: 1 1 auto;
}

.col-md-6 {
  height: 100%;
}

#html-input, #php-output {
  resize: none;
}