style.css

:root {
  font-size: 16px;
}

body {
  margin: 0;
  font-family: monospace;
  background: #eee;
  color: #111;
}

header {
  width: 100vw;
  text-align: center;
}

.app {
  margin: 0 auto;
  width: 90vw;
  display: flex;
  flex-flow: row nowrap;
  align-items: flex-start;
  justify-content: center;
}

.user-input {
  background: #111;
  color: #eee;
  padding: 1rem 2rem 2rem;
  margin-top: 1rem;
  min-width: 20vw;
}

.output {
  margin: 2rem;
  flex-grow: 1;
  text-align: center;
}

h2 {
  text-align: center;
}

.input__row {
  display: flex;
  flex-flow: row wrap;
  justify-content: flex-start;
  align-items: flex-start;
  margin-bottom: 1rem;
}

.input__unit {
  font-size: .6em;
}

.input__row input {
  margin-left: 0.5rem;
}

#text-input {
  flex-grow: 1;
}

.text-area, .svg-area {
  margin-bottom: 2rem;
}

h3 {
  text-align: left;
}

.text-target {
  display: block;
  font-size: 0.8rem;
  box-sizing: border-box;
  padding: 1rem;
  border: 1px solid black;
  text-align: left;
}