* {
  box-sizing: border-box;
}

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

body {
  padding: 50px;
  font-family: 'Roboto', sans-serif;
  color: #555;
}

#column {
  display: flex;
  flex-direction: column;
  height: 100%;
}

textarea {
  width: 100%;
  font-family: inherit;
  font-size: 1.2em;
  color: #555;
  flex-grow: 1;
  border: 2px solid #DDD;
  outline: none;
  padding: 10px;
  background-color: #FAFAFA;
  margin-bottom: 30px;
}

#letters,
#numbers,
#keys {
  display: flex;
}

.letter,
.number {
  font-size: 2em;
  flex-grow: 1;
  flex-basis: 100%;
  text-align: center;
  height: 50px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  cursor: pointer;
}

.letter.hover,
.number.hover {
  background: #AEF;
}

.number {
  font-size: 1.3em;
}

#keys {
  justify-content: center;
  margin-top: 30px;
}

.key {
  padding: 15px;
  font-size: 2em;
  border: 2px solid #DDD;
  border-radius: 8px;
  margin-right: 20px;
  min-width: 75px;
  text-align: center;
}

.key.resting {
  background: repeating-linear-gradient(
    45deg,
    #EEE,
    #EEE 2px,
    #FAFAFA 2px,
    #FAFAFA 4px
  );
}

.key.hover {
  background: #AEF;
}

.key #label {
  margin-left: 5px;
  font-size: 0.4em;
}