html {
  height: 100%;
}

body {
  height: 100%;
  display: flex;
  flex-direction: column;
  margin: 0px;
}

.viewport {
  display: flex;
  flex: 1;
  flex-direction: column;
}

.details {
  height: 100%;
  flex: 1;
}

div.page {
  width: 100%;
  height: 100%;
  display: flex;
  justify-content: center;
}

textarea.text {
  padding: 15px;
  line-height: 1.75em;
  border: none;
  width: 100%;
  flex: 1;
  font-family: arial;
  font-size: 1.2em;
  overflow-y: scroll;
  overflow-x: hidden;
  resize: none;
}

.tools,
.controls {
  width: 100%;
  background-color: #000;
  color: #fff;
  text-align: center;
}

.tools {
  padding: 8px 4px 2px 4px;
}

.controls {
  padding: 2px 4px 8px 4px;
}

.controls select {
  margin: 1px;
}

.tools button {
  font-size: 1.0em;
  padding: 7px;
  margin: 4px;
  border: none;
  background-color: darkorange;
  color: #fff;
  border-radius: 5px;
}

.tools button:hover {
    background-color: chocolate;
}

.tools button.switch {
  width: 74px;
}

.tools button.books {
  position: absolute; left: 0;
  margin-left: 7px;
}

.tools button.about {
  position: absolute; right: 0; 
  margin-right: 7px;
}

.tools button:disabled {
  background: #ccc;
}