body {
  font-family: "Roboto", sans-serif;
  max-width: 1000px;
  margin: 30px auto;
}

h1 {
  text-align: center;
}

textarea {
  width: 100%;
  height: 300px;
  font: 1.2em monospace;
}

#buttons {
  text-align: right;
}

#editor {
  display: flex;
  gap: 8px;
  height: 500px;
}

#files {
  flex: none;
  height: 100%;
}

#input-wrap {
  position: relative;
  flex: 1;
  min-width: 0;
  height: 100%;
}

/* The textarea is transparent and lies over the highlighted pre: both must
   have exactly the same geometry. */
#input, #highlight {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  margin: 0;
  box-sizing: border-box;
  padding: 4px;
  border: 1px solid #aaa;
  font: 1.2em monospace;
  white-space: pre-wrap;
  overflow-wrap: break-word;
  overflow-y: scroll;
}

#highlight {
  pointer-events: none;
  color: black;
  background: white;
}

#input {
  background: transparent;
  color: transparent;
  caret-color: black;
  resize: none;
}

#highlight .comment { color: #888; font-style: italic; }
#highlight .keyword { color: #a020f0; }
#highlight .symbol  { color: #0060c0; }
#highlight .hole    { color: #d00; }