html,
body {
  margin: 0;
  padding: 0;
  overflow: hidden;
}

#whiteboard {
  width: 100vw;
  height: 100vh;
  display: block;
  background: white;
}

.menu {
  position: fixed;
  top: 0;
  right: 0;
  padding: 0.5rem;
  background-color: whitesmoke;
  font-size: 1.2rem;
}

.clear-button {
  font-size: 1.2rem;
}

.black {
  color: black;
}

.red {
  color: red;
}

.blue {
  color: blue;
}

.footer-links {
  position: fixed;
  bottom: 0.5rem;
  left: 0.5rem;
  font-size: 0.9rem;
  color: #444;
  z-index: 10;
}

.footer-links a {
  color: #adadad;
  text-decoration: none;
  margin-right: 1rem;
}

.footer-links a:hover {
  text-decoration: underline;
}

/* PC */
.pc {
  display: block !important;
}

/* スマホ */
@media only screen and (max-width: 750px) {
  .pc {
    display: none !important;
  }

  .clear-button,
  .menu {
    font-size: 1rem;
  }
}