footer.css

.reveal .slide-logo {
  display: block;
  position: fixed;
  bottom: 0;
  right: 12px;
  max-height: 2.2rem;
  height: 100%;
  width: auto;
  z-index: 2;
}

.reveal .footer {
  display: block;
  position: fixed;
  bottom: 18px;
  width: 100%;
  margin: 0 auto;
  text-align: center;
  font-size: 18px;
  z-index: 2;
}

.reveal .footer > * {
  margin-top: 0;
  margin-bottom: 0;
}

.reveal .slide .footer {
  display: none;
}

.reveal .slide-number {
  bottom: 10px;
  right: 10px;
  font-size: 16px;
  background-color: transparent;
}

.reveal.has-logo .slide-number {
  bottom: initial;
  top: 8px;
  right: 8px;
}

.reveal .slide-number .slide-number-delimiter {
  margin: 0;
}

.reveal .slide-menu-button {
  left: 8px;
  bottom: 8px;
}

.reveal .slide-chalkboard-buttons {
  position: fixed;
  left: 12px;
  bottom: 8px;
  z-index: 30;
  font-size: 24px;
}

.reveal .slide-chalkboard-buttons.slide-menu-offset {
  left: 54px;
}

.reveal .slide-chalkboard-buttons > span {
  margin-right: 14px;
  cursor: pointer;
}

@media screen and (max-width: 800px) {
  .reveal .slide-logo {
    max-height: 1.1rem;
    bottom: -2px;
    right: 10px;
  }
  .reveal .footer {
    font-size: 14px;
    bottom: 12px;
  }
  .reveal .slide-number {
    font-size: 12px;
    bottom: 7px;
  }
  .reveal .slide-menu-button .fas::before {
    height: 1.3rem;
    width: 1.3rem;
    vertical-align: -0.125em;
    background-size: 1.3rem 1.3rem;
  }

  .reveal .slide-chalkboard-buttons .fas::before {
    height: 0.95rem;
    width: 0.95rem;
    background-size: 0.95rem 0.95rem;
    vertical-align: -0em;
  }

  .reveal .slide-chalkboard-buttons.slide-menu-offset {
    left: 36px;
  }
  .reveal .slide-chalkboard-buttons > span {
    margin-right: 9px;
  }
}

html.print-pdf .reveal .slide-menu-button,
html.print-pdf .reveal .slide-chalkboard-buttons {
  display: none;
}