index.css

html, body {
  position: relative;
  height: 100%;
}

body {
  font-family: sans-serif;
  font-weight: 300;
  display: flex;
  flex-direction: column;
  max-width: 700px;
  margin: 0 auto;
  text-align: center;
}

#content {
  display: none;
}

#browser-warning-screen {
  display: none;
  position: absolute;
  width: 100%;
  height: 100%;
  z-index: 1000;
  background: white;
}

#browser-warning-msg {
  position: relative;
  top: 50%;
  transform: translateY(-50%);
}

/* header */

#header {
  margin-top: 40px;
}

#header-text {
  font-weight: 300;
  letter-spacing: 2px;
}

#description {
  font-size: 12px;
  margin-bottom: 0;
}

#divider {
  border-bottom: 1px solid black;
  margin: 20px auto;
  width: 10px;
}

/* upload container */

#upload-container {
  margin-bottom: 20px;
}

#upload-header {
  font-weight: 300;
  font-size: 20px;
}

#upload-btn {
  border: 1px solid black;
  width: 113px;
  margin: 0 auto;
  letter-spacing: 2px;
  padding: 5px 0px;
  font-size: 12px;
  cursor: pointer;
  transition: 0.5s;
}

#upload-btn:hover {
  border-color: transparent;
}

#video-file {
  display: none;
}

/* upload params */

#range-inputs {
  margin-bottom: 10px;
}

.range-input-container {
  display: block;
  margin: 0 auto;
  width: 140px;
}

#frame-rate-range-input-container {
  margin-top: 7px;
}

.range-input-label {
  display: block;
  font-size: 12px;
  margin-bottom: 5px;
}

#gif {
  margin-top: 20px;
}

/* progress container */

#progress-container {
  display: none;
  font-size: 12px;
  margin-bottom: 20px;
}

#progress-indicator {
  margin-bottom: 10px;
}

.rotating-smiley {
  display: inline-block;
  margin: auto 10px;
  -webkit-animation:spin 2s linear infinite;
  -moz-animation:spin 2s linear infinite;
  animation:spin 2s linear infinite;
}

@-moz-keyframes spin { 100% { -moz-transform: rotateY(360deg); } }
@-webkit-keyframes spin { 100% { -webkit-transform: rotateY(360deg); } }
@keyframes spin { 100% { -webkit-transform: rotateY(360deg); transform:rotateY(360deg); } }