main.css

html,
body {
  height: 100%;
}

body {
  background-color: #928dab;
  background-image: -webkit-gradient(linear, left bottom, left top, color-stop(0, #1f1c2c), color-stop(1, #928dab));
  background-image: -moz-linear-gradient(center bottom, #1f1c2c 0%, #928dab 100%);
  background-repeat: no-repeat;
  background-attachment: fixed;
}

html,
body,
#videos iframe {
  margin: 0;
  padding: 0;
}

#videos iframe {
  border: 0;
}

#videos {
  height: 100%;
}

body,
h1,
h2,
h3,
h4,
h5,
h6 {
  font-family: "Open Sans", Helvetica, Verdana, sans-serif;
}

body {
  font-weight: 300;
  color: #727272;
}

h1,
h2,
h3,
h4,
h5,
h6 {
  font-weight: 600;
  font-size: 2.5em;
  color: #534768;
}

#not-video h1 a,
#not-video h1 a:hover,
#not-video h1 a:active,
#not-video h1 a:visited {
  text-decoration: none;
  color: #534768;
}

#not-video h1 {
  margin-top: 0;
}

#not-video {
  padding-left: 1em;
  padding-right: 1em;
  padding-top: 0.75em;
  padding-bottom: 1em;
  background-color: #ffffff;
}

header,
main,
footer {}

main textarea {
  min-width: 50%;
  height: 5em;
  vertical-align: text-top;
}

@keyframes arrow-animation {
  0% {
    background-position: 50% 50%;
  }
  10% {
    background-position: 45% 45%;
  }
  20% {
    background-position: 47% 47%;
  }
  30% {
    background-position: 45% 45%;
  }
  50% {
    background-position: 50% 50%;
  }
  100% {
    background-position: 50% 50%;
  }
}

#videos:empty {
  background-image: url("../image/arrow-north-west.svg");
  background-position: 50% 50%;
  background-size: 25%;
  background-repeat: no-repeat;
  opacity: 0.1;
  animation-name: arrow-animation;
  animation-duration: 9s;
  animation-iteration-count: infinite;
}

#controls button {
  display: block;
}

main textarea,
#controls input {
  background-color: #ffffff;
}

#controls button {}

#controls a {
  float: right;
  margin-top: 0.1em;
  margin-right: 0.5em;
  color: #ffffff;
  font-size: 0.9em;
}

#removeAllUrls {
  display: none;
}

#videos iframe,
#controls input {
  /* TODO: use -prefix-free */
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  /* Opera should not need a prefix, but anyways */
  -o-box-sizing: border-box;
  box-sizing: border-box;
}

.videoPanelsHorizontal-1 iframe,
#controls.urlInputs-1 input {
  width: 100%;
}

.videoPanelsHorizontal-2 iframe,
#controls.urlInputs-2 input {
  width: 50%;
}

.videoPanelsHorizontal-3 iframe,
#controls.urlInputs-3 input {
  width: 33.33333%;
}

.videoPanelsHorizontal-4 iframe,
#controls.urlInputs-4 input {
  width: 25%;
}

.videoPanelsHorizontal-5 iframe,
#controls.urlInputs-5 input {
  width: 20%;
}

.videoPanelsVertical-1 iframe {
  height: 100%;
}

.videoPanelsVertical-2 iframe {
  height: 50%;
}

.videoPanelsVertical-3 iframe {
  height: 33.33333%;
}

.videoPanelsVertical-4 iframe {
  height: 25%;
}

.videoPanelsVertical-5 iframe {
  height: 20%;
}