main.css

html, body {
    margin: 0;
    padding: 0;
    height: 100%;
}

* {
  font-family: Verdana, Geneva, Tahoma, sans-serif;
  font-size: 10pt;
}

.logo {
    z-index: 1;
    position: absolute;
    top: 1em;
    left: 1em;
    width: 150px;
}

.textbox {
    width: 200px;
    z-index: 1;
    position: absolute;
    top: 1em;
    right: 3em;
    background: whitesmoke
}

input#delayLength {
  width: 190px;
}

.currentColor{
  text-align: center
}

.availableColors {
  display:table;
}

.square {
  width: 40px;
  float:left;
  height: 40px;
  background: red;
  border-width: 4px;
  border-color: #000;
  border-style: hidden;
  margin:5px;
  box-sizing:border-box;
}
  
  /* The slider itself */
  .slider {
    -webkit-appearance: none;  /* Override default CSS styles */
    appearance: none;
    width: 98%; /* Full-width */
    height: 25px; /* Specified height */
    background: #d3d3d3; /* Grey background */
    outline: none; /* Remove outline */
    opacity: 0.7; /* Set transparency (for mouse-over effects on hover) */
    -webkit-transition: .2s; /* 0.2 seconds transition on hover */
    transition: opacity .2s;
    
  }
  
  /* Mouse-over effects */
  .slider:hover {
    opacity: 1; /* Fully shown on mouse-over */
  }
  
  .slider::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 25px;
    height: 25px;
    border-radius: 50%; 
    background: #4CAF50;
    cursor: pointer;
  }
  
  .slider::-moz-range-thumb {
    width: 25px;
    height: 25px;
    border-radius: 50%;
    background: #4CAF50;
    cursor: pointer;
  }