*,
*:after,
*::before {
		-webkit-box-sizing: border-box;
		-moz-box-sizing: border-box;
		box-sizing: border-box;
}

body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
    background-color: #f4f4f4;;
    /*background:#fff;*/
    overflow-y: auto;
}

/*form{
  overflow-y: auto;
}*/

header {
    background-color: #333;
    color: #fff;
    padding: 0.15em 0;
    text-align: center;
}

nav ul {
    list-style: none;
    padding: 0;
}

nav ul li {
    display: inline;
    margin: 0 8px;
}

nav ul li a {
    color: #fff;
    text-decoration: underline;
}

h1,h2 {
  text-align: center;
  font-family: "Source Sans Pro", sans-serif;
  font-weight: normal;
}

input[type="range"] {
  /*writing-mode: vertical-lr;*/
  display:flex;
  justify-content: center;
  height: 90px;
}

#slider, #vl{
  display: flex;
  justify-content: center;
}

#description{
  font-size:medium;
  margin:6px 6px;
  padding:9px 9px;
}

#kakoi{
  border: solid #333333;
  border-width: thin medium thick 1em;
}

.double{
     background-color:black;
     color:yellow;
}

/*#description {
  margin:10px;*/
  /*https://developer.mozilla.org/ja/docs/Web/CSS/margin*/
  /*
When 2 values are specified, 
the first margin applies to the top and bottom, 
the second to the left and right.

When 3 values are specified, 
the first margin applies to the top, 
the second to the right and left, 
the third to the bottom.
  */
  /*padding:10px;*/
  /*https://developer.mozilla.org/ja/docs/Web/CSS/padding*/
/*}*/

/*body {*/
  /*background:rgb(159, 210, 90);*/
  /*background:hsla(203, 71%, 77%, 0.878)*/
/*}*/

#value{
  font-size:30px;
}

button[type="submit"]{
  /*color:red;*/
  margin: 10px 50px 20px;
}

footer {
    background-color: #333333;
    color: #fff;
    text-align: center;
    padding: 0.09em 0;
    position: fixed;
    width: 100%;
    bottom: 0;
}