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CSS

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CSS Base

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HTML 

              
                <!-- <a id="academo-banner" href="https://academo.org/demos/wavelength-to-colour-relationship/" target="_blank">Find out more at Academo.org</a> -->

<!-- CSS was online here :  -->
<!--
https://academo.org/scss/main.css?v=1618715105338 -->

<!-- https://academo.org/demos/wavelength-to-colour-relationship/ -->
<!-- <br> -->
  <div style="position:realtive; padding:20px;display:flex;margin-top:0;   justify-content: center">
    <div style="position:realtive; ;display:flex column   ">

      <h1 style="top:0; margin:0 0 10px;border-left:8px solid red; padding-left:10px">Wavelength to Color</h1>

      <p style="font-size:12px;width:700px">
        Over the course of millions of years, the human eye has evolved to detect light in the range 380—780nm;  a portion of the electromagnetic spectrum known as "visible light", which we perceive as colour. The particular range of wavelengths comes in phase with a window in the Earth's atmosphere, through which this light can travel.  Higher frequency radiation, such as X-rays are absorbed by our atmosphere, as are lower wave frequencies, such as microwaves.
        <br>
        Sunlight appears white to us because it emits almost uniformly over all visible wavelength. However, a laser emits only at a single very specific, unique and precise wavelength. We can begin to wrap our mind around how frequency or light wavelength is related to colour.
        <br>
        <br>
        Most of the times, when referring to colour on computer screens is by using the RGB system. In this Red, GRen adn Blue color model, each colour is given a value for each of the 3 components (red, green and blues) ranging from 0 to 255. Hence giving us a total value of 256 x 256 x 256 = 16.7 million possible colours. <br>
        <br>However, due to the very complex way in which our human eyes perceives colors, we can see colors which are <em>outside</em> of the gamut (limit boudaries) of the RGB color space, there is no unique mapping that definitively converts a wavelength to a colour, and as such the below tool should been seen as more of an approximation than a rigorous resource.
    </div>
  </div>

<div style="display:flex;justify-content: center;">
  <div style="display:flex row;margin:10px">
    <div id="demo">
    </div>
    <div id="ui-container">
    </div>
    <div class="pointRepere" id="refPoint"></div>
  </div>


</div>
!

CSS 

              
                @import "https://fonts.googleapis.com/css2?family=Open+Sans:ital,[email protected],400;0,700;1,400&display=swap";
.clearfix:after {
  content: "";
  display: table;
  clear: both;
}
.mobile-show {
  display: none;
}
@media (max-width: 400px) {
  .mobile-show {
    display: block;
  }
  .mobile-hide {
    display: none;
  }
}
@font-face {
  font-family: fontello;
  src: url(/fonts/fontello/fontello.eot?76394341);
  src: url(/fonts/fontello/fontello.eot?76394341#iefix)
      format("embedded-opentype"),
    url(/fonts/fontello/fontello.woff2?76394341) format("woff2"),
    url(/fonts/fontello/fontello.woff?76394341) format("woff"),
    url(/fonts/fontello/fontello.ttf?76394341) format("truetype"),
    url(/fonts/fontello/fontello.svg?76394341#fontello) format("svg");
  font-weight: 400;
  font-style: normal;
}
[class^="icon-"]:before,
[class*=" icon-"]:before {
  font-family: fontello;
  font-style: normal;
  font-weight: 400;
  speak: never;
  display: inline-block;
  text-decoration: inherit;
  width: 1em;
  margin-right: 0.2em;
  text-align: center;
  font-variant: normal;
  text-transform: none;
  line-height: 1em;
  margin-left: 0.2em;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}
.icon-link-ext:before {
  content: "\f08e";
}
.icon-twitter:before {
  content: "\f099";
}
.icon-facebook:before {
  content: "\f308";
} /*!normalize.css v3.0.3 | MIT License | github.com/necolas/normalize.css*/
html {
  font-family: sans-serif;
  -ms-text-size-adjust: 100%;
  -webkit-text-size-adjust: 100%;
}
body {
  margin: 0;
  user-select:none;
}
article,
aside,
details,
figcaption,
figure,
footer,
header,
hgroup,
main,
menu,
nav,
section,
summary {
  display: block;
}
audio,
canvas,
progress,
video {
  display: inline-block;
  vertical-align: baseline;
}
audio:not([controls]) {
  display: none;
  height: 0;
}
[hidden],
template {
  display: none;
}
a {
  background-color: transparent;
}
a:active,
a:hover {
  outline: 0;
}
abbr[title] {
  border-bottom: 1px dotted;
}
b,
strong {
  font-weight: 700;
}
dfn {
  font-style: italic;
}
h1 {
  font-size: 2em;
  margin: 0.67em 0;
}
mark {
  background: #ff0;
  color: #000;
}
small {
  font-size: 80%;
}
sub,
sup {
  font-size: 75%;
  line-height: 0;
  position: relative;
  vertical-align: baseline;
}
sup {
  top: -0.5em;
}
sub {
  bottom: -0.25em;
}
img {
  border: 0;
}
svg:not(:root) {
  overflow: hidden;
}
figure {
  margin: 1em 40px;
}
hr {
  box-sizing: content-box;
  height: 0;
}
pre {
  overflow: auto;
}
code,
kbd,
pre,
samp {
  font-family: monospace, monospace;
  font-size: 1em;
}
button,
input,
optgroup,
select,
textarea {
  color: inherit;
  font: inherit;
  margin: 0;
}
button {
  overflow: visible;
}
button,
select {
  text-transform: none;
}
button,
html input[type="button"],
input[type="reset"],
input[type="submit"] {
  -webkit-appearance: button;
  cursor: pointer;
}
button[disabled],
html input[disabled] {
  cursor: default;
}
button::-moz-focus-inner,
input::-moz-focus-inner {
  border: 0;
  padding: 0;
}
input {
  line-height: normal;
}
input[type="checkbox"],
input[type="radio"] {
  box-sizing: border-box;
  padding: 0;
}
input[type="number"]::-webkit-inner-spin-button,
input[type="number"]::-webkit-outer-spin-button {
  height: auto;
}
input[type="search"] {
  -webkit-appearance: textfield;
  box-sizing: content-box;
}
input[type="search"]::-webkit-search-cancel-button,
input[type="search"]::-webkit-search-decoration {
  -webkit-appearance: none;
}
fieldset {
  border: 1px solid silver;
  margin: 0 2px;
  padding: 0.35em 0.625em 0.75em;
}
legend {
  border: 0;
  padding: 0;
}
textarea {
  overflow: auto;
}
optgroup {
  font-weight: 700;
}
table {
  border-collapse: collapse;
  border-spacing: 0;
}
td,
th {
  padding: 0;
}
h1 {
  font-weight: 700;
  color: rgba(2, 5, 53, 0.75);
  font-size: 48px;
  line-height: 1;
  margin: 30px 0 20px;
}
h2 {
  color: rgba(2, 5, 53, 0.75);
}
@media (max-width: 600px) {
  h1 {
    font-size: 30px;
    margin-top: 30px;
  }
}
a {
  color: #1abc9c;
  transition: color 0.3s;
}
a:hover {
  color: #f90;
  transition-duration: 0s;
}
p,
li {
  font-size: 18px;
  line-height: 1.5;
  color: #111;
}
p {
  margin-top: 0;
  margin-bottom: 20px;
}
.small {
  font-size: 12px;
}
.embed-code {
  padding: 5px;
  font-family: courier;
}
@media (max-width: 1000px) {
  p,
  li {
    font-size: 16px;
  }
}
@media (max-width: 700px) {
  p,
  li {
    font-size: 14px;
  }
}
body {
  font-family: open sans, sans-serif;
}
.body--shaded {
  background: #e9e9e9;
}
html,
body {
  margin: 0;
  padding: 0;
  height: 100%;
}
.wrapper {
  max-width: 1200px;
  background: #fff;
  box-shadow: 0 0 3px 0 #c8c8c8;
  min-height: 100%;
  height: auto !important;
  height: 100%;
  margin: 0 auto -62px;
}
.fullscreen .wrapper {
  max-width: 100%;
}
.main {
  width: 90%;
  overflow: hidden;
  margin: 0 auto;
}
.lead {
  font-size: 1.4em;
}
hr {
  margin: 20px 0;
  border: 0;
  border-top: 1px solid #ecf0f1;
}
.hr--margin-large {
  margin: 60px 0;
}
#academo-banner {
  padding: 10px;
  background: rgba(0, 0, 0, 0.6);
  position: fixed;
  top: 0;
  left: 0;
  color: #fff;
  text-decoration: none;
}
#academo-banner:hover {
  color: #1abc9c;
}
.social-buttons {
  min-height: 40px;
  overflow: hidden;
}
.social-button {
  display: block;
  float: left;
  padding: 0 10px 10px 0;
}
.social-button--google-classroom {
  min-width: 32px;
}
.social-button--facebook a,
.social-button--twitter a {
  background: url(/img/social-media-sprite.png);
  background-size: 136px 54px;
  display: block;
  margin-top: 5px;
}
.social-button--patreon a:hover {
  opacity: 0.85;
}
.social-button--twitter a {
  width: 63px;
  height: 26px;
}
.social-button--twitter a:hover {
  background-position: 0 24px;
}
.social-button--facebook a {
  width: 61px;
  height: 25px;
  background-position: 61px 0;
}
.social-button--facebook a:hover {
  background-position: 61px 24px;
}
@media (max-width: 1200px) {
  .wrapper {
    margin-top: 0;
  }
}
.header {
  background: #fff;
}
.header-upper {
  background: #020535;
  overflow: hidden;
  padding: 25px;
}
.header-upper .header-inner {
  position: relative;
}
.logo {
  font-size: 32px;
  position: absolute;
  top: -10px;
  left: 0;
  text-transform: lowercase;
}
.logo img {
  width: 40px;
  vertical-align: middle;
  margin-right: 10px;
}
.header-lower {
  background: rgba(2, 5, 53, 0.85);
  overflow: hidden;
  padding: 10px 20px;
  border-top: solid 1px #1abc9c;
}
.header a {
  text-decoration: none;
  color: rgba(255, 255, 255, 0.95);
}
.header a:hover,
.header a.current {
  color: #f90;
}
.header-inner {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
}
.nav {
  float: right;
  padding: 0;
  margin: 0 0 0 40px;
}
.nav--secondary {
  float: left;
  margin-left: 0;
}
.nav li {
  float: left;
  list-style: none;
  margin-left: 20px;
}
.nav--secondary li {
  margin-left: 0;
  margin-right: 20px;
}
.sponsor-wrapper {
  padding: 20px 0;
  width: 90%;
  margin: 20px auto;
  box-sizing: border-box;
}
.sponsor-wrapper a {
  float: right;
}
.sposor-wrapper img {
  width: 100%;
}
.nav--primary .social--facebook {
  margin-left: 0;
}
@media (max-width: 800px) {
  .header-upper {
/*     padding: 15px 20px; */
  }
  .logo {
    position: static;
    float: left;
    font-size: 26px;
    top: -6px;
    margin-right: 20px;
  }
  .logo img {
    width: 30px;
    margin-right: 5px;
  }
  .header a {
    font-size: 16px;
  }
  .nav--primary {
    margin-top: 10px;
    margin-left: 0;
    float: left;
    clear: both;
  }
  .nav--primary li {
    margin-left: 0;
    margin-right: 20px;
  }
}
@media (max-width: 600px) {
  .nav--primary .social--twitter,
  .nav--primary .social--facebook {
    position: absolute;
    top: 0;
    right: 20px;
  }
  .nav--primary .social--facebook {
    right: 0;
  }
}
.thumbnails {
  margin: 0 -18px;
  padding: 0;
  overflow: hidden;
}
.thumbnails li {
  list-style: none;
  float: left;
  margin: 20px;
  width: calc(25% - 40px);
}
.thumbnails li:nth-child(4n + 1) {
  clear: both;
}
.thumbnail-title {
  font-size: 14px;
  color: #333;
  font-weight: 700;
  transition: color 0.3s;
}
.thumbnails a {
  text-decoration: none;
  color: #666;
  transition: color 0.3s;
  display: block;
}
.thumbnails a:hover .thumbnail-title {
  color: #f90;
  transition-duration: 0s;
}
.thumbnails img:not(.no-image-styles) {
  border: solid 1px #c8c8c8;
  transition: opacity 0.3s;
  width: 100%;
}
.thumbnails img:not(.no-image-styles):hover {
  opacity: 0.85;
  transition-duration: 0s;
}
.sponsored-tile img {
  height: auto;
}
@media (max-width: 880px) {
  .thumbnails li {
    width: calc(33% - 40px);
  }
  .thumbnails li:nth-child(4n + 1) {
    clear: none;
  }
  .thumbnails li:nth-child(3n + 1) {
    clear: both;
  }
}
@media (max-width: 600px) {
  .thumbnails li {
    width: calc(50% - 40px);
  }
  .thumbnails li:nth-child(4n + 1) {
    clear: none;
  }
  .thumbnails li:nth-child(3n + 1) {
    clear: none;
  }
  .thumbnails li:nth-child(2n + 1) {
    clear: both;
  }
}
.home .main {
  text-align: center;
}
.home .thumbnails li {
  float: none;
  display: inline-block;
  vertical-align: top;
}
.home .main p {
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}
.home .logos {
  list-style-type: none;
  padding: 0;
  max-width: 800px;
  margin-left: auto;
  margin-right: auto;
}
.home .logos li {
  display: inline-block;
  vertical-align: top;
}
.home .logos img {
  -webkit-filter: grayscale(100%);
  -moz-filter: grayscale(100%);
  filter: grayscale(100%);
  opacity: 0.6;
  margin: 20px;
  transition: all 0.5s;
}
.home .logos img:hover {
  -webkit-filter: grayscale(0%);
  -moz-filter: grayscale(0%);
  filter: grayscale(0%);
  opacity: 1;
  transition-duration: 0s;
}
.tweets {
  overflow: hidden;
  width: 90%;
  max-width: 1000px;
  margin: 0 auto;
  text-align: center;
}
.tweet {
  width: 30%;
  display: inline-block;
  padding: 10px;
  box-sizing: border-box;
  vertical-align: top;
}
blockquote.twitter-tweet {
  display: inline-block;
  font-family: helvetica neue, Roboto, segoe ui, Calibri, sans-serif;
  font-size: 12px;
  font-weight: 700;
  line-height: 16px;
  border-color: #eee #ddd #bbb;
  border-radius: 5px;
  border-style: solid;
  border-width: 1px;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.15);
  margin: 10px 5px;
  padding: 0 16px 16px;
  max-width: 468px;
}
blockquote.twitter-tweet p {
  font-size: 16px;
  font-weight: 400;
  line-height: 20px;
  margin-top: 20px;
}
blockquote.twitter-tweet a {
  color: inherit;
  font-weight: 400;
  text-decoration: none;
  outline: 0;
}
blockquote.twitter-tweet a:hover,
blockquote.twitter-tweet a:focus {
  text-decoration: underline;
}
@media (max-width: 1000px) {
  .tweet {
    width: 40%;
    display: inline-block;
    margin: 0 auto;
  }
}
@media (max-width: 730px) {
  .tweets {
    width: 100%;
  }
  .tweet {
    display: block;
    width: 100%;
    margin: 0 auto;
  }
}
.tags a {
  text-decoration: none;
  padding: 5px 10px;
  display: inline-block;
  margin: 0 10px 10px 0;
  background: #e9e9e9;
  color: #666;
  transition: background 0.3s;
  font-size: 16px;
  text-transform: capitalize;
}
.tags a:hover {
  background: #8ddece;
  transition-duration: 0s;
}
#demo {
  margin-bottom: 20px;
}
#demo,
.demo-description {
  float: left;
  width: 800px;
  width: calc(100% - 260px);
}
.demo--wide {
  width: 100% !important;
}
.demo-description {
  margin-bottom: 60px;
  max-width: 700px;
  margin-top: 60px;
}
.video-wrapper {
  margin: 40px auto;
}
.video-wrapper iframe {
  margin: 0 auto;
  display: block;
}
.responsive-video-wrapper {
  position: relative;
  padding-bottom: 56.25%;
  height: 0;
}
.responsive-video-wrapper .responsive-video {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
}
#disqus_thread {
  margin-top: 60px;
}
@media (max-width: 1120px) {
  .demo-description {
    margin-left: 0;
  }
}
@media (max-width: 768px) {
  #demo,
  .demo-description {
    width: 100%;
    margin: 0 0 20px;
  }
}
.demo-description h3 {
  margin: 40px 0 0;
}
#ui-container,
.sidebar {
  float: right;
  width: 240px;
  background: #e9e9e9;
  padding: 20px;
  margin-bottom: 20px;
  box-sizing: border-box;
}
.sidebar {
  margin-top: 60px;
}
.sidebar .thumbnails {
  padding: 2px;
  margin: 0;
}
.sidebar h3 {
  margin-top: 0;
}
.preamble hr {
  margin-top: 0;
}
.credits li {
  font-size: 16px;
}
.sidebar .thumbnails li {
  width: 100%;
  margin: 0 0 20px;
}
.sidebar .thumbnails li:nth-child(4n + 1) {
  clear: none;
}
@media (max-width: 1020px) {
  .sidebar {
    width: 100%;
    margin: 0 0 20px;
  }
  .sidebar .thumbnails li {
    margin: 20px;
    width: calc(33% - 40px);
  }
  .sidebar .thumbnails li:nth-child(3n + 1) {
    clear: both;
  }
}
@media (max-width: 600px) {
  .sidebar .thumbnails li {
    width: calc(50% - 40px);
  }
  .sidebar .thumbnails li:nth-child(3n + 1) {
    clear: none;
  }
  .sidebar .thumbnails li:nth-child(2n + 1) {
    clear: both;
  }
}
@media (max-width: 320px) {
  .sidebar .thumbnails li {
    width: 100%;
    margin-left: 0;
  }
  .sidebar .thumbnails li img {
    width: 99%;
  }
}
.subcategory-list h3 {
  margin-bottom: 0;
}
.category-description {
  max-width: 800px;
}
.contact-form {
  max-width: 600px;
}
#search-query {
  width: 100%;
  max-width: 300px;
  padding: 5px;
}
.about p {
  max-width: 620px;
}
.noUi-target * {
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  box-sizing: border-box;
  -webkit-touch-callout: none;
  -ms-touch-action: none;
  cursor: default;
}
.noUi-base {
  width: 100%;
  height: 20px;
  position: relative;
  max-width: 100%;
  max-height: 100%;
  border: 1px solid #bfbfbf;
  z-index: 1;
}
.noUi-handle {
  background: #eee;
  height: 44px;
  width: 44px;
  border: 1px solid #bfbfbf;
  margin: -3px 0 0 -10px;
}
.noUi-active {
  background: #e9e9e9;
}
.noUi-connect {
  background: Teal;
}
.noUi-background {
  background: #ddd;
}
.noUi-origin {
  position: absolute;
  right: 0;
  top: 0;
  bottom: 0;
  z-index: 0;
  border-radius: inherit;
}
.noUi-origin-upper {
  background: inherit !important;
}
.noUi-z-index {
  z-index: 10;
}
.noUi-vertical {
  width: 40px;
  height: 100%;
}
.noUi-vertical .noUi-origin {
  bottom: 0;
  left: 0;
}
.noUi-vertical .noUi-handle {
  margin: -23px 0 0 -3px;
}
.noUi-target[disabled] .noUi-base {
  background: #999;
}
.noUi-target[disabled] .noUi-connect {
  background: #bbb;
}
.noUi-state-tap .noUi-origin {
  -webkit-transition: left 0.3s, top 0.3s;
  transition: left 0.3s, top 0.3s;
}
.noUi-base {
  height: 11px;
  border-color: #ccc;
}
.noUi-background {
  background-color: #fff;
}
.noUi-connect {
  margin-top: 15px;
  background: #2c3e50;
  float: left;
}
.noUi-handle {
  cursor: pointer;
  margin-top: -8px;
  height: 25px;
  width: 18px;
  background-color: #d4d4d4;
  border: 0 solid rgba(0, 0, 0, 0.1);
  border-radius:3px;
  outline: none;
}
.noUi-handle:hover {
  background: #288edf;
}
.noUi-handle {
  background: #eee;
  border: 1px solid #ccc;
}
.noUi-active {
  background-color:hsl(213,100%,41%)!important;
}
fieldset {
  padding: 0;
  margin: 0;
  border: 0;
}
label {
  display: inline-block;
  margin-bottom: 5px;
  font-weight: 700;
}
input[type="search"] {
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  box-sizing: border-box;
}
input[type="radio"],
input[type="checkbox"] {
  margin: 4px 0 0;
  margin-top: 1px \9;
  line-height: normal;
}
input[type="file"] {
  display: block;
}
select[multiple],
select[size] {
  height: auto;
}
select optgroup {
  font-size: inherit;
  font-style: inherit;
  font-family: inherit;
}
input[type="file"]:focus,
input[type="radio"]:focus,
input[type="checkbox"]:focus {
  outline: thin dotted #333;
  outline: 5px auto -webkit-focus-ring-color;
  outline-offset: -2px;
}
.form-control {
  display: block;
  width: 100%;
  height: 34px;
  padding: 6px 12px;
  font-size: 14px;
  line-height: 1.428571429;
  color: #555;
  vertical-align: middle;
  background-color: #fff;
  background-image: none;
  border: 1px solid #ccc;
  transition: border-color ease-in-out 0.15s, box-shadow ease-in-out 0.15s;
}
.form-control:focus {
  border-color: #66afe9;
  outline: 0;
  -webkit-box-shadow: inset 0 1px 1px rgba(0, 0, 0, 0.075),
    0 0 8px rgba(102, 175, 233, 0.6);
  box-shadow: inset 0 1px 1px rgba(0, 0, 0, 0.075),
    0 0 8px rgba(102, 175, 233, 0.6);
}
.form-control:-moz-placeholder {
  color: #999;
}
.form-control::-moz-placeholder {
  color: #999;
}
.form-control:-ms-input-placeholder {
  color: #999;
}
.form-control::-webkit-input-placeholder {
  color: #999;
}
.form-control[disabled],
.form-control[readonly],
fieldset[disabled] .form-control {
  cursor: not-allowed;
}
.form-group {
  margin-bottom: 15px;
}
.radio,
.checkbox {
  display: block;
  min-height: 20px;
  margin-bottom: 10px;
  padding-left: 20px;
  vertical-align: middle;
}
.radio label,
.checkbox label {
  display: inline;
  margin-bottom: 0;
  font-weight: 400;
  cursor: pointer;
}
.radio input[type="radio"],
.radio-inline input[type="radio"],
.checkbox input[type="checkbox"],
.checkbox-inline input[type="checkbox"] {
  float: left;
  margin-left: -20px;
}
.radio + .radio,
.checkbox + .checkbox {
  margin-top: -5px;
}
.radio-inline,
.checkbox-inline {
  display: inline-block;
  padding-left: 20px;
  margin-bottom: 0;
  vertical-align: middle;
  font-weight: 400;
  cursor: pointer;
}
.radio-inline + .radio-inline,
.checkbox-inline + .checkbox-inline {
  margin-top: 0;
  margin-left: 10px;
}
input[type="radio"][disabled],
input[type="checkbox"][disabled],
.radio[disabled],
.radio-inline[disabled],
.checkbox[disabled],
.checkbox-inline[disabled],
fieldset[disabled] input[type="radio"],
fieldset[disabled] input[type="checkbox"],
fieldset[disabled] .radio,
fieldset[disabled] .radio-inline,
fieldset[disabled] .checkbox,
fieldset[disabled] .checkbox-inline {
  cursor: not-allowed;
}
.form-control-static {
  margin-bottom: 0;
}
.help-block {
  display: block;
  margin-top: 5px;
  margin-bottom: 10px;
  color: #737373;
}
@media (min-width: 768px) {
  .form-inline .form-group {
    display: inline-block;
    margin-bottom: 0;
    vertical-align: middle;
  }
  .form-inline .form-control {
    display: inline-block;
  }
  .form-inline .radio,
  .form-inline .checkbox {
    display: inline-block;
    margin-top: 0;
    margin-bottom: 0;
    padding-left: 0;
  }
  .form-inline .radio input[type="radio"],
  .form-inline .checkbox input[type="checkbox"] {
    float: none;
    margin-left: 0;
  }
}
.input-group {
  position: relative;
  display: table;
  border-collapse: separate;
}
.input-group.col {
  float: none;
  padding-left: 0;
  padding-right: 0;
}
.input-group .form-control {
/*   width: 100%; */
  width: 50px;
  position:relative;
  float:right;
  margin-bottom: 0;
}
.input-group-addon,
.input-group .form-control {
  display: table-cell;
}
.input-group-addon {
  width: 1%;
  white-space: nowrap;
  vertical-align: middle;
}
.input-group-addon {
  padding: 6px 12px;
  font-size: 14px;
  font-weight: 400;
  line-height: 1;
  color: #555;
  text-align: center;
  background-color: #eee;
  border: 1px solid #ccc;
}
.input-group-addon input[type="radio"],
.input-group-addon input[type="checkbox"] {
  margin-top: 0;
}
.input-group-addon:first-child {
  border-right: 0;
}
.input-group-addon:last-child {
  border-left: 0;
}
table {
  max-width: 100%;
  border-collapse: collapse;
  border-spacing: 0;
}
.table {
  width: 100%;
  margin-bottom: 20px;
}
.table th,
.table td {
  padding: 8px;
  line-height: 20px;
  text-align: left;
  vertical-align: top;
  border-top: 1px solid #ddd;
}
.table th {
  font-weight: 700;
}
.table thead th {
  vertical-align: bottom;
}
.table thead:first-child tr:first-child th,
.table thead:first-child tr:first-child td {
  border-top: 0;
}
.table-bordered {
  border: 1px solid #ddd;
  border-left: 0;
}
.table-bordered th,
.table-bordered td {
  border-left: 1px solid #ddd;
}
.table-bordered thead:first-child tr:first-child th,
.table-bordered tbody:first-child tr:first-child th,
.table-bordered tbody:first-child tr:first-child td {
  border-top: 0;
} /*!! Props to Brad Bodine for the Checkboxes! http://codepen.io/bbodine1/details/novBm*/
input[type="checkbox"] {
  visibility: hidden;
}
.checkbox {
  position: relative;
}
#ui-container .checkbox label {
  cursor: pointer;
  position: absolute;
  width: 20px;
  height: 14px;
  top: 0;
  left: 0;
  background: #fff;
  border: 1px solid #ccc;
  box-shadow: none;
}
.checkbox label:after {
  -ms-filter: "alpha(opacity=0)";
  filter: alpha(opacity=0);
  opacity: 0;
  content: "";
  position: absolute;
  width: 9px;
  height: 5px;
  background: 0 0;
  top: 4px;
  left: 4px;
  border: 3px solid #f90;
  border-top: none;
  border-right: none;
  -webkit-transform: rotate(-45deg);
  -moz-transform: rotate(-45deg);
  -o-transform: rotate(-45deg);
  -ms-transform: rotate(-45deg);
  transform: rotate(-45deg);
}
.checkbox label:hover::after {
  -ms-filter: "alpha(opacity=30)";
  filter: alpha(opacity=30);
  opacity: 0.1;
}
.checkbox input[type="checkbox"]:checked + label:after {
  -ms-filter: "alpha(opacity=100)";
  filter: alpha(opacity=100);
  opacity: 1;
}
.interface {
  margin-bottom: 20px;
  padding-bottom: 20px;
  border-bottom: 2px solid #ecf0f1;
  width: 100%;
}
.interface:first-of-type label {
  padding-top: 0;
}
.interface:last-of-type,
.interface.last {
  padding-bottom: 0;
  border-bottom: none;
}
.interface label {
  padding-top: 6px;
}
.interface .noUi-connect {
  max-width: 240px;
}
@media (max-width: 768px) {
  .interface .input,
  .interface .input-append {
    margin-right: 40px;
  }
  .interface .noUi-connect {
    margin-bottom: 15px;
  }
  .interface {
    width: 240px;
    float: left;
    margin-right: 60px;
  }
}
.with-units {
  text-align: right;
}
.interface.disabled {
  opacity: 0.5;
}
#ui-container {
  padding: 20px;
  background: #efefef;
  box-sizing: border-box;
}
#ui-container label,
#ui-container button {
  font-size: 13px;
  color: #333;
  font-weight: 800;
  -webkit-appearance: none;
  width: 100%;
}
#ui-container button {
  padding: 10px;
  background: #ddd;
  border: none;
  border-bottom: solid 2px #ccc;
  transition: background 0.3s;
}
#ui-container button:hover {
  background: #8ddece;
  border-color: #53cdb5;
  transition-duration: 0s;
}
#ui-container button:active {
  background: #31c3a6;
  border-color: #1abc9c;
  transition-duration: 0s;
}
#ui-container button:focus {
  outline: none;
}
#ui-container .interface {
  margin-bottom: 0;
}
#ui-container input {
  -webkit-appearance: none;
}
.user-input-numerical {
  -moz-box-sizing: border-box;
  box-sizing: border-box;
}
.user-input-string {
  -moz-box-sizing: border-box;
  box-sizing: border-box;
}
.user-input-textarea {
  -moz-box-sizing: border-box;
  box-sizing: border-box;
  height: 100px;
  white-space: nowrap;
  overflow: auto;
}
.interface input[readonly] {
  border: none;
  padding: 5px 5px 5px 0;
  width: 100%;
  background: #efefef;
  cursor: text;
}
@media (max-width: 768px) {
  #ui-container,
  .sidebar {
    width: 100%;
    float: left;
  }
}
@media (max-width: 480px) {
  #ui-container {
    border: solid 1px #ccc;
    max-height: 250px;
    overflow: scroll;
  }
  ::-webkit-scrollbar {
    -webkit-appearance: none;
    width: 4px;
  }
  ::-webkit-scrollbar-thumb {
    border-radius: 4px;
    background-color: rgba(0, 0, 0, 0.3);
    -webkit-box-shadow: 0 0 1px rgba(255, 255, 255, 0.5);
  }
}
.footer {
  color: #fff;
  background: #11172b;
  width: 100%;
  text-align: right;
  max-width: 1200px;
  margin: 0 auto;
  height: 62px;
}
.footer br {
  display: none;
}
.footer p {
  color: #fff;
  font-size: 15px;
  margin-bottom: 0;
}
.footer-inner {
  padding: 20px;
}
.push {
  height: 62px;
}
@media (max-width: 520px) {
  .footer {
    text-align: left;
  }
  .footer-inner {
    padding: 10px 20px;
  }
  .footer p {
    font-size: 13px;
  }
  .footer br {
    display: block;
  }
}

#color_display {
  height: 312px;
}
#color span {
  font-weight: bold;
}
#color {
  float: left;
}
#color p {
  line-height: 2;
}

#demo {
  width: 150px;
}

#ui-container {
  /*   position:relative;   */
  /*   float:unset; */
/*   float: left; */
  width:400px;
}

.interface .noUi-connect {
  max-width: 640px;
}

#rainbowArea{
  position:relative;
/*   border: 1px solid white; */
}

.pointRepere{
  color:white;
  border: 1px dashed transparent;
  border-right:none;
  background:transparent;
   width: 0px;
  height:80px;
/*   border-radius:100%; */
/*   margin:10px; */
  position:relative;
  top:311px;
/*   margin:10px; */
/*   left:275px; */
/*   left:0px; */
}

.pointRepere::before{
  content:"";
   border: 1px solid hsla(0,0%,0%,.5);
border-radius:6px;
  position:absolute;
  
  width:5px;
  height:86px;
/*   padding:0px; */
  top:-4px;
  left:-4px;
}
!

JS 

              
                /* This code comes from Academo.org */
var demo = new Demo({
  ui: {
    wavelength: {
      title: "Wavelength, human perception",
      value: 550,
      units: "nm",
      range: [380, 780],
      resolution: 1
    }
  },
  color: null,
  init: function () {
    $("#demo").append("<div id='color_display'></div>");
    $("#ui-container").append("<div id='color'></div>");
    this.update();
    this.renderRainbow();
  },
  update: function (e) {
    this.color = this.nmToRGB(this.ui.wavelength.value);
    $("#color_display").css("background-color", this.rgbToHex(this.color));
    var colHtml = "<p><span>Color:</span><br />rgb(";
    colHtml += this.color[0] + ", " + this.color[1] + ", " + this.color[2];
    colHtml += ")<br />Hex: " + this.rgbToHex(this.color) + "<br />";
    colHtml += chroma(this.rgbToHex(this.color)).css("hsl");
    colHtml += "</p>";
    $("#color").html(colHtml);
    var offset = 10/2 +1 +20;
    // console.log("HERE",   (chroma(this.rgbToHex(this.color)).hsl()[0])-180 );
        
    document.getElementById("refPoint").style.setProperty("left",(780 *(this.ui.wavelength.value- 550) / 568)+232 + "px");
    
  document.getElementById("refPoint").style.setProperty("border-color",
  "hsl(" + (chroma(this.rgbToHex(this.color)).hsl()[0] + 180) + ",100%,50%)")
  },
  
  nmToRGB: function (wavelength) {
    var Gamma = 0.8,
      IntensityMax = 255,
      factor,
      red,
      green,
      blue;
    if (wavelength >= 380 && wavelength < 440) {
      red = -(wavelength - 440) / (440 - 380);
      green = 0.0;
      blue = 1.0;
    } else if (wavelength >= 440 && wavelength < 490) {
      red = 0.0;
      green = (wavelength - 440) / (490 - 440);
      blue = 1.0;
    } else if (wavelength >= 490 && wavelength < 510) {
      red = 0.0;
      green = 1.0;
      blue = -(wavelength - 510) / (510 - 490);
    } else if (wavelength >= 510 && wavelength < 580) {
      red = (wavelength - 510) / (580 - 510);
      green = 1.0;
      blue = 0.0;
    } else if (wavelength >= 580 && wavelength < 645) {
      red = 1.0;
      green = -(wavelength - 645) / (645 - 580);
      blue = 0.0;
    } else if (wavelength >= 645 && wavelength < 781) {
      red = 1.0;
      green = 0.0;
      blue = 0.0;
    } else {
      red = 0.0;
      green = 0.0;
      blue = 0.0;
    }
    // Let the intensity fall off near the vision limits
    if (wavelength >= 380 && wavelength < 420) {
      factor = 0.3 + (0.7 * (wavelength - 380)) / (420 - 380);
    } else if (wavelength >= 420 && wavelength < 701) {
      factor = 1.0;
    } else if (wavelength >= 701 && wavelength < 781) {
      factor = 0.3 + (0.7 * (780 - wavelength)) / (780 - 700);
    } else {
      factor = 0.0;
    }
    if (red !== 0) {
      red = Math.round(IntensityMax * Math.pow(red * factor, Gamma));
    }
    if (green !== 0) {
      green = Math.round(IntensityMax * Math.pow(green * factor, Gamma));
    }
    if (blue !== 0) {
      blue = Math.round(IntensityMax * Math.pow(blue * factor, Gamma));
    }
    return [red, green, blue];
  },
  toHex: function (number) {
    //converts a decimal number into hex format
    var hex = number.toString(16);
    if (hex.length < 2) {
      hex = "0" + hex;
    }
    return hex;
  },
  rgbToHex: function (color) {
    // alert("Here!");
    //takes an 3 element array (r,g,b) and returns a hexadecimal color
    var hexString = "#";
    for (var i = 0; i < 3; i++) {
      hexString += this.toHex(color[i]);
    }
    return hexString;
  },
  renderRainbow: function () {
    //render all the colours - used to generate the thumbnail image
    var canvas = document.createElement("canvas");
    var ctx = canvas.getContext("2d");
    canvas.width = 550;
    canvas.height = 80;
    canvas.id="rainbowArea";
    $("#demo").append(canvas);
    for (var i = 0; i < canvas.width; i++) {
      ctx.fillStyle = this.rgbToHex(
        this.nmToRGB(
          this.map(
            i,
            0,
            canvas.width,
            this.ui.wavelength.range[0],
            this.ui.wavelength.range[1]
          )
        )
      );
      ctx.fillRect(i, 0, 1, canvas.height);
      ctx.fillStyle = "#fff";
      ctx.fill();

      // add point on the specrtum
      // ctx.beginPath();
      // ctx.arc(
      //   this.ui.wavelength.value -780 + 550,
      //   canvas.height / 2,
      //   10,
      //   0,
      //   2 * Math.PI
      // );
      // ctx.stroke();
    }
  },
  map: function (value, minFrom, maxFrom, minTo, maxTo) {
    //http://stackoverflow.com/questions/4154969/how-to-map-numbers-in-range-099-to-range-1-01-0
    return minTo + (maxTo - minTo) * ((value - minFrom) / (maxFrom - minFrom));
  }
});
!
999px

Console