<code class="code-container" content="// Jane 💜">
  <div class="glow-container">
    <div class="augs" data-augmented-ui></div>
  </div>
  <section class="augs bg" data-augmented-ui>
    <button class="dots" onclick="changeMode()" title="change mode"></button>
    <input value="propjockey.io">
    <div class="code highcontrast-dark">
      <textarea id="code">
@keyframes cast-bit-to-space-toggle {
  to { --cbtst-space-toggle: ; }
}

@property --cbtst-space-toggle {
  syntax: "*";
  initial-value: initial;
  inherits: false;
}

:where(.cbtst) {
  --cbtst-animation: cast-bit-to-space-toggle
    1ms linear both var(--cbtst-bit, 0);
  animation: var(--cbtst-animation);
}

/* usage */
.my-el.cbtst {
  --cbtst-bit: 1; /* provide input value of 0 or 1 */
  /* var(--cbtst-space-toggle) is the output */
}
      </textarea>
    </div>
  </section>
</div>
.code-container {
  resize: both;
  overflow: hidden;
  margin: auto;
  width: 80vw;
  height: 80vh;
  min-width: 420px;
  min-height: 255px;
  position: relative;
  --glow-margin: 70px;
  filter: drop-shadow(0 0 75px rgb(128 0 255 / 0.25));
}

.code-container::before {
  content: attr(content);
  position: absolute;
  bottom: 90px;
  right: 90px;
  z-index: 999;
  color: rgb(255 200 255 / 0.5);
  text-shadow: 0 0 12px rebeccapurple;
  letter-spacing: 0.1em;
}

.code-container::after {
  content: "";
  background: linear-gradient(
    to right,
    transparent,
    black 25px, black 110px,
    transparent 110px 175px,
    black 175px, black calc(100% - 25px),
    transparent
  );
  position: absolute;
  top: 125px;
  left: var(--glow-margin);
  right: var(--glow-margin);
  height: 4px;
  display: block;
  z-index: 90;
  opacity: 0.5;
}

.glow-container {
  position: absolute;
  inset: 0;
  display: grid;
  z-index: 2;
  pointer-events: none;
  --glow: drop-shadow(0 0 1px violet);
  filter: var(--glow) brightness(1.5) drop-shadow(0 0 10px violet);
}

.augs {
  --aug-rect-l1: initial;
  --aug-l1-width: 110px;
  --aug-l1-height: 4px;
  --aug-l-center: 57px;
  
  --aug-rect-r1: initial;
  --aug-r1-width: (100% - 125px - 50px);
  --aug-r1-height: 4px;
  --aug-r-center: 57px;
  
  --aug-clip-tr1: initial;
  --aug-tr1-alt-join-out: initial;
  --aug-tr1: 17px;
  --aug-clip-tr2: initial;
  --aug-tr2: 17px;
  --aug-tr-extend1: 50px;
  
  --aug-round-tl1: initial;
  --aug-tl1: 8px;
  --aug-round-br1: initial;
  --aug-br1: 8px;
  margin: auto;
  width: calc(100% - var(--glow-margin) * 2);
  height: calc(100% - var(--glow-margin) * 2);
}

.glow-container .augs {
  --aug-border: initial;
  --aug-border-all: 2px;
  --aug-border-bg: linear-gradient(to bottom left, rebeccapurple, orange);
}

section.augs {
  position: absolute;
  inset: 0;
  margin: auto;
  --aug-inlay: initial;
  --aug-inlay-all: 2px;
  --aug-inlay-bg: url(http://augmented-ui.com/img/propjockey.png)
    center 70% / auto 70% no-repeat;
  --aug-inlay-opacity: 0.25;
}
section.augs::before {
  filter: brightness(0.2) blur(10px);
}

.dots {
  position: absolute;
  top: 2px;
  left: 2px;
  width: 110px;
  height: 50px;
  --red: #fc199a;
  --yellow: #ffcc00;
  --green: #61e2ff;
  --close: radial-gradient(circle, var(--red), var(--red) 7px, transparent 8px);
  --min: radial-gradient(circle, var(--yellow), var(--yellow) 7px, transparent 8px);
  --max: radial-gradient(circle, var(--green), var(--green) 7px, transparent 8px);
  background: var(--close) -28px no-repeat,
              var(--min) -2px no-repeat,
              var(--max) 24px no-repeat;
  filter: brightness(0.5);
  opacity: 0.75;
  cursor: pointer;
  border: none;
}

input {
  position: absolute;
  top: 17px;
  left: 120px;
  width: calc(100% - 240px);
  background: transparent;
  color: rgb(255 200 255 / 0.5);
  text-shadow: 0 0 12px rebeccapurple;
  border: none;
  text-align: center;
  letter-spacing: 0.1em;
}

.code {
  position: absolute;
  inset: 80px 10px 10px 10px;
  font-size: 20px;
  color: white;
  filter: brightness(1.2);
}
.code * {
  font-size: 18px;
  font-weight: normal;
  color: #b5b4b6;
  font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, monospace;
}

body {
  display: grid;
  min-height: 100vh;
  width: 100vw;
  --c: rgb(0 0 0 / 0.95);
  --bgb: linear-gradient(var(--c), var(--c));
  --bg: repeating-conic-gradient(
    from 7.5deg at center center,
    hsl(200, 100%, 0%) 0deg 15deg,
    hsl(200, 100%, 60%) 10deg 30deg
  );
  background: var(--bgb), var(--bg), black;
}

* {
  font: normal 1em sans-serif;
  box-sizing: border-box;
  padding: 0;
  margin: 0;
}

/* https://marketplace.visualstudio.com/items?itemName=webrender.synthwave-x-fluoromachine */
.bg {
  background: repeating-linear-gradient(
    to top,
    rgba(255, 255, 255, 0.03) 0px 2px,
    transparent 2px 4px
  ),
  linear-gradient(to bottom, #200933 75%, #3d0b43);
}
.bg::after{
  content:'';
  height:50%;
  width:100%;
  display:block;
  background-image:linear-gradient(90deg, rgba(252,25,154,.1) 1px, rgba(0,0,0,0) 1px), linear-gradient(0deg, rgba(252,25,154,.1) 1px, rgba(0,0,0,0) 1px);
  background-position:bottom;
  background-repeat:repeat;
  background-size:20px 20px;
  left: -25px;
  position: absolute;
  pointer-events: none;
  bottom: 0;
  transform: perspective(100px) rotateX(60deg);
  z-index: 0;
}

.CodeMirror-gutters {
  background: transparent;
  border: none;
  margin-right: 15px;
}
.CodeMirror {
  height: 100%;
  background: transparent;
}
.CodeMirror-linenumber {
  padding-right: 1em;
}
.CodeMirror-overlayscroll-horizontal div,
.CodeMirror-overlayscroll-vertical div {
  background: rgba(153, 99, 255, 0.5);
}
.CodeMirror-scrollbar-filler { display: none!important; }

/* codepen's highcontrast-dark theme */
.cm-header{font-weight:700}.cm-strong{font-weight:700}.cm-em{font-style:italic}:root{--editor-top-bar-background: black;--tab-bg: #131417;--tab-border-color: #2a2c33;--resizer-background: var(--editor-top-bar-background);--resizer-border: #242424}.sidebar-false .main-header,.sidebar-false .main-header .header-wrap,.editor-footer{background:var(--editor-top-bar-background)}.CodeMirror-cursor{border-left-color:#fff!important}.CodeMirror-selected{background:rgba(255,255,255,.05)}.CodeMirror-focused .CodeMirror-selected{background:rgba(255,255,255,.1)}.CodeMirror-matchingbracket{border-bottom:1px solid rgba(255,255,255,.5)}.CodeMirror-matchingtag{border-bottom:1px solid rgba(255,255,255,.3)}.cm-searching{background:#000;outline:2px solid rgba(255,255,255,.25)}.CodeMirror-hints,.emmet-abbreviation-preview{border:1px solid #5a5f73;background:#1e1f26}.CodeMirror-hint{color:#fff}li.CodeMirror-hint-active{background:#c7c9d3;color:#000}.project-editor-warning{background:rgba(255,255,255,.1)}.editor-footer{border-top-color:var(--resizer-border,var(--cp-color-6))}.cm-keyword{color:#ffdd40}.cm-atom{color:#a3d65a}.box-html .cm-atom{color:#ff3c41}.cm-def{color:#0ebeff}.cm-variable{color:#c7c9d3}.cm-variable-2{color:#47cf73}.cm-variable-3{color:#fff}.cm-header{color:#ff3c41}.cm-number{color:#2bc7b9}.cm-property{color:#5e91f2}.cm-attribute{color:#e3e4e8}.cm-builtin{color:#ae63e4}.cm-qualifier{color:#ffdd40}.cm-operator{color:#47cf73}.cm-meta{color:#0ebeff}.cm-string{color:#2bc7b9}.cm-string-2{color:#d75093}.cm-tag{color:#ffdd40}.box-css .cm-tag{color:#ff8d41}.cm-tag.cm-bracket{color:#9b9dad}.cm-comment{color:#88afbf}body.editor{background:#131417}.box.box.box,.editor .top-boxes,.CodeMirror-gutter-wrapper,body.project .editor-pane,body.project .editor{background:#131417}.box.box.box pre,.editor .top-boxes pre,.CodeMirror-gutter-wrapper pre,body.project .editor-pane pre,body.project .editor pre{color:#d5d7de}.CodeMirror-guttermarker-subtle,.CodeMirror-linenumber{color:rgba(113,119,144,.6)}#output pre::-webkit-scrollbar,#output iframe::-webkit-scrollbar{width:.5em;height:.5em}#output pre::-webkit-scrollbar-thumb,#output iframe::-webkit-scrollbar-thumb{background:#373c49}#output pre::-webkit-scrollbar-track,#output iframe::-webkit-scrollbar-track{background:0 0}.CodeMirror-simplescroll-horizontal div,.CodeMirror-simplescroll-vertical div{background:#373c49}.powers .mini-button{background:#444857}.powers .mini-button:hover,.powers .mini-button:focus{background:#c7c9d3}.powers .mini-button:hover svg,.powers .mini-button:focus svg{fill:#000}

/* theme overrides original source */
/* https://marketplace.visualstudio.com/items?itemName=webrender.synthwave-x-fluoromachine */
/* I just ported it to codemirror */

.highcontrast-dark .cm-header {
  font-weight: bold
}

.highcontrast-dark .cm-strong {
  font-weight: bold
}

.highcontrast-dark .cm-em {
  font-style: italic
}

.highcontrast-dark .CodeMirror-cursor {
  border-left-color: white !important
}

.highcontrast-dark .CodeMirror-selected {
  background: rgba(255,255,255,0.05)
}

.highcontrast-dark .CodeMirror-focused .CodeMirror-selected {
  background: rgba(255,255,255,0.1)
}

.highcontrast-dark .CodeMirror-matchingbracket {
  border-bottom: 1px solid rgba(255,255,255,0.5)
}

.highcontrast-dark .CodeMirror-matchingtag {
  border-bottom: 1px solid rgba(255,255,255,0.3)
}

.highcontrast-dark .powers {
  border-bottom: 1px solid rgba(255,255,255,0.05)
}

.highcontrast-dark .cm-searching {
  background: black;
  outline: 2px solid rgba(255,255,255,0.25)
}

.highcontrast-dark .CodeMirror-hints,
.highcontrast-dark .emmet-abbreviation-preview {
  border: 1px solid #5a5f73;
  background: #1e1f26
}

.highcontrast-dark .CodeMirror-hint {
  color: white
}

.highcontrast-dark li.CodeMirror-hint-active {
  background: #c7c9d3;
  color: black
}

.highcontrast-dark .project-editor-warning {
  background: rgba(255,255,255,0.1)
}

.highcontrast-dark .cm-atom {
  color: #9963ff;
}

.highcontrast-dark .box-html .cm-atom {
  color: #ff3c41
}

.highcontrast-dark .cm-def,
.highcontrast-dark .cm-variable-2,
.highcontrast-dark .cm-variable,
.highcontrast-dark .box-js .cm-variable + .cm-property {
  color: #61e2ff;
  text-shadow: 0 0 2px #001716, 0 0 5px #03edf933, 0 0 10px #ffff6633;
}

.highcontrast-dark .cm-header {
  color: #ff3c41
}
.highcontrast-dark .cm-builtin {
  color: #ae63e4
}

.highcontrast-dark .cm-number {
  color: #9963ff;
}


.highcontrast-dark .cm-operator,
.highcontrast-dark .cm-variable-3,
.highcontrast-dark .cm-attribute,
.highcontrast-dark .cm-property,
.highcontrast-dark .cm-keyword,
.highcontrast-dark .presentation > .cm-def,
.highcontrast-dark .cm-qualifier {
  color: #fc199a;
  text-shadow: 0 0 2px #393a33, 0 0 35px #ffffff44, 0 0 10px #fc199a, 0 0 2px #fc199a;
}
.highcontrast-dark .cm-operator,
.highcontrast-dark .cm-variable-3,
.highcontrast-dark .cm-attribute,
.highcontrast-dark .cm-property {
  font-style: italic;
}

.highcontrast-dark .cm-meta,
.highcontrast-dark .cm-meta + .cm-property,
.highcontrast-dark .cm-string,
.highcontrast-dark .cm-string-2 {
  color: #9963ff;
  text-shadow: none;
}

.highcontrast-dark .cm-tag,
.highcontrast-dark .cm-callee,
.highcontrast-dark .box-css .cm-tag,
.highcontrast-dark .cm-tag.cm-bracket,
.highcontrast-dark .box-js .cm-property  {
  color: #ffcc00;
  text-shadow: 0 0 2px #100c0f, 0 0 3px #ffaa0099, 0 0 5px #ffaa0099, 0 0 10px #ffaa0099;
  font-style: italic;
}

.highcontrast-dark .cm-comment {
  font-style: italic;
  color: #9963ff99;
  text-shadow: 0 0 2px #001716, 0 0 5px #03edf933, 0 0 10px #ffff6633;
}

body.editor.highcontrast-dark {
  background: #241b2f;
}

.highcontrast-dark .box.box.box,
.editor.highcontrast-dark .top-boxes,
.highcontrast-dark .CodeMirror-gutter-wrapper,
body.project.highcontrast-dark .editor-pane,
body.project.highcontrast-dark .editor {
  background: none;
}
.editor.highcontrast-dark .top-boxes {
  --swxfm__c: rgba(153, 99, 255);
  background: repeating-linear-gradient(
    to top,
    rgba(255, 255, 255, 0.03) 0px 2px,
    transparent 2px 4px
  ),
  linear-gradient(to bottom, #200933 75%, #3d0b43);
}
.editor.highcontrast-dark .top-boxes:after{
  content:'';
  height:300px;
  width:100%;
  display:block;
  background-image:linear-gradient(90deg, rgba(252,25,154,.1) 1px, rgba(0,0,0,0) 1px), linear-gradient(0deg, rgba(252,25,154,.1) 1px, rgba(0,0,0,0) 1px);
  background-position:bottom;
  background-repeat:repeat;
  background-size:20px 20px;
  left: -25px;
  position: absolute;
  pointer-events: none;
  bottom: 0;
  transform: perspective(100px) rotateX(60deg);
  z-index: 0;
}

.highcontrast-dark .box.box.box pre,
.editor.highcontrast-dark .top-boxes pre,
.highcontrast-dark .CodeMirror-gutter-wrapper pre,
body.project.highcontrast-dark .editor-pane pre,
body.project.highcontrast-dark .editor pre {
  color: #b5b4b6;
}

.highcontrast-dark .CodeMirror-guttermarker-subtle,
.highcontrast-dark .CodeMirror-linenumber {
  color: #8a2dc066;
  text-shadow: 0 0 2px #393a33, 0 0 35px #ffffff44, 0 0 10px #8a2dc066, 0 0 2px #8a2dc066;
}
let mode = "css"
const editor = CodeMirror.fromTextArea(code, {
  lineNumbers: true,
  styleActiveLine: true,
  matchBrackets: true,
  scrollbarStyle: "overlay",
  Tab: "indentMore",
  defaultTab: function(cm) {
    if (cm.somethingSelected()) cm.indentSelection("add");
    else cm.replaceSelection("  ", "end");
  },
  mode
})
editor.setOption("theme", "highcontrast-dark")
const x = document.querySelector(".code")
const ro = new ResizeObserver(entries => {
  editor.setSize(x.offsetWidth, x.offsetHeight)
})
ro.observe(document.querySelector(".code-container"))

const changeMode = () => {
  mode = mode === "css" ? "javascript" : "css"
  editor.setOption("mode", mode)
}
Run Pen

External CSS

  1. https://unpkg.com/[email protected]/augmented-ui.min.css
  2. https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.35.0/codemirror.css
  3. https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.58.1/addon/scroll/simplescrollbars.min.css

External JavaScript

  1. https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.58.1/codemirror.js
  2. https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.58.1/mode/javascript/javascript.js
  3. https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.58.1/mode/css/css.js
  4. https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.58.1/addon/scroll/simplescrollbars.min.js