.square {
    height: 200px;
    width: 200px;
    background-color: #555;
  }
  
    /*
  
  Online Python Tutor
  
  Copyright (C) Philip J. Guo
  
  Permission is hereby granted, free of charge, to any person obtaining a
  copy of this software and associated documentation files (the
  "Software"), to deal in the Software without restriction, including
  without limitation the rights to use, copy, modify, merge, publish,
  distribute, sublicense, and/or sell copies of the Software, and to
  permit persons to whom the Software is furnished to do so, subject to
  the following conditions:
  
  The above copyright notice and this permission notice shall be included
  in all copies or substantial portions of the Software.
  
  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
  CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
  TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
  SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  
  */
  
  /* Most recent color scheme redesign on 2012-08-19 */
  
  /* To prevent CSS namespace clashes, prefix all rules with:
       div.ExecutionVisualizer
  */
  
  
  /* reset some styles to nullify effects of existing stylesheets
     e.g., http://meyerweb.com/eric/tools/css/reset/
  */
  div.ExecutionVisualizer {
    /* none for now */
    font-family: Andale mono, monospace;
    overflow: scroll
  }

  div.ExecutionVisualizer input {
    color: #006;
  }
  
  div.ExecutionVisualizer .varLengthInput {
    font-family: Andale mono, monospace;
    font-size: 14pt;
    color: #006;
    display: inline-block;
    width: 70px;
    min-width: 70px;
    height: 100%;
    border: none;
    border-bottom: solid black 1px;
    background: none;
  }

  div.ExecutionVisualizer .sequenceElt .varLengthInput {
    width: 30px;
    min-width: 30px;
  }

  div.ExecutionVisualizer .frameParentHeader {
    font-size: 14pt;
    width: 90px;
    min-width: 90px;
    border: none;
    height: 100%;
    border-bottom: solid black 1px;
    background: none;
  }

  div.ExecutionVisualizer .stackFrame label {
    display: inline;
  }

  div.ExecutionVisualizer .sequenceTypeInput {
    width: 70px;
    min-width: 70px;
  }

  div.ExecutionVisualizer .removeButton {
    display: inline-block;
    background: none;
      border: none;
      padding: 0;
    /* icon is from bootstap icons, licensed under MIT license */
    color: #333333;
    background-image: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" fill="black" class="bi bi-trash-fill" viewBox="0 0 16 16"><path d="M2.5 1a1 1 0 0 0-1 1v1a1 1 0 0 0 1 1H3v9a2 2 0 0 0 2 2h6a2 2 0 0 0 2-2V4h.5a1 1 0 0 0 1-1V2a1 1 0 0 0-1-1H10a1 1 0 0 0-1-1H7a1 1 0 0 0-1 1zm3 4a.5.5 0 0 1 .5.5v7a.5.5 0 0 1-1 0v-7a.5.5 0 0 1 .5-.5M8 5a.5.5 0 0 1 .5.5v7a.5.5 0 0 1-1 0v-7A.5.5 0 0 1 8 5m3 .5v7a.5.5 0 0 1-1 0v-7a.5.5 0 0 1 1 0"/></svg>');
    width: 16px;
    height: 16px;
    background-repeat: no-repeat;
    background-position: center center;
    opacity: 0;
  }
  
  div.ExecutionVisualizer .removeButton:hover,
  div.ExecutionVisualizer .removeButton:focus-visible {
    background-image: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" fill="red" class="bi bi-trash-fill" viewBox="0 0 16 16"><path d="M2.5 1a1 1 0 0 0-1 1v1a1 1 0 0 0 1 1H3v9a2 2 0 0 0 2 2h6a2 2 0 0 0 2-2V4h.5a1 1 0 0 0 1-1V2a1 1 0 0 0-1-1H10a1 1 0 0 0-1-1H7a1 1 0 0 0-1 1zm3 4a.5.5 0 0 1 .5.5v7a.5.5 0 0 1-1 0v-7a.5.5 0 0 1 .5-.5M8 5a.5.5 0 0 1 .5.5v7a.5.5 0 0 1-1 0v-7A.5.5 0 0 1 8 5m3 .5v7a.5.5 0 0 1-1 0v-7a.5.5 0 0 1 1 0"/></svg>');
    cursor: pointer;
    opacity: 100%;
  }


  div.ExecutionVisualizer .removablePrimary:hover .removeButtonPrimary,
  div.ExecutionVisualizer .removableSecondary:hover .removeButtonSecondary,
  div.ExecutionVisualizer .removablePrimary:focus-within .removeButtonPrimary,
  div.ExecutionVisualizer .removableSecondary:focus-within .removeButtonSecondary
  {
    opacity: 100%;
  }

  div.ExecutionVisualizer .addButton {
    display: block;
    background: none;
      border: none;
      padding: 0;
    /* icon is from bootstap icons, licensed under MIT license */
    background-image: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" fill="black" class="bi bi-plus-square-fill" viewBox="0 0 16 16"><path d="M2 0a2 2 0 0 0-2 2v12a2 2 0 0 0 2 2h12a2 2 0 0 0 2-2V2a2 2 0 0 0-2-2zm6.5 4.5v3h3a.5.5 0 0 1 0 1h-3v3a.5.5 0 0 1-1 0v-3h-3a.5.5 0 0 1 0-1h3v-3a.5.5 0 0 1 1 0"/></svg>');
    width: 16px;
    height: 16px;
    background-repeat: no-repeat;
    background-position: center center;
  }

  div.ExecutionVisualizer .addButton:hover,
  div.ExecutionVisualizer .addButton:focus-visible 
  {
    background-image: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" fill="blue" class="bi bi-plus-square-fill" viewBox="0 0 16 16"><path d="M2 0a2 2 0 0 0-2 2v12a2 2 0 0 0 2 2h12a2 2 0 0 0 2-2V2a2 2 0 0 0-2-2zm6.5 4.5v3h3a.5.5 0 0 1 0 1h-3v3a.5.5 0 0 1-1 0v-3h-3a.5.5 0 0 1 0-1h3v-3a.5.5 0 0 1 1 0"/></svg>');    
    cursor: pointer;
  }
  
  div.ExecutionVisualizer table.visualizer {
    font-family: verdana, arial, helvetica, sans-serif;
    font-size: 10pt;
    margin-bottom: 10px;
  }
  
  div.ExecutionVisualizer table.visualizer td.vizLayoutTd {
    vertical-align: top;
  }
  
  div.ExecutionVisualizer td#stack_td,
  div.ExecutionVisualizer td#heap_td {
    vertical-align:top;
    font-size: 10pt; /* don't make fonts in the heap so big! */
  }
  
  div.ExecutionVisualizer #dataViz {
    /*margin-left: 25px;*/
  }
  
  div.ExecutionVisualizer #selectiveHideStatus {
    /*margin-left: 25px;*/
    font-size: 9pt;
    margin-bottom: 15px;
    margin-left: 13px;
  }
  
  /*
  div.ExecutionVisualizer div#codeDisplayDiv {
    width: 550px;
  }
  */
  
  div.ExecutionVisualizer div#pyCodeOutputDiv {
    /*max-width: 550px;*/
    max-height: 460px;
    /*max-height: 620px;*/
    overflow: auto;
    /*margin-bottom: 4px;*/
  
    margin-left: auto;
    margin-right: auto;
  }
  
  div.ExecutionVisualizer table#pyCodeOutput {
    font-family: Andale mono, monospace;
    /*font-size:12pt;*/
    font-size:11pt;
    line-height:1.1em;
  
    border-collapse: separate; /* some crazy CSS voodoo that needs to be
                                  there so that SVG arrows to the left
                                  of the code line up vertically in Chrome */
    border-spacing: 0px;
    border-top: 1px solid #bbb;
    padding-top: 3px;
    border-bottom: 1px solid #bbb;
    /*margin-top: 6px;*/
    margin: 6px auto; /* Center code in its pane */
  }
  
  /* don't wrap lines within code output ... FORCE scrollbars to appear */
  div.ExecutionVisualizer table#pyCodeOutput td {
    white-space: nowrap;
    vertical-align: middle; /* explicitly force, to override external CSS conflicts */
  }
  
  div.ExecutionVisualizer #leftCodeGutterSVG {
    width: 18px;
    min-width: 18px; /* make sure it doesn't squash too thin */
    height: 0px; /* programmatically set this later ... IE needs this to
                    be 0 or it defaults to something arbitrary and gross */
  }
  
  div.ExecutionVisualizer #prevLegendArrowSVG,
  div.ExecutionVisualizer #curLegendArrowSVG {
    width: 18px;
    height: 10px;
  }
  
  div.ExecutionVisualizer .arrow {
    font-size: 16pt;
  }
  
  div.ExecutionVisualizer table#pyCodeOutput .lineNo {
    color: #aaa;
    padding: 0.2em;
    padding-left: 0.3em;
    padding-right: 0.5em;
    text-align: right;
  }
  
  div.ExecutionVisualizer table#pyCodeOutput .cod {
    /*font-weight: bold;*/
    margin-left: 3px;
    padding-left: 7px;
    text-align: left; /* necessary or else doesn't work properly in IE */
  }
  
  div.ExecutionVisualizer div#progOutputs {
    margin-left: 13px; /* line up with heap visualizations */
    margin-bottom: 3px;
  }
  
  div.ExecutionVisualizer div#legendDiv {
    padding: 0px;
    text-align: left;
    color: #666;
    font-size: 9pt;
  }
  
  div.ExecutionVisualizer div#editCodeLinkDiv {
    text-align: center;
    /*
    margin-top: 12px;
    margin-bottom: 4px;
    */
    margin: 8px auto;
    font-size: 11pt;
  }
  
  div.ExecutionVisualizer div#annotateLinkDiv {
    /*text-align: left;*/
    margin-top: 0px;
    margin-bottom: 12px;
    /*
    margin-left: auto;
    margin-right: auto;
    */
  }
  
  div.ExecutionVisualizer div#stepAnnotationDiv {
    margin-bottom: 12px;
  }
  
  div.ExecutionVisualizer textarea#stepAnnotationEditor,
  div.ExecutionVisualizer textarea#vizTitleEditor,
  div.ExecutionVisualizer textarea#vizDescriptionEditor {
    border: 1px solid #999999;
    padding: 4px;
  
    overflow: auto; /* to look pretty on IE */
    /* make sure textarea doesn't grow and stretch */
    resize: none;
  }
  
  
  div.ExecutionVisualizer #errorOutput {
    color: #e93f34; /* should match brightRed JavaScript variable */
    font-size: 11pt;
    padding-top: 2px;
    line-height: 1.5em;
    margin-bottom: 4px;
  }
  
  /* VCR control buttons for stepping through execution */
  
  div.ExecutionVisualizer #vcrControls {
    margin-top: 15px;
    margin-bottom: 6px;
    /*width: 100%;*/
    text-align: center;
  }
  
  div.ExecutionVisualizer #vcrControls button {
    margin-left: 2px;
    margin-right: 2px;
  }
  
  div.ExecutionVisualizer #curInstr {
    text-align: center;
  }
  
  div.ExecutionVisualizer #pyStdout {
    border: 1px solid #999999;
    font-size: 10pt;
    padding: 3px;
    font-family: Andale mono, monospace;
  
    overflow: auto; /* to look pretty on IE */
    /* make sure textarea doesn't grow and stretch */
    resize: none;
  }
  
  
  div.ExecutionVisualizer .vizFrame {
    margin-bottom: 20px;
    padding-left: 8px;
    border-left: 2px solid #cccccc;
  }
  
  
  /* Rendering of primitive types */
  
  div.ExecutionVisualizer .importedObj {
    font-size: 8pt;
  }
  
  div.ExecutionVisualizer .nullObj {
  /*  font-size: 8pt; */
  }
  
  div.ExecutionVisualizer .stringObj,
  div.ExecutionVisualizer .customObj,
  div.ExecutionVisualizer .funcObj {
    font-family: Andale mono, monospace;
    white-space: nowrap;
  }
  
  div.ExecutionVisualizer .funcCode {
    font-size: 8pt;
  }
  
  div.ExecutionVisualizer .retval {
    font-size: 9pt;
  }
  
  div.ExecutionVisualizer .stackFrame .retval {
    color: #e93f34; /* highlight non-zombie stack frame return values -
                       should match brightRed JavaScript variable */
  }
  
  /* Rendering of basic compound types */
  

  div.ExecutionVisualizer table.setTbl,
  div.ExecutionVisualizer .sequenceElt {
    background-color: #ffffc6;
  }
  
  
  div.ExecutionVisualizer .sequence {
    border: 0px solid black;
    border-spacing: 0px;
  }
  
  div.ExecutionVisualizer .sequenceHeader{
    padding-left: 4px;
    padding-top: 2px;
    padding-bottom: 3px;
    font-size: 8pt;
    color: #777;
    text-align: left;
  }
  
  div.ExecutionVisualizer table.tupleTbl {
    border-spacing: 0px;
    color: black;
  
    border-bottom: 1px solid #555555; /* must match td.tupleHeader border */
    border-top: 1px solid #555555; /* must match td.tupleHeader border */
    border-right: 1px solid #555555; /* must match td.tupleHeader border */
  }
  
  
  div.ExecutionVisualizer table.listTbl td.listElt,
  div.ExecutionVisualizer .sequence .sequenceElt
   {
    border-bottom: 1px solid #555555; /* must match td.listHeader border */
    border-left: 1px solid #555555; /* must match td.listHeader border */
  }
  
  
  /* for C and C++ visualizations */
  
  /* make this slightly more compact than listTbl since arrays can be
     rendered on the stack so we want to kinda conserve space */
  div.ExecutionVisualizer table.cArrayTbl {
    background-color: #ffffc6;
    padding-left: 0px;
    padding-top: 0px;
    padding-bottom: 0px;
    font-size: 8pt;
    color: #777;
    text-align: left;
    border: 0px solid black;
    border-spacing: 0px;
  }
  
  div.ExecutionVisualizer table.cArrayTbl td.cArrayHeader {
    padding-left: 5px;
    padding-top: 0px;
    padding-bottom: 2px;
    font-size: 6pt;
    color: #777;
    text-align: left;
    border-bottom: 0px solid black; /* override whatever we're nested in */
  }
  
  div.ExecutionVisualizer table.cArrayTbl td.cArrayElt {
    border-bottom: 1px solid #888;
    border-left: 1px solid #888;
    border-top: 0px solid black;
    color: black;
  
    padding-top: 2px;
    padding-bottom: 4px;
    padding-left: 5px;
    padding-right: 4px;
    vertical-align: bottom;
  }
  
  div.ExecutionVisualizer table.cArrayTbl td.cMultidimArrayHeader {
    padding-left: 5px;
    padding-right: 5px;
    padding-top: 1px;
    padding-bottom: 3px;
    font-size: 6pt;
    color: #777;
    text-align: left;
    border-top: 1px solid #888;
    border-left: 1px solid #888;
    border-bottom: 0px solid black; /* override whatever we're nested in */
  }
  
  div.ExecutionVisualizer table.cArrayTbl td.cMultidimArrayElt {
    border-left: 1px solid #888;
    color: black;
    padding-top: 1px;
    padding-bottom: 4px;
    padding-left: 5px;
    padding-right: 5px;
    vertical-align: bottom;
  }
  
  
  div.ExecutionVisualizer .cdataHeader {
    font-size: 6pt;
    color: #555;
    padding-bottom: 2px;
  }
  
  div.ExecutionVisualizer .cdataElt {
    font-size: 10pt;
  }
  
  div.ExecutionVisualizer .cdataUninit {
    color: #888;
  }
  
  
  div.ExecutionVisualizer table.tupleTbl td.tupleElt {
    border-left: 1px solid #555555; /* must match td.tupleHeader border */
  }
  
  div.ExecutionVisualizer table.customObjTbl {
    background-color: white;
    color: black;
    border: 1px solid black;
  }
  
  div.ExecutionVisualizer table.customObjTbl td.customObjElt {
    padding: 5px;
    font-size: 9pt; /* make this smaller */
  }
  
  div.ExecutionVisualizer .sequence .sequenceElt {
    /* padding-top: 0px;
    padding-bottom: 8px;
    padding-left: 10px;
    padding-right: 10px; */
    vertical-align: bottom;
    display: inline-block;
    position: relative;
  }
  
  div.ExecutionVisualizer table.setTbl {
    border: 1px solid #555555;
    border-spacing: 0px;
    text-align: center;
  }
  
  div.ExecutionVisualizer table.setTbl td.setElt {
    padding: 8px;
  }
  
  
  div.ExecutionVisualizer table.dictTbl,
  div.ExecutionVisualizer table.instTbl,
  div.ExecutionVisualizer table.classTbl {
    border-spacing: 1px;
  }
  
  div.ExecutionVisualizer table.dictTbl td.dictKey,
  div.ExecutionVisualizer table.instTbl td.instKey,
  div.ExecutionVisualizer table.classTbl td.classKey {
    background-color: #faebbf;
  }
  
  div.ExecutionVisualizer table.dictTbl td.dictVal,
  div.ExecutionVisualizer table.instTbl td.instVal,
  div.ExecutionVisualizer table.classTbl td.classVal,
  div.ExecutionVisualizer td.funcCod {
    background-color: #ffffc6;
  }
  
  
  div.ExecutionVisualizer table.dictTbl td.dictKey,
  div.ExecutionVisualizer table.instTbl td.instKey,
  div.ExecutionVisualizer table.classTbl td.classKey {
    padding-top: 6px /*15px*/;
    padding-bottom: 6px;
    padding-left: 10px;
    padding-right: 4px;
  
    text-align: right;
  }
  
  div.ExecutionVisualizer table.dictTbl td.dictVal,
  div.ExecutionVisualizer table.instTbl td.instVal,
  div.ExecutionVisualizer table.classTbl td.classVal {
    padding-top: 6px; /*15px*/;
    padding-bottom: 6px;
    padding-right: 10px;
    padding-left: 4px;
  }
  
  div.ExecutionVisualizer td.funcCod {
    padding-left: 4px;
  }
  
  div.ExecutionVisualizer table.classTbl td,
  div.ExecutionVisualizer table.instTbl td {
    border-bottom: 1px #888 solid;
  }
  
  div.ExecutionVisualizer table.classTbl td.classVal,
  div.ExecutionVisualizer table.instTbl td.instVal {
    border-left: 1px #888 solid;
  }
  
  div.ExecutionVisualizer table.classTbl,
  div.ExecutionVisualizer table.funcTbl {
    border-collapse: collapse;
    border: 1px #888 solid;
  }
  
  /* only add a border to dicts if they're embedded within another object */
  div.ExecutionVisualizer td.listElt table.dictTbl,
  div.ExecutionVisualizer td.tupleElt table.dictTbl,
  div.ExecutionVisualizer td.dictVal table.dictTbl,
  div.ExecutionVisualizer td.instVal table.dictTbl,
  div.ExecutionVisualizer td.classVal table.dictTbl {
    border: 1px #888 solid;
  }
  
  div.ExecutionVisualizer .objectIdLabel {
    font-size: 8pt;
    color: #444;
    margin-bottom: 2px;
  }

  div.ExecutionVisualizer .heapObjectHeader {
    white-space: nowrap;
  }
  
  div.ExecutionVisualizer .typeLabel {
    display: inline;
    font-size: 8pt;
    color: #555;
    margin-bottom: 2px;
  }
  
  div.ExecutionVisualizer div#stack,
  div.ExecutionVisualizer div#globals_area {
    padding-left: 10px;
    padding-right: 30px;
  
    /* no longer necessary ... */
    /*float: left;*/
    /* border-right: 1px dashed #bbbbbb; */
  }
  
  div.ExecutionVisualizer div.stackFrame,
  div.ExecutionVisualizer div.zombieStackFrame {
    background-color: #e2ebf6;
    margin-bottom: 15px;
    padding: 2px;
    padding-left: 6px;
    padding-right: 6px;
    padding-bottom: 4px;
    font-size: 10pt;
    white-space: nowrap;
  }
  
  div.ExecutionVisualizer div.zombieStackFrame {
    border-left: 1px dotted #aaa;
    /*color: #c0c0c0;*/
    color: #a0a0a0;
  }
  
  div.ExecutionVisualizer div.highlightedStackFrame {
    background-color: #e2ebf6;
    /*background-color: #d7e7fb;*/
  
    /*background-color: #c0daf8;*/
    /*background-color: #9eeaff #c5dfea;*/
  }
  
  div.ExecutionVisualizer div.stackFrame,
  div.ExecutionVisualizer div.highlightedStackFrame {
    border-left: 1px solid #a6b3b6;
  }
  
  
  div.ExecutionVisualizer div.stackFrameHeader {
    font-family: Andale mono, monospace;
    font-size: 10pt;
    margin-top: 4px;
    margin-bottom: 3px;
    white-space: nowrap;
  }
  
  div.ExecutionVisualizer td.stackFrameVar {
    text-align: right;
    padding-right: 8px;
    padding-top: 3px;
    padding-bottom: 3px;
    border-bottom: 1px solid #aaaaaa;
  }
  
  div.ExecutionVisualizer td.stackFrameVar input {
    text-align: right;
    background: none;
    border: none;
  }
  
  div.ExecutionVisualizer td.stackFrameValue {
    text-align: left;
    border-bottom: 1px solid #aaaaaa;
    border-left: 1px solid #aaaaaa;
    
    padding-top: 0px;
    padding-left: 0px;
    padding-bottom: 0px;
  }
  
  div.ExecutionVisualizer .stackFrameVarTable {
    text-align: right;
    padding-top: 3px;
    border-spacing: 10px;
    white-space:nowrap;
  
    /* right-align the table */
    margin-left: auto;
    margin-right: 0px;
    width: 100%;
  
    /* hack to counteract possible nasty CSS reset styles from parent divs */
    border-collapse: separate;
  }
  
  div.ExecutionVisualizer div#heap {
    padding-left: 30px;
  }
  
  div.ExecutionVisualizer div.topLevelHeapObject {
    /* needed for d3 to do transitions */
    padding-left: 8px;
    padding-right: 8px;
    padding-top: 10px;
    padding-bottom: 10px;
    background: aliceblue;
    border: 1px black solid;
    border-radius: 3px;
    width: min-content;
    z-index: 20;
    position: relative;
    margin-bottom: 10px;
  }
  
  div.ExecutionVisualizer div.heapObject {
    display: inline-block;
    padding-left: 2px; /* leave a TINY amount of room for connector endpoints */
    z-index: 50;
  }
  
  div.ExecutionVisualizer div.heapPrimitive {
    padding-left: 4px; /* leave some more room for connector endpoints */
  }
  
  div.ExecutionVisualizer div#stackHeader {
    margin-bottom: 15px;
    text-align: right;
  }
  
  div.ExecutionVisualizer div#heapHeader {
    /*margin-top: 2px;
    margin-bottom: 13px;*/
    margin-bottom: 15px;
  }
  
  div.ExecutionVisualizer div#stackHeader,
  div.ExecutionVisualizer div#heapHeader {
    color: #333333;
    font-size: 10pt;
  }
  
  div.ExecutionVisualizer div#langDisplayDiv {
    text-align: center;
    margin-top: 2pt;
    margin-bottom: 3pt;
    font-size: 9pt;
  }
  
  div.ExecutionVisualizer #executionSlider {
    /* if you set 'width', then it looks ugly when you dynamically resize */
    margin-top: 15px;
    margin-bottom: 5px;
  
    /* DON'T center this, since we need breakpoints in executionSliderFooter to be well aligned */
    width: 98%;
  }
  
  div.ExecutionVisualizer #executionSliderCaption {
    font-size: 8pt;
    color: #666666;
    margin-top: 15px;
  }
  
  div.ExecutionVisualizer #executionSliderFooter {
    margin-top: -7px; /* make it butt up against #executionSlider */
  }
  
  div.ExecutionVisualizer #codeFooterDocs,
  div.ExecutionVisualizer #printOutputDocs {
    margin-bottom: 3px;
    font-size: 8pt;
    color: #666;
  }
  
  div.ExecutionVisualizer #codeFooterDocs {
    margin-top: 5px;
    margin-bottom: 12px;
    width: 95%;
  }
  
  /* darken slider handle a bit */
  div.ExecutionVisualizer .ui-slider .ui-slider-handle {
    border: 1px solid #999;
  }
  
  
  /* for annotation bubbles */
  
  /* For styling tricks, see: http://css-tricks.com/textarea-tricks/ */
  textarea.bubbleInputText {
    border: 1px solid #ccc;
    outline: none;
    overflow: auto; /* to look pretty on IE */
  
    /* make sure textarea doesn't grow and stretch the enclosing bubble */
    resize: none;
    width: 225px;
    max-width: 225px;
    height: 35px;
    max-height: 35px;
  }
  
  div.ExecutionVisualizer .annotationText,
  div.ExecutionVisualizer .vizDescriptionText {
    font-family: verdana, arial, helvetica, sans-serif;
    font-size: 11pt;
    line-height: 1.5em;
  }
  
  div.ExecutionVisualizer .vizTitleText {
    font-family: verdana, arial, helvetica, sans-serif;
    font-size: 16pt;
    margin-bottom: 12pt;
  }
  
  div.ExecutionVisualizer div#vizHeader {
    margin-bottom: 10px;
    width: 700px;
    max-width: 700px;
  }
  
  /* prev then curr, so curr gets precedence when both apply */
  div.ExecutionVisualizer .highlight-prev {
    background-color: #F0F0EA;
  }
  
  div.ExecutionVisualizer .highlight-cur {
    background-color: #FFFF66;
  }
  
  div.ExecutionVisualizer .highlight-legend {
    padding: 2px;
  }
  
  /* resizing sliders from David Pritchard */
  .ui-resizable-e {
    background-color: #dddddd;
    width: 1px;
    border: 3px solid white;
  }
  
  .ui-resizable-e:hover {
    border-color: #dddddd;
  }
  
  div.ExecutionVisualizer a,
  div.ExecutionVisualizer a:visited,
  div.ExecutionVisualizer a:hover {
    color: #3D58A2;
  }
  
  div.ExecutionVisualizer div#rawUserInputDiv {
    padding: 5px;
    width: 95%;
    margin: 5px auto;
    text-align: center;
    border: 1px #e93f34 solid;
  }
  
  /* for pyCrazyMode */
  
  /* prev then curr, so curr gets precedence when both apply */
  div.ExecutionVisualizer .pycrazy-highlight-prev {
    background-color: #eeeeee; /*#F0F0EA;*/
    /*
    text-decoration: none;
    border-bottom: 1px solid #dddddd;
    */
  }
  
  div.ExecutionVisualizer .pycrazy-highlight-cur {
    background-color: #FFFF66;
    /* aligned slightly higher than border-bottom */
    /*
    text-decoration: none;
    border-bottom: 1px solid #e93f34;
    */
  }
  
  div.ExecutionVisualizer .pycrazy-highlight-prev-and-cur {
    background-color: #FFFF66;
  
    text-decoration: none;
    border-bottom: 1px solid #999999;
  }
  
  
  #optTabularView thead.stepTableThead {
    background-color: #bbb;
  }
  
  #optTabularView tbody.stepTableTbody {
  }
  
  #optTabularView td.stepTableTd {
    padding: 3px 10px;
  }
  
  #uiControlsPane {
    font-size: 8pt;
  }
  
  
  /* BEGIN Java frontend by David Pritchard and Will Gwozdz */
  
  /* stack and queue css by Will Gwozdz */
  div.ExecutionVisualizer table.queueTbl,
  div.ExecutionVisualizer table.stackTbl {
    background-color: #ffffc6;
  }
  
  div.ExecutionVisualizer table.queueTbl,
  div.ExecutionVisualizer table.stackTbl {
    border: 0px solid black;
    border-spacing: 0px;
  }
  
  div.ExecutionVisualizer table.stackTbl td.stackElt,
  div.ExecutionVisualizer table.queueTbl td.queueElt {
    padding-left: 8px;
    padding-right: 8px;
    padding-top: 2px;
    padding-bottom: 3px;
    border-top: 1px solid #555555;
    border-bottom: 1px solid #555555;
    border-left: 1px dashed #555555;
  }
  
  div.ExecutionVisualizer table.stackTbl td.stackFElt,
  div.ExecutionVisualizer table.queueTbl td.queueFElt {
    background-color: white;
    border-top: 1px solid #555555;
    border-bottom: 1px solid #555555;
  }
  
  div.ExecutionVisualizer table.stackTbl td.stackLElt {
    background-color: white;
    border-left: 1px solid #555555;
  }
  
  div.ExecutionVisualizer table.queueTbl td.queueLElt {
    background-color: white;
    border-top: 1px solid#555555;
    border-bottom: 1px solid #555555;
    border-left: 1px dashed #555555;
  }
  
  /* This ensures a border is drawn around a dict
     if its nested in another object. */
  div.ExecutionVisualizer td.stackElt table.dictTbl,
  div.ExecutionVisualizer td.stackLElt table.dictTbl,
  div.ExecutionVisualizer td.stackFElt table.dictTbl,
  div.ExecutionVisualizer td.queueElt table.dictTbl,
  div.ExecutionVisualizer td.queueLElt table.dictTbl,
  div.ExecutionVisualizer td.queueFElt table.dictTbl {
    border: 1px #888 solid;
  }
  
  .symbolic {
    font-size: 18pt;
  }
  
  /* END Java frontend by David Pritchard and Will Gwozdz */
  div.ExecutionVisualizer .vizLayoutTd {
    display: block;
    position: relative;
  }

  div.ExecutionVisualizer .pointerArrowHeadDefSvg {
    width: 0px;
    height: 0px;
  }

  div.ExecutionVisualizer .pointerArrow svg {
    display: block;
    position: absolute;
    pointer-events:none;
    overflow: visible;
    z-index: 1000;
  }

  div.ExecutionVisualizer .pointerArrow path {
    stroke: black;
    stroke-width: 1px;
    fill: none;
  }

  div.ExecutionVisualizer .pointerArrowTentative path {
    stroke-dasharray: 2px;
  }

  div.ExecutionVisualizer .pointerArrow input {
    display: none;
  }

  div.ExecutionVisualizer .connectButton {
    position: absolute;
    background: transparent;
    border-radius: 10em;
    width: 5px;
    height: 5px;
    padding: 0;
    left: 2px;
    top: calc(50% - 3px);
    display: none;
  }
  div.ExecutionVisualizer .valueContainer {
    display: flex;
    flex-direction: row;
    flex-wrap: nowrap;
    justify-content: space-between;
    align-items: flex-end;
    width: 100%
  }

  div.ExecutionVisualizer .valueContainer > input {
    background: none;
    border: none;
    margin-top: 3px;
    margin-left: 3px;
    margin-bottom: 3px;
    flex-grow: 1;
  }

  div.ExecutionVisualizer .valueContainer .varLengthInputPointer {
    min-width: 0px !important;
    visibility: hidden;
  }

  div.ExecutionVisualizer .pointerValueButton {
    display: inline;
    background: none;
      border: 1px solid #333333;
      color: #333333;
      padding: 0;
    /* icon is from bootstap icons, licensed under MIT license */
    width: 16px;
    height: 16px;
    background-repeat: no-repeat;
    background-position: center center;
    background-size: contain;
    opacity: 0;
  }

  div.ExecutionVisualizer .valueContainer:hover .pointerValueButton,
  div.ExecutionVisualizer .valueContainer:focus-within .pointerValueButton {
    opacity: 100%;
  }

  div.ExecutionVisualizer .pointerButton {
        background-image: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" fill="currentColor" class="bi bi-arrow-up-right" viewBox="0 0 16 16"><path fill-rule="evenodd" d="M14 2.5a.5.5 0 0 0-.5-.5h-6a.5.5 0 0 0 0 1h4.793L2.146 13.146a.5.5 0 0 0 .708.708L13 3.707V8.5a.5.5 0 0 0 1 0z"/></svg>');
  }

  div.ExecutionVisualizer .valueButton {
    background-image: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" fill="currentColor" class="bi bi-fonts" viewBox="0 0 16 16"><path d="M12.258 3h-8.51l-.083 2.46h.479c.26-1.544.758-1.783 2.693-1.845l.424-.013v7.827c0 .663-.144.82-1.3.923v.52h4.082v-.52c-1.162-.103-1.306-.26-1.306-.923V3.602l.431.013c1.934.062 2.434.301 2.693 1.846h.479z"/></svg>');

  }

  div.ExecutionVisualizer .pointerValueButton:hover {
    cursor: pointer;
  }

  div.ExecutionVisualizer .pointerInput {
    display: none;
  }

  @media (hover: none) {
    div.ExecutionVisualizer button .btn {
      opacity: 1 !important;
    }
  }

  .ExecutionVisualizerInactive input {
    pointer-events:none !important;
  }
  
  .ExecutionVisualizerInactive button {
    visibility: hidden !important; 
    pointer-events:none !important;
  }

  div.ExecutionVisualizer .sequenceElt,
  div.ExecutionVisualizer .sequenceContent, 
  div.ExecutionVisualizer .sequence {
    position: relative;
  }

  div.ExecutionVisualizer .sequenceContent {
    white-space: nowrap;
    display: flex;
    flex-direction: row;
    flex-wrap: nowrap;
  }

  div.ExecutionVisualizer .sequenceElementValueContainer {
    text-align: right;
  }

  div.ExecutionVisualizer .sequenceAddButtonContainer {
    opacity: 0;
    display: inline-block;
  }

  div.ExecutionVisualizer .topLevelHeapObject:hover .sequenceAddButtonContainer,
  div.ExecutionVisualizer .topLevelHeapObject:focus-within .sequenceAddButtonContainer {
    opacity: 1
  }
/* Now for the stuff relevant to add buttons when lists are non=empty */

  div.ExecutionVisualizer .sequenceElt .sequenceAddButtonContainer {
    position: absolute;
  }

  div.ExecutionVisualizer .sequenceElt .sequencePrependButtonContainer {
    top: 20px;
    left: -8px;
  }
  
  div.ExecutionVisualizer .sequenceElt .sequenceAddButtonContainer > button {
    opacity: 0;
    /* margin-top: 25px;
    margin-left: auto;
    margin-right: auto; */
  }

  div.ExecutionVisualizer .sequenceElt:hover .sequenceAddButtonContainer > button, 
  div.ExecutionVisualizer .sequenceElt .sequenceAddButtonContainer > button:focus-visible,
  div.ExecutionVisualizer .sequenceElt:hover + .sequenceElt > .sequencePrependButtonContainer > button, 
  div.ExecutionVisualizer .sequenceElt .sequenceAddButtonContainer:hover > button
  {
    opacity: 1;
  }

  div.ExecutionVisualizer .sequenceElt:first-child .sequencePrependButtonContainer, 
  div.ExecutionVisualizer .sequenceElt:last-child .sequenceAppendButtonContainer {
    height: 100%;
    width: 15px;
    position: absolute;
    top: 0px;
    z-index: 35;
  }

  div.ExecutionVisualizer .sequenceElt:first-child .sequencePrependButtonContainer{
    left: -15px;
  }

  div.ExecutionVisualizer .sequenceElt:last-child .sequenceAppendButtonContainer {
    right: -15px;
  }

  div.ExecutionVisualizer .sequenceElt:first-child .sequencePrependButtonContainer > button, 
  div.ExecutionVisualizer .sequenceElt:last-child .sequenceAppendButtonContainer > button {
    position: absolute;
    top: 20px;
  }

  div.ExecutionVisualizer .sequenceElt:first-child .sequencePrependButtonContainer > button {
    right: -50%;
  }

  div.ExecutionVisualizer .sequenceElt:last-child .sequenceAppendButtonContainer > button {
    left: -50%;
  }

  div.ExecutionVisualizer .sequenceElt .sequenceAddButtonContainer:hover > button, 
  div.ExecutionVisualizer .sequenceElt .sequenceAddButtonContainer > button:focus-visible {
    opacity: 100%;
  }