styles.css

/* Style for hint question block. */
details.stack-hint {
    padding: 2px;
    display: block;
    border: 1px solid #ccc;
    background-color: #f2f2f2;
    width: fit-content;
}

div.stack-hint-content {
    padding: 10px;
}

/* Styles used when questions are being attempted. */
.que.stack .stackruntimeerrror {
    color: #c02200;
    font-size: 100%;
    font-weight: bold;
}
.que.stack .stacksyntaxexample {
    color: #1f536b;
    font-family: monospace;
    font-size: 100%;
    font-weight: bold;
}
.que.stack .stacksyntaxexamplehighlight {
    color: #f00;
}
.que.stack .stackinputfeedback.standard {
    border: 1px solid #fff;
    background-color: #fff;
    margin: 0.2em 3em 0.5em;
    padding: 0.5em 0.5em 0;
}
.que.stack .stackinputfeedback.equiv {
    vertical-align: top;
    display: inline-block;
    background-color: #fff;
    margin: 0;
    padding: 0.2em;
}
.que.stack .stackinputfeedback.compact {
    margin: 3px 3px 3px;
    display: inline-block;
    vertical-align: top;
    background-color: white;
    border: 1px solid #ccc;
    padding: 0.3em;
}
.stackinputfeedback .MathJax_Display {
    margin: 0.5em 0;
}
.que.stack .stackinputerror {
    padding: 0.2em 0.2em 0.2em;
    margin: 3px 3px 3px;
    display: block;
}
.que.stack .stackinputnotice {
    font-size: x-small;
    color: #888;
}
.que.stack .stackinputfeedback.empty {
    display: none;
}
.que.stack .stackinputfeedback.waiting,
.que.stack .stackinputfeedback.loading {
    color: #888;
    min-height: 1em;
}
.que.stack .stackinputfeedback.loading {
    background: #fff url([[pix:moodle|i/loading_small]]) no-repeat top right;
}
.que.stack .stackinputfeedback.waiting .stacksyntaxexample,
.que.stack .stackinputfeedback.loading .stacksyntaxexample {
    color: #84aec1;
}
.que.stack textarea {
    vertical-align: top;
    display: inline-block;
    max-width: 100%;
    resize: both;
}
#id_questionvariables,
textarea[id*=feedbackvariables],
textarea[name=maximavars] {
    min-width: 100%;
    font-family: monospace;
}
.que.stack input[type=checkbox] {
    margin-right: 0.4em;
}
.que.stack input[type=radio] {
    margin-right: 0.4em;
}
.que.stack input[type=text] {
    max-width: 100%;
}
.que.stack select.form-select {
    display: inline-block;
}
.que.stack .geogebra-right,
.que.stack .numerical-right,
.que.stack .algebraic-right,
.que.stack .algebraic-units-right {
    max-width: 100%;
    text-align: right;
}
.que.stack .input-monospace {
    font-family: monospace;
}

.que.stack .formulation .stackprtfeedback {
    background: #fcf8e3;
    margin: 0.2em -0.2em 0.5em;
    padding: 0.2em 0.5em 0.2em 0.2em;
    display: inline-block;
    vertical-align: top;
}
.que.stack .formulation .stackprtfeedback .correct,
.que.stack .formulation .stackprtfeedback .partiallycorrect,
.que.stack .formulation .stackprtfeedback .incorrect {
    background: transparent;
    font-weight: 700;
}
.que.stack .formulation .questiontestslink {
    float: right;
    font-size: 0.8em;
    margin: -0.3em -0.3em;
}
body.pagelayout-embedded .que.stack .formulation .questiontestslink {
    display: none;
}

.que.stack .formulation .answer .option {
    margin: 0.7em;
}

.que.stack .matrixtable {
    border-collapse: collapse;
}

.que.stack div.matrixroundbrackets {
    display: inline-block;
    border: 0;
    border-left: 2px solid #000;
    border-right: 2px solid #000;
    border-radius: 1em;
    padding: 0.5em;
}

.que.stack div.matrixnobrackets {
    display: inline-block;
    border: 0;
    padding: 0.5em;
}

.que.stack div.matrixbarbrackets {
    display: inline-block;
    border: 0;
    border-left: 2px solid #000;
    border-right: 2px solid #000;
    padding: 0.5em;
}

.que.stack div.matrixsquarebrackets {
    display: inline-block;
    background-image:
        linear-gradient(#000, #000),
        linear-gradient(#000, #000),
        linear-gradient(#000, #000),
        linear-gradient(#000, #000);
    background-repeat: no-repeat;
    background-size: 8px 2px;
    background-position: top left, top right, bottom left, bottom right;
    border: solid #000;
    border-width: 0 2px;
    padding: 0.5em;
}

.que.stack textarea.varmatrixinput {
    overflow: hidden;
    white-space: pre;
    min-width: 3rem;
    min-height: 3rem;
    width: 3rem;
    height: 3rem;
    outline: none;
    direction: ltr;
    unicode-bidi: plaintext;
}

.que.stack textarea.equivinput {
    overflow: hidden;
    white-space: pre;
    outline: none;
    direction: ltr;
    unicode-bidi: plaintext;
}

body.path-question-type-stack-doc blockquote {
    border-left: 5px solid #ccc;
    margin: 1.5em 10px;
    padding: 1em 10px .1em 10px;
    quotes: "\201C""\201D""\2018""\2019";
}

/* Support for comments, used in example questions. */
div.stack-comment {
    text-align: left;
    background: #fcf8e3;
    border: 4px solid #ddd;
    border-radius: 12px;
    padding: 12px;
    margin: 4px;
    overflow: hidden;
}

/* Support for proof. */
.statement {
    padding: 12px 16px;
    margin: 8px 0;
    border: 1px solid #ddd;
    border-radius: 6px;
    background-color: #fff;
}
.proof,
.proof-block {
    text-align: left;
    background: rgba(255, 255, 255, 0.3);
    border: 1px solid #ddd;
    border-radius: 4px;
    padding: 3px;
    margin: 2px 4px;
    overflow: hidden;
}
.proof-block {
    border: none;
    border-left: 3px solid;
    margin-top: 1em;
    padding-left: 1em;
}

/* Proofs have lines, containing columns.  Clear floats after the columns. */
.proof-line {
    width: 100%;
    content: "";
    display: table;
    clear: both;
}
/* Create columns that floats next to each other. */
.proof-num {
    float: left;
    width: 25px;
    padding: 1px;
}
.proof-comment {
    background: rgba(255, 255, 255, 0.7);
    float: right;
    border-radius: 3px;
    border: 1px solid #ddd;
    padding: 2px;
    margin: 2px;
}
.proof-step,
.proof-column,
.proof-column-2 {
    float: left;
    padding: 1px;
}
/* Proof columns have a fixed width.  Comments and steps do not.  */
.proof-column,
.proof-column-2 {
    width: 48%;
}
.proof-column-2 {
    background: rgba(255, 255, 255, 0.7);
}

@media screen and (max-width: 900px) {
    .proof-column {
        width: 100%;
    }
    .proof-column-2 {
        width: 100%;
    }
}

/* Style some proofs as numbered steps. */
ol.proof-steps {
    counter-reset: li;
    margin-left: 0;
    padding-left: 0;
    margin-top: 0;
}
ol.proof-steps > li {
    position: relative;
    margin-left: 2em;
    padding: 0.5em;
    list-style: none;
    line-height: 1.5em;
}
ol.proof-steps > li > p {
    margin: 0;
}
ol.proof-steps > li:before {
    content: counter(li);
    counter-increment: li;
    position: absolute;
    top: 7px;
    left: -2em;
    -webkit-box-sizing: border-box;
    box-sizing: border-box;
    width: 1.5em;
    height: 1.5em;
    margin-right: .2em;
    margin-top: 0;
    border-style: none;
    border-radius: 50%;
    line-height: 1.4em;
    text-align: center;
    z-index: 2;
    background-color: #039;
    color: white;
    font-weight: 600;
    vertical-align: middle;
    padding-top: 1px;
}

ol.proof-steps > li:after {
    position: absolute;
    left: -19px;
    top: 10px;
    content: "";
    height: 100%;
    width: 0;
    border-left: 3px solid #039;
    z-index: 1;
}
ol.proof-steps > li:last-of-type:after {
    border: none;
}
ol.proof-steps > li:before {
    content: counter(li, decimal);
}
ol.proof-steps ol.proof-steps > li:before {
    content: counter(li, lower-latin);
}
ol.proof-steps ol.proof-steps ol.proof-steps > li:before {
    content: counter(li, lower-roman);
}

/* Styles for the editing form. */
body#page-question-type-stack .fitem_fgroup .accesshide,
body#page-question-type-stack-questiontestedit .fitem_fgroup .accesshide {
    font: inherit;
    left: 0;
    position: static;
}
body#page-question-type-stack div[id^=fgroup_id_][id*=node_] {
    margin-top: 2em;
    background: #ddf;
    margin-bottom: 0;
}
body#page-question-type-stack div[id^=fgroup_id_][id*=nodewhentrue_],
body#page-question-type-stack div[id^=fitem_id_][id*=truefeedback_] {
    background: #cfc;
    margin-bottom: 0;
}
body#page-question-type-stack div[id^=fgroup_id_][id*=nodewhenfalse_],
body#page-question-type-stack div[id^=fitem_id_][id*=falsefeedback_] {
    background: #fcc;
    margin-bottom: 0;
}
body#page-question-type-stack div[id^=fitem_id_][id*=truefeedback_],
body#page-question-type-stack div[id^=fitem_id_][id*=falsefeedback_] {
    padding-bottom: 0.3em;
}
body#page-question-type-stack div[id^=fitem_id_][id*=nodeadd] {
    margin-top: 2em;
}

/* Styles for the supporting scripts, healthcheck, etc. */
body.path-question-type-stack dt {
    font-weight: bold;
}
body.path-question-type-stack dd {
    margin-left: 2em;
}
body#page-question-type-stack-healthcheck textarea {
    font-family: monospace;
    width: 100%;
    white-space: pre;
}
body#page-question-type-stack-healthcheck div.box {
    background: #ddd;
}
body#page-question-type-stack-healthcheck div.box h2 {
    margin-top: 0;
    margin-bottom: 0;
}
body#page-question-type-stack-healthcheck div.box h3 {
    margin-top: 0.7em;
    margin-bottom: 0.3em;
}
body#page-question-type-stack-healthcheck div.box pre {
    margin-bottom: 0;
}
body.path-question-type-stack table.stacktestsuite .notes td,
body.path-question-type-stack p.notes {
    font-weight: bold;
}
body.path-question-type-stack table.stacktestsuite .pass td,
body.path-question-type-stack p.pass {
    background-color: #dfd;
}
body.path-question-type-stack table.stacktestsuite .fail td,
body.path-question-type-stack p.fail {
    background-color: #fdd;
}
body.path-question-type-stack table.stacktestsuite .expectedfail td {
    background-color: #ffd;
}
body.path-question-type-stack table.stacktestsuite pre {
    font-size: 0.8em;
    background: #fff9;
    padding: 0.25rem;
    max-width: 60em;
}
body.path-question-type-stack .stacktestsuite td {
    padding: 0.3rem 0.3rem 0.3rem 0.75rem;
}
body.path-question-type-stack .stacktestsuite .MathJax_Display {
    margin: 0;
}
body.path-question-type-stack .stacktestsuite {
    margin-bottom: 0.5rem;
}
.questionvariables pre {
    white-space: pre-wrap;
}
body.path-question-type-stack h2.fail,
body.path-question-type-stack h3 span.fail {
    color: #f00;
}
body.path-question-type-stack h2.pass,
body.path-question-type-stack h3 span.pass {
    color: #080;
}
body.path-question-type-stack .overallresult {
    color: white;
    font-weight: bold;
    padding: 0.5em;
    border-radius: 5px;
}
body.path-question-type-stack .overallresult.fail {
    background: #f00;
}
body.path-question-type-stack .overallresult.pass {
    background: #080;
}
body.path-question-type-stack .testcasebuttons div,
body.path-question-type-stack .testcasebuttons form {
    display: inline;
}

body.path-question-type-stack pre.questiontext,
body#page-question-type-stack-replacedollars div.questiontext,
body.path-question-type-stack .questionnote,
body.path-question-type-stack .questionvariables {
    background: #eee;
    padding: 1em;
}
body.path-question-type-stack div.questionvariables {
    padding-bottom: 0.1em;
}
body.path-question-type-stack .factsheet {
    color: #000;
    border: 1px solid #000;
    background: #eee;
    padding: 1em;
}

body.path-question-type-stack .undeployedvariant .singlebutton,
body.path-question-type-stack .undeployedvariant .singlebutton div,
body.path-question-type-stack .undeployedvariant .singlebutton form {
    display: inline;
}
body.path-question-type-stack .switchtovariant {
    margin-top: 1em;
}

.displayequation {
    display: block;
    text-align: left;
    margin: 0.5em 0 0.5em 2em;
}
.stack_plot {
    text-align: center;
}
body#page-question-type-stack-replacedollars pre.questiontext {
    white-space: pre-wrap;
}
body#page-question-type-stack-replacedollars pre del {
    color: red;
    font-weight: bold;
}
body#page-question-type-stack-replacedollars pre ins {
    color: green;
    font-weight: bold;
}

body.ie:not(.ie11) .stack_abstract_graph {
    /* Once IE can cope, we can delete this rule. */
    display: none;
}
.stack_abstract_graph {
    background: #ffc;
    margin: 5px;
}
.stack_abstract_graph path {
    stroke-width: 3px;
    fill: none;
}
.stack_abstract_graph path.left {
    stroke: #0d0;
}
.stack_abstract_graph circle.left {
    fill: #0d0;
}
.stack_abstract_graph path.right {
    stroke: #a00;
}
.stack_abstract_graph circle.right {
    fill: #a00;
}
.stack_abstract_graph path.cross {
    stroke: #f00;
    stroke-linecap: round;
}
.stack_abstract_graph text {
    font-family: Verdana, sans-serif;
}
.stack_abstract_graph text.nodelabel {
    font-size: 0.8em;
    fill: #fff;
    alignment-baseline: middle;
    text-anchor: middle;
}
.stack_abstract_graph text.edgelabel {
    font-size: 0.8em;
    fill: #000;
    alignment-baseline: middle;
}
.stack_abstract_graph text.edgelabel.left {
    text-anchor: end;
}
.stack_abstract_graph text.edgelabel.right {
    text-anchor: start;
}
.stack_abstract_graph circle.node {
    fill: #00f;
}

/* This should all be inherited in some way from the theme settings. */
#basic-modal-content {
    display: none;
}

/* Overlay */
#simplemodal-overlay {
    background-color: #000;
    cursor: wait;
}

/* Container */
#simplemodal-container {
    height: 360px;
    width: 600px;
    border: 4px solid #444;
    padding: 12px;
    background-color: inherit;
}
#simplemodal-container .simplemodal-data {
    padding: 8px;
}
#simplemodal-container a.modalCloseImg {
    background: url(./x.png) no-repeat;
    width: 25px;
    height: 29px;
    display: inline;
    z-index: 3200;
    position: absolute;
    top: -15px;
    right: -16px;
    cursor: pointer;
}

/*! jQuery UI - v1.12.1 - 2019-05-02
* http://jqueryui.com
* Includes: core.css, autocomplete.css, menu.css, theme.css
* Copyright jQuery Foundation and other contributors; Licensed MIT */

/* Layout helpers
----------------------------------*/
.ui-helper-hidden {
    display: none;
}
.ui-helper-hidden-accessible {
    border: 0;
    clip: rect(0 0 0 0);
    height: 1px;
    margin: -1px;
    overflow: hidden;
    padding: 0;
    position: absolute;
    width: 1px;
}
.ui-helper-reset {
    margin: 0;
    padding: 0;
    border: 0;
    outline: 0;
    line-height: 1.3;
    text-decoration: none;
    font-size: 100%;
    list-style: none;
}
.ui-helper-clearfix:before,
.ui-helper-clearfix:after {
    content: "";
    display: table;
    border-collapse: collapse;
}
.ui-helper-clearfix:after {
    clear: both;
}
.ui-helper-zfix {
    width: 100%;
    height: 100%;
    top: 0;
    left: 0;
    position: absolute;
    opacity: 0;
}

.ui-front {
    z-index: 100;
}

/* Interaction Cues
----------------------------------*/
.ui-state-disabled {
    pointer-events: none;
}

/* Icons
----------------------------------*/
.ui-icon {
    display: inline-block;
    vertical-align: middle;
    margin-top: -.25em;
    position: relative;
    text-indent: -99999px;
    overflow: hidden;
    background-repeat: no-repeat;
}

.ui-widget-icon-block {
    left: 50%;
    margin-left: -8px;
    display: block;
}

/* Misc visuals
----------------------------------*/

/* Overlays */
.ui-widget-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
}
.ui-autocomplete {
    position: absolute;
    top: 0;
    left: 0;
    cursor: default;
}
.ui-menu {
    list-style: none;
    padding: 0;
    margin: 0;
    display: block;
    outline: 0;
}
.ui-menu .ui-menu {
    position: absolute;
}
.ui-menu .ui-menu-item {
    margin: 0;
    cursor: pointer;
}
.ui-menu .ui-menu-item-wrapper {
    position: relative;
    padding: 3px 1em 3px .4em;
}
.ui-menu .ui-menu-divider {
    margin: 5px 0;
    height: 0;
    font-size: 0;
    line-height: 0;
    border-width: 1px 0 0 0;
}
.ui-menu .ui-state-focus,
.ui-menu .ui-state-active {
    margin: -1px;
}

/* icon support */
.ui-menu-icons {
    position: relative;
}
.ui-menu-icons .ui-menu-item-wrapper {
    padding-left: 2em;
}

/* left-aligned */
.ui-menu .ui-icon {
    position: absolute;
    top: 0;
    bottom: 0;
    left: .2em;
    margin: auto 0;
}

/* right-aligned */
.ui-menu .ui-menu-icon {
    left: auto;
    right: 0;
}

/* Component containers
----------------------------------*/
.ui-widget {
    font-family: Arial, Helvetica, sans-serif;
    font-size: 1em;
}
.ui-widget .ui-widget {
    font-size: 1em;
}
.ui-widget input,
.ui-widget select,
.ui-widget textarea,
.ui-widget button {
    font-family: Arial, Helvetica, sans-serif;
    font-size: 1em;
}
.ui-widget.ui-widget-content {
    border: 1px solid #c5c5c5;
}
.ui-widget-content {
    border: 1px solid #ddd;
    background: #fff;
    color: #333;
}
.ui-widget-content a {
    color: #333;
}
.ui-widget-header {
    border: 1px solid #ddd;
    background: #e9e9e9;
    color: #333;
    font-weight: bold;
}
.ui-widget-header a {
    color: #333;
}

/* Interaction states
----------------------------------*/
.ui-state-default,
.ui-widget-content .ui-state-default,
.ui-widget-header .ui-state-default,
.ui-button,
/* We use html here because we need a greater specificity to make sure disabled works properly when clicked or hovered */
html .ui-button.ui-state-disabled:hover,
html .ui-button.ui-state-disabled:active {
    border: 1px solid #c5c5c5;
    background: #f6f6f6;
    font-weight: normal;
    color: #454545;
}
.ui-state-default a,
.ui-state-default a:link,
.ui-state-default a:visited,
a.ui-button,
a:link.ui-button,
a:visited.ui-button,
.ui-button {
    color: #454545;
    text-decoration: none;
}
.ui-state-hover,
.ui-widget-content .ui-state-hover,
.ui-widget-header .ui-state-hover,
.ui-state-focus,
.ui-widget-content .ui-state-focus,
.ui-widget-header .ui-state-focus,
.ui-button:hover,
.ui-button:focus {
    border: 1px solid #ccc;
    background: #ededed;
    font-weight: normal;
    color: #2b2b2b;
}
.ui-state-hover a,
.ui-state-hover a:hover,
.ui-state-hover a:link,
.ui-state-hover a:visited,
.ui-state-focus a,
.ui-state-focus a:hover,
.ui-state-focus a:link,
.ui-state-focus a:visited,
a.ui-button:hover,
a.ui-button:focus {
    color: #2b2b2b;
    text-decoration: none;
}

.ui-visual-focus {
    box-shadow: 0 0 3px 1px rgb(94, 158, 214);
}
.ui-state-active,
.ui-widget-content .ui-state-active,
.ui-widget-header .ui-state-active,
a.ui-button:active,
.ui-button:active,
.ui-button.ui-state-active:hover {
    border: 1px solid #003eff;
    background: #007fff;
    font-weight: normal;
    color: #fff;
}
.ui-icon-background,
.ui-state-active .ui-icon-background {
    border: #003eff;
    background-color: #fff;
}
.ui-state-active a,
.ui-state-active a:link,
.ui-state-active a:visited {
    color: #fff;
    text-decoration: none;
}

/* Misc visuals
----------------------------------*/

/* Corner radius */
.ui-corner-all,
.ui-corner-top,
.ui-corner-left,
.ui-corner-tl {
    border-top-left-radius: 3px;
}
.ui-corner-all,
.ui-corner-top,
.ui-corner-right,
.ui-corner-tr {
    border-top-right-radius: 3px;
}
.ui-corner-all,
.ui-corner-bottom,
.ui-corner-left,
.ui-corner-bl {
    border-bottom-left-radius: 3px;
}
.ui-corner-all,
.ui-corner-bottom,
.ui-corner-right,
.ui-corner-br {
    border-bottom-right-radius: 3px;
}

/* Overlays */
.ui-widget-overlay {
    background: #aaa;
    opacity: .3;
}
.ui-widget-shadow {
    -webkit-box-shadow: 0 0 5px #666;
    box-shadow: 0 0 5px #666;
}

/* Styles for varmatrix_input */
.varmatrixinputdiv {
    border-left: 1px solid black;
    border-right: 1px solid black;
    position: relative;
    display: inline-block;
    padding: 5px;
    min-width: 20px;
    min-height: 20px;
}
.varmatrixinputspan {
    outline: none;
    background: white;
    padding: 3px;
}
.varmatrixBorderTopLeft {
    background: black;
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    width: 10px;
    height: 1px;
}
.varmatrixBorderTopRight {
    background: black;
    content: "";
    position: absolute;
    top: 0;
    right: 0;
    width: 10px;
    height: 1px;
}
.varmatrixBorderBottomLeft {
    background: black;
    content: "";
    position: absolute;
    bottom: 0;
    left: 0;
    width: 10px;
    height: 1px;
}
.varmatrixBorderBottomRight {
    background: black;
    content: "";
    position: absolute;
    bottom: 0;
    right: 0;
    width: 10px;
    height: 1px;
}

/*****************************************
                   HELM
*****************************************/
.HELM_exercise {
    font-weight: bold;
    font-size: 110%;
}
.HELM_exercise:before {
    font-family: "FontAwesome", "Font Awesome 6 Free";
    content: "\f040";
    padding-right: 0.5rem;
    font-size: 120%;
    display: inline-block;
}
h4.HELM_example,
.HELM_example {
    font-size: 95%;
    background: #1e92cc;
    color: #fff;
    text-shadow: none;
    padding: 0.5em;
    display: inline-block;
    margin: -0.5em -0.5em 0.5em 0;
    border-radius: 0.2em;
}
h4.HELM_example:before,
.HELM_example:before {
    font-family: "FontAwesome", "Font Awesome 6 Free";
    content: "\f046";
    display: inline-block;
    padding-right: 0.5em;
    vertical-align: middle;
    font-weight: 500;
    font-size: 120%;
}
.HELM_solution {
    font-size: 95%;
    color: #1e92cc;
}
.HELM_part {
    background: #1e92cc;
    color: #fff;
    text-shadow: none;
    border-radius: 0.2em;
    padding: 0.3rem;
    margin-left: 1em;
}
ol.HELM_parts {
    list-style: none;
    counter-reset: helm-parts;
    margin-top: 1rem;
    width: 100%;
}
ol.HELM_parts > li {
    counter-increment: helm-parts;
    margin-bottom: 1.5rem;
    display: block;
}
ol.HELM_parts > li > :first-child {
    display: inline-block;
}

ol.HELM_parts > li:before {
    content: "(" counter(helm-parts, lower-alpha) ")";
    margin-left: -2.2rem;
    margin-top: -0.2rem;
    margin-right: 0.4rem;
    background: #1e92cc;
    border-radius: 0.2rem;
    color: white;
    text-shadow: none;
    padding: 0.3rem;
    text-align: center;
    display: inline-block;
    box-sizing: border-box;
    vertical-align: top;
}

ol.HELM_parts_inline {
    list-style: none;
    padding: 0;
    counter-reset: helm-parts;
    float: left;
    width: 100%;
    margin-left: 2.5rem;
}
ol.HELM_parts_inline > li {
    counter-increment: helm-parts;
    display: inline;
    margin-left: -2.2rem;
}
ol.HELM_parts_inline > li::before {
    content: "(" counter(helm-parts, lower-alpha) ")";
    margin-right: 1ex;
    margin-top: -0.3rem;
    background: #1e92cc;
    border-radius: 0.2rem;
    color: white;
    text-shadow: none;
    padding: 0.3rem;
    text-align: center;
    display: inline-block;
    box-sizing: border-box;
}
ol.HELM_parts_inline > li:not(:last-child)::after {
    content: "";
    margin-right: 4rem;
}
/* Make ordered lists within ordered lists display in lower-roman (i) style. */
ol.HELM_parts > li > ol.HELM_parts > li:before {
    content: "(" counter(helm-parts, lower-roman) ")";
}

div.HELM_keypoint {
    border: 1px solid #1e92cc;
    border-left-width: 3px;
    padding: 0.2rem 1rem;
}
.HELM_keypoint h4 {
    font-size: 110%;
    color: #1e92cc;
}
.HELM_keypoint h4:before {
    font-family: "FontAwesome", "Font Awesome 6 Free";
    content: "\f0a9";
    padding-right: 0.5rem;
    font-size: 120%;
    display: inline-block;
}

/* Define HELM table styling. */
table.HELM_table {
    text-align: center;
    margin-left: auto;
    margin-right: auto;
}
table.HELM_table th {
    border-bottom: 1px solid black;
}
table.HELM_table td,
table.HELM_table th {
    padding: 5px;
    padding-left: 10px;
    padding-right: 10px;
    border-right: 1px solid black;
}
table.HELM_table td:last-child,
table.HELM_table th:last-child {
    border-right: 0;
}

/* RTL support */

/* Student answer form fields */
.que.stack .algebraic,
.que.stack .algebraic-units,
.que.stack .numerical,
.que.stack .maxima-string,
.que.stack .maxima-list,
.que.stack .equiv,
.que.stack .equivinput,
.que.stack .varmatrixinput,
.que.stack .matrixtable,
.que.stack .freetextinput,
/* Question authoring form */
#page-question-type-stack textarea#id_questionvariables,
#page-question-type-stack input#id_variantsselectionseed,
#page-question-type-stack #id_questionnote,
#page-question-type-stack #id_prt1feedbackvariables,
#page-question-type-stack input#id_ans1modelans,
#page-question-type-stack input#id_ans1allowwords,
#page-question-type-stack input#id_ans1options {
    display: inline-block;
    /*rtl:ignore*/
    direction: ltr;
}
/* Properly display inversetrig values, in RTL mode */
#page-question-type-stack #id_inversetrig option {
    unicode-bidi: plaintext;
}

/* Support for side by side style in free-text editors. */
.free-text-container {
    display: flex;
    gap: 1rem;
    align-items: stretch;  /* Make children same height. */
    width: max-content;
    max-width: 100%;
}

.free-text-container-vertical {
    width: max-content;
    max-width: 100%;
}

.free-text-container > * {
    flex: 1;
    min-width: 0;
}

.free-text-container iframe {
    flex: 1 1 auto;
    height: 100%;
}

.free-text-container [id^=stack-iframe-holder] {
    height: auto;
    display: flex;
}

#source {
    resize: vertical;
    box-sizing: border-box;
}

/* Stack vertically on narrow screens */
@media (max-width: 768px) {
    .free-text-container {
        flex-direction: column;
        width: 100%;
    }

    .free-text-container > * {
        flex: none;
        width: 100%;
    }

    .free-text-container > textarea {
        box-sizing: border-box;
        width: 100%;
    }
}

/* Trees: https://codepen.io/ross-angus/pen/jwxMjL
Copyright (c) 2022 by Ross Angus (https://codepen.io/ross-angus/pen/jwxMjL)

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.
*/

/* It's supposed to look like a tree diagram. */
.algebratree,
.algebratree ul,
.algebratree li {
    list-style: none;
    margin: 0;
    padding: 0;
    position: relative;
}

.algebratree {
    margin: 0 0 1em;
    text-align: center;
}
.algebratree,
.algebratree ul {
    display: table;
}
.algebratree ul {
    width: 100%;
}
.algebratree li {
    display: table-cell;
    padding: .5em 0;
    vertical-align: top;
}
/* _________ */
.algebratree li:before {
    outline: solid 1px #666;
    content: "";
    left: 0;
    position: absolute;
    right: 0;
    top: 0;
}
.algebratree li:first-child:before {
    left: 50%;
}
.algebratree li:last-child:before {
    right: 50%;
}
.algebratree span.atom,
.algebratree span.op,
.algebratree span.cell,
.algebratree code {
    border: solid .1em #666;
    border-radius: .2em;
    display: inline-block;
    margin: 0 .2em .5em;
    padding: .2em .5em;
    position: relative;
}
/* If the tree represents DOM structure. */
.algebratree span.atom {
    border-radius: .5em;
    color: DarkRed;
    background-color: LightCyan;
}
.algebratree code,
.algebratree span.op {
    border-radius: .2em;
    color: Red;
    background-color: LemonChiffon;
}
/* | */
.algebratree ul:before,
.algebratree span.atom:before,
.algebratree span.op:before,
.algebratree span.cell:before,
.algebratree code:before {
    outline: solid 1px #666;
    content: "";
    height: .5em;
    left: 50%;
    position: absolute;
}
.algebratree ul:before {
    top: -.5em;
}
.algebratree span.atom:before,
.algebratree span.op:before,
.algebratree span.cell:before,
.algebratree code:before {
    top: -.55em;
}
/* The root node doesn't connect upwards. */
.algebratree > li {
    margin-top: 0;
}
.algebratree > li:before,
.algebratree > li:after,
.algebratree > li > span.atom:before,
.algebratree > li > span.op:before,
.algebratree > li > span.cell:before,
.algebratree > li > code:before {
    outline: none;
}

/* Response Analysis */
.stack-collapse-header {
    cursor: pointer;
}
.stack-collapse-header:not(.collapsed):before {
    font-family: "FontAwesome", "Font Awesome 6 Free";
    content: "\f0d7";
    font-weight: bold;
    display: inline-block;
}
.stack-collapse-header.collapsed:before {
    font-family: "FontAwesome", "Font Awesome 6 Free";
    content: "\f0da";
    font-weight: bold;
    display: inline-block;
}
.stack-ra-report::marker {
    font-size: 1.4rem;
}
.stack-ra-question {
    max-width: 800px;
    background-color: rgb(230, 247, 255);
    border-radius: 10px;
    padding: 1em;
    white-space: pre-line;
}
.stack-ra-question * {
    margin: 0;
}
.stack-library-file-list {
    padding: 20px 0 20px 0;
    height: 400px;
    overflow-y: scroll;
    border: 1px solid lightblue;
    border-radius: 10px;
}
.stack-library-import-success {
    padding: 5px 0 5px 10px;
    background-color: lightgreen;
    border-radius: 10px;
}
.stack-library-import-failure {
    padding: 5px 0 5px 10px;
    background-color: pink;
    border-radius: 10px;
}
.que .outcome,
.que .comment {
    color: #44331b;
}
.stack-dash-tab-load:hover {
    cursor: not-allowed;
}
.stacktestsuite .results-symbol {
    font-size: 1.5em;
}