misode.github.io/src/styles/nodes.css

:root {
  --node-border: #bcbfc3;
  --node-background-label: #e4e4e4;
  --node-background-input: #ffffff;
  --node-text: #000000;
  --node-selected: #f0e65e;
  --node-selected-border: #b9a327;
  --node-add: #9bd464;
  --node-add-border: #498d09;
  --node-remove: #e76f51;
  --node-remove-border: #be4b2e;
  --node-indent-border: #b9b9b9;
  --node-popup: #1f2020e6;
  --category-predicate: #65b5b8;
  --category-predicate-border: #187e81;
  --category-function: #979fa7;
  --category-function-border: #788086;
}

:root[data-theme=dark] {
  --node-border: #4e4e4e;
  --node-background-label: #1b1b1b;
  --node-background-input: #272727;
  --node-text: #dadada;
  --node-selected: #ad9715;
  --node-selected-border: #8d7a0d;
  --node-add: #5a961e;
  --node-add-border: #3b6e0c;
  --node-remove: #b64023;
  --node-remove-border: #7e1d05;
  --node-indent-border: #454749;
  --node-popup: #0a0a0ae6;
  --category-predicate: #306163;
  --category-predicate-border: #224849;
  --category-function: #838383;
  --category-function-border: #6b6b6b;
}

.tree > div > .object-node > .node-body {
  border-left: none;
  padding-left: 0;
}

.tree > div > .node > .node-body {
  margin-top: -5px; /* no idea why this is necessary */
}

.node {
  margin: 2px 0;
}

.node-body > .node:first-child {
  margin-top: 4px;
}

.node:last-child {
  margin-bottom: 0;
}

.node-body {
  border-left: 3px solid var(--node-indent-border);
  transition: border-color var(--style-transition);
}

/* Node headers */

.node-header {
  display: inline-flex;
  align-items: center;
  max-width: 100%;
}

.node-header > * {
  height: 34px;
  border: 1px solid;
  color: var(--node-text);
  border-color: var(--node-border);
  transition: all var(--style-transition);
}

.node-header > label {
  padding: 0 9px;
  line-height: 1.94rem;
  user-select: none;
  white-space: nowrap;
  background-color: var(--node-background-label);
}

.node-header > input {
  font-size: 18px;
  padding-left: 9px;
  background-color: var(--node-background-input);
}

.node-header > select {
  font-size: 18px;
  padding-left: 6px;
  background-color: var(--node-background-input);
}

.node-header > button {
  font-size: 18px;
  padding: 0 9px;
  line-height: 1.94rem;
  user-select: none;
  cursor: pointer;
  background-color: var(--node-background-input);
}

.object-node > .node-header > .collapse {
  cursor: pointer;
}

/** Rounded corners */

.node-header > *:first-child {
  border-top-left-radius: 3px;
  border-bottom-left-radius: 3px;
}

.node-header > *:last-child,
.node-header > input[list]:nth-last-child(2),
.node-header[data-help] > *:nth-last-child(2),
.node-header[data-help] > input[list]:nth-last-child(3),
.node-header[data-error] > *:nth-last-child(2),
.node-header[data-error] > input[list]:nth-last-child(3),
.node-header[data-help][data-error] > *:nth-last-child(3),
.node-header[data-help][data-error] > input[list]:nth-last-child(4) {
  border-top-right-radius: 3px;
  border-bottom-right-radius: 3px;
}

.node-header > *:not(:last-child) {
  margin-right: -1px;
}

.object-node > .node-header > *:first-child,
.map-node > .node-header > *:first-child,
.list-node > .node-header > *:first-child {
  border-top-left-radius: 8px;
  border-bottom-left-radius: 0;
}

.node-header > .collapse.closed {
  border-bottom-left-radius: 3px;
}

/* Buttons */

button.selected {
  background-color: var(--node-selected);
  border-color: var(--node-selected-border);
}

.collapse {
  display: inline-flex;
  align-items: center;
}

.collapse svg {
  fill: var(--node-text);
  transition: fill var(--style-transition);
}

.collapse.closed,
button.add {
  background-color: var(--node-add);
  border-color: var(--node-add-border);
}

.collapse.open,
button.remove {
  background-color: var(--node-remove);
  border-color: var(--node-remove-border);
}

button.remove svg,
button.add svg {
  display: inline-block;
  position: relative;
  top: 2px;
  fill: var(--node-text);
  transition: fill var(--style-transition);
}

.node-header > button.add:last-child {
  border-top-right-radius: 6px;
  border-bottom-right-radius: 6px;
}

.node-icon {
  border: none;
  position: relative;
  display: inline-block;
}

.node-icon svg {
  cursor: pointer;
}

.node-icon .icon-popup {
  visibility: hidden;
  width: 240px;
  background-color: var(--node-popup);
  color: var(--node-text);
  text-align: center;
  border-radius: 6px;
  padding: 8px 4px;
  position: absolute;
  z-index: 1;
  top: 125%;
  left: 50%;
  margin-left: -120px;
}

.node-icon .icon-popup::after {
  content: "";
  position: absolute;
  bottom: 100%;
  left: 50%;
  margin-left: -3px;
  border-width: 5px;
  border-style: solid;
  border-color: transparent transparent var(--node-popup) transparent;
}

.node-icon:hover .icon-popup,
.node-icon .icon-popup.show {
  visibility: visible;
}

.node-icon > svg {
  height: 34px;
  width: 34px;
  min-width: 34px;
  margin-left: 6px;
}

.node-header svg.node-help {
  fill: var(--node-border);
}

.node-header svg.node-error {
  fill: var(--node-remove);
}

/* Node body and list entry */

.node-body {
  display: flex;
  flex-direction: column;
  padding-left: 14px;
}

.node-entry > .object-node > .node-body {
  padding-left: 0;
}

.node-entry > .object-node > .node-body > .node > .node-body {
  border-left: none;
}

.node-entry > .object-node > .node-body > .node.node-header > *:first-child,
.node-entry > .object-node > .node-body > .node > .node-header > *:first-child {
  border-top-left-radius: 0;
  border-bottom-left-radius: 0;
  border-left: none;
}

.node-entry {
  display: flex;
  flex-direction: column;
  margin-top: 2px;
}

/* Node type specifics */

.range-node select {
  width: 25px;
}

.number-node input,
.range-node input {
  width: 100px;
}

/* Color categories */

[data-category=predicate] > .node-header > label,
[data-category=predicate] > .node-body > .node.node-header > *:first-child,
[data-category=predicate] > .node-body > .node > .node-header > *:first-child {
  background-color: var(--category-predicate) !important;
}

[data-category=predicate] > .node-body,
[data-category=predicate] > .node-header > label,
[data-category=predicate] > .node-body > .node.node-header > *:not(button),
[data-category=predicate] > .node-body > .node > .node-header > *:not(button) {
  border-color: var(--category-predicate-border) !important;
}

[data-category=function] > .node-header > label,
[data-category=function] > .node-body > .node.node-header > *:first-child,
[data-category=function] > .node-body > .node > .node-header > *:first-child {
  background-color: var(--category-function) !important;
}

[data-category=function] > .node-body,
[data-category=function] > .node-header > label,
[data-category=function] > .node-body > .node.node-header > *:not(button),
[data-category=function] > .node-body > .node > .node-header > *:not(button) {
  border-color: var(--category-function-border) !important;
}