stylus/global.css

html#stylus #header *:not(#\1transition-suppressor) {
  /* This suppresses a bug in all? browsers: they apply transitions during page load.
   * Using an increased specificity to override sane selectors in user styles.
   * Using \1 to simplify js code because \0 is converted to \xFFFD per spec. */
  transition: none !important;
}
:root {
  --family: Arial, "Helvetica Neue", Helvetica, system-ui, sans-serif;
  --input-height: 22px;
  --cmin: hsl(0, 0%, 00%);
  --c00: hsl(0, 0%, 00%);
  --c10: hsl(0, 0%, 10%);
  --c20: hsl(0, 0%, 20%);
  --c30: hsl(0, 0%, 30%);
  --c40: hsl(0, 0%, 40%);
  --c45: hsl(0, 0%, 45%);
  --c50: hsl(0, 0%, 50%);
  --c60: hsl(0, 0%, 60%);
  --c65: hsl(0, 0%, 65%);
  --c70: hsl(0, 0%, 70%);
  --c75: hsl(0, 0%, 75%);
  --c80: hsl(0, 0%, 80%);
  --c85: hsl(0, 0%, 85%);
  --c90: hsl(0, 0%, 90%);
  --c95: hsl(0, 0%, 95%);
  --c100: hsl(0, 0%, 100%);
  --cmax: hsl(0, 0%, 100%);
  --bg: var(--c100);
  --fg: var(--c00);
  --accent-1: hsl(180, 100%, 15%);
  --accent-2: hsl(180, 50%, 40%);
  --accent-3: hsl(180, 40%, 69%);
}
body {
  font: normal 12px var(--family);
  background-color: var(--bg);
  color: var(--fg);
  margin: 0;
}
body:lang(ja) {
  font-family: Arial, 'Meiryo UI', 'MS Gothic', system-ui, sans-serif;
}
body:lang(zh-CN) {
  font-family: Arial, 'Microsoft YaHei UI', 'Microsoft YaHei', system-ui, sans-serif;
}
body:lang(zh-TW),
body:lang(zh-HK) {
  font-family: Arial, 'Microsoft JhengHei UI', 'Microsoft JhengHei', system-ui, sans-serif;
}

button {
  -webkit-appearance: none;
  -moz-appearance: none;
  user-select: none;
  max-width: 100%;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  padding: 2px 7px;
  border: 1px solid var(--c60);
  font: inherit;
  font-size: 13px;
  line-height: 1.2;
  color: var(--fg);
  background-color: var(--bg);
  background-image: url('data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAAeCAYAAADtlXTHAAAABmJLR0QA/wD/AP+gvaeTAAAACXBIWXMAAAsTAAALEwEAmpwYAAAAB3RJTUUH4QwGBBwIHvKt6QAAAB1pVFh0Q29tbWVudAAAAAAAQ3JlYXRlZCB3aXRoIEdJTVBkLmUHAAAAL0lEQVQI12NoaGgQZ2JgYGBkYmBgYGZiYGBggrMY4VxsYsyoskQQCB2MWAxAMhkADVECDhlW9CoAAAAASUVORK5CYII=');
  background-repeat: repeat-x;
  background-size: 100% 100%;
  transition: background-color .25s, border-color .25s;
}

button:not(:disabled):hover {
  background-color: var(--c95);
  border-color: var(--c50);
}

button:active {
  background-color: var(--c95);
  border-color: var(--c50);
  background-image: url('data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAAeCAYAAADtlXTHAAAABmJLR0QA/wD/AP+gvaeTAAAACXBIWXMAAAsTAAALEwEAmpwYAAAAB3RJTUUH4QwJARIWJNZvuQAAAB1pVFh0Q29tbWVudAAAAAAAQ3JlYXRlZCB3aXRoIEdJTVBkLmUHAAAAMElEQVQI12NoaGgIZmJgYPjLxMDA8I+JgYHhP5z1Dy7xH5X7jxQCzWQ0A9DEILYBABm5HtJk2jPHAAAAAElFTkSuQmCC');
  background-repeat: repeat-x;
  background-size: 100% 100%;
}

button .svg-icon {
  cursor: auto;
}

/* For some odd reason these hovers appear lighter than all other button hovers in every browser */
#message-box-buttons button:not(:disabled):hover {
  background-color: var(--c90);
  border-color: var(--c50);
}

input {
  font: inherit;
  border: 1px solid var(--c65);
  transition: border-color .1s, box-shadow .1s;
}

input:not([type]),
input[type=text],
input[type=number],
input[type=search] {
  background: var(--bg);
  color: var(--fg);
  height: var(--input-height);
  min-height: var(--input-height)!important;
  line-height: var(--input-height);
  box-sizing: border-box;
  padding: 0 3px;
  border: 1px solid var(--c65);
}

.svg-icon {
  cursor: pointer;
  vertical-align: middle;
  transition: fill .5s;
  width: 20px;
  height: 20px;
  fill: var(--c40);
}

.svg-icon:hover {
  fill: var(--fg);
}

.svg-icon.info {
  width: 14px;
  height: 16px;
  margin-left: .5ex;
}

.svg-icon.config {
  width: 16px;
  height: 16px;
}

.svg-icon.checked {
  position: absolute;
  height: 8px;
  width: 8px;
  display: none;
  fill: var(--fg);
  margin: 2px 0 0 2px;
}

input[type="checkbox"]:not(.slider):checked + .svg-icon.checked {
  display: inline-flex;
  transition: fill .1s;
}

input[type="checkbox"]:not(.slider) {
  -webkit-appearance: none;
  -moz-appearance: none;
  position: absolute;
  left: 0;
  top: 0;
  border: 1px solid var(--c45);
  height: 12px;
  width: 12px;
  display: inline-flex;
  border-radius: 2px;
  background-color: hsla(0, 0%, 0%, .1);
  margin: 0;
  transition: background-color .1s, border-color .1s;
}

input[type="checkbox"]:not(.slider):hover {
  border-color: var(--c30);
  background-color: var(--c80);
}

input[type="checkbox"]:not(.slider):checked + .svg-icon.checked {
  position: absolute;
  top: 0;
  left: 0;
  pointer-events: none;
}

input[type="checkbox"]:not(.slider):disabled {
  background-color: transparent;
  border-color: var(--c50);
}

input[type="checkbox"]:not(.slider):disabled + .svg-icon.checked {
  fill: var(--c50);
}

input[type="checkbox"]:not(.slider):disabled + .svg-icon.checked + span {
  color: var(--c50);
}

label {
  transition: color .1s;
}

select {
  -moz-appearance: none;
  -webkit-appearance: none;
  height: var(--input-height);
  font: inherit;
  color: var(--fg);
  background-color: transparent;
  border: 1px solid var(--c65);
  padding: 0 20px 0 6px;
  transition: color .5s;
}

.select-wrapper,
.select-resizer {
  display: inline-flex!important;
  cursor: default;
  position: relative;
}

.svg-icon.select-arrow {
  pointer-events: none;
  cursor: default;
  display: inline-flex;
  height: 14px;
  width: 14px;
  fill: var(--fg);
  position: absolute;
  top: 4px;
  right: 4px;
  transition: fill .5s;
}

input[type="radio"] {
  -webkit-appearance: none;
  -moz-appearance: none;
  background: var(--c90);
  border-radius: 50%;
  border: 1px solid var(--c60);
  cursor: default;
  height: 13px;
  width: 13px;
  position: relative;
  margin: 0 4px 1px 0;
}
input[type="radio"]:after {
  content: '';
  background-color: transparent;
  transform: scale(0);
  transform-origin: 50% 50%;
  transition: background-color .5s, transform .5s;
  border-radius: 50%;
  height: 7px;
  width: 7px;
  left: 2px;
  top: 2px;
  position: absolute;
}
input[type="radio"]:checked:after {
  background-color: var(--c30);
  transform: scale(1);
}
.radio-wrapper {
  display: flex;
  align-items: center;
  line-height: 1.5;
}

/* restore disabled state dimming */
button:disabled,
select:disabled,
option:disabled,
select[disabled] > option {
  color: graytext;
}

select:disabled + .select-arrow,
select[disabled] + .select-arrow {
  fill: var(--c50);
}

summary {
  -moz-user-select: none;
  user-select: none;
}

/* global stuff we use everywhere */
.hidden {
  display: none !important;
}

:focus,
.CodeMirror-focused,
/* Allowing click outline on text/search inputs and textareas */
textarea[data-focused-via-click]:focus,
input:not([type])[data-focused-via-click]:focus, /* same as "text" */
input[type="text"][data-focused-via-click]:focus,
input[type="url"][data-focused-via-click]:focus,
input[type="search"][data-focused-via-click]:focus,
input[type="number"][data-focused-via-click]:focus {
  /* Using box-shadow instead of the ugly outline in new Chrome */
  outline: none;
  box-shadow: 0 0 0 1px hsl(180, 100%, 38%), 0 0 3px hsla(180, 100%, 60%, .5);
}

[data-focused-via-click] :focus,
[data-focused-via-click]:focus {
  outline: none;
  box-shadow: none;
}

/* header resizer */
:root {
  --header-width: 280px;
  --header-resizer-width: 8px;
}
#header-resizer {
  position: absolute;
  top: 0;
  right: 0;
  bottom: 0;
  width: var(--header-resizer-width);
  box-sizing: border-box;
  cursor: e-resize;
  border-width: 0 1px;
  border-style: solid;
  color: hsla(0, 0%, 50%, .5);
  border-color: currentColor;
  pointer-events: auto;
}
#header-resizer:active {
  border-color: var(--c50);
}
#header-resizer::after {
  content: '';
  position: absolute;
  border-right: 2px dotted currentColor;
  left: 2px;
  width: 0;
  height: 100%;
}
body.resizing-h {
  cursor: e-resize;
}
body.resizing-v {
  cursor: n-resize;
}
body.resizing-h > *,
body.resizing-v > * {
  pointer-events: none;
  -moz-user-select: none;
  user-select: none;
}
/* header resizer - end */

.split-btn {
  position: relative;
  white-space: nowrap;
}
.split-btn-pedal {
  margin-left: -1px !important;
  padding-left: .25em !important;
  padding-right: .25em !important;
  min-width: 0 !important;
}
.split-btn-pedal::after {
  --side: 4px;
  content: '';
  border: var(--side) solid transparent;
  display: inline-block;
  border-top: calc(var(--side) * 1.3) solid currentColor;
  vertical-align: bottom;
}
.split-btn-pedal.active {
  box-shadow: inset 0 0 100px rgba(0, 0, 0, .2);
}
.split-btn-menu {
  background: var(--bg);
  position: absolute;
  box-shadow: 2px 3px 7px rgba(0, 0, 0, .5);
  border: 1px solid hsl(180deg, 50%, 50%);
  white-space: nowrap;
  cursor: pointer;
  padding: .25em 0;
  z-index: 1000;
}
.split-btn-menu > * {
  padding: .5em 1em;
  display: block;
}
.split-btn-menu > :hover {
  background-color: hsla(180deg, 50%, 50%, .25);
  color: var(--fg);
}

@supports (-moz-appearance: none) {
  .firefox select {
    padding: 0 20px 0 2px;
    line-height: var(--input-height)!important;
  }

  svg {
    transform: scale(1); /* de-blur */
  }

/* We can customize everything about number inputs except arrows. They're horrible in Linux FF, so we'll hide them unless hovered or focused. */
  .firefox.non-windows input[type="number"] {
    -moz-appearance: textfield;
    background: var(--bg);
    color: var(--fg);
    border: 1px solid var(--c65);
  }

  .firefox.non-windows input[type="number"]:not(:disabled):hover,
  .firefox.non-windows input[type="number"]:focus {
    -moz-appearance: number-input;
  }

  .firefox.non-windows input[type="color"] {
    background: var(--bg);
    border: 1px solid var(--c65);
    padding: 4px;
  }
}

@media (max-width: 850px) {
  #header-resizer {
    display: none !important;
  }
}