#canvas { 
    border: 1px solid black; 
    display: block; 
    margin: auto; 
    box-sizing: border-box;
}

#zoom-button {
  /* width: 64px;
  height: 64px; */
  background-color: white;
  position: absolute;
  bottom: 3px; 
  right: 3px;
}

.group-padding {
  margin: 10px 0;
}

.slider-group {
    /* border: 1px solid blue;
    padding: 8px;
    border-radius: 4px; */
    margin-bottom: 6px;
}

.controls h4 {
    padding: 0;
    margin: 0 0 10px 0;
}

.flex {
  display: flex; 
  align-items: center;
  /* border: 1px solid blue; */
}

.flex-auto {
    flex: 1 1 auto;
    /* border: 1px dashed red; */
    width: 100%;
    box-sizing: border-box;
}

.text-center {
    text-align: center;
}

.group-label {
  font-size: 14px;
  font-weight: 600;
  line-height: 21px
}



:root {
  --color-btn-primary-hover-bg: #2c974b;
  --color-btn-text: #24292f;
  --color-btn-active-bg: hsla(220, 14%, 93%, 1);
  --color-btn-selected-bg: hsla(220, 14%, 94%, 1);
  --color-primer-shadow-inset: inset 0 1px 0 rgba(208, 215, 222, 0.2);
  --color-fg-muted: #57606a;
  --color-btn-bg: #f6f8fa;
  --color-btn-border: rgba(27, 31, 36, 0.15);
  --color-btn-shadow: 0 1px 0 rgba(27, 31, 36, 0.04);
  --color-btn-inset-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.25);
  --border-width: 1px;
  --border-style: solid;
  --font-size-small: 12px;
  --font-weight-semibold: 500;
  --size-2: 20px;
  --color-border-default: #d0d7de;
}


.btn {
    position: relative;
    display: inline-block;
    padding: 5px 16px;
    font-size: 14px;
    font-weight: 500;
    line-height: 20px;
    white-space: nowrap;
    vertical-align: middle;
    cursor: pointer;
    -webkit-user-select: none;
    user-select: none;
    border: 1px solid;
    border-radius: 6px;
    -webkit-appearance: none;
    -moz-appearance: none;
    appearance: none
}

.btn:hover {
    text-decoration: none
}

.btn:disabled, .btn.disabled {
    cursor: default
}

.btn:disabled .btn.disabled {
    color: var(--color-fg-muted)
}
.btn .dropdown-caret {
    margin-left: 4px;
    opacity: 0.8
}



.btn {
    color: var(--color-btn-text);
    background-color: var(--color-btn-bg);
    border-color: var(--color-btn-border);
    box-shadow: var(--color-btn-shadow), var(--color-btn-inset-shadow);
    transition: 0.2s cubic-bezier(0.3, 0, 0.5, 1);
    transition-property: color, background-color, border-color
}

.btn:hover, .btn.hover, [open] > .btn {
    background-color: var(--color-btn-hover-bg);
    border-color: var(--color-btn-hover-border);
    transition-duration: 0.1s
}

.btn:active {
    background-color: var(--color-btn-active-bg);
    border-color: var(--color-btn-active-border);
    transition: none
}

.btn.selected, .btn[aria-selected=true] {
    background-color: var(--color-btn-selected-bg);
    box-shadow: var(--color-primer-shadow-inset)
}

.btn:disabled, .btn.disabled, .btn[aria-disabled=true] {
    color: var(--color-fg-muted);
    background-color: var(--color-btn-bg);
    border-color: var(--color-btn-border)
}

.btn:focus, .btn.focus {
    border-color: var(--color-btn-focus-border);
    outline: none;
    box-shadow: var(--color-btn-focus-shadow)
}

.btn-primary {
    color: var(--color-btn-primary-text);
    background-color: var(--color-btn-primary-bg);
    border-color: var(--color-btn-primary-border);
    box-shadow: var(--color-btn-primary-shadow), var(--color-btn-primary-inset-shadow)
}

.btn-primary:hover, .btn-primary.hover, [open] > .btn-primary {
    background-color: var(--color-btn-primary-hover-bg);
    border-color: var(--color-btn-primary-hover-border)
}

.btn-primary:active, .btn-primary.selected, .btn-primary[aria-selected=true] {
    background-color: var(--color-btn-primary-selected-bg);
    box-shadow: var(--color-btn-primary-selected-shadow)
}

.btn-primary:disabled, .btn-primary.disabled, .btn-primary[aria-disabled=true] {
    color: var(--color-btn-primary-disabled-text);
    background-color: var(--color-btn-primary-disabled-bg);
    border-color: var(--color-btn-primary-disabled-border)
}

.btn-primary:disabled .octicon, .btn-primary.disabled .octicon, .btn-primary[aria-disabled=true] .octicon {
    color: var(--color-btn-primary-disabled-text)
}

.btn-outline {
    color: var(--color-btn-outline-text)
}

.btn-outline:hover, [open] > .btn-outline {
    color: var(--color-btn-outline-hover-text);
    background-color: var(--color-btn-outline-hover-bg);
    border-color: var(--color-btn-outline-hover-border);
    box-shadow: var(--color-btn-outline-hover-shadow), var(--color-btn-outline-hover-inset-shadow)
}

.btn-outline:hover .Counter, [open] > .btn-outline .Counter {
    background-color: var(--color-btn-outline-hover-counter-bg)
}

.btn-outline:hover .octicon, [open] > .btn-outline .octicon {
    color: inherit
}

.btn-outline:active, .btn-outline.selected, .btn-outline[aria-selected=true] {
    color: var(--color-btn-outline-selected-text);
    background-color: var(--color-btn-outline-selected-bg);
    border-color: var(--color-btn-outline-selected-border);
    box-shadow: var(--color-btn-outline-selected-shadow)
}

.btn-outline:disabled, .btn-outline.disabled, .btn-outline[aria-disabled=true] {
    color: var(--color-btn-outline-disabled-text);
    background-color: var(--color-btn-outline-disabled-bg);
    border-color: var(--color-btn-border);
    box-shadow: none
}

.btn-outline:disabled .Counter, .btn-outline.disabled .Counter, .btn-outline[aria-disabled=true] .Counter {
    background-color: var(--color-btn-outline-disabled-counter-bg)
}

.btn-outline:focus {
    border-color: var(--color-btn-outline-focus-border);
    box-shadow: var(--color-btn-outline-focus-shadow)
}

.btn-sm {
    padding: 3px 12px;
    font-size: 12px;
    line-height: 20px
}

.btn-large {
    padding: .75em 1.5em;
    font-size: inherit;
    line-height: 1.5;
    border-radius: 0.5em
}

.btn-block {
    display: block;
    width: 100%;
    text-align: center
}

.btn-group {
    display: flex;
}

.btn-group button:first-of-type {
  border-top-left-radius: 6px;
  border-bottom-left-radius: 6px;
}

.btn-group button:last-of-type {
  border-top-right-radius: 6px;
  border-bottom-right-radius: 6px;
}

.btn-group button {
  border-radius: 0;
  flex: 1 1 50%;
}

.form-control {
  padding: 5px 12px;
  font-size: 14px;
  line-height: 20px;
  color: var(--color-fg-default);
  vertical-align: middle;
  background-color: var(--color-canvas-default);
  background-repeat: no-repeat;
  background-position: right 8px center;
  border: 1px solid var(--color-border-default);
  border-radius: 6px;
  outline: none;
  box-shadow: var(--color-primer-shadow-inset);
}