index.css

* {
  margin: 0;
  padding: 0;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen',
    'Ubuntu', 'Cantarell', 'Fira Sans', 'Droid Sans', 'Helvetica Neue',
    sans-serif;
}

h1,
h2,
h3,
h4 {
  margin-top: 24px;
}

code {
  font-family: source-code-pro, Menlo, Monaco, Consolas, 'Courier New',
    monospace;
}

kbd {
  margin-left: 4px;
  padding: 2px 4px;
  font-size: 90%;
  color: #fff;
  background-color: #333;
  border-radius: 3px;
  box-shadow: inset 0 -1px 0 rgba(0, 0, 0, 0.25);
}

table {
  border-collapse: collapse;
}
table:not(.busy) tr {
  border-bottom: 1px solid #666;
}

table.busy thead tr {
  border-bottom: 1px solid #000;
}
table.busy tbody tr:nth-child(even) {
  background: #ccc;
}

.grey {
  color: #999;
}
.red {
  color: #f44336;
}

a {
  text-decoration: none;
  color: #1e90ff;
}
a:not(.start):hover {
  color: #1e40ff;
  cursor: pointer;
}
a:not(.start):visited {
  color: #1e20ff;
}

.start {
  display: block;
}
.start {
  background-color: #1e90ff;
  color: #fff;
  padding: 1em 1.5em;
  text-decoration: none;
  text-transform: uppercase;
  width: fit-content;
  margin: 10px auto;
}

.start:hover {
  background-color: #1e20ff;
}

.start:active {
  background-color: #000;
}

li {
  margin-left: 30px;
}

button.inactive-layer {
  background: #eee;
  border: 0;
  padding: 4px;
}
button.active-layer {
  background: #1e9 !important;
  border: 0;
  padding: 4px;
}
button.preview-layer {
  background: #fdd6df;
}
button.inactive-layer:hover {
  background: #1e9;
}

.legend {
  line-height: 18px;
  color: #555;
}
.legend i {
  width: 18px;
  height: 18px;
  display: inline-block;
  margin-right: 8px;
  opacity: 0.7;
}

.diff-add {
  color: green;
}
.diff-remove {
  color: red;
}