html, body {
  background: #123;
  color: #ddd;
  font-size: 18px;
  margin: 0;
  padding: 0;
  font-family: Helvetica, Roboto;
}
::selection{
  color: black;
  background: plum;
}
main {
  padding: 1rem;
}
h1, h2, h3 {
  margin: 0;
  padding: 0;
}
ul {
  list-style: none;
  padding: 0 1rem;
}
h1 {
  letter-spacing: -3px;
  color: black;
  background: white;
}
#filter {
  position: fixed;
  right: 1rem;
  top: 1rem;
  border: 2px solid #888;
  padding: 0.2rem;
  border-radius: 0.3rem;
}
.form {
  margin-bottom: 2rem;
}
.variable {
  margin-top: 1rem;  
}
.variable > label > * {
  margin-top: 0.5rem;
  flex-grow: 1;
  display: inline-block;
}
.variable .name,
.variable .prefix,
.variable .symbol {
  text-align: right;
  margin: 0 0.1rem;
}
.variable .name {
  width: 10rem;
}
.variable .prefix {
  width: 1.5rem;
}
.variable .symbol {
  font-style: italic;
  font-weight: bold;
  font-family: Serif;
  font-size: 1.2rem;
  width: 1.5rem;
  text-align: right;
  color: white;
}
input, select {
  background: black;
  font-size: inherit;
  font-family: inherit;
  border-radius: 0.2rem;
  border: none;
  color: white;
}
input[type=number] {
  text-align: right;
  width: 5rem;
  font-family: Monospace, monospace;
}
input[name=exponent] {
  transform: translateY(-0.5rem);
  font-size: 0.9rem;
  width: 3rem;
}
input.positive { color: paleturquoise; }
input.zero { color: #888; }
input.negative { color: pink; }
input.invalid { background: maroon; }
select {
  width: 8rem;
}
option {
  text-align: left;
}
a, a:visited {
  color: inherit;
  text-decoration: none;
}
a:hover, a:focus {
  text-decoration: underline;
}
h3 {
  display: inline;
  cursor: pointer;
}
details > p {
  font-family: serif;
  color: #ccc;
}
#credits a {
  font-weight: bold;
}