html, body {
  margin: 0;
  padding: 0;
  width: 100%;
  height: 100%;
  overflow: hidden;
  background: #000;
  color: #9f9;
  font-family: "IBM Plex Mono", "SFMono-Regular", Menlo, monospace;
}

#rain {
  width: 100vw;
  height: 100vh;
  display: block;
}

#controls {
  position: fixed;
  right: 10px;
  top: 10px;
  background: rgba(0, 0, 0, 0.55);
  border: 1px solid rgba(80, 180, 80, 0.4);
  font-size: 12px;
  min-width: 206px;
}

.panel-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  padding: 6px 8px;
  border-bottom: 1px solid rgba(80, 180, 80, 0.25);
}

.panel-title {
  letter-spacing: 0.04em;
}

#panelToggle {
  width: 20px;
  height: 20px;
  line-height: 1;
  padding: 0;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.panel-body {
  display: grid;
  gap: 6px;
  padding: 8px;
}

#controls.collapsed .panel-header {
  border-bottom: 0;
}

#controls.collapsed .panel-body {
  display: none;
}

#controls label {
  display: grid;
  gap: 2px;
}

#controls input,
#controls select,
#controls button {
  background: #0a0a0a;
  color: #9f9;
  border: 1px solid #284;
  font-size: 12px;
}