* {
  box-sizing: border-box;
}

body {
  max-width: 40em;
  margin: 0 auto;
  padding: 20px;

  background: #fff;
  color: #000;

  font-family:
    "MS Gothic",
    "MS Mincho",
    monospace;

  line-height: 1.8;
}

main {
  width: 100%;
}

h1,
h2 {
  font-weight: normal;
}

h1 {
  margin: 0;
  font-size: 1.2em;
}

h2 {
  margin: 0 0 0.25em;
  font-size: 1em;
}

section {
  margin: 1.5em 0;
}


canvas {
  display: block;
  width: 100%;
  height: 100px;
  margin: 1em 0 1.5em;
  background: #fff;
}

output {
  display: block;
  margin: 0;
  font-size: 0.9em;
}

button,
input {
  font: inherit;
}

/* range */

input[type="range"] {
  display: block;
  width: 100%;
  height: 20px;
  margin: 0;
  padding: 0;

  appearance: none;
  -webkit-appearance: none;

  border: 0;
  outline: 0;
  background: transparent;

  cursor: pointer;
}

input[type="range"]:focus,
input[type="range"]:focus-visible,
input[type="range"]:active {
  border: 0;
  outline: 0;
  background: transparent;
}

/* Chrome / Edge / Safari */

input[type="range"]::-webkit-slider-runnable-track {
  width: 100%;
  height: 1px;

  border: 0;
  border-radius: 0;

  background: #000;
}

input[type="range"]:focus::-webkit-slider-runnable-track,
input[type="range"]:active::-webkit-slider-runnable-track {
  height: 1px;
  background: #000;
}

input[type="range"]::-webkit-slider-thumb {
  width: 16px;
  height: 16px;
  margin-top: -7.5px;

  appearance: none;
  -webkit-appearance: none;

  border: 5px solid #fff;
  border-radius: 50%;

  background: #000;
}

/* Firefox */

input[type="range"]::-moz-range-track {
  width: 100%;
  height: 1px;

  border: 0;
  border-radius: 0;

  background: #000;
}

input[type="range"]::-moz-range-progress {
  height: 1px;

  border: 0;

  background: #000;
}

input[type="range"]::-moz-range-thumb {
  width: 6px;
  height: 6px;

  border: 5px solid #fff;
  border-radius: 50%;

  background: #000;
}

/* radio */

.wave-group {
  display: flex;
  flex-wrap: wrap;
  gap: 1em;
  margin-top: 0.4em;
}

.wave-group label {
  cursor: pointer;
  user-select: none;
}

.wave-group input[type="radio"] {
  margin: 0 0.2em 0 0;
  accent-color: #000;
}

/* start / stop */

button {
  margin: 0;
  padding: 0.15em 0.6em;

  border: 1px solid #000;
  border-radius: 0;

  background: #fff;
  color: #000;

  cursor: pointer;
}

button:hover {
  background: #000;
  color: #fff;
}

button:focus-visible {
  outline: 1px solid #000;
  outline-offset: 3px;
}