*{
  margin: 0;
  padding: 0;
  box-sizing: border-box;
 }

 :root{
  --hue:194;
  --bg-color:hsla(var(--hue), 5%, 7%, 1);
  --text-color:hsla(var(--hue), 40%, 98%, 1);
  --primary-color:hsla(var(--hue), 100%, 63%, 1);
  --controls-bg-color:hsla(var(--hue), 0%, 14%);
  --button-secondary:hsla(var(--hue), 40%, 98%, 1);;

  font-size: clamp(40%, 1% + 2vw, 62.5%);
 }

 /* LIGHT/DARK MODE */
 html.light {
  --text-color:hsla(var(--hue), 5%, 7%, 1);
  --bg-color:hsla(var(--hue), 40%, 98%, 1);
 }

 html.light .ph-sun,
 html:not(.light) .ph-moon{
  display: none;
 }

 #toggle-mode {
  position: absolute;
  right: 3.2rem;
  top: 3.2rem;
  font-size: 3.2rem;
  line-height: 0;

  color: var(--text-color);
 }

 .sr-only {
  width: 1px;
  height: 1px;
  position: absolute;
  overflow: hidden;

  margin: -1px;
  padding: 0px;
  border: 0;
  appearance: none; 
 }

 body{
  background: var(--bg-color);
  color: var(--text-color);

  display: grid;
  height: 100vh;
  place-content: center;
 }

 #app{
  display: grid;
  justify-items: center;
 }

 .flex{
  display: flex;
 }

 #timer{
  font-size: 9.6rem;
  font-weight: bold;
  font-family: sans-serif;
 }

 #controls{
  margin-top: 1.6rem;
  padding: 2.2rem 4rem;
  gap: 1.6rem;
  background-color: var(--controls-bg-color);
  border-radius: 999rem;
 }

 button {
  background-color: transparent;
  border: 0;
  color: var(--primary-color);
  cursor: pointer;

  font-size: 6.4rem;
 }

 .secondary{
  color: var(--button-secondary);
 }
 
 /* CONTROLS */
 .running .ph-play-circle,
 .running .ph-timer,
 .music-on .ph-speaker-none,
 html:not(.running) .ph-pause-circle,
 html:not(.running) .ph-stop-circle,
 html:not(.music-on) .ph-speaker-high{
  display: none;
 }