* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  text-decoration: none;
  list-style: none;
}

:root {
  --bg-color: hsl(240, 6%, 21%);
  --text-color: hsl(240, 40%, 98%);
  --card-color: hsl(240, 9%, 89%);
  --card-icon-color: hsl(240, 6%, 21%);
  --primary-color: hsl(194, 97%, 31%);

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

html.light {
  --bg-color: hsl(240, 40%, 98%);
  --text-color: hsl(240, 6%, 21%);
}

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

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

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

#btn-toggle-mode {
  position: absolute;
  top: 3.2rem;
  right: 3.2rem;
  font-size: 3.2rem;
  line-height: 0;
  color: var(--text-color);
  transition: color .3s;
}

#btn-toggle-mode:hover {
  color: var(--primary-color);
}

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

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

button {
  background-color: transparent;
  border: 0;
  color: var(--text-color);
  cursor: pointer;
  font-size: 5.6rem;
}

#app {
  display: flex;
  align-items: center;
  gap: 19.2rem;

  width: 100%;
  max-width: 82rem;
}

#timer {
  display: flex;
  flex-direction: column;
  align-items: center;
  width: 100%;
  max-width: 32rem;
}

#display {
  display: flex;

  color: var(--text-color);
  font-family: 'Roboto', sans-serif;
  font-size: 12rem;
  font-weight: 500;
}

#controls {
  display: flex;
  justify-content: space-between;
  width: 100%;
  max-width: 30rem;
  margin-top: 1.6rem;
}

.ph-play-circle,
.ph-pause-circle {
  color: var(--primary-color);
}

#sounds-buttons {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
  gap: 3.2rem;

  max-width: 33.6rem;
}

.sounds-buttons button {
  background-color: var(--card-color);
  padding: 4.8rem 4.1rem;
  border-radius: 2.4rem;
  font-size: 5.6rem;
  color: var(--card-icon-color);
  transition: all .3s;
}

.sounds-buttons button:hover {
  transform: scale(1.05);
}

.woods .ph-tree,
.rain .ph-cloud-rain,
.coffee-shop .ph-storefront,
.fireplace .ph-fire {
  background-color: var(--primary-color);
  color: var(--card-color);
}

/* Controls */

.running .ph-play-circle {
  display: none;
}

html:not(.running) .ph-pause-circle {
  display: none;
}

/* Responsivo */

@media (max-width: 900px) {
  #app {
    flex-direction: column;
    gap: 9.8rem;
  }
}