style.css

:root {
  --color-background: #080416;
  --color-accent-1: #9ebc20;
  --color-accent-2: #d81f0d;
  --color-accent-3: #F07B13;
  --color-rest: var(--color-accent-1);
  --color-focus: var(--color-accent-2);
}

* {
  -webkit-box-sizing: border-box;
          box-sizing: border-box;
}
html {
  font-family: "Roboto", Helvetica, Arial, sans-serif;
  font-weight: 400;
  font-size: 16px;
  background: var(--color-background);
  overflow: hidden;
}
body {
  margin: 0;
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-align: center;
      -ms-flex-align: center;
          align-items: center;
  -webkit-box-pack: center;
      -ms-flex-pack: center;
          justify-content: center;
  -webkit-box-orient: vertical;
  -webkit-box-direction: normal;
      -ms-flex-direction: column;
          flex-direction: column;
  background-image: url("./images/pomo-king.svg");
  background-position: center center;
  background-repeat: no-repeat;
  background-size: auto 240px;
  -webkit-transition: opacity 0.3s;
  -o-transition: opacity 0.3s;
  transition: opacity 0.3s;
  height: 100vh;
}
body>.timer-diplay {
  font-size: 3.6rem;
  -webkit-transform: translateY(-18%) translateX(-50%);
      -ms-transform: translateY(-18%) translateX(-50%);
          transform: translateY(-18%) translateX(-50%);
  color: #080416;
  font-family: "Roboto Mono", monospace;
  -webkit-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;
  position: absolute;
  top: 50%;
  left: 50%;
}
body>.sound {
  display: none;
}
body>.status_message {
  width: 100%;
  position: absolute;
  bottom: 2rem;
  font-size: 24px;
  font-weight: 700;
  text-transform: uppercase;
  text-align: center;
  -webkit-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;
  color: var(--color-accent-2);
  -webkit-transition: color 0.3s;
  -o-transition: color 0.3s;
  transition: color 0.3s;
  letter-spacing: 0.2em;
  text-align: center;
}
body>.status_message.rest {
  color: var(--color-accent-1);
}
body>.status_message p {
  opacity: 0.5;
  margin: 0;
}
body>.status_message .status {
  font-size: 2em;
  display: block;
}
.enable-sound {
  top: 3rem;
  position: absolute;
  left: 50%;
  color: var(--color-accent-3);
  border: solid 1px var(--color-accent-3);
  padding: 0.25rem 0.5rem;
  border-radius: 4px;
  text-decoration: none;
  -webkit-transform: translateX(-50%);
      -ms-transform: translateX(-50%);
          transform: translateX(-50%);
}
@-webkit-keyframes fadeOut {
  0% {
    opacity: 1;
  }
  50% {
    opacity: 1;
  }
  100% {
    opacity: 0;
  }
}
@keyframes fadeOut {
  0% {
    opacity: 1;
  }
  50% {
    opacity: 1;
  }
  100% {
    opacity: 0;
  }
}
.enable-sound.enabled {
  color: var(--color-accent-1);
  border-color: transparent;
  -webkit-animation: fadeOut 2s ease-in 1 forwards;
          animation: fadeOut 2s ease-in 1 forwards;
}
section.about {
  background: #9ebc20;
  position: absolute;
  left: 0;
  -webkit-transform: translateX(calc(-100% + 1rem));
      -ms-transform: translateX(calc(-100% + 1rem));
          transform: translateX(calc(-100% + 1rem));
  top: 5%;
  height: 90%;
  color: #080416;
  border-radius: 0 1rem 1rem 0;
  padding: 2rem;
  width: 25rem;
  max-width: calc(100vw - 2rem);
  -webkit-transition: all 0.3s ease-out;
  -o-transition: all 0.3s ease-out;
  transition: all 0.3s ease-out;
}
section.about h2 {
  text-transform: uppercase;
  letter-spacing: 0.2em;
}
section.about:hover{
  -webkit-transform: translateX(0);
      -ms-transform: translateX(0);
          transform: translateX(0);
}
section.about p {
  line-height: 1.5;
}
section.about a {
  font-weight: 700;
  text-decoration: none;
  color: inherit;
}
section.about .timer {
  position: absolute;
  bottom: 2rem;
  left: 2rem;
  line-height: 1rem;
}
section.about .timer .timer-diplay {
  font-size: 1.5em;
  font-weight: 700;
  font-family: "Roboto Mono", monospace;
}
section.about .timer .status_message p {
  font-size: 1em;
  font-weight: 700;
  margin: 0;
  text-transform: uppercase;
}
input[type=range]#volume {
  -webkit-appearance: none;
  margin: 0;
  width: 100%;
  max-width: 200px;
}
input[type=range]:focus {
  outline: none;
}
input[type=range]::-webkit-slider-runnable-track {
  width: 100%;
  height: 8px;
  cursor: pointer;
  background: var(--color-background);
  border-radius: 0;
}
input[type=range]::-webkit-slider-thumb {
  height: 24px;
  width: 24px;
  border-radius: 50%;
  background: var(--color-accent-1);
  border: solid 4px var(--color-background);
  cursor: pointer;
  -webkit-appearance: none;
  margin-top: -8px;
}