html {
  box-sizing: border-box;
  font-size: 10px;
  background: #8E24AA;
  background: linear-gradient(45deg,hsl(207, 90%, 61%) 0%,hsl(209, 60%, 55%) 50%,hsl(216, 27%, 41%) 100%);
  /* #42a5f5 #478ed1 #0d47a1*/
}

*, *:before, *:after {
  box-sizing: inherit;
}

body {
  margin: 0;
  text-align: center;
  font-family: 'Inconsolata', monospace;
}

.display__time-left {
  font-weight: 100;
  font-size: 20rem;
  margin: 0;
  color: white;
  text-shadow: 4px 4px 0 rgba(0,0,0,0.05);
}

.timer {
  display: flex;
  min-height: 100vh;
  flex-direction: column;
}

.timer__controls {
  display: flex;
}

.timer__controls > * {
  flex: 1;
}

.timer__controls form {
  flex: 1;
  display: flex;
}

.timer__controls input {
  flex: 1;
  border: 0;
  padding: 2rem;
}

.timer__button {
  background: none;
  border: 0;
  cursor: pointer;
  color: white;
  font-size: 2rem;
  text-transform: uppercase;
  background: rgba(0,0,0,0.1);
  border-bottom: 3px solid rgba(0,0,0,0.2);
  border-right: 1px solid rgba(0,0,0,0.2);
  padding: 1rem;
  font-family: 'Inconsolata', monospace;
}

.timer__button:hover,
.timer__button:focus {
  background: rgba(0,0,0,0.2);
  outline: 0;
}

.display {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}

.display__end-time {
  font-size: 4rem;
  color: white;
}

.reset,
.pause {
  background: rgba(0,0,0,0.1);
  border: 2px solid rgba(0,0,0,0.2);
  color: white;
  padding: 1.5rem 3rem;
  font-family: 'Inconsolata', monospace;
  font-size: 3rem;
  margin: 1rem;
  opacity: 0;
  visibility: hidden;
  cursor: pointer;
  transform: translateY(5rem);
  transition: all .3s;
}

.displayReset {
  visibility: visible;
  opacity: 1;
  cursor: pointer;
  transform: translateY(0);
  transition: all 2s;
  transition-timing-function: cubic-bezier(0,1.13,0,1.03);
}

.disablePauseBtn {
  pointer-events: none;
  cursor: not-allowed;
  opacity: .3;
}

#author {
  font-size: 1.2rem;
  color: white;
  position: absolute;
  text-align: center;
  bottom: 1rem;
}

.alertPopup {
  width: 150px;
  position: absolute;
  bottom: 30%;
  right: 2px;
  font-size: 2rem;
  background-color: rgba(255, 255, 255, 0.616);
  padding: 2rem;
  text-align: left;
}

.alertPopup span {
  color: red;
  background-color: rgba(131, 131, 131, 0.555);
  position: absolute;
  top: 0;
  right: 5px;
  padding: .5rem;
  font-size: 2.5rem;
  font-weight: 900;
  cursor: pointer;
}