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

:root {
  --color-white: #ffffff;
  --color-black: #0c0d16;
  --color-light-black: #080a1c;
  --color-dark-grey: #35363e;
  --color-green: #2cbb00;
  --color-red: #d10d24;
  --color-light-blue: #5ef2e3;
  --color-light-blue-dark: #4BC2B6;
}

html {
  height: 100%;
  color: var(--color-white);
  font-size: 62.5%;
  line-height: 1.5;
  font-family: Arial, Helvetica, sans-serif;
}

body {
  min-height: 100%;
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 6rem 1.5rem;
  background-color: var(--color-black);
}

input[type="radio"] {
  width: 2.5rem;
  aspect-ratio: 1 / 1;
  cursor: pointer;
}

button {
  border: none;
  outline: none;
  cursor: pointer;
}

.f2d {
  width: min(100%, 55rem);
  background-color: var(--color-dark-grey);
  border-radius: 1rem;
  padding: 1.5rem;
}

.f2d__timers {
  width: 100%;
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.f2d__timer {
  width: 100%;
  background-color: var(--color-black);
  border-radius: 0.8rem;
  padding: 1rem;
  font-size: 11rem;
  line-height: 1;
  font-variant-numeric: tabular-nums;
  font-style: italic;
  font-weight: 600;
  text-align: center;
  letter-spacing: 1.5rem;
}

.f2d__timer-green {
  color: var(--color-green)
}

.f2d__timer-red {
  color: var(--color-red)
}

.f2d__titles {
  margin-top: 1.5rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1.5rem;
}

.f2d__titles p {
  width: 100%;
  display: flex;
  justify-content: center;
  align-items: center;
  font-size: 2rem;
  font-weight: 700;
  padding: 1.5rem;
}

.f2d__settings {
  margin-top: 1.5rem;
  width: 100%;
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 1.5rem;
}

.f2d__setting {
  width: 100%;
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: center;
  gap: 0.5rem;
  flex-grow: 1;
  padding: 0 1rem 1rem;
  border-radius: 0.8rem;
  border: 1px solid var(--color-white);
}

.f2d__setting > div {
  display: flex;
  flex-direction: column;
  align-items: center;
  flex-grow: 1;
  gap: 0.5rem;
}

.f2d__setting legend {
  font-size: 1.4rem;
  font-weight: 600;
  padding: 0 0.5rem;
}

.f2d__setting > div label {
  font-size: 1.2rem;
}

.f2d__enabled {
  background-color: DarkGreen;
}

.f2d__buttons {
  margin-top: 1.5rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
}

.f2d__buttons button {
  width: 100%;
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 1.5rem;
  color: var(--color-light-black);
  font-weight: 600;
  font-size: 1.6rem;
  line-height: 2rem;
  border-radius: 0.8rem;
  user-select: none;
  background-color: var(--color-light-blue);
  box-shadow: 0px 4px 8px rgba(0, 0, 0, 0.1),
    0px 4px 24px rgba(94, 242, 227, 0.1);
}

.preloader {
  position: fixed;
  inset: 0;
  display: flex;
  justify-content: center;
  align-items: center;
  background-color: var(--color-black);
  z-index: 100;
}

.preloader__spinner {
  position: relative;
}

.preloader__spinner::before,
.preloader__spinner::after {
  content: '';
  border-radius: 50%;
  position: absolute;
  transform: translate(-50%, -50%);
}

.preloader__spinner::before {
  width: 2.02rem;
  height: 2.02rem;
  background: var(--color-light-blue);
}

.preloader__spinner::after {
  width: 7.2rem;
  height: 7.2rem;
  animation: spinner 1s infinite linear;
  border: 1.44rem solid var(--color-light-blue);
  border-left-color: transparent;
  border-right-color: transparent;
}

@keyframes spinner {
  to {
    transform: translate(-50%, -50%) rotate(360deg);
  }
}

@media (hover: hover) and (pointer: fine) {
  .f2d__buttons button {
    transition: background-color .3s;
  }

  .f2d__buttons button:hover {
    background-color: var(--color-light-blue-dark);
    transition: background-color .3s;
  }
}

@media (hover: none),
(pointer: coarse) {
  .f2d__buttons button:active {
    background-color: var(--color-light-blue-dark);
  }
}

@media (max-width: 450px) {
  .f2d__timer {
    font-size: 7rem;
  }

  .f2d__titles p {
    font-size: 1.6rem;
  }

  .f2d__settings {
    flex-direction: column;
  }
}

@media (max-width: 350px) {
  .f2d__timer {
    font-size: 5rem;
  }

  .f2d__titles p {
    font-size: 1.4rem;
    padding: 0.5rem;
  }
}