:root {
  --clr-primary-1: hsl(205, 86%, 17%);
  --clr-primary-2: hsl(205, 77%, 27%);
  --clr-primary-3: hsl(205, 72%, 37%);
  --clr-primary-4: hsl(205, 63%, 48%);
  --clr-primary-5: hsl(205, 78%, 60%);
  --clr-primary-6: hsl(205, 89%, 70%);
  --clr-primary-7: hsl(205, 90%, 76%);
  --clr-primary-8: hsl(205, 86%, 81%);
  --clr-primary-9: hsl(205, 90%, 88%);
  --clr-primary-10: hsl(205, 100%, 96%);
  --clr-grey-1: hsl(209, 61%, 16%);
  --clr-grey-2: hsl(211, 39%, 23%);
  --clr-grey-3: hsl(209, 34%, 30%);
  --clr-grey-4: hsl(209, 28%, 39%);
  --clr-grey-5: hsl(210, 22%, 49%);
  --clr-grey-6: hsl(209, 23%, 60%);
  --clr-grey-7: hsl(211, 27%, 70%);
  --clr-grey-8: hsl(210, 31%, 80%);
  --clr-grey-9: hsl(212, 33%, 89%);
  --clr-grey-10: hsl(210, 36%, 96%);
  --clr-white: #fff;
  --clr-red-dark: hsl(360, 67%, 44%);
  --clr-red-light: hsl(360, 71%, 66%);
  --clr-green-dark: hsl(125, 67%, 44%);
  --clr-green-light: hsl(125, 71%, 66%);
  --clr-black: #222;
  --ff-primary: "Roboto", sans-serif;
  --ff-secondary: "Open Sans", sans-serif;
  --transition: all 0.3s linear;
  --spacing: 0.25rem;
  --radius: 0.5rem;
  --light-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
  --dark-shadow: 0 5px 15px rgba(0, 0, 0, 0.2);
  --max-width: 1170px;
  --fixed-width: 620px;
}

body {
  font-family: var(--ff-secondary);
  background: var(--clr-grey-10);
  color: var(--clr-grey-1);
  line-height: 1.5;
  font-size: 1rem;
}
*,
::after,
::before {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}
div {
  display: block;
}

main {
  min-height: 100vh;
  display: grid;
  place-items: center;
}

.container {
  text-align: center;
}

h1 {
  letter-spacing: var(--spacing);
  text-transform: capitalize;
  line-height: 1.25;
  margin-bottom: 0.75rem;
  font-family: var(--ff-primary);
  display: block;
  font-size: 3rem;
  font-weight: bold;
}

#value {
  font-size: 6rem;
  font-weight: bold;
}

.positive {
  color: var(--clr-green-dark);
}

.negative {
  color: var(--clr-red-dark);
}

.btn {
  margin: 0.5rem;
}
.btn:hover {
  color: var(--clr-white);
}

.decrease:hover {
  background-color: var(--clr-red-light);
  border-color: var(--clr-red-dark);
}

.reset:hover {
  background-color: var(--clr-black);
}

.increase:hover {
  background-color: var(--clr-green-light);
  border-color: var(--clr-green-dark);
}