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

@font-face {
  font-family: "space-mono";
  src: url(./font-family/SpaceMono-Bold.ttf);
}

:root {
  /*color*/
  --strong-cyan: hsl(172, 67%, 45%);
  --very-dark-cyan: hsl(183, 100%, 15%);
  --dark-grayish-cyan: hsl(186, 14%, 43%);
  --grayish-cyan: hsl(184, 14%, 56%);
  --light-grayish-cyan: hsl(185, 41%, 84%);
  --very-light-grayish-cyan: hsl(189, 41%, 97%);
  --white: hsl(0, 0%, 100%);
  --red: red;

  /*font size*/
  --font-size-inputs: 2.4rem;

  /*font family*/
  --font-ff-space-mono-bold: "space-Mono";
}

html {
  font-size: 62.5%;
}

body {
  min-height: 100vh;
  font-size: 1.6rem;
  font-family: var(--font-ff-space-mono-bold);
  background-color: var(--light-grayish-cyan);
  display: flex;
  flex-direction: column;
  align-items: center;
}

button {
  border: none;
  font-family: inherit;
}

button,
input,
.tip-button {
  border: none;
  outline: none;
  font-family: inherit;
  border-radius: 8px;
  font-size: 2.4rem;
  color: var(--very-dark-cyan);
}

input[type="number"] {
  color: var(--very-dark-cyan);
  text-align: right;
  width: calc(100% - 1.1rem);
  background-color: transparent;
}

.input-container:hover,
.button-list input.custom-tip:hover {
  outline: 2px solid var(--strong-cyan);
}

/*error message*/
.error {
  color: red;
  text-align: right;
}

.logo {
  display: block;
  margin: 4.9rem auto 4rem;
}

.main {
  border-top-right-radius: 35px;
  border-top-left-radius: 35px;
  max-width: 42rem;
  padding: 3.8rem 3rem 3.2rem;
  background-color: var(--white);
  display: flex;
  flex-direction: column;
}

.label {
  color: var(--dark-grayish-cyan);
  display: block;
}

label[for="bill"] {
  margin-bottom: 1.2rem;
}

.input-container {
  padding: 1rem 1.9rem;
  border-radius: 8px;
  background-color: var(--very-light-grayish-cyan);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.input-container:focus-within {
  outline: 2px solid var(--strong-cyan);
}

/*button list*/
.button-list {
  border-radius: 8px;
  border: none;
  display: grid;
  grid-template-columns: 1fr 1fr;
  grid-gap: 1.5rem;
}

button,
.tip-button {
  background-color: var(--very-dark-cyan);
  color: var(--white);
  text-align: center;
}

.button-list .tip-button:hover {
  --strong-cyan: hsl(172, 67%, 75%);
  background-color: var(--strong-cyan);
  color: var(--very-dark-cyan);
}

button,
.tip-button,
.button-list input.custom-tip {
  padding: 1rem 0;
  width: 100%;
}

.button-list input.custom-tip {
  background-color: var(--very-light-grayish-cyan);
  padding-right: 1.2rem;
  width: 100%;
}

.tip-container {
  margin-top: 3.9rem;
}

.button-list {
  padding-top: 2rem;
}

/*sr-only*/
.sr-only {
  border: 0 !important;
  clip: rect(1px, 1px, 1px, 1px) !important;
  -webkit-clip-path: inset(50%) !important;
  clip-path: inset(50%) !important;
  height: 1px !important;
  margin: -1px !important;
  overflow: hidden !important;
  padding: 0 !important;
  position: absolute !important;
  width: 1px !important;
  white-space: nowrap !important;
}

.tip-button--active {
  background-color: var(--strong-cyan);
  color: var(--very-dark-cyan);
}

.button-list input.custom-tip::placeholder {
  text-align: center;
  color: var(--very-dark-cyan);
  opacity: 0.7;
}

.button-list input.custom-tip:focus {
  outline: 2px solid var(--strong-cyan);
}

input[type="radio"]:focus + .tip-button {
  background-color: var(--strong-cyan);
  color: var(--very-dark-cyan);
}

/*number of people*/
.wrapper {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.number-of-people {
  margin: 3.6rem 0 3.3rem;
}

label[for="no-of-people"] {
  margin-bottom: 0.9rem;
}

/*output*/
.output {
  background-color: var(--very-dark-cyan);
  color: var(--white);
  padding: 5rem 2.5rem 3rem;
  border-radius: 18px;
}

.output__tip {
  margin-bottom: 2rem;
  display: flex;
  justify-content: space-between;
}

.output__label--small {
  font-size: 1.3rem;
  line-height: 0.5;
  color: var(--grayish-cyan);
}

.output__value {
  font-size: 3rem;
  color: var(--strong-cyan);
}

.reset-btn {
  background-color: var(--strong-cyan);
  margin-top: 2rem;
  padding: 1.3rem 0;
  font-size: 2rem;
  text-transform: uppercase;
  color: var(--very-dark-cyan);
}

.reset-btn:hover {
  --strong-cyan: hsl(172, 67%, 75%);
}

/*footer*/
footer {
  margin-top: 1.8rem;
}

.attribution {
  font-size: 11px;
  text-align: center;
}

.attribution a {
  color: hsl(228, 45%, 44%);
}

@media (min-width: 64rem) {
  header {
    margin-top: auto;
  }

  .logo {
    margin-bottom: 8.6rem;
    margin-top: 0;
  }

  .main {
    display: grid;
    grid-template-columns: repeat(2, auto);
    max-width: 91.7rem;
    padding: 3.5rem 3.3rem 3.2rem 4.7rem;
    border-bottom-left-radius: 20px;
    border-bottom-right-radius: 20px;
  }

  .input-for-the-tips {
    margin-top: 1.8rem;
  }

  .input-container {
    padding: 0.8rem 1.9rem;
  }

  .label {
    color: var(--dark-grayish-cyan);
    display: block;

    font-size: 1.8rem;
  }

  .button-list {
    grid-template-columns: repeat(3, 1fr);
  }

  button,
  .button-list input {
    padding: 0.8rem 0;
  }

  .button-list input {
    padding: 0.8rem 0.3rem;
  }

  button {
    font-size: 2.1rem;
  }

  .number-of-people {
    margin: 3.7rem 0 0;
    padding-bottom: 2rem;
  }

  .output {
    margin-left: 4.4rem;
    width: 41.3rem;
    padding: 5.5rem 3.8rem 4.4rem;
    display: flex;
    flex-direction: column;
  }

  .output__tip {
    align-items: center;
    margin-bottom: unset;
  }

  .output__value {
    font-size: 5rem;
  }

  .reset-btn {
    margin-top: auto;
    padding: 1.1rem 0;
    border-radius: 5px;
  }

  footer {
    margin-top: auto;
  }
}

/*utility class*/
.hidden {
  display: none;
}

.margin-top-1 {
  margin-top: 0.5rem;
}

.margin-top-2 {
  margin-top: 2.6rem;
}