html {
  box-sizing: border-box;
}

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

:root {
  /* hsl blue */
  --primary-hsl-blue: 200, 100%, 91%;
  --secondary-hsl-blue: 200, 100%, 50%;
  --deep-hsl-blue: 200, 100%, 6%;

  /* color */
  --text-color: #fff;
}

body {
  background-color: hsla(var(--deep-hsl-blue), 0.5);
  color: var(--text-color);
  font-family: Helvetica, sans-serif;
}

div.tip-container {
  background-color: hsla(var(--secondary-hsl-blue), 0.6);
  padding: 1em;
  width: max(90%, 80%);
  height: 60vh;
  margin: 4em auto;
  border: 0.1em solid #3335;
  border-radius: 0.4em;
}

div.bill-container,
div.total-tip,
div.total-person,
div.total-amount {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  padding: 1em;
  gap: 1em;
  align-items: center;
  justify-content: center;
}

div.bill-container input,
div.total-tip input {
  padding: 0.3em;
  outline: none;
  border: 0.08em solid rgb(0, 0, 0, 0.3);
  border-radius: 0.2em;
  background-color: transparent;
  box-shadow: 0 0.3em 0.5em rgb(255, 255, 255, 0.1);
  cursor: pointer;
}

div.bill-container input:focus,
div.total-tip input:focus {
  outline: none;
}

div.total-person button {
  padding: 0.2em 0.4em;
  border: none;
  cursor: pointer;
}

div.total-person span {
  padding: 0.2em;
  display: inline-block;
  width: 2em;
  text-align: center;
  cursor: pointer;
}

div.error {
  position: absolute;
  top: 0;
  right: 0;
  bottom: auto;
  left: 0;
  width: max(80%, 75%);
  margin: 0 auto;
  height: 5em;
  padding: 1em;
  background-color: hsl(var(--secondary-hsl-blue));
  border-radius: 0.3em;
  text-align: center;
}

.hide {
  opacity: 0;
  transform: scale(0);
}

button {
  background-color: hsla(var(--deep-hsl-blue), 0.5);
  color: var(--text-color);
}

div button.close {
  width: 100%;
  border: 0.1em solid rgb(0, 0, 0, 0.3);
  border-radius: 0.3em;
  margin-top: 0.1em;
  cursor: pointer;
}