style.css

@import url("https://fonts.googleapis.com/css2?family=Jost:wght@400;500;600&display=swap");

* {
  font-family: "Jost", sans-serif;
  padding: 0;
  margin: 0;
  box-sizing: border-box;
}

body {
  background: slateblue;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 100dvh;
  color: #222;
}

.container {
  margin-block: auto;
  width: 90%;
  max-width: 480px;
  background-color: #fff;
  padding: 20px;
  box-shadow: 0 10px 15px rgba(0, 0, 0, 0.2);
  border-radius: 10px;
}

.container h1 {
  line-height: 1;
  text-align: center;
}

form#calculator {
  margin-top: 20px;
  display: grid;
  grid-template-columns: repeat(2, auto);
  gap: 10px;
}

form#calculator label {
  display: block;
  font-size: 0.85rem;
  font-weight: 500;
  text-transform: uppercase;
}

form#calculator input,
form#calculator select {
  width: 100%;
  border: 1px solid #ddd;
  padding: 5px 10px;
  border-radius: 5px;
  text-align: center;
  font-size: 1rem;
  outline-color: slateblue;
}

form#calculator button {
  border: none;
  padding: 10px;
  border-radius: 5px;
  font-size: 1rem;
  box-shadow: 0 3px 5px rgba(0, 0, 0, 0.2);
  cursor: pointer;
  color: #fff;
  transition: filter 0.3s;
}

form#calculator button[type="reset"] {
  background: #333;
}

form#calculator button[type="submit"] {
  background: slateblue;
}

form#calculator button:hover {
  filter: brightness(1.25);
}

div#result {
  max-height: 0;
  opacity: 0;
  overflow: hidden;
  transition: max-height 0.3s cubic-bezier(0.76, 0, 0.24, 1),
    opacity 0.3s ease-in-out 0.3s;
}

div#result.show {
  max-height: 500px;
  opacity: 1;
}

.bmr {
  margin-top: 20px;
  display: grid;
  justify-items: center;
  gap: 10px;
}

.bmr span {
  background: rgba(105, 90, 205, 0.15);
  color: slateblue;
  font-size: 0.85rem;
  font-weight: 600;
  padding: 0 10px;
  border-radius: 10px;
}

.bmr h2 {
  font-size: 4rem;
  font-weight: 500;
  line-height: 1;
  color: slateblue;
}

.bmr p {
  color: slategray;
  font-weight: 500;
}

.daily-calories {
  margin-top: 10px;
  border: 1px solid #ddd;
  border-radius: 5px;
}

.daily-calories h3 {
  padding: 5px 10px;
  text-align: center;
  color: slateblue;
}

.activity-levels {
  list-style-type: none;
  border-top: 1px solid #ddd;
}

.activity-levels li {
  padding: 5px 10px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.activity-levels li:nth-child(even) {
  background: rgba(105, 90, 205, 0.05);
}

.activity-levels p {
  line-height: 1.15;
}

.activity-levels .name {
  display: block;
  font-weight: 500;
  color: #333;
}

.activity-levels .desc {
  color: slategray;
}

.activity-levels .value {
  font-weight: 500;
}