style.css

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

.container {
  max-width: 1190px;
  margin: 0 auto;
  padding: 0 10px;
}

.calculator {
  padding: 50px 0;
}

.general-title {
  text-align: center;
  font-size: 40px;
}

@media (max-width: 767px) {
  .calculator {
    padding: 25px 0;
  }

  .general-title {
    font-size: 30px;
  }
}

.calculating-field {
  width: 100%;
  padding: 30px 0 40px 0;
}

.subtitle {
  text-align: center;
  font-size: 25px;
  font-weight: 700;
  margin-top: 30px;
}

@media (max-width: 767px) {
  .calculating-field {
    padding: 15px 0;
  }

  .subtitle {
    font-size: 20px;
    margin-top: 20px;
  }
}

.subtitle:first-child {
  margin-top: 0;
}

.calculating #gender:after {
  content: "";
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  display: block;
  width: 16px;
  height: 16px;
}

.selection-block {
  position: relative;
  display: flex;
  justify-content: center;
  margin: 30px auto 0 auto;
  justify-content: space-between;
}

@media (max-width: 767px) {
  .selection-block {
    margin: 20px auto 0 auto;
  }
}

.choose-item {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 170px;
  height: 50px;
  padding: 0 10px;
  background: #fff;
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
  border: none;
  text-align: center;
  font-size: 14px;
  cursor: pointer;
  outline: 0;
  transition: 0.3s all;
}

@media (max-width: 1000px) {
  .choose-item {
    width: 150px;
  }
}

@media (max-width: 767px) {
  .choose-item {
    height: 42px;
    width: 100px;
  }
}

.choose-item-active {
  color: #fff;
  background-color: #5eb1c0;
}

.inner-input label {
  display: flex;
  justify-content: center;
  padding-bottom: 6px;
  font-size: 15px;
}

.gender-selection {
  max-width: 453px;
}

.parameters-selection {
  max-width: 743px;
}

.parameters-selection .choose-item {
  cursor: default;
}

.activity-selection {
  max-width: 930px;
}

.activity-selection-inner {
  display: contents;
}

@media (max-width: 767px) {
  .activity-selection-inner {
    display: flex;
    flex-direction: column;
  }

  .activity-selection-inner .choose-item:first-child {
    margin-bottom: 10px;
  }
}

@media (max-width: 1000px) {
  .gender-selection {
    max-width: 350px;
  }

  .parameters-selection {
    max-width: 543px;
  }

  .activity-selection {
    max-width: 730px;
  }
}

@media (max-width: 767px) {
  .gender-selection {
    max-width: 250px;
  }

  .parameters-selection {
    max-width: 343px;
  }

  .activity-selection {
    max-width: 216px;
  }
}

.line-divider {
  max-width: 490px;
  height: 1px;
  margin: 40px auto;
  background-color: rgba(0, 0, 0, 0.2);
}

@media (max-width: 767px) {
  .line-divider {
    max-width: 200px;
    margin: 25px auto;
  }
}

.сalories-total-block {
  max-width: 490px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.result {
  font-size: 18px;
  font-weight: 700;
}

.result span {
  font-size: 42px;
}

@media (max-width: 767px) {
  .result {
    font-size: 25px;
  }

  .result span {
    font-size: 25px;
  }
}