* {
  box-sizing: border-box;
}

.page {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  margin: 0;
  height: 100vh;
  overflow: hidden;
  font-family: "Roboto Mono", monospace, Verdana, sans-serif;
  background: linear-gradient(#1b1b1bdc, #e5e6eb);
}

.page__header {
  margin-top: 0;
  margin-bottom: 20px;
  color: #c97cc3;
}

.page__container {
  margin-bottom: 55px;
}

.calc {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  align-items: center;
  flex-shrink: 0;
  gap: 10px;
  border: 2px solid #333;
  border-radius: 10px;
  padding: 35px 20px;
  width: 390px;
  overflow: hidden;
  text-align: center;
  background-color: #c9c9c9;
  box-shadow: 0 1px 10px #4f4f4f;
}

.calc__display {
  margin-bottom: 10px;
  border: 1px solid #444;
  border-radius: 8px;
  padding: 15px;
  width: 330px;
  font-size: 32px;
  text-align: right;
  color: #4f4f4f;
  background-color: #f8f8f8;
  box-shadow: 0 1px 10px #4f4f4f;
}

.calc__btn {
  border: 1px solid #444;
  border-radius: 8px;
  width: 75px;
  height: 75px;
  font-family: "Roboto Mono", monospace, Verdana, sans-serif;
  font-size: 25px;
  color: #fff;
  background-color: #666;
  box-shadow: 0 1px 10px #4f4f4f;
  cursor: pointer;
  transition-property: color, background-color;
  transition-duration: 0.2s;
  transition-timing-function: ease-in-out;
}

.calc__btn:focus-visible:not(:hover) {
  color: #c97cc3;
  background-color: #4f4f4f;
}

.calc__btn:hover:not(:active) {
  color: #c97cc3;
  background-color: #4f4f4f;
}

.calc__btn:active {
  color: #c97cc3;
  background-color: #4f4f4f;
}

.calc__btn_big {
  width: 160px;
  font-size: 30px;
}

.calc__btn_zero {
  font-size: 22px;
}

.calc__btn_colored {
  color: #c97cc3;
  transition: color 0.2s ease-in-out;
}

.calc__btn_colored:focus-visible:not(:hover) {
  color: #fff;
}

.calc__btn_colored:hover:not(:active) {
  color: #fff;
}

.calc__btn_colored:active {
  color: #fff;
}