[계산기 CSS Markup]output 창의 높이관련

안녕하세요.

output 창의 높이가

강사님 화면처럼 고정되지가 않고,

previous 와 current.textContent 값이 있으면 높이가 조금 높아졌다가, 값이 없으면 작아집니다.

계산기의 style.css 를 그대로 따라 했고요.

안되서 강의 파일을 그대로 복사했어도 동일합니다.

당췌 이유를 모르겠습니다. ㅡㅡ;

( 참고로 강의 파일에는 right 로 되어 있어서 botton 으로 수정해서 적용했습니다. )

body {
  height: 100vh;
  background: linear-gradient(to right, #00aaff, #0f4c81);
}

[index.html]

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <link rel="stylesheet" href="style.css" />
    <script src="main.js" defer></script>
    <title>계산기</title>
  </head>
  <body>
    <div class="calculator-grid">
      <div class="output">
        <div class="previous-operand" data-previous-operand></div>
        <div class="current-operand" data-current-operand></div>
      </div>
      <button class="span-two" data-all-clear>AC</button>
      <button data-delete>DEL</button>
      <button data-operation>÷</button>
      <button data-number>1</button>
      <button data-number>2</button>
      <button data-number>3</button>
      <button data-operation>×</button>
      <button data-number>4</button>
      <button data-number>5</button>
      <button data-number>6</button>
      <button data-operation>+</button>
      <button data-number>7</button>
      <button data-number>8</button>
      <button data-number>9</button>
      <button data-operation>-</button>
      <button data-number>.</button>
      <button data-number>0</button>
      <button class="span-two" data-equals>=</button>
    </div>
  </body>
</html>

[style.css]

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

body {
  height: 100vh;
  background: linear-gradient(to bottom, #00aaff, #0f4c81);
}

.calculator-grid {
  display: grid;
  justify-content: center;
  align-content: center;
  min-height: 100vh;
  grid-template-columns: repeat(4, 100px);
  grid-template-rows: minmax(120px, auto) repeat(5, 100px);
}

.calculator-grid > button {
  cursor: pointer;
  font-size: 2rem;
  border: 1px solid #fff;
  outline: none;
  background-color: rgba(255, 255, 255, 0.75);
}

.calculator-grid > button:hover {
  background-color: rgba(255, 255, 255, 0.9);
}

.span-two {
  grid-column: span 2;
}

.output {
  grid-column: 1/-1;
  background-color: rgba(0, 0, 0, 0.75);
  display: flex;
  align-items: flex-end;
  justify-content: space-around;
  flex-direction: column;
  padding: 10px;
  word-wrap: break-word;
  word-break: break-all;
}

.output .previous-operand {
  color: rgba(255, 255, 255, 0.75);
  font-size: 1.5rem;
}

.output .current-operand {
  color: #fff;
  font-size: 2.5rem;
}