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

html,
body {
  height: 100%;
  font-family: "Pretendard", sans-serif;
  background-color: var(--black);
}

button {
  border: none;
  background: none;
  padding: 0;
  cursor: pointer;
}

/* color variables */
:root {
  --white: #ffffff;
  --gray-100: #eeeeee;
  --gray-200: #dadada;
  --gray-300: #b8b8b8;
  --gray-400: #444444;
  --gray-600: #666666;
  --gray-700: #777777;
  --gray-800: #8c8c8c;
  --black: #222222;
  /* status color */
  --red: #ff5f57;
  --yellow: #ffbd2e;
  --green: #28c840;
}

/* calculator-layout */
.calculator {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
}

.calc-container {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 20px;
  padding: 20px;
  border-radius: 8px;
  border: 2px solid var(--white);
  background-color: var(--gray-100);
  z-index: 100;
}

.calc-shadow {
  position: absolute;
  bottom: 136px;
  width: 384px;
  height: 30px;
  background: var(--gray-300);
  border-radius: 0 0 12px 12px;
  background: linear-gradient(180deg, var(--gray-400) -20%, var(--gray-700) 90%);
}

/* calculator inner */
/* window buttons */
.calc__window-btns {
  display: flex;
  gap: 8px;
}

.calc__window-btn {
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background-position: center;
  background-repeat: no-repeat;
  background-size: 16px;
  background-color: var(--gray-600);
  transition: all 0.2s ease;
}

.calc__window-btn.close:hover {
  background-color: var(--red);
  background-image: url(/calculator/src/images/ico_close.svg);
}

.calc__window-btn.min:hover {
  background-color: var(--yellow);
  background-image: url(/calculator/src/images/ico_min.svg);
}
.calc__window-btn.max:hover {
  background-color: var(--green);
  background-image: url(/calculator/src/images/ico_max.svg);
}

/* display */
.calc__display {
  width: 340px;
  height: 88px;
  display: flex;
  justify-content: flex-end;
  align-items: center;
  padding: 20px;
  font-size: 32px;
  border-radius: 8px;
  color: var(--gray-100);
  background-color: var(--black);
  transition: font-size 0.2s ease;
}

/* buttons */
.calc__buttons {
  width: 100%;
  max-width: 340px;
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
  border-radius: 8px;
  padding: 4px;
  background-color: var(--black);
}

.button {
  display: flex;
  justify-content: center;
  align-items: center;
  font-size: 24px;
  color: var(--gray-600);
  padding: 20px;
  border-radius: 4px;
  background-color: var(--gray-200);
  transition: all 0.2s ease;
}

.button__inner {
  display: flex;
  justify-content: center;
  align-items: center;
  width: 40px;
  height: 40px;
  font-size: 18px;
  border-radius: 50%;
  background: linear-gradient(150deg, var(--gray-300) 20%, var(--gray-100) 60%);
}

.button.zero {
  flex-grow: 1;
}

.button:hover {
  background-color: var(--gray-300);
}

.button:active {
  transform: scale(0.9);
  background-color: var(--gray-800);
  box-shadow: inset 4px 4px 4px rgba(0, 0, 0, 0.4);
}

/* utils */
.a11y-hidden {
  position: absolute;
  overflow: hidden;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  border: 0;
  clip: rect(0, 0, 0, 0);
  clip-path: inset(50%);
  white-space: nowrap;
}