:root {
  --primary-color: #333;
  --background-color: #fff;
  --text-color: #333;
  /* More CSS variables */
}
[data-theme="dark"] {
  --primary-color: #fff;
  --background-color: #333;
  --text-color: #fff;
}
body {
  margin: 0;
  padding: 0;
  font-family: Arial, sans-serif;
  background-color: var(--background-color);
  color: var(--text-color);
}

header {
  background-color: var(--background-color);
  padding: 1rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo img {
  height: 50px;
}

nav ul {
  display: flex;
  list-style: none;
  gap: 2rem;
}

nav a {
  color: var(--text-color);
  text-decoration: none;
  font-weight: bold;
}

/* 계산기 */

.calculator {
  width: 100%;
  max-width: 375px;
  padding: 20px;
  margin: auto;
}

.display {
  background-color: var(--background-color);
  color: var(--text-color);
  font-size: 80px;
  text-align: right;
  padding: 20px;
  min-height: 120px;
  margin-bottom: 20px;
}

.buttons {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 12px;
}

.btn {
  aspect-ratio: 1;
  border-radius: 50%;
  border: none;
  font-size: 30px;
  color: white;
  cursor: pointer;
  transition: filter 0.2s;
}

.btn:active {
  filter: brightness(130%);
}

.btn.zero {
  grid-column: span 2;
  aspect-ratio: 2;
  border-radius: 35px;
}

.btn.gray {
  background-color: #a5a5a5;
  color: black;
}

.btn.orange {
  background-color: #ff9f0a;
}

.btn.dark-gray {
  background-color: #333333;
}