@import url('https://fonts.googleapis.com/css2?family=Baloo+2&display=swap');

:root {
  --bg: #fff0f5;
  --display-bg: #fff;
  --button-bg: #ffeaf4;
  --button-hover: #ffd6e8;
  --text: #333;
  --equal: #ff8fab;
  --equal-hover: #ff6d8b;
}

body.dark {
  --bg: #2c2c38;
  --display-bg: #3a3a4a;
  --button-bg: #5a5a70;
  --button-hover: #777799;
  --text: #fefefe;
  --equal: #ff709a;
  --equal-hover: #ff4e7a;
}

body {
  margin: 0;
  background: var(--bg);
  font-family: 'Baloo 2', cursive;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  height: 100vh;
  transition: background 0.3s ease;
}

#theme-toggle {
  position: absolute;
  top: 20px;
  right: 20px;
  background: var(--button-bg);
  color: var(--text);
  border: none;
  font-size: 1.5rem;
  padding: 10px 15px;
  border-radius: 50%;
  cursor: pointer;
  transition: background 0.2s;
  box-shadow: 0 4px 10px rgba(0,0,0,0.1);
}

#theme-toggle:hover {
  background: var(--button-hover);
}

.calculator {
  background: var(--display-bg);
  border-radius: 30px;
  box-shadow: 0 12px 30px rgba(0, 0, 0, 0.1);
  width: 330px;
  overflow: hidden;
  padding: 20px;
  transition: background 0.3s ease;
}

.display {
  background: var(--display-bg);
  color: var(--text);
  text-align: right;
  font-size: 2.5rem;
  padding: 1rem;
  border-radius: 20px;
  margin-bottom: 20px;
  font-weight: 600;
  box-shadow: inset 0 0 5px rgba(0,0,0,0.1);
}

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

.btn {
  font-size: 1.4rem;
  padding: 20px;
  border: none;
  border-radius: 15px;
  background: var(--button-bg);
  color: var(--text);
  cursor: pointer;
  transition: all 0.2s ease;
  box-shadow: 0 4px 10px rgba(0, 0, 0, 0.05);
}

.btn:hover {
  background: var(--button-hover);
  transform: translateY(-2px);
}

.equal {
  background: var(--equal);
  color: white;
  grid-row: span 2;
  box-shadow: 0 4px 12px rgba(0,0,0,0.2);
}

.equal:hover {
  background: var(--equal-hover);
}

.zero {
  grid-column: span 2;
}