* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: 'Inter', sans-serif;
}

body {
  height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(135deg, #0f2027, #203a43, #2c5364);
  color: #fff;
  transition: background 0.3s;
}

.calculator {
  width: 320px;
  background: rgba(255, 255, 255, 0.1);
  backdrop-filter: blur(15px);
  border-radius: 20px;
  padding: 1.5rem;
  box-shadow: 0 0 20px rgba(0,0,0,0.3);
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

header {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

#theme-toggle {
  background: none;
  border: none;
  font-size: 1.3rem;
  cursor: pointer;
  color: #fff;
}

.display {
  background: rgba(255, 255, 255, 0.15);
  padding: 1rem;
  border-radius: 10px;
  text-align: right;
  display: flex;
  flex-direction: column;
  gap: .3rem;
}

#history {
  font-size: 0.8rem;
  opacity: 0.7;
  min-height: 18px;
}

#output {
  font-size: 1.8rem;
  background: transparent;
  border: none;
  outline: none;
  color: #fff;
  text-align: right;
}

.buttons {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 0.6rem;
}

button {
  font-size: 1.1rem;
  padding: 0.8rem;
  border: none;
  border-radius: 10px;
  background: rgba(255,255,255,0.15);
  color: #fff;
  cursor: pointer;
  transition: all 0.2s;
}

button:hover {
  background: rgba(255,255,255,0.3);
  transform: translateY(-2px);
}

.accent {
  background: #00bcd4;
}

.gray {
  background: rgba(255,255,255,0.2);
}

.equals {
  background: #4caf50;
  grid-column: span 1;
}

.wide {
  grid-column: span 2;
}

/* Tema claro */
body.light {
  background: linear-gradient(135deg, #f0f0f0, #d9e4f5);
  color: #000;
}



body.light .calculator {
  background: rgba(255,255,255,0.8);
  color: #000;
}

body.light button {
  color: #000;
}

.light button.btn {
    background: rgb(195, 195, 195);
}

.light .display {
    background: rgb(195, 195, 195);
}