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

body {
  background: linear-gradient(135deg, #372c19, #3a3938);
  height: 92vh;
}

h1 {
  text-align: center;
  margin-top: 3rem;
  color: white;
  text-shadow: 0 2px 6px rgba(0, 0, 0, 0.3);
}

.inner-calc-container {
  width: 300px;
  margin-top: 2rem;
  border-radius: 20px;
  background: rgba(255, 255, 255, 0.15);
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.2);
}

.outer-calc-container {
  display: flex;
  justify-content: center;
}

.display-box {
  display: flex;
  justify-content: center;
  margin-top: 1rem;
  margin-bottom: 1rem;
}

input {
  width: 260px;
  height: 2.4rem;
  border-radius: 10px;
  border: none;
  background: rgba(255, 255, 255, 0.2);
  color: #fff;
  font-size: 1.2rem;
  text-align: right;
  padding-right: 10px;
  box-shadow: inset 0 2px 5px rgba(0, 0, 0, 0.2);
}

.calc-buttons {
  display: flex;
  flex-wrap: wrap;
  gap: 2rem;
  margin-top: 1rem;
  margin-bottom: 1rem;
  justify-content: center;
}

.button {
  border: 1px solid black;
  width: 2.7rem;
  height: 2.7rem;
  display: flex;
  justify-content: center;
  align-items: center;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.25);
  border: 1px solid rgba(255, 255, 255, 0.3);
  font-weight: 600;
  font-size: 1rem;
  color: #fff;
  cursor: pointer;
  transition: all 0.2s ease-in-out;
}

.button:hover {
  background: rgba(255, 255, 255, 0.4);
  transform: scale(1.05);
}

#clear {
  background: rgba(255, 0, 0, 0.5);
}

#clear:hover {
  background: rgba(255, 0, 0, 0.7);
}

#plus,
#minus,
#multiply,
#divide,
#perc {
  background: rgba(255, 165, 0, 0.5);
}

#plus:hover,
#minus:hover,
#multiply:hover,
#divide:hover,
#perc:hover {
  background: rgba(255, 165, 0, 0.7);
}

.button:last-child {
  background: rgba(0, 255, 128, 0.5);
}

.button:last-child:hover {
  background: rgba(0, 255, 128, 0.7);
}

#zero {
  width: 7.6rem;
  height: 3rem;
  border-radius: 2rem;
}