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

body {
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  background: linear-gradient(120deg, #84fab0 0%, #8fd3f4 100%);
  font-family: 'Arial', sans-serif;
  position: relative;
  overflow: hidden;
}

.wavy-bg {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 1440 320'%3E%3Cpath fill='%23ffffff' fill-opacity='0.1' d='M0,96L48,117.3C96,139,192,181,288,197.3C384,213,480,203,576,197.3C672,192,768,192,864,181.3C960,171,1056,149,1152,160C1248,171,1344,213,1392,234.7L1440,256V320H1392V0H1344V320H1296L1152,0L1056,320H1008H912H864H816L768,0L720,320H672H576L480,0L432,320H384H336L288,0L240,320H192H144L96,0L48,320H0Z'%3E%3C/path%3E%3C/svg%3E");
  background-position: center;
  background-size: cover;
}

.calculator {
  display: grid;
  grid-template-columns: repeat(4, 1.5fr);
  grid-gap: 10px;
  width: 260px;
  padding: 20px;
  border-radius: 20px;
  background: rgba(255, 255, 255, 0.1);
  backdrop-filter: blur(10px);
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1), 0 1px 3px rgba(0, 0, 0, 0.08);
  z-index: 1;
}

#display {
  grid-column: 1/-1;
  background: rgba(255, 255, 255, 0.1);
  border: none;
  border-radius: 10px;
  padding: 10px;
  text-align: right;
  color: #fff;
  font-size: 24px;
  overflow: hidden;
}

.button {
  background: rgba(255, 255, 255, 0.1);
  padding: 10px;
  border-radius: 10px;
  text-align: center;
  cursor: pointer;
  user-select: none;
  color: #fff;
  font-size: 24px;
  transition: background 0.2s ease-in-out;
}

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

#plus {
  grid-row: 5 / span 2;
}
#equals-button {
    grid-column: span 3 ;
}

@media (max-width: 480px) {
  .calculator {
    grid-gap: 5px;
    width: 200px;
    padding: 15px;
  }

  #display {
    font-size: 20px;
  }

  .button {
    font-size: 20px;
  }
}