* {
      box-sizing: border-box;
    }

    body {
      font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
      display: flex;
      justify-content: center;
      align-items: center;
      height: 100vh;
      margin: 0;
      background: linear-gradient(to right, #141e30, #243b55);
    }


    .calculator {
  width: 300px;
  margin: 50px auto;
  padding: 20px;
  background-color: #1e1e1e;
  border-radius: 15px;
  box-shadow: 0 0 15px rgba(0,0,0,0.3);
}

.calculator {
  width: 320px;
  margin: 50px auto;
  padding: 20px;
  background-color: #1e1e1e;
  border-radius: 15px;
  box-shadow: 0 0 20px rgba(0, 0, 0, 0.3);
}

#display {
  width: 100%;
  height: 60px;
  margin-bottom: 20px;
  padding: 15px 20px;
  font-size: 24px;
  border: none;
  border-radius: 10px;
  background-color: #f1f1f1;
  box-sizing: border-box;
  text-align: right;
}




    .calculator {
      background: #1f1f2f;
      padding: 25px;
      border-radius: 24px;
      box-shadow: 0 20px 40px rgba(0, 0, 0, 0.4);
      width: 360px;
    }

    .display {
      background: #101019;
      color: #00ffcc;
      font-size: 2.4em;
      text-align: right;
      padding: 25px 20px;
      border-radius: 16px;
      margin-bottom: 25px;
      height: 70px;
      overflow: hidden;
      word-wrap: break-word;
    }

    .buttons {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 15px;
    }

    .btn {
      background: #2e2e3e;
      color: #ffffff;
      padding: 20px;
      border-radius: 16px;
      font-size: 1.3em;
      text-align: center;
      cursor: pointer;
      transition: 0.2s;
      user-select: none;
    }

    .btn:hover {
      background: #00ffcc;
      color: #101019;
    }

    .btn.operator {
      background: #ff6f61;
    }

    .btn.operator:hover {
      background: #ff9671;
    }

    .btn.equal {
      grid-column: span 2;
      background: #00b894;
    }

    .btn.equal:hover {
      background: #00cec9;
    }

    .btn.utility {
      background: #3e3e50;
    }

    .btn.utility:hover {
      background: #77789b;
      color: white;
    }

    /* Modern Glassmorphism Calculator Style */
body {
  min-height: 100vh;
  background: linear-gradient(135deg, #a8edea 0%, #fed6e3 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: 'Segoe UI', 'Roboto', Arial, sans-serif;
  margin: 0;
}

.calculator {
  background: rgba(255, 255, 255, 0.18);
  box-shadow: 0 8px 32px 0 rgba(31, 38, 135, 0.25);
  backdrop-filter: blur(16px);
  border-radius: 28px;
  padding: 36px 28px 28px 28px;
  width: 350px;
  border: 1.5px solid rgba(255,255,255,0.25);
  transition: box-shadow 0.2s;
}

#display {
  width: 100%;
  height: 60px;
  border: none;
  border-radius: 16px;
  margin-bottom: 28px;
  background: rgba(255,255,255,0.7);
  font-size: 2.2rem;
  text-align: right;
  padding: 0 18px;
  box-shadow: 0 2px 12px rgba(0,0,0,0.07);
  outline: none;
  color: #222;
  letter-spacing: 1.5px;
  transition: background 0.2s;
}

.buttons {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 18px;
}

.btn {
  background: rgba(255,255,255,0.55);
  border: none;
  border-radius: 14px;
  font-size: 1.35rem;
  padding: 20px 0;
  cursor: pointer;
  box-shadow: 0 2px 8px rgba(0,0,0,0.06);
  transition: background 0.2s, transform 0.1s, color 0.2s;
  color: #222;
  font-weight: 500;
  user-select: none;
  outline: none;
}

.btn:hover, .btn:active {
  background: rgba(168, 237, 234, 0.85);
  color: #185a9d;
  transform: scale(1.07);
}

.btn.operator {
  background: linear-gradient(135deg, #f7971e 0%, #ffd200 100%);
  color: #fff;
  font-weight: bold;
  box-shadow: 0 2px 12px rgba(247,151,30,0.08);
}

.btn.operator:hover, .btn.operator:active {
  background: linear-gradient(135deg, #ffd200 0%, #f7971e 100%);
  color: #fff;
}

.btn.utility {
  background: linear-gradient(135deg, #f857a6 0%, #ff5858 100%);
  color: #fff;
  font-weight: bold;
  box-shadow: 0 2px 12px rgba(248,87,166,0.08);
}

.btn.utility:hover, .btn.utility:active {
  background: linear-gradient(135deg, #ff5858 0%, #f857a6 100%);
  color: #fff;
}

.btn.equal {
  grid-column: span 4;
  background: linear-gradient(135deg, #43cea2 0%, #185a9d 100%);
  color: #fff;
  font-size: 1.6rem;
  font-weight: bold;
  padding: 22px 0;
  margin-top: 10px;
  box-shadow: 0 4px 18px rgba(24,90,157,0.13);
  letter-spacing: 2px;
}

.btn.equal:hover, .btn.equal:active {
  background: linear-gradient(135deg, #185a9d 0%, #43cea2 100%);
  color: #fff;
}

@media (max-width: 400px) {
  .calculator {
    width: 98vw;
    padding: 16px 4px;
  }
  #display {
    font-size: 1.2rem;
    height: 40px;
  }
  .btn {
    font-size: 1rem;
    padding: 12px 0;
  }
}