* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: Arial, Helvetica, sans-serif;
    letter-spacing: 1px;
}

body {
    min-height: 100vh;
    max-width: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    background: linear-gradient(45deg, #0a0a0a, #3a4452);
    transition: background 0.5s ease, color 0.5s ease;
}

.calculator {
    padding: 15px;
    box-shadow: 0 0 15px #000;
    border: 2px solid rgb(116, 114, 114);
    border-radius: 15px;
    transition: all 0.5s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-direction: column;
}
/**/
  .calculator-box {
      box-shadow: 0 0 20px rgba(255, 255, 255, 0.5);
      animation: pulse 1s infinite;
  }

  @keyframes pulse {
      0% { box-shadow: 0 0 20px rgba(255, 255, 255, 0.5); }
      50% { box-shadow: 0 0 40px rgba(255, 255, 255, 0.8); }
      100% { box-shadow: 0 0 20px rgba(255, 255, 255, 0.5); }
  }
  
/**/

.display input {
    width: 360px;
    border: none;
    outline: none;
    padding: 20px;
    margin: 10px;
    background: transparent;
    color: #fff;
    font-size: 40px;
    text-align: right;
    cursor: pointer;
    transition: all 0.3s ease;
}

input::placeholder {
    color: #fff;
}

.new-result {
    animation: fadeIn 0.5s ease-in-out;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(-10px); }
    to { opacity: 1; transform: translateY(0); }
}

button {
    width: 70px;
    height: 70px;
    margin: 10px;
    background: rgba(255, 255, 255, 0.1); 
    color: #fff;
    font-size: 22px;
    font-weight: 600;
    border: none;
    border-radius: 50%;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.5);
    outline: none;
    cursor: pointer;
    transition: all 0.2s ease; 
}

button:hover {
    background: rgba(255, 255, 255, 0.2); 
    transform: scale(1.05); 
}

button:active {
    transform: scale(0.95); 
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.5); 
}

.opr {
    color: #fff; 
    background: #30c2cc; 
    font-weight: 700;
}

#eqBtn {
    background: rgba(5, 88, 37, 0.8); 
    font-weight: 900;
}

.opr:hover {
    background: #0c408d; 
}

#eqBtn:hover {
    background: rgba(9, 228, 118, 1); 
}