html {
 
  }

header {
    height: 100px;
    font-family: 'Rancho';
    font-size: 88px;
    background: #097127;
    color: rgb(175, 207, 167);
    padding: 0,2rem;
    text-align: center;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.26);
    width: 100%;
  }

  body {
 
    margin: 0;
  }
  
#calculator {
    font-family: 'Seven Segment', sans-serif;                                          
    font-size: 30px;
    margin: 1rem auto;
    width: 16rem;
    max-width: 90%;
    border: 1px solid #0c9031;
    border-radius: 10px;
    padding: 1rem;
    color: #023d6d;
  }

#calculator button {
    font: inherit; 
    background: #097127;
    color: white;
    border: 1px solid #097127;
    padding: 0.5rem;
    margin: 0.2rem;
    cursor: pointer;
    width: 70px;
    height: 70px;
  }

  #calculator button:focus {
    outline: none;
  }

#calculator button:hover,
#calculator button:active {
    background: #0c9031;
    
  border-color: #0c9031;
}