*,
*::before,
*::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: monospace, monospace;
}

html {
  -webkit-text-size-adjust: 100%;
  font-size: 62.5%;
  scroll-behavior: smooth;
}

body {
  margin: 0;
  box-sizing: border-box;
  font-size: 1.6rem;
  display: flex;
  justify-content: center;
  align-items: center;
}

main {
  display: block;
}

#container {
  width: 100%;
  max-width: 725px;
  padding: 6px;
  box-sizing: border-box;
  text-align: center;
}

span {
  margin: 0;
  padding: 0;
  display: inline-block;
  line-height: 1.23;
}

pre {
  text-align: left;
  margin: 0;
  overflow-x: hidden
}

h3 {
  font-family: monospace, monospace;
  font-size: 40px;
  margin-bottom: 20px;
}

#content {
  margin: 10px;
}

#cash {
  width: 35%;
  height: 40px;
  padding: 10px;
}

#purchase-btn {
  width: 110px;
  height: 40px;
  cursor: pointer;
  margin-bottom: 15px;
}

#output {
  display: flex;
  justify-content: space-between; 
  align-items: center; 
}

#cash-register {
  flex: 1; 
  margin-right: 20px; 
}

#change-due {
  flex: 1; 
  border: 1px solid #ccc; 
  padding: 10px;
}

#open {
  color: #008000;
}

#closed {
  color: #D30000;
}

a {
  text-decoration: none;
  color: black;
}

@media (max-width: 600px) {
  body {
    font-size: 1.94vw;
  }

  #spade {
    font-size: 4px;
  }

  #cash {
    width: 65%;
  }

  #repo {
    width: 8px;
    height: 8px;
  }

  #github, 
  #linkedin, 
  #facebook, 
  #spotify {
    width: 10px;
    height: 10px;
  }
}

@media (prefers-color-scheme: dark) {
  body {
    background:#121213;
    color:#fff
  }

  .icon {
    color: #fff;
  }
  
  #spade {
    filter: invert(1);
  }
  
  #github, 
  #linkedin, 
  #facebook, 
  #spotify {
    filter: invert(1)
  }
}