:root {
  font-family: Inter, system-ui, Avenir, Helvetica, Arial, sans-serif;
  line-height: 1.5;
  font-weight: 400;

  color-scheme: light dark;
  color: rgba(255, 255, 255, 0.87);
  background-color: #242424;

  font-synthesis: none;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  display: flex;
  place-items: center;
  min-width: 320px;
}

#app {
  max-width: 1280px;
  margin: 0 auto;
  padding: 2rem;
  text-align: center;
}

button {
  border-radius: 8px;
  border: 1px solid transparent;
  padding: 0.6em 1.2em;
  margin: 0.2em;
  font-size: 1.4em;
  font-weight: 500;
  font-family: inherit;
  background-color: #1a1a1a;
  cursor: pointer;
  transition: border-color 0.25s;
}
button:hover {
  border-color: #646cff;
}
button:focus,
button:focus-visible {
  outline: 4px auto -webkit-focus-ring-color;
}

#output {
  display: flex;
  align-items: stretch;
  letter-spacing: .2em;
  margin-bottom: .4em;
}
#display {
  flex-grow: 1;
  text-align: left;
  padding: .25em .75em;
  font-size: 1.5em;
  background-color: #1a1a1a;
  box-shadow: inset -.25rem -.25rem .5rem rgba(0,0,0,.5);
  height: inherit;
}

#light {
  width: 3em;
  height: 3em;
  border-radius: 50%;
  background-color: #1a1a1a;
  margin-left: .75em;
}
#light.is-error {
  background-color: #fd3838;
}
#light.is-success {
  background-color: #46fd46;
}

#keypad {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
}
#keypad > button:last-child {
  grid-column: 2;
}

@media (prefers-color-scheme: light) {
  :root {
    color: #213547;
    background-color: #ffffff;
  }
  #display {
    background-color: #eeeeee;
    box-shadow: inset -.25rem -.25rem .5rem rgba(0,0,0,.1);
  }
  button, #light {
    background-color: #eeeeee;
  }
}
@media (max-width: 480px) {
  #output {
    font-size: 1.6em;
  }
  button {
    font-size: 1.5em;
    padding: 0.8em 1.4em;
    margin: 0.3em;
  }
}