#grid {
  border-collapse: collapse;
  margin-bottom: 1em;
}
#grid td {
  padding: 0;
  margin: 0;
  border: 1px solid #bbb;
  width: 2em;
  height: 2em;
  text-align: center;
}

#grid input[type="text"] {
  width: 2em;
  height: 2em;
  text-align: center;
  border: none;
  padding: 0;
  margin: 0;
  font-size: 1.2em;
  background: #fff;
  outline: none;
}

#grid td.thick-left    { border-left:   3px solid #888; }
#grid td.thick-right   { border-right:  3px solid #888; }
#grid td.thick-top     { border-top:    3px solid #888; }
#grid td.thick-bottom  { border-bottom: 3px solid #888; }

.sudoku-container {
  max-width: 22em;
  margin: 2em auto;
  padding: 1em;
  background: var(--pico-surface-background);
  border-radius: 1em;
  box-shadow: 0 2px 8px 0 #0001;
  display: flex;
  flex-direction: column;
  align-items: center;
}

#grid input[type="text"] {
  background: var(--sd-cell-bg);                                                                                                                                                            
  color: var(--sd-cell-color);   
}

[data-theme="dark"] #grid input[type="text"],
@media (prefers-color-scheme: dark) {
  #grid input[type="text"] {
    color: #fff;                /* white text */
    background: #222;           /* dark background */
    border-radius: 0.2em;
    box-shadow: 0 0 0 1px #444;
  }
}