body {
  background-color: var(--tg-theme-bg-color, #f2f2f2);
  color: var(--tg-theme-text-color, #333);
  font-family: 'Segoe UI', sans-serif;
  text-align: center;
  margin: 0;
  padding: 0;
}

header {
  background: var(--tg-theme-secondary-bg-color, #222);
  color: var(--tg-theme-button-text-color, gold);
  padding: 10px 0;
  box-shadow: 0 2px 6px rgba(0,0,0,0.2);
}

header h1 {
  font-size: 22px;
  margin: 0;
  color: gold;
  font-weight: 700;
}

main {
  margin: 20px auto;
  width: fit-content;
}

#sudoku-board {
  display: grid;
  grid-template-columns: repeat(9, 38px);
  gap: 3px;
  justify-content: center;
  margin: 20px 0;
}

input {
  width: 38px;
  height: 38px;
  text-align: center;
  font-size: 18px;
  border: 1px solid #aaa;
  border-radius: 5px;
  background-color: var(--tg-theme-bg-color, #fff);
  color: var(--tg-theme-text-color, #111);
}

input:disabled {
  background-color: var(--tg-theme-hint-color, #ddd);
  color: #666;
  font-weight: bold;
}

button {
  margin-top: 10px;
  padding: 10px 20px;
  background: var(--tg-theme-button-color, gold);
  color: var(--tg-theme-button-text-color, #000);
  border: none;
  border-radius: 10px;
  font-size: 16px;
  cursor: pointer;
}

button:hover {
  opacity: 0.9;
}

#result {
  margin-top: 15px;
  font-weight: bold;
}

footer {
  margin-top: 30px;
  font-size: 13px;
  color: var(--tg-theme-hint-color, #777);
}