/* How to play (Fib, Threes, Turtle), layered on the classic stylesheet.
 * how_to_play.js puts a "?" beside the theme toggle, styled as the toggle,
 * and opens this card over the board, on the page's own ground colour, nearly
 * opaque so the rules stay legible over a full board in both themes. */
.howto-button {
  font-family: inherit;
  font-size: 21px;
  font-weight: 700;
  line-height: 1;
}

.howto {
  position: absolute;
  inset: 0;
  z-index: 110;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-board);
  background: color-mix(in srgb, var(--ground) 95%, transparent);
  animation: fade-in 140ms ease;
}

.howto[hidden] {
  display: none;
}

.howto-card {
  display: flex;
  flex-direction: column;
  gap: 10px;
  max-width: 86%;
  color: var(--ink);
  font-size: 15px;
  line-height: 1.45;
}

.howto-card h2 {
  margin: 0;
  font-size: 22px;
  font-weight: 700;
}

.howto-card p {
  margin: 0;
  font-weight: 400;
}

.howto-card b {
  font-weight: 700;
}

.howto-close {
  align-self: flex-start;
  margin-top: 4px;
  padding: 0 20px;
  border: 0;
  border-radius: 4px;
  background: var(--button);
  color: var(--ink-light);
  font-family: inherit;
  font-size: 15px;
  font-weight: 700;
  line-height: 42px;
  cursor: pointer;
}

.howto-close:focus-visible {
  outline: 3px solid var(--ink);
  outline-offset: 2px;
}