/* Game shell layout — three-zone layout for every game.
   Requires: theme.css loaded before this file.
   Structure: .shell > .top-bar + .game-area (with .overlay) + .bottom-bar */

/* ── Shell container ── */
.shell {
  display: flex;
  flex-direction: column;
  height: 100dvh;           /* dynamic viewport height — avoids mobile browser chrome overlap */
  overflow: hidden;
}

/* ── Top bar (SHELL-01) ── */
.top-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--shell-top-bar-height);
  padding: 0 8px;
  background-color: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  flex-shrink: 0;
  z-index: 10;
}

.btn-back {
  font-size: 20px;
  min-height: var(--touch-target-min);
  min-width: var(--touch-target-min);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-accent-teal);
  background: none;
  border: none;
  cursor: pointer;
  font-family: inherit;
}

.btn-back:active {
  opacity: 0.7;
}

.game-title {
  font-size: var(--font-size-sm);
  color: var(--color-text);
  text-align: center;
  flex: 1;
  padding: 0 8px;
  overflow: hidden;
  white-space: nowrap;
  text-overflow: ellipsis;
}

.score-display {
  font-size: var(--font-size-sm);
  color: var(--color-accent-amber);
  min-width: 48px;
  text-align: right;
}

/* ── Game area (scrollable, fills remaining space) ── */
.game-area {
  flex: 1;
  overflow-y: auto;
  overflow-x: hidden;
  position: relative;   /* anchor for .overlay absolute positioning */
  background-color: var(--color-bg);
  padding: 16px;
}

/* ── Game-over overlay (SHELL-02) ── */
.overlay {
  position: absolute;
  inset: 0;
  background-color: rgba(26, 26, 46, 0.92);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 16px;
  z-index: 20;
  padding: 24px;
  text-align: center;
}

.overlay[hidden] {
  display: none;
}

.overlay h2 {
  font-size: var(--font-size-lg);
  color: var(--color-accent-red);
  margin-bottom: 8px;
}

.overlay p {
  font-size: var(--font-size-sm);
  color: var(--color-text);
  line-height: 1.6;
}

.overlay .btn-primary {
  background-color: var(--color-accent-teal);
  color: var(--color-bg);
  padding: 12px 24px;
  border-radius: 4px;
  font-family: inherit;
  font-size: var(--font-size-sm);
  min-height: var(--touch-target-min);
  cursor: pointer;
  border: none;
  width: 100%;
  max-width: 240px;
}

.overlay .btn-secondary {
  background-color: transparent;
  color: var(--color-text-muted);
  padding: 12px 24px;
  border-radius: 4px;
  font-family: inherit;
  font-size: var(--font-size-sm);
  min-height: var(--touch-target-min);
  cursor: pointer;
  border: 1px solid var(--color-border);
  width: 100%;
  max-width: 240px;
}

/* ── Bottom controls bar (SHELL-03) ── */
.bottom-bar {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  height: var(--shell-bottom-bar-height);
  padding: 0 16px;
  background-color: var(--color-surface);
  border-top: 1px solid var(--color-border);
  flex-shrink: 0;
}

.bottom-bar button {
  flex: 1;
  max-width: 120px;
  height: calc(var(--shell-bottom-bar-height) - 16px);
  min-height: var(--touch-target-min);
  background-color: var(--color-border);
  color: var(--color-text);
  border-radius: 4px;
  font-family: inherit;
  font-size: var(--font-size-sm);
  cursor: pointer;
  border: none;
}

.bottom-bar button:active {
  opacity: 0.8;
}

/* ── Utility classes ── */
.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
}