/* Pips Game CSS - Updated with placeholder fixes */
/* Version: 2025-01-09 */
/* 棋盘尺寸、配色与阴影等的根级主题变量 */
:root {
  color-scheme: light;
  --tile-size: 68px;
  --board-cell-size: calc(var(--tile-size) + 8px);
  --board-padding: 18px;
  --bg-body: #f6f8ff;
  --surface: #ffffff;
  --surface-muted: rgba(47, 59, 82, 0.05);
  --surface-soft: #f1f4fc;
  --placeholder-fill: var(--surface-soft);
  --placeholder-border: rgba(71, 85, 105, 0.35);
  --text-primary: #2c3142;
  --text-secondary: #62697a;
  --accent: #3c6ff5;
  --accent-strong: #274ed6;
  --accent-soft: rgba(60, 111, 245, 0.14);
  --neutral-border: rgba(109, 120, 143, 0.28);
  --shadow-soft: 0 20px 32px rgba(36, 48, 68, 0.12);
  --shadow-medium: 0 26px 46px rgba(32, 45, 66, 0.16);
  --domino-outline: rgba(0, 0, 0, 0.38);
}

/* Dark theme variables */
body.dark-mode {
  color-scheme: dark;
  --bg-body: #0f172a;
  --surface: #111827;
  --surface-muted: rgba(255, 255, 255, 0.03);
  --surface-soft: #0b1220;
  --placeholder-fill: rgba(148, 163, 184, 0.16);
  --placeholder-border: rgba(148, 163, 184, 0.32);
  --text-primary: #e5e7eb;
  --text-secondary: #cbd5e1;
  --accent: #60a5fa;
  --accent-strong: #3b82f6;
  --accent-soft: rgba(96, 165, 250, 0.16);
  --neutral-border: #334155;
  --shadow-soft: 0 18px 32px rgba(0, 0, 0, 0.35);
  --shadow-medium: 0 24px 42px rgba(0, 0, 0, 0.45);
  --domino-outline: rgba(255, 255, 255, 0.42);
}

/* 统一设置 box-sizing 以保持布局可控 */
* {
  box-sizing: border-box;
}

/* 页面主体的基础排版与背景 */
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  background:
    radial-gradient(circle at 18% 18%, rgba(240, 240, 240, 0.18), transparent 60%),
    radial-gradient(circle at 82% 12%, rgba(255, 255, 255, 0.2), transparent 62%),
    var(--bg-body);
  color: var(--text-primary);
  -webkit-font-smoothing: antialiased;
  letter-spacing: -0.01em;
}

/* Dark mode */
body.dark-mode {
  background: #0f172a;
  color: #e5e7eb;
}

body.dark-mode main {
  color: #e5e7eb;
}

body.dark-mode .page-header,
body.dark-mode .board-container,
body.dark-mode .tray-container,
body.dark-mode .tray,
body.dark-mode .modal {
  background: var(--surface);
  color: var(--text-primary);
  border-color: var(--neutral-border);
}

/* Keep board area aligned with page background in dark mode */
body.dark-mode .board-container {
  background: transparent;
}

body.dark-mode .board {
  background: transparent;
}

body.dark-mode .cell {
  border-color: transparent;
  background: var(--surface-soft);
}

body.dark-mode .tray-hint {
  color: var(--text-secondary);
}

body.dark-mode .theme-toggle-bar {
  background: var(--surface);
  border-color: var(--neutral-border);
}

body.dark-mode .toolbar-btn,
body.dark-mode .difficulty-chip-option,
body.dark-mode .language-trigger {
  background: var(--surface);
  color: var(--text-primary);
  border-color: var(--neutral-border);
}

body.dark-mode .difficulty-chip {
  background: var(--surface);
  border-color: var(--neutral-border);
}

body.dark-mode .difficulty-chip-option {
  background: transparent;
  color: var(--text-secondary);
}

body.dark-mode .difficulty-chip-option:hover {
  background: var(--surface-muted);
  color: var(--text-primary);
}

body.dark-mode .difficulty-chip-option.active {
  background: var(--accent-strong);
  color: #ffffff;
  box-shadow: 0 0 0 1px rgba(96, 165, 250, 0.35) inset;
}

body.dark-mode .toolbar-btn.primary {
  background: var(--accent-strong);
  border-color: var(--accent-strong);
  color: #e5e7eb;
}

body.dark-mode #new-btn,
body.dark-mode #new-btn:hover,
body.dark-mode #new-btn:active {
  background: var(--accent);
  color: #f8fafc;
  border-color: var(--accent-strong);
  box-shadow: none;
}

body.dark-mode #answer-btn,
body.dark-mode #answer-btn:hover,
body.dark-mode #answer-btn:active {
  background: color-mix(in srgb, var(--accent) 60%, #0f172a 40%);
  color: #f8fafc;
  border-color: var(--accent-strong);
  box-shadow: none;
}

body.dark-mode .toast {
  background: var(--surface);
  color: var(--text-primary);
  border-color: var(--neutral-border);
}

/* Region styling in dark mode */
body.dark-mode .cell.region-cell {
  background: var(--region-fill, #2d3748) !important;
  box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.04) !important;
  border-color: var(--region-border-color, #475569) !important;
}
body.dark-mode .cell.region-cell.no-indicator {
  background: var(--region-fill, #2d3748) !important;
  border-color: var(--region-border-color, #475569) !important;
}
body.dark-mode .indicator {
  filter: brightness(0.8);
  color: #f8fafc;
}
body.dark-mode .indicator .indicator-text {
  color: #f8fafc;
}
body.dark-mode .indicator .indicator-icon {
  color: #f8fafc;
}

/* Buttons hover */
body.dark-mode .toolbar-btn:hover,
body.dark-mode .difficulty-chip-option:hover,
body.dark-mode .language-trigger:hover {
  background: var(--surface-muted);
  border-color: var(--neutral-border);
}

/* Domino die styling */
body.dark-mode .domino-content {
  background: var(--surface);
  border-color: var(--domino-outline);
}
body.dark-mode .die-face {
  background: transparent;
}
body.dark-mode .pip {
  background: #f8fafc;
}

/* How to Play & FAQ sections */
body.dark-mode .rules,
body.dark-mode .faq,
body.dark-mode .faq-content {
  background: var(--surface);
  color: var(--text-primary);
  border-color: var(--neutral-border);
}
body.dark-mode .rules h2,
body.dark-mode .faq h2,
body.dark-mode .faq h3 {
  color: var(--text-primary);
}
body.dark-mode .rules p,
body.dark-mode .faq p,
body.dark-mode .faq li {
  color: var(--text-secondary);
}
body.dark-mode .rules .rule-highlight {
  color: var(--accent);
}

/* 左上角的谜题信息徽章 */
.puzzle-meta {
  align-self: flex-start;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 16px;
  border-radius: 16px;
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(14px);
  color: var(--accent-strong);
  font-weight: 600;
  font-size: 0.95rem;
  border: 1px solid rgba(109, 120, 143, 0.22);
  box-shadow: 0 14px 26px rgba(32, 45, 66, 0.16);
  letter-spacing: -0.005em;
}
.puzzle-meta strong {
  font-weight: 700;
}

/* 限制主体内容的宽度与内边距 */
main {
  max-width: 1180px;
  margin: 0 auto;
  padding: 48px 24px 92px;
}

/* 主标题样式 */
h1 {
  margin: 0;
  font-size: 1.9rem;
  font-weight: 700;
  color: #3b4260;
  line-height: 1.2;
}

/* Brand headline styling for primary and secondary title lines */
.headline-brand {
  display: block;
  font-size: clamp(2.2rem, 4vw, 2.8rem);
  font-weight: 800;
  letter-spacing: -0.03em;
}

.headline-tagline {
  display: block;
  margin-top: 6px;
  font-size: clamp(1.1rem, 2.6vw, 1.35rem);
  font-weight: 600;
  color: var(--accent-strong);
  letter-spacing: 0.01em;
}

/* 通用段落样式 */
p {
  line-height: 1.65;
  margin: 12px 0 0;
  color: var(--text-secondary);
}

/* 页眉布局容器 */
.page-header {
  display: flex;
  flex-direction: column;
  gap: 24px;
  margin-bottom: 40px;
}

/* 计时器、控制按钮与分享区域 */
.utility-bar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 18px;
  flex-wrap: nowrap;
  width: 100%;
  min-width: 0;
}

.utility-left {
  display: inline-flex;
  align-items: center;
  gap: 14px;
  flex: 0 0 auto;
  min-width: 0;
  margin-right: auto;
}

.utility-left .timer {
  white-space: nowrap;
}

.utility-right {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 16px;
  flex: 1 1 auto;
  min-width: 0;
  background: transparent;
  border-radius: 0;
  box-shadow: none;
}


.language-switcher {
  position: relative;
  display: inline-flex;
}

.language-trigger {
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.language-trigger[aria-expanded="true"] {
  box-shadow: 0 14px 24px rgba(32, 45, 66, 0.2);
}

.language-icon svg {
  width: 1.2rem;
  height: 1.2rem;
  display: block;
}

.language-menu {
  position: absolute;
  left: 0;
  top: calc(100% + 10px);
  list-style: none;
  margin: 0;
  padding: 8px;
  background: rgba(255, 255, 255, 0.98);
  border: 1px solid rgba(109, 120, 143, 0.18);
  border-radius: 14px;
  box-shadow: 0 18px 32px rgba(35, 48, 68, 0.18);
  display: none;
  min-width: 160px;
  z-index: 150;
}

.language-menu.language-menu-open {
  display: block;
}

.language-menu li {
  margin: 0;
}

.language-menu a {
  display: block;
  padding: 8px 12px;
  border-radius: 10px;
  color: var(--text-primary);
  font-weight: 600;
  text-decoration: none;
  transition: background 0.2s ease;
}

.language-menu a:hover {
  background: rgba(60, 111, 245, 0.12);
}

/* 计时文本样式 */
.timer {
  font-weight: 600;
  font-size: 1.05rem;
  color: var(--text-primary);
  font-variant-numeric: tabular-nums;
}

.timer span {
  display: inline-block;
  min-width: 3.6ch;
}

/* 难度与操作按钮容器 */
.controls {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 14px;
  flex-wrap: nowrap;
  flex: 1 1 auto;
  min-width: 0;
  overflow-x: visible;
  background: transparent;
}

.control-toolbar {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  flex-wrap: nowrap;
  flex: 0 1 auto;
  min-width: 0;
  overflow-x: visible;
  scrollbar-width: none;
  background: transparent;
}

.control-toolbar::-webkit-scrollbar {
  display: none;
}

.toolbar-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  border: none;
  border-radius: 16px;
  padding: 8px 16px;
  background: #eef2fb;
  color: #344771;
  font-weight: 600;
  font-size: 0.9rem;
  cursor: pointer;
  box-shadow: 0 10px 22px rgba(36, 72, 142, 0.14);
  transition: transform 0.18s ease, box-shadow 0.18s ease, background-color 0.2s ease, color 0.2s ease;
  flex: 0 0 auto;
  min-width: 68px;
}

.toolbar-btn:hover {
  transform: translateY(-1px);
  box-shadow: 0 16px 30px rgba(36, 72, 142, 0.2);
  background: #e8e8e8;
}

.toolbar-btn:active {
  transform: translateY(0);
  /* box-shadow: 0 8px 18px rgba(36, 72, 142, 0.18); */
}

.toolbar-btn.primary {
  background: var(--accent);
  color: #ffffff;
  /* box-shadow: 0 14px 28px rgba(188, 204, 242, 0.28); */
}

.toolbar-btn.primary:hover {
  background: #2f5dd8;
}

.toolbar-btn[data-role="language"] {
  background: #e6f3ff;
  color: #0f5688;
  /* box-shadow: 0 12px 24px rgba(15, 86, 136, 0.18); */
}

.toolbar-btn[data-role="language"]:hover {
  background: #d9ecff;
}

.toolbar-btn[data-role="reset"] {
  background: #edeaff;
  color: #4d3fb6;
  /* box-shadow: 0 12px 24px rgba(77, 63, 182, 0.2); */
}

.toolbar-btn[data-role="reset"]:hover {
  background: #e0dcff;
}

#answer-btn {
  background: #f8edd9;
  color: #8a5d1d;
  /* box-shadow: 0 12px 24px rgba(138, 93, 29, 0.18); */
}

#answer-btn:hover {
  background: #f3e1c2;
}

#new-btn {
  background: #e2f5ff;
  color: #2a74b0;
  /* box-shadow: 0 12px 24px rgba(138, 93, 29, 0.18); */
}

#new-btn:hover {
  background: #c7ecff;
  /* box-shadow: 0 12px 24px rgba(138, 93, 29, 0.18); */
}

#new-btn:active {
  background: #e2f5ff;
  /* box-shadow: 0 12px 24px rgba(138, 93, 29, 0.18); */
}

.toolbar-btn.ghost {
  background: #e8f5f2;
  color: #236c55;
  /* box-shadow: 0 10px 22px rgba(35, 108, 85, 0.16); */
}

.toolbar-btn.ghost:hover {
  background: #ddf0eb;
}

.toolbar-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 1.25rem;
  height: 1.25rem;
}

.toolbar-icon svg {
  width: 100%;
  height: 100%;
}

.toolbar-text {
  white-space: nowrap;
}

.difficulty-chip {
  display: inline-flex;
  padding: 4px;
  gap: 6px;
  border-radius: 999px;
  border: 1px solid rgba(0, 0, 0, 0.18);
  background: rgba(178, 178, 178, 0.08);
  flex: 0 1 auto;
  min-width: 0;
}

.difficulty-chip-option {
  border: none;
  background: transparent;
  color: var(--text-secondary);
  font-weight: 600;
  padding: 6px 16px;
  border-radius: 999px;
  cursor: pointer;
  transition: background-color 0.2s ease, color 0.2s ease, box-shadow 0.2s ease;
  flex: 1 1 auto;
  min-width: 0;
}

.difficulty-chip-option:hover {
  background: rgba(60, 111, 245, 0.12);
  color: var(--accent-strong);
}

.difficulty-chip-option.active {
  background: var(--accent);
  color: #ffffff;
  /* box-shadow: 0 14px 22px rgba(60, 111, 245, 0.28); */
}

.toolbar-btn:focus-visible,
.difficulty-chip-option:focus-visible {
  outline: 3px solid rgba(60, 111, 245, 0.32);
  outline-offset: 3px;
}

@media (max-width: 720px) {
  .controls {
    flex-direction: column;
    align-items: stretch;
    gap: 12px;
  }

  .control-toolbar {
    flex-wrap: nowrap;
    justify-content: space-between;
    width: 100%;
  }

  .toolbar-btn {
    flex: 1 1 auto;
    min-width: 48px;
    justify-content: center;
  }

  .toolbar-text {
    display: none;
  }

  .difficulty-chip {
    width: 100%;
    justify-content: space-between;
  }

  .difficulty-chip-option {
    flex: 1 1 0;
    padding: 6px 0;
  }
}

/* 主要操作按钮样式 */
button.action {
  border: none;
  border-radius: 18px;
  padding: 9px 24px;
  font-weight: 600;
  font-size: 0.95rem;
  cursor: pointer;
  transition: transform 0.18s ease, box-shadow 0.18s ease, background-color 0.2s ease, color 0.2s ease;
  background: var(--accent);
  color: #ffffff;
  box-shadow: 0 14px 24px rgba(60, 111, 245, 0.28);
}

/* 主要按钮悬停状态 */
button.action:hover {
  transform: translateY(-1px);
  box-shadow: 0 18px 30px rgba(60, 111, 245, 0.34);
}

/* 主要按钮按下状态 */
button.action:active {
  transform: translateY(0);
  box-shadow: 0 10px 20px rgba(60, 111, 245, 0.26);
}

/* 次级按钮样式 */
button.action.secondary {
  background: rgba(60, 111, 245, 0.1);
  color: var(--accent-strong);
  box-shadow: none;
  border: 1px solid rgba(60, 111, 245, 0.28);
}

/* 次级按钮悬停状态 */
button.action.secondary:hover {
  background: rgba(60, 111, 245, 0.15);
  box-shadow: none;
  color: var(--accent-strong);
}

/* 次级按钮按下状态 */
button.action.secondary:active {
  background: rgba(60, 111, 245, 0.22);
}

/* 键盘导航的聚焦描边 */
button.action:focus-visible {
  outline: 3px solid rgba(60, 111, 245, 0.32);
  outline-offset: 3px;
}

/* 排列棋盘、托盘与提示信息 */
.board-area {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 28px;
}

/* 棋盘容器包裹棋盘与描边图层 */
.board-container {
  display: flex;
  justify-content: center;
  padding: calc(var(--board-padding) + 20px);
  background: transparent;
  border-radius: 26px;
  border: none;
  box-shadow: none;
  width: 100%;
  max-width: 100%;
  overflow-x: auto;
  overflow-y: hidden;
  -webkit-overflow-scrolling: touch;
}

.board-wrapper {
  position: relative;
  display: inline-block;
  min-width: min-content;
  flex: 0 0 auto;
}

.board-spacer {
  flex: 0 0 0px;
}

@media (max-width: 720px) {
  .board-container {
    justify-content: flex-start;
  }
}

/* 棋盘的 CSS 网格布局 */
.board {
  display: grid;
  grid-template-columns: repeat(var(--cols), var(--board-cell-size));
  grid-auto-rows: var(--board-cell-size);
  gap: 4px;
  background: transparent;
  border-radius: 16px;
  position: relative;
}

/* ARIA row container - transparent wrapper for accessibility */
.board-row {
  display: contents;
}

.puzzles-loading .board {
  min-height: calc(var(--board-cell-size) * 7 + 24px);
}

.domino-overlay {
  position: absolute;
  inset: 0;
  pointer-events: none;
  z-index: 50;
}

.domino-outline {
  position: absolute;
  border-radius: 20px;
  border: 4px solid var(--domino-outline);
  background: transparent;
  box-shadow: 0 16px 26px rgba(32, 45, 66, 0.18), inset 0 0 0 1px rgba(255, 255, 255, 0.6);
  z-index: 50;
}

.domino-outline-horizontal {
  border-radius: 10px;
}

.domino-outline-vertical {
  border-radius: 10px;
}

/* 基础格子样式（用于可放置区域） */
.cell {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  width: var(--board-cell-size);
  height: var(--board-cell-size);
  background: rgba(255, 255, 255, 0.94);
  border: 1px solid rgba(205, 208, 220, 0.7);
  font-size: 26px;
  font-weight: 700;
  color: var(--text-primary);
  transition: transform 0.12s ease, box-shadow 0.12s ease, background-color 0.12s ease;
  cursor: pointer;
  border-radius: 2px;
}

/* 区域特定配色 */
.cell.region-cell:not(.no-indicator) {
  background: var(--region-fill, rgba(255, 255, 255, 0.95));
  border-color: rgba(71, 85, 105, 0.18);
}

.cell.cell-neutral {
  background: var(--placeholder-fill);
  border-color: var(--placeholder-border);
  box-shadow: inset 0 1px 4px rgba(15, 23, 42, 0.08);
}

.cell.cell-neutral:hover {
  box-shadow: inset 0 0 0 2px rgba(71, 85, 105, 0.3);
}

/* 没有菱形图标的单个格子 - 与托盘骨牌颜色一致 */
.cell.region-cell.no-indicator {
  background: var(--placeholder-fill) !important;
  border-color: var(--placeholder-border) !important;
  box-shadow: inset 0 1px 4px rgba(15, 23, 42, 0.1) !important;
  color: var(--text-primary);
  border-radius: 8px !important;
}

.cell.region-cell.no-indicator:hover {
  box-shadow: inset 0 0 0 2px rgba(71, 85, 105, 0.4) !important;
}

.cell.region-cell.no-indicator .die-face {
  background: transparent;
}

/* 区域使用虚线边框分割 */
.cell.region-cell.region-border-top {
  border-top: 3px dashed var(--region-border-color);
}
.cell.region-cell.region-border-right {
  border-right: 3px dashed var(--region-border-color);
}
.cell.region-cell.region-border-bottom {
  border-bottom: 3px dashed var(--region-border-color);
}
.cell.region-cell.region-border-left {
  border-left: 3px dashed var(--region-border-color);
}

@media (max-width: 600px) {
  .cell.region-cell.region-border-top {
    border-top-width: 2px;
  }
  .cell.region-cell.region-border-right {
    border-right-width: 2px;
  }
  .cell.region-cell.region-border-bottom {
    border-bottom-width: 2px;
  }
  .cell.region-cell.region-border-left {
    border-left-width: 2px;
  }
}

/* 移除占位格的虚线边框（必须在区域边框规则之后，以确保优先级） */
.cell.region-cell.no-indicator.region-border-top {
  border-top: 1px solid rgba(71, 85, 105, 0.35) !important;
}
.cell.region-cell.no-indicator.region-border-right {
  border-right: 1px solid rgba(71, 85, 105, 0.35) !important;
}
.cell.region-cell.no-indicator.region-border-bottom {
  border-bottom: 1px solid rgba(71, 85, 105, 0.35) !important;
}
.cell.region-cell.no-indicator.region-border-left {
  border-left: 1px solid rgba(71, 85, 105, 0.35) !important;
}

/* 区域完成时改为实线边框 */
.cell.region-cell.region-satisfied:not(.no-indicator) {
  background: var(--region-fill, rgba(255, 255, 255, 0.95));
  box-shadow: none;
}

/* 确保占位格的背景不被覆盖 */
.cell.region-cell.region-satisfied.no-indicator {
  background: var(--surface-soft) !important;
  box-shadow: inset 0 1px 4px rgba(15, 23, 42, 0.08) !important;
}

/* 格子悬停高亮 */
.cell:hover {
  /* background: rgba(255, 255, 255, 0.98); */
  box-shadow: inset 0 0 0 2px rgba(60, 111, 245, 0.2);
}

/* 有骨牌时的格子高亮 */
/* .cell.occupied {
  box-shadow: inset 0 0 0 2px rgba(6, 8, 15, 0.28);
} */

/* 区域不满足条件时的错误高亮 */
/* .cell.region-error {
  box-shadow: inset 0 0 0 4px rgba(225, 83, 64, 0.85);
} */

/* 骨牌预览投影高亮 */
.cell-drop-preview,
.cell-drop-preview-invalid {
  box-shadow: inset 0 0 0 3px rgba(60, 111, 245, 0.38);
  background: rgba(60, 111, 245, 0.18);
}

/* 骨牌预览的非法状态 */
.cell-drop-preview-invalid {
  box-shadow: inset 0 0 0 3px rgba(225, 83, 64, 0.75);
  background: rgba(225, 83, 64, 0.12);
}

.cell.domino-selected {
  cursor: grab;
}

.domino-outline-selected {
  border-color: rgba(60, 111, 245, 0.85);
  box-shadow: 0 14px 28px rgba(36, 58, 110, 0.22), inset 0 0 0 1px rgba(255, 255, 255, 0.45);
}

/* 区域悬停效果 - 使用区域颜色变深 */
.cell.region-hover {
  filter: brightness(0.90) saturate(1.8);
  transition: filter 0.2s ease;
}

.cell.region-hover:hover {
  box-shadow: none;
}

body.dark-mode .cell.region-hover {
  filter: brightness(0.90) saturate(1.8);
}

/* 无效格子不可见且不可操作 */
.cell-void {
  background: transparent;
  border: none;
  cursor: default;
  pointer-events: none;
}

/* 强制深色模式下区域保留本色调（避免后续规则覆盖） */
body.dark-mode .cell {
  background: var(--surface-soft) !important;
  border-color: transparent !important;
}
body.dark-mode .cell.region-cell {
  background: var(--region-fill, #2d3748) !important;
  box-shadow: none !important;
  border-color: var(--region-border-color, #475569) !important;
}
body.dark-mode .cell.region-cell.no-indicator {
  background: var(--placeholder-fill) !important;
  border-color: var(--placeholder-border) !important;
  box-shadow: none !important;
}

/* Dark mode: make colored region borders bolder & more vivid (keep dashed region boundaries) */
body.dark-mode .cell.region-cell:not(.no-indicator) {
  border-width: 2px !important;
  border-style: solid !important;
  border-color: var(--region-border-color, #60a5fa) !important;
  box-shadow: 0 0 0 1px var(--region-border-color, #60a5fa) inset !important;
}

body.dark-mode .cell.region-cell:not(.no-indicator).region-border-top {
  border-top-width: 4px !important;
  border-top-style: dashed !important;
  border-top-color: var(--region-border-color, #60a5fa) !important;
}
body.dark-mode .cell.region-cell:not(.no-indicator).region-border-right {
  border-right-width: 4px !important;
  border-right-style: dashed !important;
  border-right-color: var(--region-border-color, #60a5fa) !important;
}
body.dark-mode .cell.region-cell:not(.no-indicator).region-border-bottom {
  border-bottom-width: 4px !important;
  border-bottom-style: dashed !important;
  border-bottom-color: var(--region-border-color, #60a5fa) !important;
}
body.dark-mode .cell.region-cell:not(.no-indicator).region-border-left {
  border-left-width: 4px !important;
  border-left-style: dashed !important;
  border-left-color: var(--region-border-color, #60a5fa) !important;
}

/* Darken region fills in dark mode without altering pip contrast */
body.dark-mode .cell.region-cell:not(.no-indicator)::before {
  content: '';
  position: absolute;
  inset: 0;
  background: rgba(15, 23, 42, 0.45);
  pointer-events: none;
  border-radius: inherit;
}

/* Hover state: slightly reduce the overlay for feedback */
body.dark-mode .cell.region-cell.region-hover {
  filter: none;
}
body.dark-mode .cell.region-cell:not(.no-indicator).region-hover::before {
  background: rgba(15, 23, 42, 0.30);
}
body.dark-mode .cell-void {
  background: transparent !important;
  border: none !important;
}

/* 悬浮的区域指标菱形 - 在独立容器中，始终在最上层 */
.region-indicator {
  position: absolute;
  width: 35px;
  height: 35px;
  transform: rotate(45deg);
  border-radius: 10px;
  border: 2px solid var(--indicator-color);
  background: rgba(255, 255, 255, 0.92);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--indicator-color);
  font-size: 16px;
  font-weight: 700;
  pointer-events: none;
  box-shadow: 0 8px 16px rgba(32, 45, 66, 0.18);
  z-index: 100;
}

/* 指示文字反向旋转以保持水平 */
.region-indicator .indicator-text {
  transform: rotate(-45deg);
}

/* 区域达成时的指示样式 */
.region-indicator-success {
  border-style: solid;
  border-width: 2px;
  background: var(--indicator-color);
  color: #0f0d0d;
  box-shadow: 0 12px 22px rgba(32, 45, 66, 0.24);
}

.region-indicator-success .indicator-text {
  color: #ffffff;
}

.area-rule-legend {
  margin-top: 0.75rem;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  column-gap: 1.2rem;
  row-gap: 1.1rem;
  max-width: 680px;
  width: 100%;
  justify-items: start;
}

.legend-item {
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
  padding: 0.25rem 0.35rem;
}

.legend-diamond {
  --diamond-color: #d05263;
  --diamond-fill: #f5d5d7;
  width: 32px;
  height: 32px;
  aspect-ratio: 1 / 1;
  flex-shrink: 0;
  transform: rotate(45deg);
  border-radius: 8px;
  border: 2px solid var(--diamond-color);
  background: var(--diamond-fill);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 15px;
  font-weight: 700;
  color: var(--diamond-color);
  box-shadow: 0 4px 10px rgba(32, 45, 66, 0.15);
}

.legend-diamond .legend-symbol {
  transform: rotate(-45deg);
  display: inline-block;
}

.legend-diamond--sum {
  --diamond-color: #408fb0;
  --diamond-fill: #ffffff;
}

.legend-diamond--greater {
  --diamond-color: #6b5dd1;
  --diamond-fill: #ffffff;
}

.legend-diamond--less {
  --diamond-color: #b34c9c;
  --diamond-fill: #ffffff;
}

.legend-diamond--equal {
  --diamond-color: #d05263;
  --diamond-fill: hsl(0, 0%, 100%);
}

.legend-diamond--different {
  --diamond-color: #5fa673;
  --diamond-fill: #ffffff;
}

.legend-diamond--filled {
  --diamond-color: #5fa673;
  --diamond-fill: #5fa673;
  color: #ffffff;
  box-shadow: 0 6px 14px rgba(37, 99, 79, 0.25);
}

.legend-diamond--filled .legend-symbol {
  color: #ffffff;
}

.legend-description {
  display: inline-block;
  line-height: 1.6;
  color: var(--text-secondary);
}

/* 免责声明栏样式 */
.disclaimer-bar {
  background: linear-gradient(135deg, #f4eccc 0%, #f7e7a9 100%);
  border: 1px solid #ca8a1b;
  border-radius: 12px;
  margin: 16px auto;
  padding: 12px 16px;
  box-shadow: 0 2px 8px rgba(245, 158, 11, 0.15);
  max-width: 700px;
  width: 100%;
}

.disclaimer-content {
  display: flex;
  align-items: flex-start;
  gap: 8px;
  max-width: 100%;
}

.disclaimer-icon {
  font-size: 16px;
  flex-shrink: 0;
  margin-top: 1px;
}

.disclaimer-text {
  font-size: 0.85rem;
  line-height: 1.4;
  color: #92400e;
  font-weight: 500;
  flex: 1;
}

/* 响应式设计 */
@media (max-width: 768px) {
  .disclaimer-bar {
    margin: 12px 0;
    padding: 10px 12px;
  }
  
  .disclaimer-text {
    font-size: 0.8rem;
  }
}

/* 托盘面板样式 */
.tray-container {
  background: rgba(255, 255, 255, 0.96);
  border-radius: 24px;
  padding: 26px;
  box-shadow: var(--shadow-soft);
  border: 1px solid rgba(109, 120, 143, 0.16);
  width: min(100%, 700px);
  display: flex;
  flex-direction: column;
  align-items: center;
}

.tray-stack {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 18px;
  width: 100%;
}

.tray-hint {
  font-size: 0.95rem;
  color: var(--text-secondary);
  text-align: center;
  margin: 20px 0 0;
}

.theme-toggle-row {
  display: flex;
  justify-content: center;
  width: 100%;
}

.theme-toggle-block {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
}

.theme-toggle-hint {
  margin: 0;
  font-size: 0.85rem;
  color: var(--text-secondary);
  text-align: center;
}

.theme-toggle-bar {
  display: inline-flex;
  align-items: center;
  padding: 3px;
  gap: 4px;
  border-radius: 14px;
  border: 1px solid rgba(109, 120, 143, 0.28);
  background: rgba(255, 255, 255, 0.92);
  box-shadow: none;
}

.theme-toggle-segment {
  width: 52px;
  height: 44px;
  border-radius: 12px;
  border: none;
  background: transparent;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: background-color 0.2s ease, box-shadow 0.2s ease, transform 0.16s ease;
}

.theme-toggle-segment:hover {
  background: rgba(60, 111, 245, 0.12);
}

body.dark-mode .theme-toggle-segment:hover {
  background: rgba(96, 165, 250, 0.16);
}

.theme-toggle-segment:active {
  transform: translateY(0);
}

.theme-toggle-segment:focus-visible {
  outline: 3px solid rgba(60, 111, 245, 0.32);
  outline-offset: 3px;
}

.theme-toggle-segment.is-active {
  box-shadow: 0 0 0 1px rgba(96, 165, 250, 0.28) inset;
}

.theme-toggle-segment-icon {
  width: 24px;
  height: 24px;
  object-fit: contain;
  filter: none;
  opacity: 0.9;
}

/* Make left/right meanings obvious */
.theme-toggle-segment[data-theme="light"].is-active {
  background: linear-gradient(180deg, rgba(253, 230, 138, 0.95), rgba(251, 191, 36, 0.9));
  box-shadow: 0 0 0 1px rgba(251, 191, 36, 0.45) inset, 0 10px 18px rgba(120, 90, 20, 0.12);
}

.theme-toggle-segment[data-theme="dark"].is-active {
  background: linear-gradient(180deg, rgba(59, 130, 246, 0.95), rgba(29, 78, 216, 0.92));
  box-shadow: 0 0 0 1px rgba(96, 165, 250, 0.42) inset, 0 12px 20px rgba(29, 78, 216, 0.18);
}

.theme-toggle-segment.is-active .theme-toggle-segment-icon {
  opacity: 1;
}

/* Avoid extra inline box from <picture> */
.theme-toggle-segment picture {
  display: contents;
}

/* Icon contrast rules (PNG can't be recolored directly) */
.theme-toggle-segment[data-theme="dark"].is-active .theme-toggle-segment-icon {
  filter: invert(1);
}

body.dark-mode .theme-toggle-segment-icon {
  filter: invert(1);
  opacity: 0.92;
}

body.dark-mode .theme-toggle-segment[data-theme="light"].is-active .theme-toggle-segment-icon {
  filter: none;
}

/* 托盘标题 */
.tray-container h2 {
  margin: 0 0 16px;
  font-size: 1.1rem;
  color: var(--text-primary);
  letter-spacing: -0.01em;
}

/* 托盘内骨牌的弹性布局 */
.tray {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  align-content: flex-start;
  gap: 5px;
}

.puzzles-loading .tray {
  min-height: calc(var(--tile-size) * 3.6 + 40px);
}

/* 托盘骨牌的外层容器 */
.domino {
  position: relative;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  cursor: grab;
  user-select: none;
  transition: none;
  background: transparent;
  border: none;
  padding: 0;
  box-shadow: none;
  overflow: visible;
  z-index: 1;
}

.domino.domino-drag-preview {
  position: absolute;
  top: -9999px;
  left: -9999px;
  pointer-events: none;
  cursor: grabbing;
  opacity: 0.95;
  z-index: 9999;
}

.domino.domino-drag-preview .domino-content {
  box-shadow: 0 18px 32px rgba(15, 23, 42, 0.24);
}

/* 可旋转的骨牌内部结构 */
.domino-content {
  display: inline-flex;
  gap: 4px;
  padding: 0px;
  border-radius: 12px;
  background: rgba(255, 255, 255, 0.96);
  border: 4px solid rgba(0, 0, 0, 0.24);
  box-shadow: 0 8px 16px rgba(32, 45, 66, 0.12);
  transform-origin: center;
  transition: none;
}

/* 骨牌的旋转状态 */
.domino[data-rot='0'] .domino-content { transform: rotate(0deg); }
.domino[data-rot='1'] .domino-content { transform: rotate(90deg); }
.domino[data-rot='2'] .domino-content { transform: rotate(180deg); }
.domino[data-rot='3'] .domino-content { transform: rotate(270deg); }

/* 骨牌悬停轻微抬升 - 禁用动画 */
.domino:hover {
  transform: none;
}

.domino:hover .domino-content {
  box-shadow: 0 8px 16px rgba(32, 45, 66, 0.12);
}

/* 骨牌按下反馈 - 禁用动画 */
.domino:active {
  cursor: grabbing;
  transform: none;
}

.domino:active .domino-content {
  box-shadow: 0 8px 16px rgba(15, 23, 42, 0.12);
}

/* 骨牌键盘聚焦样式 */
.domino:focus-visible {
  outline: 3px solid rgba(37, 99, 235, 0.35);
  outline-offset: 3px;
}

/* 悬停或激活时提高骨牌层级 */
.domino:hover,
.domino:active,
.domino:focus-visible {
  z-index: 6;
}

/* 骨牌内的单个骰子格 */
.tile {
  width: var(--tile-size);
  height: var(--tile-size);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 29px;
  font-weight: 700;
  color: var(--text-primary);
  background: var(--surface-soft);
  border-radius: 8px;
  border: 0.2px solid rgba(255, 255, 255, 0.28);
  box-shadow: inset 0 1px 4px rgba(15, 23, 42, 0.08);
  flex: none;
  position: relative;
  overflow: hidden;
}

/* 骰子面九宫格容器 */
.die-face {
  position: relative;
  width: 100%;
  height: 100%;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  grid-template-rows: repeat(3, 1fr);
  gap: calc(var(--tile-size) * 0.1);
  padding: calc(var(--tile-size) * 0.15);
}

/* 棋盘中的骰子不需要padding，因为cell已经提供了居中 */
.die-face.board-die {
  width: var(--tile-size);
  height: var(--tile-size);
  padding: calc(var(--tile-size) * 0.1);
}

/* 单个骰子点数 */
.die-face .pip {
  width: calc(var(--tile-size) * 0.16);
  height: calc(var(--tile-size) * 0.16);
  border-radius: 50%;
  background: rgba(17, 24, 39, 0.9);
  margin: auto;
  opacity: 0;
  transition: opacity 0.15s ease;
}

/* 禁用过渡动画的类，用于避免清除时的闪现 */
.die-face.no-transition .pip {
  transition: none;
}

/* 骰子点在九宫格中的位置 */
.pip-top-left { grid-area: 1 / 1; }
.pip-top-right { grid-area: 1 / 3; }
.pip-top-center { grid-area: 1 / 2; }
.pip-middle-left { grid-area: 2 / 1; }
.pip-center { grid-area: 2 / 2; }
.pip-middle-right { grid-area: 2 / 3; }
.pip-bottom-left { grid-area: 3 / 1; }
.pip-bottom-center { grid-area: 3 / 2; }
.pip-bottom-right { grid-area: 3 / 3; }

/* 不同点数对应的显示规则 */
.die-value-0 .pip { opacity: 0; }
.die-value-1 .pip-center,
.die-value-3 .pip-center,
.die-value-5 .pip-center { opacity: 1; }
.die-value-2 .pip-top-left,
.die-value-2 .pip-bottom-right,
.die-value-3 .pip-top-left,
.die-value-3 .pip-bottom-right,
.die-value-4 .pip-top-left,
.die-value-4 .pip-top-right,
.die-value-4 .pip-bottom-left,
.die-value-4 .pip-bottom-right,
.die-value-5 .pip-top-left,
.die-value-5 .pip-top-right,
.die-value-5 .pip-bottom-left,
.die-value-5 .pip-bottom-right,
.die-value-6 .pip-top-left,
.die-value-6 .pip-top-right,
.die-value-6 .pip-middle-left,
.die-value-6 .pip-middle-right,
.die-value-6 .pip-bottom-left,
.die-value-6 .pip-bottom-right { opacity: 1; }
.die-value-6 .pip-center { opacity: 0; }
.die-value-empty .pip { opacity: 0; }

/* 提示条样式 */
.message {
  min-height: 46px;
  font-size: 0.95rem;
  color: var(--text-primary);
  background: rgba(255, 255, 255, 0.95);
  border-left: 4px solid rgba(60, 111, 245, 0.42);
  border-radius: 18px;
  padding: 16px 20px;
  box-shadow: 0 16px 26px rgba(32, 45, 66, 0.14);
  max-width: 660px;
}

/* 生成谜题时的特殊样式 */
.generating-message {
  background: rgba(34, 197, 94, 0.12);
  border-left-color: #22c55e;
}

/* 玩法说明卡片样式 */
.rules {
  margin: 0;
  background: rgba(255, 255, 255, 0.95);
  border-radius: 24px;
  padding: 28px 32px;
  box-shadow: var(--shadow-soft);
  border: 1px solid rgba(109, 120, 143, 0.16);
  width: min(100%, 700px);
}

.rules-puzzle-figure {
  margin: 18px auto 22px;
  max-width: 520px;
}

.rules-puzzle-figure img {
  display: block;
  width: 100%;
  height: auto;
  border-radius: 18px;
  box-shadow: 0 18px 28px rgba(23, 29, 41, 0.12);
}

/* FAQ部分样式 */
.faq {
  margin: 24px 0 0;
  background: rgba(255, 255, 255, 0.95);
  border-radius: 24px;
  padding: 28px 32px;
  box-shadow: var(--shadow-soft);
  border: 1px solid rgba(109, 120, 143, 0.16);
  width: min(100%, 700px);
}

.faq h2 {
  margin: 0 0 20px;
  font-size: 1.25rem;
  color: var(--text-primary);
}

.faq-content h3 {
  margin: 20px 0 8px;
  font-size: 1rem;
  color: var(--text-primary);
  font-weight: 600;
}

.faq-content h3:first-child {
  margin-top: 0;
}

.faq-content p {
  margin: 0 0 16px;
  line-height: 1.6;
  color: var(--text-secondary);
}

/* 玩法标题 */
.rules h2 {
  margin: 0 0 1px;
  font-size: 1.25rem;
  color: var(--text-primary);
}

/* 玩法列表 */
.rules ul {
  margin: 0;
  padding-left: 22px;
  line-height: 1.65;
  color: var(--text-secondary);
}

.rules kbd {
  display: inline-block;
  padding: 2px 6px;
  border-radius: 6px;
  background: rgba(44, 51, 66, 0.08);
  font-size: 0.86em;
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
}

.rule-highlight {
  color: var(--accent-strong);
  font-weight: 700;
}

/* 通用模态框遮罩 */
.modal-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(15, 23, 42, 0.6);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 50;
  padding: 24px;
}

/* 模态框面板样式 */
.modal {
  background: #ffffff;
  border-radius: 24px;
  box-shadow: var(--shadow-medium);
  max-width: 520px;
  width: 100%;
  padding: 32px;
  position: relative;
}

/* 模态框标题 */
.modal h2 {
  margin: 0 0 16px;
  color: var(--text-primary);
}

/* 模态框段落间距 */
.modal p {
  margin: 0 0 12px;
  color: var(--text-secondary);
}

/* 模态框内按钮行 */
.modal-actions {
  display: flex;
  justify-content: flex-end;
  gap: 12px;
  margin-top: 24px;
}

/* 模态框关闭按钮 */
.close-button {
  position: absolute;
  top: 14px;
  right: 14px;
  border: none;
  background: transparent;
  color: var(--text-secondary);
  font-size: 1.2rem;
  cursor: pointer;
}

/* 反馈表单布局 */
.feedback-form {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

/* 表单标签样式 */
.feedback-form label {
  font-weight: 600;
  color: var(--text-primary);
}

/* 表单输入字段 */
.feedback-form input,
.feedback-form textarea {
  width: 100%;
  padding: 10px 12px;
  border: 1px solid rgba(148, 163, 184, 0.55);
  border-radius: 12px;
  font-family: inherit;
  font-size: 0.95rem;
  color: var(--text-primary);
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
  background: rgba(248, 250, 255, 0.72);
}

/* 输入框聚焦描边 */
.feedback-form input:focus,
.feedback-form textarea:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.18);
  outline: none;
}

/* 较大的文本域 */
.feedback-form textarea {
  min-height: 130px;
  resize: vertical;
}

/* 胜利模态内的分享按钮容器 */
.share-buttons {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 16px;
}

/* 分享按钮样式 */
.share-buttons a,
.share-buttons button.copy-share {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 18px;
  border-radius: 999px;
  border: 1px solid rgba(109, 120, 143, 0.24);
  background: rgba(255, 255, 255, 0.96);
  color: var(--text-secondary);
  text-decoration: none;
  font-weight: 600;
  font-size: 0.9rem;
  cursor: pointer;
  transition: background 0.2s ease, color 0.2s ease, box-shadow 0.2s ease;
}

/* 分享按钮悬停效果 */
.share-buttons a:hover,
.share-buttons button.copy-share:hover {
  background: rgba(60, 111, 245, 0.14);
  color: var(--accent-strong);
  box-shadow: 0 10px 18px rgba(32, 45, 66, 0.12);
}

/* 页眉中的内联分享栏 */
.share-inline {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  align-items: center;
  justify-content: center;
}

/* 内联分享按钮样式 */
.share-inline a {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 18px;
  border-radius: 999px;
  border: 1px solid rgba(109, 120, 143, 0.24);
  background: rgba(255, 255, 255, 0.96);
  color: var(--text-secondary);
  text-decoration: none;
  font-weight: 600;
  font-size: 0.9rem;
  cursor: pointer;
  transition: background 0.2s ease, color 0.2s ease, box-shadow 0.2s ease;
  vertical-align: middle;
}

/* 内联分享按钮悬停 */
.share-inline a:hover {
  background: rgba(60, 111, 245, 0.14);
  color: var(--accent-strong);
  box-shadow: 0 10px 18px rgba(32, 45, 66, 0.12);
}

/* 复制分享按钮强调样式 */
.copy-share {
  background: #8b5cf6;
  color: #ffffff;
  border-color: #8b5cf6;
  font-size: 0.9rem;
}

/* 页眉copy link按键特殊样式 - 确保与其他分享按键一致 */
.share-inline a.copy-share {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 18px;
  border-radius: 999px;
  border: 1px solid #374151;
  background: #374151;
  color: #ffffff;
  text-decoration: none;
  font-weight: 600;
  font-size: 0.9rem;
  cursor: pointer;
  transition: background 0.2s ease, color 0.2s ease, box-shadow 0.2s ease;
  vertical-align: middle;
}

/* 页眉copy link按键悬停效果 */
.share-inline a.copy-share:hover {
  background: #7c3aed;
  color: #ffffff;
  box-shadow: 0 12px 20px rgba(139, 92, 246, 0.28);
}

.share-icon {
  font-size: 1rem;
  line-height: 1;
}

.share-icon svg {
  width: 1em;
  height: 1em;
  display: block;
}

.share-label {
  display: inline-block;
  vertical-align: middle;
  line-height: 1;
}

.share-inline a[data-share-target="twitter"],
.share-buttons a[data-share-target="twitter"] {
  background: #000000;
  color: #ffffff;
  border-color: #000000;
}

.share-inline a[data-share-target="twitter"]:hover,
.share-buttons a[data-share-target="twitter"]:hover {
  background: #333333;
  box-shadow: 0 12px 20px rgba(0, 0, 0, 0.28);
}

.share-inline a[data-share-target="reddit"],
.share-buttons a[data-share-target="reddit"] {
  background: #ff4500;
  color: #ffffff;
  border-color: #ff4500;
}

.share-inline a[data-share-target="reddit"]:hover,
.share-buttons a[data-share-target="reddit"]:hover {
  background: #cc3700;
  box-shadow: 0 12px 20px rgba(255, 69, 0, 0.32);
}

.share-inline a[data-share-target="facebook"],
.share-buttons a[data-share-target="facebook"] {
  background: #1877f2;
  color: #ffffff;
  border-color: #1877f2;
}

.share-inline a[data-share-target="facebook"]:hover,
.share-buttons a[data-share-target="facebook"]:hover {
  background: #0f5ad6;
  box-shadow: 0 12px 20px rgba(24, 119, 242, 0.28);
}

.share-inline a[data-share-target="email"],
.share-buttons a[data-share-target="email"] {
  background: #10b981;
  color: #ffffff;
  border-color: #10b981;
}

.share-inline a[data-share-target="email"]:hover,
.share-buttons a[data-share-target="email"]:hover {
  background: #059669;
  box-shadow: 0 12px 20px rgba(16, 185, 129, 0.28);
}

.site-footer {
  margin: 72px auto 24px;
  padding: 32px 24px;
  max-width: 1180px;
  display: flex;
  flex-direction: column;
  gap: 18px;
  align-items: center;
  text-align: center;
  color: var(--text-secondary);
}

.footer-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  justify-content: center;
  font-size: 0.92rem;
}

.footer-links {
  display: inline-flex;
  gap: 16px;
  flex-wrap: wrap;
  justify-content: center;
  font-size: 0.86rem;
}

.footer-links a,
.footer-feedback {
  color: var(--accent-strong) !important;
  font-weight: 700;
  text-decoration: none;
  padding: 6px 10px;
  border-radius: 999px;
  background: rgba(60, 111, 245, 0.1);
  transition: background 0.2s ease, color 0.2s ease;
  border: none;
  cursor: pointer;
  font-family: inherit;
  font-size: inherit;
  line-height: inherit;
  margin: 0;
  outline: none;
  display: inline-block;
}

.footer-links a:hover,
.footer-feedback:hover {
  background: rgba(60, 111, 245, 0.16);
  color: var(--accent) !important;
}

.footer-note {
  margin: 4px 0 0;
  font-size: 0.85rem;
  color: var(--text-secondary);
  line-height: 1.5;
  text-align: center;
  max-width: 680px;
}

.policy-page {
  max-width: 860px;
  margin: 0 auto;
  padding: 72px 24px 120px;
  color: var(--text-primary);
}

.policy-header {
  text-align: center;
  margin-bottom: 42px;
}

.policy-header h1 {
  margin-bottom: 12px;
}

.policy-page section {
  margin-bottom: 32px;
  background: rgba(255, 255, 255, 0.78);
  border-radius: 20px;
  padding: 24px 28px;
  box-shadow: 0 12px 24px rgba(32, 45, 66, 0.08);
  border: 1px solid rgba(109, 120, 143, 0.12);
}

.policy-page section h2 {
  margin-top: 0;
  color: var(--accent-strong);
}

.policy-page a {
  color: var(--accent);
  font-weight: 600;
  text-decoration: none;
}

.policy-page a:hover {
  text-decoration: underline;
}

.policy-footer {
  margin-top: 48px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 12px;
  font-size: 0.92rem;
  color: var(--text-secondary);
}

.policy-footer a,
.policy-footer button {
  background: rgba(60, 111, 245, 0.12);
  padding: 6px 14px;
  border-radius: 999px;
  color: var(--accent-strong);
  font-weight: 600;
  border: none;
  cursor: pointer;
  text-decoration: none;
}

.policy-footer a:hover,
.policy-footer button:hover {
  background: rgba(60, 111, 245, 0.2);
}

/* Dark mode styles for policy pages */
body.dark-mode .policy-page {
  color: var(--text-primary);
}

body.dark-mode .policy-page section {
  background: var(--surface);
  border-color: var(--neutral-border);
  box-shadow: 0 12px 24px rgba(0, 0, 0, 0.3);
}

body.dark-mode .policy-page section h2 {
  color: var(--accent);
}

body.dark-mode .policy-page a {
  color: var(--accent);
}

body.dark-mode .policy-page a:hover {
  color: var(--accent-strong);
}

body.dark-mode .policy-footer {
  color: var(--text-secondary);
}

body.dark-mode .policy-footer a,
body.dark-mode .policy-footer button {
  background: var(--accent-soft);
  color: var(--accent);
}

body.dark-mode .policy-footer a:hover,
body.dark-mode .policy-footer button:hover {
  background: rgba(96, 165, 250, 0.25);
  color: var(--accent-strong);
}

body.dark-mode .policy-header h1 {
  color: var(--text-primary);
}

body.dark-mode .policy-header p {
  color: var(--text-secondary);
}

body.dark-mode .policy-page code {
  background: var(--surface-soft);
  color: var(--text-primary);
  border: 1px solid var(--neutral-border);
}

.toast {
  position: fixed;
  left: 50%;
  bottom: 32px;
  transform: translateX(-50%) translateY(20px);
  background: rgba(35, 45, 65, 0.92);
  color: #fff;
  padding: 12px 20px;
  border-radius: 999px;
  font-size: 0.95rem;
  font-weight: 600;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.25s ease, transform 0.25s ease;
  z-index: 200;
}

.toast-visible {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

/* 隐藏元素的工具类 */
.hidden {
  display: none !important;
}

/* 模态框打开时禁止页面滚动 */
body.modal-open {
  overflow: hidden;
}

@media (max-width: 960px) {
  :root {
    --tile-size: 56px;
    --board-padding: 14px;
  }
  .board-container {
    align-self: center;
  }
  .utility-bar {
    gap: 12px;
  }
  .controls {
    gap: 10px;
  }
  .control-toolbar {
    gap: 8px;
  }
}

/* iPad端优化 - 当页面变窄时使用图标代替文字 */
@media (max-width: 900px) and (min-width: 721px) {
  .toolbar-text {
    display: none;
  }
  
  .toolbar-btn {
    min-width: 48px;
    padding: 8px 6px;
    justify-content: center;
  }
  
  .controls {
    gap: 8px;
  }
  
  .control-toolbar {
    gap: 6px;
  }
}

/* iPad分屏模式优化 - 更紧凑的布局 */
@media (max-width: 850px) and (min-width: 721px) {
  .utility-bar {
    gap: 8px;
  }
  
  .utility-left {
    gap: 8px;
  }
  
  .puzzle-meta {
    font-size: 0.9rem;
  }
  
  .timer {
    font-size: 0.9rem;
  }
  
  .controls {
    gap: 6px;
  }
  
  .control-toolbar {
    gap: 4px;
  }
  
  .toolbar-btn {
    min-width: 44px;
    padding: 6px 4px;
    justify-content: center;
  }
  
  .difficulty-chip {
    gap: 4px;
  }
  
  .difficulty-chip-option {
    padding: 4px 8px;
    font-size: 0.85rem;
  }
}

@media (max-width: 600px) {
  :root {
    --tile-size: 48px;
  }
  .tile {
    font-size: 20px;
  }
  .puzzle-meta {
    padding: 6px 12px;
  }
  
  .toolbar-btn {
    min-width: 40px;
    padding: 6px 2px;
  }
}
@media (max-width: 720px) {
  .utility-bar {
    flex-direction: column;
    align-items: stretch;
    gap: 12px;
  }

  .utility-left {
    width: 100%;
    justify-content: space-between;
    gap: 10px;
    margin-right: 0;
  }

  .controls {
    width: 100%;
    flex-direction: column;
    align-items: stretch;
    gap: 12px;
    overflow-x: visible;
  }

  .control-toolbar {
    width: 100%;
    flex-wrap: nowrap;
    justify-content: space-between;
    gap: 8px;
    overflow-x: visible;
    padding-bottom: 0;
  }

  .toolbar-btn {
    flex: 1 1 auto;
    min-width: 48px;
    justify-content: center;
    padding: 8px 4px;
  }

  .toolbar-text {
    display: none;
  }

  .difficulty-chip {
    width: 100%;
    gap: 6px;
    justify-content: space-between;
  }

  .difficulty-chip-option {
    flex: 1 1 auto;
    padding: 6px 0;
    text-align: center;
  }
}