/* ============================================================
   apps/puzzle.html 样式（P0-4-T17 <style> 块外联）
   - 页面 style="..." 与 on* 仍在本页（P0-4-T18 整改）
   ============================================================ */

/* Design Token：项目级 Glassmorphism 规范（与 topbar.8d4aa38f.css 一致） */
:root {
  --glass-bg-light:           rgba(255, 255, 255, 0.55);
  --glass-border-light:        rgba(15, 23, 42, 0.06);
  --glass-highlight-light:     rgba(255, 255, 255, 0.6);
  --glass-shadow-light:        rgba(15, 23, 42, 0.06);
  --glass-bg-dark:             rgba(10, 14, 39, 0.72);
  --glass-border-dark:         rgba(255, 255, 255, 0.06);
  --glass-highlight-dark:      rgba(255, 255, 255, 0.08);
  --glass-shadow-dark:         rgba(0, 0, 0, 0.32);
  --glass-blur:                blur(20px) saturate(180%);
}

  *, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
  html, body { height: 100%; }
  :root {
    --bg-page: #fafbfc; --bg-card: #ffffff; --bg-soft: #eff6ff; --bg-header: #ffffff;
    --text-primary: #1f2937; --text-secondary: #4b5563; --text-muted: #6b7280; --text-hint: #9ca3af;
    --text-on-accent: #ffffff; --border: #e5e7eb; --border-soft: #f1f5f9;
    --accent: #3b82f6; --accent-hover: #2563eb; --accent-soft: #60a5fa; --accent-fade: rgba(59,130,246,0.10);
    --success: #10b981; --warning: #f59e0b; --danger: #ef4444;
  }
  body {
    background:
      radial-gradient(ellipse 80% 60% at 50% 0%, rgba(59,130,246,0.08) 0%, transparent 60%),
      radial-gradient(ellipse 50% 40% at 100% 100%, rgba(96,165,250,0.06) 0%, transparent 60%),
      var(--bg-page);
    color: var(--text-primary);
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
    -webkit-font-smoothing: antialiased;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
  }
  a { color: inherit; text-decoration: none; }
  /* 原顶栏「返回游戏」入口下移（顶栏已换共享组件） */
  .back-link { display: inline-block; margin-bottom: 14px; font-size: 11px; letter-spacing: 0.18em; text-transform: uppercase; color: var(--text-muted); }
  .back-link:hover { color: var(--accent); }

  main { flex: 1; padding: 32px 40px 60px; max-width: 1280px; width: 100%; margin: 0 auto; }
  .head { text-align: center; margin-bottom: 24px; }
  .head .eyebrow { font-size: 10px; letter-spacing: 0.4em; color: var(--text-muted); text-transform: uppercase; margin-bottom: 8px; }
  .head h1 { font-size: 28px; font-weight: 500; letter-spacing: 0.04em; color: var(--text-primary); }
  .head .sub { margin-top: 8px; font-size: 13px; color: var(--text-muted); }

  .diff-row { display: flex; justify-content: center; gap: 8px; margin-bottom: 20px; }
  .diff-btn { padding: 9px 22px; font-size: 12px; font-weight: 500; letter-spacing: 0.16em; text-transform: uppercase; color: var(--text-secondary); background: var(--bg-card); border: 1px solid var(--border); cursor: pointer; transition: all 0.18s ease; font-family: inherit; }
  .diff-btn:hover { border-color: var(--accent); color: var(--accent); }
  .diff-btn.active { background: var(--accent); color: var(--text-on-accent); border-color: var(--accent); }

  .game-area { display: grid; grid-template-columns: 1fr 300px; gap: 24px; align-items: start; }
  .left-col { display: flex; flex-direction: column; gap: 20px; }
  .ref-card { background: var(--bg-card); border: 1px solid var(--border-soft); padding: 16px; }
  .ref-head { display: flex; align-items: center; justify-content: space-between; margin-bottom: 12px; }
  .ref-head .l { font-size: 10px; letter-spacing: 0.3em; color: var(--text-muted); text-transform: uppercase; }
  .ref-toggle { font-size: 11px; color: var(--accent); cursor: pointer; padding: 4px 8px; border: 1px solid var(--border); }
  .ref-toggle:hover { background: var(--accent-fade); }
  .ref-body { display: flex; align-items: center; gap: 16px; }
  .ref-body.hidden { display: none; }
  .ref-canvas { width: 140px; height: 140px; border: 1px solid var(--border-soft); background: var(--bg-soft); }
  .ref-tip { font-size: 12px; color: var(--text-muted); line-height: 1.7; flex: 1; }

  .board-card { background: var(--bg-card); border: 1px solid var(--border-soft); padding: 16px; }
  .board-head { display: flex; align-items: center; justify-content: space-between; margin-bottom: 12px; }
  .board-head .l { font-size: 10px; letter-spacing: 0.3em; color: var(--text-muted); text-transform: uppercase; }
  .board-head .info { font-size: 11px; color: var(--text-hint); }
  .board-wrap {
    position: relative;
    width: 480px; max-width: 100%;
    aspect-ratio: 1;
    margin: 0 auto;
    background: var(--bg-soft);
    border: 1px solid var(--border-soft);
    user-select: none;
    touch-action: none;
  }
  .board-grid {
    position: absolute; inset: 0;
    display: grid;
    pointer-events: none;
  }
  .board-cell {
    border: 1px dashed var(--border);
    display: flex; align-items: center; justify-content: center;
    font-size: 11px; color: var(--text-hint);
    background: transparent;
  }
  .board-cell.filled { border-color: transparent; }
  .piece-in-cell { pointer-events: auto; }

  .right-col { display: flex; flex-direction: column; gap: 14px; }
  .stat-card { background: var(--bg-card); border: 1px solid var(--border-soft); padding: 18px 20px; }
  .stat-card .l { font-size: 10px; letter-spacing: 0.3em; color: var(--text-muted); text-transform: uppercase; margin-bottom: 6px; }
  .stat-card .v { font-size: 28px; font-weight: 400; color: var(--text-primary); font-family: 'SF Mono', 'Consolas', monospace; line-height: 1; }
  .stat-card .v small { font-size: 13px; color: var(--text-muted); margin-left: 4px; font-family: inherit; }
  .stat-card.best { background: var(--bg-soft); border-color: var(--accent-fade); }
  .stat-card.best .l { color: var(--accent); }
  .stat-card.best .v { color: var(--accent); font-size: 16px; font-weight: 500; font-family: inherit; }

  .tray { background: var(--bg-card); border: 1px solid var(--border-soft); padding: 14px; min-height: 200px; }
  .tray-head { font-size: 10px; letter-spacing: 0.3em; color: var(--text-muted); text-transform: uppercase; margin-bottom: 10px; }
  /* Bugfix: tray 内容多时可滚动，避免撑高整个右栏；
     关键:tray-grid 必须有 max-height 限制，flex-wrap 多行超出时自动出现滚动条 */
  .tray-grid { display: flex; flex-wrap: wrap; gap: 8px; min-height: 120px; max-height: 240px; overflow-y: auto; align-content: flex-start; padding-right: 4px; }
  .piece {
    background: var(--bg-soft);
    border: 2px solid var(--border-soft);
    cursor: grab;
    position: relative;
    transition: transform 0.18s ease, box-shadow 0.18s ease, border-color 0.18s ease;
    box-shadow: 0 1px 3px rgba(0,0,0,0.05);
  }
  .piece:hover { transform: scale(1.04); box-shadow: 0 4px 12px rgba(59,130,246,0.20); border-color: var(--accent); z-index: 5; }
  .piece.selected { border-color: var(--accent); box-shadow: 0 0 0 3px var(--accent-fade); }
  .piece.dragging { opacity: 0.5; cursor: grabbing; }
  .piece canvas { display: block; }
  .piece.solved { border-color: var(--success); box-shadow: 0 0 0 3px rgba(16,185,129,0.20); cursor: default; pointer-events: none; }
  .piece.solved::after { content: '✓'; position: absolute; top: 2px; right: 4px; color: var(--success); font-size: 12px; font-weight: 700; }

  .actions { display: flex; flex-direction: column; gap: 8px; }
  .btn { padding: 11px 16px; font-size: 12px; font-weight: 500; letter-spacing: 0.18em; text-transform: uppercase; background: var(--bg-card); color: var(--text-primary); border: 1px solid var(--border); cursor: pointer; transition: all 0.18s ease; font-family: inherit; }
  .btn:hover { border-color: var(--accent); color: var(--accent); }
  .btn:disabled { opacity: 0.4; cursor: not-allowed; }
  .btn.primary { background: var(--accent); color: var(--text-on-accent); border-color: var(--accent); }
  .btn.primary:hover { background: var(--accent-hover); border-color: var(--accent-hover); color: var(--text-on-accent); }

  .status-info { padding: 12px 14px; font-size: 12px; line-height: 1.7; color: var(--text-secondary); background: var(--bg-card); border: 1px solid var(--border-soft); }
  .status-info .guest { color: var(--warning); }

  .modal-mask { position: fixed; inset: 0; background: rgba(0,0,0,0.4); display: none; align-items: center; justify-content: center; z-index: 100; }
  .modal-mask.show { display: flex; }
  .modal { background: var(--bg-card); border: 1px solid var(--border); max-width: 440px; width: calc(100% - 40px); padding: 40px 32px; text-align: center; }
  .modal h2 { font-size: 22px; font-weight: 500; color: var(--success); margin-bottom: 6px; }
  .modal .sub { font-size: 13px; color: var(--text-muted); margin-bottom: 20px; }
  .modal .result { display: grid; grid-template-columns: 1fr 1fr 1fr; gap: 10px; margin-bottom: 20px; }
  .modal .result .r { padding: 12px 6px; background: var(--bg-soft); border: 1px solid var(--border-soft); }
  .modal .result .r .l { font-size: 10px; letter-spacing: 0.2em; color: var(--text-muted); text-transform: uppercase; margin-bottom: 4px; }
  .modal .result .r .v { font-size: 16px; font-weight: 500; color: var(--text-primary); }
  .modal .badge { display: inline-block; padding: 4px 12px; font-size: 11px; letter-spacing: 0.1em; background: var(--bg-soft); color: var(--accent); border: 1px solid var(--accent); margin-bottom: 16px; }
  .modal .badge.guest { color: var(--warning); border-color: var(--warning); }
  .modal .actions { display: flex; gap: 8px; flex-direction: row; }
  .modal .actions .btn { flex: 1; }

  .toast { position: fixed; top: 24px; left: 50%; transform: translateX(-50%) translateY(-20px); padding: 10px 18px; background: var(--text-primary); color: #fff; font-size: 13px; opacity: 0; transition: all 0.22s ease; pointer-events: none; z-index: 200; }
  .toast.show { opacity: 1; transform: translateX(-50%) translateY(0); }
  .toast.error { background: var(--danger); }
  .toast.success { background: var(--success); }

  @media (max-width: 900px) {
    main { padding: 24px 16px 40px; }
    .game-area { grid-template-columns: 1fr; }
    .right-col { order: 2; }
  }