/* 问号图标 */
.help-icon {
  display: inline-block;
  margin-left: 8px;
  color: #888;
  font-weight: bold;
  cursor: help;
}
.help-icon:hover { color: #4CAF50; }

/* Portal Tooltip（挂在 body 下） */
.tooltip-portal {
  position: fixed;   /* 不受父级 overflow 影响 */
  left: 0; top: 0;
  z-index: 999999;   /* 足够高，覆盖侧栏等 */
  display: none;
  opacity: 0;
  transition: opacity .08s linear;

  background: rgba(0,0,0,.9);
  color: #fff;
  padding: 6px 10px;
  border-radius: 6px;
  font-size: 13px;
  line-height: 1.4;
  pointer-events: none; /* 鼠标穿透，避免闪烁 */
  white-space: nowrap;
  box-shadow: 0 4px 12px rgba(0,0,0,.25);
}



.add-step-btn, .add-phase-btn {
  background-color: #4CAF50;
  color: white;
  display: block; 
  border: none;
  padding: 5px 10px;
  font-size: 14px;
  border-radius: 5px;
  cursor: pointer;
  margin-top: 5px;
  margin-left: 10px;
}
.add-step-btn{
  margin-left: 30px;
}
.add-step-btn:hover, .add-phase-btn:hover {
  background-color: #45a049;
}

/* 增加按钮与大纲列表的间距 */
#outline-tree li {
  margin: 5px 0;
}

#outline-tree li.lvl2 {
  padding-left: 1px;
}

#outline-tree li.lvl3 {
  padding-left: 20px;
}




/* 删除模式下可删除的节点样式 */
  .outline.delete-mode #outline-tree .lvl2,
  .outline.delete-mode #outline-tree .lvl3 {
    border: 1px solid #dc2626;         /* 红色边框 */
    border-radius: 6px;
    padding: 4px 6px;
    transition: background-color .15s ease, box-shadow .15s ease;
    cursor: pointer;
  }
  .outline.delete-mode #outline-tree .lvl2:hover,
  .outline.delete-mode #outline-tree .lvl3:hover {
    background: rgba(220,38,38,.06);   /* 微红背景 */
    box-shadow: 0 0 0 2px rgba(220,38,38,.15) inset;
  }

  /* 删除按钮样式（可按需调整） */
  .delete-btn {
    margin-left: 6px;
    border: none;
    background: transparent;
    cursor: pointer;
    padding: 6px;
    border-radius: 8px;
  }
  .delete-btn[aria-pressed="true"] {
    background: rgba(220,38,38,.12);
    outline: 2px solid #dc2626;
  }
  .delete-btn:focus-visible { outline: 2px solid #4c9ffe; }





  .details-header { display:flex; justify-content:space-between; align-items:center; }
  .close-btn { border:none; background:transparent; font-size:22px; cursor:pointer; }
  
  /* 主体布局 */
  .lesson-editor { display:flex; height: calc(100vh - 20px); gap: 12px; padding: 12px; }
  .outline {
    width: 280px; border:1px solid #eee; border-radius:10px; padding:10px;
    overflow:auto; background:#fafafa;
  }
  .outline-header { font-weight:700; margin-bottom:8px; }
  #outline-tree { list-style:none; padding-left:0; }
  #outline-tree li { margin:4px 0; cursor:pointer; }
  #outline-tree .lvl1 { font-weight:700; }
  #outline-tree .lvl2 { margin-left:12px; }
  #outline-tree .lvl3 { margin-left:24px; }
  #outline-tree li.active { background:#eaf6ff; border-radius:6px; font-weight: bold; }
  
  .editor-pane {
    flex:1; display:flex; flex-direction:column; min-width:0;
    border:1px solid #eee; border-radius:10px;
  }
  .editor-tabs { display:flex; align-items:center; gap:8px; padding:8px; border-bottom:1px solid #eee; }
  .tab-btn { border:1px solid #ddd; background:#fff; padding:6px 10px; border-radius:8px; cursor:pointer; }
  .tab-btn.active { background:#f0f8ff; border-color:#a0c4ff; }
  .actions { margin-left:auto; }
  .actions button { padding:6px 12px; border:none; border-radius:8px; background:#4CAF50; color:#fff; cursor:pointer; }
  .tab-content { flex:1; padding:8px;display: flex; }
  .tab { display:none; height:100%; }
  .tab.active { display:block; height:100%; }
  textarea {
    width:100%; height: calc(100vh - 180px);
    border:1px solid #ddd; border-radius:8px; padding:10px; font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
    box-sizing:border-box; resize: vertical;
  }