{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# 查询选择器\n",
    "\n",
    "要操作像文档 `body` 这样的元素，您可以使用 `ui.query` 函数。通过查询结果，您可以像操作其他 UI 元素一样添加类、样式和属性。例如，这可以用于更改页面背景颜色（例如 `ui.query('body').classes('bg-green')`）。\n",
    "\n",
    "`selector`：CSS 选择器（例如 `\"body\"`、`\"#my-id\"`、`\".my-class\"`、`\"div > p\"`）"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "<nicegui.elements.button.Button at 0x1e7868e41d0>"
      ]
     },
     "execution_count": 1,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "from nicegui import ui\n",
    "\n",
    "def set_background(color: str) -> None:\n",
    "    ui.query('body').style(f'background-color: {color}')\n",
    "\n",
    "ui.button('Blue', on_click=lambda: set_background('#ddeeff'))\n",
    "ui.button('Orange', on_click=lambda: set_background('#ffeedd'))\n",
    "\n",
    "# ui.run()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## 设置背景渐变\n",
    "\n",
    "设置背景渐变、图像或类似效果非常简单。有关使用 CSS 设置背景的更多信息，请参见 [`w3schools.com`](https://www.w3schools.com/cssref/pr_background-image.php)。"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "<nicegui.elements.query.Query at 0x1e785cd73d0>"
      ]
     },
     "execution_count": 2,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "from nicegui import ui\n",
    "\n",
    "ui.query('body').classes('bg-gradient-to-t from-blue-400 to-blue-100')\n",
    "\n",
    "# ui.run()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## 修改默认页面内边距\n",
    "\n",
    "默认情况下，NiceGUI 在页面内容周围提供了一个内置的内边距。您可以使用类选择器 `.nicegui-content` 来修改它。"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [],
   "source": [
    "from nicegui import ui\n",
    "\n",
    "ui.query('.nicegui-content').classes('p-0')\n",
    "with ui.column().classes('h-screen w-full bg-gray-400 justify-between'):\n",
    "    ui.label('top left')\n",
    "    ui.label('bottom right').classes('self-end')\n",
    "\n",
    "# ui.run()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  }
 ],
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