[建议]尽可能的利用css去计算？

• 1.用hidden=!0 替代 style.display=none更有性价比。

• 2.编辑区和预览区放在一个容器里面，方面当竖屏可以竖排而不是只能横排溢出

• 3.很明显给主容器加height:100%没什么用,不如增加几层DIV,flex垂直布局,让编辑预览区自动适应高度,这样无需要JS去设置min-height

CSS变量化建议

一些浮动定位数据用var(--cherry-toolbar-xxx)
添加一个唯一的随机id标记主容器，类似这样

function creatSheet(){
  var style = document.querySelector('#cherry-css-var');
  if(!style)){
    style = document.head.appendChild(document.createElement('style'));
    style.setAttribute('id','cherry-css-var');
  }
  return style.sheet;
}
var css_var = {};
var css_pos;
var css_id = '#cherry-'+Math.random().toString().slice(2);
function updateVar(obj,prefix){
  let sheet = creatSheet();
  prefix = prefix?'-'+prefix+'-':'-';
  Object.entries(obj).forEach(entry=>{
    css_var['--cherry'+prefix+entry[0]] = entry[1]?entry[1]:'';
  });
  Object.assign(css_var,obj);
  if(css_pos===undefined){
    css_pos = sheet.rules.length;
  }
  if(sheet.rules[css_pos])sheet.deleteRule(css_pos);
  sheet.insertRule(css_id+'{'+ Object.entries(css_var).map(v=>v[0]+':'+v[1]).join(';')+'}',css_pos);
}

updateVar({top:'0px'},'toolbar');

这些理论上dom几乎无修改，而且css calc min max运算有时候比js好用，特别自适应方面。

Start by reviewing the editor and preview container layout, toolbar positioning, and the JavaScript style and min-height updates described in the issue. Done should include the proposed CSS-based sizing and responsive vertical layout, with the dynamic style changes and CSS variables working without unnecessary DOM updates.