Hello,
You have 2 point to check :
1°) Try to switch to a default template like ProtoStar, if that solve your issue or part of your issue, that means that your template add css command that leads to this result, and so in this case we invite you to contact your Template creator support.
2°) You can try to switch your frontend custom css for the default one, see the screenshot :
If that solve again part or completely your issue that means that you have
some custom css command maybe to remove or correct.
Regards