Stricter checks to prevent #156

* fixes #156
* log content hidden via CSS bigger than 1 kB

```
22:42:15.811 Hidden content: body > div.wrapper > div.site.clearfix > div#site-container > div.container > div.columns.profilecols.js-username > div.column-main > div.tab-content.js-repo-filter > div.contributions-tab > div#contribution-activity > div.period-filter.clearfix > div.select-menu.js-menu-container.js-select-menu.js-period-container > div.select-menu-modal-holder.js-menu-content.js-navigation-container (1817 bytes)
```