bitrix-cms-basics

CMS basics

Baseline: main 23.0+ · Verified: main 26.800.0

Task	Read
Sites, site template layout, #WORK_AREA#	rules/sites-templates.md
Where CSS goes, Asset::addCss(), CSS merging	rules/styles.md
Page/directory properties, .section.php, menus, include areas, breadcrumbs, users	rules/pages.md
Pagination: PageNavigation, reverse/admin variants, bitrix:main.pagenavigation	rules/page-navigation.md
User fields: schema, values, public and admin output	rules/user-fields.md
Custom UF type, UF render component	rules/user-field-types.md
Landing / Sites24 pages	bitrix-landing
Mail events and templates	bitrix-mail
Files, uploads	bitrix-files

Invariants

• Templates, components and include files live in /local/; kernel templates are overridden by copies, never edited.
• Pagination: count with the same filter as the data query, set it before initFromUri(), never allowAllRecords(true) on large tables.
• UF schema only via CUserTypeEntity; UserFieldTable and UserTable are read-only.
• Escape everything a template prints (htmlspecialcharsbx).
• New code: Asset::addCss() / Extension::load() instead of SetAdditionalCSS(); D7 tablets (SiteTable, UserTable) for reads.