Getter and setter method in Lightning web component & CSS Behaviour In Lightning Web component 

Learn How to Use Getters and Setters in Salesforce Lightning
Use of Getter & Setter
Understanding Setters and Getters in Lightning
Getter and Setter in apex class
LWC Setters and Getters in Detail
Getter Property in Lighting
Learn Salesforce Development
CSS For LWC Lightning Web Component- In Salesforce
LWC | CSS Style Sheet | How to Apply CSS in Lightning Web Component
Salesforce Lightning
Lightning Web Components