feat(post): fix design html

src/app/post/components/post-card/post-card.component.scss

.../post/components/post-details/post-details.component.html

.../post/components/post-details/post-details.component.scss

...pp/post/components/post-details/post-details.component.ts

...pp/post/components/post-header/post-header.component.scss

src/app/post/components/post-list/post-list.component.ts

src/app/post/models/post.model.ts

src/app/post/services/post.service.ts

src/assets/scss/_layout.scss

src/assets/scss/_typography.scss