fix css and add responsive css

src/components/profile/UpdateProfileForm.jsx

src/components/thread/CreateThread.jsx

src/components/thread/EditThread.jsx

src/components/thread/Post.jsx

src/components/thread/Thread.jsx

src/components/topic/CreateTopicForm.jsx

src/components/topic/TopicList.jsx

src/components/utility/Footer.jsx

src/components/utility/Navbar.jsx

src/styles/App.css

src/styles/LoginForm.css

src/styles/Search.css

src/styles/profile/Profile.css

src/styles/profile/UpdateProfileForm.css

src/styles/thread/EditThread.css

src/styles/thread/Form.css

src/styles/thread/ListThreads.css

src/styles/thread/Post.css

src/styles/thread/PreviewThread.css

src/styles/thread/Thread.css