Design fixes (#555)

* Change placeholder color and design fixes for show page / sidebar

* Replace hardcoded border radiuses

* Improve border display for middle of button group

* Editor styling

* Editor font size

* Comment Bar positioning and remove scrollbar for 1px

* Add Comments section title

* Nit: match css style

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Co-authored-by: Emilien <emilien.chauvet.enpc@gmail.com>

front/src/modules/ui/components/property-box/PropertyBox.tsx

@@ -4,7 +4,7 @@ const StyledPropertyBoxContainer = styled.div`
   align-self: stretch;
   background: ${({ theme }) => theme.background.secondary};
   border: 1px solid ${({ theme }) => theme.border.color.medium};
-  border-radius: 4px;
+  border-radius: ${({ theme }) => theme.border.radius.sm};
   display: flex;
   flex-direction: column;
   gap: ${({ theme }) => theme.spacing(2)};

front/src/modules/ui/components/property-box/PropertyBoxItem.tsx

@@ -2,8 +2,10 @@ import { ReactNode } from 'react';
 import styled from '@emotion/styled';
 
 const StyledPropertyBoxItem = styled.div`
+  align-items: center;
   display: flex;
   gap: ${({ theme }) => theme.spacing(2)};
+  height: 32px;
 `;
 
 const StyledIconContainer = styled.div`