Improve design tokens

[jbpenrath]

Currently, design tokens are not really exhaustive and some customization are limited by this exhaustive weakness.

IMO, this world could be split in several parts:

1. First check component tokens consistency, identify weaknesses and add missing tokens
2. Then we should wonder if we could benefit to add a new design token layer between global and component layers.

• Global tokens --font-family-accent: 'Comic Sans MS'
• Contextual tokens --title-font-family: var(--font-family-accent)
• Component tokens --form-input-label-font-family: var(--title-font-family)