Flat Design 2.0 Chat Conversation

Act like a frontend developer with 15 years of experience. I want the exact same UI with 95-99% similarity.

Platform: This is a RESPONSIVE design — it should work on both mobile and desktop. Use mobile layout patterns (bottom nav, stacked content) for mobile, and desktop layout patterns (sidebar/nav bar, wider content areas) for web.

Design a chat screen with a header showing avatar, name and online status, alternating incoming and outgoing message bubbles with timestamps, and a rounded input bar with an attach icon and a send button.

Visual style — Flat Design 2.0:
Large soft-color geometric illustration blocks with simple rounded blob-people figures as decorative accents. Flat solid-fill cards at 12px radius, no shadow, no gradient, no texture. Confident single-weight sans-serif. Clean, friendly, corporate-startup illustration style.

Color palette — Teal Cream:
Background #FFFCF5, surfaces #F6F1E4. Text #20342E. Illustration teal #2A9D8F and cream #FFF3D6.

Typography — use these exact font families:
- Headings / display: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif

Commit fully to this style — it should be unmistakable at a glance. Use realistic content, not placeholder text. Keep animations smooth (200ms ease-out).