Enterprise Collaboration SaaS UI Redesign

Using the reference UI screenshot as a guide, redesign the enterprise collaboration software into a clean, modern SaaS product mockup while preserving the [MPLUS Link] branding, the dark navy left sidebar navigation, and core functions. Present a polished 2-column by 3-row grid showing exactly six redesigned screens: 1) a welcome/login screen featuring a large hero card, Japanese headline "[社外パートナー連携を、招待制の専用ワークスペースで一元化]", login tabs, and a desktop monitor graphic; 2) a project bridge chat interface with right-aligned message cards, action chips, and a message composer; 3) a team list view simplified into two clean team cards; 4) a materials and document management screen with file upload controls, search/filter inputs, and file list rows; 5) a shared collaboration room titled "[MPI 共同開発ルーム]" with a project overview card and member status list; 6) an admin user management screen titled "[ユーザー管理]" with user rows and a detail panel. Style: spacious modern Japanese enterprise SaaS UI, pale blue-gray background, white rounded cards, soft drop shadows, subtle dividers, and clean blue and green accent buttons, with consistent sidebar navigation across all screens.