Mário Sérgio Dias · UX/UI · Recife
Product Designer:research, UX strategyand interface design
From user research to a tested prototype, with decisions guided by design principles and AI to speed up the process.
See my workIllustration: scattered, hollow, rotated squares on the left organize into a regular grid on the right; a yellow square marks the decision. The squares turn toward the visitor’s cursor and, near it, the loose ones line up.
Work
Research · Design thinking · 2026
ALINHA Sphere
Why do young people fall for Instagram ad scams? Research, interviews, personas, journeys and 14 A/B tests led to a proposed anti-phishing guideline.
- Context
- CISSA Summer Job, CESAR
- Contribution
- Research, 6-3-5 ideation and test analysis
- Validation
- 14 A/B tests in a simulated feed
Web platform · Public sector · 2025
SefAIz
An MVP proposal for SEFAZ-PE, Pernambuco’s finance department, that teaches entrepreneurs how to access tax incentives, with learning paths, an eligibility simulator and an AI assistant.
- Context
- CESAR & FACEPE extension project
- Contribution
- MVP, flows, interface and client relations
- AI
- Features proposed in the product
Web platform · Tax education · 2025
Fiscolab
The evolution of SefAIz: an AI-powered tax education platform built as a team with SEFAZ-PE. I worked from defining and prototyping the MVP to client alignment, including flows, interfaces and features.
- Context
- CESAR & FACEPE extension project
- Contribution
- MVP, flows, interfaces and client relations
- Outcome
- Paper at IHIET-AI 2026, Spain
Dashboard · Team management · 2025
Productivity dashboard
A dashboard for managers to see their team’s workload, hours and bottlenecks, built on the Kanban flow the team already uses.
- Context
- UX take-home challenge
- Contribution
- Discovery, architecture and UI, solo
- Highlight
- From V1 to V2
Mobile app · Health · 2026
Klep
An app for booking medical appointments and tests, designed around usability heuristics and tested with users.
- Context
- CESAR School, team project
- Contribution
- Team flow; my part was the screen design
- Validation
- User testing
Other work
Visual identity and independent projects.
Visual identity · Freelance · 2026
Sollar Gestão Condominial
A brand that combines building and sun: the light falling on Recife’s buildings becomes a symbol of security and warmth.
View project
Game · Independent project · In production
Catarina
A narrative game about a vampire in conflict with her own ethics. I created the game design and the script and collaborated on art direction.
View projectLess guessing, more why
Three ways of thinking that go together in every project I do.
Curiosity with method
I like questions more than ready-made answers
Before designing, I want to understand who uses it, in what context and with what constraints. Research is how I question assumptions, mine included, and find the problem worth solving.
Criteria over taste
A good interface can explain its choices
Design principles, heuristics, UX methods and interaction patterns are the lenses I use to decide and review every screen. If a choice can’t be justified by the problem and the context, it goes back on the table.
Responsible AI
AI speeds up the work, but critical thinking always comes first
I use AI to broaden research, synthesis, exploration and execution: it lets me test more and see better. Checking what it delivers and owning the decisions is my job, not its job.
Research and publications
Papers I wrote with classmates and professors at CESAR School.
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Heurísticas de Nielsen, taxonomias de dark patterns e ECA Digital: uma matriz analítica para a discussão da regulação de interfaces digitais
In Portuguese. A matrix that cross-references usability heuristics, deceptive design patterns and Brazil’s Digital Statute of Children and Adolescents (ECA Digital), to help recognize when an interface takes away its users’ autonomy.
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Fiscolab: Co-Creation, Artificial Intelligence, and User-Centered Design in the Development of Educational Fiscal Solutions
How co-creation with SEFAZ-PE, AI and user-centered design shaped Fiscolab, a tax education platform.
Hi, I’m Mário!
Before design, I studied law. I always loved the humanities, but something was missing: I wanted to be in motion, challenging and being challenged. That restlessness brought me to design, and today I’m making the switch as a Design undergraduate at CESAR School, sure that I’ve found my place.
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I’m interested in Product Design and UX, as well as service design, process design, agile methods and data-driven strategic planning. I also use AI in my process, always with critical thinking: to me, it’s a partner that expands my reasoning, not a shortcut that replaces it. I’m inquisitive and creative: I like proposing new ideas while keeping my feet on the ground of the project. After all, you don’t always need to reinvent the wheel, right?
Outside Figma, I love games, nerd culture, tech, sports and cats (who, by the way, love reviewing my layouts by sitting on the keyboard). All of this makes me a more curious designer, and that curiosity is what I bring to every product I help build.
- UX Strategy
- Product Thinking
- UX/UI Design
- Interaction Design
- Prototyping
- User research
- AI-assisted creation
Let’s bring your idea to life
I’m open to roles and freelance projects in product design, UX/UI, service design and process design.
- Available for
- Roles and freelance work
- Location
- Recife, Brazil