The Logic of Interface
Work in Progress ~24% Completed

A book on the principles that connect visual thinking and engineering logic.

Four ideas this book is built around

The four principles I keep coming back to, in the writing and in the build.

01

Systems over screens

Design is not a collection of pages. It's a system of relationships, constraints, and patterns.

02

Precision & craft

Precision is not perfectionism - it's communication through detail.

03

Constraints on creativity

The browser is not a limitation. CSS, layout algorithms, and performance boundaries shape the work.

04

Authorship in code

Choices in implementation, architecture, and interaction define the experience just as much as any sketch or mockup.

COVERHardcover, 184 pages — limited run.

SPREAD 01Portfolio spread, two-column grid.

01 / 04

Chapters

100%  COMPLETED
PART I. FOUNDATIONS

What an interface actually is: a set of decisions, each with a cost. Where design intent becomes a constraint in code.

01 Decisions, not pixels p.12
02 The browser as material p.18
03 Constraints as language p.24
04 From intent to implementation p.30
100%  COMPLETED
PART II. SYSTEMS

Layout, type, colour and space as one interconnected structure, not isolated decisions made screen by screen.

01 Layout as structure p.38
02 Type as a system p.44
03 Colour and contrast rules p.50
04 Space and rhythm p.56
62%  IN PROGRESS
PART III. MOTION

Easing, transitions and timing as part of the interface's language — not decoration added at the end.

01 Easing as intent p.64
02 Transitions between states p.70
03 Motion as feedback p.76
04 Performance budgets p.82
NOT STARTED
PART IV. PRACTICE

Component architecture, working with a team, and keeping quality consistent as the codebase grows.

01 Component architecture p.90
02 Working with a team p.96
03 Design review, in code p.102
04 Keeping quality over time p.108
NOT STARTED
PART V. TOOLS

Choosing tools that speed up the work, without getting between you and the browser.

01 Choosing what to learn p.114
02 The editor and the browser p.118

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Book cover — The Logic of Interface

The Author

I've spent ten+ years moving between design and engineering. I started as a designer who learned to code out of frustration - I wanted more control over the final artifact. Over time, I realized the distinction between the two disciplines was largely organizational, not fundamental.

The best interfaces I've worked on were built by people who understood both sides: designers who could read code and reason about constraints, engineers who cared deeply about visual craft and user experience.

This book is an attempt to articulate what that integrated practice looks like. Not a tutorial on tools, but a way of thinking about interface design as a single discipline.

The audience is anyone who feels the gap between design and code and wants to close it - whether you're coming from design, engineering, or somewhere in between.

Simona Nasteva · Senior Software Engineer & Designer

simonanasteva.com

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