Skills Design & Creative Flat Design UI Style Guide

Flat Design UI Style Guide

v20261103
flat-design
A comprehensive guide for implementing Flat Design in web and mobile applications. Focuses on zero depth, sharp geometries, and high contrast solid colors without shadows or gradients. Includes CSS, SwiftUI, Flutter, and React Native code examples for creating clean, modern interfaces.
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Overview

Flat Design

"Digital surfaces should look digital. Embrace the 2D plane."

When to Use

Use this sub-style when the user's request matches the aesthetic described above. This is a child reference of the design-it skill and is not meant to be triggered directly.

Core Principles

  1. Zero Depth: Absolutely no drop shadows, bevels, gradients, or 3D effects. Everything sits on the same z-axis.
  2. Sharp & Simple Geometries: Perfect circles, sharp rectangles. No complex organic shapes.
  3. High Contrast Solid Colors: Rely on stark contrast between solid blocks of color to delineate space.

Visual DNA

  • Colors: Pairs well with Industrial Chic or Modern Editorial. Avoid gradients entirely.
  • Typography: Strong, highly legible sans-serifs (e.g., Roboto, Open Sans). Keep it medium to bold.
  • Icons: Solid, monochromatic, glyph-style icons without intricate details.

Web Implementation

  • Rely entirely on background colors and borders for structure.
  • CSS Example:
.flat-card {
  background-color: var(--secondary-base);
  border: 2px solid var(--primary-text);
  border-radius: 0; /* Sharp corners preferred */
  padding: 32px;
  /* NO box-shadow */
}
.flat-btn {
  background-color: var(--cta-highlight);
  color: #fff;
  border: none;
  padding: 16px 32px;
  font-weight: 700;
  text-transform: uppercase;
  transition: opacity 0.2s;
}
.flat-btn:hover {
  opacity: 0.8; /* Only change opacity or solid color on hover, no lifting */
}

App Implementation

SwiftUI

struct FlatCard: View {
    var body: some View {
        VStack(alignment: .leading, spacing: 16) {
            Text("Card Title")
                .font(.system(size: 18, weight: .bold))
            
            Text("Content without any depth effects.")
                .font(.system(size: 15))
                .foregroundColor(.secondary)
            
            Button(action: {}) {
                Text("ACTION")
                    .font(.system(size: 14, weight: .bold))
                    .foregroundColor(.white)
                    .padding(.horizontal, 24)
                    .padding(.vertical, 12)
                    .background(Color.blue)
                    // No cornerRadius — sharp edges
            }
        }
        .padding(24)
        .background(Color(.secondarySystemBackground))
        // NO .shadow() — ever
        // NO .cornerRadius() — sharp rectangles
        .overlay(
            Rectangle().stroke(Color.primary.opacity(0.2), lineWidth: 1)
        )
    }
}
  • Never use .shadow() or .cornerRadius(). Elements are flat rectangles.
  • Use .overlay(Rectangle().stroke(...)) for visible borders instead of shadows to delineate space.
  • Hover/tap states should only change opacity or swap a solid background color.

Flutter

class FlatCard extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Container(
      padding: const EdgeInsets.all(24),
      decoration: BoxDecoration(
        color: Colors.grey[100],
        border: Border.all(color: Colors.black26, width: 1),
        // borderRadius: NONE — sharp corners
        // boxShadow: NONE — zero depth
      ),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          const Text('Card Title',
            style: TextStyle(fontSize: 18, fontWeight: FontWeight.bold)),
          const SizedBox(height: 16),
          const Text('Content without any depth effects.',
            style: TextStyle(fontSize: 15, color: Colors.black54)),
          const SizedBox(height: 16),
          ElevatedButton(
            onPressed: () {},
            style: ElevatedButton.styleFrom(
              elevation: 0,           // Critical: no shadow
              backgroundColor: const Color(0xFF125A94),
              foregroundColor: Colors.white,
              shape: const RoundedRectangleBorder(
                borderRadius: BorderRadius.zero, // Sharp corners
              ),
              padding: const EdgeInsets.symmetric(horizontal: 24, vertical: 12),
            ),
            child: const Text('ACTION',
              style: TextStyle(fontWeight: FontWeight.bold, letterSpacing: 1)),
          ),
        ],
      ),
    );
  }
}
  • Override ThemeData globally to kill all elevation:

```dart
ThemeData(
cardTheme: const CardThemeData(elevation: 0, shape: RoundedRectangleBorder()),
appBarTheme: const AppBarTheme(elevation: 0),
floatingActionButtonTheme: const FloatingActionButtonThemeData(elevation: 0),
)
```

  • Use Container with BoxDecoration instead of Card widget to avoid default elevation.

React Native

const FlatCard = () => (
  <View style={{
    padding: 24,
    backgroundColor: '#F0F0F0',
    borderWidth: 1,
    borderColor: '#CCCCCC',
    // NO borderRadius
    // NO elevation or shadow properties
  }}>
    <Text style={{ fontSize: 18, fontWeight: '700', marginBottom: 16 }}>
      Card Title
    </Text>
    <Text style={{ fontSize: 15, color: '#666', marginBottom: 16 }}>
      Content without any depth effects.
    </Text>
    <TouchableOpacity
      style={{
        backgroundColor: '#125A94',
        paddingHorizontal: 24,
        paddingVertical: 12,
        alignSelf: 'flex-start',
        // NO borderRadius, NO elevation
      }}
      activeOpacity={0.7}
    >
      <Text style={{ color: '#FFF', fontWeight: '700', letterSpacing: 1 }}>
        ACTION
      </Text>
    </TouchableOpacity>
  </View>
);
  • Explicitly set elevation: 0 and remove ALL shadow properties (shadowColor, shadowOffset, etc.).
  • If using React Native Paper, override the theme: const theme = { ...DefaultTheme, roundness: 0, }.
  • Tap feedback should change backgroundColor directly, not add glow or lift.

Jetpack Compose

@Composable
fun FlatCard() {
    Column(
        modifier = Modifier
            .background(Color(0xFFF0F0F0))
            .border(1.dp, Color(0xFFCCCCCC))
            .padding(24.dp)
    ) {
        Text("Card Title", fontSize = 18.sp, fontWeight = FontWeight.Bold)
        Spacer(Modifier.height(16.dp))
        Text("Content without any depth effects.",
            fontSize = 15.sp, color = Color(0xFF666666))
        Spacer(Modifier.height(16.dp))
        Button(
            onClick = {},
            shape = RectangleShape,  // Sharp corners
            elevation = ButtonDefaults.buttonElevation(
                defaultElevation = 0.dp,  // No shadow
                pressedElevation = 0.dp,
            ),
            colors = ButtonDefaults.buttonColors(containerColor = Color(0xFF125A94)),
            contentPadding = PaddingValues(horizontal = 24.dp, vertical = 12.dp),
        ) {
            Text("ACTION", fontWeight = FontWeight.Bold, letterSpacing = 1.sp)
        }
    }
}
  • Override MaterialTheme shapes: shapes = Shapes(small = RectangleShape, medium = RectangleShape, large = RectangleShape).
  • Set all elevation to 0.dp on Card, TopAppBar, and FloatingActionButton.
  • Use Modifier.border() instead of elevation to separate UI regions.

Do's and Don'ts

  • DO: Use solid, contrasting borders to separate overlapping elements.
  • DON'T: Use any transparency (rgba) or blur effects.

Limitations

  • This is a styling reference and does not replace environment-specific validation, accessibility testing, or expert review.
  • Ensure appropriate contrast ratios and responsive behaviors are verified separately.
Info
Name flat-design
Version v20261103
Size 7.57KB
Updated At 2026-11-04
Language