Responsive

Mobile-First Approach

Start with mobile styles, add complexity for larger screens.

/* Base: Mobile */
.card {
  padding: var(--space-md);
}

/* Enhancement: Tablet+ */
@media (min-width: 768px) {
  .card {
    padding: var(--space-lg);
  }
}

/* Enhancement: Desktop+ */
@media (min-width: 1024px) {
  .card {
    padding: var(--space-xl);
  }
}

Breakpoints

Breakpoint	Min-width	Target
sm	640px	Large phones
md	768px	Tablets
lg	1024px	Laptops
xl	1280px	Desktops
2xl	1536px	Large screens

Responsive Typography

Font sizes that adapt:

.title {
  font-size: var(--text-2xl);
}

@media (min-width: 768px) {
  .title {
    font-size: var(--text-3xl);
  }
}

@media (min-width: 1024px) {
  .title {
    font-size: var(--text-4xl);
  }
}

Or use fluid typography:

.title {
  font-size: clamp(1.5rem, 4vw, 2.5rem);
}

Responsive Spacing

Scale spacing proportionally:

Context	Mobile	Tablet	Desktop
Section padding	--space-lg	--space-xl	--space-2xl
Card padding	--space-md	--space-lg	--space-lg
Stack gap	--space-sm	--space-md	--space-md

Layout Patterns

Stack → Grid

.features {
  display: grid;
  gap: var(--space-lg);
  grid-template-columns: 1fr;
}

@media (min-width: 768px) {
  .features {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 1024px) {
  .features {
    grid-template-columns: repeat(3, 1fr);
  }
}

Sidebar → Stack

.layout {
  display: flex;
  flex-direction: column;
}

@media (min-width: 1024px) {
  .layout {
    flex-direction: row;
  }
  
  .sidebar {
    width: 280px;
    flex-shrink: 0;
  }
  
  .main {
    flex: 1;
  }
}

Touch Targets

Minimum touch target size: 44×44px

.button {
  min-height: 44px;
  min-width: 44px;
  padding: var(--space-sm) var(--space-md);
}

Testing Checklist

• Works on 320px width (iPhone SE)
• Touch targets are 44px minimum
• Text is readable without zooming
• No horizontal scroll
• Forms are usable with thumb
• Modals work on small screens