CSS3 Animation Tutorials

Introduction to CSS Animations

CSS Animations allow you to create complex animation sequences without relying on JavaScript or Flash. They are defined using the @keyframes rule and applied to elements using the animation property.

Core Concepts

• @keyframes: Defines the stages of an animation.
• animation: A shorthand property to set various animation properties like name, duration, timing function, delay, iteration count, direction, fill mode, and play state.

@keyframes Example

This defines an animation named "pulse" that scales an element up and down.

@keyframes pulse {
  0% {
    transform: scale(1);
    box-shadow: 0 0 0 0 rgba(0, 168, 168, 0.7);
  }
  70% {
    transform: scale(1.05);
    box-shadow: 0 0 0 15px rgba(0, 168, 168, 0);
  }
  100% {
    transform: scale(1);
    box-shadow: 0 0 0 0 rgba(0, 168, 168, 0);
  }
}

Applying the Animation

Here's how to apply the "pulse" animation to an element:

.animated-box {
  width: 150px;
  height: 150px;
  background-color: #00a8a8; /* accent-color */
  border-radius: 10px;
  display: flex;
  justify-content: center;
  align-items: center;
  font-size: 1.5rem;
  font-weight: bold;
  color: #f0f0f0; /* light-text */
  animation: pulse 2s infinite ease-in-out;
}

CSS Transitions vs. Animations

While similar, transitions and animations serve different purposes:

• Transitions: Used for animating property changes when an element's state changes (e.g., on hover, focus, or class change). They are simpler, reacting to state changes.
• Animations: Provide more control over complex, multi-step sequences that can run independently of state changes, defined by @keyframes.

Transition Example (Hover Effect)

This box smoothly changes color and shape when you hover over it.

.transition-example {
  width: 100px;
  height: 100px;
  background-color: #0078d4; /* primary-color */
  margin: 20px auto;
  transition: background-color 0.5s ease-in-out, transform 0.5s ease-in-out;
}

.transition-example:hover {
  background-color: #00a8a8; /* accent-color */
  transform: rotate(45deg) scale(1.2);
}

Key Animation Properties

Understanding the various properties that control animations:

• animation-name: Specifies the name of the @keyframes rule to apply.
• animation-duration: Sets how long the animation should take to complete.
• animation-timing-function: Defines the speed curve (e.g., ease, linear, ease-in-out).
• animation-delay: Sets a delay before the animation starts.
• animation-iteration-count: Specifies how many times the animation should repeat (e.g., infinite).
• animation-direction: Determines whether the animation should play forwards, backwards, or alternate.
• animation-fill-mode: Defines which styles are applied to the element before and after the animation (e.g., forwards, backwards, both).
• animation-play-state: Allows pausing and resuming animations (e.g., paused, running).

animation-name and animation-fill-mode Example

This box animates in from the right and stays visible.

.animation-name-example {
  width: 100px;
  height: 100px;
  background-color: #00a8a8; /* accent-color */
  margin: 20px auto;
  animation: slideInRight 1.5s forwards;
}

@keyframes slideInRight {
  from { transform: translateX(100%); opacity: 0; }
  to { transform: translateX(0); opacity: 1; }
}

animation-iteration-count and animation-direction Example

This circular element smoothly changes its gradient colors and alternates direction.

.keyframe-example {
  width: 120px;
  height: 120px;
  background: linear-gradient(45deg, #0078d4, #00a8a8);
  border-radius: 50%;
  margin: 20px auto;
  animation: colorChange 4s infinite alternate;
}

@keyframes colorChange {
  0% { background: linear-gradient(45deg, #0078d4, #00a8a8); }
  50% { background: linear-gradient(45deg, #00a8a8, #0078d4); }
  100% { background: linear-gradient(45deg, #0078d4, #00a8a8); }
}

Advanced Techniques & Best Practices

• Combining Properties: Use the shorthand animation property for cleaner code.
• Performance: Animate properties that trigger fewer layout recalculations (e.g., transform and opacity) for better performance. Avoid animating properties like width, height, margin, or top/left if possible.
• Accessibility: Provide options to disable animations for users sensitive to motion (e.g., using @media (prefers-reduced-motion: reduce)).

Explore further resources on MDN Web Docs for comprehensive details on CSS animations and transitions.

MDN CSS Animations Guide