CSS in 2026: Anchor Positioning, Scroll-Driven Animations, @starting-style & More

CSS in 2026 is more powerful than ever, with features that previously required JavaScript now built natively into the language. From anchor positioning to scroll-driven animations, here's everything you need to know.

🎨 The Modern CSS Feature Set

• Anchor Positioning — Position elements relative to any other element
• Scroll-Driven Animations — Animate based on scroll position, no JS needed
• @starting-style — Animate elements on first render
• Container Queries — Style based on parent size, not viewport
• :has() Selector — The "parent selector" CSS always needed
• View Transitions API — Smooth page transitions natively

1. Anchor Positioning

Position tooltips, popovers, and dropdowns relative to any element — no JavaScript positioning libraries needed.

/* Define the anchor */
.trigger-button {
  anchor-name: --my-anchor;
}

/* Position relative to the anchor */
.tooltip {
  position: fixed;
  position-anchor: --my-anchor;

  /* Place below the anchor, centred horizontally */
  top: anchor(bottom);
  left: anchor(center);
  translate: -50% 8px;

  /* Auto-flip if it overflows the viewport */
  position-try-fallbacks: flip-block, flip-inline;
}

/* Works with any element pair — no wrapper needed! */

2. Scroll-Driven Animations

Create parallax effects, progress indicators, and reveal animations driven purely by scroll — zero JavaScript.

/* Progress bar that fills as you scroll the page */
.reading-progress {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 4px;
  background: linear-gradient(to right, #3b82f6, #8b5cf6);
  transform-origin: left;
  animation: grow-progress linear;
  animation-timeline: scroll();
}

@keyframes grow-progress {
  from { transform: scaleX(0); }
  to   { transform: scaleX(1); }
}

/* Fade-in elements as they scroll into view */
.reveal-on-scroll {
  animation: fade-in linear both;
  animation-timeline: view();
  animation-range: entry 0% entry 100%;
}

@keyframes fade-in {
  from { opacity: 0; transform: translateY(40px); }
  to   { opacity: 1; transform: translateY(0); }
}

3. @starting-style — Entry Animations

Animate elements when they first appear in the DOM — perfect for dialogs, toasts, and dynamically added content.

/* Dialog with entry animation */
dialog[open] {
  opacity: 1;
  transform: scale(1);
  transition: opacity 0.3s, transform 0.3s, display 0.3s allow-discrete;

  @starting-style {
    opacity: 0;
    transform: scale(0.9);
  }
}

/* Toast notification that slides in */
.toast {
  translate: 0 0;
  opacity: 1;
  transition: translate 0.4s ease-out, opacity 0.4s;

  @starting-style {
    translate: 100% 0;
    opacity: 0;
  }
}

4. Container Queries

Style components based on their parent's size, not the viewport. This is the holy grail for component-based design.

/* Define a container */
.card-wrapper {
  container-type: inline-size;
  container-name: card;
}

/* Style based on container width */
@container card (min-width: 400px) {
  .card {
    display: grid;
    grid-template-columns: 200px 1fr;
    gap: 1rem;
  }

  .card-image {
    aspect-ratio: 1;
  }
}

@container card (max-width: 399px) {
  .card {
    display: flex;
    flex-direction: column;
  }

  .card-image {
    aspect-ratio: 16/9;
  }
}

5. The :has() Selector

Select parents based on their children. This was CSS's most requested feature for over a decade.

/* Style a form group that contains an invalid input */
.form-group:has(input:invalid) {
  border-color: red;
}

.form-group:has(input:invalid) .error-message {
  display: block;
}

/* Style a card differently if it has an image */
.card:has(img) {
  grid-template-rows: 200px auto;
}

.card:not(:has(img)) {
  padding-top: 2rem;
}

/* Dark mode toggle without JS */
html:has(#dark-mode:checked) {
  color-scheme: dark;
  --bg: #0f172a;
  --text: #e2e8f0;
}

6. View Transitions API

/* Smooth page transitions — works with MPA and SPA */
@view-transition {
  navigation: auto;
}

/* Customise the transition animation */
::view-transition-old(root) {
  animation: slide-out 0.3s ease-in;
}

::view-transition-new(root) {
  animation: slide-in 0.3s ease-out;
}

@keyframes slide-out {
  to { transform: translateX(-100%); opacity: 0; }
}

@keyframes slide-in {
  from { transform: translateX(100%); opacity: 0; }
}

/* Named transitions for specific elements */
.hero-image {
  view-transition-name: hero;
}
/* The hero image morphs smoothly between pages! */