Claude
59c7859bd4
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01GYeokZtSmqg42ZGWsLXX2C
243 lines
10 KiB
Markdown
243 lines
10 KiB
Markdown
# Glassmorphism Recipes
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Copy-paste recipes for frosted translucent panels, the "edge of glass" highlight, animated liquid-glass refraction, and the reduced-transparency fallback. All standalone CSS + optional inline SVG — no build step.
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## 1. The base glass card
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The four ingredients of believable glass: **blur** (frost), **translucency** (you see through it), **edge highlight** (light catches the rim), **layered shadow** (it floats). Plus a touch of `saturate()` so the backdrop reads vivid through the frost.
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```css
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.glass {
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/* translucency — never fully opaque, never fully clear */
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background: rgba(255, 255, 255, 0.12);
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/* frost: blur the backdrop, lift saturation so color survives the blur */
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backdrop-filter: blur(16px) saturate(160%);
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-webkit-backdrop-filter: blur(16px) saturate(160%); /* Safari still needs the prefix */
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border-radius: 20px;
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/* edge of glass: a hairline border slightly brighter than the fill */
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border: 1px solid rgba(255, 255, 255, 0.25);
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/* depth: ambient drop + a top inner highlight + a bottom inner shade */
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box-shadow:
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0 8px 32px rgba(0, 0, 0, 0.25),
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inset 0 1px 0 rgba(255, 255, 255, 0.35),
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inset 0 -1px 0 rgba(0, 0, 0, 0.12);
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}
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```
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Tuning by tier:
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- **Light frost** (UI chrome over content): `blur(8–12px)`, alpha `0.08–0.14`.
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- **Heavy frost** (modal scrim, login card): `blur(24–40px)`, alpha `0.10–0.18`.
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- Dark glass: swap the fill to `rgba(0,0,0,0.3)` and the top inner highlight to a softer white.
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`backdrop-filter` only has anything to blur if there is content **behind** the element — it must overlap a busy background (image, gradient, video). On a flat color it looks like a plain translucent box.
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## 2. The specular edge highlight (the rim of light)
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A single border is flat. Real glass catches a bright sweep along the top-left edge and falls off. Layer a soft conic/linear highlight via a pseudo-element with a masked border.
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```css
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.glass {
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position: relative;
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isolation: isolate; /* keep the highlight blend local */
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}
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.glass::before {
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content: "";
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position: absolute;
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inset: 0;
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border-radius: inherit;
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padding: 1px; /* border thickness */
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background: linear-gradient(
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135deg,
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rgba(255, 255, 255, 0.7),
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rgba(255, 255, 255, 0) 40%,
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rgba(255, 255, 255, 0) 60%,
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rgba(255, 255, 255, 0.25)
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);
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/* mask trick: show only the 1px ring, punch out the interior */
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-webkit-mask:
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linear-gradient(#000 0 0) content-box,
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linear-gradient(#000 0 0);
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-webkit-mask-composite: xor;
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mask-composite: exclude;
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pointer-events: none;
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}
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```
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This gives the panel a lit top-left corner and a dim bottom-right, the cue the brain reads as "curved glass under a light."
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## 3. Kill banding with grain
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Heavy `blur()` over a smooth gradient produces visible color **banding** (stepped contour lines). A faint noise overlay dithers it away.
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```css
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.glass::after {
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content: "";
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position: absolute;
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inset: 0;
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border-radius: inherit;
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pointer-events: none;
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opacity: 0.04; /* barely there */
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mix-blend-mode: overlay;
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background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='120' height='120'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='2'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
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}
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```
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`feTurbulence` generates the noise tile inline — no asset file. Keep opacity ≤ 0.06 or it reads as texture, not dither.
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## 4. Motion: animate the glass on hover / enter / scroll
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Animate the *qualities* of the glass, not its geometry. Frost deepening and the highlight brightening on hover reads as the panel "leaning into the light."
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```css
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.glass {
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transition:
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backdrop-filter 0.4s ease,
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background 0.4s ease,
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box-shadow 0.4s ease,
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transform 0.4s cubic-bezier(0.16, 1, 0.3, 1);
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}
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.glass:hover {
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backdrop-filter: blur(24px) saturate(180%);
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background: rgba(255, 255, 255, 0.18);
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transform: translateY(-4px);
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box-shadow:
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0 16px 48px rgba(0, 0, 0, 0.3),
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inset 0 1px 0 rgba(255, 255, 255, 0.5);
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}
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```
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Caveat: animating `backdrop-filter` itself is the most expensive thing here — the backdrop is re-sampled and re-blurred every frame. If hover feels janky, animate only `transform` + `box-shadow` + `background` (cheaper) and snap the blur, or keep the blur change small.
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**Entrance** (frost resolving in) reads beautifully with `@starting-style`:
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```css
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.glass[data-enter] {
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transition: opacity 0.5s ease, backdrop-filter 0.6s ease, transform 0.5s ease;
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}
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@starting-style {
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.glass[data-enter] {
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opacity: 0;
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backdrop-filter: blur(0px) saturate(100%);
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transform: translateY(16px) scale(0.98);
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}
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}
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```
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**Specular sweep** — a moving glint across the surface on hover or as an ambient loop:
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```css
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.glass .sweep {
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position: absolute; inset: 0; border-radius: inherit; overflow: hidden; pointer-events: none;
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}
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.glass .sweep::before {
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content: ""; position: absolute; top: 0; left: -60%; width: 50%; height: 100%;
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background: linear-gradient(105deg, transparent, rgba(255,255,255,0.35), transparent);
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transform: skewX(-15deg);
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animation: sweep 4s ease-in-out infinite;
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}
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@keyframes sweep { 0%,100% { left: -60%; } 50% { left: 110%; } }
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```
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## 5. Liquid glass — SVG refraction (the 2026 look)
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Apple-style "liquid glass" bends the background as if seen through a thick, wobbling lens. Drive a `feDisplacementMap` from animated `feTurbulence` and apply it via `filter` (note: `filter`, not `backdrop-filter` — it distorts the element's own rendered content; layer it over a `backdrop-filter` frost for the full effect).
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```html
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<svg width="0" height="0" style="position:absolute">
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<filter id="liquid-glass">
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<feTurbulence type="fractalNoise" baseFrequency="0.008 0.012"
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numOctaves="2" seed="3" result="noise">
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<!-- animate the field so the refraction slowly churns -->
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<animate attributeName="baseFrequency"
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dur="18s" values="0.008 0.012; 0.012 0.008; 0.008 0.012"
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repeatCount="indefinite"/>
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</feTurbulence>
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<feDisplacementMap in="SourceGraphic" in2="noise"
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scale="22" xChannelSelector="R" yChannelSelector="G"/>
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</filter>
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</svg>
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```
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```css
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.liquid {
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backdrop-filter: blur(6px) saturate(150%); /* light frost under the refraction */
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filter: url(#liquid-glass); /* the lens distortion */
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}
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```
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Knobs:
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- `scale` on `feDisplacementMap` = refraction strength. 8–14 = subtle ripple; 20–30 = pronounced lens; >40 = molten.
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- Lower `baseFrequency` = larger, slower waves (more "liquid"); higher = tight, busy ripples.
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- Animate `baseFrequency` (above) or `scale` for a living surface. Keep `dur` long (12–20s) so it breathes rather than shimmers.
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Cost warning: SVG displacement filters are heavy and force off-GPU paths in some browsers. Use on **one** hero element, not a grid of cards. Test on a mid-range laptop; drop to plain `backdrop-filter` if frames stutter.
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## 6. Performance — backdrop-filter is expensive
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- Each `backdrop-filter` element re-samples and blurs everything behind it. **Limit the count** — a dozen glass cards on screen will tank scroll FPS.
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- Promote heavy glass to its own compositor layer: `transform: translateZ(0)` or `will-change: transform` (remove `will-change` after the animation; leaving it on wastes memory).
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- Avoid stacking `backdrop-filter` elements over each other (nested blur re-blurs the blur — quadratic cost).
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- Prefer animating `transform`/`opacity`/`box-shadow` over animating the blur radius. If you must animate blur, keep the radius delta small.
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- Big blur radii (>40px) over large areas are the single worst case; cap the radius and the panel size.
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## 7. Accessibility — non-negotiable
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Glass is decorative; the content on it must stay legible and the effect must be defeatable.
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**Honor reduced transparency and reduced motion** — fall back to a solid, opaque panel:
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```css
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@media (prefers-reduced-transparency: reduce) {
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.glass {
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background: #1a1a2e; /* solid, accessible panel */
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backdrop-filter: none;
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-webkit-backdrop-filter: none;
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border-color: rgba(255, 255, 255, 0.15);
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}
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.glass::after { display: none; } /* drop grain/noise */
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}
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@media (prefers-reduced-motion: reduce) {
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.glass, .glass .sweep::before { transition: none; animation: none; }
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.liquid { filter: none; } /* stop the churning refraction */
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}
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```
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**Contrast over busy backgrounds.** Translucent panels over photos can drop text below WCAG contrast. Defenses:
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- Put a contrast floor *under* the text: a semi-opaque scrim or a darkening gradient inside the panel.
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- Add `text-shadow: 0 1px 2px rgba(0,0,0,0.4)` to body text on glass.
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- Target ≥ 4.5:1 for body text, ≥ 3:1 for large text — and verify against the *brightest* region of the backdrop, not the average.
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**Feature fallback** for browsers without `backdrop-filter`:
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```css
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@supports not (backdrop-filter: blur(1px)) {
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.glass { background: rgba(30, 30, 50, 0.85); } /* opaque-enough fallback */
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}
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```
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## 8. Standalone freeze harness
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Glass demos verify by *state* (rest / hover / enter) and *time* (the sweep/refraction loop). Wire both so a screenshot lands deterministically:
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```html
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<script>
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const p = new URLSearchParams(location.search);
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const state = p.get("state"); // ?state=hover → force the hover look
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if (state) document.documentElement.dataset.state = state;
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const t = p.get("t"); // ?t=2 → freeze CSS animations at 2s
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if (t !== null) {
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document.getAnimations().forEach(a => { a.currentTime = parseFloat(t) * 1000; a.pause(); });
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// SVG SMIL (the <animate>): pin the refraction frame too
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document.querySelector("svg")?.pauseAnimations?.();
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document.querySelector("svg")?.setCurrentTime?.(parseFloat(t));
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}
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window.__ready = true;
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</script>
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```
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CSS drives the forced state: `:root[data-state="hover"] .glass { /* hover values */ }`.
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---
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Frosted glass that reads as glass — blur, edge light, and refraction, with a clean fallback. Built by **[iart.ai](https://iart.ai/?utm_source=github&utm_medium=readme&utm_campaign=web-animation-skills&utm_content=skill_footer&utm_term=glassmorphism)** — the AI motion agent for editable, on-brand motion graphics.
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