HTMLify

*,
*:after,
*:before {
    box-sizing: border-box;
}

:root {
    --transition: 0.25s;
    --spark: 1.8s;
}

body {
    --active: 0;
    background: hsl(260 calc(var(--active) * 97%) 6%);
    display: grid;
    place-items: center;
    min-height: 100vh;
    font-family: system-ui, sans-serif;
    transition: background var(--transition);
    overflow: hidden;
}

button {
    --cut: 0.1em;
    --active: 0;
    --bg:
        radial-gradient(40% 50% at center 100%,
            hsl(270 calc(var(--active) * 97%) 72% / var(--active)),
            transparent),
        radial-gradient(80% 100% at center 120%,
            hsl(260 calc(var(--active) * 97%) 70% / var(--active)),
            transparent),
        hsl(260 calc(var(--active) * 97%) calc((var(--active) * 44%) + 12%));
    background: var(--bg);
    font-size: 2rem;
    font-weight: 500;
    border: 0;
    cursor: pointer;
    padding: 0.9em 1.3em;
    display: flex;
    align-items: center;
    gap: 0.25em;
    white-space: nowrap;
    border-radius: 100px;
    position: relative;
    box-shadow:
        0 0 calc(var(--active) * 6em) calc(var(--active) * 3em) hsl(260 97% 61% / 0.75),
        0 0.05em 0 0 hsl(260 calc(var(--active) * 97%) calc((var(--active) * 50%) + 30%)) inset,
        0 -0.05em 0 0 hsl(260 calc(var(--active) * 97%) calc(var(--active) * 60%)) inset;
    transition: box-shadow var(--transition), scale var(--transition), background var(--transition);
    scale: calc(1 + (var(--active) * 0.1));
}

button:active {
    scale: 1;
}

svg {
    overflow: visible !important;
}

.sparkle path {
    color: hsl(0 0% calc((var(--active, 0) * 70%) + var(--base)));
    transform-box: fill-box;
    transform-origin: center;
    fill: currentColor;
    stroke: currentColor;
    animation-delay: calc((var(--transition) * 1.5) + (var(--delay) * 1s));
    animation-duration: 0.6s;
    transition: color var(--transition);
}

button:is(:hover, :focus-visible) path {
    animation-name: bounce;
}

@keyframes bounce {

    35%,
    65% {
        scale: var(--scale);
    }
}

.sparkle path:nth-of-type(1) {
    --scale: 0.5;
    --delay: 0.1;
    --base: 40%;
}

.sparkle path:nth-of-type(2) {
    --scale: 1.5;
    --delay: 0.2;
    --base: 20%;
}

.sparkle path:nth-of-type(3) {
    --scale: 2.5;
    --delay: 0.35;
    --base: 30%;
}

button:before {
    content: "";
    position: absolute;
    inset: -0.25em;
    z-index: -1;
    border: 0.25em solid hsl(260 97% 50% / 0.5);
    border-radius: 100px;
    opacity: var(--active, 0);
    transition: opacity var(--transition);
}

.spark {
    position: absolute;
    inset: 0;
    border-radius: 100px;
    rotate: 0deg;
    overflow: hidden;
    mask: linear-gradient(white, transparent 50%);
    animation: flip calc(var(--spark) * 2) infinite steps(2, end);
}

@keyframes flip {
    to {
        rotate: 360deg;
    }
}

.spark:before {
    content: "";
    position: absolute;
    width: 200%;
    aspect-ratio: 1;
    top: 0%;
    left: 50%;
    z-index: -1;
    translate: -50% -15%;
    rotate: 0;
    transform: rotate(-90deg);
    opacity: calc((var(--active)) + 0.4);
    background: conic-gradient(from 0deg,
            transparent 0 340deg,
            white 360deg);
    transition: opacity var(--transition);
    animation: rotate var(--spark) linear infinite both;
}

.spark:after {
    content: "";
    position: absolute;
    inset: var(--cut);
    border-radius: 100px;
}

.backdrop {
    position: absolute;
    inset: var(--cut);
    background: var(--bg);
    border-radius: 100px;
    transition: background var(--transition);
}

@keyframes rotate {
    to {
        transform: rotate(90deg);
    }
}



@supports(selector(:has(:is(+ *)))) {
    body:has(button:is(:hover, :focus-visible)) {
        --active: 1;
        --play-state: running;
    }

    .bodydrop {
        display: none;
    }
}

button:is(:hover, :focus-visible)~ :is(.bodydrop, .particle-pen) {
    --active: 1;
    --play-state: runnin;
}

.bodydrop {
    background: hsl(260 calc(var(--active) * 97%) 6%);
    position: fixed;
    inset: 0;
    z-index: -1
}



button:is(:hover, :focus-visible) {
    --active: 1;
    --play-state: running;
}


.sparkle-button {
    position: relative;
}

.particle-pen {
    position: absolute;
    width: 200%;
    aspect-ratio: 1;
    top: 50%;
    left: 50%;
    translate: -50% -50%;
    mask: radial-gradient(white, transparent 65%);
    z-index: -1;
    opacity: var(--active, 0);
    transition: opacity var(--transition);
}

.particle {
    fill: white;
    width: calc(var(--size, 0.25) * 1rem);
    aspect-ratio: 1;
    position: absolute;
    top: calc(var(--y) * 1%);
    left: calc(var(--x) * 1%);
    opacity: var(--alpha, 1);
    animation: float-out calc(var(--duration, 1) * 1s) calc(var(--delay) * -1s) infinite linear;
    transform-origin: var(--origin-x, 1000%) var(--origin-y, 1000%);
    z-index: -1;
    animation-play-state: var(--play-state, paused);
}

.particle path {
    fill: hsl(0 0% 90%);
    stroke: none;
}

.particle:nth-of-type(even) {
    animation-direction: reverse;
}

@keyframes float-out {
    to {
        rotate: 360deg;
    }
}

button svg {
    inline-size: 1.25em;
    translate: 0;
}