Cloud Upload Bubbles

  <main>
    <div class="upload">
      <div class="upload__bubbles">
        <div class="upload__cloud-explode">
          <div class="upload__finish">
            <svg role="img" aria-label="Checkmark in circle" class="upload__check" viewBox="0 0 128 128" width="128" height="128">
              <g fill="none" stroke="hsl(223,90%,50%)" stroke-width="4" stroke-linecap="round" stroke-linejoin="round">
                <circle class="upload__check-ring" r="62" cx="64" cy="64" stroke-dasharray="389.56 389.56" stroke-dashoffset="389.56" transform="rotate(-90,64,64)" />
                <polyline class="upload__check-line" points="40,64 56,80 88,48" stroke-dasharray="68 68" stroke-dashoffset="68" />
              </g>
            </svg>
            <p class="upload__feedback">File has been uploaded successfully!</p>
            <button class="upload__button" type="button" data-reset>OK</button>
          </div>
        </div>
        <div class="upload__cloud-left"></div>
        <div class="upload__cloud-middle" data-circle></div>
        <div class="upload__cloud-right"></div>
      </div>
      <div aria-hidden="false">
        <div class="upload__progress" data-progress></div>
        <button class="upload__button" type="button" data-upload>Upload</button>
      </div>
    </div>
  </main>

* {
	border: 0;
	box-sizing: border-box;
	margin: 0;
	padding: 0;
}
:root {
	--hue: 223;
	--primary1: hsl(var(--hue),90%,5%);
	--primary9: hsl(var(--hue),90%,40%);
	--primary10: hsl(var(--hue),90%,50%);
	--primary11: hsl(var(--hue),90%,60%);
	--primary18: hsl(var(--hue),90%,90%);
	--trans-dur: 0.3s;
	font-size: calc(16px + (20 - 16) * (100vw - 320px) / (1280 - 320));
}
body,
button {
	font: 1em/1.5 "DM Sans", sans-serif;
}
body {
	background-color: var(--primary18);
	color: var(--primary1);
	height: 100vh;
	transition:
		background-color var(--trans-dur),
		color var(--trans-dur);
}
main {
	display: grid;
	overflow: hidden;
	place-items: center;
	height: 100%;
	min-height: 24.5em;
}
.upload,
.upload__finish {
	max-width: 17em;
}
.upload {
	padding: 1.5em;
	text-align: center;
	width: 100%;
}
.upload__button {
	background-color: var(--primary10);
	border-radius: 0.2em;
	color: hsl(0,0%,100%);
	padding: 0.75em 1.5em;
	width: 100%;
	transition: background-color 0.15s ease-in-out;
}
.upload__button:disabled {
	cursor: not-allowed;
	opacity: 0.5;
}
.upload__button:focus {
	outline: transparent;
}
.upload__button:not(:disabled):focus-visible,
.upload__button:not(:disabled):hover {
	background-color: var(--primary9);
}
.upload__bubbles {
	margin: 0 auto 3em auto;
	position: relative;
	height: 8em;
	width: 8em;
	z-index: 1;
}
.upload__bubble {
	--dur: 3s; /* to be overridden by JavaScript */
	position: absolute;
	top: 100%;
	left: 50%;
	width: 2em;
	height: 2em;
	transform: translateX(-50%);
	transform-origin: 50% 100%;
}
.upload__bubble:before {
	background-color: var(--primary11);
	border-radius: 50%;
	content: "";
	display: block;
	width: 100%;
	height: 100%;
}
.upload__check {
	display: block;
	margin: 0 auto 3em auto;
	width: 8em;
	height: 8em;
}
.upload__cloud-explode,
.upload__cloud-left,
.upload__cloud-middle,
.upload__cloud-right {
	background-color: hsl(0,0%,100%);
	position: absolute;
}
.upload__cloud-explode,
.upload__cloud-middle {
	border-radius: 50%;
}
.upload__cloud-explode {
	display: none;
	bottom: 0;
	left: 50%;
	width: 69em;
	height: 69em;
	transform: translate(-50%,1em) scale(0);
	transform-origin: 50% 100%;
	z-index: 1;
}
.upload__cloud-left,
.upload__cloud-middle,
.upload__cloud-right {
	bottom: 0;
}
.upload__cloud-left,
.upload__cloud-right {
	width: 6em;
}
.upload__cloud-left {
	border-radius: 2.5em 0 0 2.5em;
	right: 50%;
	height: 5em;
}
.upload__cloud-middle {
	overflow: hidden;
	position: absolute;
	left: 50%;
	width: 13em;
	height: 13em;
	transform: translate(-50%,0) scale(0.6);
	transform-origin: 50% 100%;
	z-index: 2;
}
.upload__cloud-right {
	border-radius: 0 3em 3em 0;
	left: 50%;
	height: 6em;
}
.upload__feedback {
	color: hsl(var(--hue),10%,5%);
	margin-bottom: 4.5em;
}
.upload__feedback,
.upload__feedback + .upload__button {
	opacity: 0;
	transform: translateY(100%);
}
.upload__finish {
	margin: auto;
	padding: 1.5em;
}
.upload__progress {
	opacity: 0;
}
.upload__progress {
	font-size: 3em;
	margin-bottom: 3rem;
	min-height: 4.5rem;
	transform: translateY(25%);
}
/* running state */
.upload--running .upload__cloud-left,
.upload--running .upload__cloud-middle,
.upload--running .upload__cloud-right {
	transition: all 0.5s ease-in-out;
}
.upload--running .upload__cloud-left {
	transform: translateX(2.5em);
}
.upload--running .upload__cloud-middle {
	transform: translate(-50%,1em) scale(1);
}
.upload--running .upload__cloud-right {
	transform: translateX(-2.5em);
}
.upload--running .upload__bubble:before {
	animation: rise var(--dur) linear forwards;
}
.upload--running .upload__progress {
	opacity: 1;
	transform: translateY(0);
	transition: all 0.3s ease-in-out;
}
/* done state */
.upload--done .upload__cloud-explode {
	animation: expand 1s 0.5s ease-in-out forwards;
	display: flex;
}
.upload--done .upload__cloud-middle {
	animation: slideUp 1.5s 0.5s ease-in-out forwards;
}
.upload--done .upload__feedback,
.upload--done .upload__feedback + .upload__button {
	animation: fadeSlideUp 0.5s 1.25s ease-in-out forwards;
}
.upload--done .upload__feedback + .upload__button {
	animation-delay: 1.4s;
}
.upload--done .upload__check-ring,
.upload--done .upload__check-line {
	animation: strokeIn 0.5s 1.25s ease-in-out forwards;
}

/* Animations */
@keyframes expand {
	from {
		transform: translate(-50%,1em) scale(0.3333); /* 23/69 */
	}
	to {
		transform: translate(-50%,37.25em) scale(1);
	}
}
@keyframes fadeSlideUp {
	to {
		opacity: 1;
		transform: translateY(0);
	}
}
@keyframes rise {
	to {
		transform: translateY(-25em);
	}
}
@keyframes strokeIn {
	to {
		stroke-dashoffset: 0;
	}
}
@keyframes slideUp {
	from {
		transform: translate(-50%,1em);
	}
	to {
		transform: translate(-50%,-23em);
	}
}

window.addEventListener("DOMContentLoaded",() => {
	const component = new FileUpload(".upload");
});

class FileUpload {
    bubbles = [];
    isUploading = false;
    progress = 0;
    timeout = null;
    uploadClass = "upload--running";
    doneClass = "upload--done";

    constructor(el) {
        this.el = document.querySelector(el);
        this.el?.addEventListener("click",this.upload.bind(this));
        this.circle = this.el?.querySelector("[data-circle]");
        this.uploadButton = this.el?.querySelector("[data-upload]");
    }
    progressDim() {
        this.uploadButton.parentElement.setAttribute("aria-hidden", "true");
    }
    progressLoop() {
        // update the progress
        this.progress += 0.01;
        this.progressUpdateDisplay();

        // spawn a bubble
        const bubble = document.createElement("div");
        const duration = Utils.randomFloat(2,3);
        const brightneess = Utils.randomFloat(0.6,1);
        const rotate = Utils.randomFloat(-15,15);
        const size = Utils.randomFloat(1,2);

        bubble.classList.add("upload__bubble");
        bubble.style.setProperty("--dur", `${duration}s`);
        bubble.style.filter = `brightness(${brightneess})`;
        bubble.style.transform = `translateX(-50%) rotate(${rotate}deg)`;
        bubble.style.width = `${size}em`;
        bubble.style.height = `${size}em`;
        this.bubbles.push(bubble);
        this.circle?.appendChild(bubble);

        // loop until finished
        if (this.progress < 1) {
            this.timeout = setTimeout(this.progressLoop.bind(this), 50);
        } else {
            this.timeout = setTimeout(this.progressDim.bind(this), 500);
            this.el.classList.add(this.doneClass);
        }
    }
    progressUpdateDisplay(clear) {
        const progress = this.el.querySelector("[data-progress]");

        if (this.circle && !clear) {
            const startSize = 13;
            const enlargeBy = 10;
            const size = startSize + enlargeBy * this.progress;

            this.circle.style.width = `${size}em`;
            this.circle.style.height = `${size}em`;
        }
        if (progress) {
            progress.innerText = clear === true ? "" :`${Math.floor(this.progress * 100)}%`;
        }
    }
    reset() {
        if (this.isUploading) {
            while (this.circle.firstChild) {
                this.circle.removeChild(this.circle.lastChild);
            }
            this.circle.removeAttribute("style");

            this.bubbles = [];
            this.el.classList.remove(this.uploadClass);
            this.el.classList.remove(this.doneClass);
            this.isUploading = false;
            this.progress = 0;
            this.progressUpdateDisplay(true);
            this.uploadButton.parentElement.setAttribute("aria-hidden", "false");
            this.uploadButton.disabled = false;
            this.uploadButton.textContent = "Upload";
        }
    }
    upload(e) {
        const { target } = e;

        if (!this.isUploading && target.hasAttribute("data-upload")) {
            this.isUploading = true;
            this.el.classList.add(this.uploadClass);

            target.disabled = true;
            target.textContent = "Uploading…";

            this.progressUpdateDisplay();
            this.timeout = setTimeout(() => {
	            if (this.circle) this.circle.style.transitionTimingFunction = "linear";

                this.progressLoop();
            }, 500);
        } else if (target.hasAttribute("data-reset")) {
            this.reset();
        }
    }
}

class Utils {
	static randomFloat(min = 0,max = 2**32) {
        const percent = crypto.getRandomValues(new Uint32Array(1))[0] / 2**32;
        const relativeValue = (max - min) * percent;

        return min + relativeValue;
    }
}