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CSS

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JavaScript

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HTML 

              
                <div id="clock"></div>
!

CSS 

              
                body {
	background: #2B55DD;
}
#clock {
	position: absolute;
	top: 50%;
	left: 50%;
	transform: translate(-50%, -50%);
	width: calc(100vw - 4px);
	height: auto;
	max-width: 300px;
}
!

JS 

              
                function initClock(elt, opt_properties) {
	const defaultProperties = {color: '#0ff', date: new Date(), glow: true, militaryTime: false, showMs: true};
	const c = Object.assign(defaultProperties, opt_properties);
	!c.dotColor ? c.dotColor = defaultProperties.color : false;
	const getSecondsPassed = (now = c.date, militaryTime = c.militaryTime) => {
		const s10 = Math.floor(now.getSeconds());
		const m10 = Math.floor(now.getMinutes() * 60 + s10);
		const h = Math.floor(now.getHours() * 3600 + m10);
		return { hour: h, minute10: m10, minute1: Math.floor((now.getMinutes() % 10) * 60 + s10), second10: s10, second1: Math.floor(now.getSeconds() % 10) };
	};
	let td = getSecondsPassed();
	let vxEnd = c.showMs ? 175 : 130;
	let showGlow = c.glow ? `<use href="#fullClock" filter="url(#glow)"/>` : '';
	let showGlowBlur = c.glow ? `<filter id="glow" x="-200%" y="-200%" width="1000%" height="1000%"><feGaussianBlur in="SourceGraphic" stdDeviation="1.4" /></filter>` : '';
	let hrDur = c.militaryTime ? '86400' : '43200';
	let hr1Offsets = c.militaryTime ? `0 0; 0 -30; 0 -60; 0 -90; 0 -120; 0 -150; 0 -180; 0 -210; 0 -240; 0 -270; 0 0; 0 -30; 0 -60; 0 -90; 0 -120; 0 -150; 0 -180; 0 -210; 0 -240; 0 -270; 0 0; 0 -30; 0 -60; 0 -90` : `0 -60; 0 -30; 0 -60; 0 -90; 0 -120; 0 -150; 0 -180; 0 -210; 0 -240; 0 -270; 0 0; 0 -30`;
	let hr10Offsets = c.militaryTime ? `0 0; 0 0; 0 0; 0 0; 0 0; 0 0; 0 0; 0 0; 0 0; 0 0; 0 -30; 0 -30; 0 -30; 0 -30; 0 -30; 0 -30; 0 -30; 0 -30; 0 -30; 0 -30; 0 -60; 0 -60; 0 -60; 0 -60` : `0 -30; 0 0; 0 0; 0 0; 0 0; 0 0; 0 0; 0 0; 0 0; 0 0; 0 -30; 0 -30`;
	let msDots = c.showMs ? `M 132.5 10 v0 m0 10 v0` : '';
	let milliseconds = c.showMs ? `<g class="ms10"><use href="#nums" transform="translate(135)" /><animateTransform id="ms10" attributeName="transform" type="translate" values="0 0; 0 -30; 0 -60; 0 -90; 0 -120; 0 -150; 0 -180; 0 -210; 0 -240; 0 -270" dur="1s" begin="0s" repeatCount="indefinite" calcMode="discrete" /></g><g class="ms"><use href="#nums" transform="translate(155)" /><animateTransform id="ms" attributeName="transform" type="translate" values="0 0; 0 -30; 0 -60; 0 -90; 0 -120; 0 -150; 0 -180; 0 -210; 0 -240; 0 -270" dur=".1s" begin="0s" repeatCount="indefinite" calcMode="discrete" /></g>`	: '';
	let svg = `<svg id="clockItToMe" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 ${vxEnd} 30"><defs>${showGlowBlur}<marker id="v" viewBox="0 0 10 10" refX="5" refY="2" markerWidth="8" markerHeight="8" orient="auto"><path d="M 0 2 l 2 -2 h 6 l 2 2 l -2 2 l -6 0 z" fill="${c.color}" /></marker><marker id="h" viewBox="0 0 10 10" refX="5" refY="8" markerWidth="8" markerHeight="8" orient="rotate(90deg)"><path d="M 0 2 l 2 -2 h 6 l 2 2 l -2 2 l -6 0 z" fill="${c.color}" /></marker><g id="nums" stroke="none" fill="none"><path d="M5 0v 10 10 60 50 30 30 10 50 10 20 30" marker-mid="url(#v)" /><path d="M10 0v10 20 40 10 10 10 10 10 20 20 10 10 10 10 10 10 30 10 10 10 10 10 10" marker-mid="url(#h)" /><path d="M15 0v10 10 20 10 20 30 10 20 10 30 30 20 10 20 10 20 10 20" marker-mid="url(#v)" /></g></defs><g id="fullClock"><g class="hr10"><use href="#nums" /><animateTransform id="hr10" attributeName="transform" type="translate" values="${hr10Offsets}" dur="${hrDur}s" begin="-${td.hour}s" repeatCount="indefinite" calcMode="discrete" /></g><g class="hr"><use href="#nums" transform="translate(20)" /><animateTransform id="hr" attributeName="transform" type="translate" values="${hr1Offsets}" dur="${hrDur}s" begin="-${td.hour}s" repeatCount="indefinite" calcMode="discrete" /></g><g class="min10"><use href="#nums" transform="translate(45)" /><animateTransform id="min10" attributeName="transform" type="translate" values="0 0; 0 -30; 0 -60; 0 -90; 0 -120; 0 -150" dur="3600s" begin="-${td.minute10}s" repeatCount="indefinite" calcMode="discrete" /></g><g class="min"><use href="#nums" transform="translate(65)" /><animateTransform id="min" attributeName="transform" type="translate" values="0 0; 0 -30; 0 -60; 0 -90; 0 -120; 0 -150; 0 -180; 0 -210; 0 -240; 0 -270" dur="600s" begin="-${td.minute1}s" repeatCount="indefinite" calcMode="discrete" /></g><g class="sec10"><use href="#nums" transform="translate(90)" /><animateTransform id="sec10" attributeName="transform" type="translate" values="0 0; 0 -30; 0 -60; 0 -90; 0 -120; 0 -150" dur="60s" begin="-${td.second10}s" repeatCount="indefinite" calcMode="discrete" /></g><g class="sec"><use href="#nums" transform="translate(110)" /><animateTransform id="sec" attributeName="transform" type="translate" values="0 0; 0 -30; 0 -60; 0 -90; 0 -120; 0 -150; 0 -180; 0 -210; 0 -240; 0 -270" dur="10s" begin="-${td.second1}s" repeatCount="indefinite" calcMode="discrete" /></g>${milliseconds}<path d="M42.5 10 v0 m0 10 v0 M 87.5 10 v0 m0 10 v0${msDots}" stroke="${c.dotColor}" stroke-width="3" stroke-linecap="square" /></g>${showGlow}</svg>`;
	const wrapper = document.createElement("div");
	wrapper.insertAdjacentHTML('afterbegin', svg);
	const doc = wrapper.firstChild;
	elt.appendChild(doc);
}
initClock(document.querySelector("#clock"), {color: '#D5FF77', dotColor: '#80AACC', showMs: true});
// refresh it if we leave the page
document.addEventListener("visibilitychange", () => {
  if (!document.hidden) {
		clock.innerHTML = '';
    initClock(document.querySelector("#clock"), {color: '#D5FF77', dotColor: '#80AACC', showMs: true});
  }
});
!
999px

Console