In this post, we show you page 404 beauty. This page has a black and white theme. If your website also has a black and white theme and is related to astronauts and spacecraft and the whole space, you can use this code for your 404 page. Using these ready-made codes makes website design easier for you. This code uses bootstrap.


HTML
<!-- This script got from www.devanswer.com -->
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/normalize/5.0.0/normalize.min.css">
<link rel='stylesheet' href='https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/4.1.3/css/bootstrap.min.css'>
<script src='https://cdnjs.cloudflare.com/ajax/libs/gsap/3.1.1/gsap.min.js'></script>
<div class="hamburger-menu">
    <button class="burger" data-state="closed">
        <span></span>
        <span></span>
        <span></span>
    </button>
</div>
<nav data-state="closed">
    <ul>
        <li>
            <a href="#">Home</a>
        </li>
        <li>
            <a href="#">Services</a>
        </li>
        <li>
            <a href="#">About</a>
        </li>
        <li>
            <a href="#">Contact</a>
        </li>
    </ul>
</nav>
<main>
    <div class="container">
        <div class="row">
            <div class="col-md-6 align-self-center">
                <svg version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"
                        viewBox="0 0 800 600">
                    <g>
                        <defs>
                            <clipPath id="GlassClip">
                                <path d="M380.857,346.164c-1.247,4.651-4.668,8.421-9.196,10.06c-9.332,3.377-26.2,7.817-42.301,3.5
            s-28.485-16.599-34.877-24.192c-3.101-3.684-4.177-8.66-2.93-13.311l7.453-27.798c0.756-2.82,3.181-4.868,6.088-5.13
            c6.755-0.61,20.546-0.608,41.785,5.087s33.181,12.591,38.725,16.498c2.387,1.682,3.461,4.668,2.705,7.488L380.857,346.164z" />
                            </clipPath>
                            <clipPath id="cordClip">
                                <rect width="800" height="600" />
                            </clipPath>
                        </defs>
                        <g id="planet">
                            <circle fill="none" stroke="#0E0620" stroke-width="3" stroke-miterlimit="10" cx="572.859" cy="108.803"
                                    r="90.788" />
                            <circle id="craterBig" fill="none" stroke="#0E0620" stroke-width="3" stroke-miterlimit="10" cx="548.891"
                                    cy="62.319" r="13.074" />
                            <circle id="craterSmall" fill="none" stroke="#0E0620" stroke-width="3" stroke-miterlimit="10" cx="591.743"
                                    cy="158.918" r="7.989" />
                            <path id="ring" fill="none" stroke="#0E0620" stroke-width="3" stroke-linecap="round"
                                    stroke-miterlimit="10" d="
		M476.562,101.461c-30.404,2.164-49.691,4.221-49.691,8.007c0,6.853,63.166,12.408,141.085,12.408s141.085-5.555,141.085-12.408
		c0-3.378-15.347-4.988-40.243-7.225" />
                            <path id="ringShadow" opacity="0.5" fill="none" stroke="#0E0620" stroke-width="3" stroke-linecap="round"
                                    stroke-miterlimit="10" d="
		M483.985,127.43c23.462,1.531,52.515,2.436,83.972,2.436c36.069,0,68.978-1.19,93.922-3.149" />
                        </g>
                        <g id="stars">
                            <g id="starsBig">
                                <g>
                                    <line fill="none" stroke="#0E0620" stroke-width="3" stroke-linecap="round" stroke-miterlimit="10"
                                            x1="518.07" y1="245.375" x2="518.07" y2="266.581" />
                                    <line fill="none" stroke="#0E0620" stroke-width="3" stroke-linecap="round" stroke-miterlimit="10"
                                            x1="508.129" y1="255.978" x2="528.01" y2="255.978" />
                                </g>
                                <g>
                                    <line fill="none" stroke="#0E0620" stroke-width="3" stroke-linecap="round" stroke-miterlimit="10"
                                            x1="154.55" y1="231.391" x2="154.55" y2="252.598" />
                                    <line fill="none" stroke="#0E0620" stroke-width="3" stroke-linecap="round" stroke-miterlimit="10"
                                            x1="144.609" y1="241.995" x2="164.49" y2="241.995" />
                                </g>
                                <g>
                                    <line fill="none" stroke="#0E0620" stroke-width="3" stroke-linecap="round" stroke-miterlimit="10"
                                            x1="320.135" y1="132.746" x2="320.135" y2="153.952" />
                                    <line fill="none" stroke="#0E0620" stroke-width="3" stroke-linecap="round" stroke-miterlimit="10"
                                            x1="310.194" y1="143.349" x2="330.075" y2="143.349" />
                                </g>
                                <g>
                                    <line fill="none" stroke="#0E0620" stroke-width="3" stroke-linecap="round" stroke-miterlimit="10"
                                            x1="200.67" y1="483.11" x2="200.67" y2="504.316" />
                                    <line fill="none" stroke="#0E0620" stroke-width="3" stroke-linecap="round" stroke-miterlimit="10"
                                            x1="210.611" y1="493.713" x2="190.73" y2="493.713" />
                                </g>
                            </g>
                            <g id="starsSmall">
                                <g>
                                    <line fill="none" stroke="#0E0620" stroke-width="3" stroke-linecap="round" stroke-miterlimit="10"
                                            x1="432.173" y1="380.52" x2="432.173" y2="391.83" />
                                    <line fill="none" stroke="#0E0620" stroke-width="3" stroke-linecap="round" stroke-miterlimit="10"
                                            x1="426.871" y1="386.175" x2="437.474" y2="386.175" />
                                </g>
                                <g>
                                    <line fill="none" stroke="#0E0620" stroke-width="3" stroke-linecap="round" stroke-miterlimit="10"
                                            x1="489.555" y1="299.765" x2="489.555" y2="308.124" />
                                    <line fill="none" stroke="#0E0620" stroke-width="3" stroke-linecap="round" stroke-miterlimit="10"
                                            x1="485.636" y1="303.945" x2="493.473" y2="303.945" />
                                </g>
                                <g>
                                    <line fill="none" stroke="#0E0620" stroke-width="3" stroke-linecap="round" stroke-miterlimit="10"
                                            x1="231.468" y1="291.009" x2="231.468" y2="299.369" />
                                    <line fill="none" stroke="#0E0620" stroke-width="3" stroke-linecap="round" stroke-miterlimit="10"
                                            x1="227.55" y1="295.189" x2="235.387" y2="295.189" />
                                </g>
                                <g>
                                    <line fill="none" stroke="#0E0620" stroke-width="3" stroke-linecap="round" stroke-miterlimit="10"
                                            x1="244.032" y1="547.539" x2="244.032" y2="555.898" />
                                    <line fill="none" stroke="#0E0620" stroke-width="3" stroke-linecap="round" stroke-miterlimit="10"
                                            x1="247.95" y1="551.719" x2="240.113" y2="551.719" />
                                </g>
                                <g>
                                    <line fill="none" stroke="#0E0620" stroke-width="3" stroke-linecap="round" stroke-miterlimit="10"
                                            x1="186.359" y1="406.967" x2="186.359" y2="415.326" />
                                    <line fill="none" stroke="#0E0620" stroke-width="3" stroke-linecap="round" stroke-miterlimit="10"
                                            x1="190.277" y1="411.146" x2="182.44" y2="411.146" />
                                </g>
                                <g>
                                    <line fill="none" stroke="#0E0620" stroke-width="3" stroke-linecap="round" stroke-miterlimit="10"
                                            x1="480.296" y1="406.967" x2="480.296" y2="415.326" />
                                    <line fill="none" stroke="#0E0620" stroke-width="3" stroke-linecap="round" stroke-miterlimit="10"
                                            x1="484.215" y1="411.146" x2="476.378" y2="411.146" />
                                </g>
                            </g>
                            <g id="circlesBig">
                                <circle fill="none" stroke="#0E0620" stroke-width="3" stroke-linecap="round" stroke-miterlimit="10"
                                        cx="588.977" cy="255.978" r="7.952" />
                                <circle fill="none" stroke="#0E0620" stroke-width="3" stroke-linecap="round" stroke-miterlimit="10"
                                        cx="450.066" cy="320.259" r="7.952" />
                                <circle fill="none" stroke="#0E0620" stroke-width="3" stroke-linecap="round" stroke-miterlimit="10"
                                        cx="168.303" cy="353.753" r="7.952" />
                                <circle fill="none" stroke="#0E0620" stroke-width="3" stroke-linecap="round" stroke-miterlimit="10"
                                        cx="429.522" cy="201.185" r="7.952" />
                                <circle fill="none" stroke="#0E0620" stroke-width="3" stroke-linecap="round" stroke-miterlimit="10"
                                        cx="200.67" cy="176.313" r="7.952" />
                                <circle fill="none" stroke="#0E0620" stroke-width="3" stroke-linecap="round" stroke-miterlimit="10"
                                        cx="133.343" cy="477.014" r="7.952" />
                                <circle fill="none" stroke="#0E0620" stroke-width="3" stroke-linecap="round" stroke-miterlimit="10"
                                        cx="283.521" cy="568.033" r="7.952" />
                                <circle fill="none" stroke="#0E0620" stroke-width="3" stroke-linecap="round" stroke-miterlimit="10"
                                        cx="413.618" cy="482.387" r="7.952" />
                            </g>
                            <g id="circlesSmall">
                                <circle fill="#0E0620" cx="549.879" cy="296.402" r="2.651" />
                                <circle fill="#0E0620" cx="253.29" cy="229.24" r="2.651" />
                                <circle fill="#0E0620" cx="434.824" cy="263.931" r="2.651" />
                                <circle fill="#0E0620" cx="183.708" cy="544.176" r="2.651" />
                                <circle fill="#0E0620" cx="382.515" cy="530.923" r="2.651" />
                                <circle fill="#0E0620" cx="130.693" cy="305.608" r="2.651" />
                                <circle fill="#0E0620" cx="480.296" cy="477.014" r="2.651" />
                            </g>
                        </g>
                        <g id="spaceman" clip-path="url(cordClip)">
                            <path id="cord" fill="none" stroke="#0E0620" stroke-width="3" stroke-linecap="round"
                                    stroke-linejoin="round" stroke-miterlimit="10"
                                    d="
		M273.813,410.969c0,0-54.527,39.501-115.34,38.218c-2.28-0.048-4.926-0.241-7.841-0.548
		c-68.038-7.178-134.288-43.963-167.33-103.87c-0.908-1.646-1.793-3.3-2.654-4.964c-18.395-35.511-37.259-83.385-32.075-118.817" />
                            <path id="backpack" fill="#FFFFFF" stroke="#0E0620" stroke-width="3" stroke-linecap="round"
                                    stroke-linejoin="round" stroke-miterlimit="10" d="
		M338.164,454.689l-64.726-17.353c-11.086-2.972-17.664-14.369-14.692-25.455l15.694-58.537
		c3.889-14.504,18.799-23.11,33.303-19.221l52.349,14.035c14.504,3.889,23.11,18.799,19.221,33.303l-15.694,58.537
		C360.647,451.083,349.251,457.661,338.164,454.689z" />
                            <g id="antenna">
                                <line fill="#FFFFFF" stroke="#0E0620" stroke-width="3" stroke-linecap="round" stroke-linejoin="round"
                                        stroke-miterlimit="10" x1="323.396" y1="236.625" x2="295.285" y2="353.753" />
                                <circle fill="#FFFFFF" stroke="#0E0620" stroke-width="3" stroke-linecap="round" stroke-linejoin="round"
                                        stroke-miterlimit="10" cx="323.666" cy="235.617" r="6.375" />
                            </g>
                            <g id="armR">
                                <path fill="#FFFFFF" stroke="#0E0620" stroke-width="3" stroke-linecap="round" stroke-linejoin="round"
                                        stroke-miterlimit="10" d="
			M360.633,363.039c1.352,1.061,4.91,5.056,5.824,6.634l27.874,47.634c3.855,6.649,1.59,15.164-5.059,19.02l0,0
			c-6.649,3.855-15.164,1.59-19.02-5.059l-5.603-9.663" />
                                <path fill="#FFFFFF" stroke="#0E0620" stroke-width="3" stroke-linecap="round" stroke-linejoin="round"
                                        stroke-miterlimit="10" d="
			M388.762,434.677c5.234-3.039,7.731-8.966,6.678-14.594c2.344,1.343,4.383,3.289,5.837,5.793
			c4.411,7.596,1.829,17.33-5.767,21.741c-7.596,4.411-17.33,1.829-21.741-5.767c-1.754-3.021-2.817-5.818-2.484-9.046
			C375.625,437.355,383.087,437.973,388.762,434.677z" />
                            </g>
                            <g id="armL">
                                <path fill="#FFFFFF" stroke="#0E0620" stroke-width="3" stroke-linecap="round" stroke-linejoin="round"
                                        stroke-miterlimit="10" d="
			M301.301,347.66c-1.702,0.242-5.91,1.627-7.492,2.536l-47.965,27.301c-6.664,3.829-8.963,12.335-5.134,18.999h0
			c3.829,6.664,12.335,8.963,18.999,5.134l9.685-5.564" />
                                <path fill="#FFFFFF" stroke="#0E0620" stroke-width="3" stroke-linecap="round" stroke-linejoin="round"
                                        stroke-miterlimit="10" d="
			M241.978,395.324c-3.012-5.25-2.209-11.631,1.518-15.977c-2.701-0.009-5.44,0.656-7.952,2.096
			c-7.619,4.371-10.253,14.09-5.883,21.71c4.371,7.619,14.09,10.253,21.709,5.883c3.03-1.738,5.35-3.628,6.676-6.59
			C252.013,404.214,245.243,401.017,241.978,395.324z" />
                            </g>
                            <g id="body">
                                <path fill="#FFFFFF" stroke="#0E0620" stroke-width="3" stroke-linecap="round" stroke-linejoin="round"
                                        stroke-miterlimit="10" d="
			M353.351,365.387c-7.948,1.263-16.249,0.929-24.48-1.278c-8.232-2.207-15.586-6.07-21.836-11.14
			c-17.004,4.207-31.269,17.289-36.128,35.411l-1.374,5.123c-7.112,26.525,8.617,53.791,35.13,60.899l0,0
			c26.513,7.108,53.771-8.632,60.883-35.158l1.374-5.123C371.778,395.999,365.971,377.536,353.351,365.387z" />
                                <path fill="none" stroke="#0E0620" stroke-width="3" stroke-linecap="round" stroke-linejoin="round"
                                        stroke-miterlimit="10" d="
			M269.678,394.912L269.678,394.912c26.3,20.643,59.654,29.585,93.106,25.724l2.419-0.114" />
                            </g>
                            <g id="legs">
                                <g id="legR">
                                    <path fill="#FFFFFF" stroke="#0E0620" stroke-width="3" stroke-linecap="round" stroke-linejoin="round"
                                            stroke-miterlimit="10" d="
				M312.957,456.734l-14.315,53.395c-1.896,7.07,2.299,14.338,9.37,16.234l0,0c7.07,1.896,14.338-2.299,16.234-9.37l17.838-66.534
				C333.451,455.886,323.526,457.387,312.957,456.734z" />
                                    <line fill="none" stroke="#0E0620" stroke-width="3" stroke-linecap="round" stroke-linejoin="round"
                                            stroke-miterlimit="10" x1="304.883" y1="486.849" x2="330.487" y2="493.713" />
                                </g>
                                <g id="legL">
                                    <path fill="#FFFFFF" stroke="#0E0620" stroke-width="3" stroke-linecap="round" stroke-linejoin="round"
                                            stroke-miterlimit="10" d="
				M296.315,452.273L282,505.667c-1.896,7.07-9.164,11.265-16.234,9.37l0,0c-7.07-1.896-11.265-9.164-9.37-16.234l17.838-66.534
				C278.993,441.286,286.836,447.55,296.315,452.273z" />
                                    <line fill="none" stroke="#0E0620" stroke-width="3" stroke-linecap="round" stroke-linejoin="round"
                                            stroke-miterlimit="10" x1="262.638" y1="475.522" x2="288.241" y2="482.387" />
                                </g>
                            </g>
                            <g id="head">
                                <ellipse transform="matrix(0.259 -0.9659 0.9659 0.259 -51.5445 563.2371)" fill="#FFFFFF"
                                            stroke="#0E0620" stroke-width="3" stroke-linecap="round" stroke-linejoin="round"
                                            stroke-miterlimit="10" cx="341.295" cy="315.211" rx="61.961" ry="60.305" />
                                <path id="headStripe" fill="none" stroke="#0E0620" stroke-width="3" stroke-linecap="round"
                                        stroke-linejoin="round" stroke-miterlimit="10" d="
			M330.868,261.338c-7.929,1.72-15.381,5.246-21.799,10.246" />
                                <path fill="#FFFFFF" stroke="#0E0620" stroke-width="3" stroke-linecap="round" stroke-linejoin="round"
                                        stroke-miterlimit="10" d="
			M380.857,346.164c-1.247,4.651-4.668,8.421-9.196,10.06c-9.332,3.377-26.2,7.817-42.301,3.5s-28.485-16.599-34.877-24.192
			c-3.101-3.684-4.177-8.66-2.93-13.311l7.453-27.798c0.756-2.82,3.181-4.868,6.088-5.13c6.755-0.61,20.546-0.608,41.785,5.087
			s33.181,12.591,38.725,16.498c2.387,1.682,3.461,4.668,2.705,7.488L380.857,346.164z" />
                                <g clip-path="url(#GlassClip)">
                                    <polygon id="glassShine" fill="none" stroke="#0E0620" stroke-width="3" stroke-miterlimit="10" points="
				278.436,375.599 383.003,264.076 364.393,251.618 264.807,364.928 				" />
                                </g>
                            </g>
                        </g>
                    </g>
                </svg>
            </div>
            <div class="col-md-6 align-self-center">
                <h1>404</h1>
                <h2>UH OH! You're lost.</h2>
                <p>
                    The page you are looking for does not exist.
                    How you got here is a mystery. But you can click the button below
                    to go back to the homepage.
                </p>
                <button class="btn green">HOME</button>
            </div>
        </div>
    </div>
</main>
</main><div id="bcl"><a style="font-size:8pt;text-decoration:none;" href="http://www.devanswer.com">Developers Answer</a></div>
                        

CSS
@import url("https://fonts.googleapis.com/css?family=Nunito+Sans");
:root {
	--blue: #0e0620;
	--white: #fff;
	--green: #2ccf6d;
}
html, body {
	height: 100%;
}
body {
	display: flex;
	align-items: center;
	justify-content: center;
	font-family: "Nunito Sans";
	color: var(--blue);
	font-size: 1em;
}
button {
	font-family: "Nunito Sans";
}
ul {
	list-style-type: none;
	-webkit-padding-start: 35px;
	padding-inline-start: 35px;
}
svg {
	width: 100%;
	visibility: hidden;
}
h1 {
	font-size: 7.5em;
	margin: 15px 0px;
	font-weight: bold;
}
h2 {
	font-weight: bold;
}
.hamburger-menu {
	position: absolute;
	top: 0;
	left: 0;
	padding: 35px;
	z-index: 2;
}
.hamburger-menu button {
	position: relative;
	width: 30px;
	height: 22px;
	border: none;
	background: none;
	padding: 0;
	cursor: pointer;
}
.hamburger-menu button span {
	position: absolute;
	height: 3px;
	background: #000;
	width: 100%;
	left: 0px;
	top: 0px;
	transition: 0.1s ease-in;
}
.hamburger-menu button span:nth-child(2) {
	top: 9px;
}
.hamburger-menu button span:nth-child(3) {
	top: 18px;
}
.hamburger-menu [data-state=open] span:first-child {
	transform: rotate(45deg);
	top: 10px;
}
.hamburger-menu [data-state=open] span:nth-child(2) {
	width: 0%;
	opacity: 0;
}
.hamburger-menu [data-state=open] span:nth-child(3) {
	transform: rotate(-45deg);
	top: 10px;
}
nav {
	position: absolute;
	height: 100%;
	top: 0;
	left: 0;
	background: var(--green);
	color: var(--blue);
	width: 300px;
	z-index: 1;
	padding-top: 80px;
	transform: translateX(-100%);
	transition: 0.24s cubic-bezier(0.52, 0.01, 0.8, 1);
}
nav li {
	transform: translateX(-5px);
	transition: 0.16s cubic-bezier(0.44, 0.09, 0.46, 0.84);
	opacity: 0;
}
nav a {
	display: block;
	font-size: 1.75em;
	font-weight: bold;
	text-decoration: none;
	color: inherit;
	transition: 0.24s ease-in-out;
}
nav a:hover {
	text-decoration: none;
	color: var(--white);
}
nav[data-state=open] {
	transform: translateX(0%);
}
nav[data-state=open] ul li:nth-child(1) {
	transition-delay: 0.16s;
	transform: translateX(0px);
	opacity: 1;
}
nav[data-state=open] ul li:nth-child(2) {
	transition-delay: 0.32s;
	transform: translateX(0px);
	opacity: 1;
}
nav[data-state=open] ul li:nth-child(3) {
	transition-delay: 0.48s;
	transform: translateX(0px);
	opacity: 1;
}
nav[data-state=open] ul li:nth-child(4) {
	transition-delay: 0.64s;
	transform: translateX(0px);
	opacity: 1;
}
.btn {
	z-index: 1;
	overflow: hidden;
	background: transparent;
	position: relative;
	padding: 8px 50px;
	border-radius: 30px;
	cursor: pointer;
	font-size: 1em;
	letter-spacing: 2px;
	transition: 0.2s ease;
	font-weight: bold;
	margin: 5px 0px;
}
.btn.green {
	border: 4px solid var(--green);
	color: var(--blue);
}
.btn.green:before {
	content: "";
	position: absolute;
	left: 0;
	top: 0;
	width: 0%;
	height: 100%;
	background: var(--green);
	z-index: -1;
	transition: 0.2s ease;
}
.btn.green:hover {
	color: var(--white);
	background: var(--green);
	transition: 0.2s ease;
}
.btn.green:hover:before {
	width: 100%;
}
@media screen and (max-width: 768px) {
	body {
		display: block;
	}
	.container {
		margin-top: 70px;
		margin-bottom: 70px;
	}
}
Javascript
gsap.set("svg", { visibility: "visible" });
gsap.to("#headStripe", {
    y: 0.5,
    rotation: 1,
    yoyo: true,
    repeat: -1,
    ease: "sine.inOut",
    duration: 1
});
gsap.to("#spaceman", {
    y: 0.5,
    rotation: 1,
    yoyo: true,
    repeat: -1,
    ease: "sine.inOut",
    duration: 1
});
gsap.to("#craterSmall", {
    x: -3,
    yoyo: true,
    repeat: -1,
    duration: 1,
    ease: "sine.inOut"
});
gsap.to("#craterBig", {
    x: 3,
    yoyo: true,
    repeat: -1,
    duration: 1,
    ease: "sine.inOut"
});
gsap.to("#planet", {
    rotation: -2,
    yoyo: true,
    repeat: -1,
    duration: 1,
    ease: "sine.inOut",
    transformOrigin: "50% 50%"
});
gsap.to("#starsBig g", {
    rotation: "random(-30,30)",
    transformOrigin: "50% 50%",
    yoyo: true,
    repeat: -1,
    ease: "sine.inOut"
});
gsap.fromTo(
    "#starsSmall g",
    { scale: 0, transformOrigin: "50% 50%" },
    { scale: 1, transformOrigin: "50% 50%", yoyo: true, repeat: -1, stagger: 0.1 });
gsap.to("#circlesSmall circle", {
    y: -4,
    yoyo: true,
    duration: 1,
    ease: "sine.inOut",
    repeat: -1
});
gsap.to("#circlesBig circle", {
    y: -2,
    yoyo: true,
    duration: 1,
    ease: "sine.inOut",
    repeat: -1
});
gsap.set("#glassShine", { x: -68 });
gsap.to("#glassShine", {
    x: 80,
    duration: 2,
    rotation: -30,
    ease: "expo.inOut",
    transformOrigin: "50% 50%",
    repeat: -1,
    repeatDelay: 8,
    delay: 2
});
const burger = document.querySelector('.burger');
const nav = document.querySelector('nav');
burger.addEventListener('click', e => {
    burger.dataset.state === 'closed' ? burger.dataset.state = "open" : burger.dataset.state = "closed";
    nav.dataset.state === "closed" ? nav.dataset.state = "open" : nav.dataset.state = "closed";
});