Why do you use simple or default 404 page? You can easily made a beautiful one. The following code is a night and moon template for “404 not found” page. It doesn’t use any images and everything was created just by code! Therefore, it is simple and responsive. Enjoy!


HTML
<!-- This script got from www.devanswer.com -->
<div class="background">
<div class="ground"></div>
</div>
<div class="container">
<div class="left-section">
<div class="inner-content">
<h1 class="heading">404</h1>
<p class="subheading">Looks like the page you were looking for is no longer here.</p>
</div>
</div>
<div class="right-section">
<svg class="svgimg" xmlns="http://www.w3.org/2000/svg" viewBox="51.5 -15.288 385 505.565">
<g class="bench-legs">
<path d="M202.778,391.666h11.111v98.611h-11.111V391.666z M370.833,390.277h11.111v100h-11.111V390.277z M183.333,456.944h11.111
          v33.333h-11.111V456.944z M393.056,456.944h11.111v33.333h-11.111V456.944z" />
</g>
<g class="top-bench">
<path d="M396.527,397.917c0,1.534-1.243,2.777-2.777,2.777H190.972c-1.534,0-2.778-1.243-2.778-2.777v-8.333
          c0-1.535,1.244-2.778,2.778-2.778H393.75c1.534,0,2.777,1.243,2.777,2.778V397.917z M400.694,414.583
          c0,1.534-1.243,2.778-2.777,2.778H188.194c-1.534,0-2.778-1.244-2.778-2.778v-8.333c0-1.534,1.244-2.777,2.778-2.777h209.723
          c1.534,0,2.777,1.243,2.777,2.777V414.583z M403.473,431.25c0,1.534-1.244,2.777-2.778,2.777H184.028
          c-1.534,0-2.778-1.243-2.778-2.777v-8.333c0-1.534,1.244-2.778,2.778-2.778h216.667c1.534,0,2.778,1.244,2.778,2.778V431.25z" />
</g>
<g class="bottom-bench">
<path d="M417.361,459.027c0,0.769-1.244,1.39-2.778,1.39H170.139c-1.533,0-2.777-0.621-2.777-1.39v-4.86
          c0-0.769,1.244-0.694,2.777-0.694h244.444c1.534,0,2.778-0.074,2.778,0.694V459.027z" />
<path d="M185.417,443.75H400c0,0,18.143,9.721,17.361,10.417l-250-0.696C167.303,451.65,185.417,443.75,185.417,443.75z" />
</g>
<g id="lamp">
<path class="lamp-details" d="M125.694,421.997c0,1.257-0.73,3.697-1.633,3.697H113.44c-0.903,0-1.633-2.44-1.633-3.697V84.917
          c0-1.257,0.73-2.278,1.633-2.278h10.621c0.903,0,1.633,1.02,1.633,2.278V421.997z" />
<path class="lamp-accent" d="M128.472,93.75c0,1.534-1.244,2.778-2.778,2.778h-13.889c-1.534,0-2.778-1.244-2.778-2.778V79.861
          c0-1.534,1.244-2.778,2.778-2.778h13.889c1.534,0,2.778,1.244,2.778,2.778V93.75z" />
<circle class="lamp-light" cx="119.676" cy="44.22" r="40.51" />
<path class="lamp-details" d="M149.306,71.528c0,3.242-13.37,13.889-29.861,13.889S89.583,75.232,89.583,71.528c0-4.166,13.369-13.889,29.861-13.889
          S149.306,67.362,149.306,71.528z" />
<radialGradient class="light-gradient" id="SVGID_1_" cx="119.676" cy="44.22" r="65" gradientUnits="userSpaceOnUse">
<stop offset="0%" style="stop-color:#FFFFFF; stop-opacity: 1" />
<stop offset="50%" style="stop-color:#EDEDED; stop-opacity: 0.5">
<animate attributeName="stop-opacity" values="0.0; 0.5; 0.0" dur="5000ms" repeatCount="indefinite"></animate>
</stop>
<stop offset="100%" style="stop-color:#EDEDED; stop-opacity: 0" />
</radialGradient>
<circle class="lamp-light__glow" fill="url(#SVGID_1_)" cx="119.676" cy="44.22" r="65" />
<path class="lamp-bottom" d="M135.417,487.781c0,1.378-1.244,2.496-2.778,2.496H106.25c-1.534,0-2.778-1.118-2.778-2.496v-74.869
          c0-1.378,1.244-2.495,2.778-2.495h26.389c1.534,0,2.778,1.117,2.778,2.495V487.781z" />
</g>
</svg>
</div>
</div><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=Fira+Sans");
/*Variables */
.left-section .inner-content {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
}

* {
  box-sizing: border-box;
}

html, body {
  margin: 0;
  padding: 0;
}

body {
  font-family: "Fira Sans", sans-serif;
  color: #f5f6fa;
}

.background {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: linear-gradient(#0C0E10, #446182);
}
.background .ground {
  position: absolute;
  bottom: 0;
  width: 100%;
  height: 25vh;
  background: #0C0E10;
}
@media (max-width: 770px) {
  .background .ground {
    height: 0vh;
  }
}

.container {
  position: relative;
  margin: 0 auto;
  width: 85%;
  height: 100vh;
  padding-bottom: 25vh;
  display: flex;
  flex-direction: row;
  justify-content: space-around;
}
@media (max-width: 770px) {
  .container {
    flex-direction: column;
    padding-bottom: 0vh;
  }
}

.left-section, .right-section {
  position: relative;
}

.left-section {
  width: 40%;
}
@media (max-width: 770px) {
  .left-section {
    width: 100%;
    height: 40%;
    position: absolute;
    top: 0;
  }
}
@media (max-width: 770px) {
  .left-section .inner-content {
    position: relative;
    padding: 1rem 0;
  }
}

.heading {
  text-align: center;
  font-size: 9em;
  line-height: 1.3em;
  margin: 2rem 0 0.5rem 0;
  padding: 0;
  text-shadow: 0 0 1rem #fefefe;
}
@media (max-width: 770px) {
  .heading {
    font-size: 7em;
    line-height: 1.15;
    margin: 0;
  }
}

.subheading {
  text-align: center;
  max-width: 480px;
  font-size: 1.5em;
  line-height: 1.15em;
  padding: 0 1rem;
  margin: 0 auto;
}
@media (max-width: 770px) {
  .subheading {
    font-size: 1.3em;
    line-height: 1.15;
    max-width: 100%;
  }
}

.right-section {
  width: 50%;
}
@media (max-width: 770px) {
  .right-section {
    width: 100%;
    height: 60%;
    position: absolute;
    bottom: 0;
  }
}

.svgimg {
  position: absolute;
  bottom: 0;
  padding-top: 10vh;
  padding-left: 1vh;
  max-width: 100%;
  max-height: 100%;
}
@media (max-width: 770px) {
  .svgimg {
    padding: 0;
  }
}
.svgimg .bench-legs {
  fill: #0C0E10;
}
.svgimg .top-bench, .svgimg .bottom-bench {
  stroke: #0C0E10;
  stroke-width: 1px;
  fill: #5B3E2B;
}
.svgimg .bottom-bench path:nth-child(1) {
  fill: #432d20;
}
.svgimg .lamp-details {
  fill: #202425;
}
.svgimg .lamp-accent {
  fill: #2c3133;
}
.svgimg .lamp-bottom {
  fill: linear-gradient(#202425, #0C0E10);
}
.svgimg .lamp-light {
  fill: #EFEFEF;
}

@keyframes glow {
  0% {
    text-shadow: 0 0 1rem #fefefe;
  }
  50% {
    text-shadow: 0 0 1.85rem #ededed;
  }
  100% {
    text-shadow: 0 0 1rem #fefefe;
  }
}