Hôm nay, mình xin chia sẻ một mẫu css trang 404 cực đẹp, chỉ dùng css thuần.

HTML.

<span class='one'>4</span>
<span class='two'>0</span>
<span class='mid'>ops!</span>
<span class='three'>4</span>

CSS.

@import url(https://fonts.googleapis.com/css?family=Fascinate);
* {
  box-sizing: border-box;
}

body, html {
  width: 100%;
  min-height: 100%;
  font-family: 'Fascinate', cursive;
  background: #6A9C92;
  font-size: 16px;
  display: -webkit-box;
  display: -webkit-flex;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-pack: center;
  -webkit-justify-content: center;
      -ms-flex-pack: center;
          justify-content: center;
  -webkit-box-orient: horizontal;
  -webkit-box-direction: normal;
  -webkit-flex-direction: row;
      -ms-flex-direction: row;
          flex-direction: row;
  overflow-y: auto;
  overflow-x: hidden;
  padding-bottom: 4rem;
}
body span, html span {
  margin: -2rem 0;
  color: #F74545;
  -webkit-align-self: center;
      -ms-flex-item-align: center;
          align-self: center;
  font-size: 34rem;
  letter-spacing: -1rem;
  -webkit-transition: font-size .3s ease;
  transition: font-size .3s ease;
  text-shadow: 0px 0px 0 #FFAC78, -1px 1px 0 #FFAC78, -2px 2px 0 #FFAC78, -3px 3px 0 #FFAC78, -4px 4px 0 #FFAC78, -5px 5px 0 #FFAC78, -6px 6px 0 #FFAC78, -7px 7px 0 #FFE2A8, -8px 8px 0 #FFE2A8, -9px 9px 0 #FFE2A8, -10px 10px 0 #FFE2A8, -11px 11px 0 #FFE2A8, -12px 12px 0 #FFE2A8, -13px 13px 0 #FFE2A8, -14px 14px 0 #FFE2A8, -15px 15px 0 #FFE2A8, -16px 16px 0 #FFE2A8, -17px 17px 0 rgba(0, 0, 0, 0.19), 0 6px 1px rgba(0, 0, 0, 0.1), 0 0 5px rgba(0, 0, 0, 0.2), 0 1px 3px rgba(0, 0, 0, 0.25), 0 3px 5px rgba(0, 0, 0, 0.28), 0 5px 10px rgba(0, 0, 0, 0.35), 0 10px 15px rgba(0, 0, 0, 0.4), 0 20px 20px rgba(0, 0, 0, 0.45);
}
body span.one, html span.one {
  -webkit-transform: rotate(-26deg);
          transform: rotate(-26deg);
}
body span.two, html span.two {
  color: #423845;
  font-size: 36rem;
}
body span.mid, html span.mid {
  color: #423845;
  font-size: 6rem;
  margin-left: -7rem;
  margin-top: 16rem;
  z-index: 3;
  letter-spacing: -6px;
}
body span.three, html span.three {
  -webkit-transform: rotate(26deg);
          transform: rotate(26deg);
  margin-left: -5rem;
  margin-top: -8rem;
}

@media (min-width: 40.6875em) and (max-width: 51.875em) {
  body span {
    font-size: 28rem;
  }
  body span.two, body span.three {
    font-size: 30rem;
  }
}
@media (min-width: 30.0625em) and (max-width: 40.625em) {
  body span {
    font-size: 22rem;
  }
  body span.two, body span.three {
    font-size: 24rem;
  }
}
@media (max-width: 30em) {
  body span {
    -webkit-align-self: center;
        -ms-flex-item-align: center;
            align-self: center;
    font-size: 18rem;
  }
  body span.two {
    font-size: 20rem;
  }
  body span.mid {
    margin-top: 11rem;
    margin-left: -5rem;
  }
  body span.three {
    margin-left: -7rem;
  }
}

Chúc các bạn thành công !