html {
  background-color: black;
  color: white;
  font-family: helvetica;
}

h1 { font-size: 45px; }
h2 { font-size: 30px; }
h1,h2 { font-family: times; }

.block {
  background-color: #152a20;
  margin: 1.5%;
  padding: 1.5%;
  border-radius: 7px;
}
.text {
  font-family: 'Times New Roman', Times, serif;
  font-size: 20px;
  color: white;
  background-color: black;
  border: 2px solid white;
}

.clearfix::after {
  content: "";
  clear: both;
  display: table;
}
.justify-centre {
  justify-content: center;
  text-align: center;
}
.centre-div {
  margin: auto;
}

.disabled {
  background: #253a30;
}
.disabled:hover {
  background: #454a48;
}
.enabled {
  background: #158a60;
}
.enabled:hover {
  background: #1ba368;
}

a {
  color: #f80;
}

span {
  display: inline-block;
}

img {
  width: 100%;
  display: block;
  margin-left: auto;
  margin-right: auto;
}

.slider {
  -webkit-appearance: none;
  -moz-appearance: none;
  appearance: none;
  width: 256px;
  height: 15px;
  background: #253a30;
  outline: none;
  transition: background .2s; 
  cursor: pointer;
  border-radius: 5px;
}
.slider::-webkit-slider-thumb,.slider::-moz-range-thumb {
  -webkit-appearance: none;
  -moz-appearance: none;
  appearance: none;
  width: 25px;
  height: 25px;
  background: #158a60;
  cursor: pointer;
  outline: none;
}
.slider:hover {
  background: #454a48;
}

header {
  font-size: 70px;
  font-style: bold;
  color: #cfd;
}
subheader {
  font-size: 20px;
  color: #2e8;
}

button {
  color: white;
  cursor: pointer;
  font-weight: bold;
  height: 60px;
  border-radius: 60px;
  transition: border-radius .2s, background-color .25s, transform .05s;
  transition-timing-function: ease-in-out;
  border-width: 0;
  background-color: #0b0;
  font-size: 20px;
  padding: 20px;
}
button:hover {
  border-radius: 5px;
  background-color: #080;
}
button:active {
  transform: translate(0px, 2px);
}
.red {
  background-color: red;
}
.red:hover {
  background-color: #c00;
}
.blue {
  background-color: blue;
}
.blue:hover {
  background-color: #00c;
}