404.css

@import url('https://fonts.googleapis.com/css2?family=Hind+Siliguri:wght@300;400;500;600;700&family=Poppins:ital,wght@0,100;0,200;0,300;0,400;0,500;0,600;0,700;0,800;0,900;1,100;1,200;1,300;1,400;1,500;1,600;1,700;1,800;1,900&display=swap');

.bd-placeholder-img {
  font-size: 1.125rem;
  text-anchor: middle;
  -webkit-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;
}

@media (min-width: 768px) {
  .bd-placeholder-img-lg {
    font-size: 3.5rem;
  }

}

a,
a:focus,
a:hover {
  color: #fff;
  text-decoration: none
}

.btn-secondary,
.btn-secondary:hover,
.btn-secondary:focus {
  color: #333;
  text-shadow: none;
  /* Prevent inheritance from `body` */
  background-color: #fff;
  border: .05rem solid #fff;
}

html,
body {
  height: 100%;
  background: #161616;
  font-family: Poppins, sans-serif;
  background-image: linear-gradient(to right bottom, #080034, #0b012c, #0c0224, #0b031d, #080415, #080513, #090711, #09080e, #0c0a13, #0e0d17, #0f0f1b, #10111f);
}

body {
  display: -ms-flexbox;
  display: flex;
  color: #fff;
  text-shadow: 0 .05rem .1rem rgba(0, 0, 0, .5);
  box-shadow: inset 0 0 5rem rgba(0, 0, 0, .5);
}

.cover-container {
  max-width: 42em;
}

.masthead {
  margin-bottom: 2rem;
}

.masthead-brand {
  margin-bottom: 0;
}

.nav-masthead .nav-link {
  padding: .25rem 0;
  font-weight: 400;
  color: rgba(255, 255, 255, .5);
  background-color: transparent;
  border-bottom: .25rem solid transparent;
}

.nav-masthead .nav-link:hover,
.nav-masthead .nav-link:focus {
  border-bottom-color: rgba(255, 255, 255, .25);
}

.nav-masthead .nav-link+.nav-link {
  margin-left: 1rem;
}

.nav-masthead .active {
  color: #fff;
  border-bottom-color: #fff;
}

@media (min-width: 48em) {
  .masthead-brand {
    float: left;
  }

  .nav-masthead {
    float: right;
  }

}

.lead {
  font-size: 1.4rem;
  font-family: 'Hind Siliguri';
}

@media screen and (max-width: 600px) {
  #headbrand {
    visibility: hidden;
    clear: both;
    display: none;
  }
}

.cover {
  padding: 0 1.5rem;
}

.cover {
  padding: .75rem 1.25rem;
  font-weight: 700;
}

.mastfoot {
  color: #5a5a5a;
  font-size: 0.8rem;
}

.btn-lg {
  background-color: #272a5c;
  padding: .60rem 1rem;
  border: none;
  color: #c9e1fc;
  font-weight: 400;
  font-size: 0.8rem;
  border-radius: 60px;
  transition: ease-in-out 200ms;
}

.btn-lg:hover {
  background-color: #5b63db;
  border: none;
  color: #021e35;
  font-weight: 700;
  font-size: 0.9rem;
  border-radius: 30px;
  transition: ease 400ms;
}

#sonoth {
  color: #b6b6b6;
  transition: ease-in-out 200ms;
}

#sonoth:hover {
  color: #e4e4e4;
  transition: ease 200ms;
  font-size: 1rem;
}


#signup {
  color: #fdfdfd;
}

.cover-heading {
  font-size: 2.6rem;
  text-shadow: 0px 0px 20px #5b63db;
}


* {
  -webkit-user-select: none;
  /* Safari */
  -ms-user-select: none;
  /* IE 10 and IE 11 */
  user-select: none;
  /* Standard syntax */
}

#header-brand-logo {
  width: 20px;
  height: 20px;
  margin: 0px 10px 4px 0;
}