demo.css

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: 'Roboto', sans-serif;
  font-size: 1rem;
  background-color: #1d1d22;
  letter-spacing: 1px;
}

.container-form {
  position: relative;
  overflow: hidden;
  height: auto;
  width: 98vw;
  max-width: 800px;
  margin: 10px auto;
  display: flex;
  background-color: #0b101a;
  border: 1px solid rgb(108, 117, 125);
  border-radius: 5px;
  box-shadow: 0 0 20px rgba(255, 255, 255, 0.4);
}

form {
  width: 100%;
  min-width: 200px;
  padding: 15px 20px;
  color: #fdfeff;
  justify-content: center;
  flex-grow: 1;
}

form h1 {
  font-size: 2em;
  font-weight: 300;
  text-align: center;
  color: #2196f3;
  padding-top: 0;
  margin-top: 0;
}

input,
select,
textarea {
  border: 1px solid #c6c6c6;
  border-radius: 5px;
  text-align: left;
  width: 100%;
}

.group {
  position: relative;
  margin: 35px 15px;
}

.group input:not([type="checkbox"]),
.group select {
  background-color: transparent;
  color: #c6c6c6;
  font-size: 1em;
  padding: 10px;
  padding-left: 5px;
  display: block;
  border: none;
  border: 0;
  outline: 0;
  border-radius: 0;
  border-bottom: 1px solid rgba(108, 117, 125, 0.4);
}

/* Select only webkit browsers */
@media screen and (-webkit-min-device-pixel-ratio:0) {
  select {
    appearance: none;
    padding-right: 15px;
    background-image: url('data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" width="20" height="15" viewBox="0 0 15 15" fill="%23FFF"><path d="M 8,5.5 11,9.5 14,5.5 z"></path></svg>');
    background-repeat: no-repeat;
    background-position: center right;
  }
}

.group select option {
  color: #c5e4f9;
  background-color: #22232a;
}

.group input:focus,
.group select:focus {
  outline: none !important;
}

.group input:focus~.bar:before,
.group select:focus~.bar:before {
  width: 100%;
}

.group label {
  position: absolute;
  top: -14px;
  left: 5px;
  font-size: 12px;
  color: #2196f3;
  font-weight: normal;
  pointer-events: none;
}

.group.inline {
  margin: 15px;
  display: flex;
  justify-content: flex-start;
  align-items: center;
  border-bottom: 1px solid rgba(108, 117, 125, 0.4);
  padding: 10px 0;
}

.group.inline label {
  position: relative;
  top: 0;
  font-size: 14px;
  margin-left: 8px;
  pointer-events: all;
}

.wrapper-checkbox {
  width: 30px !important;
}

.custom-checkbox {
  position: relative;
  font-size: 1em;
  height: 30px;
  width: 30px;
  padding: 0;
  appearance: none;
  border: 1px solid rgba(70, 96, 120, 0.9) !important;
  border-radius: 6px !important;
  background: transparent;
}

.custom-checkbox:checked:before,
.custom-checkbox:checked:after {
  content: "\2714";
  position: absolute;
  display: flex;
  justify-content: center;
  align-items: center;
  top: 0;
  left: 0;
  font-size: 1.4em;
  height: 100%;
  width: 100%;
  color: #2196f3;
}

.group .bar {
  position: relative;
  display: block;
}

.group .bar:before {
  content: '';
  height: 2px;
  width: 0;
  bottom: 0px;
  position: absolute;
  background-color: #2196f3;
  transition: 300ms ease all;
  left: 0%;
}

.btn-box {
  text-align: center;
  margin: 10px;
}

.btn {
  cursor: pointer;
  background-color: #0875ce;
  color: #deeffd;
  border: 0;
  padding: 18px 30px;
  font-size: 1.1em;
  border-radius: 3px;
  letter-spacing: 0.06em;
  text-decoration: none;
  outline: none;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.12), 0 1px 2px rgba(0, 0, 0, 0.24);
  user-select: none;
}

.btn:hover {
  background-color: #2196f3;
  color: #fff;
}

.ripple {
  position: relative;
  overflow: hidden;
  transform: translate3d(0, 0, 0);
}

.ripple:after {
  content: '';
  display: block;
  position: absolute;
  width: 100%;
  height: 100%;
  top: 0;
  left: 0;
  pointer-events: none;
  background-image: radial-gradient(circle, #fff 10%, transparent 10.01%);
  background-repeat: no-repeat;
  background-position: 50%;
  transform: scale(10, 10);
  opacity: 0;
  transition: transform 0.5s, opacity 1s;
}

.ripple:active:after {
  transform: scale(0, 0);
  opacity: 0.3;
  transition: 0s;
}


/* examples insert html*/
.wrapper-notification {
  display: flex;
  justify-content: flex-start;
  align-items: center;
  gap: 10px;
  height: 100%;
  letter-spacing: 2px;
}

.icons {
  display: flex;
  justify-content: center;
  align-items: center;
  width: 70px;
  height: 70px;
  background-repeat: no-repeat;
  background-position: center;
  background-size: contain;
}

.icons.icon-info {
  background-image: url('demo_img/info.png');
}

.icons.icon-warning {
  background-image: url('demo_img/warning.png');
}

.icons.icon-success {
  background-image: url('demo_img/success.png');
}

.icons.icon-error {
  background-image: url('demo_img/404-error.png');
  width: 100px;
}

.icons.small {
  width: 24px;
  height: 24px;
}

.icons.medium {
  width: 38px;
  height: 38px;
}

.icons.small.icon-send {
  background-image: url('demo_img/send.png');
}

.wrapper-notification .title-cust {
  color: #fff;
  font-size: 1.1em;
  font-weight: 600;
}

.wrapper-notification .title-error {
  -webkit-text-stroke: 1px red;
  -webkit-text-fill-color: transparent;
}

.wrapper-notification .title-info {
  -webkit-text-stroke: 1px #084981;
  -webkit-text-fill-color: transparent;
}

.wrapper-notification .title-warning {
  -webkit-text-stroke: 1px #ff4500;
  -webkit-text-fill-color: transparent;
}

.wrapper-notification .title-success {
  -webkit-text-stroke: 1px #037a4a;
  -webkit-text-fill-color: transparent;
}

.wrapper-notification .title-dialog {
  color: #02659b;
  font-size: 1em;
  font-weight: 600;
}

.wrapper-notification .message {
  flex: 1;
}

.wrapper-notification .message-text-error {
  color: rgb(66, 67, 67);
  font-weight: 500;
}

.label-message {
  margin-bottom: 5px;
  color: #033e5e;
}

.asterisk {
  color: #fa6868;
  margin-left: 4px;
}

textarea.popup-textarea {
  font-weight: 500;
  font-size: 0.9em;
  color: #777;
  outline: none;
  border: 1px solid rgba(3, 62, 94, 0.15);
  background: #f4f4f4;
  border-radius: 5px;
  padding: 0.6em;
  width: 100%;
  max-height: 150px;
  resize: vertical;
}

.popup-textarea::placeholder {
  color: rgb(136, 136, 136, 0.7);
  font-size: 0.88em;
}

.popup-textarea.invalid {
  animation: pulse-border 400ms 1;
}

.popup-textarea.invalid::placeholder {
  color: rgb(255, 0, 0);
}

@keyframes pulse-border {
  0% {
    border-color: rgba(3, 62, 94, 0.15);
    background: #f4f4f4;
  }

  50% {
    border-color: rgba(255, 0, 0, 0.7);
    background-color: rgb(255, 240, 240, 0.7);
  }

  100% {
    border-color: rgba(3, 62, 94, 0.15);
    background: #f4f4f4;
  }
}