Animacion Input

by Slee

HTML

<!doctype html>
<html lang="es">
  <head>
    <meta charset="UTF-8" />
    <meta
      name="viewport"
      content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0"
    />
    <title>Animaciòn a un Input con Html y Css | SLee Dw</title>
    <link rel="stylesheet" href="estilos.css" />
  </head>
  <body>
    <form class="form">
      <input type="text" required />
      <label class="lbl-nombre">
        <span class="text-nomb">Nombre</span>
      </label>
    </form>
  </body>
</html>

CSS

@import url("https://fonts.googleapis.com/css?family=Open+Sans&display=swap");
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: "Open Sans", sans-serif;
}
body {
  width: 100%;
  height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  background: #0b1721;
}
.form {
  width: 100%;
  height: 50px;
  max-width: 400px;
  position: relative;
  overflow: hidden;
}
.form input {
  width: 100%;
  height: 100%;
  background: none;
  color: #fff;
  padding-top: 20px;
  border: none;
  outline: 0px;
}
.form .lbl-nombre {
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  border-bottom: 1px solid #c7c7c7;
}
.form .lbl-nombre:after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -1px;
  width: 100%;
  height: 100%;
  border-bottom: 3px solid #2ecece;
  transform: translateX(-100%);
  transition: all 0.3s ease;
}
.text-nomb {
  position: absolute;
  bottom: 5px;
  left: 0;
  transition: all 0.3s ease;
  color: #fff;
}
.form input:focus + .lbl-nombre .text-nomb,
.form input:valid + .lbl-nombre .text-nomb {
  transform: translateY(-150%);
  font-size: 14px;
  color: #2ecece;
}
.form input:focus + .lbl-nombre:after,
.form input:valid + .lbl-nombre:after {
  transform: translateX(0%);
}
@media only screen and (min-width: 320px) and (max-width: 768px) {
  .form {
    width: 85%;
  }
}