输入字段的渐变颜色

Question

我认为只是一个相对简单的问题，但找不到要更改的内容。我单击此输入字段，您会在字段底部获得渐变颜色。我需要添加一些东西以在页面加载时（因此未单击）底部获得红色渐变颜色，当单击时渐变变为黄色到粉红色渐变。提前致谢！

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

body, html {
	height: 100%;
	font-family: Poppins-Regular, sans-serif;
}

/*---------------------------------------------*/
a {
	font-family: Poppins-Regular;
	font-size: 14px;
	line-height: 1.7;
	color: #666666;
	margin: 0px;
	transition: all 0.4s;
	-webkit-transition: all 0.4s;
  -o-transition: all 0.4s;
  -moz-transition: all 0.4s;
}

a:focus {
	outline: none !important;
}

a:hover {
	text-decoration: none;
  color: #6a7dfe;
  color: -webkit-linear-gradient(left, #21d4fd, #b721ff);
  color: -o-linear-gradient(left, #21d4fd, #b721ff);
  color: -moz-linear-gradient(left, #21d4fd, #b721ff);
  color: linear-gradient(left, #21d4fd, #b721ff);
}

/*---------------------------------------------*/
h1,h2,h3,h4,h5,h6 {
	margin: 0px;
}

p {
	font-family: Poppins-Regular;
	font-size: 14px;
	line-height: 1.7;
	color: #666666;
	margin: 0px;
}

ul, li {
	margin: 0px;
	list-style-type: none;
}


/*---------------------------------------------*/
input {
	outline: none;
	border: none;
}

textarea {
  outline: none;
  border: none;
}

textarea:focus, input:focus {
  border-color: transparent !important;
}







/*------------------------------------------------------------------
[ Input ]*/

.wrap-input100 {
  width: 100%;
  position: relative;
  border-bottom: 2px solid #adadad;
  margin-bottom: 37px;
}

.input100 {
  font-family: Poppins-Regular;
  font-size: 15px;
  color: #555555;
  line-height: 1.2;

  display: block;
  width: 100%;
  height: 45px;
  background: transparent;
  padding: 0 5px;
}

/*---------------------------------------------*/ 
.focus-input100 {
  position: absolute;
  display: block;
  width: 100%;
  height: 100%;
  top: 0;
  left: 0;
  pointer-events: none;
  
}

.focus-input100::before {
  content: "";
  display: block;
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 2px;

  -webkit-transition: all 0.4s;
  -o-transition: all 0.4s;
  -moz-transition: all 0.4s;
  transition: all 0.4s;

  background: #6a7dfe;
  background: -webkit-linear-gradient(left, yellow, #b721ff);
  background: -o-linear-gradient(left, yellow, #b721ff);
  background: -moz-linear-gradient(left, yellow, #b721ff);
  background: linear-gradient(left, yellow, #b721ff);
}

.focus-input100::after {
  font-family: Poppins-Regular;
  font-size: 15px;
  color: #999999;
  line-height: 1.2;

  content: attr(data-placeholder);
  display: block;
  width: 100%;
  position: absolute;
  top: 16px;
  left: 0px;
  padding-left: 5px;

  -webkit-transition: all 0.4s;
  -o-transition: all 0.4s;
  -moz-transition: all 0.4s;
  transition: all 0.4s;
}

.input100:focus + .focus-input100::after {
  top: -15px;
}

.input100:focus + .focus-input100::before {
  width: 100%;
}

.has-val.input100 + .focus-input100::after {
  top: -15px;
}

.has-val.input100 + .focus-input100::before {
  width: 100%;
}










/*------------------------------------------------------------------
[ Responsive ]*/

@media (max-width: 576px) {
  .wrap-login100 {
    padding: 77px 15px 33px 15px;
  }
}



/*------------------------------------------------------------------
[ Alert validate ]*/

.validate-input {
  position: relative;
}

.alert-validate::before {
  content: attr(data-validate);
  position: absolute;
  max-width: 70%;
  background-color: #fff;
  border: 1px solid #c80000;
  border-radius: 2px;
  padding: 4px 25px 4px 10px;
  top: 50%;
  -webkit-transform: translateY(-50%);
  -moz-transform: translateY(-50%);
  -ms-transform: translateY(-50%);
  -o-transform: translateY(-50%);
  transform: translateY(-50%);
  right: 0px;
  pointer-events: none;

  font-family: Poppins-Regular;
  color: #c80000;
  font-size: 13px;
  line-height: 1.4;
  text-align: left;

  visibility: hidden;
  opacity: 0;

  -webkit-transition: opacity 0.4s;
  -o-transition: opacity 0.4s;
  -moz-transition: opacity 0.4s;
  transition: opacity 0.4s;
}

.alert-validate::after {
  content: "\f06a";
  font-family: FontAwesome;
  font-size: 16px;
  color: #c80000;

  display: block;
  position: absolute;
  background-color: #fff;
  top: 50%;
  -webkit-transform: translateY(-50%);
  -moz-transform: translateY(-50%);
  -ms-transform: translateY(-50%);
  -o-transform: translateY(-50%);
  transform: translateY(-50%);
  right: 5px;
}

.alert-validate:hover:before {
  visibility: visible;
  opacity: 1;
}


.limiter {
	width: 20%;
	padding-top: 5%;
}

<div class="limiter">
	<div class="wrap-input100 validate-input">
		<span class="btn-show-pass">
			<i class="zmdi zmdi-eye"></i>
		</span>
		<input class="input100" type="password" name="password">
		<span class="focus-input100" data-placeholder="wachtwoord"></span>
	</div>
</div>

Answer 1

将 CSS border-image 和 border-image-slice 属性添加到 .wrap-input100 类

.wrap-input100 {
  width: 100%;
  position: relative;
  margin-bottom: 37px;
  border-bottom: 2px solid transparent;
  border-image: linear-gradient(to right, #b721ff 0%, red 100%);
  border-image-slice: 1;
}