Animate borders to follow each other css - html

Question

I want to make a border surrounding an HTML element to loop. You can find it in this pen that I managed to make it run once correctly. But, if I add infinite property to the animation it shows all after the first cycle. And this is not what I want in this case. How can I make the lines follow each other infinitely where only one line is visible?
html {
margin: 0;
padding: 0;
}
body {
position: relative;
font-family: sans-serif;
color: #fff;
background-color: #000;
}
.wrapper {
position: absolute;
top: 100%;
left: 50%;
transform: translate(-50%, 25%);
}
.heading-one {
margin: 0;
padding: 0;
border: 1px solid #fff;
padding: 30px;
font-size: 28px;
display: inline-block;
position: relative;
overflow: hidden;
}
.inner-border {
opacity: 0;
}
.inner-border:nth-child(1) {
content: '';
position: absolute;
top: -3px;
left: 0;
width: 80px;
height: 6px;
background-color: #fff;
animation: animate1 1s ease-in alternate;
}
#keyframes animate1 {
0% {
left: 0;
opacity: 1;
}
100% {
left: 100%;
opacity: 1;
}
}
.inner-border:nth-child(2) {
content: '';
position: absolute;
top: 0;
right: -3px;
height: 80px;
width: 6px;
background-color: #fff;
animation: animate2 1s ease-in 1s alternate;
}
#keyframes animate2 {
0% {
top: 0;
opacity: 1;
}
100% {
top: 100%;
opacity: 1;
}
}
.inner-border:nth-child(3) {
content: '';
position: absolute;
bottom: -3px;
right: 0;
height: 6px;
width: 80px;
background-color: #fff;
animation: animate3 1s ease-in 2s alternate;
}
#keyframes animate3 {
0% {
right: 0;
opacity: 1;
}
100% {
right: 100%;
opacity: 1;
}
}
.inner-border:nth-child(4) {
content: '';
position: absolute;
bottom: 0;
left: -3px;
width: 6px;
height: 80px;
background-color: #fff;
animation: animate4 1s ease-in 3s alternate;
}
#keyframes animate4 {
0% {
bottom: 0;
opacity: 1;
}
100% {
bottom: 100%;
opacity: 1;
}
}
<div class="wrapper">
<h1 class="heading-one">We Redefine Interior Designing
<span class="inner-border"></span>
<span class="inner-border"></span>
<span class="inner-border"></span>
<span class="inner-border"></span>
</h1>
</div>

Answer 1

Rather than using the timing offset, integrate the offset into the animation itself. In this way, the #keyframes declarations describe full loops and so can be animated continuously:
.inner-border:nth-child(1) {
content: '';
position: absolute;
top: -3px;
left: 0;
width: 80px;
height: 6px;
background-color: #fff;
animation: animate1 4s ease-in 0s infinite;
}
#keyframes animate1 {
0% {
left: -80px;
opacity: 1;
}
25% {
left: 100%;
opacity: 1;
}
100% {
left: 100%;
opacity: 0;
}
}
.inner-border:nth-child(2) {
content: '';
position: absolute;
top: 0;
right: -3px;
height: 80px;
width: 6px;
background-color: #fff;
animation: animate2 4s ease-in 0s infinite;
}
#keyframes animate2 {
0% {
top: -80px;
opacity: 0;
}
25% {
top: -80px;
opacity: 1;
}
50% {
top: 100%;
opacity: 1;
}
100% {
top: 100%;
opacity: 0;
}
}
.inner-border:nth-child(3) {
content: '';
position: absolute;
bottom: -3px;
right: 0;
height: 6px;
width: 80px;
background-color: #fff;
animation: animate3 4s ease-in infinite;
}
#keyframes animate3 {
0% {
right: -80px;
opacity: 0;
}
50% {
right: -80px;
opacity: 1;
}
75% {
right: 100%;
opacity: 1;
}
100% {
right: 100%;
opacity: 0;
}
}
.inner-border:nth-child(4) {
content: '';
position: absolute;
bottom: 0;
left: -3px;
width: 6px;
height: 80px;
background-color: #fff;
animation: animate4 4s ease-in infinite;
}
#keyframes animate4 {
0% {
bottom: -80px;
opacity: 0;
}
75% {
bottom: -80px;
opacity: 1;
}
100% {
bottom: 100%;
opacity: 1;
}
}