style.css

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

:root {
  --line-border-fill: #3498db;
  --line-border-empty: #e0e0e0;
}

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

html, body {
  height: 100%;
  width: 100%;
  font-family: roboto;
}

body{
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: lightblue;
}

.container{
  display: flex;
  flex-direction: column;
  gap: 2em;
  max-width: 100%;
  /* background-color: red; */
  text-align: center;
  position: relative;
}

.top{
  display: flex;
  gap: 8em;
  align-items: center;
  justify-content: space-between;
}

.top::before{
  content: "";
  position: absolute;
  background-color: var(--line-border-empty);
  /* transform: translateY(-50%); */
  height: 4px;
  width: 100%;
  z-index: -1;
  /* transition: 0.4s ease; */
}


.top .line{
  position: absolute;
  background-color: var(--line-border-fill);
  /* transform: translateY(-50%); */
  height: 4px;
  width: 0%;
  z-index: -1;
  transition: 0.4s ease;
}

.top .line .blue{
  position: absolute;
  background-color: red;
  height: 4px;
  width: 100%;
  z-index: 2;
}

.circle{
  background-color: white;
  color: #999;
  border-radius: 50%;
  height: 30px;
  width: 30px;
  display: flex;
  align-items: center;
  justify-content: center;
  border: var(--line-border-empty) solid 3px;
  transition: 0.4s ease;
}

.circle.active{
  border-color: var(--line-border-fill);
}

.btn {
  background-color: var(--line-border-fill);
  color: white;
  padding: 1em 3em;
  border-radius: 5px;
  cursor: pointer;
  border: none;
  /* outline: none; */
  margin: 1em;
}

.btn:active{
  transform: scale(0.9);
}

/* .btn:focus{
  outline: 0;
} */

.btn:disabled{
  background-color: var(--line-border-empty);
  color: black;
  cursor: not-allowed;
  pointer-events: none;
}