@import url('https://fonts.googleapis.com/css?family=Muli&display=swap');
:root {
  --line-border-fill: #3498db;
  --line-border-empty: #e0e0e0;
}
* {
  box-sizing: border-box;
}
body {
  background-color: #f6f7fb;
  font-family: 'Muli', sans-serif;
  display: flex;
  align-items: center;
  justify-content: center;
  height: 100vh;
  overflow: hidden;
  margin: 0;
}
.container {
  display: flex;
  flex-wrap: wrap;
  width: 50vw;
}
.progress-container {
  overflow: hidden;
  position: relative;
  display: flex;
  width: 100%;
  max-width: 100%;
  justify-content: space-between;
  margin-bottom: 50px;
}
/*灰色横轴*/
.progress-container::before {
  content: '';
  display: block;
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  width: 100%;
  height: 4px;
  background-color: var(--line-border-empty);
}
/*高亮横轴*/
.progress-line {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  height: 4px;
  background-color: var(--line-border-fill);
  transition: width .4s ease;
}
.step {
  position: relative;
  display: flex;
  justify-content: center;
  align-items: center;
  width: 30px;
  height: 30px;
  border-radius: 50%;
  border: 3px solid var(--line-border-empty);
  background-color: #fff;
  z-index: 9;
  transition: border .4s ease-in;
}
.step.active {
  border: 3px solid var(--line-border-fill);
}
.stepBtn {
  display: flex;
  width: 100%;
  justify-content: center;
}
button {
  margin: 5px;
  padding: 8px 30px;
  color: #fff;
  border: 0;
  outline: 0;
  font-size: 14px;
  border-radius: 6px;
  background-color: var(--line-border-fill);
  cursor: pointer;
}
button:active {
  transform: scale(.98);
}
.disabled {
  cursor:not-allowed;
  background-color: var(--line-border-empty);
}