Bản mẫu:4-tab/styles.css

* {
  font-family: sans-serif;
}

h3 {
  text-align: center;
}

.problems {
  display: none;
  justify-content: space-between;
  margin: 0 2em;
  cursor: pointer;
  position: relative;
}
.problems.prob {
  display: flex;
  background-color: #efefef;
}
.problems.prob .problem {
  flex-grow: 1;
  text-align: center;
  position: relative;
  z-index: 1;
  transition: 0.25s;
}
.problems.prob .problem.active, .problems.prob .problem:hover {
  color: #fff;
}
.problems.prob .focus {
  position: absolute;
  width: 25%;
  height: 100%;
  background: linear-gradient(to right, #A3CC63 75%, green 300%);
  left: 0;
  transition: 0.25s;
}
.problems.prob .focus.p1 {
  transform: translateX(0);
}
.problems.prob .focus.p2 {
  transform: translateX(100%);
  background: linear-gradient(to right, #A3CC63 50%, green 150%);
}
.problems.prob .focus.p3 {
  transform: translateX(200%);
  background: linear-gradient(to right, #A3CC63 25%, green 100%);
}
.problems.prob .focus.p4 {
  transform: translateX(300%);
  background: linear-gradient(to right, #A3CC63 0%, green 50%);
}

.probs {
  padding: 2em 2em 0;
  text-align: justify;
}
.probs .prob {
  display: none;
}
.probs .prob:last-child {
  padding-top: 2em;
}
.probs .prob.active {
  display: block;
}

a {
  color: green;
  margin: auto;
}

.wrap {
  border: 1px solid #A3CC63;
  margin: 0 2em;
  box-shadow: 0 2px 3px rgba(0, 0, 0, 0.1);
  padding-bottom: 3em;
}