CSS Accordion | Learning Axis

HTML

CSS

:root {
  --radius: 16px;
  --gap: 12px;
  --transition: 0.5s cubic-bezier(.25,.9,.25,1);
  --bg: #fafafa;
  --text: #222;
  --accent1: #ff6b6b;
  --accent2: #00c3ff;
  --accent3: #7b61ff;
}
body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  flex-direction:column;
  justify-content: center;
  align-items: center;
  background: var(--bg);
  color: var(--text);
  font-family: "Inter", system-ui, sans-serif;
}
.accordion {
  display: flex;
  gap: var(--gap);
  width: min(1000px, 95vw);
  height: 280px;
}
details {
  flex: 0 0 90px;
  border-radius: var(--radius);
  overflow: hidden;
  background: white;
  box-shadow: 0 4px 16px rgba(0,0,0,0.08);
  transition: flex-basis var(--transition), transform var(--transition);
  position: relative;
}
details[open] {
  flex: 1 1 auto;
  transform: translateY(-4px);
}
summary {
  writing-mode: vertical-rl;
  text-orientation: mixed;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 12px;
  font-weight: 600;
  font-size: 14px;
  cursor: pointer;
  list-style: none;
  color: white;
  background: var(--accent1);
  transition: opacity var(--transition), background var(--transition);
  user-select: none;
}
details:nth-child(2) summary { background: var(--accent2); }
details:nth-child(3) summary { background: var(--accent3); }
summary::-webkit-details-marker { display: none; }
details[open] summary {
  pointer-events: none;
}
.content {
  position: absolute;
  inset: 0;
  padding: 30px 40px;
  background: white;
  opacity: 0;
  transform: translateX(40px);
  transition: opacity var(--transition), transform var(--transition);
  display: flex;
  flex-direction: column;
  justify-content: center;
}
details[open] .content {
  opacity: 1;
  transform: translateX(0);
  position:initial
}
.content h3 {
  margin-top: 0;
  font-size: 1.5rem;
}
.content p {
  color: #555;
  line-height: 1.5;
  max-width: 480px;
}
@media (max-width:700px) {
  .accordion {
    flex-direction: column;
    height: auto;
  }
  details {
    flex: 1 1 auto;
  }
  summary {
    writing-mode: horizontal-tb;
  }
}