.page-container {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

.content-wrap {
  flex: 1;
}

.main-content {
  display: flex;
  justify-content: center;
  width: 100%;
}

.content-container {
  display: flex;
  align-items: flex-start;
  max-width: 1200px;
  width: 100%;
  padding: 20px;
  gap: 20px;
}

.middle-section {
  display: flex;
  flex-direction: column;
  width: calc(85% - 14px);
  flex: 0 0 calc(85% - 14px);
  min-width: 0;
}

.right-sidebar {
  position: sticky;
  top: 60px;
  width: calc(15% - 6px);
  flex: 0 0 calc(15% - 6px);
  min-width: calc(15% - 6px);
  height: 100vh;
}

.calculus3-section {
  position: relative;
  overflow: hidden;
  background:
    radial-gradient(circle at 16% 22%, rgba(255, 210, 122, 0.42) 0%, transparent 30%),
    radial-gradient(circle at 84% 20%, rgba(168, 199, 255, 0.40) 0%, transparent 30%),
    radial-gradient(circle at 50% 85%, rgba(170, 245, 232, 0.34) 0%, transparent 34%),
    linear-gradient(135deg, #fff4d6 0%, #ffd9ee 28%, #d8e8ff 62%, #d8fff5 100%);
  min-height: 500px;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 36px 20px;
  box-sizing: border-box;
}

.calculus3-section::before {
  content: "";
  position: absolute;
  inset: 0;
  background:
    linear-gradient(120deg, rgba(255, 255, 255, 0.24) 0%, transparent 45%, rgba(255, 255, 255, 0.14) 100%);
  pointer-events: none;
}

.calculus3-container {
  position: relative;
  z-index: 1;
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  text-align: center;
}

.calculus3-hero-content {
  max-width: 760px;
  margin: 0 auto;
}

.calculus3-kicker {
  display: inline-block;
  margin-bottom: 12px;
  padding: 5px 12px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.55);
  border: 1px solid rgba(0, 0, 0, 0.06);
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: #4a4a4a;
}

.calculus3-title {
  font-size: 56px;
  font-weight: 800;
  line-height: 1.05;
  margin: 0;
  color: #111111;
}

.calculus3-divider {
  width: 76px;
  height: 4px;
  margin: 14px auto 16px;
  border-radius: 999px;
  background: linear-gradient(90deg, #ffbf69 0%, #ff8fab 50%, #7db7ff 100%);
}

.calculus3-description {
  max-width: 620px;
  margin: 0 auto;
  font-size: 1.08rem;
  line-height: 1.7;
  color: #222222;
}

.topics-container {
  width: 100%;
  padding: 40px 0 60px;
}

.topic-group {
  margin-bottom: 55px;
}

.topic-group:last-child {
  margin-bottom: 0;
}

.topic-group-header {
  text-align: left;
  margin-bottom: 22px;
}

.topic-group-title {
  font-size: 2rem;
  font-weight: 700;
  margin: 0 0 8px;
  color: #1f1f1f;
}

.topic-group-description {
  margin: 0;
  font-size: 1rem;
  color: #5e5e5e;
  line-height: 1.6;
}

.topics-cards {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 20px;
}

.topic-card {
  background-color: #f4f4f4;
  border: 1px solid #ddd;
  border-radius: 8px;
  box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
  transition: transform 0.3s, box-shadow 0.3s;
  padding: 15px;
  text-align: center;
  min-height: 96px;
  display: flex;
  align-items: center;
  justify-content: center;
  box-sizing: border-box;
}

.topic-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 6px 14px rgba(0, 0, 0, 0.12);
}

.topic-card a {
  text-decoration: none;
  color: inherit;
  width: 100%;
  display: block;
}

.topic-title {
  font-size: 1rem;
  margin: 0;
  line-height: 1.45;
}

.topic-card.coming-soon {
  background-color: #fafafa;
}

.topic-card.coming-soon:hover {
  transform: none;
  box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
}

.topic-card.coming-soon .coming-soon-wrapper {
  pointer-events: none;
  text-align: center;
  opacity: 0.7;
  padding: 0.25rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  width: 100%;
}

.coming-soon-badge {
  display: inline-block;
  margin-top: 10px;
  font-size: 0.75rem;
  font-weight: bold;
  padding: 4px 8px;
  border-radius: 3px;
  background-color: #ffecb3;
  color: #8a6d3b;
  white-space: nowrap;
}

.new-badge {
  display: inline-block;
  margin-top: 10px;
  font-size: 0.75rem;
  font-weight: bold;
  padding: 4px 8px;
  border-radius: 3px;
  background-color: #ffcccc;
  color: #b30000;
  white-space: nowrap;
}