.about-notebook {
  width: min(100%, 1040px);
}

@media (max-width: 400px) {
  .about-notebook .about-heading h1 { font-size: 1.65rem; }
  .about-notebook .about-story-section h2,
  .about-notebook .about-feature-card h2 { font-size: 1.4rem; }
}

.about-header {
  display: grid;
  gap: clamp(36px, 6vw, 64px);
  padding-bottom: clamp(40px, 7vw, 72px);
}

.about-brand-name {
  color: var(--ink);
  font-size: clamp(1.45rem, 4vw, 2rem);
  text-decoration: none;
}

.about-heading {
  max-width: 760px;
}

.about-heading h1 {
  margin-bottom: 18px;
  font-size: clamp(2.15rem, 7vw, 3.7rem);
  line-height: 1.23;
}

.about-heading .lead {
  max-width: 680px;
  margin: 0;
  color: var(--color-text-secondary);
  font-size: clamp(1rem, 2vw, 1.15rem);
  line-height: 1.9;
}

.about-story-section,
.about-feature-card {
  display: grid;
  grid-template-columns: minmax(0, 1.15fr) minmax(260px, 0.85fr);
  align-items: center;
  gap: clamp(28px, 6vw, 72px);
  padding: clamp(36px, 7vw, 72px) clamp(24px, 5vw, 56px);
}

.about-story-section {
  border-radius: var(--radius-lg);
  background: #f5f9fa;
}

.about-story-section > div,
.about-feature-card > div {
  max-width: 560px;
}

.about-story-section h2,
.about-feature-card h2 {
  margin: 8px 0 14px;
  font-size: clamp(1.65rem, 4vw, 2.4rem);
  line-height: 1.35;
}

.about-story-section p:last-child,
.about-feature-card p:last-child {
  margin: 0;
  color: var(--color-text-secondary);
  line-height: 1.9;
}

.about-story-section img,
.about-story-section .about-learning-diagram,
.about-feature-card img {
  display: block;
  width: min(100%, 390px);
  height: auto;
  margin: 0 auto;
  border-radius: var(--radius-lg);
}

.about-feature-list {
  display: grid;
  gap: 0;
  margin-top: clamp(36px, 7vw, 72px);
}

.about-feature-card {
  border: 0;
  border-top: 1px solid var(--color-border-light);
  border-radius: 0;
  background: var(--color-surface);
  box-shadow: none;
}

.about-feature-card:nth-child(odd) img {
  order: 2;
}

.about-feature-card.is-support {
  background: var(--color-surface-subtle);
}

.about-start {
  display: grid;
  justify-items: start;
  gap: 10px;
  margin-top: clamp(36px, 7vw, 72px);
  padding: clamp(28px, 5vw, 48px);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-lg);
  background: var(--color-surface);
  box-shadow: none;
}

.about-start h2,
.about-start p {
  margin-bottom: 0;
}

.about-start .primary-button {
  width: auto;
  margin-top: 8px;
  text-decoration: none;
}

@media (max-width: 720px) {
  .about-notebook .no-break { white-space: normal; display: inline; }
  .about-story-section,
  .about-feature-card {
    grid-template-columns: 1fr;
    gap: 24px;
    padding: 32px 22px;
  }

  .about-story-section img,
  .about-feature-card img,
  .about-feature-card:nth-child(odd) img {
    order: 2;
    width: min(100%, 340px);
  }

  .about-feature-card {
    padding-left: 0;
    padding-right: 0;
  }

  .about-feature-card.is-support {
    margin-right: -20px;
    margin-left: -20px;
    padding-right: 20px;
    padding-left: 20px;
  }

  .about-start .primary-button {
    width: 100%;
  }
}