/* ============================================================
   AI section: "3つのAIで、人材を育てる。"
   Shared header/inner/title/lead come from section.css.
   ============================================================ */
.ai-cards {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: clamp(20px, 2.5vw, 32px);
}

.ai-card {
  position: relative;
  border-radius: 24px;
  padding: clamp(28px, 3vw, 40px);
  background: var(--ac-bg, #ecf4fb);
  display: flex;
  flex-direction: column;
  gap: 16px;
  overflow: hidden;
  box-shadow: 0 18px 40px -24px rgba(13, 30, 60, 0.2),
              0 2px 6px -2px rgba(13, 30, 60, 0.04);
}

/* Content sits above the corner watermark */
.ai-card > * {
  position: relative;
  z-index: 1;
}

.ai-card::after {
  position: absolute;
  bottom: -42px;
  right: -16px;
  font-family: "Nunito", "Noto Sans JP", sans-serif;
  font-size: clamp(140px, 18vw, 220px);
  font-weight: 900;
  line-height: 0.85;
  letter-spacing: -0.05em;
  color: var(--ac-num);
  pointer-events: none;
  z-index: 0;
}

.ai-card--blue {
  --ac-bg: #ecf4fb;
  --ac-num: rgba(46, 146, 214, 0.18);
}
.ai-card--blue::after { content: "01"; }

.ai-card--orange {
  --ac-bg: #fdeede;
  --ac-num: rgba(237, 111, 37, 0.18);
}
.ai-card--orange::after { content: "02"; }

.ai-card--gray {
  --ac-bg: #eff1f5;
  --ac-num: rgba(103, 115, 131, 0.22);
}
.ai-card--gray::after { content: "03"; }

.ai-card__title {
  font-size: clamp(20px, 2.2vw, 26px);
  font-weight: 900;
  color: var(--text);
  line-height: 1.4;
  letter-spacing: 0.01em;
}

.ai-card__desc {
  font-size: clamp(13px, 1.05vw, 14px);
  line-height: 1.95;
  color: #5b6975;
  font-weight: 500;
}

/* Tablet */
@media (max-width: 900px) {
  .ai-cards {
    grid-template-columns: repeat(2, 1fr);
  }
  .ai-card:nth-child(3) {
    grid-column: 1 / -1;
    max-width: calc(50% - 12px);
    margin: 0 auto;
  }
}

/* Mobile */
@media (max-width: 600px) {
  .ai-cards {
    grid-template-columns: 1fr;
  }
  .ai-card:nth-child(3) {
    max-width: 100%;
    margin: 0;
  }
}