/* ============================================================
   mechanism.css — 水素のしくみページ専用
   ============================================================ */

/* ── ヒーロー ── */
.mec-hero {
  padding-top: calc(64px + clamp(4rem, 8vw, 7rem));
  padding-bottom: clamp(3.5rem, 7vw, 6rem);
  padding-left: var(--pad-x);
  padding-right: var(--pad-x);
  background: linear-gradient(160deg, #f8fafc 0%, #edf5fb 55%, #f4f8fc 100%);
  border-bottom: 1px solid var(--border-light);
  position: relative;
  overflow: hidden;
}
.mec-hero::before {
  content: '';
  position: absolute;
  top: -20%; right: -8%;
  width: clamp(300px, 50vw, 600px);
  height: clamp(300px, 50vw, 600px);
  border-radius: 50%;
  background: radial-gradient(circle, rgba(200,223,240,.3) 0%, transparent 70%);
  filter: blur(60px);
  pointer-events: none;
}
.mec-hero-inner { position: relative; z-index: 1; }
.mec-h1 {
  font-size: clamp(1.9rem, 4.5vw, 3rem);
  font-weight: 300;
  font-family: var(--font-serif);
  color: var(--navy);
  line-height: 1.35;
  margin-bottom: 1.2rem;
}
.mec-lead {
  font-size: clamp(1rem, 1.5vw, 1.08rem);
  color: var(--text-mid);
  font-weight: 300;
  line-height: 2;
  max-width: 560px;
}

/* ── 図解セクション ── */
.mec-figures { background: var(--white); }
.mec-figure {
  margin-bottom: clamp(3rem, 6vw, 5rem);
  padding-bottom: clamp(3rem, 6vw, 5rem);
  border-bottom: 1px solid var(--border-light);
}
.mec-figure:last-of-type { border-bottom: none; }

.mec-figure-header { margin-bottom: 1.8rem; }
.mec-figure-title {
  font-family: var(--font-serif);
  font-size: clamp(1.2rem, 2.2vw, 1.6rem);
  font-weight: 300;
  color: var(--navy);
  line-height: 1.4;
  margin: .5rem 0 .8rem;
}
.mec-figure-desc {
  font-size: clamp(.9rem, 1.3vw, .97rem);
  color: var(--text-mid);
  font-weight: 300;
  line-height: 1.9;
  max-width: 580px;
}

/* 画像ラッパー */
.mec-img-wrap {
  border-radius: 6px;
  overflow: hidden;
  box-shadow: 0 4px 24px rgba(0,0,0,.07), 0 1px 4px rgba(0,0,0,.04);
  background: var(--off-white);
  display: flex;
  align-items: center;
  justify-content: center;
}
.mec-img {
  display: block;
  width: 100%;
  height: auto;
  /* 元の比率を必ず維持 */
  object-fit: contain;
}

/* ── 注意書き ── */
.mec-notices {
  padding: 1.2rem 1.5rem;
  background: var(--off-white);
  border: 1px solid var(--border-light);
  display: flex;
  flex-direction: column;
  gap: .4rem;
}
.mec-notices p {
  font-size: .78rem;
  color: var(--muted);
  font-weight: 300;
  line-height: 1.7;
}

/* ── CTA ── */
.mec-cta {
  background: var(--navy);
  padding: clamp(4rem, 8vw, 7rem) var(--pad-x);
  text-align: center;
  position: relative;
  overflow: hidden;
}
.mec-cta::before {
  content: '';
  position: absolute;
  top: 50%; left: 50%;
  transform: translate(-50%, -50%);
  width: 600px; height: 600px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(74,144,184,.1) 0%, transparent 65%);
  pointer-events: none;
}
.mec-cta-inner { position: relative; z-index: 1; }
.mec-cta h2 {
  color: var(--white);
  font-size: clamp(1.3rem, 2.8vw, 2rem);
}
.mec-cta-btns {
  display: flex;
  gap: .8rem;
  justify-content: center;
  flex-wrap: wrap;
}
.mec-cta .btn-primary {
  background: var(--white);
  color: var(--navy);
  border-color: var(--white);
}
.mec-cta .btn-primary:hover { background: var(--blue-pale); border-color: var(--blue-pale); }
.mec-cta .btn-outline {
  border-color: rgba(255,255,255,.3);
  color: rgba(255,255,255,.8);
}
.mec-cta .btn-outline:hover { border-color: var(--white); color: var(--white); }
.mec-cta-note {
  margin-top: 1.5rem;
  font-size: .74rem;
  color: rgba(255,255,255,.28);
  letter-spacing: .06em;
}

/* ── Responsive ── */
@media (max-width: 768px) {
  .mec-cta-btns { flex-direction: column; align-items: center; }
  .mec-cta .btn-primary { font-size: .85rem; }
}