/* ==========================================================================
   名智 · 慢展开滚动揭示（IntersectionObserver 驱动）
   4 类产品（户外/家用/烧烤/取暖）+ 可定制能力
   ========================================================================== */

/* ============ Hero ============ */
.hero {
  position: relative;
  min-height: 100dvh;
  display: flex;
  align-items: center;
  overflow: hidden;
  isolation: isolate;
}

.hero__bg {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  z-index: -2;
  object-fit: cover;
  object-position: center;
  filter: none;
}

.hero__veil {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse at 70% 30%, rgba(255,106,44,0.15) 0%, transparent 50%),
    linear-gradient(180deg, rgba(10,11,13,0.4) 0%, rgba(10,11,13,0.7) 60%, rgba(10,11,13,0.95) 100%);
  z-index: -1;
}

.hero__inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 32px;
  width: 100%;
  padding-top: 120px;
}

.hero__title {
  font-family: "Instrument Serif", "Source Han Serif", serif;
  font-size: clamp(56px, 8vw, 120px);
  line-height: 1.0;
  font-weight: 400;
  letter-spacing: -0.03em;
  color: var(--text);
  margin: 16px 0 32px;
  max-width: 900px;
}

.hero__title em {
  font-style: italic;
  color: var(--accent);
}

.hero__lead {
  font-size: 18px;
  line-height: 1.6;
  color: var(--text-mute);
  max-width: 560px;
  margin: 0 0 40px;
}

.hero .eyebrow {
  font-family: "JetBrains Mono", monospace;
  font-size: 12px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent);
  margin: 0;
}

.cta-row {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 16px 28px;
  border-radius: 999px;
  font-size: 15px;
  font-weight: 500;
  text-decoration: none;
  border: 1px solid transparent;
  transition: transform 0.3s, background 0.3s, border-color 0.3s;
}

.btn .arrow { transition: transform 0.3s; }
.btn:hover .arrow { transform: translateX(4px); }
.btn:hover { transform: scale(0.98); }

.btn--primary {
  background: var(--accent);
  color: var(--bg-primary);
}
.btn--primary:hover { background: #ff7a3d; }

.btn--ghost {
  background: transparent;
  color: var(--text);
  border-color: var(--line-strong);
}
.btn--ghost:hover { border-color: var(--accent); color: var(--accent); }

.btn--lg {
  padding: 20px 36px;
  font-size: 16px;
}

.hero__scroll-hint {
  position: absolute;
  bottom: 40px;
  left: 50%;
  transform: translateX(-50%);
  text-align: center;
  font-family: "JetBrains Mono", monospace;
  font-size: 11px;
  letter-spacing: 0.12em;
  color: var(--text-mute);
  text-transform: uppercase;
}

.hero__scroll-hint .arrow-down {
  display: block;
  margin-top: 8px;
  animation: bob 2s ease-in-out infinite;
}

@keyframes bob {
  0%, 100% { transform: translateY(0); opacity: 0.6; }
  50% { transform: translateY(8px); opacity: 1; }
}

/* ============ Trust Bar ============ */
.trust {
  background: var(--bg-elev);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  padding: 32px 0;
}

.trust__inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 32px;
  display: flex;
  align-items: center;
  justify-content: space-around;
  gap: 24px;
  flex-wrap: wrap;
}

.trust__item {
  text-align: center;
}

.trust__num {
  font-family: "Instrument Serif", serif;
  font-size: 36px;
  font-weight: 400;
  color: var(--text);
  line-height: 1;
}

.trust__num small {
  font-size: 18px;
  color: var(--accent);
  margin-left: 2px;
}

.trust__label {
  font-size: 12px;
  color: var(--text-mute);
  margin: 6px 0 0;
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.trust__certs {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  justify-content: center;
}

.trust__certs span {
  padding: 6px 12px;
  border: 1px solid var(--line-strong);
  border-radius: 4px;
  font-family: "JetBrains Mono", monospace;
  font-size: 12px;
  color: var(--text);
  letter-spacing: 0.04em;
}

.trust__divider {
  width: 1px;
  height: 40px;
  background: var(--line);
}

/* ============ 慢展开段（4 类产品） ============ */
.expand {
  position: relative;
  min-height: 80vh;
  display: grid;
  grid-template-columns: 1fr 1fr;
  align-items: center;
  background: var(--bg-primary);
  overflow: hidden;
}

.expand--alt { background: var(--bg-elev); }

.expand__visual {
  position: relative;
  width: 100%;
  height: 100%;
  min-height: 600px;
  object-fit: cover;
  object-position: center;
  background-color: #0d0e10;
}

.expand__visual::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(to right, transparent 60%, var(--bg-primary) 100%);
}

.expand--alt .expand__visual::after {
  background: linear-gradient(to left, transparent 60%, var(--bg-elev) 100%);
}

.expand__inner {
  padding: 80px 60px;
  max-width: 600px;
}

.expand--alt .expand__inner { order: 2; }
.expand--alt .expand__visual { order: 1; }

.expand .eyebrow.mono {
  font-family: "JetBrains Mono", monospace;
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--accent);
  margin: 0 0 16px;
}

.expand__title {
  font-family: "Instrument Serif", "Source Han Serif", serif;
  font-size: clamp(40px, 4.5vw, 64px);
  line-height: 1.05;
  font-weight: 400;
  letter-spacing: -0.02em;
  color: var(--text);
  margin: 0 0 24px;
}

.expand__lead {
  font-size: 17px;
  line-height: 1.6;
  color: var(--text-mute);
  margin: 0 0 32px;
}

.expand__bullets {
  list-style: none;
  padding: 0;
  margin: 0 0 32px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.expand__bullets li {
  padding-left: 20px;
  position: relative;
  color: var(--text);
  font-size: 15px;
  line-height: 1.5;
}

.expand__bullets li::before {
  content: "—";
  position: absolute;
  left: 0;
  color: var(--accent);
  font-weight: 500;
}

.link-arrow {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: var(--accent);
  text-decoration: none;
  font-weight: 500;
  transition: gap 0.3s;
}

.link-arrow:hover { gap: 10px; }

/* ============ 可定制能力 ============ */
.custom {
  background: linear-gradient(135deg, var(--accent) 0%, #ff4a14 100%);
  color: var(--bg-primary);
  padding: 140px 0;
  text-align: center;
  position: relative;
  overflow: hidden;
}

.custom::before {
  content: "CUSTOM";
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  font-family: "Instrument Serif", serif;
  font-size: clamp(140px, 22vw, 320px);
  font-style: italic;
  color: rgba(0,0,0,0.06);
  letter-spacing: -0.05em;
  pointer-events: none;
  z-index: 0;
}

.custom__inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 32px;
  position: relative;
  z-index: 1;
}

.custom .eyebrow {
  font-family: "JetBrains Mono", monospace;
  font-size: 12px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: rgba(10,11,13,0.7);
  margin: 0 0 16px;
}

.custom__title {
  font-family: "Instrument Serif", "Source Han Serif", serif;
  font-size: clamp(48px, 7vw, 96px);
  line-height: 1.0;
  font-weight: 400;
  letter-spacing: -0.03em;
  margin: 0 0 32px;
}

.custom__title em {
  font-style: italic;
  color: rgba(10,11,13,0.85);
}

.custom__lead {
  font-size: 18px;
  line-height: 1.6;
  max-width: 700px;
  margin: 0 auto 60px;
  opacity: 0.85;
}

.custom__grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 32px;
  margin: 0 0 60px;
}

.custom__item {
  border-top: 1px solid rgba(10,11,13,0.3);
  padding-top: 24px;
  text-align: left;
}

.custom__num {
  font-family: "Instrument Serif", serif;
  font-size: 48px;
  line-height: 1;
  margin: 0 0 8px;
  font-weight: 400;
}

.custom__num small {
  font-size: 22px;
  margin-left: 2px;
  font-style: italic;
  opacity: 0.7;
}

.custom__label {
  font-size: 14px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin: 0;
  opacity: 0.7;
}

.custom .btn--primary {
  background: var(--bg-primary);
  color: var(--accent);
}

.custom .btn--primary:hover {
  background: #000;
  color: var(--text);
}

/* ============ 工程能力 ============ */
.engineering {
  background: var(--bg-elev);
  padding: 120px 0;
}

.engineering .section__head {
  max-width: 1200px;
  margin: 0 auto 60px;
  padding: 0 32px;
  text-align: left;
}

.engineering .section__title {
  font-family: "Instrument Serif", "Source Han Serif", serif;
  font-size: clamp(40px, 5vw, 64px);
  line-height: 1.05;
  font-weight: 400;
  letter-spacing: -0.02em;
  color: var(--text);
  margin: 12px 0 0;
}

.eyebrow {
  font-family: "JetBrains Mono", monospace;
  font-size: 12px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent);
  margin: 0;
}

.engineering__grid {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 32px;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.eng__card {
  background: var(--bg-primary);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 40px 32px;
  transition: border-color 0.3s, transform 0.3s;
}

.eng__card:hover {
  border-color: var(--accent);
  transform: translateY(-4px);
}

.eng__num {
  font-family: "JetBrains Mono", monospace;
  font-size: 14px;
  color: var(--accent);
  margin: 0 0 16px;
  letter-spacing: 0.08em;
}

.eng__card h3 {
  font-family: "Instrument Serif", "Source Han Serif", serif;
  font-size: 26px;
  font-weight: 400;
  color: var(--text);
  margin: 0 0 16px;
  line-height: 1.2;
}

.eng__card p {
  font-size: 15px;
  line-height: 1.6;
  color: var(--text-mute);
  margin: 0;
}

/* ============ CTA Final ============ */
.cta-final {
  background: var(--bg-primary);
  padding: 140px 0;
  text-align: center;
  border-top: 1px solid var(--line);
}

.cta-final__inner {
  max-width: 900px;
  margin: 0 auto;
  padding: 0 32px;
}

.cta-final h2 {
  font-family: "Instrument Serif", "Source Han Serif", serif;
  font-size: clamp(40px, 5vw, 72px);
  line-height: 1.1;
  font-weight: 400;
  letter-spacing: -0.02em;
  color: var(--text);
  margin: 0 0 24px;
}

.cta-final p {
  font-size: 18px;
  color: var(--text-mute);
  margin: 0 0 40px;
}

/* ============ Reveal 动画 ============ */
.reveal {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.9s var(--ease), transform 0.9s var(--ease);
}

.reveal.is-visible {
  opacity: 1;
  transform: translateY(0);
}

/* 响应式 */
@media (max-width: 768px) {
  .hero__title { font-size: 48px; }
  .hero__inner { padding-top: 100px; }
  .trust__inner { flex-direction: column; gap: 24px; }
  .trust__divider { display: none; }
  .expand { grid-template-columns: 1fr; }
  .expand__visual { min-height: 300px; }
  .expand--alt .expand__inner { order: 1; }
  .expand--alt .expand__visual { order: 2; }
  .expand__inner { padding: 60px 24px; }
  .custom__grid { grid-template-columns: repeat(2, 1fr); }
  .engineering__grid { grid-template-columns: 1fr; }
  .hero__scroll-hint { display: none; }
  .hero__lead { font-size: 16px; }
  .custom { padding: 80px 0; }
  .custom__title { font-size: 48px; }
  .section__head { text-align: left; }
}