/* =========================================================
   森林源木业有限公司 · 官网样式
   色调：胡桃深棕 / 象牙米白 / 香槟金
   ========================================================= */

:root {
  --espresso: #1c1612;
  --walnut: #2b211b;
  --walnut-2: #3a2c22;
  --oak: #8a6440;
  --gold: #c19a62;
  --gold-light: #dcc092;
  --ivory: #f6f1e9;
  --cream: #ede4d6;
  --ink: #2a221c;
  --muted: #7a6c5f;
  --line: rgba(193, 154, 98, .35);

  --serif: "Noto Serif SC", "Source Han Serif SC", "Source Han Serif CN", "Songti SC", "STSong", "SimSun", serif;
  --sans: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", system-ui, sans-serif;

  --header-h: 76px;
  --ease: cubic-bezier(.22, .61, .36, 1);

  /* 木纹噪点 */
  --grain: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='300' height='300'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.006 .18' numOctaves='2' seed='7'/%3E%3CfeColorMatrix values='0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 .32 0'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
}

*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: var(--header-h); -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  font-family: var(--sans);
  color: var(--ink);
  background: var(--ivory);
  line-height: 1.8;
  -webkit-font-smoothing: antialiased;
}
img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
button { font: inherit; cursor: pointer; }
h1, h2, h3, h4 { font-family: var(--serif); font-weight: 600; margin: 0; line-height: 1.35; }
p { margin: 0; }
body.no-scroll { overflow: hidden; }

.container { width: min(1200px, 100% - 48px); margin-inline: auto; }

/* ---------- 按钮 ---------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center;
  padding: 14px 34px; font-size: 15px; letter-spacing: .2em;
  border: 1px solid transparent; transition: all .35s var(--ease);
}
.btn-gold { background: var(--gold); color: var(--espresso); }
.btn-gold:hover { background: var(--gold-light); transform: translateY(-2px); }
.btn-ghost { border-color: rgba(255,255,255,.55); color: #fff; }
.btn-ghost:hover { background: rgba(255,255,255,.12); border-color: #fff; }

/* ---------- 通用标题 ---------- */
.section { padding: 120px 0; position: relative; }
.eyebrow {
  font-size: 12px; letter-spacing: .38em; color: var(--gold);
  font-family: var(--sans); text-transform: uppercase; margin-bottom: 14px;
}
.section-head { text-align: center; max-width: 680px; margin: 0 auto 64px; }
.section-head h2 { font-size: clamp(30px, 4vw, 44px); letter-spacing: .12em; color: var(--espresso); }
.section-head h2::after {
  content: ""; display: block; width: 48px; height: 1px; background: var(--gold); margin: 22px auto 0;
}
.section-desc { margin-top: 22px; color: var(--muted); font-size: 16px; }
.section-head--light h2 { color: #fff; }
.section-head--light .section-desc { color: rgba(255,255,255,.75); }

/* ---------- 导航 ---------- */
.site-header {
  position: fixed; inset: 0 0 auto; z-index: 100; height: var(--header-h);
  color: #fff; transition: background .4s var(--ease), box-shadow .4s, height .4s;
}
.site-header.is-scrolled {
  background: rgba(28, 22, 18, .92); backdrop-filter: blur(10px); -webkit-backdrop-filter: blur(10px);
  box-shadow: 0 1px 0 var(--line); --header-h: 64px;
}
.nav-wrap { height: 100%; display: flex; align-items: center; justify-content: space-between; }
.logo { display: flex; align-items: center; gap: 12px; color: var(--gold-light); }
.logo-mark { width: 42px; height: 42px; flex-shrink: 0; }
.logo-text { display: flex; flex-direction: column; line-height: 1.2; }
.logo-text strong { font-family: var(--serif); font-size: 20px; letter-spacing: .18em; color: #fff; }
.logo-text small { font-size: 9px; letter-spacing: .32em; color: var(--gold); margin-top: 3px; }

.main-nav { display: flex; align-items: center; gap: 36px; }
.main-nav a { font-size: 15px; letter-spacing: .12em; position: relative; padding: 6px 0; opacity: .9; transition: opacity .3s, color .3s; }
.main-nav a::after {
  content: ""; position: absolute; left: 0; bottom: 0; height: 1px; width: 100%;
  background: var(--gold); transform: scaleX(0); transform-origin: right; transition: transform .35s var(--ease);
}
.main-nav a:hover, .main-nav a.is-current { opacity: 1; color: var(--gold-light); }
.main-nav a:hover::after, .main-nav a.is-current::after { transform: scaleX(1); transform-origin: left; }
.main-nav .nav-cta { border: 1px solid var(--gold); padding: 7px 20px; color: var(--gold-light); }
.main-nav .nav-cta::after { display: none; }
.main-nav .nav-cta:hover { background: var(--gold); color: var(--espresso); }

.nav-toggle { display: none; width: 44px; height: 44px; background: none; border: 0; position: relative; }
.nav-toggle span { position: absolute; left: 10px; right: 10px; height: 1.5px; background: #fff; transition: all .3s var(--ease); }
.nav-toggle span:nth-child(1) { top: 15px; }
.nav-toggle span:nth-child(2) { top: 21px; }
.nav-toggle span:nth-child(3) { top: 27px; }
.nav-toggle[aria-expanded="true"] span:nth-child(1) { top: 21px; transform: rotate(45deg); }
.nav-toggle[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] span:nth-child(3) { top: 21px; transform: rotate(-45deg); }

/* ---------- Hero ---------- */
.hero {
  position: relative; min-height: 100vh; min-height: 100svh;
  display: flex; align-items: center; justify-content: center; text-align: center;
  color: #fff; overflow: hidden;
}
.hero-bg {
  position: absolute; inset: -4%; background: center / cover no-repeat;
  animation: heroZoom 18s var(--ease) forwards;
}
@keyframes heroZoom { from { transform: scale(1.12); } to { transform: scale(1); } }
.hero-overlay {
  position: absolute; inset: 0;
  background:
    radial-gradient(ellipse at center, rgba(28,22,18,.45) 0%, rgba(28,22,18,.62) 75%),
    linear-gradient(180deg, rgba(28,22,18,.5) 0%, rgba(28,22,18,.05) 35%, rgba(28,22,18,.75) 100%);
}
.hero-content { position: relative; z-index: 1; padding: 120px 0 100px; }
.hero-content > * { opacity: 0; animation: heroIn 1.2s var(--ease) forwards; }
.hero-content > :nth-child(2) { animation-delay: .15s; }
.hero-content > :nth-child(3) { animation-delay: .35s; }
.hero-content > :nth-child(4) { animation-delay: .5s; }
.hero-content > :nth-child(5) { animation-delay: .65s; }
.hero-content > :nth-child(6) { animation-delay: .85s; }
@keyframes heroIn { from { opacity: 0; transform: translateY(28px); } to { opacity: 1; transform: none; } }
.hero-eyebrow { font-size: 12px; letter-spacing: .45em; color: var(--gold-light); margin-bottom: 28px; }
.hero-title {
  font-size: clamp(34px, 6.4vw, 78px); letter-spacing: .2em; font-weight: 700;
  text-shadow: 0 4px 30px rgba(0,0,0,.35);
  padding-left: .2em; /* 平衡字间距 */
}
.hero-divider { display: flex; align-items: center; justify-content: center; gap: 18px; margin: 30px auto; color: var(--gold); }
.hero-divider span { width: 80px; height: 1px; background: linear-gradient(90deg, transparent, var(--gold)); }
.hero-divider span:last-child { transform: scaleX(-1); }
.hero-divider i { font-style: normal; font-size: 10px; }
.hero-slogan {
  font-family: var(--serif); font-size: clamp(20px, 2.6vw, 32px); letter-spacing: .38em;
  padding-left: .38em; color: var(--gold-light);
}
.hero-slogan em { font-style: normal; color: var(--gold); margin: 0 .2em; }
.hero-slogan--sub { margin-top: 10px; font-size: clamp(16px, 1.8vw, 22px); color: rgba(255,255,255,.85); letter-spacing: .5em; padding-left: .5em; }
.hero-actions { margin-top: 52px; display: flex; gap: 18px; justify-content: center; flex-wrap: wrap; }

.scroll-hint {
  position: absolute; bottom: 32px; left: 50%; transform: translateX(-50%); z-index: 1;
  display: flex; flex-direction: column; align-items: center; gap: 10px;
  font-size: 10px; letter-spacing: .4em; color: rgba(255,255,255,.7);
}
.scroll-hint i { width: 1px; height: 46px; background: rgba(255,255,255,.25); position: relative; overflow: hidden; }
.scroll-hint i::after {
  content: ""; position: absolute; left: 0; top: -50%; width: 100%; height: 50%;
  background: var(--gold-light); animation: scrollLine 2.2s ease-in-out infinite;
}
@keyframes scrollLine { to { top: 100%; } }

/* ---------- 数据条 ---------- */
.intro { background: var(--espresso); color: #fff; border-bottom: 1px solid var(--line); }
.intro-grid { display: grid; grid-template-columns: repeat(4, 1fr); }
.stat { text-align: center; padding: 46px 12px; position: relative; }
.stat + .stat::before { content: ""; position: absolute; left: 0; top: 30%; height: 40%; width: 1px; background: var(--line); }
.stat b { font-family: var(--serif); font-size: clamp(32px, 4vw, 48px); color: var(--gold-light); font-weight: 600; }
.stat span { font-size: 16px; color: var(--gold); margin-left: 4px; }
.stat p { font-size: 14px; letter-spacing: .2em; color: rgba(255,255,255,.65); margin-top: 6px; }

/* ---------- 产品系列 ---------- */
.products { background: var(--ivory); }
.product-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 32px; }
.product-card { background: #fff; overflow: hidden; transition: transform .5s var(--ease), box-shadow .5s var(--ease); }
.product-card:hover { transform: translateY(-8px); box-shadow: 0 30px 60px -25px rgba(43, 33, 27, .35); }
.product-media { position: relative; aspect-ratio: 4 / 3.4; overflow: hidden; background: var(--cream); }
.product-media img { width: 100%; height: 100%; object-fit: cover; object-position: center 60%; transition: transform 1.2s var(--ease); }
.product-card:hover .product-media img { transform: scale(1.06); }
.product-index {
  position: absolute; left: 20px; top: 14px; font-family: var(--serif); font-size: 44px;
  color: #fff; text-shadow: 0 2px 16px rgba(0,0,0,.45); opacity: .9;
}
.product-body { padding: 30px 30px 34px; }
.product-en { font-size: 11px; letter-spacing: .35em; color: var(--gold); }
.product-body h3 { font-size: 24px; letter-spacing: .12em; margin: 6px 0 14px; color: var(--espresso); }
.product-body > p:not(.product-en) { font-size: 14.5px; color: var(--muted); }
.product-tags { list-style: none; padding: 0; margin: 20px 0 0; display: flex; flex-wrap: wrap; gap: 8px; }
.product-tags li { font-size: 12px; padding: 3px 12px; border: 1px solid var(--line); color: var(--oak); letter-spacing: .08em; }

.feature {
  margin-top: 110px; display: grid; grid-template-columns: 1.05fr 1fr; gap: 72px; align-items: center;
}
.feature-media { position: relative; }
.feature-media::before {
  content: ""; position: absolute; inset: 28px -28px -28px 28px; border: 1px solid var(--gold); z-index: 0;
}
.feature-media img { position: relative; z-index: 1; width: 100%; aspect-ratio: 1 / 1; object-fit: cover; box-shadow: 0 30px 60px -30px rgba(0,0,0,.45); }
.feature-text h3 { font-size: clamp(26px, 3vw, 36px); letter-spacing: .08em; color: var(--espresso); margin-bottom: 24px; }
.feature-text > p:not(.eyebrow) { color: var(--muted); }
.spec-list { margin: 34px 0 0; display: grid; grid-template-columns: 1fr 1fr; gap: 0; border-top: 1px solid var(--line); }
.spec-list div { padding: 16px 0; border-bottom: 1px solid var(--line); }
.spec-list dt { font-size: 12px; letter-spacing: .25em; color: var(--gold); }
.spec-list dd { margin: 4px 0 0; font-size: 15px; color: var(--ink); }

/* ---------- 色板 ---------- */
.palette { background: var(--cream); }
.palette-layout { display: grid; grid-template-columns: 1.15fr 1fr; gap: 64px; align-items: start; }
.palette-preview { position: sticky; top: calc(var(--header-h) + 24px); }
.preview-board {
  --c1: #d39a4c; --c2: #b07a33;
  aspect-ratio: 4 / 3; overflow: hidden; position: relative;
  box-shadow: 0 40px 70px -35px rgba(43, 33, 27, .6);
  transform: perspective(1200px) rotateX(8deg); transform-origin: bottom;
}
.preview-planks { position: absolute; inset: 0; display: grid; grid-template-rows: repeat(6, 1fr); gap: 2px; background: rgba(0,0,0,.25); }
.preview-planks span {
  background-image: var(--grain), linear-gradient(90deg, var(--c1), var(--c2) 45%, var(--c1) 70%, var(--c2));
  background-size: 300px 300px, 100% 100%;
  transition: background-color .6s, filter .6s;
  position: relative;
}
.preview-planks span:nth-child(odd) { background-position: 120px 40px, 0 0; filter: brightness(1.04); }
.preview-planks span:nth-child(3n) { background-position: 60px 180px, 0 0; filter: brightness(.95); }
.preview-planks span::after { /* 错缝 */
  content: ""; position: absolute; top: 0; bottom: 0; width: 2px; background: rgba(0,0,0,.22); left: 62%;
}
.preview-planks span:nth-child(even)::after { left: 28%; }
.preview-planks span:nth-child(3n)::after { left: 81%; }
.preview-info { margin-top: 36px; }
.preview-code { font-size: 12px; letter-spacing: .3em; color: var(--gold); }
.preview-info h3 { font-size: 30px; letter-spacing: .14em; color: var(--espresso); margin: 4px 0 10px; }
.preview-info p:last-child { color: var(--muted); min-height: 3.6em; }

.swatch-group { margin-bottom: 30px; }
.swatch-group h4 { font-size: 17px; letter-spacing: .14em; color: var(--espresso); margin-bottom: 14px; }
.swatch-group h4 small { font-family: var(--sans); font-size: 11px; letter-spacing: .25em; color: var(--gold); margin-left: 8px; font-weight: 400; text-transform: uppercase; }
.swatches { display: grid; grid-template-columns: repeat(4, 1fr); gap: 12px; }
.swatch {
  aspect-ratio: 3 / 4; border: 0; padding: 0; position: relative;
  background-image: var(--grain), linear-gradient(160deg, var(--c1), var(--c2));
  background-size: 300px 300px, 100% 100%;
  box-shadow: 0 8px 18px -10px rgba(0,0,0,.45);
  transition: transform .35s var(--ease), box-shadow .35s;
}
.swatch::after {
  content: attr(data-name); position: absolute; left: 0; right: 0; bottom: -26px;
  font-size: 12px; color: var(--muted); letter-spacing: .08em; white-space: nowrap;
}
.swatches { padding-bottom: 26px; }
.swatch:hover { transform: translateY(-4px); }
.swatch.is-active { outline: 2px solid var(--gold); outline-offset: 4px; }
.swatch.is-active::after { color: var(--espresso); font-weight: 600; }
.swatch:focus-visible { outline: 2px solid var(--espresso); outline-offset: 4px; }

.board-photo { margin: 18px 0 0; cursor: zoom-in; }
.board-photo img { width: 100%; aspect-ratio: 16 / 10; object-fit: cover; transition: filter .4s; }
.board-photo:hover img { filter: brightness(1.06); }
.board-photo figcaption { font-size: 12px; color: var(--muted); letter-spacing: .15em; margin-top: 10px; }

/* ---------- 工艺 ---------- */
.craft { color: #fff; overflow: hidden; background: var(--espresso); }
.craft-bg { position: absolute; inset: 0; background: center / cover no-repeat; background-attachment: fixed; }
.craft-overlay { position: absolute; inset: 0; background: linear-gradient(180deg, rgba(20,18,14,.88), rgba(28,22,18,.82) 50%, rgba(28,22,18,.95)); }
.craft-inner { position: relative; }
.process { list-style: none; padding: 0; margin: 0; display: grid; grid-template-columns: repeat(4, 1fr); gap: 0; border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.process li { padding: 44px 30px 46px; position: relative; transition: background .4s; }
.process li + li { border-left: 1px solid var(--line); }
.process li:hover { background: rgba(193,154,98,.07); }
.step-no { position: absolute; right: 24px; top: 22px; font-family: var(--serif); font-size: 40px; color: rgba(193,154,98,.22); }
.process svg { width: 44px; height: 44px; color: var(--gold); margin-bottom: 22px; }
.process h3 { font-size: 20px; letter-spacing: .1em; margin-bottom: 12px; color: var(--gold-light); }
.process p { font-size: 14px; color: rgba(255,255,255,.7); }

.quality-grid { margin-top: 70px; display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; }
.quality { text-align: center; padding: 36px 16px; border: 1px solid var(--line); background: rgba(28,22,18,.4); }
.quality b { display: block; font-family: var(--serif); font-size: 40px; color: var(--gold-light); font-weight: 600; line-height: 1.2; }
.quality b small { font-size: 18px; margin-left: 2px; }
.quality h4 { font-size: 16px; letter-spacing: .2em; margin: 10px 0; }
.quality p { font-size: 13px; color: rgba(255,255,255,.62); line-height: 1.9; }

/* ---------- 场景 ---------- */
.scenes { background: var(--ivory); }
.scene-filter { display: flex; justify-content: center; flex-wrap: wrap; gap: 10px; margin: -24px 0 44px; }
.scene-filter button {
  background: none; border: 1px solid var(--line); padding: 8px 26px; letter-spacing: .2em; font-size: 14px;
  color: var(--oak); transition: all .3s;
}
.scene-filter button:hover { border-color: var(--gold); }
.scene-filter button.is-active { background: var(--espresso); border-color: var(--espresso); color: var(--gold-light); }

.scene-grid { display: grid; grid-template-columns: repeat(3, 1fr); grid-auto-rows: 300px; gap: 16px; grid-auto-flow: dense; }
.scene { margin: 0; position: relative; overflow: hidden; cursor: zoom-in; background: var(--cream); }
.scene--wide { grid-column: span 2; }
.scene--tall { grid-row: span 2; }
.scene img { width: 100%; height: 100%; object-fit: cover; transition: transform 1.2s var(--ease); }
.scene:hover img { transform: scale(1.06); }
.scene figcaption {
  position: absolute; inset: auto 0 0; padding: 60px 26px 22px; color: #fff;
  background: linear-gradient(transparent, rgba(20,16,12,.82));
  display: flex; flex-direction: column; gap: 2px;
}
.scene figcaption span { font-size: 11px; letter-spacing: .3em; color: var(--gold-light); }
.scene figcaption b { font-family: var(--serif); font-size: 19px; letter-spacing: .1em; font-weight: 600; }
.scene.is-hidden { display: none; }

/* ---------- 关于 ---------- */
.about { background: #fff; }
.about-grid { display: grid; grid-template-columns: 1fr 1.05fr; gap: 80px; align-items: center; }
.about-media { position: relative; }
.about-media img { width: 100%; aspect-ratio: 4 / 4.6; object-fit: cover; }
.about-badge {
  position: absolute; right: -28px; bottom: 40px; background: var(--espresso); color: #fff;
  padding: 26px 30px; text-align: center; box-shadow: 0 20px 40px -20px rgba(0,0,0,.5);
}
.about-badge b { display: block; font-family: var(--serif); font-size: 38px; color: var(--gold-light); line-height: 1.1; }
.about-badge span { font-size: 12px; letter-spacing: .3em; color: rgba(255,255,255,.7); }
.about-text h2 { font-size: clamp(30px, 4vw, 42px); letter-spacing: .12em; color: var(--espresso); }
.about-text .lead { font-family: var(--serif); font-size: 21px; color: var(--oak); letter-spacing: .15em; margin: 18px 0 22px; }
.about-text > p:not(.eyebrow):not(.lead) { color: var(--muted); margin-bottom: 14px; font-size: 15.5px; }
.values { list-style: none; padding: 0; margin: 34px 0 0; display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; }
.values li { display: flex; align-items: center; gap: 14px; }
.values b {
  width: 54px; height: 54px; flex-shrink: 0; border: 1px solid var(--gold); border-radius: 50%;
  display: grid; place-items: center; font-family: var(--serif); font-size: 22px; color: var(--oak);
}
.values span { font-size: 15px; line-height: 1.5; color: var(--espresso); font-family: var(--serif); }
.values small { font-family: var(--sans); font-size: 12px; color: var(--muted); }

.timeline { margin-top: 100px; display: grid; grid-template-columns: repeat(4, 1fr); position: relative; }
.timeline::before { content: ""; position: absolute; left: 0; right: 0; top: 9px; height: 1px; background: var(--line); }
.tl-item { position: relative; padding: 34px 20px 0 0; }
.tl-item::before {
  content: ""; position: absolute; left: 0; top: 4px; width: 11px; height: 11px; border-radius: 50%;
  background: #fff; border: 1px solid var(--gold);
}
.tl-item b { font-family: var(--serif); font-size: 26px; color: var(--oak); }
.tl-item p { font-size: 14px; color: var(--muted); margin-top: 4px; }

/* ---------- 联系 ---------- */
.contact { color: #fff; overflow: hidden; background: var(--walnut); }
.contact-bg { position: absolute; inset: 0; background: center / cover no-repeat; }
.contact-overlay { position: absolute; inset: 0; background: rgba(24,18,14,.82); }
.contact-inner { position: relative; }
.contact-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 22px; }
.contact-card {
  padding: 40px 28px; border: 1px solid var(--line); background: rgba(28,22,18,.55);
  transition: border-color .4s, transform .4s var(--ease);
}
.contact-card:hover { border-color: var(--gold); transform: translateY(-4px); }
.contact-card svg { width: 30px; height: 30px; color: var(--gold); margin-bottom: 22px; }
.contact-card h3 { font-size: 15px; letter-spacing: .3em; color: rgba(255,255,255,.7); font-weight: 400; font-family: var(--sans); }
.contact-main { font-family: var(--serif); font-size: 20px; color: var(--gold-light); margin: 10px 0 6px; word-break: break-all; }
.contact-card p:last-child { font-size: 13px; color: rgba(255,255,255,.55); }
.contact-note { text-align: center; margin-top: 40px; font-size: 12px; color: rgba(255,255,255,.4); letter-spacing: .15em; }

/* ---------- 页脚 ---------- */
.site-footer { background: var(--espresso); color: rgba(255,255,255,.6); padding: 56px 0 36px; border-top: 1px solid var(--line); }
.footer-inner { display: grid; grid-template-columns: 1fr auto; gap: 24px 40px; align-items: center; }
.footer-brand strong { font-family: var(--serif); font-size: 20px; letter-spacing: .2em; color: #fff; font-weight: 600; }
.footer-brand p { font-size: 13px; color: var(--gold); letter-spacing: .2em; margin-top: 6px; }
.footer-nav { display: flex; gap: 28px; flex-wrap: wrap; font-size: 14px; letter-spacing: .1em; }
.footer-nav a:hover { color: var(--gold-light); }
.copyright { grid-column: 1 / -1; font-size: 12px; padding-top: 24px; border-top: 1px solid rgba(255,255,255,.08); letter-spacing: .05em; }

.back-top {
  position: fixed; right: 24px; bottom: 24px; z-index: 90; width: 46px; height: 46px;
  display: grid; place-items: center; background: var(--espresso); color: var(--gold-light);
  border: 1px solid var(--gold); font-size: 18px;
  opacity: 0; visibility: hidden; transform: translateY(10px); transition: all .4s var(--ease);
}
.back-top.is-visible { opacity: 1; visibility: visible; transform: none; }
.back-top:hover { background: var(--gold); color: var(--espresso); }

/* ---------- 灯箱 ---------- */
.lightbox {
  position: fixed; inset: 0; z-index: 200; background: rgba(14,11,9,.94);
  display: grid; place-items: center; padding: 40px;
  opacity: 0; visibility: hidden; transition: opacity .35s, visibility .35s;
}
.lightbox.is-open { opacity: 1; visibility: visible; }
.lightbox img { max-width: 100%; max-height: 88vh; object-fit: contain; box-shadow: 0 30px 80px rgba(0,0,0,.6); }
.lightbox-close {
  position: absolute; top: 18px; right: 22px; width: 48px; height: 48px; background: none;
  border: 1px solid var(--line); color: var(--gold-light); font-size: 28px; line-height: 1;
}

/* ---------- 滚动显现 ---------- */
.reveal { opacity: 0; transform: translateY(32px); transition: opacity 1s var(--ease), transform 1s var(--ease); }
.reveal.is-in { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; transition: none; }
  .hero-bg, .scroll-hint i::after { animation: none; }
  .hero-content > * { animation: none; opacity: 1; }
}

/* =========================================================
   响应式
   ========================================================= */
@media (max-width: 1080px) {
  .main-nav { gap: 24px; }
  .product-grid { gap: 22px; }
  .product-body { padding: 24px; }
  .feature { gap: 56px; }
  .process { grid-template-columns: repeat(2, 1fr); }
  .process li:nth-child(3) { border-left: 0; }
  .process li:nth-child(n+3) { border-top: 1px solid var(--line); }
  .quality-grid, .contact-grid { grid-template-columns: repeat(2, 1fr); }
  .about-grid { gap: 56px; }
  .craft-bg { background-attachment: scroll; }
}

@media (max-width: 900px) {
  :root { --header-h: 64px; }
  .nav-toggle { display: block; }
  /* backdrop-filter 会让 fixed 子元素相对 header 定位，移动端关闭 */
  .site-header.is-scrolled { backdrop-filter: none; -webkit-backdrop-filter: none; background: rgba(28,22,18,.97); }
  .main-nav {
    position: fixed; inset: 0; z-index: -1;
    background: rgba(24,18,14,.98);
    flex-direction: column; justify-content: center; gap: 30px;
    opacity: 0; visibility: hidden; transition: opacity .4s var(--ease), visibility .4s;
  }
  .main-nav a { font-family: var(--serif); font-size: 22px; letter-spacing: .3em; }
  .main-nav.is-open { opacity: 1; visibility: visible; }
  .section { padding: 88px 0; }
  .section-head { margin-bottom: 48px; }
  .product-grid { grid-template-columns: 1fr; max-width: 560px; margin-inline: auto; }
  .feature { grid-template-columns: 1fr; margin-top: 80px; gap: 56px; }
  .feature-media { margin-right: 28px; }
  .palette-layout { grid-template-columns: 1fr; gap: 48px; }
  .palette-preview { position: static; }
  .scene-grid { grid-template-columns: repeat(2, 1fr); grid-auto-rows: 240px; }
  .about-grid { grid-template-columns: 1fr; }
  .about-media { margin-right: 28px; }
  .footer-inner { grid-template-columns: 1fr; }
}

@media (max-width: 600px) {
  .container { width: calc(100% - 36px); }
  .logo-text strong { font-size: 17px; }
  .logo-mark { width: 36px; height: 36px; }
  .hero-title { letter-spacing: .1em; padding-left: .1em; font-size: clamp(30px, 8.6vw, 44px); }
  .hero-slogan { letter-spacing: .22em; padding-left: .22em; }
  .hero-slogan--sub { letter-spacing: .3em; padding-left: .3em; }
  .hero-eyebrow { font-size: 10px; letter-spacing: .25em; }
  .hero-actions .btn { width: 100%; max-width: 280px; }
  .intro-grid { grid-template-columns: repeat(2, 1fr); }
  .stat { padding: 32px 8px; }
  .stat:nth-child(3)::before { display: none; }
  .stat:nth-child(n+3) { border-top: 1px solid var(--line); }
  .section { padding: 72px 0; }
  .spec-list { grid-template-columns: 1fr; }
  .process { grid-template-columns: 1fr; }
  .process li + li { border-left: 0; border-top: 1px solid var(--line); }
  .process li { padding: 34px 8px; }
  .quality-grid { gap: 12px; }
  .quality { padding: 26px 10px; }
  .quality b { font-size: 30px; }
  .contact-grid { grid-template-columns: 1fr; }
  .scene-grid { grid-template-columns: 1fr; grid-auto-rows: 260px; }
  .scene--wide { grid-column: auto; }
  .scene--tall { grid-row: span 1; }
  .scene-filter button { padding: 6px 16px; }
  .swatches { gap: 10px; }
  .swatch::after { font-size: 11px; }
  .values { grid-template-columns: 1fr; }
  .about-badge { right: -18px; padding: 18px 22px; }
  .about-badge b { font-size: 30px; }
  .timeline { grid-template-columns: 1fr 1fr; row-gap: 36px; margin-top: 72px; }
  .timeline::before { display: none; }
  .tl-item { border-top: 1px solid var(--line); }
  .tl-item::before { top: -6px; }
}