/* ============================================================
   MCGW · 机械动力服务器官网
   主题：黄铜 / 蒸汽朋克 / 工业蓝图
   ============================================================ */

/* ---------- 变量 ---------- */
:root {
  /* 配色 - 深棕底 + 黄铜金 + 铜色 + 余烬橙 */
  --bg-deep: #0d0904;
  --bg: #150e07;
  --bg-soft: #1f160a;
  --bg-card: #241a0e;
  --bg-card-hi: #2c2012;

  --brass: #c9a14a;
  --brass-bright: #e8c878;
  --brass-dim: #8a6f33;
  --copper: #b87333;
  --copper-dark: #8a5a26;
  --ember: #d4622a;
  --ember-glow: #e8743a;

  --text: #f5e6d3;
  --text-dim: #b8a890;
  --text-faint: #6b5d47;
  --line: #3a2c1a;
  --line-soft: #2a2017;

  /* 字体 */
  --font-display: 'Cinzel', 'Noto Serif SC', serif;
  --font-serif: 'Noto Serif SC', serif;
  --font-sans: 'Noto Sans SC', system-ui, sans-serif;
  --font-mono: 'JetBrains Mono', monospace;

  /* 尺寸 */
  --container: 1180px;
  --container-narrow: 820px;
  --radius: 14px;
  --radius-sm: 8px;

  /* 阴影 */
  --shadow-card: 0 18px 40px -18px rgba(0,0,0,.7), 0 2px 0 rgba(201,161,74,.08) inset;
  --glow-brass: 0 0 24px rgba(201,161,74,.35);
}

/* ---------- 重置 ---------- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  font-family: var(--font-sans);
  background: var(--bg-deep);
  color: var(--text);
  line-height: 1.7;
  font-weight: 300;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
img, svg { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; }
button { font: inherit; color: inherit; background: none; border: none; cursor: pointer; }
ul { list-style: none; }

::selection { background: var(--brass); color: var(--bg-deep); }

/* ---------- 滚动条 ---------- */
::-webkit-scrollbar { width: 10px; }
::-webkit-scrollbar-track { background: var(--bg-deep); }
::-webkit-scrollbar-thumb { background: var(--copper-dark); border-radius: 5px; border: 2px solid var(--bg-deep); }
::-webkit-scrollbar-thumb:hover { background: var(--copper); }

/* ---------- 容器 ---------- */
.container { width: 100%; max-width: var(--container); margin: 0 auto; padding: 0 28px; }
.container--narrow { max-width: var(--container-narrow); }

/* ---------- SVG 符号库隐藏 ---------- */
.svg-defs { position: absolute; width: 0; height: 0; overflow: hidden; }

/* ---------- 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 14px 28px;
  border-radius: var(--radius-sm);
  font-family: var(--font-sans);
  font-weight: 600;
  font-size: 15px;
  letter-spacing: .04em;
  position: relative;
  transition: transform .25s ease, box-shadow .25s ease, background .25s ease, color .25s ease;
  white-space: nowrap;
}
.btn__icon { width: 18px; height: 18px; fill: currentColor; }
.btn--small { padding: 10px 18px; font-size: 13px; }

.btn--primary {
  background: linear-gradient(135deg, var(--copper) 0%, var(--brass) 100%);
  color: var(--bg-deep);
  box-shadow: 0 8px 22px -8px rgba(201,161,74,.6), 0 1px 0 rgba(255,255,255,.25) inset;
}
.btn--primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 14px 30px -10px rgba(201,161,74,.75), 0 1px 0 rgba(255,255,255,.3) inset;
}

.btn--ghost {
  background: transparent;
  color: var(--brass-bright);
  border: 1.5px solid var(--copper-dark);
}
.btn--ghost:hover {
  background: rgba(184,115,51,.12);
  border-color: var(--brass);
  color: var(--text);
  transform: translateY(-2px);
}

/* ============================================================
   导航
   ============================================================ */
.nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  padding: 18px 0;
  transition: background .35s ease, padding .35s ease, border-color .35s ease;
  border-bottom: 1px solid transparent;
}
.nav.scrolled {
  background: rgba(13,9,4,.85);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  padding: 12px 0;
  border-bottom-color: var(--line-soft);
}
.nav__inner {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 28px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}
.nav__logo {
  display: flex;
  align-items: center;
  gap: 12px;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 22px;
  letter-spacing: .12em;
  color: var(--brass-bright);
}
.nav__logo-gear {
  width: 30px; height: 30px;
  color: var(--brass);
  animation: spin 12s linear infinite;
}
.nav__links {
  display: flex;
  gap: 32px;
  font-size: 14px;
  font-weight: 400;
  letter-spacing: .05em;
  color: var(--text-dim);
}
.nav__links a {
  position: relative;
  padding: 6px 0;
  transition: color .25s ease;
}
.nav__links a::after {
  content: '';
  position: absolute;
  left: 0; bottom: 0;
  width: 0; height: 1.5px;
  background: var(--brass);
  transition: width .3s ease;
}
.nav__links a:hover { color: var(--text); }
.nav__links a:hover::after { width: 100%; }
.nav__cta { flex-shrink: 0; }

.nav__burger {
  display: none;
  flex-direction: column;
  gap: 5px;
  padding: 8px;
}
.nav__burger span {
  width: 24px; height: 2px;
  background: var(--text);
  transition: transform .3s ease, opacity .3s ease;
}
.nav__burger.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav__burger.open span:nth-child(2) { opacity: 0; }
.nav__burger.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ============================================================
   Hero
   ============================================================ */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 120px 28px 80px;
  overflow: hidden;
  background:
    radial-gradient(ellipse 90% 70% at 50% 42%, #1e1508 0%, #130c05 45%, var(--bg-deep) 100%);
}

/* 背景光晕层 */
.hero__bg {
  position: absolute;
  inset: 0;
  pointer-events: none;
  z-index: 0;
}
.hero__glow {
  position: absolute;
  border-radius: 50%;
  filter: blur(90px);
}
.hero__glow--center {
  width: 75vw; height: 75vw;
  max-width: 920px; max-height: 920px;
  top: 50%; left: 50%;
  transform: translate(-50%, -50%);
  background: radial-gradient(circle, rgba(201,161,74,.28) 0%, rgba(184,115,51,.12) 35%, transparent 65%);
  animation: breathe 9s ease-in-out infinite;
}
.hero__glow--top {
  width: 70vw; height: 45vh;
  top: -22%; left: 50%;
  transform: translateX(-50%);
  background: radial-gradient(ellipse, rgba(212,98,42,.2) 0%, transparent 70%);
}
.hero__glow--bottom {
  width: 85vw; height: 38vh;
  bottom: -18%; left: 50%;
  transform: translateX(-50%);
  background: radial-gradient(ellipse, rgba(184,115,51,.16) 0%, transparent 70%);
}
@keyframes breathe {
  0%, 100% { opacity: .55; transform: translate(-50%, -50%) scale(1); }
  50% { opacity: .8; transform: translate(-50%, -50%) scale(1.06); }
}

/* 暗角 - 聚焦中心 */
.hero__vignette {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 100% 85% at 50% 50%, transparent 38%, rgba(0,0,0,.45) 88%, rgba(0,0,0,.72) 100%);
  pointer-events: none;
}

/* 背景纹理 - 精密蓝图网格（双层疏密） */
.hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(201,161,74,.05) 1px, transparent 1px),
    linear-gradient(90deg, rgba(201,161,74,.05) 1px, transparent 1px),
    linear-gradient(rgba(201,161,74,.022) 1px, transparent 1px),
    linear-gradient(90deg, rgba(201,161,74,.022) 1px, transparent 1px);
  background-size: 84px 84px, 84px 84px, 14px 14px, 14px 14px;
  mask-image: radial-gradient(ellipse 78% 78% at 50% 50%, #000 0%, transparent 88%);
  -webkit-mask-image: radial-gradient(ellipse 78% 78% at 50% 50%, #000 0%, transparent 88%);
  pointer-events: none;
  z-index: 0;
}

/* 背景齿轮（描边蓝图风，带发光） */
.hero__gears {
  position: absolute;
  inset: 0;
  pointer-events: none;
  z-index: 1;
}
.gear {
  position: absolute;
  filter: drop-shadow(0 0 10px rgba(201,161,74,.28));
}
.gear--xl { width: 360px; height: 360px; color: var(--brass-dim); opacity: .55; }
.gear--lg { width: 280px; height: 280px; color: var(--copper); opacity: .52; }
.gear--md { width: 200px; height: 200px; color: var(--brass); opacity: .48; }
.gear--sm { width: 140px; height: 140px; color: var(--brass-bright); opacity: .42; }

@keyframes spin {
  from { transform: rotate(0deg); }
  to { transform: rotate(360deg); }
}
@keyframes spin-rev {
  from { transform: rotate(0deg); }
  to { transform: rotate(-360deg); }
}
.gear--spin-slow { animation: spin 60s linear infinite; }
.gear--spin-rev  { animation: spin-rev 45s linear infinite; }
.gear--spin-med  { animation: spin 30s linear infinite; }
.gear--spin-fast { animation: spin 18s linear infinite; }

/* 金色光尘 canvas */
.hero__steam {
  position: absolute;
  inset: 0;
  width: 100%; height: 100%;
  pointer-events: none;
  z-index: 1;
}

/* Hero 内容 */
.hero__content {
  position: relative;
  z-index: 2;
  max-width: 880px;
}
.hero__tag {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 8px 18px;
  border: 1px solid var(--copper-dark);
  border-radius: 100px;
  background: rgba(36,26,14,.6);
  backdrop-filter: blur(8px);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .15em;
  color: var(--brass-bright);
  margin-bottom: 36px;
}
.hero__tag-dot {
  width: 8px; height: 8px;
  border-radius: 50%;
  background: var(--ember-glow);
  box-shadow: 0 0 12px var(--ember-glow);
  animation: pulse 2s ease-in-out infinite;
}
@keyframes pulse {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: .5; transform: scale(1.3); }
}

.hero__title {
  font-family: var(--font-display);
  margin-bottom: 28px;
  line-height: 1;
}
.hero__title-main {
  display: block;
  font-size: clamp(72px, 14vw, 160px);
  font-weight: 800;
  letter-spacing: .08em;
  background: linear-gradient(180deg, #f5e6d3 0%, var(--brass-bright) 40%, var(--copper) 100%);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  text-shadow: 0 4px 40px rgba(201,161,74,.3);
  filter: drop-shadow(0 2px 0 rgba(0,0,0,.4));
}
.hero__title-sub {
  display: block;
  font-family: var(--font-serif);
  font-size: clamp(18px, 3vw, 28px);
  font-weight: 500;
  letter-spacing: .6em;
  color: var(--text-dim);
  margin-top: 12px;
  padding-left: .6em;
}

.hero__desc {
  font-size: clamp(15px, 1.6vw, 18px);
  color: var(--text-dim);
  max-width: 620px;
  margin: 0 auto 44px;
  line-height: 1.9;
}

.hero__domain {
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
  margin-bottom: 44px;
}
.hero__domain-label {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .3em;
  color: var(--text-faint);
  text-transform: uppercase;
}
.hero__domain-value {
  display: inline-flex;
  align-items: center;
  gap: 16px;
  padding: 14px 28px;
  background: linear-gradient(135deg, rgba(36,26,14,.9), rgba(21,14,7,.9));
  border: 1.5px solid var(--copper-dark);
  border-radius: var(--radius);
  font-family: var(--font-mono);
  font-size: clamp(16px, 2.4vw, 22px);
  font-weight: 600;
  color: var(--brass-bright);
  letter-spacing: .05em;
  transition: all .25s ease;
  box-shadow: 0 0 0 1px rgba(201,161,74,.1), 0 8px 24px -8px rgba(0,0,0,.5);
}
.hero__domain-value:hover {
  border-color: var(--brass);
  background: linear-gradient(135deg, rgba(46,34,18,.95), rgba(28,19,10,.95));
  transform: translateY(-2px);
  box-shadow: 0 0 0 1px var(--brass-dim), 0 12px 30px -10px rgba(201,161,74,.4);
}
.hero__domain-copy {
  font-family: var(--font-sans);
  font-size: 12px;
  font-weight: 400;
  color: var(--text-faint);
  padding-left: 16px;
  border-left: 1px solid var(--line);
  letter-spacing: .05em;
  transition: color .25s ease;
}
.hero__domain-value:hover .hero__domain-copy { color: var(--brass); }
.hero__domain-value.copied .hero__domain-copy { color: var(--ember-glow); }

.hero__actions {
  display: flex;
  gap: 16px;
  justify-content: center;
  flex-wrap: wrap;
}

/* 滚动提示 */
.hero__scroll {
  position: absolute;
  bottom: 32px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
  z-index: 2;
}
.hero__scroll-text {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: .4em;
  color: var(--text-faint);
  writing-mode: vertical-rl;
}
.hero__scroll-line {
  width: 1px;
  height: 50px;
  background: linear-gradient(180deg, var(--copper) 0%, transparent 100%);
  position: relative;
  overflow: hidden;
}
.hero__scroll-line::after {
  content: '';
  position: absolute;
  top: 0; left: 0;
  width: 100%; height: 30%;
  background: var(--brass-bright);
  animation: scrollDown 2s ease-in-out infinite;
}
@keyframes scrollDown {
  0% { top: -30%; opacity: 0; }
  30% { opacity: 1; }
  100% { top: 100%; opacity: 0; }
}

/* ============================================================
   通用 Section
   ============================================================ */
.section {
  position: relative;
  padding: 120px 0;
}
.section__head {
  display: flex;
  align-items: center;
  gap: 20px;
  margin-bottom: 64px;
}
.section__index {
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 600;
  color: var(--copper);
  letter-spacing: .15em;
  padding: 4px 12px;
  border: 1px solid var(--copper-dark);
  border-radius: 4px;
  background: rgba(184,115,51,.08);
}
.section__title {
  font-family: var(--font-display);
  font-size: clamp(28px, 4vw, 42px);
  font-weight: 700;
  letter-spacing: .05em;
  color: var(--text);
}
.section__line {
  flex: 1;
  height: 1px;
  background: linear-gradient(90deg, var(--copper-dark) 0%, transparent 100%);
}

/* ============================================================
   About
   ============================================================ */
.about { background: var(--bg); }
.about__grid {
  display: grid;
  grid-template-columns: 1.1fr 1fr;
  gap: 72px;
  align-items: center;
}
.about__lead {
  font-family: var(--font-serif);
  font-size: clamp(22px, 2.8vw, 30px);
  font-weight: 500;
  line-height: 1.5;
  color: var(--text);
  margin-bottom: 24px;
}
.hl {
  color: var(--brass-bright);
  position: relative;
  white-space: nowrap;
}
.hl::after {
  content: '';
  position: absolute;
  left: 0; bottom: -2px;
  width: 100%; height: 2px;
  background: linear-gradient(90deg, var(--copper), transparent);
}
.about__text p { color: var(--text-dim); margin-bottom: 18px; font-size: 15.5px; }

.about__stats {
  display: flex;
  gap: 40px;
  margin-top: 40px;
  flex-wrap: wrap;
}
.about__stats li {
  display: flex;
  flex-direction: column;
  gap: 4px;
}
.about__stat-num {
  font-family: var(--font-display);
  font-size: clamp(28px, 3.5vw, 40px);
  font-weight: 700;
  color: var(--brass-bright);
  line-height: 1;
}
.about__stat-label {
  font-size: 12px;
  color: var(--text-faint);
  letter-spacing: .05em;
}

/* 蓝图视觉 */
.about__visual { display: flex; justify-content: center; }
.blueprint {
  position: relative;
  width: 100%;
  max-width: 420px;
  aspect-ratio: 1;
  background: linear-gradient(135deg, #0f1a14 0%, #0a1410 100%);
  border: 1px solid var(--copper-dark);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow-card);
}
.blueprint__grid {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(184,115,51,.12) 1px, transparent 1px),
    linear-gradient(90deg, rgba(184,115,51,.12) 1px, transparent 1px);
  background-size: 24px 24px;
}
.blueprint__art {
  position: absolute;
  inset: 0;
  width: 100%; height: 100%;
  color: var(--brass);
  fill: var(--brass);
  stroke: var(--brass);
}
.blueprint__gear-1 {
  transform-origin: 140px 150px;
  animation: spin 24s linear infinite;
  opacity: .85;
}
.blueprint__gear-2 {
  transform-origin: 100px 100px;
  animation: spin-rev 16s linear infinite;
  opacity: .7;
}
.blueprint__label {
  position: absolute;
  bottom: 16px; left: 16px;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: .2em;
  color: var(--brass-dim);
  padding: 4px 10px;
  border: 1px solid var(--copper-dark);
  border-radius: 3px;
  background: rgba(13,9,4,.6);
}

/* ============================================================
   Features
   ============================================================ */
.features { background: var(--bg-deep); }
.features__grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}
.feature {
  position: relative;
  padding: 36px 28px;
  background: linear-gradient(160deg, var(--bg-card) 0%, var(--bg-soft) 100%);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
  transition: transform .35s ease, border-color .35s ease, box-shadow .35s ease;
}
.feature::before {
  content: '';
  position: absolute;
  top: 0; left: 0;
  width: 100%; height: 3px;
  background: linear-gradient(90deg, transparent, var(--copper), transparent);
  opacity: 0;
  transition: opacity .35s ease;
}
.feature::after {
  content: '';
  position: absolute;
  top: -50%; right: -50%;
  width: 200%; height: 200%;
  background: radial-gradient(circle, rgba(201,161,74,.06) 0%, transparent 50%);
  opacity: 0;
  transition: opacity .5s ease;
  pointer-events: none;
}
.feature:hover {
  transform: translateY(-6px);
  border-color: var(--copper-dark);
  box-shadow: 0 20px 40px -16px rgba(0,0,0,.6);
}
.feature:hover::before { opacity: 1; }
.feature:hover::after { opacity: 1; }

.feature__icon {
  width: 52px; height: 52px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 24px;
  border-radius: 12px;
  background: linear-gradient(135deg, rgba(184,115,51,.15), rgba(201,161,74,.08));
  border: 1px solid var(--copper-dark);
  color: var(--brass-bright);
}
.feature__icon svg { width: 28px; height: 28px; }
.feature:hover .feature__icon { animation: spin 4s linear infinite; }
.feature__title {
  font-family: var(--font-serif);
  font-size: 19px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 12px;
  letter-spacing: .02em;
}
.feature__desc {
  font-size: 14px;
  color: var(--text-dim);
  line-height: 1.8;
}

/* ============================================================
   Team
   ============================================================ */
.team { background: var(--bg); }
.team__intro {
  text-align: center;
  font-family: var(--font-serif);
  font-size: clamp(16px, 2vw, 20px);
  color: var(--text-dim);
  margin-bottom: 64px;
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}
.team__grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 28px;
  max-width: 1000px;
  margin: 0 auto;
}

/* 腐竹卡片跨两列 */
.member--owner { grid-column: span 2; }
@media (max-width: 640px) {
  .member--owner { grid-column: span 1; }
}

.member {
  position: relative;
  padding: 36px 28px;
  background: linear-gradient(170deg, var(--bg-card) 0%, var(--bg-soft) 100%);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  text-align: center;
  transition: transform .35s ease, border-color .35s ease, box-shadow .35s ease;
  overflow: hidden;
}
.member::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 80px;
  background: radial-gradient(ellipse at 50% 0%, rgba(184,115,51,.18) 0%, transparent 70%);
  pointer-events: none;
}
.member:hover {
  transform: translateY(-6px);
  border-color: var(--copper-dark);
  box-shadow: 0 20px 40px -16px rgba(0,0,0,.6);
}

.member--owner {
  background: linear-gradient(170deg, #2a1d0e 0%, var(--bg-soft) 100%);
  border-color: var(--copper-dark);
}
.member--owner::before {
  background: radial-gradient(ellipse at 50% 0%, rgba(201,161,74,.25) 0%, transparent 70%);
}

.member__avatar {
  position: relative;
  width: 110px; height: 110px;
  margin: 0 auto 24px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  background: radial-gradient(circle, var(--bg-deep) 55%, transparent 56%);
}
.member__avatar-gear {
  position: absolute;
  inset: 0;
  width: 100%; height: 100%;
  color: var(--copper);
  animation: spin 20s linear infinite;
}
.member--owner .member__avatar-gear {
  color: var(--brass);
  animation-duration: 14s;
}
.member__avatar-text {
  position: relative;
  z-index: 2;
  font-family: var(--font-display);
  font-size: 22px;
  font-weight: 800;
  color: var(--brass-bright);
  letter-spacing: .05em;
  text-transform: uppercase;
}
.member__role {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: .15em;
  color: var(--copper);
  padding: 4px 12px;
  border: 1px solid var(--copper-dark);
  border-radius: 100px;
  margin-bottom: 14px;
  background: rgba(184,115,51,.08);
}
.member__role--owner {
  color: var(--ember-glow);
  border-color: var(--ember);
  background: rgba(212,98,42,.12);
  box-shadow: 0 0 16px rgba(212,98,42,.2);
}
.member__name {
  font-family: var(--font-display);
  font-size: 24px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 10px;
  letter-spacing: .03em;
}
.member__desc {
  font-size: 13.5px;
  color: var(--text-dim);
  line-height: 1.7;
}

/* ============================================================
   Join
   ============================================================ */
.join { background: var(--bg-deep); }
.join__steps {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 32px;
  margin-bottom: 64px;
}
.step {
  position: relative;
  padding: 40px 32px;
  background: linear-gradient(180deg, var(--bg-card) 0%, var(--bg-soft) 100%);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}
.step:not(:last-child)::after {
  content: '';
  position: absolute;
  top: 50%; right: -22px;
  width: 12px; height: 12px;
  border-top: 2px solid var(--copper);
  border-right: 2px solid var(--copper);
  transform: translateY(-50%) rotate(45deg);
  z-index: 2;
}
.step__num {
  font-family: var(--font-display);
  font-size: 56px;
  font-weight: 800;
  line-height: 1;
  color: transparent;
  -webkit-text-stroke: 1.5px var(--copper);
  margin-bottom: 20px;
  letter-spacing: .02em;
}
.step__title {
  font-family: var(--font-serif);
  font-size: 20px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 12px;
}
.step__desc {
  font-size: 14px;
  color: var(--text-dim);
  line-height: 1.8;
}
.step__download {
  margin-top: 22px;
}

/* 下载按钮：图标悬浮微动效 */
.btn--download .btn__icon {
  transition: transform .3s ease;
}
.btn--download:hover .btn__icon {
  animation: bobDown .7s ease-in-out infinite;
}
@keyframes bobDown {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(2px); }
}
.step__desc strong { color: var(--brass-bright); font-weight: 600; }

.join__ip {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  flex-wrap: wrap;
  padding: 32px 40px;
  background: linear-gradient(135deg, rgba(36,26,14,.9), rgba(21,14,7,.9));
  border: 1.5px solid var(--copper-dark);
  border-radius: var(--radius);
  box-shadow: 0 0 0 1px rgba(201,161,74,.1), 0 12px 40px -12px rgba(0,0,0,.5);
}
.join__ip-label {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .3em;
  color: var(--text-faint);
  text-transform: uppercase;
  margin-bottom: 6px;
}
.join__ip-value {
  display: flex;
  align-items: center;
  gap: 24px;
  flex-wrap: wrap;
}
.join__ip-text {
  font-family: var(--font-mono);
  font-size: clamp(20px, 3vw, 28px);
  font-weight: 600;
  color: var(--brass-bright);
  letter-spacing: .04em;
}

.join__cta {
  text-align: center;
  margin-top: 48px;
}

/* ============================================================
   FAQ
   ============================================================ */
.faq { background: var(--bg); }
.faq__list {
  display: flex;
  flex-direction: column;
  gap: 14px;
}
.faq__item {
  background: var(--bg-card);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  overflow: hidden;
  transition: border-color .25s ease, background .25s ease;
}
.faq__item[open] {
  border-color: var(--copper-dark);
  background: var(--bg-card-hi);
}
.faq__item summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 22px 26px;
  cursor: pointer;
  list-style: none;
  font-family: var(--font-serif);
  font-size: 17px;
  font-weight: 500;
  color: var(--text);
  transition: color .25s ease;
}
.faq__item summary::-webkit-details-marker { display: none; }
.faq__item summary:hover { color: var(--brass-bright); }
.faq__icon {
  position: relative;
  width: 18px; height: 18px;
  flex-shrink: 0;
}
.faq__icon::before, .faq__icon::after {
  content: '';
  position: absolute;
  top: 50%; left: 50%;
  background: var(--copper);
  transition: transform .3s ease, background .3s ease;
}
.faq__icon::before { width: 14px; height: 2px; transform: translate(-50%, -50%); }
.faq__icon::after  { width: 2px; height: 14px; transform: translate(-50%, -50%); }
.faq__item[open] .faq__icon::after { transform: translate(-50%, -50%) rotate(90deg); opacity: 0; }
.faq__item[open] .faq__icon::before { background: var(--brass-bright); }

.faq__answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height .35s ease;
}
.faq__item[open] .faq__answer { max-height: 300px; }
.faq__answer p {
  padding: 0 26px 24px;
  font-size: 14.5px;
  color: var(--text-dim);
  line-height: 1.8;
}

/* ============================================================
   Footer
   ============================================================ */
.footer {
  background: var(--bg-deep);
  border-top: 1px solid var(--line-soft);
  padding-top: 64px;
}
.footer__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 32px;
  flex-wrap: wrap;
  padding-bottom: 48px;
}
.footer__brand {
  display: flex;
  align-items: center;
  gap: 14px;
}
.footer__logo {
  width: 36px; height: 36px;
  color: var(--brass);
  animation: spin 16s linear infinite;
}
.footer__name {
  font-family: var(--font-display);
  font-size: 22px;
  font-weight: 800;
  letter-spacing: .12em;
  color: var(--brass-bright);
}
.footer__sub {
  font-size: 12px;
  color: var(--text-faint);
  letter-spacing: .1em;
}
.footer__links {
  display: flex;
  gap: 28px;
  font-size: 14px;
  color: var(--text-dim);
}
.footer__links a {
  transition: color .25s ease;
  position: relative;
}
.footer__links a:hover { color: var(--brass-bright); }
.footer__domain {
  text-align: right;
}
.footer__domain-label {
  display: block;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: .3em;
  color: var(--text-faint);
  margin-bottom: 4px;
}
.footer__domain-value {
  font-family: var(--font-mono);
  font-size: 15px;
  font-weight: 600;
  color: var(--brass-bright);
}
.footer__bottom {
  border-top: 1px solid var(--line-soft);
  padding: 24px 0;
}
.footer__bottom .container {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
  font-size: 13px;
  color: var(--text-faint);
}
.footer__motto {
  font-family: var(--font-serif);
  color: var(--copper);
  letter-spacing: .1em;
}

/* ============================================================
   Reveal 动画
   ============================================================ */
.reveal {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity .8s cubic-bezier(.2,.7,.2,1), transform .8s cubic-bezier(.2,.7,.2,1);
}
.reveal.is-visible {
  opacity: 1;
  transform: translateY(0);
}

/* ============================================================
   响应式
   ============================================================ */
@media (max-width: 900px) {
  .nav__links { display: none; }
  .nav__cta { display: none; }
  .nav__burger { display: flex; }

  .nav__links.open {
    display: flex;
    position: absolute;
    top: 100%; left: 0; right: 0;
    flex-direction: column;
    background: rgba(13,9,4,.97);
    backdrop-filter: blur(14px);
    padding: 20px 28px;
    gap: 8px;
    border-top: 1px solid var(--line-soft);
  }
  .nav__links.open a {
    padding: 14px 0;
    border-bottom: 1px solid var(--line-soft);
    font-size: 16px;
  }

  .about__grid { grid-template-columns: 1fr; gap: 48px; }
  .features__grid { grid-template-columns: repeat(2, 1fr); }
  .join__steps { grid-template-columns: 1fr; }
  .step:not(:last-child)::after { display: none; }
}

@media (max-width: 560px) {
  .section { padding: 80px 0; }
  .section__head { flex-wrap: wrap; margin-bottom: 40px; }
  .container, .nav__inner { padding: 0 20px; }

  .hero { padding: 100px 20px 80px; }
  .hero__actions { flex-direction: column; align-items: stretch; }
  .hero__actions .btn { justify-content: center; }
  .hero__domain-value { flex-direction: column; gap: 8px; padding: 16px 24px; }
  .hero__domain-copy { padding-left: 0; border-left: none; border-top: 1px solid var(--line); padding-top: 8px; }

  .features__grid { grid-template-columns: 1fr; }
  .about__stats { gap: 24px; }
  .join__ip { flex-direction: column; align-items: stretch; text-align: center; }
  .join__ip-value { justify-content: center; }

  .footer__inner { flex-direction: column; align-items: flex-start; }
  .footer__domain { text-align: left; }
  .footer__bottom .container { flex-direction: column; }
}

/* 减弱动画偏好 */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: .01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .01ms !important;
  }
  .reveal { opacity: 1; transform: none; }
}