/* ============================================================
   NORTHARC 北弧工作室 — Minimal Dark
   设计系统 + 全站样式（中/英共用）
   ============================================================ */

/* ---------- 字体（全部自托管） ---------- */
@font-face {
  font-family: "Archivo";
  src: url("../fonts/archivo-var.woff2") format("woff2");
  font-weight: 100 900;
  font-display: swap;
}
@font-face {
  font-family: "Noto Sans SC";
  src: url("../fonts/noto-sans-sc-subset.woff2") format("woff2");
  font-weight: 100 900;
  font-display: swap;
}
@font-face {
  font-family: "IBM Plex Mono";
  src: url("../fonts/plex-mono-latin-400.woff2") format("woff2");
  font-weight: 400;
  font-display: swap;
}
@font-face {
  font-family: "IBM Plex Mono";
  src: url("../fonts/plex-mono-latin-600.woff2") format("woff2");
  font-weight: 600;
  font-display: swap;
}

/* ---------- Design Tokens ---------- */
:root {
  /* 近纯黑 + 单一冷蓝强调色 */
  /* 极地冷灰：中性黑改为带冷调的石墨黑，文字、边框同调；强调色为「弧蓝」 */
  --c-bg: #0b0d12;
  --c-panel: #12151c;
  --c-panel-2: #191d26;
  --c-border: rgba(160, 180, 220, 0.12);
  --c-border-inner: rgba(160, 180, 220, 0.07);
  --c-border-strong: rgba(160, 180, 220, 0.22);
  --c-line: rgba(160, 180, 220, 0.06);
  --c-text: #eef1f7;
  --c-text-dim: #a4acbd;
  --c-text-faint: #7f8798;
  --c-accent: #5b8cff;
  --c-on-light: #0b0d12;

  --font-display: "Archivo", "Noto Sans SC", -apple-system, "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-body: "Archivo", "Noto Sans SC", -apple-system, BlinkMacSystemFont, "PingFang SC", "HarmonyOS Sans SC", "Microsoft YaHei", "Segoe UI", sans-serif;
  /* CJK 回退需在 generic monospace 之前，避免 mono 场景中文落到宋体 */
  --font-mono: "IBM Plex Mono", "SF Mono", ui-monospace, Menlo, Consolas, "Noto Sans SC", "PingFang SC", "Microsoft YaHei", monospace;

  --w-container: 70rem;
  --gutter: clamp(1.25rem, 4vw, 2.5rem);
  --radius: 1rem;
  --radius-sm: 0.5rem;

  --ease-out: cubic-bezier(0.22, 1, 0.36, 1);
  --dur: 0.22s;

  --z-nav: 100;
  --z-menu: 200;
  --z-banner: 300;
}

/* ---------- Reset ---------- */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}
html {
  color-scheme: dark;
  -webkit-text-size-adjust: 100%;
}
@media (prefers-reduced-motion: no-preference) {
  html {
    scroll-behavior: smooth;
  }
}
body {
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.75;
  color: var(--c-text);
  background-color: var(--c-bg);
  /* 极光氛围：顶部蓝、紫两团柔光 + 一抹青绿，形成「北」的极地意象 */
  background-image:
    radial-gradient(100rem 64rem at 20% -8rem, rgba(91, 140, 255, 0.16), transparent 72%),
    radial-gradient(80rem 52rem at 82% -6rem, rgba(151, 132, 255, 0.13), transparent 70%),
    radial-gradient(56rem 32rem at 50% 6rem, rgba(64, 200, 190, 0.07), transparent 60%);
  background-repeat: no-repeat;
  overflow-x: hidden;
}
/* 全站细颗粒：让暗色表面有材质而非平涂 */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: 1;
  pointer-events: none;
  opacity: 0.045;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='180' height='180'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.85' numOctaves='2' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='180' height='180' filter='url(%23n)' opacity='.7'/%3E%3C/svg%3E");
}
/* 区块色带与回光 */
.work {
  background: linear-gradient(180deg, transparent, rgba(160, 180, 220, 0.055) 12%, rgba(160, 180, 220, 0.055) 88%, transparent);
}
.pov {
  background: linear-gradient(180deg, transparent, rgba(160, 180, 220, 0.035) 20%, rgba(160, 180, 220, 0.035) 80%, transparent);
}
.contact {
  background: radial-gradient(56rem 18rem at 50% 70%, rgba(91, 140, 255, 0.13), transparent 62%);
}
img,
svg {
  max-width: 100%;
  display: block;
}
a {
  color: inherit;
  text-decoration: none;
}
ul,
ol {
  list-style: none;
}
button {
  font: inherit;
  color: inherit;
  background: none;
  border: 0;
  cursor: pointer;
}
em {
  font-style: normal;
}
::selection {
  background: rgba(91, 140, 255, 0.35);
  color: #fff;
}
:focus-visible {
  outline: 2px solid var(--c-accent);
  outline-offset: 3px;
  border-radius: 4px;
}

/* ---------- 工具类 ---------- */
.mono {
  font-family: var(--font-mono);
  letter-spacing: 0.08em;
}
.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
  border: 0;
}
.skip-link {
  position: fixed;
  top: -100%;
  left: 1rem;
  z-index: calc(var(--z-banner) + 1);
  padding: 0.6rem 1.1rem;
  background: var(--c-text);
  color: var(--c-on-light);
  border-radius: 999px;
  font-weight: 600;
  transition: top var(--dur) var(--ease-out);
}
.skip-link:focus-visible {
  top: 1rem;
}
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--c-text-faint);
}
.eyebrow__dot {
  width: 0.4rem;
  height: 0.4rem;
  border-radius: 50%;
  background: var(--c-accent);
}

/* 纵向参考线（Linear 式版式骨架，仅桌面） */
.page-lines {
  position: fixed;
  inset: 0;
  z-index: -1;
  max-width: var(--w-container);
  margin: 0 auto;
  pointer-events: none;
  display: none;
}
.page-lines span {
  position: absolute;
  top: 0;
  bottom: 0;
  width: 1px;
  background: var(--c-line);
}
.page-lines span:nth-child(1) { left: 0; }
.page-lines span:nth-child(2) { left: 50%; }
.page-lines span:nth-child(3) { right: 0; }
@media (min-width: 75em) {
  .page-lines {
    display: block;
  }
}

/* ---------- 导航 ---------- */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: var(--z-nav);
  transition: background-color var(--dur) ease, border-color var(--dur) ease;
  border-bottom: 1px solid transparent;
}
.site-header.is-scrolled {
  background: rgba(11, 13, 18, 0.82);
  -webkit-backdrop-filter: blur(12px) saturate(1.3);
  backdrop-filter: blur(12px) saturate(1.3);
  border-bottom-color: var(--c-border);
}
.nav {
  max-width: var(--w-container);
  margin: 0 auto;
  padding: 0 var(--gutter);
  height: 4rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}
.nav__logo {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  min-height: 44px;
  color: var(--c-text);
}
.nav__mark {
  width: 1.5rem;
  height: 1.5rem;
  flex: none;
}
.nav__wordmark {
  display: flex;
  align-items: baseline;
  gap: 0.55rem;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1rem;
  letter-spacing: 0.14em;
}
.nav__zh {
  font-size: 0.8rem;
  font-weight: 500;
  letter-spacing: 0.3em;
  color: var(--c-text-faint);
}
.nav__menu {
  display: flex;
  align-items: center;
  gap: 1.9rem;
}
.nav__links {
  display: flex;
  gap: 0.25rem;
}
.nav__links a {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  padding: 0 0.8rem;
  font-size: 0.92rem;
  color: var(--c-text-dim);
  border-radius: 999px;
  transition: color var(--dur) ease, background-color var(--dur) ease;
}
.nav__links a:hover,
.nav__links a:focus-visible {
  color: var(--c-text);
  background: rgba(255, 255, 255, 0.06);
}
.nav__actions {
  display: flex;
  align-items: center;
  gap: 0.9rem;
}
.nav__lang {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 44px;
  min-height: 44px;
  padding: 0 0.4rem;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  letter-spacing: 0.1em;
  color: var(--c-text-dim);
  border: 1px solid var(--c-border);
  border-radius: 999px;
  transition: color var(--dur) ease, border-color var(--dur) ease;
}
.nav__lang:hover,
.nav__lang:focus-visible {
  color: var(--c-text);
  border-color: var(--c-border-strong);
}
.nav__toggle {
  display: none;
  position: relative;
  z-index: calc(var(--z-menu) + 1);
  width: 44px;
  height: 44px;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 6px;
}
.nav__toggle-bar {
  width: 1.3rem;
  height: 1.5px;
  border-radius: 2px;
  background: var(--c-text);
  transition: transform var(--dur) var(--ease-out);
}
.nav__toggle[aria-expanded="true"] .nav__toggle-bar:first-child {
  transform: translateY(3.75px) rotate(45deg);
}
.nav__toggle[aria-expanded="true"] .nav__toggle-bar:last-child {
  transform: translateY(-3.75px) rotate(-45deg);
}

/* ---------- 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  min-height: 2.9rem;
  padding: 0.65rem 1.5rem;
  border-radius: 999px;
  font-family: var(--font-display);
  font-size: 0.95rem;
  font-weight: 600;
  letter-spacing: 0.01em;
  transition: transform var(--dur) var(--ease-out), background-color var(--dur) ease,
    border-color var(--dur) ease, color var(--dur) ease, box-shadow var(--dur) ease;
  touch-action: manipulation;
}
.btn--sm {
  min-height: 2.75rem;
  padding: 0.45rem 1.15rem;
  font-size: 0.88rem;
}
.btn--primary {
  background: var(--c-text);
  color: var(--c-on-light);
}
.btn--primary:hover,
.btn--primary:focus-visible {
  background: #ffffff;
  transform: translateY(-1px);
  box-shadow: 0 8px 30px -12px rgba(255, 255, 255, 0.35);
}
.btn--primary:active {
  transform: translateY(0) scale(0.98);
}
.btn--ghost {
  border: 1px solid var(--c-border-strong);
  color: var(--c-text);
}
.btn--ghost:hover,
.btn--ghost:focus-visible {
  border-color: rgba(255, 255, 255, 0.34);
  background: rgba(255, 255, 255, 0.04);
  transform: translateY(-1px);
}
.btn--ghost:active {
  transform: translateY(0) scale(0.98);
}
.btn__icon {
  width: 1.05rem;
  height: 1.05rem;
  transition: transform var(--dur) var(--ease-out);
}
.btn:hover .btn__icon {
  transform: translateX(3px);
}

/* ---------- Hero ---------- */
.hero {
  position: relative;
  min-height: 100vh; /* svh 回退 */
  min-height: 100svh;
  display: flex;
  align-items: center;
  overflow: hidden;
  padding: 7rem 0 9rem;
}
.hero__bg {
  position: absolute;
  inset: 0;
  z-index: -1;
}
.hero__arc {
  position: absolute;
  inset: auto 0 0 0;
  width: 100%;
  height: 48%;
}
.hero__inner {
  max-width: var(--w-container);
  margin: 0 auto;
  padding: 0 var(--gutter);
  width: 100%;
}
.hero__eyebrow {
  color: var(--c-text-dim);
  animation: rise 0.8s var(--ease-out) both;
}
.hero__title {
  margin: 1.5rem 0 1.6rem;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: clamp(2.5rem, 7.2vw, 4.9rem);
  line-height: 1.12;
  letter-spacing: -0.005em;
}
:lang(en) .hero__title {
  letter-spacing: -0.02em;
}
.hero__line {
  display: block;
  animation: rise 0.8s var(--ease-out) 0.1s both;
}
.hero__line + .hero__line {
  animation-delay: 0.22s;
}
.hl {
  background: linear-gradient(100deg, #a9c4ff 0%, var(--c-accent) 55%, #3f6fe0 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.hero__sub {
  max-width: 33em;
  font-size: clamp(1.05rem, 2.2vw, 1.125rem);
  text-wrap: pretty;
  color: var(--c-text-dim);
  animation: rise 0.8s var(--ease-out) 0.34s both;
}
:lang(en) .hero__sub {
  max-width: 40em;
}
.hero__sub strong {
  color: var(--c-text);
  font-weight: 600;
}
.hero__cta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.9rem;
  margin-top: 2.3rem;
  animation: rise 0.8s var(--ease-out) 0.46s both;
}
@keyframes rise {
  from {
    opacity: 0;
    transform: translateY(1.4rem);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* ---------- 区块通用 ---------- */
.section {
  padding: clamp(4.5rem, 9vw, 7rem) 0;
  scroll-margin-top: 4rem;
}
.section__inner {
  max-width: var(--w-container);
  margin: 0 auto;
  padding: 0 var(--gutter);
}
.section__head {
  max-width: 44em;
  margin-bottom: clamp(2.2rem, 5vw, 3.5rem);
}
.section__title {
  margin: 0.9rem 0 0.8rem;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: clamp(1.7rem, 4vw, 2.5rem);
  line-height: 1.2;
  letter-spacing: 0;
  text-wrap: balance;
}
.section__lead {
  color: var(--c-text-dim);
  font-size: clamp(1.02rem, 2vw, 1.125rem);
  text-wrap: pretty;
}

/* 滚动渐现（无 JS 时不隐藏内容） */
html.js .reveal {
  opacity: 0;
  transform: translateY(1.2rem);
}
html.js .reveal.is-in {
  opacity: 1;
  transform: none;
  transition: opacity 0.6s var(--ease-out) var(--d, 0s), transform 0.6s var(--ease-out) var(--d, 0s);
}

/* ---------- 卡片 ---------- */
.card {
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.035) 0%, rgba(255, 255, 255, 0) 40%), var(--c-panel);
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.05);
  transition: transform var(--dur) var(--ease-out), border-color var(--dur) ease,
    background-color var(--dur) ease, box-shadow var(--dur) ease;
}
.card:hover {
  background-color: var(--c-panel-2);
  border-color: var(--c-border-strong);
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.09);
  transform: translateY(-2px);
}
/* 案例区有色带垫底，卡片需再抬一阶才能「浮」在色带上 */
.work .card {
  background-color: #1c2029;
}
.work .card:hover {
  background-color: #222734;
}
.work .work-card__cover {
  background: #1f2430;
}

/* ---------- 服务 ---------- */
.services__grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1.25rem;
}
.service-card {
  display: flex;
  flex-direction: column;
  padding: 1.7rem 1.5rem;
}
.service-card__icon {
  width: 2.75rem;
  height: 2.75rem;
  display: grid;
  place-items: center;
  border-radius: 0.7rem;
  color: var(--c-text);
  background: var(--c-panel-2);
  border: 1px solid var(--c-border-inner);
  transition: color var(--dur) ease, border-color var(--dur) ease;
}
.service-card__icon svg {
  width: 1.6rem;
  height: 1.6rem;
}
.service-card:hover .service-card__icon {
  color: var(--c-accent);
  border-color: var(--c-border-strong);
}
.service-card__title {
  margin-top: 1.2rem;
  font-family: var(--font-display);
  font-weight: 640;
  font-size: 1.16rem;
  letter-spacing: -0.01em;
}
.service-card__en {
  margin-top: 0.2rem;
  font-size: 0.68rem;
  letter-spacing: 0.14em;
  white-space: nowrap;
  text-transform: uppercase;
  color: var(--c-text-faint);
}
.service-card__desc {
  margin-top: 0.8rem;
  font-size: 0.9375rem;
  line-height: 1.7;
  color: var(--c-text-dim);
  text-wrap: pretty;
}
.tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  margin-top: auto;
  padding-top: 1.05rem;
}
.tags li {
  font-family: var(--font-body);
  font-size: 0.76rem;
  font-weight: 500;
  letter-spacing: 0.01em;
  color: var(--c-text-dim);
  padding: 0.22rem 0.62rem;
  border: 1px solid var(--c-border-inner);
  border-radius: 999px;
  background: var(--c-panel-2);
  white-space: nowrap;
}

/* ---------- 服务承诺 ---------- */
.promise {
  padding-block: 0;
}
.promise__eyebrow {
  display: flex;
  justify-content: center;
  margin-bottom: 2rem;
}
.promise__grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  border-block: 1px solid var(--c-border);
}
.promise__item {
  padding: 2.2rem 1rem;
  text-align: center;
}
.promise__item + .promise__item {
  border-left: 1px solid var(--c-border);
}
.promise__num {
  display: block;
  font-family: var(--font-display);
  font-size: clamp(2.2rem, 5vw, 3.2rem);
  font-weight: 650;
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--c-text);
  font-variant-numeric: tabular-nums;
}
.promise__unit {
  font-size: 0.42em;
  font-weight: 600;
  color: var(--c-accent);
  margin-left: 0.12em;
}
.promise__label {
  display: block;
  margin-top: 0.65rem;
  font-size: 0.9rem;
  color: var(--c-text-dim);
}

/* ---------- 典型方案 ---------- */
.work__grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.25rem;
}
.work-card {
  overflow: hidden;
  display: flex;
  flex-direction: column;
}
.work-card__cover {
  position: relative;
  aspect-ratio: 7 / 5;
  overflow: hidden;
  background: var(--c-panel-2);
  border-bottom: 1px solid var(--c-border);
}
/* 每个方案一个柔和的顶部光晕 */
.work-card__cover::before {
  content: "";
  position: absolute;
  inset: 0;
  background:
    linear-gradient(180deg, rgba(255, 255, 255, 0.03), transparent 40%),
    radial-gradient(90% 70% at 50% -15%, var(--glow), transparent 68%);
  opacity: 0.75;
  transition: opacity 0.5s ease;
}
.work-card:hover .work-card__cover::before {
  opacity: 1;
}
.work-card__cover--a { --glow: rgba(88, 196, 255, 0.18); }
.work-card__cover--b { --glow: rgba(91, 140, 255, 0.22); }
.work-card__cover--c { --glow: rgba(151, 132, 255, 0.2); }
.work-card__cover--d { --glow: rgba(64, 200, 190, 0.18); }
.work-card__cover--e { --glow: rgba(120, 130, 255, 0.18); }
.work-card__cover--f { --glow: rgba(96, 170, 255, 0.16); }
.work-card__art {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  transition: transform 0.6s var(--ease-out);
}
.work-card:hover .work-card__art {
  transform: translateY(-6px);
}
.work-card__art .frag {
  transition: transform 0.6s var(--ease-out);
}
.work-card:hover .frag {
  transform: translateY(-6px);
}
.work-card__body {
  padding: 1.5rem 1.6rem 1.7rem;
  display: flex;
  flex-direction: column;
  flex: 1;
}
.work-card__cat {
  font-family: var(--font-body);
  font-size: 0.74rem;
  font-weight: 500;
  letter-spacing: 0.1em;
  color: var(--c-accent);
}
.work-card__title {
  margin-top: 0.6rem;
  font-family: var(--font-display);
  font-weight: 640;
  font-size: 1.3rem;
  letter-spacing: -0.012em;
}
.work-card__desc {
  margin-top: 0.65rem;
  font-size: 1rem;
  color: var(--c-text-dim);
  text-wrap: pretty;
  flex: 1;
}

/* ---------- 领域（3 列） ---------- */
.services__grid--domains {
  grid-template-columns: repeat(3, 1fr);
}

/* ---------- 工程标准带 ---------- */
.standards {
  padding-block: 0;
}
.standards__eyebrow {
  display: flex;
  justify-content: center;
  margin-bottom: 2rem;
}
.standards__grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  border-block: 1px solid var(--c-border);
}
.standards__item {
  padding: 2rem 1.6rem 2.2rem;
}
.standards__item + .standards__item {
  border-left: 1px solid var(--c-border);
}
.standards__title {
  font-family: var(--font-display);
  font-weight: 640;
  font-size: 1.08rem;
  letter-spacing: -0.01em;
  text-wrap: balance;
}
.standards__desc {
  margin-top: 0.55rem;
  font-size: 0.9375rem;
  line-height: 1.7;
  color: var(--c-text-dim);
  text-wrap: pretty;
}

/* ---------- 合作模式 ---------- */
.engage__grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.25rem;
}
.engage-card {
  padding: 1.9rem 1.7rem 2rem;
  display: flex;
  flex-direction: column;
}
.engage-card__num {
  font-family: var(--font-display);
  font-size: 2rem;
  font-weight: 650;
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--c-text-faint);
}
.engage-card__title {
  margin-top: 1.4rem;
  font-family: var(--font-display);
  font-weight: 640;
  font-size: 1.3rem;
  letter-spacing: -0.012em;
}
.engage-card__desc {
  margin-top: 0.7rem;
  font-size: 1rem;
  color: var(--c-text-dim);
  text-wrap: pretty;
}
.engage-card__fit {
  margin-top: auto;
  padding-top: 1.4rem;
  font-size: 0.9375rem;
  line-height: 1.7;
  color: var(--c-text-dim);
  border-top: 1px solid var(--c-border-inner);
  text-wrap: pretty;
}
.engage-card__fit span {
  display: inline-block;
  margin-right: 0.5rem;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--c-accent);
}

/* ---------- 主张 ---------- */
@media (min-width: 62em) {
  :lang(zh) .pov__text {
    word-break: keep-all;
  }
}
.pov .section__head {
  margin-bottom: clamp(1.5rem, 3vw, 2.2rem);
}
.pov__list {
  border-top: 1px solid var(--c-border);
}
.pov__item {
  display: grid;
  grid-template-columns: 4.5rem 1fr;
  gap: 1rem;
  align-items: baseline;
  padding: 1.8rem 0;
  border-bottom: 1px solid var(--c-border);
}
.pov__num {
  font-size: 0.8rem;
  letter-spacing: 0.2em;
  color: var(--c-text-faint);
}
.pov__text {
  font-family: var(--font-display);
  font-weight: 560;
  font-size: clamp(1.25rem, 2.6vw, 1.85rem);
  line-height: 1.35;
  letter-spacing: -0.012em;
  max-width: 26em;
  text-wrap: balance;
}

/* ---------- 流程 ---------- */
.process__list {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0;
  border-block: 1px solid var(--c-border);
}
.process__step {
  position: relative;
  padding: 1.75rem 1.75rem 2rem;
  border-left: 1px solid var(--c-border);
}
.process__step:nth-child(3n + 1) {
  border-left: 0;
  padding-left: 0;
}
.process__step:nth-child(n + 4) {
  border-top: 1px solid var(--c-border);
}
.process__step::before {
  content: "";
  position: absolute;
  top: -1px;
  left: 0;
  width: 2.4rem;
  height: 1.5px;
  background: var(--c-accent);
}
.process__step:nth-child(3n + 1)::before {
  left: 0;
}
.process__step:not(:nth-child(3n + 1))::before {
  left: 1.75rem;
}
.process__num {
  font-family: var(--font-display);
  font-size: 2rem;
  font-weight: 650;
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--c-text-faint);
  font-variant-numeric: tabular-nums;
}
.process__name {
  margin-top: 1.25rem;
  font-family: var(--font-display);
  font-weight: 640;
  font-size: 1.2rem;
  letter-spacing: -0.01em;
}
.process__desc {
  margin-top: 0.5rem;
  font-size: 0.9375rem;
  line-height: 1.7;
  color: var(--c-text-dim);
  max-width: 22em;
  text-wrap: pretty;
}

/* ---------- 技术栈跑马灯 ---------- */
.stack {
  position: relative;
  padding: 3rem 0;
  border-block: 1px solid var(--c-border);
  overflow: hidden;
}
.stack__head {
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 1.4rem;
}
.stack__pause {
  position: absolute;
  top: calc(3rem + 0.6rem); /* 对齐眉题行中线，避免压到跑马灯 */
  right: max(var(--gutter), calc(50% - var(--w-container) / 2 + var(--gutter)));
  transform: translateY(-50%);
  display: grid;
  place-items: center;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  border: 1px solid var(--c-border);
  color: var(--c-text-faint);
  transition: color var(--dur) ease, border-color var(--dur) ease;
}
.stack__pause:hover,
.stack__pause:focus-visible {
  color: var(--c-text);
  border-color: var(--c-border-strong);
}
.stack__pause-icon {
  width: 0.85rem;
  height: 0.85rem;
}
.stack__pause .stack__pause-icon--play {
  display: none;
}
.stack__pause[aria-pressed="true"] .stack__pause-icon--pause {
  display: none;
}
.stack__pause[aria-pressed="true"] .stack__pause-icon--play {
  display: block;
}
.marquee {
  --gap: 3.25rem;
  display: flex;
  overflow: hidden;
  -webkit-mask-image: linear-gradient(90deg, transparent, #000 12%, #000 88%, transparent);
  mask-image: linear-gradient(90deg, transparent, #000 12%, #000 88%, transparent);
}
.marquee__track {
  display: flex;
  align-items: center;
  gap: var(--gap);
  padding-right: var(--gap);
  flex: none;
  animation: marquee 40s linear infinite;
}
/* 悬停 / 键盘聚焦到暂停按钮 / 按钮暂停（WCAG 2.2.2）——按钮在 .stack__head 内，故用 .stack 作焦点祖先 */
.marquee:hover .marquee__track,
.stack:focus-within .marquee__track,
.marquee.is-paused .marquee__track {
  animation-play-state: paused;
}
.marquee__track li {
  font-family: var(--font-mono);
  font-size: clamp(0.92rem, 2vw, 1.15rem);
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--c-text-faint);
  white-space: nowrap;
  display: flex;
  align-items: center;
  gap: var(--gap);
}
.marquee__track li::after {
  content: "";
  width: 0.3rem;
  height: 0.3rem;
  border-radius: 50%;
  background: rgba(91, 140, 255, 0.45);
  flex: none;
}
@keyframes marquee {
  to {
    transform: translateX(-100%);
  }
}

/* ---------- 关于 ---------- */
.about__inner {
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  gap: clamp(2.5rem, 6vw, 5rem);
  align-items: center;
}
.about__p {
  margin-top: 1.1rem;
  color: var(--c-text-dim);
  font-size: 1rem;
  text-wrap: pretty;
}
.about__points {
  margin-top: 2rem;
  display: grid;
  gap: 1.4rem;
}
.about__points li {
  display: flex;
  gap: 1rem;
  align-items: flex-start;
}
.about__point-icon {
  width: 1.45rem;
  height: 1.45rem;
  flex: none;
  margin-top: 0.2rem;
  color: var(--c-accent);
  background: var(--c-panel-2);
  border: 1px solid var(--c-border-inner);
  border-radius: 50%;
  padding: 0.28rem;
}
.about__point-title {
  font-family: var(--font-display);
  font-size: 1.02rem;
  font-weight: 640;
}
.about__points p {
  margin-top: 0.2rem;
  font-size: 0.9375rem;
  line-height: 1.7;
  color: var(--c-text-dim);
  text-wrap: pretty;
}
.about__figure {
  color: var(--c-text-dim);
}

/* ---------- 联系 ---------- */
.contact__grid {
  display: grid;
  grid-template-columns: 1fr;
}
.contact__list {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(17rem, 1fr));
  gap: 1.25rem;
  align-items: stretch;
}
.contact__row {
  display: flex;
  gap: 1.05rem;
  align-items: center;
  padding: 1.35rem 1.5rem;
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.035) 0%, rgba(255, 255, 255, 0) 40%), var(--c-panel);
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.05);
  transition: border-color var(--dur) ease, background-color var(--dur) ease, box-shadow var(--dur) ease;
}
.contact__row:hover {
  background-color: var(--c-panel-2);
  border-color: var(--c-border-strong);
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.09);
}
.contact__row > div {
  display: flex;
  flex-direction: column;
  gap: 0.15rem;
}
.contact__icon {
  width: 1.4rem;
  height: 1.4rem;
  flex: none;
  color: var(--c-accent);
}
.contact__label {
  display: block;
  margin-bottom: 0.1rem;
  font-size: 0.78rem;
  letter-spacing: 0.06em;
  color: var(--c-text-faint);
}
.contact__value {
  display: inline-flex;
  align-items: center;
  min-height: 2.25rem;
  padding: 0.2rem 0;
  line-height: 1.35;
  font-size: 1.04rem;
  font-weight: 600;
  color: var(--c-text);
  transition: color var(--dur) ease;
}
@media (pointer: coarse) {
  a.contact__value {
    min-height: 44px;
  }
}
a.contact__value:hover,
a.contact__value:focus-visible {
  color: var(--c-accent);
}

/* ---------- 页脚 ---------- */
.footer {
  border-top: 1px solid var(--c-border);
  padding: 3.25rem 0 3rem;
}
.footer__inner {
  max-width: var(--w-container);
  margin: 0 auto;
  padding: 0 var(--gutter);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 1.2rem;
}
.footer__brand {
  font-family: var(--font-display);
  font-weight: 700;
  letter-spacing: 0.12em;
}
.footer__zh {
  font-size: 0.8rem;
  font-weight: 500;
  letter-spacing: 0.24em;
  color: var(--c-text-faint);
  margin-left: 0.6rem;
}
.footer__nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.2rem;
}
.footer__nav a {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  padding: 0 0.7rem;
  font-size: 0.86rem;
  color: var(--c-text-dim);
  border-radius: 999px;
  transition: color var(--dur) ease, background-color var(--dur) ease;
}
.footer__nav a:hover,
.footer__nav a:focus-visible {
  color: var(--c-text);
  background: rgba(255, 255, 255, 0.06);
}
.footer__legal {
  width: 100%;
  font-size: 0.78rem;
  color: var(--c-text-faint);
}
.footer__legal a {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  text-decoration: underline;
  text-underline-offset: 3px;
  transition: color var(--dur) ease;
}
.footer__legal a:hover {
  color: var(--c-text-dim);
}

/* ---------- 语言建议横幅（JS 注入） ---------- */
.lang-banner {
  position: fixed;
  left: 50%;
  bottom: 1.2rem;
  transform: translateX(-50%);
  z-index: var(--z-banner);
  display: flex;
  align-items: center;
  gap: 0.7rem;
  max-width: min(92vw, 30rem);
  padding: 0.55rem 0.55rem 0.55rem 1.2rem;
  background: rgba(18, 21, 28, 0.94);
  -webkit-backdrop-filter: blur(12px);
  backdrop-filter: blur(12px);
  border: 1px solid var(--c-border-strong);
  border-radius: 999px;
  box-shadow: 0 18px 48px -18px rgba(0, 0, 0, 0.9);
  animation: rise-centered 0.5s var(--ease-out) both;
}
@keyframes rise-centered {
  from {
    opacity: 0;
    transform: translate(-50%, 1.4rem);
  }
  to {
    opacity: 1;
    transform: translate(-50%, 0);
  }
}
.lang-banner__text {
  font-size: 0.88rem;
  color: var(--c-text-dim);
}
.lang-banner__link {
  font-weight: 600;
  color: var(--c-accent);
  white-space: nowrap;
  min-height: 44px;
  display: inline-flex;
  align-items: center;
}
.lang-banner__close {
  width: 44px;
  height: 44px;
  flex: none;
  display: grid;
  place-items: center;
  border-radius: 50%;
  color: var(--c-text-faint);
  transition: color var(--dur) ease, background-color var(--dur) ease;
}
.lang-banner__close:hover {
  color: var(--c-text);
  background: rgba(255, 255, 255, 0.06);
}
/* 全屏菜单打开时隐藏横幅：其 z-index(300) 高于被困在 header 层叠上下文里的菜单遮罩 */
body.menu-open .lang-banner {
  display: none;
}

/* ============================================================
   响应式
   ============================================================ */
@media (max-width: 74.99em) {
  .services__grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .services__grid--domains {
    grid-template-columns: repeat(3, 1fr);
  }
}
@media (max-width: 61.99em) {
  .services__grid--domains,
  .engage__grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .standards__grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .standards__item:nth-child(3) {
    border-left: 0;
  }
  .standards__item:nth-child(n + 3) {
    border-top: 1px solid var(--c-border);
  }
  .process__list {
    grid-template-columns: repeat(2, 1fr);
  }
  .process__step:nth-child(3n + 1) {
    border-left: 1px solid var(--c-border);
    padding-left: 1.75rem;
  }
  .process__step:nth-child(odd) {
    border-left: 0;
    padding-left: 0;
  }
  .process__step:nth-child(n + 4) {
    border-top: 0;
  }
  .process__step:nth-child(n + 3) {
    border-top: 1px solid var(--c-border);
  }
  .process__step::before,
  .process__step:not(:nth-child(3n + 1))::before {
    left: 1.75rem;
  }
  .process__step:nth-child(odd)::before {
    left: 0;
  }
  .about__inner {
    grid-template-columns: 1fr;
  }
  .about__figure {
    width: min(100%, 14rem);
    justify-self: center;
    margin: 0;
  }
  .about__arcfig {
    width: 100%;
    height: auto;
  }
  .contact__grid {
    grid-template-columns: 1fr;
  }
}
@media (max-width: 47.99em) {
  .nav__toggle {
    display: flex;
  }
  .nav__menu {
    position: fixed;
    inset: 0;
    z-index: var(--z-menu);
    flex-direction: column;
    justify-content: center;
    gap: 2.75rem;
    background: rgba(11, 13, 18, 0.97);
    -webkit-backdrop-filter: blur(16px);
    backdrop-filter: blur(16px);
    opacity: 0;
    visibility: hidden;
    transition: opacity var(--dur) ease, visibility 0s linear var(--dur);
  }
  .nav__menu.is-open {
    opacity: 1;
    visibility: visible;
    transition-delay: 0s;
  }
  .nav__links {
    flex-direction: column;
    align-items: center;
    gap: 0.4rem;
  }
  .nav__links a {
    font-family: var(--font-display);
    font-size: 1.55rem;
    font-weight: 640;
    letter-spacing: -0.01em;
    color: var(--c-text);
    padding: 0.35rem 1.2rem;
    opacity: 0;
    transform: translateY(0.9rem);
    transition: opacity 0.4s var(--ease-out), transform 0.4s var(--ease-out);
  }
  .nav__menu.is-open .nav__links a {
    opacity: 1;
    transform: none;
    transition-delay: calc(0.05s * var(--i, 0) + 0.08s);
  }
  .nav__actions {
    flex-direction: column;
    gap: 1.3rem;
    opacity: 0;
    transition: opacity 0.4s var(--ease-out) 0.36s;
  }
  .nav__menu.is-open .nav__actions {
    opacity: 1;
  }

  .nav__toggle {
    margin-right: -0.725rem;
  }
  body {
    background-image:
      radial-gradient(60rem 70rem at 20% -14rem, rgba(91, 140, 255, 0.2), transparent 62%),
      radial-gradient(48rem 56rem at 85% -10rem, rgba(151, 132, 255, 0.15), transparent 62%),
      radial-gradient(40rem 30rem at 50% 8rem, rgba(64, 200, 190, 0.07), transparent 60%);
  }
  .standards__eyebrow {
    justify-content: flex-start;
  }
  .hero {
    align-items: flex-start;
    padding: 7.5rem 0 5rem;
  }
  .hero__arc {
    height: 34%;
  }
  .hero__sub {
    text-wrap: balance;
  }
  .hero__cta .btn {
    flex: 1 1 calc(50% - 0.45rem);
    min-width: max-content;
    justify-content: center;
  }
  .services__grid,
  .services__grid--domains,
  .engage__grid,
  .process__list {
    grid-template-columns: 1fr;
  }
  .standards__grid {
    grid-template-columns: 1fr;
  }
  .standards__item + .standards__item {
    border-left: 0;
    border-top: 1px solid var(--c-border);
  }
  .standards__item {
    padding: 1.4rem 0 1.5rem;
  }
  .pov__item {
    grid-template-columns: 3rem 1fr;
    padding: 1.4rem 0;
  }
  /* 案例：横向 scroll-snap 卡片流，避免六张大卡纵向堆满四屏 */
  .work__grid {
    display: flex;
    gap: 0.9rem;
    overflow-x: auto;
    scroll-snap-type: x mandatory;
    scroll-padding-inline: var(--gutter);
    margin-inline: calc(-1 * var(--gutter));
    padding-inline: var(--gutter);
    padding-bottom: 0.5rem;
    scrollbar-width: none;
    overscroll-behavior-x: contain;
  }
  .work__grid::-webkit-scrollbar {
    display: none;
  }
  .work-card {
    flex: 0 0 min(84vw, 20rem);
    scroll-snap-align: start;
  }
  html.js .work-card.reveal {
    transform: none;
  }
  .work-card__body {
    padding: 1.25rem 1.25rem 1.4rem;
  }
  /* 流程：序号并入左侧导轨 */
  .process__step,
  .process__step:nth-child(odd),
  .process__step:nth-child(3n + 1) {
    display: grid;
    grid-template-columns: 2.4rem 1fr;
    column-gap: 0.6rem;
    align-items: baseline;
    padding: 1.1rem 0 1.25rem;
    border-left: 0;
    border-top: 0;
  }
  .process__step + .process__step {
    border-top: 1px solid var(--c-border);
  }
  .process__step::before,
  .process__step:nth-child(odd)::before,
  .process__step:not(:nth-child(3n + 1))::before {
    left: 0;
  }
  .process__num {
    grid-row: 1;
    font-size: 1.4rem;
  }
  .process__name {
    grid-column: 2;
    margin-top: 0;
  }
  .process__desc {
    grid-column: 2;
    margin-top: 0.3rem;
  }
  .promise__grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .promise__num {
    font-size: 2.75rem;
  }
  .promise__item {
    padding: 1.5rem 0.5rem;
  }
  .about__figure {
    display: none;
  }
  .about__inner {
    gap: 0;
  }
  .footer__nav {
    margin-left: -0.7rem;
  }
  .promise__item:nth-child(3) {
    border-left: 0;
  }
  .promise__item:nth-child(n + 3) {
    border-top: 1px solid var(--c-border);
  }
  .footer__inner {
    flex-direction: column;
    align-items: flex-start;
    gap: 1.4rem;
  }
}

/* ============================================================
   动效降级 / 强制配色 / 打印
   ============================================================ */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-delay: 0s !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    transition-delay: 0s !important;
  }
  html {
    scroll-behavior: auto;
  }
  html.js .reveal {
    opacity: 1;
    transform: none;
  }
  .marquee {
    -webkit-mask-image: none;
    mask-image: none;
  }
  .marquee__track {
    animation: none;
    width: 100%;
    flex: 1 1 auto;
    min-width: 0;
    flex-wrap: wrap;
    justify-content: center;
    padding: 0 var(--gutter);
  }
  .marquee__track--clone {
    display: none;
  }
  .stack__pause {
    display: none;
  }
}

@media (forced-colors: active) {
  .nav__toggle-bar {
    background: CanvasText;
  }
  .eyebrow__dot {
    background: CanvasText;
  }
  .marquee__track li::after {
    background: CanvasText;
  }
}

@media print {
  :root {
    --c-text: #000;
    --c-text-dim: #333;
    --c-text-faint: #555;
    --c-border: #ccc;
    --c-border-strong: #999;
    --c-panel: #fff;
    --c-panel-2: #fff;
  }
  html {
    color-scheme: light;
    background: #fff;
  }
  body {
    background: #fff;
    color: #000;
  }
  /* 未滚入视口的渐现元素在纸上必须可见 */
  html.js .reveal {
    opacity: 1 !important;
    transform: none !important;
  }
  .site-header,
  .skip-link,
  .page-lines,
  .hero__bg,
  .lang-banner,
  .stack__pause,
  .nav__toggle {
    display: none !important;
  }
  body::before {
    display: none;
  }
  .work,
  .pov,
  .contact {
    background: none;
  }
  .hero {
    min-height: auto;
    padding: 2rem 0;
  }
  .card,
  .work .card,
  .contact__row {
    background: #fff;
    border-color: #ccc;
  }
  .work-card__cover {
    background: #fff;
  }
  .work-card__cover::before {
    display: none;
  }
  .hl {
    -webkit-background-clip: initial;
    background-clip: initial;
    background: none;
    color: #000;
  }
  .marquee {
    -webkit-mask-image: none;
    mask-image: none;
  }
  .marquee__track {
    animation: none;
    width: 100%;
    flex: 1 1 auto;
    min-width: 0;
    flex-wrap: wrap;
    justify-content: center;
    padding: 0 var(--gutter);
  }
  .marquee__track--clone {
    display: none;
  }
  a.contact__value::after {
    content: " (" attr(href) ")";
    font-size: 0.8em;
    color: #555;
  }
}