/* ==========================================================================
   搭台智能 DATAI · 官网样式
   设计方向：工程蓝图 —— 技术网格、发丝线、编号章节、等宽标注
   ========================================================================== */

/* ---------- 1. 设计令牌 ---------- */
:root {
  /* 深色（Hero / Footer / 深色区块） */
  --ink-900: #0A0F16;
  --ink-800: #101B2A;
  --ink-700: #17263C;
  --ink-600: #22344F;

  /* 品牌色 —— 用于深色底 */
  --blue: #96DEFF;
  --orange: #FF914D;

  /* 品牌色 —— 用于浅色底（加深以保证对比度达 WCAG AA） */
  --blue-deep: #0B6EA8;
  --orange-deep: #B8501A;

  /* 浅色正文 */
  --paper: #FFFFFF;
  --paper-alt: #F4F8FC;
  --paper-warm: #FFF9F4;
  --line: #E1E9F3;
  --line-strong: #C8D6E6;

  /* 文字 */
  --text: #16202E;
  --text-muted: #566476;
  --text-soft: #8794A6;

  /* 深色底上的文字 */
  --on-ink: #EAF2FA;
  --on-ink-muted: #93A6BC;

  /* 尺度 */
  --wrap: 1140px;
  --wrap-narrow: 780px;
  --gap: clamp(1.25rem, 3vw, 2rem);
  --section-y: clamp(4rem, 9vw, 7.5rem);

  /* 字体 */
  --font: "PingFang SC", "HarmonyOS Sans SC", "Microsoft YaHei",
          "Source Han Sans SC", "Noto Sans SC", -apple-system,
          BlinkMacSystemFont, "Segoe UI", sans-serif;
  --mono: ui-monospace, "SF Mono", "Cascadia Code", "JetBrains Mono",
          Consolas, "Liberation Mono", monospace;

  --radius: 3px;
  --radius-lg: 6px;
}

/* ---------- 2. 基础 ---------- */
*, *::before, *::after { box-sizing: border-box; }

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.8;              /* 中文需要更宽松的行高 */
  color: var(--text);
  background: var(--paper);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
}

img, svg { max-width: 100%; height: auto; display: block; }

a { color: var(--blue-deep); text-decoration: none; }
a:hover { text-decoration: underline; text-underline-offset: 3px; }

h1, h2, h3, h4 {
  margin: 0;
  line-height: 1.35;
  font-weight: 600;
  letter-spacing: -0.01em;
}

p { margin: 0; }

::selection { background: var(--blue); color: var(--ink-900); }

:focus-visible {
  outline: 2px solid var(--orange);
  outline-offset: 3px;
  border-radius: 2px;
}

/* ---------- 3. 布局 ---------- */
.wrap {
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding-inline: clamp(1.25rem, 4vw, 2.5rem);
}
.wrap--narrow { max-width: var(--wrap-narrow); }

.section { padding-block: var(--section-y); position: relative; }
.section--alt { background: var(--paper-alt); }
.section--ink {
  background: linear-gradient(160deg, var(--ink-900) 0%, var(--ink-800) 60%, var(--ink-700) 100%);
  color: var(--on-ink);
}

/* 章节头 —— 编号 + 标题 + 引语 */
.sec-head { margin-bottom: clamp(2rem, 4vw, 3.25rem); max-width: 46rem; }
.sec-head--center { margin-inline: auto; text-align: center; }

.eyebrow {
  font-family: var(--mono);
  font-size: 0.75rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--blue-deep);
  display: flex;
  align-items: center;
  gap: 0.7rem;
  margin-bottom: 1rem;
}
.eyebrow::before {
  content: "";
  width: 26px;
  height: 1px;
  background: currentColor;
  flex: none;
  opacity: 0.55;
}
.sec-head--center .eyebrow { justify-content: center; }
.section--ink .eyebrow { color: var(--blue); }

.sec-title {
  font-size: clamp(1.5rem, 3.6vw, 2.35rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 0.9rem;
  text-wrap: balance;
}
.sec-lead {
  font-size: clamp(1rem, 1.6vw, 1.125rem);
  color: var(--text-muted);
  line-height: 1.85;
}
.section--ink .sec-lead { color: var(--on-ink-muted); }

/* ---------- 4. 装饰母题：工程网格 + 圆环 ---------- */
.bg-grid {
  position: absolute;
  inset: 0;
  pointer-events: none;
  background-image:
    linear-gradient(to right, rgba(150, 222, 255, 0.055) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(150, 222, 255, 0.055) 1px, transparent 1px);
  background-size: 56px 56px;
  mask-image: radial-gradient(ellipse 90% 70% at 50% 40%, #000 20%, transparent 78%);
  -webkit-mask-image: radial-gradient(ellipse 90% 70% at 50% 40%, #000 20%, transparent 78%);
}
.bg-grid--light {
  background-image:
    linear-gradient(to right, rgba(11, 110, 168, 0.05) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(11, 110, 168, 0.05) 1px, transparent 1px);
  mask-image: radial-gradient(ellipse 80% 60% at 50% 0%, #000 10%, transparent 75%);
  -webkit-mask-image: radial-gradient(ellipse 80% 60% at 50% 0%, #000 10%, transparent 75%);
}

/* 圆环 —— 呼应 logo 的台面 / 镜片聚焦 */
.ring {
  position: absolute;
  border-radius: 50%;
  pointer-events: none;
  border: 1px solid rgba(150, 222, 255, 0.16);
}
.ring--glow {
  box-shadow:
    0 0 90px 12px rgba(150, 222, 255, 0.10),
    inset 0 0 70px rgba(150, 222, 255, 0.05);
}

/* ---------- 5. 页眉 ---------- */
.hdr {
  position: sticky;
  top: 0;
  z-index: 80;
  background: rgba(10, 15, 22, 0.82);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid rgba(150, 222, 255, 0.12);
}
.hdr__in {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  min-height: 68px;
}
.hdr__logo { display: block; flex: none; }
.hdr__logo svg, .hdr__logo img { height: 34px; width: auto; }

.nav { display: flex; align-items: center; gap: clamp(0.5rem, 2vw, 1.75rem); }
.nav a {
  color: var(--on-ink-muted);
  font-size: 0.9375rem;
  padding: 0.4rem 0;
  position: relative;
  transition: color 0.2s;
  white-space: nowrap;
}
.nav a:hover, .nav a[aria-current="page"] { color: var(--on-ink); text-decoration: none; }
.nav a[aria-current="page"]::after {
  content: "";
  position: absolute;
  left: 0; right: 0; bottom: -2px;
  height: 2px;
  background: var(--orange);
}

.nav__cta {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  border: 1px solid rgba(150, 222, 255, 0.4);
  color: var(--blue) !important;
  padding: 0.5rem 1.05rem !important;
  border-radius: var(--radius);
  font-size: 0.875rem !important;
  transition: background 0.2s, border-color 0.2s, color 0.2s;
}
.nav__cta:hover {
  background: var(--blue);
  color: var(--ink-900) !important;
  border-color: var(--blue);
  text-decoration: none;
}

/* 移动端菜单 */
.nav-toggle {
  display: none;
  background: none;
  border: 1px solid rgba(150, 222, 255, 0.3);
  border-radius: var(--radius);
  padding: 0.5rem 0.6rem;
  cursor: pointer;
  color: var(--blue);
}
.nav-toggle span {
  display: block;
  width: 18px; height: 1.5px;
  background: currentColor;
  margin: 3.5px 0;
  transition: transform 0.25s, opacity 0.25s;
}
.nav-toggle[aria-expanded="true"] span:nth-child(1) { transform: translateY(5px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] span:nth-child(3) { transform: translateY(-5px) rotate(-45deg); }

@media (max-width: 900px) {
  .nav-toggle { display: block; }
  .nav {
    position: fixed;
    inset: 68px 0 auto 0;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    background: var(--ink-900);
    border-bottom: 1px solid rgba(150, 222, 255, 0.16);
    padding: 0.5rem 0 1.25rem;
    transform: translateY(-120%);
    transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    max-height: calc(100vh - 68px);
    overflow-y: auto;
  }
  .nav.is-open { transform: translateY(0); }
  .nav a {
    padding: 0.9rem clamp(1.25rem, 4vw, 2.5rem);
    border-bottom: 1px solid rgba(150, 222, 255, 0.08);
    font-size: 1rem;
  }
  .nav a[aria-current="page"]::after { display: none; }
  .nav a[aria-current="page"] { color: var(--blue); }
  .nav__cta {
    margin: 1rem clamp(1.25rem, 4vw, 2.5rem) 0;
    justify-content: center;
    border-bottom: none !important;
  }
}

/* ---------- 6. Hero ---------- */
.hero {
  position: relative;
  background: linear-gradient(160deg, var(--ink-900) 0%, var(--ink-800) 58%, var(--ink-700) 100%);
  color: var(--on-ink);
  overflow: hidden;
  padding-block: clamp(3.5rem, 9vw, 7rem) clamp(4rem, 10vw, 8rem);
}
.hero__in { position: relative; z-index: 2; max-width: 46rem; }

.hero h1 {
  font-size: clamp(1.95rem, 5.2vw, 3.25rem);
  font-weight: 700;
  letter-spacing: -0.025em;
  line-height: 1.32;
  margin-bottom: 1.25rem;
  /* 中文标题折行时避免末行只剩一两个字（渐进增强，老浏览器忽略即可） */
  text-wrap: balance;
}
.hero h1 .hl {
  color: var(--blue);
  position: relative;
  white-space: nowrap;
}
/* 橙色"红笔"下划线 —— 呼应图纸上的标注 */
.hero h1 .hl::after {
  content: "";
  position: absolute;
  left: -2px; right: -2px; bottom: 0.06em;
  height: 3px;
  background: var(--orange);
  border-radius: 2px;
  transform: scaleX(0);
  transform-origin: left;
  animation: draw 0.7s cubic-bezier(0.65, 0, 0.35, 1) 0.85s forwards;
}
@keyframes draw { to { transform: scaleX(1); } }

.hero__sub {
  font-size: clamp(1.0625rem, 2.2vw, 1.375rem);
  color: var(--blue);
  font-weight: 500;
  margin-bottom: 1rem;
  letter-spacing: 0.01em;
}
.hero__desc {
  font-size: clamp(0.9375rem, 1.7vw, 1.0625rem);
  color: var(--on-ink-muted);
  line-height: 1.9;
  margin-bottom: 2.25rem;
  max-width: 38rem;
}
.hero__desc code {
  font-family: var(--mono);
  font-size: 0.9em;
  color: var(--blue);
  background: rgba(150, 222, 255, 0.1);
  padding: 0.15em 0.45em;
  border-radius: 2px;
}

.hero__actions { display: flex; flex-wrap: wrap; gap: 0.85rem; }
/* 窄屏上按钮各自占满一行：点击区域更大，视觉也更整齐 */
@media (max-width: 520px) {
  .hero__actions .btn { flex: 1 1 100%; }
}

/* Hero 右侧圆环装饰 */
.hero__rings {
  position: absolute;
  right: -14%;
  top: 50%;
  transform: translateY(-50%);
  width: min(58vw, 640px);
  aspect-ratio: 1;
  z-index: 1;
  pointer-events: none;
}
.hero__rings .ring:nth-child(1) { inset: 0; }
.hero__rings .ring:nth-child(2) { inset: 13%; border-color: rgba(255, 145, 77, 0.16); }
.hero__rings .ring:nth-child(3) { inset: 27%; border-style: dashed; }
.hero__rings .ring:nth-child(4) { inset: 41%; border-color: rgba(150, 222, 255, 0.3); }
@media (max-width: 900px) {
  .hero__rings { right: -32%; top: 12%; transform: none; width: 88vw; opacity: 0.5; }
}

/* ---------- 7. 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.55rem;
  padding: 0.85rem 1.6rem;
  border-radius: var(--radius);
  font-size: 0.9375rem;
  font-weight: 500;
  font-family: inherit;
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform 0.18s, background 0.2s, border-color 0.2s, color 0.2s, box-shadow 0.2s;
  text-decoration: none !important;
  line-height: 1.4;
}
.btn:hover { transform: translateY(-2px); }
.btn:active { transform: translateY(0); }

.btn--primary {
  background: var(--orange);
  color: #23120A;
  font-weight: 600;
  box-shadow: 0 4px 18px rgba(255, 145, 77, 0.26);
}
.btn--primary:hover { background: #FFA467; box-shadow: 0 8px 26px rgba(255, 145, 77, 0.34); }

.btn--ghost {
  border-color: rgba(150, 222, 255, 0.42);
  color: var(--blue);
}
.btn--ghost:hover { background: rgba(150, 222, 255, 0.1); border-color: var(--blue); }

.btn--solid-light {
  background: var(--blue-deep);
  color: #fff;
}
.btn--solid-light:hover { background: #095A8A; }
.btn--solid-light:hover { color: #fff; }

/* ---------- 8. 卡片 / 网格 ---------- */
.grid { display: grid; gap: var(--gap); }
.grid--2 { grid-template-columns: 1fr; }
.grid--3 { grid-template-columns: 1fr; }
.grid--4 { grid-template-columns: 1fr; }

@media (min-width: 680px) {
  .grid--2 { grid-template-columns: repeat(2, 1fr); }
  .grid--4 { grid-template-columns: repeat(2, 1fr); }
}
@media (min-width: 960px) {
  .grid--3 { grid-template-columns: repeat(3, 1fr); }
  .grid--4 { grid-template-columns: repeat(4, 1fr); }
}

.card {
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  padding: clamp(1.35rem, 2.6vw, 1.85rem);
  position: relative;
  transition: border-color 0.22s, box-shadow 0.22s, transform 0.22s;
}
.card:hover {
  border-color: var(--line-strong);
  box-shadow: 0 10px 32px rgba(22, 32, 46, 0.07);
  transform: translateY(-3px);
}
.card h3 {
  font-size: 1.0625rem;
  margin-bottom: 0.6rem;
  display: flex;
  align-items: baseline;
  gap: 0.6rem;
}
.card p { color: var(--text-muted); font-size: 0.9375rem; line-height: 1.85; }

/* 卡片编号（等宽，工程图索引感） */
.card__num {
  font-family: var(--mono);
  font-size: 0.75rem;
  color: var(--orange-deep);
  letter-spacing: 0.05em;
  flex: none;
}

/* 深色区块内的卡片 */
.section--ink .card {
  background: rgba(150, 222, 255, 0.045);
  border-color: rgba(150, 222, 255, 0.14);
}
.section--ink .card:hover {
  background: rgba(150, 222, 255, 0.075);
  border-color: rgba(150, 222, 255, 0.3);
  box-shadow: none;
}
.section--ink .card h3 { color: var(--on-ink); }
.section--ink .card p { color: var(--on-ink-muted); }
.section--ink .card__num { color: var(--orange); }

/* 痛点卡（暖色调，橙色警示） */
.card--pain {
  background: var(--paper-warm);
  border-color: #F5E0D0;
}
.card--pain .card__num { color: var(--orange-deep); }
.card--pain h3 { color: #7A3A12; }
.card--pain p { color: #8A6046; }

/* ---------- 9. 六步落地法 ---------- */
.steps { display: grid; gap: 0; counter-reset: step; }
@media (min-width: 960px) { .steps { grid-template-columns: repeat(6, 1fr); } }

.step {
  position: relative;
  padding: 1.5rem 1.1rem 1.5rem 0;
  border-top: 2px solid var(--line);
  counter-increment: step;
}
.step::before {
  content: "";
  position: absolute;
  top: -5px; left: 0;
  width: 8px; height: 8px;
  border-radius: 50%;
  background: var(--blue-deep);
}
.step:first-child::before { background: var(--orange); }
.step__num {
  font-family: var(--mono);
  font-size: 0.6875rem;
  letter-spacing: 0.14em;
  color: var(--text-soft);
  display: block;
  margin-bottom: 0.55rem;
}
.step h3 { font-size: 1rem; margin-bottom: 0.45rem; }
.step p { font-size: 0.875rem; color: var(--text-muted); line-height: 1.8; }

@media (min-width: 960px) {
  .step { padding-inline: 1rem 1.1rem; }
  .step:first-child { padding-left: 0; }
}

/* 六步落地法：业务顺序 vs 交付顺序 对照 */
.seq-compare {
  margin-top: clamp(2rem, 4vw, 3rem);
  padding: clamp(1.25rem, 3vw, 1.75rem);
  border: 1px solid rgba(150, 222, 255, 0.18);
  border-radius: var(--radius-lg);
  background: rgba(150, 222, 255, 0.04);
}
.seq-row {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 0.45rem 1.25rem;
  padding: 0.65rem 0;
}
.seq-row + .seq-row { border-top: 1px dashed rgba(150, 222, 255, 0.14); }
.seq-label {
  font-family: var(--mono);
  font-size: 0.6875rem;
  letter-spacing: 0.12em;
  color: var(--on-ink-muted);
  flex: none;
  min-width: 5rem;
}
.seq-chain {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.45rem;
  font-size: 0.9375rem;
  color: var(--on-ink);
}
.seq-chain i {
  font-style: normal;
  color: rgba(150, 222, 255, 0.45);
}
/* 被挪动的那一步 —— 用品牌橙标出 */
.seq-chain .moved {
  color: var(--orange);
  font-weight: 600;
}
.seq-note {
  margin-top: 1.1rem;
  padding-top: 1rem;
  border-top: 1px solid rgba(150, 222, 255, 0.12);
  font-size: 0.875rem;
  color: var(--on-ink-muted);
  line-height: 1.85;
}
.seq-note strong { color: var(--on-ink); }

/* ---------- 10. 对照（痛点 ↔ 解法） ---------- */
.compare { display: grid; gap: 0; border: 1px solid var(--line); border-radius: var(--radius-lg); overflow: hidden; }
@media (min-width: 760px) { .compare { grid-template-columns: 1fr 1fr; } }

.compare__col { padding: clamp(1.35rem, 2.6vw, 2rem); }
.compare__col--pain { background: var(--paper-warm); border-bottom: 1px solid #F5E0D0; }
.compare__col--fix { background: var(--paper); }
@media (min-width: 760px) {
  .compare__col--pain { border-bottom: none; border-right: 1px solid #F5E0D0; }
}

.compare__label {
  font-family: var(--mono);
  font-size: 0.6875rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  margin-bottom: 1rem;
  display: block;
}
.compare__col--pain .compare__label { color: var(--orange-deep); }
.compare__col--fix .compare__label { color: var(--blue-deep); }

.tick { list-style: none; margin: 0; padding: 0; }
.tick li {
  position: relative;
  padding-left: 1.5rem;
  margin-bottom: 0.8rem;
  font-size: 0.9375rem;
  line-height: 1.8;
  color: var(--text-muted);
}
.tick li:last-child { margin-bottom: 0; }
.tick li::before {
  content: "";
  position: absolute;
  left: 0; top: 0.62em;
  width: 7px; height: 7px;
  border-radius: 50%;
}
.compare__col--pain .tick li::before { background: var(--orange-deep); opacity: 0.5; }
.compare__col--fix .tick li::before { background: var(--blue-deep); }
.compare__col--fix .tick li { color: var(--text); }

/* ---------- 11. 对比三列（和别人的差别） ---------- */
.vs { display: grid; gap: var(--gap); }
@media (min-width: 860px) { .vs { grid-template-columns: repeat(3, 1fr); } }

.vs__item {
  border-left: 2px solid var(--line-strong);
  padding-left: 1.25rem;
}
.vs__item h3 {
  font-size: 1rem;
  color: var(--text-soft);
  font-weight: 500;
  margin-bottom: 0.7rem;
  text-decoration: line-through;
  text-decoration-color: rgba(135, 148, 166, 0.5);
  text-decoration-thickness: 1px;
}
.vs__item p { font-size: 0.9375rem; color: var(--text-muted); line-height: 1.85; }

/* ---------- 12. 联系我们 / 二维码 ---------- */
.contact-grid { display: grid; gap: var(--gap); align-items: start; }
@media (min-width: 760px) { .contact-grid { grid-template-columns: 1fr auto; } }

.qr-row { display: flex; gap: 1.5rem; flex-wrap: wrap; }
.qr { text-align: center; }
.qr img {
  width: 132px; height: 132px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #fff;
  padding: 5px;
}
.qr span {
  display: block;
  margin-top: 0.6rem;
  font-size: 0.8125rem;
  color: var(--text-soft);
  font-family: var(--mono);
  letter-spacing: 0.04em;
}

.contact-line {
  display: flex;
  align-items: baseline;
  gap: 0.9rem;
  padding: 0.85rem 0;
  border-bottom: 1px solid var(--line);
  font-size: 1rem;
}
.contact-line__k {
  font-family: var(--mono);
  font-size: 0.6875rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--text-soft);
  flex: none;
  width: 4.5rem;
}
.contact-line__v { font-weight: 500; }
.contact-line__v a { color: var(--text); }
.contact-line__v a:hover { color: var(--blue-deep); }

/* ---------- 13. CTA 条 ---------- */
.cta-bar {
  position: relative;
  overflow: hidden;
  background: linear-gradient(150deg, var(--ink-900) 0%, var(--ink-800) 70%, var(--ink-700) 100%);
  color: var(--on-ink);
  border-radius: var(--radius-lg);
  padding: clamp(2rem, 5vw, 3.25rem);
  text-align: center;
}
.cta-bar h2 {
  font-size: clamp(1.3rem, 3vw, 1.9rem);
  margin-bottom: 0.75rem;
  position: relative;
  z-index: 2;
}
.cta-bar p {
  color: var(--on-ink-muted);
  margin-bottom: 1.75rem;
  position: relative;
  z-index: 2;
}
.cta-bar .btn { position: relative; z-index: 2; }
.cta-bar .ring { z-index: 1; }

/* ---------- 14. 页脚 ---------- */
.ftr {
  background: var(--ink-900);
  color: var(--on-ink-muted);
  border-top: 1px solid rgba(150, 222, 255, 0.12);
  padding-block: clamp(2.5rem, 5vw, 3.5rem) 1.75rem;
  font-size: 0.875rem;
}
.ftr__top {
  display: grid;
  gap: 2rem;
  margin-bottom: 2.25rem;
}
@media (min-width: 760px) { .ftr__top { grid-template-columns: 1.4fr 1fr 1fr; } }

.ftr__logo { height: 30px; width: auto; margin-bottom: 1rem; }
.ftr__about { line-height: 1.9; max-width: 26rem; }

.ftr h4 {
  font-size: 0.75rem;
  font-family: var(--mono);
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--blue);
  margin-bottom: 0.9rem;
  font-weight: 500;
}
.ftr ul { list-style: none; margin: 0; padding: 0; }
.ftr li { margin-bottom: 0.55rem; }
.ftr a { color: var(--on-ink-muted); }
.ftr a:hover { color: var(--blue); }

.ftr__bottom {
  border-top: 1px solid rgba(150, 222, 255, 0.1);
  padding-top: 1.75rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: 0.6rem;
  font-size: 0.875rem;
  line-height: 1.7;
  color: var(--on-ink-muted);
}
/* ICP 备案号是法定必须公开展示的，做成清晰可读而非装饰性灰字 */
.ftr__bottom a {
  color: var(--on-ink);
  text-decoration: underline;
  text-decoration-color: rgba(150, 222, 255, 0.45);
  text-underline-offset: 3px;
}
.ftr__bottom a:hover {
  color: var(--blue);
  text-decoration-color: var(--blue);
}

/* ---------- 15. 滚动显现（JS 启用，无 JS 时直接可见） ---------- */
.js .reveal {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 0.6s cubic-bezier(0.22, 1, 0.36, 1),
              transform 0.6s cubic-bezier(0.22, 1, 0.36, 1);
}
.js .reveal.is-in { opacity: 1; transform: none; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .js .reveal { opacity: 1; transform: none; transition: none; }
  .hero h1 .hl::after { animation: none; transform: scaleX(1); }
  .btn:hover, .card:hover { transform: none; }
}

/* 首屏错峰入场 */
.js .hero .anim { opacity: 0; animation: rise 0.7s cubic-bezier(0.22, 1, 0.36, 1) forwards; }
.js .hero .anim:nth-child(1) { animation-delay: 0.05s; }
.js .hero .anim:nth-child(2) { animation-delay: 0.18s; }
.js .hero .anim:nth-child(3) { animation-delay: 0.31s; }
.js .hero .anim:nth-child(4) { animation-delay: 0.44s; }
@keyframes rise { from { opacity: 0; transform: translateY(16px); } to { opacity: 1; transform: none; } }
@media (prefers-reduced-motion: reduce) { .js .hero .anim { opacity: 1; animation: none; } }

/* ---------- 16. 工具类 ---------- */
.mt-0 { margin-top: 0 !important; }
.mt-2 { margin-top: 2rem; }
.mt-3 { margin-top: 3rem; }
.center { text-align: center; }
.sr-only {
  position: absolute; width: 1px; height: 1px;
  padding: 0; margin: -1px; overflow: hidden;
  clip: rect(0, 0, 0, 0); white-space: nowrap; border: 0;
}

/* 打印 */
@media print {
  .hdr, .nav-toggle, .cta-bar .btn { display: none; }
  .hero, .section--ink, .ftr { background: #fff !important; color: #000 !important; }
  .bg-grid, .ring { display: none; }
}