/* ==========================================================================
   讯灵AI 招商落地页 · 样式表
   设计约定：移动优先 → 逐级增强；主色红 #0C48F0，背景白，符合品牌调性
   断点：640 / 768 / 1024 / 1200
   ========================================================================== */

/* 1. 变量与重置 ---------------------------------------------------------- */
:root {
  --brand: #0C48F0;
  --brand-dark: #0A3AC4;
  --brand-soft: #E8EEFE;
  --ink: #16181D;
  --ink-2: #3D4450;
  --muted: #6B7382;
  --bg: #FFFFFF;
  --surface: #F7F8FA;
  --line: #E7E9EF;
  --white: #FFFFFF;

  --radius: 14px;
  --radius-lg: 20px;
  --shadow-sm: 0 2px 8px rgba(16, 24, 40, .06);
  --shadow: 0 10px 30px rgba(16, 24, 40, .08);
  --shadow-lg: 0 24px 60px rgba(16, 24, 40, .12);

  --maxw: 1200px;
  --header-h: 60px;

  --font: "PingFang SC", "Microsoft YaHei", "微软雅黑", "Hiragino Sans GB",
          "Source Han Sans SC", "Noto Sans CJK SC", system-ui, -apple-system,
          "Segoe UI", Roboto, sans-serif;
}

*, *::before, *::after { box-sizing: border-box; }

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-h) + 16px); /* 锚点不被固定导航遮挡 */
}

body {
  margin: 0;
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.7;
  color: var(--ink-2);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
}

img, svg { max-width: 100%; display: block; }
ul, ol { margin: 0; padding: 0; list-style: none; }
a { color: inherit; text-decoration: none; }
button { font: inherit; cursor: pointer; }

h1, h2, h3 {
  margin: 0 0 .6em;
  color: var(--ink);
  line-height: 1.28;
  letter-spacing: -.01em;
}
h1 { font-size: clamp(1.9rem, 6.4vw, 3.25rem); font-weight: 800; }
h2 { font-size: clamp(1.4rem, 4.2vw, 2.1rem); font-weight: 800; }
h3 { font-size: 1.075rem; font-weight: 700; }
p { margin: 0 0 1em; }
strong { color: var(--ink); font-weight: 700; }

:focus-visible {
  outline: 3px solid var(--brand);
  outline-offset: 2px;
  border-radius: 4px;
}

.skip-link {
  position: absolute; left: -9999px; top: 0; z-index: 999;
  background: var(--brand); color: #fff; padding: 10px 16px; border-radius: 0 0 8px 0;
}
.skip-link:focus { left: 0; }

/* 2. 布局工具 ------------------------------------------------------------ */
.container {
  width: 100%;
  max-width: var(--maxw);
  margin-inline: auto;
  padding-inline: 20px;
}
.container--narrow { max-width: 820px; }

.section { padding: clamp(48px, 9vw, 88px) 0; }
.section--surface { background: var(--surface); }
.section--brand {
  background: linear-gradient(135deg, var(--brand) 0%, var(--brand-dark) 100%);
  color: #fff;
}
.section--brand h2, .section--brand h3 { color: #fff; }

.section__head { max-width: 760px; margin-bottom: clamp(28px, 5vw, 48px); }
.section__lead { color: var(--muted); font-size: 1.02rem; margin-bottom: 0; }

.eyebrow {
  display: inline-block;
  margin: 0 0 10px;
  color: var(--brand);
  font-size: .82rem;
  font-weight: 800;
  letter-spacing: .14em;
  text-transform: uppercase;
}
.eyebrow--light { color: #BFD0FF; }

.note { font-size: .84rem; color: var(--muted); margin-top: 20px; }

/* 3. 按钮 ---------------------------------------------------------------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-height: 46px;
  padding: 0 22px;
  border: 1px solid transparent;
  border-radius: 999px;
  font-size: .96rem;
  font-weight: 700;
  transition: transform .18s ease, box-shadow .18s ease, background .18s ease, color .18s ease;
  white-space: nowrap;
}
.btn--sm { min-height: 38px; padding: 0 16px; font-size: .88rem; }
.btn--block { width: 100%; }
.btn--primary { background: var(--brand); color: #fff; box-shadow: 0 8px 20px rgba(12, 72, 240, .26); }
.btn--primary:hover { background: var(--brand-dark); transform: translateY(-2px); }
.btn--ghost { background: #fff; color: var(--brand); border-color: #C5D3FD; }
.btn--ghost:hover { border-color: var(--brand); transform: translateY(-2px); }
.btn--light { background: #fff; color: var(--brand); }
.btn--light:hover { transform: translateY(-2px); box-shadow: var(--shadow); }

/* 4. 顶栏与导航 ---------------------------------------------------------- */
.topbar { background: var(--ink); color: #D7DAE1; font-size: .82rem; }
.topbar__inner {
  display: flex; align-items: center; justify-content: space-between;
  gap: 12px; min-height: 36px;
}
.topbar__text a { color: #fff; font-weight: 700; }
.topbar__link { color: #A9C0FF; font-weight: 700; }
.topbar__link:hover { text-decoration: underline; }

.header {
  position: sticky; top: 0; z-index: 50;
  background: rgba(255, 255, 255, .92);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid transparent;
  transition: border-color .2s ease, box-shadow .2s ease;
}
.header.is-stuck { border-bottom-color: var(--line); box-shadow: var(--shadow-sm); }
.header__inner {
  display: flex; align-items: center; justify-content: space-between;
  gap: 16px; min-height: var(--header-h);
}

.logo { display: inline-flex; align-items: center; }
.logo__img {
  display: block;
  height: 36px;          /* 与导航高度匹配，宽度按图片比例自动计算 */
  width: auto;
}
.logo__img--footer {
  /* 页脚深色底上垫白底圆角，保证品牌蓝有足够对比度 */
  box-sizing: content-box;
  height: 28px;
  padding: 6px 12px;
  background: #fff;
  border-radius: 9px;
}

@media (max-width: 767px) {
  .logo__img { height: 30px; }
}

.nav {
  position: fixed; inset: calc(var(--header-h) + 36px) 0 auto 0;
  display: none;
  flex-direction: column; gap: 4px;
  padding: 16px 20px 24px;
  background: #fff;
  border-bottom: 1px solid var(--line);
  box-shadow: var(--shadow);
}
.nav.is-open { display: flex; }
.nav ul { display: flex; flex-direction: column; gap: 2px; }
.nav a:not(.btn) {
  display: block; padding: 12px 4px;
  border-bottom: 1px solid var(--line);
  font-weight: 600; color: var(--ink);
}
.nav a:not(.btn):hover, .nav a.is-active { color: var(--brand); }
.nav__cta { margin-top: 14px; }

/* 导航内代理电话（选择器特异性需覆盖 .nav a:not(.btn)） */
.nav a.nav__tel {
  display: inline-flex; align-items: center; gap: 7px;
  white-space: nowrap; color: var(--ink); font-weight: 800;
}
.nav a.nav__tel:hover { color: var(--brand); }
.nav__tel svg { flex: none; color: var(--brand); }
.nav__tel-tag {
  padding: 2px 8px; border-radius: 999px;
  background: var(--brand-soft); color: var(--brand);
  font-size: .7rem; font-weight: 700;
}

.menu-toggle {
  display: grid; gap: 4px; place-content: center;
  width: 42px; height: 42px;
  background: #fff; border: 1px solid var(--line); border-radius: 10px;
}
.menu-toggle span {
  display: block; width: 18px; height: 2px;
  background: var(--ink); border-radius: 2px;
  transition: transform .2s ease, opacity .2s ease;
}
.menu-toggle[aria-expanded="true"] span:nth-child(1) { transform: translateY(6px) rotate(45deg); }
.menu-toggle[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.menu-toggle[aria-expanded="true"] span:nth-child(3) { transform: translateY(-6px) rotate(-45deg); }

/* 5. Hero ---------------------------------------------------------------- */
.hero { padding: clamp(36px, 7vw, 72px) 0 clamp(40px, 7vw, 76px); background:
  radial-gradient(900px 420px at 88% -8%, #E8EEFE 0%, transparent 60%),
  radial-gradient(700px 380px at 4% 8%, #F2F6FF 0%, transparent 62%); }
.hero__grid { display: grid; gap: 36px; }
.hero__lead { font-size: 1.03rem; color: var(--ink-2); max-width: 34em; }
.hl { color: var(--brand); }
.hero__actions { display: flex; flex-wrap: wrap; gap: 12px; margin: 22px 0 18px; }
.hero__tel {
  display: inline-flex; align-items: center; gap: 6px; align-self: center;
  font-size: .92rem; font-weight: 600; color: var(--muted);
  border-bottom: 1px dashed var(--line);
  transition: color .18s ease, border-color .18s ease;
}
.hero__tel svg { flex: none; color: var(--brand); }
.hero__tel b { color: var(--ink); font-weight: 800; }
.hero__tel:hover { color: var(--brand); border-bottom-color: var(--brand); }
.hero__meta { display: grid; gap: 6px; font-size: .88rem; color: var(--muted); }
.hero__meta li { padding-left: 20px; position: relative; }
.hero__meta li::before {
  content: "✓"; position: absolute; left: 0; top: 0;
  color: var(--brand); font-weight: 800;
}

/* AI 对话示意卡片（纯 CSS，无外链资源） */
.hero__visual { position: relative; padding-bottom: 12px; }
.chat-card {
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  background: #fff;
  box-shadow: var(--shadow-lg);
  overflow: hidden;
}
.chat-card__bar { display: flex; gap: 6px; padding: 12px 14px; background: var(--surface); border-bottom: 1px solid var(--line); }
.chat-card__bar i { width: 9px; height: 9px; border-radius: 50%; background: #D8DCE5; }
.chat-card__bar i:first-child { background: #A9C0FF; }
.chat-card__body { padding: 18px; }
.chat-q {
  margin: 0 0 14px; padding: 10px 14px;
  background: var(--surface); border-radius: 12px 12px 12px 4px;
  font-size: .92rem; color: var(--ink);
}
.chat-a {
  margin: 0; padding: 14px;
  background: var(--brand-soft); border-radius: 12px 12px 4px 12px;
  font-size: .92rem; color: var(--ink-2);
}
.chat-a__brand { display: inline-block; margin: 6px 0; color: var(--brand); font-weight: 800; }
.chat-typing { display: flex; gap: 5px; padding: 10px 14px 0; }
.chat-typing span {
  width: 6px; height: 6px; border-radius: 50%; background: #C9CFDA;
  animation: blink 1.2s infinite ease-in-out;
}
.chat-typing span:nth-child(2) { animation-delay: .18s; }
.chat-typing span:nth-child(3) { animation-delay: .36s; }
@keyframes blink { 0%, 60%, 100% { opacity: .3; } 30% { opacity: 1; } }

.float-card {
  position: absolute;
  padding: 10px 14px;
  background: #fff; border: 1px solid var(--line);
  border-radius: 12px; box-shadow: var(--shadow);
  display: grid; gap: 2px; line-height: 1.3;
}
.float-card b { font-size: .84rem; color: var(--ink); }
.float-card span { font-size: .74rem; color: var(--muted); }
.float-card--1 { right: 4px; bottom: 74px; }
.float-card--2 { left: -6px; top: -10px; }

/* 数据条 */
.stats {
  display: grid; grid-template-columns: repeat(2, 1fr); gap: 14px;
  margin-top: 34px; padding: 20px;
  background: #fff; border: 1px solid var(--line);
  border-radius: var(--radius-lg); box-shadow: var(--shadow-sm);
}
.stats li { text-align: center; }
.stats b { display: block; font-size: clamp(1.4rem, 5vw, 1.9rem); font-weight: 800; color: var(--brand); line-height: 1.15; }
.stats span { font-size: .8rem; color: var(--muted); }

/* 6. 对比模块 ------------------------------------------------------------ */
.compare { display: grid; gap: 14px; margin-bottom: 32px; }
.compare__col {
  padding: 22px; border-radius: var(--radius); border: 1px solid var(--line); background: #fff;
}
.compare__col--old { background: var(--surface); }
.compare__col--new { border-color: #C5D3FD; background: #FCFDFF; box-shadow: var(--shadow-sm); }
.compare__col h3 { margin-bottom: 12px; }
.compare__col--new h3 { color: var(--brand); }
.compare__col li { padding-left: 20px; position: relative; font-size: .93rem; margin-bottom: 6px; }
.compare__col li::before { content: "·"; position: absolute; left: 6px; font-weight: 900; }
.compare__col--new li::before { content: "✓"; color: var(--brand); font-size: .8rem; left: 0; }
.compare__arrow { display: none; }

/* 7. 卡片 ---------------------------------------------------------------- */
.cards { display: grid; gap: 16px; }
.card {
  padding: 24px; border-radius: var(--radius);
  background: #fff; border: 1px solid var(--line);
  transition: transform .2s ease, box-shadow .2s ease;
}
.card:hover { transform: translateY(-4px); box-shadow: var(--shadow); }
.card p { margin: 0; font-size: .93rem; color: var(--muted); }
.card__icon {
  display: grid; place-items: center;
  width: 44px; height: 44px; margin-bottom: 14px;
  border-radius: 12px; background: var(--brand-soft);
  color: var(--brand); font-weight: 800; font-size: 1rem;
}

/* 双引擎 */
.engines { display: grid; gap: 18px; }
.engine {
  padding: 26px; border-radius: var(--radius-lg);
  background: #fff; border: 1px solid var(--line); box-shadow: var(--shadow-sm);
}
.engine--alt { background: linear-gradient(160deg, #fff 0%, #F7F9FF 100%); border-color: #D3DEFD; }
.engine__tag {
  display: inline-block; margin-bottom: 10px; padding: 4px 12px;
  border-radius: 999px; background: var(--brand); color: #fff;
  font-size: .74rem; font-weight: 800; letter-spacing: .08em;
}
.engine--alt .engine__tag { background: var(--ink); }
.engine__desc { color: var(--muted); font-size: .95rem; }

.ticks li { position: relative; padding-left: 24px; margin-bottom: 8px; font-size: .93rem; }
.ticks li::before {
  content: "✓"; position: absolute; left: 0; top: 0;
  color: var(--brand); font-weight: 900; font-size: .85rem;
}
.ticks--sm li { font-size: .9rem; margin-bottom: 7px; }

/* 8. 定价 ---------------------------------------------------------------- */
.pricing { align-items: stretch; }
.plan {
  display: flex; flex-direction: column;
  padding: 26px; border-radius: var(--radius-lg);
  background: #fff; border: 1px solid var(--line);
  transition: transform .2s ease, box-shadow .2s ease;
}
.plan:hover { transform: translateY(-4px); box-shadow: var(--shadow); }
.plan--featured {
  border-color: var(--brand);
  box-shadow: 0 14px 40px rgba(12, 72, 240, .14);
  position: relative;
}
.plan__badge {
  position: absolute; top: -12px; left: 26px;
  padding: 4px 12px; border-radius: 999px;
  background: var(--brand); color: #fff; font-size: .74rem; font-weight: 800;
}
.plan__for { font-size: .86rem; color: var(--muted); margin-bottom: 10px; }
.plan__price { font-size: 1.85rem; font-weight: 800; color: var(--ink); line-height: 1.1; margin-bottom: 16px; }
.plan__price small { font-size: .8rem; font-weight: 600; color: var(--muted); margin-left: 4px; }
.plan .ticks { margin-bottom: 20px; flex: 1; }
.plan__price { margin-bottom: 4px; }
.plan__origin { margin: 0 0 4px; font-size: .84rem; color: var(--muted); }
.plan__include { margin: 0 0 16px; font-size: .8rem; color: var(--muted); }

/* 8.5 报价对比表 ---------------------------------------------------------- */
.spec { margin-top: clamp(36px, 6vw, 60px); }
.spec__title { text-align: center; }
.spec__hint { text-align: center; font-size: .84rem; color: var(--muted); margin-bottom: 18px; }
.table-wrap {
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #fff;
  box-shadow: var(--shadow-sm);
}
.spec-table { width: 100%; min-width: 760px; border-collapse: collapse; font-size: .9rem; }
.spec-table thead th {
  padding: 13px 16px; text-align: left; white-space: nowrap;
  background: var(--ink); color: #fff; font-weight: 700; font-size: .88rem;
}
.spec-table tbody th,
.spec-table tbody td {
  padding: 13px 16px; text-align: left; vertical-align: top;
  border-bottom: 1px solid var(--line);
}
.spec-table tbody th { min-width: 260px; font-weight: 700; color: var(--ink); }
.spec-table tbody td { white-space: nowrap; font-weight: 600; color: var(--ink-2); }
.spec-table tbody tr:last-child th,
.spec-table tbody tr:last-child td { border-bottom: 0; }
.spec-table tbody tr:hover th,
.spec-table tbody tr:hover td { background: #F8FAFF; }
.spec-group th {
  padding: 9px 16px;
  background: var(--brand-soft); color: var(--brand);
  font-weight: 800; font-size: .88rem; letter-spacing: .04em;
}
.spec__desc {
  display: block; margin-top: 5px;
  font-weight: 400; font-size: .78rem; line-height: 1.6;
  color: var(--muted); white-space: normal; max-width: 54em;
}
.spec__notes { margin: 18px 0 0; display: grid; gap: 7px; }
.spec__notes li {
  position: relative; padding-left: 18px;
  font-size: .82rem; line-height: 1.6; color: var(--muted);
}
.spec__notes li::before { content: "※"; position: absolute; left: 0; color: var(--brand); }
.spec__owner { margin: 14px 0 0; text-align: center; font-size: .8rem; color: var(--muted); }

/* 9. 监测 ---------------------------------------------------------------- */
.monitor__grid { display: grid; gap: 32px; }
.chart-card {
  padding: 20px; border-radius: var(--radius-lg);
  background: #fff; border: 1px solid var(--line); box-shadow: var(--shadow);
}
.chart-card__head {
  display: flex; align-items: center; justify-content: space-between;
  margin-bottom: 18px; font-size: .88rem; font-weight: 700; color: var(--ink);
}
.chart-card__legend { display: inline-flex; align-items: center; gap: 6px; font-weight: 600; color: var(--muted); }
.dot { width: 8px; height: 8px; border-radius: 50%; background: var(--brand); }
.bars { display: flex; align-items: flex-end; gap: 8px; height: 170px; }
.bars i {
  flex: 1; height: var(--h);
  border-radius: 6px 6px 0 0;
  background: linear-gradient(180deg, #5B87FF 0%, var(--brand) 100%);
  animation: grow .9s cubic-bezier(.2, .8, .2, 1) both;
}
.bars i:nth-child(2n) { background: linear-gradient(180deg, #A9C0FF 0%, #3B6BFF 100%); }
@keyframes grow { from { height: 4%; opacity: .4; } to { opacity: 1; } }
.chart-card__foot { display: flex; justify-content: space-between; margin-top: 10px; font-size: .76rem; color: var(--muted); }

/* 10. 行业标签 ----------------------------------------------------------- */
.chips { display: flex; flex-wrap: wrap; gap: 10px; }
.chips li {
  padding: 8px 16px; border-radius: 999px;
  background: #fff; border: 1px solid var(--line);
  font-size: .9rem; color: var(--ink-2); font-weight: 600;
  transition: background .18s ease, color .18s ease, border-color .18s ease;
}
.chips li:hover { background: var(--brand); border-color: var(--brand); color: #fff; }

/* 11. 合作流程 ----------------------------------------------------------- */
.steps { margin-top: 40px; }
.steps__title { text-align: center; margin-bottom: 20px; }
.steps ol { display: grid; gap: 12px; counter-reset: step; }
.steps li {
  counter-increment: step;
  display: grid; gap: 2px;
  padding: 16px 18px 16px 52px;
  position: relative;
  background: #fff; border: 1px solid var(--line); border-radius: var(--radius);
}
.steps li::before {
  content: counter(step);
  position: absolute; left: 16px; top: 16px;
  display: grid; place-items: center;
  width: 24px; height: 24px; border-radius: 50%;
  background: var(--brand); color: #fff; font-size: .78rem; font-weight: 800;
}
.steps b { color: var(--ink); }
.steps span { font-size: .86rem; color: var(--muted); }

/* 12. FAQ ---------------------------------------------------------------- */
.accordion { display: grid; gap: 10px; }
.acc { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); overflow: hidden; }
.acc__q {
  width: 100%; display: flex; align-items: center; justify-content: space-between; gap: 12px;
  padding: 16px 18px; background: none; border: 0; text-align: left;
  font-weight: 700; color: var(--ink); font-size: .98rem;
}
.acc__q i {
  flex: none; width: 18px; height: 18px; position: relative;
  border-radius: 50%; background: var(--brand-soft);
}
.acc__q i::before, .acc__q i::after {
  content: ""; position: absolute; inset: 50% 4px auto 4px; height: 2px;
  background: var(--brand); transform: translateY(-50%); transition: transform .2s ease;
}
.acc__q i::after { transform: translateY(-50%) rotate(90deg); }
.acc__q[aria-expanded="true"] i::after { transform: translateY(-50%) rotate(0deg); }
.acc__a { display: none; padding: 0 18px 16px; }
.acc__a.is-open { display: block; }
.acc__a p { margin: 0; font-size: .93rem; color: var(--muted); }

/* 13. 联系区 ------------------------------------------------------------- */
.contact__grid { display: grid; gap: 32px; }
.contact__copy p { color: rgba(255, 255, 255, .88); }
.contact__list { display: grid; gap: 10px; margin-top: 8px; }
.contact__list li {
  display: flex; flex-wrap: wrap; gap: 10px; align-items: baseline;
  padding-bottom: 10px; border-bottom: 1px solid rgba(255, 255, 255, .22);
}
.contact__list span { min-width: 68px; color: rgba(255, 255, 255, .7); font-size: .86rem; }
.contact__list a { font-weight: 800; font-size: 1.05rem; }
.contact__list a:hover { text-decoration: underline; }
.contact__hint {
  font-style: normal; font-size: .78rem; font-weight: 700;
  padding: 2px 9px; margin-left: 2px;
  color: #fff; background: rgba(255, 255, 255, .16);
  border-radius: 999px; white-space: nowrap;
}
.link-btn {
  background: none; border: 0; padding: 0;
  color: #fff; font-weight: 800; font-size: 1.05rem; text-align: left;
}
.link-btn:hover { text-decoration: underline; }

.form {
  display: grid; grid-template-columns: 1fr; gap: 14px;
  padding: clamp(20px, 4vw, 30px);
  background: #fff; border-radius: var(--radius-lg); box-shadow: var(--shadow-lg);
}
.field { display: grid; gap: 6px; }
.field label { font-size: .86rem; font-weight: 700; color: var(--ink); }
.field input, .field select, .field textarea {
  width: 100%; min-height: 46px; padding: 11px 14px;
  font: inherit; font-size: .95rem; color: var(--ink);
  background: #fff; border: 1px solid var(--line); border-radius: 10px;
  transition: border-color .18s ease, box-shadow .18s ease;
}
.field textarea { min-height: 92px; resize: vertical; }
.field input:focus, .field select:focus, .field textarea:focus {
  outline: none; border-color: var(--brand); box-shadow: 0 0 0 3px rgba(12, 72, 240, .12);
}
.field.is-invalid input, .field.is-invalid select { border-color: var(--brand); background: #F8FAFF; }
.field__err { margin: 0; font-size: .78rem; color: var(--brand); min-height: 1em; }
.form__tip { margin: 0; font-size: .78rem; color: var(--muted); text-align: center; }
.form__result { margin: 0; font-size: .88rem; font-weight: 700; text-align: center; color: var(--brand); }
.form__result:empty { display: none; }

/* 14. 页脚 --------------------------------------------------------------- */
.footer { background: var(--ink); color: #A8AEBB; padding: 40px 0 28px; font-size: .88rem; }
.footer__inner { display: grid; gap: 18px; text-align: center; }
.footer__brand { display: grid; gap: 10px; justify-items: center; }
.footer__brand p { margin: 0; color: #fff; font-weight: 700; }
.footer__nav { display: flex; flex-wrap: wrap; gap: 16px; justify-content: center; }
.footer__nav a { color: #C9CEDA; }
.footer__nav a:hover { color: #fff; }
.footer__copy { margin: 0; font-size: .8rem; }
.footer__copy a { color: #fff; font-weight: 700; }
.footer__copy a:hover { text-decoration: underline; }

/* 极窄屏：隐藏顶栏右侧次要链接，避免与热线号码挤在一行 */
@media (max-width: 430px) {
  .topbar__link { display: none; }
}

/* 15. 返回顶部 ----------------------------------------------------------- */
.to-top {
  position: fixed; right: 16px; bottom: 16px; z-index: 40;
  width: 44px; height: 44px; border: 0; border-radius: 50%;
  background: var(--brand); color: #fff; font-size: 1.1rem; font-weight: 800;
  box-shadow: var(--shadow);
  opacity: 0; visibility: hidden; transform: translateY(8px);
  transition: opacity .2s ease, transform .2s ease, visibility .2s ease;
}
.to-top.is-visible { opacity: 1; visibility: visible; transform: translateY(0); }

/* 16. 滚动入场动画 ------------------------------------------------------- */
[data-reveal] { opacity: 0; transform: translateY(18px); transition: opacity .6s ease, transform .6s ease; }
[data-reveal].is-visible { opacity: 1; transform: none; }

/* 17. 断点：≥640px ------------------------------------------------------- */
@media (min-width: 640px) {
  .stats { grid-template-columns: repeat(4, 1fr); gap: 10px; }
  .cards--3 { grid-template-columns: repeat(2, 1fr); }
  .form { grid-template-columns: repeat(2, 1fr); }
  .field--full { grid-column: 1 / -1; }
  .form > .btn, .form__tip, .form__result { grid-column: 1 / -1; }
}

/* 18. 断点：≥768px ------------------------------------------------------- */
@media (min-width: 768px) {
  :root { --header-h: 68px; }
  .compare { grid-template-columns: 1fr auto 1fr; align-items: center; }
  .compare__arrow {
    display: grid; place-items: center;
    width: 42px; height: 42px; border-radius: 50%;
    background: var(--brand); color: #fff; font-weight: 800;
    font-size: 1.1rem;
  }
  .engines { grid-template-columns: repeat(2, 1fr); }
  .cards--3 { grid-template-columns: repeat(3, 1fr); }
  .pricing { grid-template-columns: repeat(3, 1fr); }
  .monitor__grid { grid-template-columns: 1fr 1fr; align-items: center; }
  .steps ol { grid-template-columns: repeat(5, 1fr); }
  .steps li { grid-template-columns: 1fr; }
  .contact__grid { grid-template-columns: 1fr 1.05fr; gap: 44px; align-items: start; }
  .footer__inner { grid-template-columns: auto 1fr; text-align: left; align-items: center; }
  .footer__brand { justify-items: start; }
  .footer__nav { justify-content: flex-end; }
  .footer__copy { grid-column: 1 / -1; }
  .to-top { right: 24px; bottom: 24px; }
}

/* 19. 断点：≥1024px ------------------------------------------------------ */
@media (min-width: 1024px) {
  .menu-toggle { display: none; }
  .nav {
    position: static; inset: auto;
    display: flex; flex-direction: row; align-items: center; gap: 26px;
    padding: 0; background: none; border: 0; box-shadow: none;
  }
  .nav ul { flex-direction: row; gap: 22px; }
  .nav a:not(.btn) { padding: 6px 0; border: 0; font-size: .93rem; font-weight: 600; }
  .nav a.is-active { color: var(--brand); }
  .nav__cta { margin-top: 0; }
  .hero__grid { grid-template-columns: 1.05fr .95fr; gap: 56px; align-items: center; }
  .hero { padding-top: clamp(56px, 6vw, 88px); }
  .float-card--1 { right: -18px; bottom: 96px; }
  .float-card--2 { left: -22px; top: 6px; }
}

/* 20. 断点：≥1200px ------------------------------------------------------ */
@media (min-width: 1200px) {
  .container { padding-inline: 24px; }
  .hero__lead { font-size: 1.08rem; }
}

/* 21. 降低动效偏好 / 打印 ------------------------------------------------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: .001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .001ms !important;
  }
  [data-reveal] { opacity: 1; transform: none; }
}

@media print {
  .topbar, .header, .to-top, .hero__visual { display: none; }
  body { color: #000; }
  .section--brand { background: none; color: #000; }
}