/* ==========================================================================
   渊博信息科技（苏州）有限公司 — 官网样式
   风格：瑞士国际主义（网格 / 无衬线 / 黑白 + 单一红）
   字体使用系统栈，不加载任何外部字体。
   ========================================================================== */

:root {
  --bg:        #ffffff;
  --ink:       #0d0d0d;
  --ink-2:     #6b6b6b;
  --ink-3:     #9a9a9a;
  --line:      #0d0d0d;
  --line-soft: #e2e2e2;
  --red:       #e1261c;

  --sans: "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB",
          "Microsoft YaHei", "Noto Sans SC", sans-serif;

  --wrap: 1200px;
  --pad: 40px;
  --head-h: 72px;
}

* { box-sizing: border-box; }

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--head-h) + 16px);
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.7;
  font-variant-numeric: tabular-nums;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

a { color: inherit; text-decoration: none; }

::selection { background: var(--red); color: #fff; }

.wrap {
  max-width: var(--wrap);
  margin: 0 auto;
  padding: 0 var(--pad);
}

/* ---------- 顶部 ---------- */

.site-head {
  position: sticky;
  top: 0;
  z-index: 20;
  background: var(--bg);
  border-bottom: 1px solid var(--line);
}

.head-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  height: var(--head-h);
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
}

.brand-cn {
  font-size: 1.375rem;
  font-weight: 700;
  letter-spacing: .02em;
}

.brand-rule {
  width: 1px;
  height: 18px;
  background: var(--line-soft);
}

.brand-en {
  font-size: 10px;
  font-weight: 700;
  letter-spacing: .22em;
  color: var(--ink-3);
}

.nav {
  display: flex;
  gap: 32px;
  font-size: 13px;
  font-weight: 600;
  letter-spacing: .05em;
}

.nav a {
  padding-bottom: 3px;
  border-bottom: 2px solid transparent;
  transition: border-color .2s ease, color .2s ease;
}

.nav a:hover { border-bottom-color: var(--red); }

.lang {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: .06em;
}

.lang-btn {
  margin: 0;
  padding: 0 0 3px;
  font: inherit;
  color: var(--ink-3);
  background: none;
  border: 0;
  border-bottom: 2px solid transparent;
  cursor: pointer;
  transition: color .2s ease, border-color .2s ease;
}

.lang-btn:hover { color: var(--ink); }

.lang-btn.is-active {
  color: var(--ink);
  border-bottom-color: var(--red);
}

.lang-slash {
  color: var(--line-soft);
  font-weight: 400;
}

/* ---------- 首屏 ---------- */

.hero { padding: clamp(72px, 11vh, 120px) 0 clamp(56px, 8vh, 88px); }

.hero-tag {
  margin: 0 0 clamp(28px, 5vh, 48px);
  font-size: 12px;
  font-weight: 600;
  letter-spacing: .1em;
  color: var(--ink-2);
}

.hero-grid {
  display: grid;
  grid-template-columns: repeat(12, 1fr);
  gap: 28px;
  align-items: end;
}

.hero-title {
  grid-column: 1 / 9;
  margin: 0;
  font-size: clamp(2.5rem, 7vw, 5.5rem);
  font-weight: 700;
  line-height: 1.16;
  letter-spacing: -.01em;
}

.hero-title .line { display: block; }

.hero-lead {
  grid-column: 9 / 13;
  margin: 0;
  font-size: 15px;
  line-height: 1.85;
  color: var(--ink-2);
}

.hero-meta {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 16px;
  margin-top: clamp(40px, 7vh, 72px);
  font-size: 12px;
  font-weight: 600;
  letter-spacing: .06em;
}

.hero-meta-right a {
  color: var(--ink-2);
  transition: color .2s ease;
}

.hero-meta-right a:hover { color: var(--red); }

/* 英文行更短，字号与字距单独校准 */
html[data-lang="en"] .hero-title {
  font-size: clamp(2.75rem, 7.4vw, 6rem);
  line-height: 1.02;
  letter-spacing: -.035em;
}

html[data-lang="en"] .hero-tag,
html[data-lang="en"] .hero-meta { letter-spacing: .12em; text-transform: uppercase; }

/* ---------- 区块骨架 ---------- */

.section {
  padding: clamp(64px, 9vh, 104px) 0;
  border-top: 1px solid var(--line);
}

.split {
  display: grid;
  grid-template-columns: 200px 1fr;
  gap: 56px;
  align-items: start;
}

.label {
  position: relative;
  margin: 0;
  padding-left: 20px;
  font-size: 13px;
  font-weight: 700;
  letter-spacing: .12em;
  text-transform: uppercase;
}

.label::before {
  content: "";
  position: absolute;
  left: 0;
  top: .45em;
  width: 9px;
  height: 9px;
  background: var(--red);
}

.split-body {
  border-left: 1px solid var(--line-soft);
  padding-left: 44px;
}

/* ---------- 业务列表 ---------- */

.services {
  list-style: none;
  margin: 0;
  padding: 0 0 0 44px;
}

.service {
  display: grid;
  grid-template-columns: 52px minmax(160px, 1fr) 1.5fr;
  gap: 32px;
  align-items: start;
  padding: 26px 0 30px;
}

.service + .service { border-top: 1px solid var(--line-soft); }

.num {
  font-size: 13px;
  font-weight: 700;
  letter-spacing: .04em;
  color: var(--red);
  padding-top: 5px;
}

.svc-name {
  margin: 0;
  font-size: 1.25rem;
  font-weight: 700;
  line-height: 1.5;
  letter-spacing: -.01em;
}

.svc-desc {
  margin: 0;
  padding-left: 32px;
  border-left: 1px solid var(--line-soft);
  font-size: 15px;
  line-height: 1.85;
  color: var(--ink-2);
}

/* ---------- 公司 / 联系 ---------- */

.lead-p {
  margin: 0 0 18px;
  max-width: 42em;
  font-size: 16px;
  line-height: 1.9;
  color: var(--ink-2);
}

.lead-p:first-child { color: var(--ink); }

.facts {
  margin: 44px 0 0;
  border-top: 1px solid var(--line);
}

.fact {
  display: grid;
  grid-template-columns: 190px 1fr;
  gap: 32px;
  padding: 16px 0;
  border-bottom: 1px solid var(--line-soft);
}

.fact dt {
  font-size: 11px;
  font-weight: 700;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: var(--ink-3);
  padding-top: 5px;
}

.fact dd {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
}

.contact-block {
  padding: 22px 0;
  border-top: 1px solid var(--line-soft);
}

.contact-block:first-of-type { margin-top: 36px; }

.contact-label {
  display: block;
  margin-bottom: 8px;
  font-size: 11px;
  font-weight: 700;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: var(--ink-3);
}

.contact-mail {
  display: inline-block;
  font-size: clamp(1.25rem, 2.6vw, 1.875rem);
  font-weight: 700;
  letter-spacing: -.01em;
  padding-bottom: 4px;
  border-bottom: 2px solid var(--ink);
  word-break: break-all;
  transition: color .2s ease, border-color .2s ease;
}

.contact-mail:hover {
  color: var(--red);
  border-color: var(--red);
}

/* ---------- 页脚 ---------- */

.site-foot {
  background: var(--ink);
  color: #fff;
  padding: 56px 0 32px;
}

.foot-top {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 24px;
  padding-bottom: 32px;
  border-bottom: 1px solid rgba(255, 255, 255, .16);
}

.foot-cn {
  display: block;
  font-size: 2.25rem;
  font-weight: 700;
  line-height: 1;
  letter-spacing: -.01em;
}

.foot-en {
  display: block;
  margin-top: 12px;
  font-size: 12px;
  letter-spacing: .06em;
  color: #8f8f8f;
}

.foot-back {
  flex: none;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: .1em;
  color: #8f8f8f;
  transition: color .2s ease;
}

.foot-back:hover { color: #fff; }

.foot-bottom {
  padding-top: 24px;
  font-size: 12px;
  line-height: 1.9;
  color: #8f8f8f;
}

.foot-bottom p { margin: 0 0 8px; max-width: 60em; }

.foot-bottom a {
  color: #cfcfcf;
  border-bottom: 1px solid rgba(255, 255, 255, .28);
  transition: color .2s ease, border-color .2s ease;
}

.foot-bottom a:hover { color: #fff; border-color: #fff; }

.foot-legal .dot { margin: 0 8px; color: rgba(255, 255, 255, .3); }

.foot-legal span + span { margin-left: 6px; }

/* ---------- 首屏入场（仅一次，克制） ---------- */

@media (prefers-reduced-motion: no-preference) {
  .hero-tag,
  .hero-title,
  .hero-lead,
  .hero-meta {
    animation: rise .7s cubic-bezier(.2, .7, .3, 1) both;
  }
  .hero-title { animation-delay: .06s; }
  .hero-lead  { animation-delay: .12s; }
  .hero-meta  { animation-delay: .18s; }
}

@keyframes rise {
  from { opacity: 0; transform: translateY(12px); }
  to   { opacity: 1; transform: none; }
}

/* ---------- 响应式 ---------- */

@media (max-width: 980px) {
  .hero-grid { grid-template-columns: 1fr; gap: 32px; align-items: start; }
  .hero-title, .hero-lead { grid-column: 1 / -1; }
  .hero-lead { max-width: 40em; margin-top: 8px; }

  .split { grid-template-columns: 1fr; gap: 32px; }
  .split-body { border-left: 0; padding-left: 0; }
  .services { padding-left: 0; }
}

@media (max-width: 760px) {
  :root { --pad: 22px; --head-h: 62px; }

  .nav { display: none; }

  .service {
    grid-template-columns: 40px 1fr;
    gap: 6px 16px;
    padding: 22px 0 24px;
  }

  .svc-desc {
    grid-column: 2;
    padding-left: 0;
    border-left: 0;
    margin-top: 6px;
  }

  .fact { grid-template-columns: 1fr; gap: 4px; }
  .fact dt { padding-top: 0; }

  .foot-top { flex-direction: column; gap: 20px; }
  .foot-cn { font-size: 1.75rem; }
  .brand-en { display: none; }

  html[data-lang="en"] .hero-title { font-size: clamp(2.5rem, 11vw, 3.5rem); }
}