/* 衍言智能科技（杭州）有限公司 — 全站样式表
   品牌色取自 logo 渐变：#1558E8 → #087FF1 → #11BFE8，正文深色 #18283D */

:root {
  --c-deep: #1558E8;
  --c-mid: #087FF1;
  --c-cyan: #11BFE8;
  --ink: #18283D;
  --ink-2: #44566E;
  --muted: #6B7C93;
  --line: #E4EAF3;
  --bg: #FFFFFF;
  --soft: #F4F8FE;

  --grad: linear-gradient(120deg, #1558E8 0%, #087FF1 50%, #11BFE8 100%);
  --grad-soft: linear-gradient(180deg, #F4F8FE 0%, #FFFFFF 100%);

  --r: 14px;
  --r-sm: 10px;
  --maxw: 1120px;

  --shadow: 0 1px 2px rgba(24, 40, 61, .04), 0 8px 24px rgba(24, 40, 61, .06);
  --shadow-lg: 0 2px 6px rgba(24, 40, 61, .05), 0 18px 48px rgba(21, 88, 232, .12);
}

/* ---------- 基础 ---------- */

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

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

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans CJK SC",
    sans-serif;
  font-size: 16px;
  line-height: 1.75;
  color: var(--ink-2);
  background: var(--bg);
}

h1, h2, h3, h4 {
  color: var(--ink);
  line-height: 1.3;
  margin: 0 0 .5em;
  font-weight: 700;
  letter-spacing: -.01em;
}

h1 { font-size: clamp(2rem, 5vw, 3rem); }
h2 { font-size: clamp(1.5rem, 3.4vw, 2.125rem); }
h3 { font-size: 1.1875rem; }

p { margin: 0 0 1em; }
p:last-child { margin-bottom: 0; }

a { color: var(--c-deep); text-decoration: none; }
a:hover { text-decoration: underline; }

ul { padding-left: 1.25em; }

img, svg { max-width: 100%; }

/* 语言切换：只显示当前语言。两种语言都留在 DOM 里，便于 SEO 与无障碍。
   切换按钮必须豁免：它自身带 lang 属性（为了让屏幕阅读器用正确语音读「English」），
   不豁免的话在中文模式下会被这条规则连自己一起隐藏掉。 */
html[data-lang="zh"] [lang="en"]:not(.lang-toggle),
html[data-lang="en"] [lang="zh"]:not(.lang-toggle) { display: none; }

/* ---------- 布局 ---------- */

.wrap {
  width: 100%;
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 20px;
}

.section { padding: 72px 0; }
.section--soft { background: var(--grad-soft); }
.section--tight { padding: 48px 0; }

.section-head { max-width: 720px; margin-bottom: 40px; }
.section-head p { font-size: 1.0625rem; color: var(--muted); }

.eyebrow {
  display: inline-block;
  font-size: .8125rem;
  font-weight: 600;
  letter-spacing: .08em;
  text-transform: uppercase;
  color: var(--c-mid);
  margin-bottom: .75em;
}

/* ---------- 页头 ---------- */

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(255, 255, 255, .92);
  backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--line);
}

.site-header .wrap {
  display: flex;
  align-items: center;
  gap: 16px;
  min-height: 68px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  flex: none;
  color: var(--ink);
  font-weight: 700;
  text-decoration: none;
}
.brand:hover { text-decoration: none; }
.brand svg, .brand img { height: 34px; width: auto; flex: none; }
.brand-name { font-size: .9375rem; line-height: 1.25; }
.brand-name small {
  display: block;
  font-weight: 400;
  font-size: .6875rem;
  color: var(--muted);
  letter-spacing: .02em;
}

.nav { margin-left: auto; display: flex; align-items: center; gap: 4px; }

.nav a {
  padding: 8px 14px;
  border-radius: var(--r-sm);
  font-size: .9375rem;
  color: var(--ink-2);
  white-space: nowrap;
}
.nav a:hover { background: var(--soft); color: var(--c-deep); text-decoration: none; }
.nav a[aria-current="page"] { color: var(--c-deep); font-weight: 600; }

.lang-toggle {
  margin-left: 8px;
  padding: 6px 14px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: #fff;
  color: var(--ink-2);
  font: inherit;
  font-size: .875rem;
  font-weight: 600;
  cursor: pointer;
  white-space: nowrap;
}
.lang-toggle:hover { border-color: var(--c-mid); color: var(--c-deep); }

.nav-burger {
  display: none;
  margin-left: auto;
  width: 42px;
  height: 42px;
  padding: 0;
  border: 1px solid var(--line);
  border-radius: var(--r-sm);
  background: #fff;
  cursor: pointer;
}
.nav-burger span,
.nav-burger span::before,
.nav-burger span::after {
  display: block;
  width: 18px;
  height: 2px;
  margin: 0 auto;
  background: var(--ink);
  border-radius: 2px;
  content: "";
  position: relative;
}
.nav-burger span::before { position: absolute; top: -6px; }
.nav-burger span::after { position: absolute; top: 6px; }

/* ---------- 按钮 ---------- */

.btn {
  display: inline-block;
  padding: 13px 26px;
  border-radius: 999px;
  font-size: .9375rem;
  font-weight: 600;
  line-height: 1.2;
  text-align: center;
  cursor: pointer;
  border: 1px solid transparent;
  transition: transform .15s ease, box-shadow .15s ease;
}
.btn:hover { text-decoration: none; transform: translateY(-1px); }
.btn--primary { background: var(--grad); color: #fff; box-shadow: var(--shadow-lg); }
.btn--ghost { background: #fff; color: var(--c-deep); border-color: var(--line); }
.btn--ghost:hover { border-color: var(--c-mid); }

.btn-row { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 28px; }

/* ---------- 首屏 ---------- */

.hero {
  position: relative;
  overflow: hidden;
  padding: 92px 0 84px;
  background:
    radial-gradient(760px 420px at 12% -8%, rgba(17, 191, 232, .16), transparent 62%),
    radial-gradient(680px 440px at 88% 6%, rgba(21, 88, 232, .14), transparent 60%),
    linear-gradient(180deg, #F7FAFF 0%, #FFFFFF 100%);
}

.hero h1 { max-width: 15em; }
.hero .lede {
  max-width: 40em;
  margin-top: 20px;
  font-size: clamp(1.0625rem, 2vw, 1.1875rem);
  color: var(--ink-2);
}

.hero-badges {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 32px;
  padding: 0;
  list-style: none;
}
.hero-badges li {
  padding: 7px 15px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: rgba(255, 255, 255, .8);
  font-size: .875rem;
  color: var(--ink-2);
}

/* ---------- 卡片网格 ---------- */

.grid {
  display: grid;
  gap: 22px;
  grid-template-columns: repeat(auto-fit, minmax(268px, 1fr));
}

/* 卡片数量固定时用显式列数，避免 4 张卡在 3 列网格里落单成 3+1 */
.grid--3, .grid--4 { grid-template-columns: repeat(4, 1fr); }
.grid--3 { grid-template-columns: repeat(3, 1fr); }
@media (max-width: 1000px) {
  .grid--3, .grid--4 { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 620px) {
  .grid--3, .grid--4 { grid-template-columns: 1fr; }
}

.card {
  padding: 28px 26px;
  border: 1px solid var(--line);
  border-radius: var(--r);
  background: #fff;
  box-shadow: var(--shadow);
}
.card h3 { margin-bottom: .5em; }
.card p { color: var(--muted); font-size: .9375rem; }

.card-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  margin-bottom: 18px;
  border-radius: 12px;
  background: var(--grad);
  color: #fff;
  font-size: 1.0625rem;
  font-weight: 700;
}
.card-icon svg { width: 22px; height: 22px; display: block; }

/* ---------- 数字条 ---------- */

.stats {
  display: grid;
  gap: 22px;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  margin: 0;
  padding: 0;
  list-style: none;
}
.stats li {
  padding: 24px;
  border-radius: var(--r);
  background: #fff;
  border: 1px solid var(--line);
  text-align: center;
}
.stats b {
  display: block;
  font-size: 1.75rem;
  line-height: 1.2;
  background: var(--grad);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.stats span { font-size: .875rem; color: var(--muted); }

/* ---------- 正文内容页 ---------- */

.page-head {
  padding: 64px 0 40px;
  background: var(--grad-soft);
  border-bottom: 1px solid var(--line);
}
.page-head h1 { margin-bottom: .25em; }
.page-head p { max-width: 46em; color: var(--muted); font-size: 1.0625rem; }

.prose { max-width: 780px; }
.prose h2 { margin-top: 2em; }
.prose h2:first-child { margin-top: 0; }
.prose h3 { margin-top: 1.75em; }
.prose li { margin-bottom: .5em; }

.note {
  padding: 18px 22px;
  border-left: 3px solid var(--c-mid);
  border-radius: 0 var(--r-sm) var(--r-sm) 0;
  background: var(--soft);
  font-size: .9375rem;
}
.note p { color: var(--ink-2); }

/* ---------- 联系方式表 ---------- */

.contact-list {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 18px;
}
.contact-list li {
  padding: 20px 22px;
  border: 1px solid var(--line);
  border-radius: var(--r);
  background: #fff;
}
.contact-list dt,
.contact-list .lbl {
  font-size: .8125rem;
  font-weight: 600;
  letter-spacing: .06em;
  text-transform: uppercase;
  color: var(--c-mid);
  margin-bottom: 6px;
}
.contact-list .val { color: var(--ink); font-size: 1.0625rem; }

/* ---------- FAQ ---------- */

.faq { border-top: 1px solid var(--line); }
.faq details { border-bottom: 1px solid var(--line); }
.faq summary {
  padding: 20px 0;
  cursor: pointer;
  font-weight: 600;
  color: var(--ink);
  list-style: none;
}
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after {
  content: "+";
  float: right;
  font-weight: 400;
  font-size: 1.25rem;
  line-height: 1;
  color: var(--c-mid);
}
.faq details[open] summary::after { content: "\2013"; }
.faq .faq-body { padding-bottom: 20px; color: var(--muted); }

/* ---------- CTA ---------- */

.cta-band {
  padding: 64px 0;
  background: var(--grad);
  color: #fff;
  text-align: center;
}
.cta-band h2 { color: #fff; }
.cta-band p { color: rgba(255, 255, 255, .9); max-width: 40em; margin: 0 auto; }
.cta-band .btn--ghost { background: #fff; border-color: #fff; }
.cta-band .btn-row { justify-content: center; }

/* ---------- 页脚 ---------- */

.site-footer {
  padding: 56px 0 28px;
  background: var(--ink);
  color: rgba(255, 255, 255, .72);
  font-size: .9375rem;
}
.site-footer a { color: rgba(255, 255, 255, .88); }
.site-footer a:hover { color: #fff; }

.footer-grid {
  display: grid;
  gap: 36px;
  grid-template-columns: 1.6fr 1fr 1.4fr;
  margin-bottom: 40px;
}
.footer-brand { display: flex; align-items: flex-start; gap: 12px; }
.footer-brand svg, .footer-brand img { height: 40px; width: auto; flex: none; }
.footer-brand strong { display: block; color: #fff; font-size: .9375rem; line-height: 1.4; }
.footer-brand small { color: rgba(255, 255, 255, .6); font-size: .8125rem; line-height: 1.5; }

.site-footer h4 {
  color: #fff;
  font-size: .8125rem;
  letter-spacing: .08em;
  text-transform: uppercase;
  margin: 0 0 14px;
}
.site-footer ul { margin: 0; padding: 0; list-style: none; }
.site-footer li { margin-bottom: 9px; }
.footer-contact li { color: rgba(255, 255, 255, .72); }

.footer-bottom {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 20px;
  align-items: center;
  padding-top: 24px;
  border-top: 1px solid rgba(255, 255, 255, .14);
  font-size: .8125rem;
  color: rgba(255, 255, 255, .55);
}
.footer-bottom .spacer { margin-left: auto; }

/* ---------- 响应式 ---------- */

@media (max-width: 900px) {
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .footer-grid > :first-child { grid-column: 1 / -1; }
}

@media (max-width: 768px) {
  .section { padding: 56px 0; }
  .hero { padding: 64px 0 56px; }

  .nav-burger { display: block; }

  .nav {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 2px;
    margin: 0;
    padding: 12px 20px 20px;
    background: #fff;
    border-bottom: 1px solid var(--line);
    box-shadow: var(--shadow);
  }
  .nav.is-open { display: flex; }
  .nav a { padding: 12px 14px; }
  .lang-toggle { margin: 8px 0 0; align-self: flex-start; }

  .site-header .wrap { position: relative; }
}

@media (max-width: 560px) {
  .footer-grid { grid-template-columns: 1fr; }
  .brand-name { font-size: .875rem; }
}

/* 打印与无障碍 */

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

@media (prefers-reduced-motion: reduce) {
  * { animation: none !important; transition: none !important; }
  html { scroll-behavior: auto; }
}