/* 言讯 IM 官网样式 */

:root {
  --ink: #14161a;
  --ink-2: #5b6472;
  --ink-3: #8b95a5;
  --line: #e5e8ec;
  --line-2: #f0f2f5;
  --bg: #ffffff;
  --bg-soft: #f7f8fa;
  --brand: #1554d8;
  --brand-dark: #0f42ab;
  --brand-soft: #eef3fd;
  --radius: 6px;
  --wrap: 1120px;
}

* { box-sizing: border-box; }

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

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  font-size: 15px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

a { color: inherit; text-decoration: none; }
img, svg { display: block; max-width: 100%; }

.wrap {
  max-width: var(--wrap);
  margin: 0 auto;
  padding: 0 24px;
}

/* ---------- 顶部导航 ---------- */

.header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: saturate(180%) blur(8px);
  border-bottom: 1px solid transparent;
  transition: border-color .2s ease, box-shadow .2s ease;
}
.header.is-stuck {
  border-bottom-color: var(--line);
  box-shadow: 0 1px 2px rgba(20, 22, 26, .04);
}

.nav {
  height: 64px;
  display: flex;
  align-items: center;
  gap: 32px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 9px;
  font-size: 17px;
  font-weight: 600;
  letter-spacing: .01em;
  white-space: nowrap;
}
.logo-mark {
  width: 22px;
  height: 22px;
  border-radius: 5px;
  background: var(--brand);
  position: relative;
  flex: none;
}
.logo-mark::after {
  content: "";
  position: absolute;
  left: 5px;
  top: 6px;
  width: 12px;
  height: 8px;
  border: 2px solid #fff;
  border-radius: 3px;
  border-bottom-left-radius: 0;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 26px;
  margin-left: auto;
  font-size: 15px;
  color: var(--ink-2);
}
.nav-links a { transition: color .15s ease; }
.nav-links a:hover { color: var(--ink); }
.nav-links a.is-active { color: var(--brand); }

.nav-tel {
  font-size: 14px;
  color: var(--ink-2);
  padding-left: 26px;
  border-left: 1px solid var(--line);
  white-space: nowrap;
}

.nav-toggle {
  display: none;
  margin-left: auto;
  width: 40px;
  height: 40px;
  border: 0;
  background: transparent;
  cursor: pointer;
  padding: 0;
}
.nav-toggle span {
  display: block;
  width: 20px;
  height: 1.5px;
  background: var(--ink);
  margin: 5px auto;
  transition: transform .2s ease, opacity .2s ease;
}

/* ---------- 首屏 ---------- */

.hero {
  padding: 84px 0 72px;
  border-bottom: 1px solid var(--line-2);
}
.hero-inner {
  display: grid;
  grid-template-columns: 1fr 420px;
  gap: 64px;
  align-items: center;
}
.hero h1 {
  margin: 0 0 18px;
  font-size: 40px;
  line-height: 1.3;
  font-weight: 600;
  letter-spacing: -.01em;
}
.hero-sub {
  margin: 0 0 8px;
  font-size: 17px;
  color: var(--ink-2);
  max-width: 30em;
}
.hero-note {
  margin: 0 0 30px;
  font-size: 14px;
  color: var(--ink-3);
}

.btn-row { display: flex; gap: 12px; flex-wrap: wrap; }
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  height: 42px;
  padding: 0 22px;
  border-radius: var(--radius);
  font-size: 15px;
  border: 1px solid transparent;
  transition: background-color .15s ease, border-color .15s ease, color .15s ease;
  white-space: nowrap;
}
.btn-primary { background: var(--brand); color: #fff; }
.btn-primary:hover { background: var(--brand-dark); }
.btn-ghost { border-color: var(--line); color: var(--ink); background: #fff; }
.btn-ghost:hover { border-color: #cdd3db; }

/* 首屏示意窗口 */
.mock {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 8px;
  overflow: hidden;
}
.mock-bar {
  height: 40px;
  border-bottom: 1px solid var(--line-2);
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 0 14px;
  font-size: 13px;
  color: var(--ink);
  background: var(--bg-soft);
}
.mock-dot { width: 9px; height: 9px; border-radius: 50%; background: #d7dbe1; }
.mock-body { padding: 16px 14px; display: grid; gap: 12px; }
.bubble {
  max-width: 78%;
  padding: 9px 12px;
  border-radius: 8px;
  font-size: 14px;
  line-height: 1.6;
}
.bubble-in { background: var(--bg-soft); border: 1px solid var(--line-2); }
.bubble-out {
  background: var(--brand-soft);
  border: 1px solid #dde6fa;
  justify-self: end;
  color: #12386f;
}
.mock-meta {
  font-size: 12px;
  color: var(--ink-3);
  text-align: center;
  margin-top: -2px;
}
.mock-input {
  border-top: 1px solid var(--line-2);
  padding: 12px 14px;
  font-size: 13px;
  color: var(--ink-3);
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.mock-send {
  font-size: 12px;
  color: #fff;
  background: var(--brand);
  padding: 5px 12px;
  border-radius: 4px;
}

/* ---------- 通用区块 ---------- */

.section { padding: 72px 0; }
.section + .section { border-top: 1px solid var(--line-2); }
.section-soft { background: var(--bg-soft); }

.section-head { max-width: 640px; margin-bottom: 40px; }
.section-head h2 {
  margin: 0 0 10px;
  font-size: 26px;
  font-weight: 600;
  letter-spacing: -.01em;
  scroll-margin-top: 90px;
}
.section-head p { margin: 0; color: var(--ink-2); }

/* 能力卡片 */
.grid { display: grid; gap: 1px; background: var(--line); border: 1px solid var(--line); border-radius: 8px; overflow: hidden; }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-5 { grid-template-columns: repeat(5, 1fr); }

.card {
  background: #fff;
  padding: 26px 24px 28px;
  transition: background-color .15s ease;
}
.section-soft .card { background: var(--bg-soft); }
.card:hover { background: var(--bg-soft); }
.section-soft .card:hover { background: #fff; }

.card-icon { color: var(--brand); margin-bottom: 14px; }
.card h3 { margin: 0 0 6px; font-size: 16px; font-weight: 600; }
.card p { margin: 0; font-size: 14px; color: var(--ink-2); }

/* 多端 */
.plat { text-align: left; }
.plat strong { display: block; font-size: 15px; font-weight: 600; margin-bottom: 2px; }
.plat span { font-size: 13px; color: var(--ink-2); }

/* 部署 */
.deploy-list { margin: 14px 0 0; padding: 0; list-style: none; }
.deploy-list li {
  position: relative;
  padding-left: 16px;
  font-size: 14px;
  color: var(--ink-2);
  margin-bottom: 6px;
}
.deploy-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 10px;
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--brand);
}

/* 下载 */
.dl-row { display: flex; flex-wrap: wrap; gap: 12px; }
.dl-item {
  display: flex;
  align-items: center;
  gap: 10px;
  height: 46px;
  padding: 0 20px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  font-size: 15px;
  background: #fff;
  transition: border-color .15s ease, color .15s ease;
}
.dl-item:hover { border-color: var(--brand); color: var(--brand); }
.dl-item svg { flex: none; }
.dl-hint { margin: 18px 0 0; font-size: 13px; color: var(--ink-3); }

/* 联系 */
.contact-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 32px;
  border-top: 1px solid var(--line);
  padding-top: 32px;
}
.contact-item dt { font-size: 13px; color: var(--ink-3); margin-bottom: 4px; }
.contact-item dd { margin: 0; font-size: 15px; }
.contact-item a:hover { color: var(--brand); }

/* ---------- 页脚 ---------- */

.footer {
  border-top: 1px solid var(--line);
  padding: 28px 0 36px;
  font-size: 13px;
  color: var(--ink-3);
}
.footer-inner {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
  align-items: flex-start;
}
.footer-links { display: flex; gap: 18px; flex-wrap: wrap; }
.footer a:hover { color: var(--brand); }

/* ---------- 响应式 ---------- */

@media (max-width: 900px) {
  .hero-inner { grid-template-columns: 1fr; gap: 40px; }
  .hero { padding: 56px 0 52px; }
  .hero h1 { font-size: 32px; }
  .grid-3, .grid-5 { grid-template-columns: repeat(2, 1fr); }
  .contact-grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 640px) {
  .nav-links {
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    display: none;
    flex-direction: column;
    align-items: flex-start;
    gap: 0;
    background: #fff;
    border-bottom: 1px solid var(--line);
    padding: 8px 24px 16px;
    margin: 0;
  }
  .nav-links.is-open { display: flex; }
  .nav-links a { padding: 10px 0; width: 100%; border-bottom: 1px solid var(--line-2); }
  .nav-links .nav-tel { border: 0; padding-left: 0; padding-top: 14px; border-bottom: 0; }
  .nav-toggle { display: block; }
  .grid-2, .grid-3, .grid-5 { grid-template-columns: 1fr; }
  .contact-grid { grid-template-columns: 1fr; gap: 20px; }
  .section { padding: 52px 0; }
  .hero h1 { font-size: 27px; }
  .dl-item { flex: 1 1 100%; }
}