/* Shared BitTalking design tokens and site chrome. */
:root {
  color-scheme: light;
  --canvas: #f7f8fc;
  --surface: #ffffff;
  --inset: #eff2f8;
  --text: #18223b;
  --muted: #5d6880;
  --text-muted: var(--muted);
  --border: #e3e8f1;
  --line: var(--border);
  --accent: #4263eb;
  --accent-strong: #304ed0;
  --accent-soft: #edf1ff;
  --font:
    -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --font-display: 'Avenir Next', var(--font);
  --shadow: 0 16px 48px -24px rgba(30, 53, 110, 0.2);
  --nav-height: 80px;
}
*,
*::before,
*::after {
  box-sizing: border-box;
}
html {
  scroll-behavior: smooth;
  scroll-padding-top: 104px;
}
body {
  margin: 0;
  color: var(--text);
  background: var(--canvas);
  font-family: var(--font);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}
h1,
h2,
h3,
h4,
p,
figure {
  margin: 0;
}
a {
  color: inherit;
  text-decoration: none;
}
button,
input,
textarea {
  font: inherit;
}
button,
a {
  -webkit-tap-highlight-color: transparent;
}
button {
  cursor: pointer;
}
img {
  display: block;
  max-width: 100%;
}
[hidden] {
  display: none !important;
}
:focus-visible {
  outline: 3px solid var(--accent);
  outline-offset: 4px;
}
::selection {
  background: #dbe3ff;
  color: #1f3597;
}
.container,
.navbar-inner {
  width: min(1200px, calc(100% - 80px));
  margin-inline: auto;
}
.navbar {
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--nav-height);
  background: rgba(255, 255, 255, 0.92);
  border-bottom: 1px solid var(--border);
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
}
.nav-inner,
.navbar-inner {
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}
.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  flex-shrink: 0;
  font-family: var(--font-display);
  font-size: 21px;
  font-weight: 750;
  letter-spacing: -0.7px;
}
.brand img {
  width: 34px;
  height: 34px;
  border-radius: 10px;
}
.brand-name {
  display: flex;
  align-items: center;
  gap: 14px;
}
.brand-primary {
  font-size: 21px;
}
.brand-sub {
  border-left: 1px solid var(--border);
  padding-left: 14px;
  color: var(--muted);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0;
}
.navbar nav {
  display: flex;
  align-items: center;
  gap: 26px;
}
.navbar nav a,
.nav-text-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 7px;
  min-height: 44px;
  color: var(--muted);
  font-size: 13px;
  font-weight: 550;
  white-space: nowrap;
}
.navbar nav a:hover,
.navbar nav .active,
.nav-text-btn:hover {
  color: var(--accent);
}
.navbar nav .active {
  position: relative;
}
.navbar nav .active::after {
  content: '';
  position: absolute;
  width: 18px;
  height: 3px;
  bottom: 0;
  left: calc(50% - 9px);
  background: var(--accent);
  border-radius: 4px;
}
.navbar nav .nav-download {
  background: var(--text);
  color: white;
  padding-inline: 19px;
  border-radius: 12px;
}
.navbar nav .nav-download:hover {
  background: var(--accent-strong);
}
.nav-text-btn {
  padding: 0 14px;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: white;
}
.icon {
  width: 24px;
  height: 24px;
  fill: currentColor;
  flex-shrink: 0;
  vertical-align: middle;
}
.navbar .icon {
  width: 16px;
  height: 16px;
}
.icon-definitions {
  position: absolute;
  width: 0;
  height: 0;
  overflow: hidden;
}
.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}
.skip-link {
  position: fixed;
  top: -80px;
  left: 20px;
  z-index: 110;
  padding: 12px 20px;
  background: white;
  border-radius: 10px;
}
.skip-link:focus {
  top: 12px;
}
.eyebrow,
.section-kicker {
  display: block;
  color: var(--accent);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.12em;
  margin-bottom: 14px;
}
.button,
.btn-submit {
  display: inline-flex;
  justify-content: center;
  align-items: center;
  gap: 12px;
  min-height: 50px;
  padding: 13px 23px;
  border: 1px solid transparent;
  border-radius: 12px;
  font-size: 14px;
  font-weight: 600;
  transition:
    background 0.18s,
    box-shadow 0.18s,
    transform 0.18s;
}
.primary,
.btn-submit {
  color: white;
  background: var(--accent);
  box-shadow: 0 5px 12px -6px #4263eb80;
}
.primary:hover,
.btn-submit:hover:not(:disabled) {
  background: var(--accent-strong);
  transform: translateY(-1px);
}
.secondary {
  color: var(--accent-strong);
  background: var(--accent-soft);
}
.secondary:hover {
  background: #e0e7ff;
}
.button .icon {
  width: 18px;
  height: 18px;
}
.text-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  min-height: 44px;
  color: var(--accent-strong);
  font-size: 13px;
  font-weight: 550;
}
.text-link .icon {
  width: 17px;
  height: 17px;
}
.text-link:hover {
  color: var(--accent);
}
.site-footer {
  border-top: 1px solid var(--border);
  background: white;
}
.site-footer .footer-inner {
  display: flex;
  align-items: center;
  gap: 28px;
  padding-block: 30px;
}
.site-footer .brand {
  font-size: 17px;
}
.site-footer .brand img {
  width: 28px;
  height: 28px;
}
.footer-legal {
  display: grid;
  gap: 3px;
}
.footer-legal p,
.footer-legal a {
  color: var(--muted);
  font-size: 11px;
}
.footer-feedback {
  margin-left: auto;
  font-size: 12px;
  display: flex;
  align-items: center;
  gap: 8px;
}
.footer-feedback:hover,
.footer-legal a:hover {
  color: var(--accent);
}
.footer-feedback .icon {
  width: 16px;
  height: 16px;
}
@media (max-width: 900px) {
  .brand-sub {
    display: none;
  }
  .navbar nav {
    gap: 18px;
  }
}
@media (max-width: 640px) {
  :root {
    --nav-height: 68px;
  }
  .container,
  .navbar-inner {
    width: calc(100% - 40px);
  }
  .navbar nav {
    gap: 12px;
  }
  .navbar nav a,
  .nav-text-btn {
    font-size: 12px;
  }
  .brand,
  .brand-primary {
    font-size: 18px;
  }
  .brand img {
    width: 30px;
    height: 30px;
  }
  .nav-inner,
  .navbar-inner {
    gap: 12px;
  }
  .navbar nav .nav-download {
    padding-inline: 12px;
  }
  .site-footer .footer-inner {
    flex-wrap: wrap;
    gap: 18px;
  }
  .footer-legal {
    order: 3;
    width: 100%;
  }
}
@media (max-width: 370px) {
  .container,
  .navbar-inner {
    width: calc(100% - 28px);
  }
  .navbar nav {
    gap: 8px;
  }
  .brand {
    gap: 6px;
  }
  .brand,
  .brand-primary {
    font-size: 16px;
  }
}
@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  *,
  *::before,
  *::after {
    animation: none !important;
    transition: none !important;
  }
}