/* TeleSilLink — design tokens (verified via ui-ux-pro-max: trust blue + orange CTA) */
:root {
  --color-primary: #2563EB;
  --color-primary-600: #1D4ED8;
  --color-secondary: #3B82F6;
  --color-accent: #EA580C;
  --color-bg: #F8FAFC;
  --color-fg: #1E293B;
  --color-card: #FFFFFF;
  --color-muted: #E9EFF8;
  --color-muted-fg: #475569;
  --color-border: #E2E8F0;
  --color-ring: #2563EB;
  --color-dark: #0B1220;
  --color-dark-2: #0F172A;
  --on-primary: #FFFFFF;
  --on-accent: #FFFFFF;
  --radius: 16px;
  --radius-sm: 10px;
  --shadow-sm: 0 1px 2px rgba(15, 23, 42, .06), 0 1px 3px rgba(15, 23, 42, .08);
  --shadow-md: 0 10px 30px -12px rgba(15, 23, 42, .18);
  --shadow-lg: 0 24px 60px -20px rgba(15, 23, 42, .28);
  --container: 1160px;
  --font: 'Plus Jakarta Sans', 'Noto Sans SC', system-ui, -apple-system, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, 'PingFang SC', 'Microsoft YaHei', sans-serif;
}

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

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.65;
  color: var(--color-fg);
  background: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

/* Language visibility */
[data-lang] { display: none; }
html[data-current-lang="en"] [data-lang="en"] { display: inline; }
html[data-current-lang="zh"] [data-lang="zh"] { display: inline; }

h1, h2, h3 { line-height: 1.2; margin: 0 0 .5em; letter-spacing: -.02em; }
p { margin: 0 0 1em; }
a { color: var(--color-primary); text-decoration: none; }
a:hover { color: var(--color-primary-600); }
img, svg { max-width: 100%; }
button { font-family: inherit; }

.container { width: 100%; max-width: var(--container); margin: 0 auto; padding: 0 24px; }
.container-narrow { max-width: 820px; }

.skip-link {
  position: absolute; left: -9999px; top: 0; z-index: 100;
  background: var(--color-primary); color: #fff; padding: 10px 16px; border-radius: 0 0 8px 0;
}
.skip-link:focus { left: 0; }

:focus-visible { outline: 3px solid var(--color-ring); outline-offset: 2px; border-radius: 6px; }

/* Header */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: rgba(248, 250, 252, .82);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid transparent;
  transition: border-color .25s ease, box-shadow .25s ease, background .25s ease;
}
.site-header.is-scrolled { border-bottom-color: var(--color-border); box-shadow: var(--shadow-sm); }
.header-inner { display: flex; align-items: center; gap: 20px; min-height: 68px; }

.brand { display: inline-flex; align-items: center; gap: 10px; color: var(--color-fg); font-weight: 800; font-size: 1.15rem; letter-spacing: -.01em; }
.brand:hover { color: var(--color-fg); }
.brand-mark { display: inline-flex; }
.brand-name { white-space: nowrap; }

.main-nav { display: flex; align-items: center; gap: 4px; margin-left: auto; }
.main-nav a { color: var(--color-muted-fg); font-weight: 500; font-size: .95rem; padding: 9px 12px; border-radius: 8px; transition: color .2s ease, background .2s ease; }
.main-nav a:hover { color: var(--color-primary); background: var(--color-muted); }

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

.lang-switch { display: inline-flex; background: var(--color-muted); border: 1px solid var(--color-border); border-radius: 999px; padding: 3px; }
.lang-switch button, .footer-lang button {
  border: 0; background: transparent; cursor: pointer; font-size: .82rem; font-weight: 600; color: var(--color-muted-fg);
  padding: 5px 12px; border-radius: 999px; transition: background .2s ease, color .2s ease;
}
.lang-switch button.is-active { background: var(--color-card); color: var(--color-primary); box-shadow: var(--shadow-sm); }

.nav-toggle { display: none; flex-direction: column; gap: 4px; background: transparent; border: 0; padding: 8px; cursor: pointer; }
.nav-toggle span { width: 22px; height: 2px; background: var(--color-fg); border-radius: 2px; transition: transform .25s ease, opacity .25s ease; }
.nav-toggle[aria-expanded="true"] span:nth-child(1) { transform: translateY(6px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] span:nth-child(3) { transform: translateY(-6px) rotate(-45deg); }

/* Buttons */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  font-weight: 600; font-size: .95rem; line-height: 1; padding: 13px 22px; min-height: 46px;
  border-radius: 999px; border: 1px solid transparent; cursor: pointer;
  transition: transform .18s ease, background .2s ease, box-shadow .2s ease, border-color .2s ease, color .2s ease;
}
.btn-sm { padding: 10px 16px; min-height: 40px; font-size: .9rem; }
.btn-primary { background: var(--color-primary); color: var(--on-primary); box-shadow: 0 10px 24px -12px rgba(37, 99, 235, .8); }
.btn-primary:hover { background: var(--color-primary-600); color: #fff; transform: translateY(-2px); box-shadow: 0 16px 30px -14px rgba(37, 99, 235, .9); }
.btn-ghost { background: transparent; color: var(--color-fg); border-color: var(--color-border); }
.btn-ghost:hover { border-color: var(--color-primary); color: var(--color-primary); background: var(--color-muted); transform: translateY(-2px); }
.btn:active { transform: translateY(0); }

/* Hero */
.hero { position: relative; overflow: hidden; padding: 84px 0 72px; }
.hero-glow {
  position: absolute; inset: -20% -10% auto -10%; height: 520px; z-index: 0; pointer-events: none;
  background:
    radial-gradient(38% 55% at 18% 22%, rgba(37, 99, 235, .22), transparent 70%),
    radial-gradient(34% 50% at 82% 8%, rgba(234, 88, 12, .16), transparent 72%),
    radial-gradient(30% 45% at 62% 60%, rgba(59, 130, 246, .18), transparent 70%);
  filter: blur(6px);
}
.hero-inner { position: relative; z-index: 1; display: grid; grid-template-columns: 1.1fr .9fr; gap: 56px; align-items: center; }
.eyebrow {
  display: inline-block; font-size: .8rem; font-weight: 700; letter-spacing: .08em; text-transform: uppercase;
  color: var(--color-primary); background: var(--color-muted); border: 1px solid var(--color-border);
  padding: 6px 14px; border-radius: 999px; margin: 0 0 18px;
}
.hero h1 { font-size: clamp(2rem, 4.4vw, 3.35rem); font-weight: 800; margin-bottom: .5em; }
.lead { font-size: clamp(1.02rem, 1.6vw, 1.18rem); color: var(--color-muted-fg); max-width: 40ch; }
.hero-cta { display: flex; flex-wrap: wrap; gap: 12px; margin: 26px 0 22px; }
.hero-chips { display: flex; flex-wrap: wrap; gap: 8px; list-style: none; margin: 0; padding: 0; }
.hero-chips li {
  font-size: .8rem; font-weight: 600; color: var(--color-muted-fg);
  background: var(--color-card); border: 1px solid var(--color-border); border-radius: 999px; padding: 6px 12px;
}

.hero-panel { display: grid; gap: 12px; }
.glass-card {
  background: rgba(255, 255, 255, .62);
  border: 1px solid rgba(255, 255, 255, .75);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-radius: var(--radius);
  box-shadow: var(--shadow-md);
  padding: 16px 18px;
}
.panel-head { display: flex; align-items: center; gap: 7px; padding: 12px 16px; }
.panel-head .dot { width: 10px; height: 10px; border-radius: 50%; background: #CBD5E1; }
.panel-head .dot:first-child { background: #F87171; }
.panel-head .dot:nth-child(2) { background: #FBBF24; }
.panel-head .dot:nth-child(3) { background: #34D399; }
.panel-title { margin-left: 8px; font-size: .82rem; font-weight: 600; color: var(--color-muted-fg); font-family: ui-monospace, SFMono-Regular, Menlo, monospace; }
.panel-row { display: flex; justify-content: space-between; align-items: center; gap: 12px; }
.panel-row .k { font-family: ui-monospace, SFMono-Regular, Menlo, monospace; font-weight: 700; color: var(--color-primary); font-size: .85rem; }
.panel-row .v { font-size: .84rem; color: var(--color-muted-fg); }
.panel-row.muted { background: rgba(255, 255, 255, .45); }

/* Sections */
.section { padding: 84px 0; }
.section-tint { background: linear-gradient(180deg, #fff 0%, var(--color-bg) 100%); }
.section-head { max-width: 720px; margin: 0 auto 48px; text-align: center; }
.section-title { font-size: clamp(1.6rem, 3vw, 2.35rem); font-weight: 800; }
.section-sub { color: var(--color-muted-fg); font-size: 1.05rem; margin: 0; }

.grid { display: grid; gap: 22px; }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-2 { grid-template-columns: repeat(2, 1fr); }

.card {
  background: var(--color-card); border: 1px solid var(--color-border); border-radius: var(--radius);
  padding: 28px; box-shadow: var(--shadow-sm);
  transition: transform .25s ease, box-shadow .25s ease, border-color .25s ease;
}
.card:hover { transform: translateY(-4px); box-shadow: var(--shadow-md); border-color: #CBD5E1; }
.card h3 { font-size: 1.18rem; font-weight: 700; margin-bottom: .4em; }
.card p { margin: 0; color: var(--color-muted-fg); }
.icon {
  display: inline-flex; align-items: center; justify-content: center; width: 48px; height: 48px; margin-bottom: 16px;
  border-radius: 12px; color: var(--color-primary); background: var(--color-muted); border: 1px solid var(--color-border);
}
.card-service { border-top: 3px solid var(--color-primary); }

/* Dark section */
.section-dark { background: var(--color-dark); color: #E2E8F0; }
.section-dark .section-title { color: #fff; }
.split { display: grid; grid-template-columns: 1fr 1fr; gap: 56px; align-items: center; }
.split-copy p { color: #94A3B8; font-size: 1.05rem; }
.feature-list { list-style: none; margin: 24px 0 0; padding: 0; display: grid; gap: 14px; }
.feature-list li { color: #CBD5E1; padding-left: 30px; position: relative; }
.feature-list li::before {
  content: ""; position: absolute; left: 0; top: 8px; width: 16px; height: 16px; border-radius: 50%;
  background: rgba(37, 99, 235, .25); border: 1px solid var(--color-secondary);
}
.feature-list strong { color: #fff; }

.stack { display: grid; gap: 12px; }
.stack-layer {
  display: flex; flex-wrap: wrap; align-items: baseline; gap: 6px 14px;
  padding: 18px 22px; border-radius: var(--radius-sm);
  background: var(--color-dark-2); border: 1px solid #1E293B;
  transition: transform .25s ease, border-color .25s ease;
}
.stack-layer:hover { transform: translateX(6px); border-color: var(--color-secondary); }
.layer-name { font-weight: 700; color: #fff; }
.layer-desc { font-size: .86rem; color: #94A3B8; font-family: ui-monospace, SFMono-Regular, Menlo, monospace; }
.l1 { border-left: 3px solid #60A5FA; }
.l2 { border-left: 3px solid #38BDF8; }
.l3 { border-left: 3px solid #34D399; }
.l4 { border-left: 3px solid #FBBF24; }

/* Steps */
.steps { list-style: none; margin: 0; padding: 0; display: grid; grid-template-columns: repeat(4, 1fr); gap: 22px; counter-reset: step; }
.steps li {
  background: var(--color-card); border: 1px solid var(--color-border); border-radius: var(--radius);
  padding: 26px; position: relative; box-shadow: var(--shadow-sm);
  transition: transform .25s ease, box-shadow .25s ease;
}
.steps li:hover { transform: translateY(-4px); box-shadow: var(--shadow-md); }
.step-num {
  display: inline-flex; align-items: center; justify-content: center; width: 40px; height: 40px; margin-bottom: 14px;
  border-radius: 12px; background: var(--color-primary); color: #fff; font-weight: 800; font-size: 1.05rem;
}
.steps h3 { font-size: 1.08rem; }
.steps p { margin: 0; color: var(--color-muted-fg); font-size: .95rem; }

/* FAQ */
.faq-list { display: grid; gap: 12px; }
.faq {
  background: var(--color-card); border: 1px solid var(--color-border); border-radius: var(--radius);
  padding: 4px 22px; box-shadow: var(--shadow-sm); transition: border-color .2s ease;
}
.faq[open] { border-color: var(--color-secondary); }
.faq summary {
  cursor: pointer; list-style: none; font-weight: 700; font-size: 1.05rem; padding: 18px 30px 18px 0;
  position: relative; color: var(--color-fg);
}
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after {
  content: ""; position: absolute; right: 4px; top: 24px; width: 9px; height: 9px;
  border-right: 2px solid var(--color-primary); border-bottom: 2px solid var(--color-primary);
  transform: rotate(45deg); transition: transform .25s ease;
}
.faq[open] summary::after { transform: rotate(-135deg); }
.faq p { color: var(--color-muted-fg); padding-bottom: 6px; margin: 0 0 16px; }

/* CTA */
.cta-section { padding-bottom: 96px; }
.cta-card {
  display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 28px;
  background: linear-gradient(120deg, #1D4ED8 0%, #2563EB 55%, #3B82F6 100%);
  color: #fff; border-radius: 24px; padding: 48px; box-shadow: var(--shadow-lg);
}
.cta-card .section-title { color: #fff; margin-bottom: .3em; }
.cta-copy { max-width: 620px; }
.cta-copy p { color: rgba(255, 255, 255, .88); margin: 0; }
.cta-actions { display: flex; flex-wrap: wrap; gap: 12px; }
.cta-card .btn-primary { background: var(--color-accent); color: var(--on-accent); box-shadow: 0 12px 26px -12px rgba(0, 0, 0, .6); }
.cta-card .btn-primary:hover { background: #C2410C; color: #fff; }
.cta-card .btn-ghost { color: #fff; border-color: rgba(255, 255, 255, .55); }
.cta-card .btn-ghost:hover { background: rgba(255, 255, 255, .12); color: #fff; border-color: #fff; }

/* Footer */
.site-footer { background: #0B1220; color: #94A3B8; padding: 54px 0 28px; }
.footer-inner { display: flex; flex-wrap: wrap; gap: 28px; justify-content: space-between; align-items: flex-start; }
.footer-brand { max-width: 360px; }
.footer-brand .brand { color: #fff; margin-bottom: 12px; }
.footer-brand p { font-size: .92rem; margin: 0; }
.footer-nav { display: flex; flex-wrap: wrap; gap: 6px 18px; }
.footer-nav a { color: #CBD5E1; font-size: .92rem; }
.footer-nav a:hover { color: #fff; }
.footer-bottom {
  display: flex; flex-wrap: wrap; gap: 12px; justify-content: space-between; align-items: center;
  margin-top: 34px; padding-top: 20px; border-top: 1px solid #1E293B; font-size: .85rem;
}
.footer-bottom p { margin: 0; }
.footer-lang { display: inline-flex; align-items: center; gap: 8px; }
.footer-lang button { color: #CBD5E1; padding: 4px 6px; }
.footer-lang button:hover { color: #fff; }

/* Reveal animation */
.reveal { opacity: 0; transform: translateY(22px); transition: opacity .6s ease, transform .6s ease; }
.reveal.is-visible { opacity: 1; transform: none; }

/* Responsive */
@media (max-width: 980px) {
  .hero-inner { grid-template-columns: 1fr; gap: 40px; }
  .split { grid-template-columns: 1fr; gap: 36px; }
  .grid-3, .steps { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 820px) {
  .main-nav {
    position: fixed; inset: 68px 0 auto 0; flex-direction: column; align-items: stretch; gap: 2px;
    background: rgba(248, 250, 252, .98); backdrop-filter: blur(14px); -webkit-backdrop-filter: blur(14px);
    padding: 14px 20px 22px; border-bottom: 1px solid var(--color-border); box-shadow: var(--shadow-md);
    transform: translateY(-140%); transition: transform .3s ease; max-height: calc(100vh - 68px); overflow: auto;
  }
  .main-nav.is-open { transform: translateY(0); }
  .main-nav a { padding: 12px; font-size: 1rem; }
  .nav-toggle { display: flex; }
  .header-actions .btn { display: none; }
}
@media (max-width: 640px) {
  .section { padding: 64px 0; }
  .grid-3, .grid-2, .steps { grid-template-columns: 1fr; }
  .cta-card { padding: 34px 26px; }
  .hero { padding: 56px 0 48px; }
  .hero-cta .btn { flex: 1 1 auto; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation-duration: .001ms !important; transition-duration: .001ms !important; }
  .reveal { opacity: 1; transform: none; }
  .card:hover, .steps li:hover, .stack-layer:hover, .btn:hover { transform: none; }
}