/* ============================================================
   1start.net — 长春逸启科技 / Changchun Yiqi Technology
   Shared stylesheet. Modular grid-based identity.
   ============================================================ */

@import url('https://fonts.googleapis.com/css2?family=Space+Grotesk:wght@400;500;600;700&family=Space+Mono:wght@400;700&family=Noto+Sans+SC:wght@400;500;700&display=swap');

:root {
  --ink:        #141414;
  --ink-2:      #2a2a2a;
  --red:        #e0242c;
  --red-press:  #c01d24;
  --paper:      #f4f3f1;
  --paper-2:    #ecebe8;
  --white:      #ffffff;
  --muted:      #6b6b6b;
  --muted-2:    #9a9a9a;
  --line:       #e3e1dd;
  --line-2:     #d4d2cd;

  --display: "Space Grotesk", "Noto Sans SC", "Helvetica Neue", Helvetica, Arial, sans-serif;
  --body:    "Helvetica Neue", Helvetica, "Noto Sans SC", Arial, sans-serif;
  --mono:    "Space Mono", "SFMono-Regular", Menlo, monospace;
  --cjk:     "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;

  --maxw: 1240px;
  --gut: 40px;
  --radius: 4px;

  --ease: cubic-bezier(.22,.61,.36,1);
  --nav-ease: cubic-bezier(.7,0,.2,1);   /* bracket glide easing (from design demo) */
  --nav-ind-dur: 420ms;
}

/* When 中文 is active, bump CJK rendering for display text */
body.lang-zh { --display: "Noto Sans SC", "Space Grotesk", sans-serif; }

* { box-sizing: border-box; }
html { -webkit-font-smoothing: antialiased; text-rendering: optimizeLegibility; scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--body);
  color: var(--ink);
  background: var(--paper);
  font-size: 17px;
  line-height: 1.6;
  letter-spacing: -0.005em;
}
img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
h1,h2,h3,h4 { font-family: var(--display); font-weight: 600; margin: 0; letter-spacing: -0.02em; line-height: 1.04; }

/* ---- bilingual visibility ---- */
.l-en, .l-zh { display: none; }
body.lang-en .l-en { display: block; }
body.lang-zh .l-zh { display: block; }
body.lang-en span.l-en, body.lang-en .l-inline.l-en { display: inline; }
body.lang-zh span.l-zh, body.lang-zh .l-inline.l-zh { display: inline; }

/* rich bilingual blocks (headlines etc.) */
.t-en, .t-zh { display: none; }
body.lang-en .t-en { display: revert; }
body.lang-zh .t-zh { display: revert; }

/* ============================================================
   Layout helpers
   ============================================================ */
.wrap { max-width: var(--maxw); margin: 0 auto; padding: 0 var(--gut); }
.section { padding: 120px 0; }
.section.tight { padding: 84px 0; }
.dark { background: var(--ink); color: var(--white); }
.dark h1,.dark h2,.dark h3 { color: var(--white); }
.paper-2 { background: var(--paper-2); }
.hr { height: 1px; background: var(--line); border: 0; margin: 0; }

.eyebrow {
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--muted);
  display: inline-flex;
  align-items: center;
  gap: 10px;
}
.eyebrow .num { color: var(--red); }
.dark .eyebrow { color: var(--muted-2); }

.lead { font-size: clamp(19px, 2vw, 22px); line-height: 1.5; color: var(--ink-2); max-width: 56ch; }
.dark .lead { color: #cfcfcf; }
.muted { color: var(--muted); }

/* ============================================================
   Logo (modular block mark + wordmark)
   ============================================================ */
.brand { display: inline-flex; align-items: center; gap: 12px; }
.brand .mark { width: 26px; height: auto; display: block; flex: 0 0 auto; }
.wordmark {
  font-family: var(--display);
  font-weight: 700;
  font-size: 22px;
  letter-spacing: -0.03em;
  color: var(--ink);
  line-height: 1;
  white-space: nowrap;
}
.wordmark .dot { color: var(--red); }
.dark .wordmark { color: var(--white); }
.brand .cjk-tag {
  font-family: var(--cjk);
  font-size: 11px;
  letter-spacing: 0.36em;
  color: var(--muted);
  margin-left: 2px;
  display: block;
}

/* ============================================================
   Header
   ============================================================ */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: color-mix(in srgb, var(--paper) 86%, transparent);
  backdrop-filter: saturate(140%) blur(14px);
  border-bottom: 1px solid var(--line);
}
.site-header .bar {
  height: 72px; display: flex; align-items: center; justify-content: space-between;
  max-width: var(--maxw); margin: 0 auto; padding: 0 var(--gut);
}
/* Bracket nav — mono labels + a gliding red [ ] indicator (括号方案) */
.nav { position: relative; display: flex; align-items: center; gap: 2px; }
.nav a.navlink {
  position: relative; z-index: 2; white-space: nowrap; line-height: 1;
  font-family: var(--mono); font-size: 13px; letter-spacing: .08em; text-transform: uppercase;
  color: var(--muted); padding: 9px 17px;
  transition: color var(--nav-ind-dur) var(--nav-ease);
}
body.lang-zh .nav a.navlink { font-family: var(--cjk); letter-spacing: .14em; }
.nav a.navlink:hover { color: var(--ink); }
.nav a.navlink.active { color: var(--ink); font-weight: 700; }

/* the moving indicator — JS sets transform + width to wrap the target item */
.nav-ind {
  position: absolute; top: 50%; left: 0; height: 30px; width: 0;
  transform: translateX(0) translateY(-50%); opacity: 0; pointer-events: none; z-index: 1;
  transition: transform var(--nav-ind-dur) var(--nav-ease),
              width var(--nav-ind-dur) var(--nav-ease),
              opacity .25s var(--nav-ease);
}
.nav-ind.ready { opacity: 1; }
.nav-ind .b { position: absolute; top: 50%; transform: translateY(-50%); color: var(--red);
  font-family: var(--mono); font-weight: 700; font-size: 17px; line-height: 1; }
.nav-ind .b.l { left: 5px; }
.nav-ind .b.r { right: 5px; }

/* Cross-document View Transitions — the bracket glides across full page
   navigations natively, no SPA framework. Progressive enhancement: browsers
   without support just navigate normally. */
@view-transition { navigation: auto; }
.nav-ind { view-transition-name: nav-bracket; }
::view-transition-group(nav-bracket) {
  animation-duration: var(--nav-ind-dur); animation-timing-function: var(--nav-ease);
}
::view-transition-old(root), ::view-transition-new(root) { animation-duration: .26s; }
@media (prefers-reduced-motion: reduce) {
  .nav-ind { transition: none; }
  ::view-transition-group(*), ::view-transition-old(*), ::view-transition-new(*) { animation: none !important; }
}
.header-right { display: flex; align-items: center; gap: 14px; }

.lang-toggle {
  display: inline-flex; align-items: center; border: 1px solid var(--line-2);
  border-radius: 999px; overflow: hidden; font-family: var(--mono); font-size: 12px;
}
.lang-toggle button {
  border: 0; background: transparent; padding: 6px 12px; cursor: pointer;
  color: var(--muted); letter-spacing: 0.05em; font-family: inherit; font-size: inherit;
  transition: background .15s var(--ease), color .15s var(--ease);
}
.lang-toggle button.on { background: var(--ink); color: var(--white); }

/* ============================================================
   Buttons
   ============================================================ */
.btn {
  display: inline-flex; align-items: center; gap: 10px; cursor: pointer;
  font-family: var(--body); font-size: 15px; font-weight: 500; letter-spacing: -0.01em;
  padding: 13px 22px; border-radius: var(--radius); border: 1px solid transparent;
  transition: transform .12s var(--ease), background .15s var(--ease), color .15s var(--ease), border-color .15s var(--ease);
  line-height: 1; white-space: nowrap;
}
.btn:active { transform: translateY(1px); }
.btn .arr { transition: transform .2s var(--ease); }
.btn:hover .arr { transform: translateX(4px); }
.btn-red { background: var(--red); color: var(--white); }
.btn-red:hover { background: var(--red-press); }
.btn-ink { background: var(--ink); color: var(--white); }
.btn-ink:hover { background: #000; }
.btn-ghost { background: transparent; color: var(--ink); border-color: var(--line-2); }
.btn-ghost:hover { border-color: var(--ink); }
.dark .btn-ghost { color: var(--white); border-color: rgba(255,255,255,.28); }
.dark .btn-ghost:hover { border-color: var(--white); }
.btn-sm { padding: 9px 16px; font-size: 14px; }

/* ============================================================
   Modular section header
   ============================================================ */
.sec-head { display: grid; grid-template-columns: 1fr; gap: 22px; margin-bottom: 64px; }
.sec-head h2 { font-size: clamp(30px, 4.2vw, 50px); max-width: 18ch; }
.sec-head .lead { margin-top: 4px; }
@media (min-width: 900px){
  .sec-head.split { grid-template-columns: 1.1fr .9fr; align-items: end; gap: 48px; }
}

/* ============================================================
   Capability / feature cards (modular grid)
   ============================================================ */
.grid { display: grid; gap: 1px; background: var(--line); border: 1px solid var(--line); border-radius: var(--radius); overflow: hidden; }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
@media (max-width: 860px){ .grid-3 { grid-template-columns: 1fr; } .grid-2 { grid-template-columns: 1fr; } }
.cell {
  background: var(--white); padding: 38px 34px 42px; min-height: 240px;
  display: flex; flex-direction: column; transition: background .2s var(--ease);
}
.cell:hover { background: #fbfbfa; }
.cell .idx { font-family: var(--mono); font-size: 12px; color: var(--red); letter-spacing: .14em; }
.cell .glyph { margin: 22px 0 26px; }
.cell h3 { font-size: 22px; margin-bottom: 10px; }
.cell p { color: var(--muted); font-size: 15.5px; line-height: 1.6; margin: 0; }
.cell .grow { flex: 1; }

/* modular block glyph */
.blocks { display: grid; grid-template-columns: repeat(3, 12px); gap: 4px; }
.blocks i { width: 12px; height: 12px; background: var(--ink); display: block; border-radius: 1px; }
.blocks i.r { background: var(--red); }
.blocks i.o { background: transparent; }

/* ============================================================
   Footer
   ============================================================ */
.site-footer { background: var(--ink); color: #bdbdbd; padding: 84px 0 36px; }
.site-footer h4 { color: #fff; font-family: var(--mono); font-size: 12px; letter-spacing: .16em; text-transform: uppercase; font-weight: 400; margin-bottom: 18px; }
.foot-grid { display: grid; grid-template-columns: 1.4fr 1fr 1fr 1fr; gap: 40px; }
@media (max-width: 860px){ .foot-grid { grid-template-columns: 1fr 1fr; gap: 36px 24px; } }
.foot-grid a { color: #bdbdbd; font-size: 14.5px; display: block; padding: 5px 0; transition: color .15s var(--ease); }
.foot-grid a:hover { color: #fff; }
.foot-grid .wordmark { color: #fff; }
.foot-grid .brand .cjk-tag { color: #8a8a8a; }
.foot-about { color: #9a9a9a; font-size: 14px; line-height: 1.65; max-width: 34ch; margin: 18px 0 0; }
.foot-bottom {
  margin-top: 56px; padding-top: 26px; border-top: 1px solid #2c2c2c;
  display: flex; flex-wrap: wrap; gap: 8px 24px; align-items: center; justify-content: space-between;
  font-size: 13px; color: #8a8a8a; font-family: var(--mono); letter-spacing: .02em;
}
.foot-bottom a { color: #8a8a8a; }
.foot-bottom a:hover { color: #cfcfcf; }

/* ============================================================
   Generic page hero (subpages)
   ============================================================ */
.page-hero { padding: 80px 0 64px; border-bottom: 1px solid var(--line); }
.page-hero h1 { font-size: clamp(40px, 6vw, 76px); letter-spacing: -0.035em; }
.page-hero .lead { margin-top: 24px; }

/* ============================================================
   Mobile nav
   ============================================================ */
.menu-btn { display: none; background: transparent; border: 1px solid var(--line-2); border-radius: var(--radius); width: 40px; height: 40px; cursor: pointer; align-items: center; justify-content: center; }
.menu-btn span, .menu-btn span::before, .menu-btn span::after { content:""; display:block; width:16px; height:1.6px; background: var(--ink); position: relative; }
.menu-btn span::before { position:absolute; top:-5px; } .menu-btn span::after { position:absolute; top:5px; }
@media (max-width: 880px){
  .nav { position: fixed; inset: 72px 0 auto 0; flex-direction: column; align-items: stretch; gap: 0;
         background: var(--paper); border-bottom: 1px solid var(--line); padding: 12px var(--gut) 20px; transform: translateY(-130%); transition: transform .3s var(--ease); }
  body.menu-open .nav { transform: translateY(0); }
  .nav a.navlink { padding: 14px 4px; font-size: 17px; letter-spacing: .12em; }
  .nav-ind { display: none; }
  .menu-btn { display: inline-flex; }
  .desktop-cta { display: none; }
}

/* ============================================================
   Subpage components
   ============================================================ */
/* facts / definition list */
.facts { border-top: 1px solid var(--line); }
.facts .fact { display: grid; grid-template-columns: 280px 1fr; gap: 24px; padding: 22px 0; border-bottom: 1px solid var(--line); align-items: baseline; }
@media (max-width: 720px){ .facts .fact { grid-template-columns: 1fr; gap: 6px; } }
.facts .fact dt { font-family: var(--mono); font-size: 12px; letter-spacing: .12em; text-transform: uppercase; color: var(--muted); margin: 0; }
.facts .fact dd { margin: 0; font-size: 16.5px; color: var(--ink); font-weight: 500; }
.facts .fact dd .sub { display: block; font-weight: 400; color: var(--muted); font-size: 14px; margin-top: 3px; }
.badge { display: inline-flex; align-items: center; gap: 7px; font-family: var(--mono); font-size: 12px; letter-spacing: .06em; padding: 4px 10px; border-radius: 999px; background: rgba(224,36,44,.08); color: var(--red); }
.badge .dot { width: 6px; height: 6px; border-radius: 50%; background: var(--red); }
.badge.live { background: rgba(31,138,91,.1); color: #1f8a5b; } .badge.live .dot { background: #1f8a5b; }

/* numbered process steps */
.steps { display: grid; grid-template-columns: repeat(4, 1fr); gap: 1px; background: var(--line); border: 1px solid var(--line); border-radius: var(--radius); overflow: hidden; }
@media (max-width: 880px){ .steps { grid-template-columns: 1fr 1fr; } }
@media (max-width: 520px){ .steps { grid-template-columns: 1fr; } }
.step { background: var(--white); padding: 34px 28px 40px; }
.step .n { font-family: var(--mono); font-size: 13px; color: var(--red); letter-spacing: .1em; }
.step h3 { font-size: 21px; margin: 22px 0 10px; }
.step p { color: var(--muted); font-size: 15px; line-height: 1.6; margin: 0; }
.dark .steps { background: #2a2a2a; border-color: #2a2a2a; }
.dark .step { background: var(--ink); }
.dark .step h3 { color: #fff; }
.dark .step p { color: #a9a9a9; }

/* two-column prose block */
.split-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 56px; align-items: start; }
@media (max-width: 820px){ .split-2 { grid-template-columns: 1fr; gap: 32px; } }
.prose p { font-size: 17px; line-height: 1.7; color: var(--ink-2); margin: 0 0 18px; max-width: 60ch; }
.prose p.muted { color: var(--muted); }

/* contact card */
.contact-card { background: var(--white); border: 1px solid var(--line); border-radius: var(--radius); padding: 40px; }
.contact-card .row { display: grid; grid-template-columns: 120px 1fr; gap: 18px; padding: 16px 0; border-bottom: 1px solid var(--line); }
.contact-card .row:last-child { border-bottom: 0; }
.contact-card .row .k { font-family: var(--mono); font-size: 12px; letter-spacing: .1em; text-transform: uppercase; color: var(--muted); }
.contact-card .row .v { font-size: 16px; }
.contact-card .row .v a { color: var(--red); }

/* Utility */
.stack-sm > * + * { margin-top: 14px; }
.flex { display: flex; } .ac { align-items: center; } .gap { gap: 16px; } .wrapf { flex-wrap: wrap; }
.mt-s { margin-top: 22px; } .mt-m { margin-top: 40px; } .mt-l { margin-top: 64px; }