/* ============================================================
   Yusheng Intelligent Technology — shared stylesheet
   Light tech-industrial theme · white + light blue + cyan
   ============================================================ */

:root {
  --bg:         #f4f9fe;
  --bg-deep:    #e9f2fb;
  --panel:      #ffffff;
  --panel-2:    #e4eef9;
  --line:       #d7e5f4;
  --line-2:     #b5cfea;
  --text:       #0d1f33;
  --muted:      #47607d;
  --dim:        #7d93ad;
  --brand:      #2e86ff;
  --brand-deep: #1d6fd6;
  --accent:     #0891b2;
  --cyan:       #2fd6ff;
  --warn:       #ff8a2a;
  --grad:       linear-gradient(135deg, #2e86ff 0%, #2fd6ff 100%);
  --grad-warn:  linear-gradient(135deg, #ff7a1a 0%, #ffb02e 100%);
  --font-display: "Rajdhani", "Segoe UI", sans-serif;
  --font-body:    "Inter", "Segoe UI", "Microsoft YaHei", sans-serif;
  --shadow: 0 18px 48px rgba(46, 84, 130, .16);
  --radius: 14px;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

img { max-width: 100%; display: block; }
a { color: var(--accent); text-decoration: none; transition: color .2s; }
a:hover { color: var(--brand); }
ul { list-style: none; }
::selection { background: rgba(47, 214, 255, .3); }

.container { max-width: 1200px; margin: 0 auto; padding: 0 24px; }

/* ---------- Typography ---------- */
h1, h2, h3, h4 { font-family: var(--font-display); font-weight: 700; line-height: 1.15; letter-spacing: .01em; }
h1 { font-size: clamp(34px, 5.4vw, 60px); text-transform: uppercase; }
h2 { font-size: clamp(26px, 3.4vw, 40px); text-transform: uppercase; }
h3 { font-size: 21px; text-transform: uppercase; }

.grad {
  background: var(--grad);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  color: transparent;
}
.grad-warn {
  background: var(--grad-warn);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  color: transparent;
}
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-size: 13px;
  font-weight: 600;
  letter-spacing: .18em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 16px;
}
.eyebrow::before {
  content: "";
  width: 26px; height: 2px;
  background: var(--grad);
}

.lead { color: var(--muted); font-size: 17px; max-width: 720px; }

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 13px 26px;
  border-radius: 8px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 15px;
  letter-spacing: .06em;
  text-transform: uppercase;
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform .15s, box-shadow .2s, background .2s;
}
.btn:hover { transform: translateY(-2px); }
.btn:active { transform: translateY(0); }
.btn-accent {
  background: var(--grad);
  color: #ffffff;
  box-shadow: 0 10px 26px rgba(46, 134, 255, .28);
}
.btn-accent:hover { box-shadow: 0 16px 36px rgba(46, 134, 255, .4); }
.btn-warn {
  background: var(--grad-warn);
  color: #ffffff;
  box-shadow: 0 10px 26px rgba(255, 138, 42, .3);
}
.btn-ghost {
  background: #ffffff;
  color: var(--text);
  border-color: var(--line-2);
}
.btn-ghost:hover { border-color: var(--brand); color: var(--brand); }
.btn-sm { padding: 9px 18px; font-size: 13px; }

/* ---------- Header ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, .88);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid transparent;
  transition: border-color .2s, box-shadow .2s;
}
.site-header.scrolled { border-bottom-color: var(--line); box-shadow: 0 8px 26px rgba(46, 84, 130, .1); }
.header-inner { display: flex; align-items: center; gap: 24px; height: 72px; }

.brand { display: flex; align-items: center; gap: 12px; color: var(--text); }
.brand:hover { color: var(--text); }
.brand-mark {
  display: grid; place-items: center;
  width: 44px; height: 44px;
  border-radius: 10px;
  background: linear-gradient(135deg, rgba(46, 134, 255, .14), rgba(47, 214, 255, .1));
  border: 1px solid var(--line-2);
}
.brand-text { display: flex; flex-direction: column; line-height: 1.1; }
.brand-text strong { font-family: var(--font-display); font-size: 20px; letter-spacing: .05em; text-transform: uppercase; }
.brand-text small { color: var(--muted); font-size: 11px; letter-spacing: .1em; text-transform: uppercase; }

.nav { display: flex; gap: 4px; margin-left: auto; }
.nav a {
  color: var(--muted);
  font-size: 14px;
  font-weight: 500;
  padding: 9px 13px;
  border-radius: 7px;
  transition: color .2s, background .2s;
}
.nav a:hover { color: var(--text); background: rgba(47, 214, 255, .12); }
.nav a.active { color: var(--accent); background: rgba(47, 214, 255, .16); }

.header-actions { display: flex; align-items: center; gap: 12px; }
.lang-toggle {
  background: #ffffff;
  border: 1px solid var(--line-2);
  color: var(--muted);
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 13px;
  padding: 7px 14px;
  border-radius: 7px;
  cursor: pointer;
  transition: color .2s, border-color .2s;
}
.lang-toggle:hover { color: var(--accent); border-color: var(--accent); }

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: 0;
  cursor: pointer;
  padding: 6px;
}
.nav-toggle span { width: 22px; height: 2px; background: var(--text); border-radius: 2px; transition: transform .25s, opacity .25s; }
.nav-toggle.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle.open span:nth-child(2) { opacity: 0; }
.nav-toggle.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ---------- Hero ---------- */
.hero { position: relative; overflow: hidden; padding: 96px 0 88px; }
.hero::before {
  content: "";
  position: absolute; inset: 0;
  background:
    radial-gradient(900px 480px at 78% -10%, rgba(46, 134, 255, .14), transparent 60%),
    radial-gradient(700px 420px at 8% 110%, rgba(47, 214, 255, .14), transparent 60%);
  pointer-events: none;
}
/* machining blueprint grid */
.hero::after {
  content: "";
  position: absolute; inset: 0;
  background-image:
    linear-gradient(rgba(47, 214, 255, .1) 1px, transparent 1px),
    linear-gradient(90deg, rgba(47, 214, 255, .1) 1px, transparent 1px);
  background-size: 48px 48px;
  mask-image: radial-gradient(1000px 500px at 70% 30%, #000 20%, transparent 75%);
  -webkit-mask-image: radial-gradient(1000px 500px at 70% 30%, #000 20%, transparent 75%);
  pointer-events: none;
}
.hero-inner { position: relative; z-index: 1; display: grid; grid-template-columns: 1.05fr .95fr; gap: 48px; align-items: center; }
.hero-copy h1 { margin-bottom: 20px; }
.hero-copy .lead { margin-bottom: 34px; }
.hero-cta { display: flex; gap: 14px; flex-wrap: wrap; }

.hero-metrics {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
  margin-top: 44px;
}
.metric {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 18px 16px;
  background: rgba(255, 255, 255, .85);
}
.metric b { display: block; font-family: var(--font-display); font-size: 26px; color: var(--brand); line-height: 1.1; }
.metric span { color: var(--muted); font-size: 12.5px; letter-spacing: .04em; }

/* standalone metric row (about page) */
.metric-row { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; }
.muted-note { color: var(--dim); font-size: 12.5px; }

/* hero visual (CSS machine composition, photo added later) */
.hero-visual { position: relative; }
.hero-visual .visual-frame {
  position: relative;
  border: 1px solid var(--line-2);
  border-radius: var(--radius);
  background: linear-gradient(160deg, #ffffff 0%, #e6f1fb 100%);
  overflow: hidden;
  min-height: 360px;
  display: grid;
  place-items: center;
}
.hero-visual .visual-frame::after {
  content: "";
  position: absolute; inset: 0;
  background-image: linear-gradient(rgba(47, 214, 255, .09) 1px, transparent 1px),
                    linear-gradient(90deg, rgba(47, 214, 255, .09) 1px, transparent 1px);
  background-size: 32px 32px;
}
.hero-visual svg { position: relative; z-index: 1; width: 86%; height: auto; }
.hero-visual .img-layer {
  position: absolute; inset: 0; z-index: 2;
  background-size: cover; background-position: center;
  opacity: 0;
  transition: opacity .6s;
}
.hero-visual .img-layer.show { opacity: 1; }

/* ---------- Sections ---------- */
.section { padding: 84px 0; position: relative; }
.section.alt { background: var(--bg-deep); border-block: 1px solid var(--line); }
.sec-head { margin-bottom: 46px; max-width: 820px; }
.sec-head .lead { margin-top: 10px; }
.sec-head.center { margin-inline: auto; text-align: center; }
.sec-head.center .eyebrow { justify-content: center; }
.sec-head.center .eyebrow::before { display: none; }
.sec-head.center .eyebrow::after { content: ""; width: 26px; height: 2px; background: var(--grad); }
.sec-head .lead { margin-top: 12px; }

/* ---------- Cards ---------- */
.grid { display: grid; gap: 22px; }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }

.card {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 26px;
  display: flex;
  flex-direction: column;
  gap: 12px;
  transition: transform .2s, border-color .2s, box-shadow .2s;
}
.card:hover {
  transform: translateY(-4px);
  border-color: var(--line-2);
  box-shadow: var(--shadow);
}
.card .ic {
  width: 46px; height: 46px;
  border-radius: 10px;
  display: grid; place-items: center;
  background: linear-gradient(135deg, rgba(46,134,255,.14), rgba(47,214,255,.1));
  border: 1px solid var(--line-2);
}
.card .ic svg { width: 24px; height: 24px; }
.card h3 { font-size: 18px; }
.card p { color: var(--muted); font-size: 14.5px; flex: 1; }
.card .more { color: var(--accent); font-weight: 600; font-size: 13.5px; display: inline-flex; align-items: center; gap: 6px; }
.card .more::after { content: "→"; transition: transform .2s; }
.card:hover .more::after { transform: translateX(4px); }

/* product card with image strip */
.card-img {
  height: 150px;
  border-radius: 10px;
  background-size: cover;
  background-position: center;
  background-color: #e4eef9;
  border: 1px solid var(--line);
  position: relative;
  overflow: hidden;
}
.card-img::after {
  content: "";
  position: absolute; inset: 0;
  background: linear-gradient(180deg, transparent 60%, rgba(228, 238, 249, .55));
}
.card-tag {
  position: absolute; top: 12px; left: 12px; z-index: 2;
  font-size: 11px; font-weight: 700; letter-spacing: .08em; text-transform: uppercase;
  color: #ffffff;
  background: var(--grad);
  padding: 4px 10px; border-radius: 20px;
}

/* ---------- Features (why us) ---------- */
.feat { display: flex; gap: 16px; }
.feat .ic { flex: none; }
.feat b { font-family: var(--font-display); font-size: 17px; text-transform: uppercase; letter-spacing: .02em; }
.feat p { color: var(--muted); font-size: 14.5px; margin-top: 4px; }

/* ---------- Spec table ---------- */
.spec-wrap {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
  background: #ffffff;
}
.spec-table { width: 100%; border-collapse: collapse; font-size: 14.5px; }
.spec-table th, .spec-table td { text-align: left; padding: 13px 18px; border-bottom: 1px solid var(--line); }
.spec-table thead th {
  background: var(--panel-2);
  font-family: var(--font-display);
  font-size: 13px; letter-spacing: .08em; text-transform: uppercase;
  color: var(--accent);
}
.spec-table tbody tr:nth-child(even) { background: rgba(228, 238, 249, .5); }
.spec-table tbody tr:last-child td { border-bottom: 0; }
.spec-table td:first-child { color: var(--muted); width: 38%; }
.spec-table td b { color: var(--text); font-family: var(--font-display); font-size: 15.5px; letter-spacing: .01em; }

/* ---------- Steps (process) ---------- */
.steps { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; counter-reset: step; }
.step {
  position: relative;
  background: #ffffff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 26px 22px 22px;
}
.step::before {
  counter-increment: step;
  content: "0" counter(step);
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 34px;
  line-height: 1;
  background: var(--grad);
  -webkit-background-clip: text; background-clip: text;
  -webkit-text-fill-color: transparent; color: transparent;
  display: block;
  margin-bottom: 12px;
}
.step b { font-family: var(--font-display); font-size: 17px; text-transform: uppercase; display: block; margin-bottom: 6px; }
.step p { color: var(--muted); font-size: 14px; }

/* ---------- Page hero (inner pages) ---------- */
.page-hero { position: relative; overflow: hidden; padding: 70px 0 56px; border-bottom: 1px solid var(--line); background: linear-gradient(180deg, #eef5fc 0%, var(--bg) 100%); }
.page-hero::before {
  content: "";
  position: absolute; inset: 0;
  background: radial-gradient(800px 400px at 80% -20%, rgba(46, 134, 255, .12), transparent 60%);
  pointer-events: none;
}
.page-hero::after {
  content: "";
  position: absolute; inset: 0;
  background-image: linear-gradient(rgba(47, 214, 255, .08) 1px, transparent 1px),
                    linear-gradient(90deg, rgba(47, 214, 255, .08) 1px, transparent 1px);
  background-size: 48px 48px;
  mask-image: radial-gradient(900px 320px at 60% 0%, #000, transparent 80%);
  -webkit-mask-image: radial-gradient(900px 320px at 60% 0%, #000, transparent 80%);
  pointer-events: none;
}
.page-hero .container { position: relative; z-index: 1; }
.page-hero h1 { font-size: clamp(28px, 4vw, 44px); }
.breadcrumb { font-size: 13px; color: var(--dim); margin-bottom: 16px; }
.breadcrumb a { color: var(--muted); }
.breadcrumb a:hover { color: var(--accent); }

/* ---------- CTA band ---------- */
.cta-band {
  position: relative;
  overflow: hidden;
  padding: 70px 0;
  border-top: 1px solid var(--line);
  background: linear-gradient(135deg, #eaf3fd 0%, #f7fbff 100%);
}
.cta-band::before {
  content: "";
  position: absolute; inset: 0;
  background:
    radial-gradient(760px 360px at 50% -40%, rgba(255, 138, 42, .12), transparent 60%),
    radial-gradient(900px 420px at 90% 120%, rgba(46, 134, 255, .14), transparent 60%);
  pointer-events: none;
}
.cta-band::after {
  content: "";
  position: absolute; inset: 0;
  background-image: linear-gradient(rgba(47, 214, 255, .07) 1px, transparent 1px),
                    linear-gradient(90deg, rgba(47, 214, 255, .07) 1px, transparent 1px);
  background-size: 44px 44px;
  pointer-events: none;
}
.cta-inner { position: relative; z-index: 1; text-align: center; max-width: 780px; margin: 0 auto; }
.cta-inner h2 { margin-bottom: 14px; }
.cta-inner .lead { margin: 0 auto 28px; }
.cta-inner .hero-cta { justify-content: center; }

/* ---------- Footer ---------- */
.site-footer { border-top: 1px solid var(--line); background: #eaf2fb; padding: 60px 0 0; }
.footer-grid { display: grid; grid-template-columns: 1.4fr 1fr 1fr 1.2fr; gap: 40px; padding-bottom: 44px; }
.footer-brand .brand { margin-bottom: 16px; }
.footer-brand p { color: var(--muted); font-size: 14px; max-width: 320px; }
.footer-col h4 {
  font-size: 13px; letter-spacing: .14em; text-transform: uppercase;
  color: var(--accent); margin-bottom: 16px;
}
.footer-col ul { display: flex; flex-direction: column; gap: 9px; }
.footer-col a, .footer-col li { color: var(--muted); font-size: 14px; }
.footer-col a:hover { color: var(--brand); }
.footer-col li { display: flex; gap: 8px; align-items: flex-start; }
.footer-col li svg { flex: none; width: 16px; height: 16px; margin-top: 3px; }
.footer-bottom {
  border-top: 1px solid var(--line);
  padding: 20px 0;
  display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; gap: 10px;
  color: var(--dim); font-size: 13px;
}

/* ---------- Modal ---------- */
.modal-overlay {
  position: fixed; inset: 0; z-index: 200;
  background: rgba(13, 31, 51, .55);
  backdrop-filter: blur(6px);
  display: grid; place-items: center;
  padding: 20px;
  opacity: 0; visibility: hidden;
  transition: opacity .25s, visibility .25s;
}
.modal-overlay.open { opacity: 1; visibility: visible; }
.modal {
  width: min(520px, 100%);
  background: #ffffff;
  border: 1px solid var(--line-2);
  border-radius: 16px;
  padding: 30px;
  position: relative;
  transform: translateY(16px);
  transition: transform .25s;
}
.modal-overlay.open .modal { transform: translateY(0); }
.modal h3 { margin-bottom: 6px; }
.modal .close-btn {
  position: absolute; top: 16px; right: 16px;
  background: none; border: 0; color: var(--dim);
  font-size: 24px; cursor: pointer; line-height: 1;
}
.modal .close-btn:hover { color: var(--text); }
.modal p { color: var(--muted); font-size: 14px; margin-bottom: 20px; }

.form-group { margin-bottom: 14px; }
.form-group label { display: block; font-size: 12.5px; color: var(--muted); margin-bottom: 6px; letter-spacing: .04em; text-transform: uppercase; }
.form-group input, .form-group select, .form-group textarea {
  width: 100%;
  background: var(--bg);
  border: 1px solid var(--line-2);
  border-radius: 8px;
  color: var(--text);
  padding: 11px 14px;
  font-family: var(--font-body);
  font-size: 14.5px;
  transition: border-color .2s;
}
.form-group input:focus, .form-group select:focus, .form-group textarea:focus {
  outline: none; border-color: var(--accent);
}
.form-group textarea { resize: vertical; min-height: 90px; }
.form-note { color: var(--dim); font-size: 12.5px; margin-top: 12px; }

/* ---------- Toast ---------- */
.toast {
  position: fixed; left: 50%; bottom: 28px; transform: translate(-50%, 20px);
  background: #ffffff; color: var(--text);
  border: 1px solid var(--line-2);
  box-shadow: var(--shadow);
  padding: 12px 22px; border-radius: 8px;
  font-size: 14px; z-index: 300;
  opacity: 0; visibility: hidden;
  transition: opacity .25s, transform .25s, visibility .25s;
}
.toast.show { opacity: 1; visibility: visible; transform: translate(-50%, 0); }

/* ---------- Two-column detail layout ---------- */
.detail-layout { display: grid; grid-template-columns: 1.15fr .85fr; gap: 34px; align-items: start; }
.side-sticky { position: sticky; top: 96px; display: flex; flex-direction: column; gap: 16px; }
.side-card {
  background: #ffffff; border: 1px solid var(--line);
  border-radius: var(--radius); padding: 22px;
}
.side-card h4 { font-size: 14px; letter-spacing: .1em; text-transform: uppercase; color: var(--accent); margin-bottom: 12px; }
.side-card .row { display: flex; justify-content: space-between; gap: 10px; padding: 9px 0; border-bottom: 1px dashed var(--line); font-size: 14px; }
.side-card .row:last-child { border-bottom: 0; }
.side-card .row span { color: var(--muted); }
.side-card .row b { font-family: var(--font-display); color: var(--brand); }

.check-list { display: flex; flex-direction: column; gap: 10px; }
.check-list li { display: flex; gap: 10px; color: var(--muted); font-size: 14.5px; }
.check-list li svg { flex: none; width: 18px; height: 18px; margin-top: 3px; }

/* ---------- Contact page ---------- */
.contact-grid { display: grid; grid-template-columns: .9fr 1.1fr; gap: 34px; align-items: start; }
.contact-grid .side-card h3 { font-size: 16px; margin-bottom: 18px; }
.contact-list { display: flex; flex-direction: column; gap: 18px; }
.contact-list li { display: flex; gap: 14px; align-items: flex-start; }
.contact-list svg { flex: none; width: 22px; height: 22px; margin-top: 2px; }
.contact-list strong { display: block; font-size: 13px; color: var(--text); margin-bottom: 2px; }
.contact-list span { color: var(--muted); font-size: 14.5px; }
.form-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 0 18px; }
.map-placeholder {
  display: grid; place-items: center; gap: 14px;
  min-height: 220px;
  border: 1px dashed var(--line-2);
  border-radius: var(--radius);
  background: rgba(255, 255, 255, .6);
  color: var(--muted);
  font-size: 14px;
  text-align: center;
  padding: 30px;
}
.map-placeholder svg { width: 40px; height: 40px; opacity: .6; }

/* ---------- Reveal on scroll ---------- */
[data-reveal] { opacity: 0; transform: translateY(24px); transition: opacity .6s ease, transform .6s ease; }
[data-reveal].revealed { opacity: 1; transform: translateY(0); }
@media (prefers-reduced-motion: reduce) {
  [data-reveal] { opacity: 1; transform: none; transition: none; }
}

/* ---------- Responsive ---------- */
@media (max-width: 960px) {
  .hero-inner { grid-template-columns: 1fr; gap: 34px; }
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .grid-3 { grid-template-columns: repeat(2, 1fr); }
  .steps { grid-template-columns: repeat(2, 1fr); }
  .detail-layout { grid-template-columns: 1fr; }
  .side-sticky { position: static; }
  .metric-row { grid-template-columns: repeat(2, 1fr); }
  .contact-grid { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 680px) {
  .nav {
    position: fixed; inset: 72px 0 auto 0;
    flex-direction: column;
    background: rgba(255, 255, 255, .98);
    border-bottom: 1px solid var(--line);
    padding: 18px 24px 26px;
    gap: 2px;
    transform: translateY(-12px);
    opacity: 0; visibility: hidden;
    transition: transform .25s, opacity .25s, visibility .25s;
  }
  .nav.open { transform: translateY(0); opacity: 1; visibility: visible; }
  .nav a { padding: 12px 6px; font-size: 16px; border-bottom: 1px solid rgba(215, 229, 244, .7); border-radius: 0; }
  .nav-toggle { display: flex; }
  .header-actions .btn-sm { display: none; }
  .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
  .steps { grid-template-columns: 1fr; }
  .hero-metrics { grid-template-columns: repeat(3, 1fr); gap: 10px; }
  .metric { padding: 14px 10px; }
  .metric b { font-size: 20px; }
  .footer-grid { grid-template-columns: 1fr; gap: 28px; }
  .section { padding: 60px 0; }
}