/* ============================================================
   QINQI ROBOTICS — English site design system
   Industrial B2B aesthetic: restrained, technical, trustworthy.
   Light theme only. Mobile-first responsive.
   ============================================================ */

:root {
  --bg: #ffffff;
  --bg-alt: #f5f7f9;
  --bg-dark: #0e1524;
  --ink: #161b22;
  --ink-2: #454f5b;
  --ink-3: #6a7380;
  --line: #e3e8ed;
  --brand: #0b4f8c;
  --brand-2: #0d6ebd;
  --brand-soft: #eaf2f9;
  --accent: #d97706;
  --ok: #1a7f37;
  --danger: #c92a2a;
  --radius: 10px;
  --radius-lg: 16px;
  --shadow: 0 1px 2px rgba(16, 24, 40, .05), 0 8px 24px rgba(16, 24, 40, .06);
  --shadow-lg: 0 2px 4px rgba(16, 24, 40, .06), 0 20px 48px rgba(16, 24, 40, .10);
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", sans-serif;
  --container: 1140px;
}

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

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

body {
  font-family: var(--font);
  color: var(--ink);
  background: var(--bg);
  line-height: 1.6;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}

img, svg { display: block; max-width: 100%; }

a { color: var(--brand); text-decoration: none; }
a:hover { text-decoration: none; }

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

/* ---------- Typography ---------- */
h1, h2, h3 { line-height: 1.15; font-weight: 700; letter-spacing: -0.015em; }
h1 { font-size: clamp(2rem, 4.4vw, 3.1rem); }
h2 { font-size: clamp(1.55rem, 3vw, 2.1rem); }
h3 { font-size: 1.15rem; }
p { color: var(--ink-2); }
.lead { font-size: 1.13rem; color: var(--ink-2); }
.small { font-size: .875rem; }

.section { padding: 88px 0; }
.section.alt { background: var(--bg-alt); }
.section-head { max-width: 720px; margin-bottom: 48px; }
.section-head h2 { margin-bottom: 12px; }
.section-head .kicker { text-transform: uppercase; letter-spacing: .12em; font-size: .78rem; font-weight: 700; color: var(--brand); margin-bottom: 10px; }
.section-head.center { margin-left: auto; margin-right: auto; text-align: center; }

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  font-weight: 600; font-size: .98rem; border-radius: 8px;
  padding: 13px 26px; border: 1.5px solid transparent; cursor: pointer;
  transition: all .18s ease; white-space: nowrap; font-family: inherit;
}
.btn-primary { background: var(--brand); color: #fff; }
.btn-primary:hover { background: var(--brand-2); transform: translateY(-1px); }
.btn-outline { background: transparent; color: var(--ink); border-color: #c9d2da; }
.btn-outline:hover { border-color: var(--brand); color: var(--brand); }
.btn-white { background: #fff; color: var(--brand); }
.btn-white:hover { background: #eaf2f9; }
.btn-lg { padding: 16px 34px; font-size: 1.05rem; }

/* ---------- Nav ---------- */
.nav {
  position: sticky; top: 0; z-index: 50;
  background: rgba(255,255,255,.94); backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--line);
}
.nav-inner { display: flex; align-items: center; justify-content: space-between; height: 68px; }
.nav-logo { display: flex; align-items: center; gap: 10px; font-weight: 800; font-size: 1.12rem; color: var(--ink); letter-spacing: -.01em; }
.nav-logo .mark { width: 34px; height: 34px; border-radius: 8px; background: var(--brand); display: grid; place-items: center; color: #fff; font-weight: 800; font-size: .8rem; }
.nav-logo span b { color: var(--brand); }
.nav-links { display: flex; align-items: center; gap: 28px; list-style: none; }
.nav-links a { color: var(--ink-2); font-size: .95rem; font-weight: 500; }
.nav-links a:hover { color: var(--brand); }
.nav-cta { margin-left: 8px; padding: 10px 20px; font-size: .92rem; }
.nav-toggle { display: none; background: none; border: 0; font-size: 1.6rem; color: var(--ink); cursor: pointer; line-height: 1; }

@media (max-width: 920px) {
  .nav-links {
    display: none; position: absolute; top: 68px; left: 0; right: 0;
    background: #fff; border-bottom: 1px solid var(--line); flex-direction: column;
    align-items: flex-start; padding: 16px 24px 24px; gap: 4px;
  }
  .nav-links.open { display: flex; }
  .nav-links li { width: 100%; padding: 10px 0; border-bottom: 1px solid var(--line); }
  .nav-links li:last-child { border: 0; }
  .nav-cta { width: 100%; margin: 12px 0 0; justify-content: center; }
  .nav-toggle { display: block; }
}

/* ---------- Hero ---------- */
.hero { background: linear-gradient(180deg, #f2f6fa 0%, #ffffff 100%); border-bottom: 1px solid var(--line); overflow: hidden; }
.hero-inner { display: grid; grid-template-columns: 1.05fr .95fr; gap: 56px; align-items: center; padding: 92px 0 88px; }
.hero h1 { margin-bottom: 20px; }
.hero .lead { margin-bottom: 32px; max-width: 520px; }
.hero-ctas { display: flex; gap: 14px; flex-wrap: wrap; margin-bottom: 36px; }
.hero-points { display: flex; flex-wrap: wrap; gap: 10px 24px; list-style: none; }
.hero-points li { font-size: .92rem; font-weight: 600; color: var(--ink-2); display: flex; align-items: center; gap: 8px; }
.hero-points .tick { color: var(--ok); font-weight: 800; }

.hero-visual { position: relative; }
.hero-card {
  background: #fff; border: 1px solid var(--line); border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg); padding: 28px;
}
.hero-card .label { text-transform: uppercase; letter-spacing: .1em; font-size: .72rem; font-weight: 700; color: var(--ink-3); margin-bottom: 14px; }
.hero-card .metric { font-size: 1.9rem; font-weight: 800; letter-spacing: -.02em; }
.hero-card .metric small { font-size: .95rem; font-weight: 600; color: var(--ink-3); }
.hero-card .row { display: flex; justify-content: space-between; align-items: baseline; padding: 12px 0; border-bottom: 1px dashed var(--line); }
.hero-card .row:last-child { border: 0; }
.hero-badge {
  position: absolute; top: -18px; right: -8px; background: var(--brand); color: #fff;
  font-size: .78rem; font-weight: 700; padding: 8px 14px; border-radius: 999px; box-shadow: var(--shadow);
}

/* ---------- Trust band ---------- */
.trust-band { border-bottom: 1px solid var(--line); background: #fff; }
.trust-inner { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; padding: 28px 0; }
.trust-item { display: flex; gap: 12px; align-items: center; }
.trust-item .ic { width: 40px; height: 40px; border-radius: 10px; background: var(--brand-soft); display: grid; place-items: center; flex-shrink: 0; }
.trust-item b { font-size: .95rem; display: block; line-height: 1.3; }
.trust-item span { font-size: .8rem; color: var(--ink-3); }
@media (max-width: 860px) { .trust-inner { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 480px) { .trust-inner { grid-template-columns: 1fr; } }

/* ---------- Cards / grids ---------- */
.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 28px; }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.grid-6 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
@media (max-width: 900px) { .grid-2, .grid-3, .grid-6 { grid-template-columns: 1fr; } }

.card {
  background: #fff; border: 1px solid var(--line); border-radius: var(--radius);
  padding: 28px; transition: all .2s ease;
}
.card:hover { box-shadow: var(--shadow-lg); transform: translateY(-2px); }
.card h3 { margin-bottom: 10px; }
.card p { font-size: .94rem; }
.card .tag-row { display: flex; gap: 8px; flex-wrap: wrap; margin-top: 16px; }

.tag { display: inline-block; font-size: .74rem; font-weight: 700; color: var(--brand); background: var(--brand-soft); border-radius: 6px; padding: 4px 10px; letter-spacing: .02em; }
.tag.green { color: var(--ok); background: #e8f6ee; }
.tag.amber { color: #9a6b00; background: #fdf3e0; }

/* ---------- Scenario cards (home) ---------- */
.scene-card { position: relative; overflow: hidden; display: block; color: inherit; }
.scene-card .top { display: flex; justify-content: space-between; align-items: center; margin-bottom: 14px; }
.scene-card .ic { width: 46px; height: 46px; border-radius: 12px; background: var(--brand-soft); display: grid; place-items: center; }
.scene-card .kw { font-size: .72rem; font-weight: 700; color: var(--ink-3); background: var(--bg-alt); border: 1px solid var(--line); padding: 4px 9px; border-radius: 999px; }
.scene-card h3 { font-size: 1.08rem; }
.scene-card ul { margin: 14px 0 18px; list-style: none; }
.scene-card ul li { font-size: .88rem; color: var(--ink-2); padding: 5px 0 5px 22px; position: relative; }
.scene-card ul li::before { content: "✓"; position: absolute; left: 0; color: var(--ok); font-weight: 800; }
.scene-card .more { font-weight: 700; font-size: .9rem; color: var(--brand); display: inline-flex; align-items: center; gap: 6px; }

/* ---------- Feature list ---------- */
.checklist { list-style: none; }
.checklist li { padding: 7px 0 7px 28px; position: relative; color: var(--ink-2); }
.checklist li::before { content: "✓"; position: absolute; left: 0; top: 7px; width: 20px; height: 20px; border-radius: 50%; background: #e8f6ee; color: var(--ok); font-weight: 800; font-size: .72rem; display: grid; place-items: center; }
.checklist li b { color: var(--ink); }

/* ---------- Spec table ---------- */
.spec-table { width: 100%; border-collapse: collapse; background: #fff; border: 1px solid var(--line); border-radius: var(--radius); overflow: hidden; }
.spec-table th, .spec-table td { text-align: left; padding: 14px 18px; border-bottom: 1px solid var(--line); font-size: .93rem; }
.spec-table th { background: var(--bg-alt); font-weight: 700; color: var(--ink); white-space: nowrap; width: 34%; }
.spec-table tr:last-child td { border-bottom: 0; }
.spec-table td { color: var(--ink-2); }

/* ---------- Stats ---------- */
.stats { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; }
.stat { text-align: center; padding: 10px; }
.stat .num { font-size: 2.2rem; font-weight: 800; letter-spacing: -.02em; color: var(--brand); line-height: 1.1; }
.stat .lbl { font-size: .86rem; color: var(--ink-3); margin-top: 4px; }
@media (max-width: 800px) { .stats { grid-template-columns: repeat(2, 1fr); } }

/* ---------- Steps / process ---------- */
.steps { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; counter-reset: step; }
.step { position: relative; padding: 26px 24px 26px 26px; background: #fff; border: 1px solid var(--line); border-radius: var(--radius); }
.step::before { counter-increment: step; content: "0" counter(step); font-size: 2rem; font-weight: 800; color: var(--brand-soft); line-height: 1; display: block; margin-bottom: 12px; letter-spacing: -.03em; }
.step h3 { font-size: 1.02rem; margin-bottom: 8px; }
.step p { font-size: .9rem; }
@media (max-width: 900px) { .steps { grid-template-columns: 1fr; } }

/* ---------- CTA band ---------- */
.cta-band { background: var(--bg-dark); color: #fff; padding: 72px 0; }
.cta-band h2 { color: #fff; margin-bottom: 14px; }
.cta-band p { color: #aeb8c5; max-width: 640px; margin-bottom: 28px; }
.cta-band .btn-wrap { display: flex; gap: 14px; flex-wrap: wrap; }
.cta-email { display: inline-flex; align-items: center; gap: 8px; color: #dce6f2; font-weight: 600; margin-top: 20px; font-size: .95rem; }

/* ---------- Case snippet ---------- */
.case-snippet { display: flex; gap: 22px; align-items: flex-start; background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 26px; }
.case-snippet .side { flex-shrink: 0; width: 96px; height: 96px; border-radius: 10px; background: var(--brand-soft); display: grid; place-items: center; }
.case-snippet h3 { font-size: 1.02rem; margin-bottom: 6px; }
.case-snippet .meta { font-size: .8rem; color: var(--ink-3); margin-bottom: 8px; }
.case-snippet p { font-size: .9rem; }
@media (max-width: 600px) { .case-snippet { flex-direction: column; } }

/* ---------- Page hero (sub pages) ---------- */
.page-hero { background: linear-gradient(180deg, #eef3f8 0%, #ffffff 100%); border-bottom: 1px solid var(--line); padding: 72px 0 64px; }
.page-hero .crumb { font-size: .8rem; font-weight: 600; color: var(--ink-3); margin-bottom: 14px; }
.page-hero .crumb a { color: var(--ink-3); }
.page-hero .crumb a:hover { color: var(--brand); }
.page-hero h1 { max-width: 760px; margin-bottom: 16px; }
.page-hero .lead { max-width: 640px; }
.page-hero .tags { display: flex; gap: 8px; flex-wrap: wrap; margin-top: 22px; }

/* ---------- Split feature ---------- */
.split { display: grid; grid-template-columns: 1fr 1fr; gap: 56px; align-items: center; }
.split .visual { order: 2; }
.split:nth-child(even) .visual { order: 1; }
.split .visual { background: var(--brand-soft); border: 1px solid var(--line); border-radius: var(--radius-lg); min-height: 320px; display: grid; place-items: center; padding: 24px; }
@media (max-width: 900px) { .split { grid-template-columns: 1fr; gap: 32px; } .split .visual, .split:nth-child(even) .visual { order: -1; min-height: 200px; } }

/* ---------- Alert / note ---------- */
.note { border-left: 4px solid var(--brand); background: var(--brand-soft); border-radius: 0 var(--radius) var(--radius) 0; padding: 18px 22px; margin: 20px 0; font-size: .93rem; color: var(--ink-2); }
.note.warn { border-color: var(--accent); background: #fdf3e0; }

/* ---------- Form ---------- */
.form-card { background: #fff; border: 1px solid var(--line); border-radius: var(--radius-lg); padding: 36px; box-shadow: var(--shadow); }
.form-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 18px; }
.form-group { display: flex; flex-direction: column; gap: 6px; }
.form-group.full { grid-column: 1 / -1; }
.form-group label { font-size: .86rem; font-weight: 600; color: var(--ink); }
.form-group input, .form-group select, .form-group textarea {
  font-family: inherit; font-size: .95rem; color: var(--ink); padding: 12px 14px;
  border: 1.5px solid #cfd8e0; border-radius: 8px; background: #fff; transition: border .15s ease;
}
.form-group input:focus, .form-group select:focus, .form-group textarea:focus { outline: none; border-color: var(--brand); }
.form-group textarea { resize: vertical; min-height: 120px; }
.form-note { font-size: .8rem; color: var(--ink-3); margin-top: 14px; }
@media (max-width: 640px) { .form-grid { grid-template-columns: 1fr; } .form-card { padding: 24px; } }

/* ---------- Footer ---------- */
.footer { background: #0d1524; color: #8fa0b3; font-size: .9rem; padding: 64px 0 36px; }
.footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr 1.4fr; gap: 40px; }
.footer h4 { color: #fff; font-size: .92rem; margin-bottom: 16px; letter-spacing: .02em; }
.footer a { color: #8fa0b3; }
.footer a:hover { color: #fff; }
.footer ul { list-style: none; }
.footer ul li { padding: 5px 0; }
.footer .brand-line { font-weight: 800; color: #fff; font-size: 1.05rem; display: flex; align-items: center; gap: 10px; margin-bottom: 14px; }
.footer .brand-line .mark { width: 30px; height: 30px; border-radius: 7px; background: var(--brand); color: #fff; display: grid; place-items: center; font-size: .72rem; font-weight: 800; }
.footer .copy { border-top: 1px solid #243044; margin-top: 48px; padding-top: 24px; font-size: .8rem; display: flex; justify-content: space-between; flex-wrap: wrap; gap: 10px; }
@media (max-width: 900px) { .footer-grid { grid-template-columns: 1fr 1fr; } }
@media (max-width: 560px) { .footer-grid { grid-template-columns: 1fr; } }

/* ---------- Utilities ---------- */
.mt-16 { margin-top: 16px; } .mt-24 { margin-top: 24px; } .mt-40 { margin-top: 40px; }
.mb-24 { margin-bottom: 24px; } .mb-40 { margin-bottom: 40px; }
.center { text-align: center; }
.hidden { display: none; }