/* ==========================================================================
   HubBuyCN Spreadsheet — Public Sheet / Private Folio theme
   Cool light grey · deep navy · public teal · private indigo · safety orange · coral
   ========================================================================== */

:root {
  /* palette */
  --grey:        #F0F2F5;
  --grey-2:      #E6E9EE;
  --grey-3:      #D9DEE6;
  --ink:         #182845;
  --ink-2:       #122038;
  --ink-soft:    #46546E;
  --ink-faint:   #8B95A8;
  --teal:        #1FA3A0;
  --teal-d:      #177F7C;
  --teal-s:      #DDF1F0;
  --indigo:      #34306E;
  --indigo-d:    #27245A;
  --indigo-s:    #E4E3F5;
  --orange:      #E0701A;
  --orange-d:    #C05E12;
  --orange-s:    #FCE8D6;
  --coral:       #D95050;
  --coral-s:     #FBE3E3;
  --line:        #DDE1E7;
  --line-soft:   #E9ECF1;

  /* typography */
  --serif: Georgia, 'Times New Roman', Times, serif;
  --sans: system-ui, -apple-system, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  --mono: ui-monospace, SFMono-Regular, 'SF Mono', Menlo, Consolas, monospace;

  /* geometry */
  --radius: 14px;
  --radius-sm: 8px;
  --container: 1140px;
  --shadow-sm: 0 1px 2px rgba(24, 40, 69, 0.05), 0 2px 8px rgba(24, 40, 69, 0.06);
  --shadow-md: 0 4px 14px rgba(24, 40, 69, 0.10), 0 12px 32px rgba(24, 40, 69, 0.08);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  font-family: var(--sans);
  font-size: 16.5px;
  line-height: 1.65;
  color: var(--ink);
  background: var(--grey);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

/* ---------- accessibility ---------- */
.skip-link { position: absolute; left: -9999px; top: 0; background: var(--ink); color: #fff; padding: 10px 16px; z-index: 200; border-radius: 0 0 var(--radius-sm) 0; }
.skip-link:focus { left: 0; }
:focus-visible { outline: 3px solid var(--teal); outline-offset: 2px; border-radius: 3px; }
.visually-hidden { position: absolute !important; width: 1px; height: 1px; margin: -1px; padding: 0; border: 0; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }

/* ---------- layout ---------- */
.container { max-width: var(--container); margin: 0 auto; padding: 0 22px; }

/* ---------- header ---------- */
.site-header { position: sticky; top: 0; z-index: 100; background: rgba(240, 242, 245, 0.92); backdrop-filter: saturate(140%) blur(8px); border-bottom: 1px solid var(--line-soft); }
.header-inner { display: flex; align-items: center; gap: 20px; height: 66px; }
.brand { display: flex; align-items: center; gap: 11px; text-decoration: none; color: var(--ink); }
.brand img { width: 34px; height: 34px; display: block; border-radius: 7px; }
.brand-name { font-family: var(--serif); font-weight: 700; font-size: 1.06rem; letter-spacing: 0.01em; }
.brand-name small { display: block; font-family: var(--sans); font-weight: 600; font-size: 0.66rem; color: var(--ink-faint); letter-spacing: 0.14em; text-transform: uppercase; }

.main-nav { margin-left: auto; }
.main-nav ul { display: flex; align-items: center; gap: 4px; list-style: none; margin: 0; padding: 0; }
.main-nav a { display: block; padding: 8px 12px; text-decoration: none; color: var(--ink-soft); font-weight: 600; font-size: 0.9rem; border-radius: var(--radius-sm); }
.main-nav a:hover { background: var(--grey-2); color: var(--ink); }
.main-nav a.active { color: var(--orange-d); background: var(--orange-s); }

.mobile-nav-toggle { display: none; margin-left: auto; width: 44px; height: 44px; border: 1px solid var(--line); background: #fff; border-radius: var(--radius-sm); cursor: pointer; color: var(--ink); }
.mobile-nav-toggle svg { display: block; margin: 0 auto; }

@media (max-width: 860px) {
  .main-nav { display: none; }
  .mobile-nav-toggle { display: block; }
  .main-nav.open { display: block; position: absolute; left: 0; right: 0; top: 66px; background: #fff; border-bottom: 1px solid var(--line); box-shadow: var(--shadow-md); }
  .main-nav.open ul { flex-direction: column; align-items: stretch; gap: 2px; padding: 8px; }
  .main-nav.open a { padding: 12px 14px; }
}

/* ---------- buttons ---------- */
.btn { display: inline-flex; align-items: center; justify-content: center; gap: 8px; padding: 12px 22px; border-radius: 999px; text-decoration: none; font-weight: 700; font-size: 0.98rem; line-height: 1.2; border: 1.5px solid transparent; transition: transform 0.12s ease, box-shadow 0.12s ease, background 0.12s ease; }
.btn:active { transform: translateY(1px); }
.btn-primary { background: var(--orange); color: #fff; box-shadow: 0 4px 14px rgba(224, 112, 26, 0.30); }
.btn-primary:hover { background: var(--orange-d); box-shadow: 0 6px 18px rgba(224, 112, 26, 0.38); }
.btn-secondary { background: #fff; color: var(--ink); border-color: var(--line); box-shadow: var(--shadow-sm); }
.btn-secondary:hover { border-color: var(--ink-soft); background: #fff; }
.btn-sm { padding: 9px 16px; font-size: 0.88rem; }

/* ---------- hero ---------- */
.hero-section { padding: 56px 0 44px; position: relative; overflow: hidden; background: radial-gradient(circle at 85% 8%, var(--teal-s) 0, transparent 42%), radial-gradient(circle at 6% 92%, var(--indigo-s) 0, transparent 40%); }
.hero-grid { display: grid; grid-template-columns: 1.05fr 0.95fr; gap: 44px; align-items: center; }
.hero-badge { display: inline-block; padding: 5px 13px; border-radius: 999px; background: var(--indigo-s); color: var(--indigo-d); font-weight: 700; font-size: 0.76rem; letter-spacing: 0.08em; text-transform: uppercase; }
.hero-title { font-family: var(--serif); font-size: clamp(2.05rem, 4.6vw, 3.1rem); line-height: 1.12; color: var(--ink-2); margin: 18px 0 16px; font-weight: 700; }
.hero-title em { font-style: normal; color: var(--teal-d); }
.hero-description { font-size: 1.08rem; color: var(--ink-soft); max-width: 34em; margin: 0 0 26px; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 12px; }

/* hero vertically-split workbench */
.hero-visual { position: relative; }
.workspace-hero { display: grid; grid-template-columns: 1fr 30px 1fr; align-items: stretch; }
.ws-half { position: relative; border-radius: 12px; padding: 18px 14px 16px; min-height: 210px; box-shadow: var(--shadow-md); }
.ws-public { background: #fff; border: 1px solid var(--teal); }
.ws-private { background: var(--indigo-s); border: 1px solid var(--indigo); }
.ws-label { font-family: var(--mono); font-size: 0.7rem; font-weight: 800; letter-spacing: 0.12em; text-transform: uppercase; margin-bottom: 14px; }
.ws-public .ws-label { color: var(--teal-d); }
.ws-private .ws-label { color: var(--indigo-d); }
.ws-folder, .ws-folio { display: flex; align-items: center; gap: 10px; font-size: 0.85rem; }
.ws-public .ws-folder { color: var(--ink-soft); }
.ws-private .ws-folio { color: var(--indigo-d); }
.ws-folder svg, .ws-folio svg { flex: none; }
.ws-boundary { display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 5px; }
.ws-boundary .bd { width: 4px; height: 4px; border-radius: 50%; background: var(--ink-faint); }
.ws-boundary::before { content: ""; position: absolute; width: 0; height: 100%; border-left: 2px dashed var(--ink-faint); left: 50%; transform: translateX(-50%); }

@media (max-width: 860px) {
  .hero-grid { grid-template-columns: 1fr; gap: 26px; }
  .hero-section { padding-top: 34px; }
}

/* ---------- section scaffolding ---------- */
.section { padding: 46px 0; }
.section-alt { background: var(--grey-2); }
.section-header { max-width: 680px; margin: 0 auto 34px; text-align: center; }
.eyebrow { display: inline-block; font-size: 0.76rem; font-weight: 700; letter-spacing: 0.14em; text-transform: uppercase; color: var(--teal-d); }
.section-title { font-family: var(--serif); font-size: clamp(1.6rem, 3.4vw, 2.15rem); color: var(--ink-2); margin: 10px 0 12px; line-height: 1.2; }
.section-lead { color: var(--ink-soft); font-size: 1.02rem; margin: 0; }

/* ---------- category grid (public reference index folders) ---------- */
.categories-section { padding-top: 10px; }
.cat-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 14px; }
.cat-card {
  position: relative; display: flex; flex-direction: column; gap: 9px;
  background: #fff; border: 1px solid var(--line); border-radius: var(--radius);
  padding: 20px 16px 14px; text-decoration: none; color: var(--ink);
  box-shadow: var(--shadow-sm); transition: transform 0.14s ease, box-shadow 0.14s ease, border-color 0.14s ease;
}
.cat-card:hover { transform: translateY(-3px); box-shadow: var(--shadow-md); border-color: var(--teal); }
.cat-tab { position: absolute; top: -1px; left: 14px; padding: 3px 11px; border-radius: 0 0 7px 7px; font-family: var(--mono); font-size: 0.68rem; font-weight: 800; letter-spacing: 0.08em; text-transform: uppercase; color: #fff; background: var(--teal); }
.cat-icon { width: 28px; height: 28px; color: var(--teal-d); }
.cat-icon svg { width: 100%; height: 100%; }
.cat-name { font-weight: 700; color: var(--ink-2); font-size: 0.97rem; line-height: 1.3; }
.cat-card .cat-arrow { margin-top: auto; font-size: 0.8rem; font-weight: 700; color: var(--teal-d); }

@media (max-width: 900px) {
  .cat-grid { grid-template-columns: repeat(2, 1fr); gap: 12px; }
  .cat-card { padding: 18px 13px 12px; }
}

/* ---------- public / private module ---------- */
.pp-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; max-width: 900px; margin: 0 auto; }
.pp-col { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 22px 24px; }
.pp-col.pp-public { border-top: 4px solid var(--teal); }
.pp-col.pp-private { border-top: 4px solid var(--indigo); }
.pp-col h3 { display: flex; align-items: center; gap: 9px; margin: 0 0 12px; font-family: var(--serif); font-size: 1.2rem; color: var(--ink-2); }
.pp-col .pp-tag { flex: none; font-family: var(--mono); font-size: 0.66rem; font-weight: 800; letter-spacing: 0.08em; text-transform: uppercase; padding: 3px 8px; border-radius: 5px; color: #fff; }
.pp-public .pp-tag { background: var(--teal); }
.pp-private .pp-tag { background: var(--indigo); }
.pp-col ul { margin: 0; padding-left: 18px; color: var(--ink-soft); font-size: 0.94rem; }
.pp-col ul li { margin: 7px 0; }
@media (max-width: 720px) { .pp-grid { grid-template-columns: 1fr; } }

.boundary-note { display: flex; align-items: center; justify-content: center; gap: 8px; margin: 16px auto 0; max-width: 560px; text-align: center; font-size: 0.84rem; color: var(--ink-soft); }
.boundary-note .bar { flex: none; width: 26px; height: 6px; background: var(--ink-faint); border-radius: 3px; opacity: 0.5; }

/* ---------- signatures ---------- */
.redaction-bar { display: inline-block; min-width: 70px; height: 13px; background: var(--ink-2); border-radius: 3px; vertical-align: middle; }
.permission-stamp { display: inline-block; font-family: var(--mono); font-size: 0.66rem; font-weight: 800; letter-spacing: 0.08em; text-transform: uppercase; padding: 4px 10px; border: 2px solid var(--indigo); color: var(--indigo-d); border-radius: 4px; transform: rotate(-3deg); }
.classification-label { display: inline-block; font-family: var(--mono); font-size: 0.66rem; font-weight: 800; letter-spacing: 0.08em; text-transform: uppercase; padding: 3px 9px; border-radius: 5px; color: #fff; }
.classification-label.cl-public { background: var(--teal); }
.classification-label.cl-private { background: var(--indigo); }
.lock-outline { display: inline-flex; align-items: center; justify-content: center; width: 26px; height: 26px; border-radius: 50%; border: 2px solid var(--indigo); color: var(--indigo-d); flex: none; }

.example-flag { display: inline-block; margin-top: 14px; font-size: 0.74rem; color: var(--ink-faint); font-style: italic; border-top: 1px dashed var(--line); padding-top: 8px; }
.example-only { display: inline-block; margin-top: 14px; font-size: 0.74rem; color: var(--coral); font-style: italic; border-top: 1px dashed var(--coral); padding-top: 8px; }

.open-note { display: inline-flex; align-items: center; gap: 9px; padding: 10px 14px; border: 1px dashed var(--coral); border-radius: var(--radius-sm); background: var(--coral-s); color: #8A2A2A; font-weight: 600; font-size: 0.92rem; margin: 10px 0; }
.open-note .qmark { flex: none; width: 24px; height: 24px; border-radius: 50%; background: var(--coral); color: #fff; display: grid; place-items: center; font-weight: 800; }

/* ---------- safe-to-share / minimal note / screenshots ---------- */
.duo-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }
.duo-col { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 20px 22px; }
.duo-col h3 { margin: 0 0 10px; font-size: 1.02rem; display: flex; align-items: center; gap: 9px; color: var(--ink-2); }
.duo-col ul { margin: 0; padding-left: 18px; color: var(--ink-soft); font-size: 0.94rem; }
.duo-col ul li { margin: 6px 0; }
.duo-col .mark { flex: none; width: 22px; height: 22px; border-radius: 5px; display: grid; place-items: center; font-size: 0.78rem; color: #fff; font-family: var(--mono); }
.duo-col.is-a .mark { background: var(--teal); }
.duo-col.is-b .mark { background: var(--indigo); }
@media (max-width: 720px) { .duo-grid { grid-template-columns: 1fr; } }

/* ---------- clean handoff ---------- */
.handoff-list { list-style: none; margin: 0; padding: 0; max-width: 760px; margin-inline: auto; }
.handoff-list li { display: flex; gap: 14px; align-items: flex-start; padding: 14px 16px; margin: 10px 0; background: #fff; border: 1px solid var(--line); border-radius: var(--radius); box-shadow: var(--shadow-sm); }
.handoff-list .h-num { flex: none; width: 30px; height: 30px; border-radius: 50%; display: grid; place-items: center; color: #fff; font-weight: 800; font-size: 0.82rem; font-family: var(--mono); background: var(--teal); }
.handoff-list p { margin: 0; color: var(--ink-soft); font-size: 0.96rem; }
.handoff-list strong { color: var(--ink-2); }

/* ---------- guide entry cards ---------- */
.guide-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
.guide-card { display: flex; flex-direction: column; background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 24px 22px; text-decoration: none; color: var(--ink); box-shadow: var(--shadow-sm); transition: transform 0.14s ease, box-shadow 0.14s ease; }
.guide-card:hover { transform: translateY(-3px); box-shadow: var(--shadow-md); }
.guide-card .guide-num { font-family: var(--mono); font-size: 0.78rem; color: var(--indigo-d); letter-spacing: 0.1em; }
.guide-card h3 { font-family: var(--serif); font-size: 1.24rem; color: var(--ink-2); margin: 8px 0 10px; }
.guide-card p { color: var(--ink-soft); font-size: 0.95rem; margin: 0 0 16px; }
.guide-card .guide-cta { margin-top: auto; font-weight: 700; color: var(--orange-d); font-size: 0.9rem; }
@media (max-width: 900px) { .guide-grid { grid-template-columns: 1fr; } }

/* ---------- FAQ ---------- */
.faq-list { max-width: 760px; margin: 0 auto; }
details.faq-item { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); margin: 10px 0; box-shadow: var(--shadow-sm); overflow: hidden; }
details.faq-item summary { cursor: pointer; list-style: none; padding: 16px 20px; font-weight: 700; color: var(--ink-2); display: flex; align-items: center; justify-content: space-between; gap: 14px; }
details.faq-item summary::-webkit-details-marker { display: none; }
details.faq-item summary::after { content: "+"; font-size: 1.5rem; font-weight: 400; color: var(--orange); line-height: 1; }
details.faq-item[open] summary::after { content: "–"; }
.faq-item .faq-body { padding: 0 20px 18px; color: var(--ink-soft); font-size: 0.96rem; }
.faq-item .faq-body p { margin: 0 0 10px; }

/* ---------- final CTA ---------- */
.final-cta { background: var(--ink-2); color: #fff; border-radius: 20px; padding: 44px 40px; text-align: center; position: relative; overflow: hidden; }
.final-cta::before { content: ""; position: absolute; inset: 0; opacity: 0.35; background: radial-gradient(circle at 15% 20%, var(--teal) 0, transparent 40%), radial-gradient(circle at 85% 80%, var(--indigo) 0, transparent 40%); }
.final-cta h2 { font-family: var(--serif); font-size: clamp(1.5rem, 3.2vw, 2.1rem); margin: 0 0 12px; position: relative; }
.final-cta p { color: rgba(255,255,255,0.82); max-width: 30em; margin: 0 auto 24px; position: relative; }
.final-cta .btn-primary { position: relative; }

/* ---------- footer ---------- */
.site-footer { border-top: 1px solid var(--line); background: var(--grey-2); padding: 44px 0 30px; margin-top: 30px; }
.footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr; gap: 30px; }
.footer-brand p { color: var(--ink-soft); font-size: 0.92rem; max-width: 34em; }
.footer-col h4 { font-size: 0.78rem; letter-spacing: 0.12em; text-transform: uppercase; color: var(--ink-faint); margin: 0 0 12px; }
.footer-col ul { list-style: none; margin: 0; padding: 0; }
.footer-col a { color: var(--ink-soft); text-decoration: none; font-size: 0.94rem; line-height: 2.1; }
.footer-col a:hover { color: var(--orange-d); }
.footer-bottom { margin-top: 28px; padding-top: 20px; border-top: 1px solid var(--line-soft); font-size: 0.82rem; color: var(--ink-faint); display: flex; flex-wrap: wrap; gap: 8px 20px; justify-content: space-between; }
@media (max-width: 720px) { .footer-grid { grid-template-columns: 1fr; } }

/* ---------- article / guide pages ---------- */
.page-hero { background: radial-gradient(circle at 80% 10%, var(--indigo-s) 0, transparent 45%), var(--ink-2); color: #fff; padding: 48px 0 40px; position: relative; overflow: hidden; }
.page-hero .container { position: relative; }
.page-hero h1 { font-family: var(--serif); font-size: clamp(1.8rem, 4vw, 2.6rem); margin: 12px 0 12px; line-height: 1.15; color: #fff; }
.page-hero p { color: rgba(255,255,255,0.82); max-width: 40em; font-size: 1.05rem; }

.article-body { max-width: 760px; margin: 0 auto; padding: 40px 22px 60px; }
.article-body h2 { font-family: var(--serif); font-size: 1.5rem; color: var(--ink-2); margin: 38px 0 12px; }
.article-body h3 { font-size: 1.12rem; color: var(--ink-2); margin: 26px 0 8px; }
.article-body p { color: var(--ink-soft); margin: 0 0 16px; }
.article-body ul, .article-body ol { color: var(--ink-soft); margin: 0 0 18px; padding-left: 22px; }
.article-body li { margin: 6px 0; }
.article-body blockquote { margin: 22px 0; padding: 16px 20px; background: var(--grey-2); border-left: 4px solid var(--teal); border-radius: 0 var(--radius-sm) var(--radius-sm) 0; color: var(--ink-soft); font-family: var(--serif); font-size: 1.06rem; }

.back-link { display: inline-flex; align-items: center; gap: 6px; color: var(--teal-s); font-weight: 700; text-decoration: none; font-size: 0.9rem; margin-bottom: 6px; }
.back-link:hover { text-decoration: underline; }

/* legal pages */
.legal-body { max-width: 720px; margin: 0 auto; padding: 40px 22px 60px; }
.legal-body h1 { font-family: var(--serif); color: var(--ink-2); font-size: 2rem; margin: 0 0 6px; }
.legal-body .legal-date { color: var(--ink-faint); font-size: 0.85rem; margin-bottom: 24px; }
.legal-body h2 { font-family: var(--serif); font-size: 1.25rem; color: var(--ink-2); margin: 28px 0 8px; }
.legal-body p, .legal-body li { color: var(--ink-soft); }
.legal-body ul { padding-left: 22px; }

/* 404 */
.notfound { text-align: center; padding: 70px 22px 80px; }
.notfound .big { font-family: var(--serif); font-size: clamp(4rem, 14vw, 7rem); color: var(--ink-2); margin: 0; line-height: 1; }
.notfound h1 { font-family: var(--serif); color: var(--ink-2); margin: 8px 0 12px; }
.notfound p { color: var(--ink-soft); max-width: 30em; margin: 0 auto 24px; }