/* ============================================================
   YHSL Consulting Ltd — site styles
   Design system aligned to brand wordmark:
   navy + teal accent, soft surfaces, system sans.
   ============================================================ */

:root {
  /* Colour tokens (from logo) */
  --bg:            #ffffff;
  --bg-soft:       #f7f8fa;
  --rule:          #e2e5ea;
  --rule-strong:   #c9cdd4;

  --text:          #1a2540;
  --text-strong:   #1f3a5f;   /* navy from logo wordmark */
  --text-muted:    #6b7280;   /* muted grey from logo tagline */
  --text-faint:    #9aa1ad;

  --accent:        #3f9c8f;   /* teal from logo accent bar */
  --accent-hover:  #2c7e72;
  --accent-soft:   #e8f3f1;

  /* Typography */
  --font-sans: -apple-system, BlinkMacSystemFont, "Inter", "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-display: var(--font-sans);

  /* Spacing scale */
  --s-1: 4px;
  --s-2: 8px;
  --s-3: 12px;
  --s-4: 16px;
  --s-5: 24px;
  --s-6: 32px;
  --s-7: 48px;
  --s-8: 64px;
  --s-9: 96px;
  --s-10: 128px;

  /* Layout */
  --max-content: 720px;
  --max-wide:    1040px;
  --gutter:      32px;

  /* Motion */
  --t-fast: 0.15s ease;
  --t-med:  0.22s ease;
}

@media (max-width: 640px) {
  :root {
    --gutter: 20px;
    --s-9: 64px;
    --s-10: 80px;
  }
}

/* Reset */

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

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: 80px;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-sans);
  font-size: 17px;
  line-height: 1.65;
  font-weight: 400;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}

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

/* Layout primitives */

.wrap {
  width: 100%;
  max-width: var(--max-wide);
  margin: 0 auto;
  padding: 0 var(--gutter);
}

.col {
  max-width: var(--max-content);
}

/* ============================================================
   Header
   ============================================================ */

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: saturate(180%) blur(10px);
  -webkit-backdrop-filter: saturate(180%) blur(10px);
  border-bottom: 1px solid var(--rule);
}

.site-header .wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: var(--s-4);
  padding-bottom: var(--s-4);
  gap: var(--s-5);
}

.brand {
  display: inline-flex;
  align-items: center;
  text-decoration: none;
  color: var(--text-strong);
  flex-shrink: 0;
}

.brand svg {
  height: 30px;
  width: auto;
}

nav.primary {
  display: flex;
  align-items: center;
  gap: var(--s-6);
}

nav.primary a {
  position: relative;
  display: inline-block;
  padding: 6px 0;
  font-size: 0.94rem;
  font-weight: 500;
  letter-spacing: -0.005em;
  color: var(--text-muted);
  text-decoration: none;
  transition: color var(--t-fast);
}

nav.primary a:hover { color: var(--text-strong); }

nav.primary a[aria-current="page"] {
  color: var(--text-strong);
}

nav.primary a[aria-current="page"]::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: -1px;
  height: 2px;
  background: var(--accent);
}

@media (max-width: 540px) {
  nav.primary { gap: var(--s-4); }
  nav.primary a { font-size: 0.88rem; }
  .brand svg { height: 26px; }
}

/* ============================================================
   Eyebrow micro-cap label (echoes the logo subtitle)
   ============================================================ */

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  margin: 0 0 var(--s-5);
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--text-muted);
}

.eyebrow::before {
  content: "";
  display: inline-block;
  width: 24px;
  height: 2px;
  background: var(--accent);
  flex-shrink: 0;
}

/* ============================================================
   Hero (homepage)
   ============================================================ */

.hero {
  position: relative;
  padding: var(--s-10) 0 var(--s-9);
}

.hero .col {
  position: relative;
  padding-left: var(--s-5);
}

.hero .col::before {
  content: "";
  position: absolute;
  left: 0;
  top: 12px;
  bottom: 18px;
  width: 4px;
  background: var(--accent);
  border-radius: 2px;
}

.hero h1 {
  font-family: var(--font-display);
  font-size: clamp(2.1rem, 4.6vw, 3.1rem);
  line-height: 1.15;
  font-weight: 500;
  letter-spacing: -0.022em;
  color: var(--text-strong);
  margin: 0 0 var(--s-5);
}

.hero .lede {
  font-size: 1.18rem;
  line-height: 1.55;
  color: var(--text-muted);
  margin: 0;
  max-width: 640px;
}

/* Page head (non-homepage) */

.page-head {
  padding: var(--s-9) 0 var(--s-7);
  border-bottom: 1px solid var(--rule);
  margin-bottom: var(--s-7);
}

.page-head h1 {
  font-family: var(--font-display);
  font-size: clamp(1.9rem, 4vw, 2.6rem);
  line-height: 1.2;
  font-weight: 500;
  letter-spacing: -0.02em;
  color: var(--text-strong);
  margin: 0;
}

.page-head .lede {
  font-size: 1.1rem;
  line-height: 1.55;
  color: var(--text-muted);
  margin: var(--s-4) 0 0;
  max-width: 640px;
}

/* ============================================================
   Sections
   ============================================================ */

section.section {
  padding: var(--s-8) 0;
}

section.section.tight {
  padding: var(--s-6) 0 var(--s-8);
}

section.surface {
  background: var(--bg-soft);
  border-top: 1px solid var(--rule);
  border-bottom: 1px solid var(--rule);
}

/* ============================================================
   Body content
   ============================================================ */

main h2 {
  font-family: var(--font-display);
  font-size: 1.55rem;
  line-height: 1.3;
  font-weight: 500;
  letter-spacing: -0.012em;
  color: var(--text-strong);
  margin: 0 0 var(--s-4);
}

main h3 {
  font-size: 1.08rem;
  font-weight: 600;
  letter-spacing: -0.005em;
  color: var(--text-strong);
  margin: var(--s-6) 0 var(--s-3);
}

main p {
  margin: 0 0 var(--s-5);
  color: var(--text);
}

main p.lede {
  font-size: 1.1rem;
  color: var(--text-muted);
}

main a {
  color: var(--accent);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
  transition: color var(--t-fast);
}

main a:hover { color: var(--accent-hover); }

main .inline-link {
  display: inline-block;
  margin-top: var(--s-3);
  font-weight: 500;
  text-decoration: none;
  border-bottom: 1px solid var(--accent);
  padding-bottom: 1px;
  color: var(--text-strong);
}

main .inline-link:hover {
  color: var(--accent-hover);
  border-color: var(--accent-hover);
}

/* ============================================================
   Numbered service grid (homepage)
   ============================================================ */

.services {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--s-5);
  margin-top: var(--s-6);
}

@media (max-width: 860px) {
  .services { grid-template-columns: 1fr; }
}

.service {
  position: relative;
  padding: var(--s-5);
  background: var(--bg);
  border: 1px solid var(--rule);
  border-radius: 8px;
  transition: border-color var(--t-med), transform var(--t-med), box-shadow var(--t-med);
}

.service:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
  box-shadow: 0 8px 24px -12px rgba(31, 58, 95, 0.18);
}

.service .num {
  display: inline-block;
  margin-bottom: var(--s-3);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.18em;
  color: var(--accent);
}

.service h3 {
  margin: 0 0 var(--s-2);
  font-size: 1.06rem;
  color: var(--text-strong);
}

.service p {
  margin: 0;
  color: var(--text-muted);
  font-size: 0.96rem;
  line-height: 1.55;
}

/* ============================================================
   Full service blocks (services page)
   ============================================================ */

.service-block {
  display: grid;
  grid-template-columns: 96px 1fr;
  gap: var(--s-6);
  padding: var(--s-7) 0;
  border-top: 1px solid var(--rule);
}

.service-block:last-child {
  border-bottom: 1px solid var(--rule);
}

.service-block .num {
  padding-top: 6px;
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.18em;
  color: var(--accent);
}

.service-block h2 {
  margin: 0 0 var(--s-4);
  font-size: 1.35rem;
}

.service-block p {
  margin: 0;
  color: var(--text);
  line-height: 1.7;
}

@media (max-width: 640px) {
  .service-block {
    grid-template-columns: 1fr;
    gap: var(--s-3);
    padding: var(--s-6) 0;
  }
}

/* ============================================================
   Scope strip (about page)
   Three columns: discipline / sectors / platforms
   ============================================================ */

.scope {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--s-5);
  margin: var(--s-7) 0;
  padding: var(--s-6);
  background: var(--bg-soft);
  border: 1px solid var(--rule);
  border-radius: 8px;
}

.scope .col-item .label {
  display: block;
  margin-bottom: var(--s-2);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--accent);
}

.scope .col-item .value {
  font-size: 0.98rem;
  line-height: 1.5;
  color: var(--text-strong);
  font-weight: 500;
}

@media (max-width: 640px) {
  .scope {
    grid-template-columns: 1fr;
    gap: var(--s-4);
    padding: var(--s-5);
  }
}

/* ============================================================
   Contact card
   ============================================================ */

.contact-card {
  margin: var(--s-5) 0 var(--s-7);
  padding: var(--s-7);
  background: var(--bg-soft);
  border: 1px solid var(--rule);
  border-radius: 10px;
}

.contact-card .row {
  display: flex;
  align-items: baseline;
  gap: var(--s-5);
  padding: var(--s-4) 0;
  border-bottom: 1px solid var(--rule);
}

.contact-card .row:last-child { border-bottom: none; padding-bottom: 0; }
.contact-card .row:first-child { padding-top: 0; }

.contact-card .label {
  flex-shrink: 0;
  min-width: 110px;
  font-size: 0.74rem;
  font-weight: 700;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--text-muted);
}

.contact-card .value {
  font-size: 1.05rem;
  color: var(--text-strong);
  line-height: 1.5;
}

.contact-card a {
  color: var(--text-strong);
  text-decoration: none;
  border-bottom: 1px solid var(--accent);
  padding-bottom: 1px;
  transition: color var(--t-fast), border-color var(--t-fast);
}

.contact-card a:hover {
  color: var(--accent-hover);
  border-color: var(--accent-hover);
}

@media (max-width: 540px) {
  .contact-card { padding: var(--s-5); }
  .contact-card .row { flex-direction: column; gap: 4px; padding: var(--s-3) 0; }
  .contact-card .label { min-width: 0; }
}

/* ============================================================
   Contact strip (homepage soft CTA)
   ============================================================ */

.contact-strip {
  padding: var(--s-8) 0;
  border-top: 1px solid var(--rule);
  border-bottom: 1px solid var(--rule);
  text-align: center;
}

.contact-strip .eyebrow {
  justify-content: center;
}

.contact-strip h2 {
  font-size: 1.45rem;
  margin: 0 auto var(--s-3);
  max-width: 560px;
}

.contact-strip p {
  color: var(--text-muted);
  max-width: 520px;
  margin: 0 auto var(--s-5);
}

.contact-strip .email-link {
  display: inline-block;
  font-size: 1.1rem;
  font-weight: 500;
  color: var(--text-strong);
  text-decoration: none;
  border-bottom: 2px solid var(--accent);
  padding-bottom: 2px;
  transition: color var(--t-fast);
}

.contact-strip .email-link:hover {
  color: var(--accent-hover);
}

/* ============================================================
   Footer
   ============================================================ */

footer.site-footer {
  background: var(--bg-soft);
  border-top: 1px solid var(--rule);
  padding: var(--s-8) 0 var(--s-6);
  margin-top: var(--s-9);
  color: var(--text-muted);
  font-size: 0.9rem;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: var(--s-7);
  margin-bottom: var(--s-7);
}

.footer-grid .brand-block svg {
  height: 44px;
  margin-bottom: var(--s-4);
}

.footer-grid .brand-block p {
  margin: 0;
  max-width: 320px;
  line-height: 1.55;
}

.footer-grid h4 {
  margin: 0 0 var(--s-3);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--text-strong);
}

.footer-grid nav, .footer-grid .links {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.footer-grid a {
  color: var(--text-muted);
  text-decoration: none;
  transition: color var(--t-fast);
  padding: 2px 0;
}

.footer-grid a:hover { color: var(--text-strong); }

.footer-legal {
  padding-top: var(--s-5);
  border-top: 1px solid var(--rule);
  font-size: 0.82rem;
  color: var(--text-faint);
  line-height: 1.5;
}

.footer-legal p { margin: 0 0 2px; }

@media (max-width: 720px) {
  .footer-grid {
    grid-template-columns: 1fr;
    gap: var(--s-6);
  }
}

/* ============================================================
   Accessibility / motion
   ============================================================ */

a:focus-visible, button:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: 2px;
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    transition: none !important;
    scroll-behavior: auto !important;
    animation: none !important;
  }
  .service:hover { transform: none; }
}

/* ============================================================
   Utility
   ============================================================ */

.mt-7 { margin-top: var(--s-7); }
.text-center { text-align: center; }