/* Helix — corporate site
   v1 build · May 2026
   Brand palette: #D6D6D6 / #8C8C8C / #444545 / #000000 (monochrome) */

:root {
  --paper:   #ffffff;
  --paper-soft: #f6f6f7;
  --paper-grey: #ececee;
  --grey-100: #D6D6D6;
  --grey-300: #b2b2b4;
  --grey-500: #8C8C8C;
  --grey-700: #5a5b5d;
  --grey-800: #444545;
  --grey-900: #2a2b2c;
  --ink:      #1a1b1c;
  --ink-soft: #555659;
  --black:    #000000;
  --hairline: #e3e3e6;

  /* Accent — a controlled deep-purple borrowed from Sherpa's palette,
     used sparingly so Helix stays monochrome but has a single
     family-resemblance moment with the product brands */
  --accent: #5b4f7a;
  --accent-deep: #423a5a;

  --r-sm: 6px;
  --r-md: 14px;
  --r-lg: 22px;
  --shadow-card: 0 1px 2px rgba(0,0,0,0.04), 0 12px 32px rgba(0,0,0,0.06);
  --shadow-deep: 0 4px 8px rgba(0,0,0,0.08), 0 24px 64px rgba(0,0,0,0.14);

  --max: 1200px;
  --gutter: clamp(20px, 4vw, 44px);
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  font-size: 16px;
  line-height: 1.55;
  color: var(--ink);
  background: var(--paper);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
img, svg { display: block; max-width: 100%; height: auto; }
a { color: var(--ink); text-decoration: none; }
a:hover { color: var(--black); }
hr { border: 0; border-top: 1px solid var(--hairline); margin: 0; }

/* Type */
h1, h2, h3, h4 {
  font-family: 'Inter', sans-serif;
  font-weight: 600;
  letter-spacing: -0.024em;
  color: var(--ink);
  margin: 0 0 .5em;
}
h1 { font-size: clamp(2.4rem, 5.6vw, 4rem); line-height: 1.04; letter-spacing: -0.034em; }
h2 { font-size: clamp(1.7rem, 3vw, 2.4rem); line-height: 1.12; }
h3 { font-size: 1.18rem; line-height: 1.3; }
p { margin: 0 0 1em; color: var(--ink-soft); }
.eyebrow {
  font-size: 0.76rem;
  font-weight: 600;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--grey-700);
  margin: 0 0 .9em;
}
.eyebrow--dark { color: var(--grey-300); }
.lead { font-size: 1.18rem; color: var(--ink-soft); }

/* Layout */
.wrap { max-width: var(--max); margin: 0 auto; padding: 0 var(--gutter); }
.section { padding: clamp(80px, 10vw, 140px) 0; }
.section--tight { padding: clamp(56px, 7vw, 96px) 0; }
.section--dark { background: var(--black); color: #d5d5d8; }
.section--dark h1, .section--dark h2, .section--dark h3 { color: #fff; }
.section--dark p { color: #a8a9ad; }
.section--dark .eyebrow { color: var(--grey-300); }
.section--soft { background: var(--paper-soft); }
.section--grey { background: var(--paper-grey); }

/* Nav */
.nav {
  position: sticky; top: 0; z-index: 50;
  background: rgba(255,255,255,0.88);
  backdrop-filter: saturate(140%) blur(12px);
  -webkit-backdrop-filter: saturate(140%) blur(12px);
  border-bottom: 1px solid var(--hairline);
}
.nav__inner {
  display: flex; align-items: center; justify-content: space-between;
  padding: 16px var(--gutter);
  max-width: var(--max); margin: 0 auto;
}
.nav__logo { height: 26px; width: auto; }
.nav__links { display: flex; gap: 30px; align-items: center; }
.nav__links a {
  color: var(--grey-700); font-size: 0.92rem; font-weight: 500;
}
.nav__links a:hover { color: var(--black); }
.nav__cta {
  background: var(--black); color: #fff !important;
  padding: 9px 18px; border-radius: var(--r-sm);
  font-size: 0.88rem; font-weight: 600;
}
.nav__cta:hover { background: var(--grey-800); }
@media (max-width: 720px) {
  .nav__links .nav__hide-sm { display: none; }
  .nav__links { gap: 16px; }
}

/* Hero — CINEMATIC photo */
.hero {
  position: relative;
  min-height: 88vh;
  display: flex; align-items: center;
  color: #fff;
  overflow: hidden;
  background: var(--black);
}
.hero__bg {
  position: absolute; inset: 0;
  background-image: url('../img/hero.jpg');
  background-size: cover;
  background-position: center 38%;
  /* Force monochrome to keep Helix on-brand */
  filter: grayscale(85%) contrast(1.06) brightness(0.62);
  transform: scale(1.04);
}
.hero__bg::after {
  content: '';
  position: absolute; inset: 0;
  background:
    linear-gradient(180deg, rgba(0,0,0,0.55) 0%, rgba(0,0,0,0.25) 35%, rgba(0,0,0,0.78) 100%),
    radial-gradient(ellipse at 20% 70%, rgba(91,79,122,0.25) 0%, transparent 60%);
}
.hero__inner {
  position: relative; z-index: 1;
  padding: clamp(80px, 12vw, 160px) 0 clamp(60px, 10vw, 140px);
  max-width: var(--max); margin: 0 auto;
  padding-left: var(--gutter); padding-right: var(--gutter);
  width: 100%;
}
.hero h1 { color: #fff; max-width: 14em; }
.hero__sub {
  font-size: 1.22rem; color: rgba(255,255,255,0.82);
  margin: 24px 0 36px; max-width: 36em;
}
.hero__micro {
  font-size: 0.95rem; color: rgba(255,255,255,0.62);
  margin-bottom: 38px; max-width: 36em;
}
.hero__cta { display: flex; gap: 12px; flex-wrap: wrap; }

/* Buttons */
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 14px 24px; border-radius: var(--r-sm);
  font-weight: 600; font-size: 0.96rem;
  border: 1px solid transparent;
  cursor: pointer; transition: transform .12s ease, background .12s ease, border-color .12s ease, color .12s ease;
}
.btn:hover { transform: translateY(-1px); }
.btn--primary { background: #fff; color: var(--black); }
.btn--primary:hover { background: var(--grey-100); color: var(--black); }
.btn--dark { background: var(--black); color: #fff; }
.btn--dark:hover { background: var(--grey-800); color: #fff; }
.btn--ghost-on-dark { background: transparent; color: #fff; border-color: rgba(255,255,255,0.4); }
.btn--ghost-on-dark:hover { border-color: #fff; }
.btn--ghost { background: transparent; color: var(--ink); border-color: var(--hairline); }
.btn--ghost:hover { border-color: var(--black); color: var(--black); }

/* Two-col */
.two-col {
  display: grid; gap: 56px;
  grid-template-columns: 1fr 1fr;
  align-items: center;
}
@media (max-width: 880px) { .two-col { grid-template-columns: 1fr; gap: 36px; } }

/* Product cards (large) */
.products {
  display: grid; gap: 22px;
  grid-template-columns: 1fr 1fr;
}
@media (max-width: 820px) { .products { grid-template-columns: 1fr; } }
.product-card {
  position: relative;
  border-radius: var(--r-lg);
  padding: 44px 40px;
  min-height: 360px;
  color: #fff;
  overflow: hidden;
  display: flex; flex-direction: column; justify-content: space-between;
  text-decoration: none;
  transition: transform .2s ease, box-shadow .2s ease;
  box-shadow: var(--shadow-card);
}
.product-card:hover { transform: translateY(-3px); box-shadow: var(--shadow-deep); }
.product-card__logo { height: 28px; width: auto; margin-bottom: 24px; }
.product-card__title { font-size: 1.6rem; color: #fff; margin: 0 0 10px; letter-spacing: -0.02em; }
.product-card__body { color: rgba(255,255,255,0.82); font-size: 0.98rem; margin: 0; max-width: 28em; }
.product-card__cta {
  display: inline-flex; align-items: center; gap: 8px;
  margin-top: 24px;
  color: #fff; font-weight: 600; font-size: 0.92rem;
}
.product-card--sherpa {
  background:
    radial-gradient(circle at 20% 20%, rgba(255,255,255,0.12), transparent 55%),
    linear-gradient(135deg, #774385 0%, #625684 55%, #303C40 100%);
}
.product-card--zend {
  background:
    radial-gradient(circle at 80% 20%, rgba(255,255,255,0.12), transparent 55%),
    linear-gradient(135deg, #F2B97D 0%, #EA532A 50%, #C4321F 100%);
}

/* Principle/approach cards */
.principles { display: grid; gap: 22px; grid-template-columns: repeat(3, 1fr); }
@media (max-width: 860px) { .principles { grid-template-columns: 1fr; } }
.principle {
  background: #fff;
  border: 1px solid var(--hairline);
  border-radius: var(--r-md);
  padding: 30px 28px;
  box-shadow: var(--shadow-card);
}
.principle__num {
  font-size: 0.82rem; font-weight: 700;
  letter-spacing: 0.16em; color: var(--grey-500);
  margin-bottom: 14px;
}
.principle h3 { margin-bottom: 8px; }
.principle p { margin: 0; font-size: 0.96rem; }

/* Bullets */
.bullets { list-style: none; padding: 0; margin: 24px 0 0; }
.bullets li {
  display: flex; gap: 12px;
  padding: 14px 0;
  border-bottom: 1px solid var(--hairline);
  font-size: 0.98rem;
  color: var(--ink-soft);
}
.bullets li:last-child { border-bottom: 0; }
.bullets li::before {
  content: ''; flex: none;
  width: 18px; height: 18px; margin-top: 3px;
  background: var(--black);
  -webkit-mask: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24'><path d='M5 12h14M13 6l6 6-6 6' stroke='black' stroke-width='2' fill='none' stroke-linecap='round' stroke-linejoin='round'/></svg>") center/contain no-repeat;
          mask: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24'><path d='M5 12h14M13 6l6 6-6 6' stroke='black' stroke-width='2' fill='none' stroke-linecap='round' stroke-linejoin='round'/></svg>") center/contain no-repeat;
}

/* CTA strip — typographic */
.cta-strip {
  background: linear-gradient(120deg, var(--black) 0%, var(--grey-800) 100%);
  color: #fff;
  border-radius: var(--r-lg);
  padding: clamp(40px, 6vw, 72px);
  display: flex; gap: 32px; flex-wrap: wrap;
  align-items: center; justify-content: space-between;
  box-shadow: var(--shadow-deep);
}
.cta-strip h2 { color: #fff; margin: 0; max-width: 22em; letter-spacing: -0.022em; }
.cta-strip p { color: rgba(255,255,255,0.74); margin: 10px 0 0; max-width: 36em; }

/* Mid-band typographic */
.midband {
  background: linear-gradient(140deg, #1a1b1c 0%, #2a2b2c 50%, #444545 100%);
  color: #fff;
  border-radius: var(--r-lg);
  padding: clamp(56px, 8vw, 96px) clamp(40px, 6vw, 80px);
  text-align: center;
  position: relative;
  overflow: hidden;
}
.midband::after {
  content: '';
  position: absolute; inset: 0;
  background:
    repeating-linear-gradient(45deg, transparent 0 16px, rgba(255,255,255,0.025) 16px 17px);
  pointer-events: none;
}
.midband h2 {
  font-size: clamp(1.8rem, 4vw, 3rem); color: #fff;
  margin: 0 auto 14px; max-width: 22em;
  letter-spacing: -0.024em;
}
.midband p { color: rgba(255,255,255,0.74); max-width: 38em; margin: 0 auto; }

/* Footer */
.footer {
  background: #0c0c0d;
  color: #9a9b9e;
  padding: 64px 0 30px;
}
.footer__top {
  display: grid; gap: 36px;
  grid-template-columns: 1.6fr 1fr 1fr 1fr;
}
@media (max-width: 820px) { .footer__top { grid-template-columns: 1fr 1fr; } }
@media (max-width: 520px) { .footer__top { grid-template-columns: 1fr; } }
.footer h4 {
  color: #fff; font-size: 0.78rem;
  letter-spacing: 0.14em; text-transform: uppercase;
  margin: 0 0 14px;
}
.footer a { color: #b2b3b6; }
.footer a:hover { color: #fff; }
.footer ul { list-style: none; padding: 0; margin: 0; display: grid; gap: 8px; font-size: 0.92rem; }
.footer__brand-line { display: flex; align-items: center; gap: 16px; margin: 0 0 14px; }
.footer__brand-line img { height: 22px; }
.footer__products {
  display: flex; gap: 22px; align-items: center;
  margin-top: 16px; flex-wrap: wrap;
}
.footer__products img { height: 18px; opacity: 0.85; }
.footer__products img:hover { opacity: 1; }
.footer__bottom {
  margin-top: 48px; padding-top: 22px;
  border-top: 1px solid rgba(255,255,255,0.08);
  display: flex; justify-content: space-between; gap: 16px; flex-wrap: wrap;
  font-size: 0.84rem; color: #6f7073;
}

/* Doc body (privacy/terms) */
.doc { max-width: 780px; }
.doc h1 { font-size: 2rem; }
.doc h2 { font-size: 1.3rem; margin-top: 2em; }
.doc p, .doc li { font-size: 0.98rem; line-height: 1.65; }
.doc__meta {
  font-size: 0.86rem; color: var(--ink-soft);
  padding: 12px 16px; background: var(--paper-soft);
  border-left: 3px solid var(--black);
  border-radius: 0 var(--r-sm) var(--r-sm) 0;
  margin: 0 0 28px;
}

/* Utility */
.center { text-align: center; }
.muted { color: var(--ink-soft); }
.mt-0 { margin-top: 0; }
.mb-0 { margin-bottom: 0; }
.spacer-md { height: 32px; }
.spacer-lg { height: 56px; }