/* ============================================
   SHARED STYLES – CHS Intl
   Used by: index.html, services.html
   Design language: precision engineering,
   dark navy + cyan, sharp & structured
============================================ */

/* ============================================
   CSS VARIABLES
============================================ */
:root {
  /* Brand colours */
  --accent: #00b0d4;
  /* cyan highlight */
  --accent-dark: #0088a8;
  --accent-dim: rgba(0, 176, 212, 0.12);

  /* Surfaces */
  --bg-page: #f4f6f8;
  /* light page background */
  --bg-white: #ffffff;
  --bg-dark: #0d1b2a;
  /* deep navy – hero / dark sections */
  --bg-mid: #122030;
  /* slightly lighter navy */
  --bg-card: #ffffff;

  /* Text */
  --text-primary: #0d1b2a;
  --text-secondary: #4a5568;
  --text-muted: #7a8899;
  --text-on-dark: #e8edf2;
  --text-on-dark-muted: rgba(232, 237, 242, 0.65);

  /* Navigation */
  --nav-bg: #0d1b2a;
  --nav-text: #c8d4de;
  --nav-active: #00b0d4;

  /* Borders & dividers */
  --border: #dde3ea;
  --border-dark: rgba(255, 255, 255, 0.1);

  /* Misc */
  --shadow-sm: 0 1px 4px rgba(0, 0, 0, 0.08);
  --shadow-md: 0 4px 20px rgba(0, 0, 0, 0.12);
  --shadow-lg: 0 8px 40px rgba(0, 0, 0, 0.18);
  --radius: 2px;
  /* near-sharp corners */
  --radius-card: 4px;
}

/* ============================================
   RESET & BASE
============================================ */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 62.5%;
  scroll-behavior: smooth;
  overflow-x: hidden;
}

body {
  font-family: 'Open Sans', sans-serif;
  font-size: 1.6rem;
  line-height: 1.75;
  color: var(--text-primary);
  background: var(--bg-page);
  overflow-x: hidden;
}

::selection {
  background: var(--accent);
  color: #fff;
}

/* ============================================
   TYPOGRAPHY
============================================ */
h1,
h2,
h3,
h4,
h5,
h6 {
  font-family: 'Open Sans', sans-serif;
  font-weight: 700;
  text-rendering: optimizeLegibility;
  line-height: 1.15;
  margin-bottom: 0.5em;
  color: inherit;
}

h2 {
  font-size: 3.2rem;
  letter-spacing: -0.02em;
}

h3 {
  font-size: 2.4rem;
}

h4 {
  font-size: 2rem;
}

h5 {
  font-size: 1.7rem;
  letter-spacing: 0.01em;
}

p {
  margin: 0.8em 0;
}

a {
  color: var(--accent);
  text-decoration: none;
  transition: color .2s;
}

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

ul,
ol {
  margin: 0.8em 0 0.8em 2rem;
}

li {
  margin-bottom: 0.4em;
}

img {
  display: block;
  max-width: 100%;
  height: auto;
  border-radius: var(--radius);
}

hr {
  border: none;
  border-top: 1px solid var(--border);
  margin: 3.2rem 0;
}

blockquote {
  margin: 1.6em 0;
  padding: 1.2em 1.8em;
  border-left: 3px solid var(--accent);
  background: var(--accent-dim);
  color: var(--text-secondary);
  font-style: italic;
  border-radius: 0 var(--radius-card) var(--radius-card) 0;
}

/* ============================================
   TOP NAVIGATION BAR
============================================ */
.site-nav {
  position: sticky;
  top: 0;
  z-index: 9999;
  background: var(--nav-bg);
  border-bottom: 1px solid var(--border-dark);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 3.2rem;
  height: 5.6rem;
}

.site-nav__brand {
  display: flex;
  align-items: center;
  gap: 1rem;
  color: #fff;
  font-family: 'Open Sans', sans-serif;
  font-weight: 700;
  font-size: 1.6rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.site-nav__brand img {
  height: 2.8rem;
  width: auto;
  border-radius: 0;
  filter: brightness(0) invert(1);
}

.site-nav__brand:hover {
  color: var(--accent);
}

.site-nav__links {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  list-style: none;
  margin: 0;
  padding: 0;
}

.site-nav__links li {
  margin: 0;
}

.site-nav__links a {
  display: flex;
  align-items: center;
  height: 5.6rem;
  padding: 0 1.6rem;
  font-family: 'Open Sans', sans-serif;
  font-size: 1.35rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--nav-text);
  border-bottom: 3px solid transparent;
  transition: color .2s, border-color .2s;
}

.site-nav__links a:hover,
.site-nav__links a.active {
  color: var(--accent);
  border-bottom-color: var(--accent);
}

/* Hamburger – mobile only */
.site-nav__toggle {
  display: none;
  background: none;
  border: none;
  color: var(--nav-text);
  font-size: 2.2rem;
  cursor: pointer;
  padding: 0.4rem;
}

/* ============================================
   SECTION UTILITY CLASSES
============================================ */
.section {
  padding: 7.2rem 0;
}

.section--dark {
  background: var(--bg-dark);
  color: var(--text-on-dark);
}

.section--dark hr {
  border-color: var(--border-dark);
}

.section--dark a {
  color: var(--accent);
}

.section--dark a:hover {
  color: #fff;
}

.section--mid {
  background: var(--bg-mid);
  color: var(--text-on-dark);
}

.container {
  width: 90%;
  max-width: 1100px;
  margin: 0 auto;
}

.section-label {
  display: inline-block;
  font-size: 1.1rem;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 1.2rem;
}

.section-title {
  font-size: clamp(2.4rem, 3.5vw, 3.6rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 1.2rem;
  color: inherit;
}

.section-lead {
  font-size: 1.7rem;
  color: var(--text-secondary);
  max-width: 640px;
  line-height: 1.7;
}

.section--dark .section-lead,
.section--mid .section-lead {
  color: var(--text-on-dark-muted);
}

/* ============================================
   BUTTONS
============================================ */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.7rem;
  font-family: 'Open Sans', sans-serif;
  font-size: 1.35rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  padding: 1.1rem 2.6rem;
  border-radius: var(--radius);
  border: 2px solid transparent;
  cursor: pointer;
  transition: background .2s, color .2s, border-color .2s, transform .15s;
  text-decoration: none;
}

.btn:hover {
  transform: translateY(-1px);
}

.btn--primary {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
}

.btn--primary:hover {
  background: var(--accent-dark);
  border-color: var(--accent-dark);
  color: #fff;
}

.btn--outline {
  background: transparent;
  color: var(--accent);
  border-color: var(--accent);
}

.btn--outline:hover {
  background: var(--accent);
  color: #fff;
}

.btn--outline-light {
  background: transparent;
  color: #fff;
  border-color: rgba(255, 255, 255, 0.5);
}

.btn--outline-light:hover {
  background: rgba(255, 255, 255, 0.1);
  border-color: #fff;
  color: #fff;
}

/* ============================================
   CARD
============================================ */
.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-card);
  overflow: hidden;
  transition: box-shadow .2s, transform .2s;
}

.card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-3px);
}

.card__img {
  width: 100%;
  height: 18rem;
  object-fit: cover;
  border-radius: 0;
  display: block;
}

.card__body {
  padding: 2rem 2.2rem 2.4rem;
}

.card__tag {
  font-size: 1.05rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 0.6rem;
  display: block;
}

.card__title {
  font-size: 1.7rem;
  font-weight: 700;
  margin-bottom: 0.8rem;
  color: var(--text-primary);
}

.card__text {
  font-size: 1.45rem;
  color: var(--text-secondary);
  line-height: 1.6;
  margin: 0;
}

/* ============================================
   FOOTER
============================================ */
.site-footer {
  background: #060e17;
  color: var(--text-muted);
  padding: 3.6rem 3.2rem 2.8rem;
  font-size: 1.3rem;
}

.site-footer__inner {
  max-width: 1100px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 1.6rem;
}

.footer-icons {
  display: flex;
  gap: 1.8rem;
}

.footer-icons a {
  color: var(--text-muted);
  font-size: 1.8rem;
  transition: color .2s;
}

.footer-icons a:hover {
  color: var(--accent);
}

.footer-copy {
  color: var(--text-muted);
}

/* ============================================
   SCROLL REVEAL ANIMATION
============================================ */
.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.reveal.visible {
  opacity: 1;
  transform: none;
}

/* ============================================
   PERFORMANCE – CONTENT VISIBILITY
   Skips rendering of off-screen sections,
   improving LCP by reducing layout work.
============================================ */
.section {
  content-visibility: auto;
  contain-intrinsic-size: 0 600px;
}

/* ============================================
   RESPONSIVE
============================================ */
@media (max-width: 768px) {
  .site-nav__links {
    display: none;
  }

  .site-nav__links.open {
    display: flex;
    flex-direction: column;
    position: absolute;
    top: 5.6rem;
    left: 0;
    width: 100%;
    background: var(--nav-bg);
    border-bottom: 1px solid var(--border-dark);
    padding: 0.8rem 0 1.2rem;
    gap: 0;
  }

  .site-nav__links a {
    height: auto;
    padding: 1.2rem 2.4rem;
    border-bottom: none;
    border-left: 3px solid transparent;
  }

  .site-nav__links a:hover,
  .site-nav__links a.active {
    border-bottom: none;
    border-left-color: var(--accent);
  }

  .site-nav__toggle {
    display: block;
  }

  .site-nav {
    position: sticky;
  }
}

@media (min-width: 1024px) {
  body {
    font-size: 1.65rem;
  }
}