/* ==========================================================================
   main.css — RDS Website Global Styles
   ========================================================================== */

/* --------------------------------------------------------------------------
   1. CSS Custom Properties
   -------------------------------------------------------------------------- */
:root {
  --color-bg:            #0d0d0d;
  --color-surface:       #161616;
  --color-surface-2:     #1e1e1e;
  --color-accent:        #00b4d8;
  --color-accent-light:  #48cae4;
  --color-accent-dark:   #0077b6;
  --color-text:          #f0f0f0;
  --color-text-muted:    #a0a0a0;
  --color-on-accent:     #0d0d0d;
  --color-border:        #2a2a2a;
  --color-danger:        #e63946;

  --font-stack:          'Segoe UI', 'Helvetica Neue', Arial, sans-serif;

  --nav-height:          72px;
  --content-max-width:   1200px;
  --section-pad-v:       80px;
  --section-pad-v-sm:    48px;
  --radius-sm:           4px;
  --radius-md:           8px;
  --radius-lg:           16px;
  --transition-speed:    0.25s;

  --shadow-card:         0 4px 24px rgba(0, 0, 0, 0.4);
  --shadow-glow:         0 0 24px rgba(0, 180, 216, 0.25);
}

/* --------------------------------------------------------------------------
   2. Reset & Base
   -------------------------------------------------------------------------- */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  background-color: var(--color-bg);
  color: var(--color-text);
  font-family: var(--font-stack);
  line-height: 1.7;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  -webkit-font-smoothing: antialiased;
}

main {
  flex: 1;
}

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

a {
  color: var(--color-accent);
  text-decoration: none;
  transition: color var(--transition-speed) ease,
              opacity var(--transition-speed) ease;
}

a:hover,
a:focus {
  color: var(--color-accent-light);
  text-decoration: underline;
}

h1, h2, h3, h4, h5, h6 {
  line-height: 1.25;
  color: var(--color-text);
  font-weight: 700;
}

h1 { font-size: clamp(2rem,   5vw, 3.5rem); }
h2 { font-size: clamp(1.5rem, 3vw, 2.5rem); }
h3 { font-size: clamp(1.2rem, 2vw, 1.6rem); }

p {
  color: var(--color-text-muted);
  margin-bottom: 1rem;
}

p:last-child {
  margin-bottom: 0;
}

ul, ol {
  padding-left: 1.5rem;
}

li {
  color: var(--color-text-muted);
  margin-bottom: 0.4rem;
}

address {
  font-style: normal;
}

/* --------------------------------------------------------------------------
   3. Accessibility
   -------------------------------------------------------------------------- */
.skip-link {
  position: absolute;
  top: -100px;
  left: 1rem;
  background: var(--color-accent);
  color: var(--color-on-accent);
  padding: 0.5rem 1rem;
  border-radius: var(--radius-sm);
  font-weight: 700;
  z-index: 9999;
  transition: top 0.2s;
}

.skip-link:focus {
  top: 1rem;
  text-decoration: none;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* Focus rings */
:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 3px;
}

/* --------------------------------------------------------------------------
   4. Layout Utilities
   -------------------------------------------------------------------------- */
.content-container {
  max-width: var(--content-max-width);
  margin-inline: auto;
  padding-inline: clamp(1rem, 4vw, 2rem);
}

.section-padded {
  padding-block: var(--section-pad-v);
}

.section-dark {
  background-color: var(--color-surface);
}

.two-col {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3rem;
  align-items: start;
}

.two-col--reverse .two-col-text {
  order: 2;
}
.two-col--reverse .two-col-visual {
  order: 1;
}

.section-header {
  margin-bottom: 3rem;
}

.section-header h2 {
  margin-bottom: 0.75rem;
}

.section-header-centered {
  text-align: center;
  margin-bottom: 2.5rem;
}

.section-subtitle {
  font-size: 1.1rem;
  max-width: 65ch;
}

/* --------------------------------------------------------------------------
   5. Buttons
   -------------------------------------------------------------------------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.75rem 1.75rem;
  border-radius: var(--radius-sm);
  font-weight: 600;
  font-size: 0.95rem;
  cursor: pointer;
  border: 2px solid transparent;
  transition:
    background-color var(--transition-speed) ease,
    border-color     var(--transition-speed) ease,
    color            var(--transition-speed) ease,
    box-shadow       var(--transition-speed) ease;
  text-decoration: none !important;
  line-height: 1;
  white-space: nowrap;
}

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

.btn-primary:hover,
.btn-primary:focus {
  background-color: var(--color-accent-light);
  border-color:     var(--color-accent-light);
  color:            var(--color-on-accent);
  box-shadow:       var(--shadow-glow);
}

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

.btn-outline:hover,
.btn-outline:focus {
  background-color: var(--color-accent);
  color:            var(--color-on-accent);
}

.btn-sm {
  padding: 0.5rem 1.25rem;
  font-size: 0.875rem;
}

.btn-lg {
  padding: 1rem 2.5rem;
  font-size: 1.05rem;
}

/* --------------------------------------------------------------------------
   6. Navigation
   -------------------------------------------------------------------------- */
[role="banner"] {
  position: sticky;
  top: 0;
  z-index: 1000;
  background-color: rgba(13, 13, 13, 0.95);
  border-bottom: 1px solid var(--color-border);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
}

.nav-container {
  max-width: var(--content-max-width);
  margin-inline: auto;
  padding-inline: clamp(1rem, 4vw, 2rem);
  height: var(--nav-height);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 2rem;
}

.nav-logo {
  display: flex;
  align-items: center;
  flex-shrink: 0;
  text-decoration: none !important;
}

.nav-logo img {
  height: 48px;
  width: auto;
}

.nav-list {
  display: flex;
  list-style: none;
  gap: 0.25rem;
  padding-left: 0;
  margin: 0;
}

.nav-list li {
  margin-bottom: 0;
  color: inherit;
}

.nav-link {
  display: block;
  padding: 0.5rem 0.875rem;
  color: var(--color-text-muted);
  font-weight: 500;
  font-size: 0.925rem;
  border-radius: var(--radius-sm);
  transition: color var(--transition-speed) ease,
              background-color var(--transition-speed) ease;
  text-decoration: none !important;
}

.nav-link:hover,
.nav-link:focus {
  color: var(--color-text);
  background-color: var(--color-surface-2);
}

.nav-link.active {
  color: var(--color-accent);
  font-weight: 700;
}

/* Hamburger */
.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.5rem;
  border-radius: var(--radius-sm);
}

.hamburger-line {
  display: block;
  width: 24px;
  height: 2px;
  background-color: var(--color-text);
  transition: transform var(--transition-speed) ease,
              opacity   var(--transition-speed) ease;
}

.nav-toggle[aria-expanded="true"] .hamburger-line:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.nav-toggle[aria-expanded="true"] .hamburger-line:nth-child(2) {
  opacity: 0;
}

.nav-toggle[aria-expanded="true"] .hamburger-line:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* --------------------------------------------------------------------------
   7. Footer
   -------------------------------------------------------------------------- */
[role="contentinfo"] {
  background-color: var(--color-surface);
  border-top: 1px solid var(--color-border);
  padding-top: 3rem;
}

.footer-container {
  max-width: var(--content-max-width);
  margin-inline: auto;
  padding-inline: clamp(1rem, 4vw, 2rem);
  display: grid;
  grid-template-columns: 2fr 1fr 1.5fr;
  gap: 3rem;
  padding-bottom: 2.5rem;
}

.footer-tagline {
  color: var(--color-text-muted);
  font-size: 0.875rem;
  margin-top: 0.75rem;
}

.footer-heading {
  font-size: 0.8rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--color-accent);
  margin-bottom: 1rem;
}

.footer-nav-list {
  list-style: none;
  padding-left: 0;
}

.footer-nav-list li {
  margin-bottom: 0.5rem;
}

.footer-nav-list a {
  color: var(--color-text-muted);
  font-size: 0.9rem;
}

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

.footer-contact address {
  font-style: normal;
}

.footer-contact p {
  font-size: 0.9rem;
  margin-bottom: 0.5rem;
}

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

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

.footer-bottom {
  border-top: 1px solid var(--color-border);
  padding-block: 1.25rem;
  text-align: center;
}

.footer-bottom p {
  font-size: 0.8rem;
  color: var(--color-text-muted);
  margin-bottom: 0.25rem;
}

.footer-disclaimer {
  font-size: 0.75rem !important;
  opacity: 0.6;
}

/* --------------------------------------------------------------------------
   8. Page Hero (interior pages)
   -------------------------------------------------------------------------- */
.page-hero {
  background: linear-gradient(
    135deg,
    var(--color-surface) 0%,
    var(--color-bg) 100%
  );
  border-bottom: 1px solid var(--color-border);
  padding-block: clamp(3rem, 8vw, 5rem);
  position: relative;
  overflow: hidden;
}

.page-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background: radial-gradient(
    ellipse 60% 80% at 80% 50%,
    rgba(0, 180, 216, 0.06) 0%,
    transparent 70%
  );
  pointer-events: none;
}

.page-hero-content {
  position: relative;
  z-index: 1;
  max-width: 75ch;
}

.page-hero-content h1 {
  margin-bottom: 1rem;
}

.page-hero-subtitle {
  font-size: clamp(1rem, 2vw, 1.25rem);
  color: var(--color-text-muted);
  max-width: 65ch;
  margin-bottom: 0;
}

/* --------------------------------------------------------------------------
   9. CTA Banner
   -------------------------------------------------------------------------- */
.cta-banner {
  background: linear-gradient(
    135deg,
    var(--color-accent-dark) 0%,
    var(--color-accent) 100%
  );
}

.cta-content {
  text-align: center;
}

.cta-content h2 {
  color: #ffffff;
  margin-bottom: 1rem;
}

.cta-content p {
  color: rgba(255,255,255,0.85);
  font-size: 1.1rem;
  margin-bottom: 2rem;
}

.cta-content .btn-primary {
  background-color: #ffffff;
  border-color: #ffffff;
  color: var(--color-accent-dark);
}

.cta-content .btn-primary:hover {
  background-color: rgba(255,255,255,0.9);
  box-shadow: 0 4px 20px rgba(0,0,0,0.2);
}

/* --------------------------------------------------------------------------
   10. Product Comparison Table
   -------------------------------------------------------------------------- */
.table-wrapper {
  overflow-x: auto;
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border);
}

.comparison-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9rem;
}

.comparison-table th,
.comparison-table td {
  padding: 0.875rem 1.25rem;
  border-bottom: 1px solid var(--color-border);
  text-align: left;
  vertical-align: top;
}

.comparison-table th {
  background-color: var(--color-surface);
  color: var(--color-accent);
  font-weight: 700;
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.comparison-table td {
  color: var(--color-text-muted);
}

.comparison-table td:first-child {
  color: var(--color-text);
  font-weight: 600;
  min-width: 150px;
}

.comparison-table tr:last-child td {
  border-bottom: none;
}

.comparison-table tr:nth-child(even) td {
  background-color: rgba(255,255,255,0.02);
}

/* --------------------------------------------------------------------------
   11. Spec List
   -------------------------------------------------------------------------- */
.spec-list {
  list-style: none;
  padding-left: 0;
  margin-bottom: 2rem;
}

.spec-list li {
  display: grid;
  grid-template-columns: 170px 1fr;
  gap: 1rem;
  padding-block: 0.6rem;
  border-bottom: 1px solid var(--color-border);
  margin-bottom: 0;
  color: var(--color-text-muted);
}

.spec-label {
  color: var(--color-text);
  font-weight: 600;
  font-size: 0.875rem;
}

.spec-value {
  font-size: 0.875rem;
}

/* --------------------------------------------------------------------------
   12. Responsive
   -------------------------------------------------------------------------- */
@media (max-width: 900px) {
  .two-col {
    grid-template-columns: 1fr;
  }
  .two-col--reverse .two-col-text,
  .two-col--reverse .two-col-visual {
    order: unset;
  }
  .footer-container {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 640px) {
  :root {
    --section-pad-v: var(--section-pad-v-sm);
  }

  .nav-toggle {
    display: flex;
  }

  #primary-nav {
    display: none;
    position: absolute;
    top: var(--nav-height);
    left: 0;
    right: 0;
    background-color: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
    padding: 1rem;
  }

  #primary-nav.is-open {
    display: block;
  }

  .nav-list {
    flex-direction: column;
    gap: 0;
  }

  .nav-link {
    padding: 0.75rem 1rem;
    font-size: 1rem;
  }

  .footer-container {
    grid-template-columns: 1fr;
    gap: 2rem;
  }

  .spec-list li {
    grid-template-columns: 1fr;
    gap: 0.25rem;
  }
}