/* ==========================================================================
   Components — Buttons, Cards, Tables, Header, Footer, Nav
   ========================================================================== */

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-xs);
  padding: 12px 28px;
  font-family: var(--font-body);
  font-size: var(--text-base);
  font-weight: 500;
  line-height: 1;
  border-radius: var(--radius-btn);
  transition: background-color var(--transition-fast),
              color var(--transition-fast),
              border-color var(--transition-fast),
              transform var(--transition-fast),
              box-shadow var(--transition-fast);
  cursor: pointer;
  text-decoration: none;
  white-space: nowrap;
}

.btn--primary {
  background-color: var(--teal);
  color: var(--white);
  border: 1.5px solid var(--teal);
}

.btn--primary:hover {
  background-color: var(--teal-dark);
  border-color: var(--teal-dark);
  color: var(--white);
  transform: translateY(-1px);
}

.btn--secondary {
  background-color: transparent;
  color: var(--navy);
  border: 1.5px solid var(--navy);
}

.btn--secondary:hover {
  background-color: var(--navy);
  color: var(--white);
  transform: translateY(-1px);
}

/* On dark backgrounds */
.section--dark .btn--secondary,
.section--deep .btn--secondary {
  color: var(--white);
  border-color: var(--white);
}

.section--dark .btn--secondary:hover,
.section--deep .btn--secondary:hover {
  background-color: var(--white);
  color: var(--navy);
}

/* Spec links on dark backgrounds */
.section--dark .spec-link,
.section--deep .spec-link {
  color: var(--white);
}

.section--dark .spec-link:hover,
.section--deep .spec-link:hover {
  color: rgba(255, 255, 255, 0.8);
}

.btn--sm {
  padding: 8px 20px;
  font-size: var(--text-sm);
}

/* ---------- Cards ---------- */
.card {
  background-color: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius-card);
  padding: var(--space-lg);
  transition: box-shadow var(--transition-base),
              transform var(--transition-base);
}

.card:hover {
  box-shadow: 0 8px 24px rgba(15, 43, 76, 0.08);
  transform: translateY(-2px);
}

.card__icon {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-card);
  background-color: var(--surface);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: var(--space-sm);
  color: var(--teal);
}

.card__icon svg {
  width: 24px;
  height: 24px;
}

.card__title {
  font-family: var(--font-heading);
  font-size: var(--text-subsection);
  font-weight: 600;
  color: var(--navy);
  margin-bottom: var(--space-xs);
  line-height: var(--lh-subsection);
}

.card__text {
  color: var(--slate);
  font-size: var(--text-base);
  line-height: var(--lh-body);
}

/* ---------- Spec Link ---------- */
.spec-link {
  display: inline-flex;
  align-items: center;
  gap: var(--space-xxs);
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--teal);
  margin-top: var(--space-sm);
  transition: color var(--transition-fast), gap var(--transition-fast);
}

.spec-link:hover {
  color: var(--teal-dark);
  gap: var(--space-xs);
}

.spec-link svg {
  width: 16px;
  height: 16px;
  flex-shrink: 0;
}

/* ---------- Tables ---------- */
.table-wrap {
  overflow-x: auto;
  border-radius: var(--radius-card);
  border: 1px solid var(--border);
}

table {
  width: 100%;
  border-collapse: collapse;
  font-size: var(--text-sm);
}

thead th {
  background-color: var(--navy);
  color: var(--white);
  font-family: var(--font-heading);
  font-weight: 600;
  text-align: left;
  padding: 12px 16px;
  border-bottom: 2px solid var(--teal);
}

tbody td {
  padding: 12px 16px;
  border-bottom: 1px solid var(--border);
}

tbody tr:nth-child(even) {
  background-color: var(--surface);
}

tbody tr:nth-child(odd) {
  background-color: var(--white);
}

/* ---------- Header ---------- */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  height: var(--header-height);
  background-color: var(--white);
  transition: background-color var(--transition-base),
              box-shadow var(--transition-base);
}

.site-header.scrolled {
  box-shadow: 0 1px 4px rgba(15, 43, 76, 0.06);
}

.header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--header-height);
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-md);
}

/* Logo */
.header__logo {
  font-family: var(--font-heading);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--navy);
  letter-spacing: 0.05em;
  text-decoration: none;
  flex-shrink: 0;
}

.header__logo:hover {
  color: var(--navy);
}

/* Nav */
.header__nav {
  display: flex;
  align-items: center;
  gap: var(--space-lg);
}

.nav__list {
  display: flex;
  align-items: center;
  gap: var(--space-md);
}

.nav__link {
  font-family: var(--font-body);
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--slate);
  text-decoration: none;
  padding: var(--space-xs) 0;
  position: relative;
  transition: color var(--transition-fast);
}

.nav__link:hover,
.nav__link--active {
  color: var(--teal);
}

.nav__link--active::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  height: 2px;
  background-color: var(--teal);
  border-radius: 1px;
}

/* Dropdown */
.nav__item--dropdown {
  position: relative;
}

.nav__dropdown-toggle {
  display: inline-flex;
  align-items: center;
  gap: 4px;
}

.nav__dropdown-toggle svg {
  width: 14px;
  height: 14px;
  transition: transform var(--transition-fast);
}

.nav__item--dropdown:hover .nav__dropdown-toggle svg {
  transform: rotate(180deg);
}

.nav__dropdown {
  position: absolute;
  top: 100%;
  left: 0;
  min-width: 220px;
  background-color: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius-card);
  box-shadow: 0 4px 12px rgba(15, 43, 76, 0.08);
  padding: var(--space-xs) 0;
  opacity: 0;
  visibility: hidden;
  transform: translateY(8px);
  transition: opacity var(--transition-fast),
              transform var(--transition-fast),
              visibility var(--transition-fast);
  pointer-events: none;
}

.nav__item--dropdown:hover .nav__dropdown {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
  pointer-events: auto;
}

.nav__dropdown a {
  display: block;
  padding: 10px var(--space-sm);
  font-size: var(--text-sm);
  font-weight: 400;
  color: var(--slate);
  transition: background-color var(--transition-fast),
              color var(--transition-fast);
}

.nav__dropdown a:hover {
  background-color: var(--surface);
  color: var(--teal);
}

/* Header CTA */
.header__cta {
  margin-left: var(--space-sm);
}

/* Mobile toggle */
.header__toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  width: 28px;
  padding: 4px 0;
  cursor: pointer;
  background: none;
  border: none;
}

.header__toggle span {
  display: block;
  height: 2px;
  background-color: var(--navy);
  border-radius: 1px;
  transition: transform var(--transition-base),
              opacity var(--transition-base);
}

.header__toggle.active span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.header__toggle.active span:nth-child(2) {
  opacity: 0;
}

.header__toggle.active span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* Mobile menu */
.mobile-menu {
  display: none;
  position: fixed;
  top: var(--header-height);
  left: 0;
  right: 0;
  bottom: 0;
  background-color: var(--white);
  padding: var(--space-md);
  overflow-y: auto;
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--transition-base),
              visibility var(--transition-base);
}

.mobile-menu.open {
  opacity: 1;
  visibility: visible;
}

.mobile-menu__list {
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
}

.mobile-menu__link {
  display: block;
  padding: 12px 0;
  font-size: var(--text-lg);
  font-weight: 500;
  color: var(--navy);
  border-bottom: 1px solid var(--border);
  text-decoration: none;
  transition: color var(--transition-fast);
}

.mobile-menu__link:hover {
  color: var(--teal);
}

.mobile-menu__sub {
  padding-left: var(--space-md);
}

.mobile-menu__sub a {
  display: block;
  padding: 10px 0;
  font-size: var(--text-base);
  color: var(--slate);
  text-decoration: none;
  transition: color var(--transition-fast);
}

.mobile-menu__sub a:hover {
  color: var(--teal);
}

.mobile-menu__cta {
  margin-top: var(--space-lg);
}

.mobile-menu__cta .btn {
  width: 100%;
  text-align: center;
}

/* ---------- Footer ---------- */
.site-footer {
  background-color: var(--deep);
  color: var(--deep-text);
  padding-top: var(--space-2xl);
  padding-bottom: 0;
}

.footer__grid {
  display: grid;
  grid-template-columns: 1.5fr 1fr 1.5fr 1.5fr;
  gap: var(--space-xl);
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-md);
}

.footer__logo {
  font-family: var(--font-heading);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--white);
  letter-spacing: 0.05em;
  margin-bottom: var(--space-sm);
}

.footer__tagline {
  font-size: var(--text-sm);
  color: var(--slate-light);
  line-height: var(--lh-body);
}

.footer__heading {
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--white);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-bottom: var(--space-sm);
}

.footer__links {
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
}

.footer__links a {
  font-size: var(--text-sm);
  color: var(--slate-light);
  text-decoration: none;
  transition: color var(--transition-fast);
}

.footer__links a:hover {
  color: var(--white);
}

.footer__contact-item {
  font-size: var(--text-sm);
  color: var(--slate-light);
  margin-bottom: var(--space-xs);
  line-height: var(--lh-body);
}

.footer__contact-item a {
  color: var(--slate-light);
  text-decoration: none;
  transition: color var(--transition-fast);
}

.footer__contact-item a:hover {
  color: var(--white);
}

.footer__bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: var(--space-md);
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  font-size: var(--text-micro);
  color: var(--slate-light);
}

.footer__disclaimer-line {
  max-width: var(--max-width);
  margin: var(--space-xl) auto 0;
  padding: 0 var(--space-md) 14px;
  text-align: center;
  font-size: var(--text-micro);
  color: var(--slate-light);
  line-height: var(--lh-body);
}

/* Footer responsive */
@media (max-width: 768px) {
  .footer__grid {
    grid-template-columns: 1fr;
    gap: var(--space-lg);
  }

  .footer__bar {
    flex-direction: column;
    gap: var(--space-xs);
    text-align: center;
  }
}

/* ---------- Mobile Nav ---------- */
@media (max-width: 768px) {
  .header__nav {
    display: none;
  }

  .header__toggle {
    display: flex;
  }

  .mobile-menu {
    display: block;
  }

  .site-header.scrolled {
    background-color: var(--white) !important;
  }
}

/* ---------- Scroll Reveal Animations ---------- */
.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 600ms ease-out, transform 600ms ease-out;
}

.reveal.revealed {
  opacity: 1;
  transform: translateY(0);
}

/* Staggered children */
.reveal-stagger > .reveal:nth-child(1) { transition-delay: 0ms; }
.reveal-stagger > .reveal:nth-child(2) { transition-delay: 120ms; }
.reveal-stagger > .reveal:nth-child(3) { transition-delay: 240ms; }
.reveal-stagger > .reveal:nth-child(4) { transition-delay: 360ms; }

/* Respect reduced motion */
@media (prefers-reduced-motion: reduce) {
  .reveal {
    opacity: 1;
    transform: none;
    transition: none;
  }
}

/* ---------- SVG Illustrations ---------- */
.svg-illustration {
  width: 100%;
  height: auto;
  display: block;
}

.svg-illustration--tower {
  max-width: 460px;
}

.svg-illustration--tower-sm {
  max-width: 320px;
}

.svg-illustration--airflow {
  max-width: 100%;
  margin: 0 auto;
}

.svg-illustration--filtration {
  max-width: 100%;
  margin: 0 auto;
}

@media (max-width: 768px) {
  .svg-illustration--tower {
    max-width: 280px;
    margin: 0 auto;
  }

  .svg-illustration--tower-sm {
    max-width: 220px;
    margin: 0 auto;
  }
}