/* ============================================
   ThermOS — Layout
   Header, footer, grid systems, navigation
   ============================================ */

/* ============================================
   HEADER
   ============================================ */

.header {
  position: sticky;
  top: 0;
  left: 0;
  right: 0;
  z-index: var(--z-header);
  height: var(--header-height);
  display: flex;
  align-items: center;
  transition: all var(--transition-base);
  background: var(--color-bg-white);
  border-bottom: 1px solid var(--color-border);
}

.header.scrolled {
  background: rgba(255, 255, 255, 0.97);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  box-shadow: var(--shadow-md);
}

.header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--container-padding);
}

/* Logo */
.header__logo {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  flex-shrink: 0;
}

.header__logo img {
  height: 32px;
  width: auto;
  border-radius: 0;
}

/* Navigation */
.nav {
  display: flex;
  align-items: center;
  gap: var(--space-8);
}

.nav__list {
  display: flex;
  align-items: center;
  gap: var(--space-6);
}

.nav__link {
  font-size: var(--fs-small);
  font-weight: var(--fw-semibold);
  color: var(--color-text);
  transition: all var(--transition-fast);
  position: relative;
  padding: var(--space-2) 0;
  border-bottom: 3px solid transparent;
}

.nav__link::after {
  display: none;
}

.nav__link:hover {
  color: var(--color-text);
  border-bottom-color: var(--color-primary);
}

.nav__link.active {
  color: var(--color-text);
  border-bottom-color: var(--color-primary);
}

.nav__cta {
  margin-left: var(--space-4);
}

/* Hamburger */
.hamburger {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 28px;
  height: 28px;
  cursor: pointer;
  z-index: calc(var(--z-header) + 10);
}

.hamburger__line {
  width: 100%;
  height: 2px;
  background: var(--color-text);
  border-radius: 2px;
  transition: all var(--transition-base);
  transform-origin: center;
}

.hamburger.active .hamburger__line:nth-child(1) {
  transform: rotate(45deg) translate(5px, 5px);
}

.hamburger.active .hamburger__line:nth-child(2) {
  opacity: 0;
}

.hamburger.active .hamburger__line:nth-child(3) {
  transform: rotate(-45deg) translate(5px, -5px);
}

/* Mobile nav overlay */
.nav-overlay {
  display: none;
}

/* ============================================
   FOOTER
   ============================================ */

.footer {
  background: var(--color-bg-dark);
  color: var(--color-text-light);
  padding: var(--space-16) 0 var(--space-8);
}

.footer__grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: var(--space-12);
  margin-bottom: var(--space-12);
}

.footer__brand {
  max-width: 320px;
}

.footer__logo {
  height: 28px;
  width: auto;
  margin-bottom: var(--space-4);
  border-radius: 0;
}

.footer__description {
  font-size: var(--fs-small);
  color: rgba(255, 255, 255, 0.5);
  line-height: var(--lh-body);
}

.footer__heading {
  font-size: var(--fs-small);
  font-weight: var(--fw-semibold);
  letter-spacing: 0.02em;
  margin-bottom: var(--space-6);
  color: rgba(255, 255, 255, 0.9);
}

.footer__links {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.footer__link {
  font-size: var(--fs-small);
  color: rgba(255, 255, 255, 0.5);
  transition: color var(--transition-fast);
}

.footer__link:hover {
  color: var(--color-secondary);
}

.footer__divider {
  height: 1px;
  background: rgba(255, 255, 255, 0.08);
  margin-bottom: var(--space-6);
}

.footer__bottom {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--space-4);
}

.footer__legal {
  font-size: var(--fs-xs);
  color: rgba(255, 255, 255, 0.35);
}

.footer__copy {
  font-size: var(--fs-xs);
  color: rgba(255, 255, 255, 0.35);
}

/* ============================================
   GRIDS
   ============================================ */

.grid {
  display: grid;
  gap: var(--space-6);
}

.grid--2 {
  grid-template-columns: repeat(2, 1fr);
}

.grid--3 {
  grid-template-columns: repeat(3, 1fr);
}

.grid--4 {
  grid-template-columns: repeat(4, 1fr);
}

/* Systems grid — 3x2 */
.grid--systems {
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-6);
}

/* ============================================
   PAGE HERO (for secondary pages)
   ============================================ */

.page-hero {
  padding: var(--space-16) 0 var(--space-12);
  background: var(--color-bg-dark);
  color: var(--color-text-light);
}

.page-hero h1 {
  font-size: var(--fs-h1);
  margin-bottom: var(--space-4);
}

.page-hero p {
  color: rgba(255, 255, 255, 0.7);
  max-width: 600px;
}

/* ============================================
   RESPONSIVE — LAYOUT
   ============================================ */

@media (max-width: 1199px) {
  .grid--3,
  .grid--systems {
    grid-template-columns: repeat(2, 1fr);
  }

  .grid--4 {
    grid-template-columns: repeat(2, 1fr);
  }

  .footer__grid {
    grid-template-columns: 1fr 1fr;
    gap: var(--space-8);
  }
}

@media (max-width: 767px) {
  /* Header — mobile */
  .hamburger {
    display: flex;
  }

  .nav {
    display: none;
  }

  .nav-overlay {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(26, 26, 26, 0.98);
    z-index: calc(var(--z-header) + 5);
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: var(--space-8);
  }

  .nav-overlay.active {
    display: flex;
  }

  .nav-overlay__list {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--space-8);
  }

  .nav-overlay__link {
    font-size: var(--fs-h3);
    font-weight: var(--fw-semibold);
    color: var(--color-text-light);
  }

  .nav-overlay__link:hover {
    color: var(--color-secondary);
  }

  .nav-overlay__cta {
    margin-top: var(--space-4);
  }

  /* Grids */
  .grid--2,
  .grid--3,
  .grid--4,
  .grid--systems {
    grid-template-columns: 1fr;
  }

  /* Footer */
  .footer__grid {
    grid-template-columns: 1fr;
    gap: var(--space-8);
  }

  .footer__bottom {
    flex-direction: column;
    text-align: center;
  }

  /* Section spacing */
  .section {
    padding: var(--space-16) 0;
  }

  .section__header {
    margin-bottom: var(--space-12);
  }

  /* Account for header */
  .page-hero {
    padding: calc(var(--header-height) + var(--space-12)) 0 var(--space-8);
  }
}