/* =========================================================
   04-LAYOUT.CSS
   Structural elements: container, sections, header, footer.
   ========================================================= */

.container {
  width: 100%;
  max-width: var(--container-max);
  margin-inline: auto;
  padding-inline: var(--container-padding);
}

.container--narrow {
  max-width: var(--container-narrow);
}

.section {
  padding-block: var(--space-16);
}

.section--tight {
  padding-block: var(--space-10);
}

.section--dark {
  background: var(--color-secondary);
  color: var(--color-text-inverse);
}

.section--dark h1,
.section--dark h2,
.section--dark h3,
.section--dark h4 {
  color: var(--color-text-inverse);
}

.section--dark p {
  color: rgba(255, 255, 255, 0.75);
}

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

/* -------------- HEADER -------------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--header-h);
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: saturate(180%) blur(14px);
  -webkit-backdrop-filter: saturate(180%) blur(14px);
  border-bottom: 1px solid transparent;
  transition: border-color var(--dur) var(--ease);
}

.site-header.is-scrolled {
  border-bottom-color: var(--color-border);
}

.site-header__inner {
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-6);
}

.site-header__brand {
  display: inline-flex;
  align-items: center;
  gap: var(--space-3);
  font-family: var(--font-display);
  font-weight: 800;
  font-size: var(--fs-md);
  letter-spacing: var(--tracking-tight);
  color: var(--color-secondary);
}

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

.site-header__logo {
  width: 32px;
  height: 32px;
  display: grid;
  place-items: center;
  background: var(--color-primary);
  color: #fff;
  border-radius: 6px;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 14px;
  letter-spacing: 0;
}

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

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

.site-nav__link {
  font-size: var(--fs-sm);
  font-weight: 500;
  color: var(--color-secondary);
  position: relative;
  padding-block: var(--space-2);
}

.site-nav__link::after {
  content: '';
  position: absolute;
  left: 0;
  bottom: 0;
  width: 0;
  height: 2px;
  background: var(--color-primary);
  transition: width var(--dur) var(--ease);
}

.site-nav__link:hover,
.site-nav__link.is-active {
  color: var(--color-primary);
}

.site-nav__link.is-active::after,
.site-nav__link:hover::after {
  width: 100%;
}

/* Mobile menu toggle */
.nav-toggle {
  display: none;
  width: 40px;
  height: 40px;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-sm);
}

.nav-toggle__bar {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--color-secondary);
  position: relative;
  transition: transform var(--dur) var(--ease), background var(--dur) var(--ease);
}

.nav-toggle__bar::before,
.nav-toggle__bar::after {
  content: '';
  position: absolute;
  left: 0;
  width: 22px;
  height: 2px;
  background: var(--color-secondary);
  transition: transform var(--dur) var(--ease), top var(--dur) var(--ease);
}

.nav-toggle__bar::before { top: -7px; }
.nav-toggle__bar::after  { top: 7px; }

.nav-toggle.is-open .nav-toggle__bar { background: transparent; }
.nav-toggle.is-open .nav-toggle__bar::before { top: 0; transform: rotate(45deg); }
.nav-toggle.is-open .nav-toggle__bar::after  { top: 0; transform: rotate(-45deg); }

@media (max-width: 900px) {
  .nav-toggle { display: inline-flex; }

  .site-nav {
    position: fixed;
    top: var(--header-h);
    left: 0;
    right: 0;
    background: #fff;
    border-top: 1px solid var(--color-border);
    flex-direction: column;
    align-items: stretch;
    padding: var(--space-6) var(--container-padding);
    gap: var(--space-2);
    transform: translateY(-8px);
    opacity: 0;
    pointer-events: none;
    transition: opacity var(--dur) var(--ease), transform var(--dur) var(--ease);
  }

  .site-nav.is-open {
    opacity: 1;
    transform: translateY(0);
    pointer-events: auto;
    box-shadow: var(--shadow-md);
  }

  .site-nav__list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
  }

  .site-nav__link {
    padding-block: var(--space-4);
    border-bottom: 1px solid var(--color-border);
    font-size: var(--fs-base);
  }

  .site-nav__link::after { display: none; }

  .site-nav .btn {
    margin-top: var(--space-4);
    width: 100%;
    justify-content: center;
  }
}

/* -------------- FOOTER -------------- */
.site-footer {
  background: var(--color-secondary);
  color: rgba(255, 255, 255, 0.75);
  padding-block: var(--space-12) var(--space-6);
}

.site-footer__grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr 1fr;
  gap: var(--space-8);
  margin-bottom: var(--space-10);
}

@media (max-width: 800px) {
  .site-footer__grid {
    grid-template-columns: 1fr 1fr;
    gap: var(--space-8) var(--space-6);
  }
  .site-footer__brand-col { grid-column: 1 / -1; }
}

.site-footer__brand-name {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: var(--fs-lg);
  color: #fff;
  margin-bottom: var(--space-4);
  letter-spacing: var(--tracking-tight);
}

.site-footer__tagline {
  font-size: var(--fs-sm);
  line-height: var(--lh-relaxed);
  max-width: 32ch;
  color: #ffffff
}

.site-footer__heading {
  font-family: var(--font-body);
  font-size: var(--fs-xs);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: var(--tracking-wider);
  color: rgba(255, 255, 255, 0.5);
  margin-bottom: var(--space-5);
}

.site-footer__list li { margin-bottom: var(--space-3); }

.site-footer__list a {
  font-size: var(--fs-sm);
  color: rgba(255, 255, 255, 0.75);
}

.site-footer__list a:hover { color: var(--color-primary); }

.site-footer__bottom {
  padding-top: var(--space-6);
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: var(--space-4);
  flex-wrap: wrap;
  font-size: var(--fs-xs);
  color: rgba(255, 255, 255, 0.5);
}

.site-footer__socials {
  display: flex;
  gap: var(--space-3);
}

.site-footer__socials a {
  width: 36px;
  height: 36px;
  display: grid;
  place-items: center;
  border: 1px solid rgba(255, 255, 255, 0.15);
  border-radius: 50%;
  transition: all var(--dur) var(--ease);
}

.site-footer__socials a:hover {
  background: var(--color-primary);
  border-color: var(--color-primary);
  color: #fff;
}

.site-footer__socials svg {
  width: 16px;
  height: 16px;
  fill: currentColor;
}

/* -------------- 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); }

@media (max-width: 900px) {
  .grid-3, .grid-4 { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 640px) {
  .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
}