/* ============================================================
   layout.css — Container, Grid, Section Spacing, Page Layout
   tgport.ru Design System
   ============================================================ */

/* --- Container --- */

.container {
  width: 100%;
  max-width: 1280px;
  margin-inline: auto;
  padding-inline: var(--space-lg);
}

.container--sm {
  max-width: 720px;
}

.container--narrow {
  max-width: 960px;
}

.container--wide {
  max-width: 1440px;
}

.container--prose {
  max-width: 720px;
}

/* --- Grid System --- */

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

.grid--2 { grid-template-columns: repeat(2, 1fr); }
.grid--3 { grid-template-columns: repeat(3, 1fr); }
.grid--4 { grid-template-columns: repeat(4, 1fr); }

.grid--auto-fit {
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
}

.grid--auto-fill {
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
}

/* --- Flex Utilities --- */

.flex        { display: flex; }
.flex--col   { flex-direction: column; }
.flex--wrap  { flex-wrap: wrap; }
.flex--center {
  align-items: center;
  justify-content: center;
}
.flex--between {
  align-items: center;
  justify-content: space-between;
}
.flex--start {
  align-items: flex-start;
}
.flex--end {
  align-items: flex-end;
}
.gap-xs  { gap: var(--space-xs); }
.gap-sm  { gap: var(--space-sm); }
.gap-md  { gap: var(--space-md); }
.gap-lg  { gap: var(--space-lg); }
.gap-xl  { gap: var(--space-xl); }
.gap-2xl { gap: var(--space-2xl); }

/* --- Section Spacing --- */

.section {
  padding-block: var(--space-3xl);
}

.section--sm {
  padding-block: var(--space-2xl);
}

.section--lg {
  padding-block: var(--space-4xl);
}

.section--xl {
  padding-block: var(--space-5xl);
}

.section__header {
  margin-bottom: var(--space-2xl);
  text-align: center;
}

.section__title {
  font-size: var(--text-3xl);
  margin-bottom: var(--space-sm);
  text-align: center;
}

.section__subtitle {
  font-size: var(--text-md);
  color: var(--color-text-secondary);
  max-width: 640px;
  margin-inline: auto;
  text-align: center;
}

/* --- Page Layout --- */

.page {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

.page__main {
  flex: 1;
}

/* --- Header --- */

.header {
  position: sticky;
  top: 0;
  z-index: var(--z-sticky);
  background: var(--header-bg);
  border-bottom: var(--border-w) solid var(--header-border);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  transition:
    background var(--transition-theme),
    border-color var(--transition-theme);
}

.header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.header__logo {
  font-size: var(--text-lg);
  font-weight: 700;
  color: var(--color-heading);
  text-decoration: none;
  letter-spacing: -0.02em;
  transition: color var(--transition-fast);
}

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

.header__nav {
  display: none;
  align-items: center;
  gap: var(--space-lg);
}

.header__nav-list {
  display: flex;
  align-items: center;
  gap: var(--space-lg);
  list-style: none;
  margin: 0;
  padding: 0;
}

.header__nav-link {
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-text-secondary);
  text-decoration: none;
  transition: color var(--transition-fast);
  position: relative;
}

.header__nav-link:hover,
.header__nav-link--active {
  color: var(--color-heading);
}

.header__nav-link--active::after {
  content: "";
  position: absolute;
  bottom: -4px;
  left: 0;
  right: 0;
  height: 2px;
  background: var(--color-accent);
  border-radius: var(--radius-full);
}

.header__nav-actions {
  margin-left: var(--space-sm);
}

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

.header__theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: var(--radius-md);
  color: var(--color-text-secondary);
  transition:
    background var(--transition-fast),
    color var(--transition-fast);
}

.header__theme-toggle:hover {
  background: var(--color-surface-hover);
  color: var(--color-heading);
}

.header__theme-toggle svg {
  width: 20px;
  height: 20px;
}

.header__theme-toggle .icon--sun {
  display: none;
}

[data-theme="dark"] .header__theme-toggle .icon--sun {
  display: block;
}

[data-theme="dark"] .header__theme-toggle .icon--moon {
  display: none;
}

.header__logo {
  color: var(--color-heading);
  transition: color var(--transition-theme);
}

.header__logo img {
  display: block;
}

.header__burger {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  color: var(--color-text);
  border-radius: var(--radius-md);
  transition: background var(--transition-fast);
  flex-direction: column;
  gap: 5px;
}

.header__burger span {
  display: block;
  width: 20px;
  height: 2px;
  background: currentColor;
  border-radius: 1px;
  transition: transform var(--transition-fast), opacity var(--transition-fast);
}

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

/* --- Header Scrolled --- */

.header--scrolled {
  box-shadow: var(--shadow-sm);
}

/* --- Mobile Nav (is-open toggle on header__nav) --- */

body.menu-open {
  overflow: hidden;
}

/* --- Footer --- */

.footer {
  border-top: var(--border-w) solid var(--color-border);
  padding-block: var(--space-3xl);
  background: var(--color-bg-sunken);
  transition:
    background var(--transition-theme),
    border-color var(--transition-theme);
}

.footer__grid {
  display: grid;
  gap: var(--space-2xl);
}

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

.footer__logo {
  display: inline-block;
}

.footer__logo img {
  display: block;
}

[data-theme="dark"] .footer__logo img,
[data-theme="dark"] .header__logo img {
  filter: invert(1) hue-rotate(180deg);
}

.footer__desc {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  margin-top: var(--space-sm);
  line-height: 1.6;
}

.footer__social {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  margin-top: var(--space-md);
}

.footer__social-link {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: var(--radius-md);
  transition: transform var(--transition-fast), opacity var(--transition-fast);
}

.footer__social-link:hover {
  transform: translateY(-2px);
  opacity: 0.85;
}

.footer__social-link img {
  width: 28px;
  height: 28px;
  border-radius: var(--radius-sm);
}

.footer__links {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 0;
}

.footer__links a {
  display: block;
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  padding-block: var(--space-2xs);
  text-decoration: none;
  transition: color var(--transition-fast);
}

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

.footer__link {
  display: block;
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  padding-block: var(--space-2xs);
  transition: color var(--transition-fast);
}

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

.footer__bottom {
  margin-top: var(--space-2xl);
  padding-top: var(--space-lg);
  border-top: var(--border-w) solid var(--color-border);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-sm);
  text-align: center;
}

.footer__copy {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
}

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

.footer__legal a {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  text-decoration: none;
  transition: color var(--transition-fast);
}

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

/* --- Theme Toggle --- */

.theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: var(--radius-md);
  color: var(--color-text-secondary);
  transition:
    background var(--transition-fast),
    color var(--transition-fast);
}

.theme-toggle:hover {
  background: var(--color-surface-hover);
  color: var(--color-heading);
}

.theme-toggle svg {
  width: 20px;
  height: 20px;
}

/* --- Divider --- */

.divider {
  height: var(--border-w);
  background: var(--color-border);
  border: none;
  margin-block: var(--space-2xl);
  transition: background var(--transition-theme);
}

/* --- Section Utilities --- */

.section--alt {
  background: var(--color-bg-sunken);
  transition: background var(--transition-theme);
}

.section__note {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  margin-top: var(--space-lg);
  line-height: 1.6;
  text-align: center;
}

.section__actions {
  margin-top: var(--space-xl);
  display: flex;
  justify-content: center;
  gap: var(--space-md);
}

/* --- Breadcrumb --- */

.breadcrumb {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--space-2xs);
  font-size: var(--text-sm);
  margin-bottom: var(--space-lg);
}

.breadcrumb__link {
  color: var(--color-text-secondary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

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

.breadcrumb__sep {
  color: var(--color-text-muted);
  user-select: none;
}

.breadcrumb__current {
  color: var(--color-heading);
  font-weight: 500;
}

/* ============================================================
   Responsive Breakpoints
   Mobile-first: 360 base → 768 → 1024 → 1280 → 1440
   ============================================================ */

@media (min-width: 768px) {
  .container {
    padding-inline: var(--space-xl);
  }

  .header__inner {
    height: 72px;
  }

  .header__nav {
    display: flex;
  }

  .header__burger {
    display: none;
  }

  .section {
    padding-block: var(--space-4xl);
  }

  .section__title {
    font-size: var(--text-4xl);
  }

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

  .footer__bottom {
    flex-direction: row;
    justify-content: space-between;
    text-align: left;
  }

  .grid--2-tablet { grid-template-columns: repeat(2, 1fr); }
  .grid--3-tablet { grid-template-columns: repeat(3, 1fr); }
}

@media (min-width: 1024px) {
  .container {
    padding-inline: var(--space-2xl);
  }

  .header__inner {
    height: 80px;
  }

  .section--lg {
    padding-block: var(--space-5xl);
  }

  .footer__grid {
    grid-template-columns: 2fr repeat(3, 1fr);
  }

  .grid--3-desktop { grid-template-columns: repeat(3, 1fr); }
  .grid--4-desktop { grid-template-columns: repeat(4, 1fr); }
}

@media (min-width: 1280px) {
  .section__title {
    font-size: var(--text-5xl);
  }
}

@media (max-width: 767px) {
  .grid--2,
  .grid--3,
  .grid--4 {
    grid-template-columns: 1fr;
  }

  .section__title {
    font-size: var(--text-2xl);
  }

  .section__subtitle {
    font-size: var(--text-base);
  }

  .header__nav {
    position: fixed;
    top: 0;
    right: 0;
    bottom: 0;
    width: 300px;
    max-width: 85vw;
    background: var(--color-bg-elevated);
    padding: var(--space-xl);
    flex-direction: column;
    gap: var(--space-md);
    z-index: var(--z-overlay);
    transform: translateX(100%);
    transition: transform var(--transition-base);
    box-shadow: var(--shadow-2xl);
  }

  .header__nav.is-open {
    display: flex;
    transform: translateX(0);
  }

  .header__nav-list {
    flex-direction: column;
    gap: 0;
    width: 100%;
  }

  .header__nav-list li {
    width: 100%;
  }

  .header__nav-link {
    display: block;
    padding: var(--space-sm) 0;
    font-size: var(--text-md);
    border-bottom: var(--border-w) solid var(--color-border);
  }

  .header__nav-actions {
    margin-left: 0;
    margin-top: var(--space-md);
    width: 100%;
  }

  .header__nav-actions .btn {
    width: 100%;
    justify-content: center;
  }

  .hide-mobile { display: none !important; }
}

@media (min-width: 768px) {
  .hide-tablet-up { display: none !important; }
}

@media (min-width: 1024px) {
  .hide-desktop { display: none !important; }
}