/**
 * header.css
 * БЭМ-блок: header
 * Шапка сайта с навигацией и burger-меню для мобильных
 */

/* ===========================
   Block: header
   =========================== */

.header {
  position: sticky;
  top: 0;
  z-index: var(--z-header);
  background-color: var(--color-bg);
  border-bottom: 1px solid var(--color-border);
  transition: box-shadow var(--transition-base);
}

.header_scrolled {
  box-shadow: var(--shadow-md);
  border-bottom-color: transparent;
}

.header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  max-width: 1280px;
  height: 60px;
  margin-left: auto;
  margin-right: auto;
  padding: 0 var(--spacing-md);
}

/* ===========================
   Element: logo
   =========================== */

.header__logo {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-bold);
  color: var(--color-primary);
  text-decoration: none;
  transition: opacity var(--transition-fast);
}

.header__logo:hover {
  color: var(--color-primary);
  opacity: 0.85;
}

.header__logo-icon {
  width: 36px;
  height: 36px;
  flex-shrink: 0;
}

.header__logo-text {
  display: none;
}

/* ===========================
   Element: nav
   =========================== */

.header__nav {
  position: fixed;
  top: 60px;
  left: 0;
  right: 0;
  bottom: 0;
  z-index: var(--z-header);
  display: flex;
  flex-direction: column;
  padding: var(--spacing-lg);
  background-color: var(--color-bg);
  transform: translateX(-100%);
  transition: transform var(--transition-base);
  overflow-y: auto;
}

.header__nav_open {
  transform: translateX(0);
}

.header__nav-list {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
}

.header__nav-item {
  border-bottom: 1px solid var(--color-border);
}

.header__nav-item:last-child {
  border-bottom: none;
}

.header__nav-link {
  display: block;
  padding: var(--spacing-md);
  font-size: var(--font-size-lg);
  color: var(--color-text);
  text-decoration: none;
  transition: color var(--transition-fast), background-color var(--transition-fast);
}

.header__nav-link:hover {
  color: var(--color-accent);
  background-color: var(--color-bg-alt);
}

.header__nav-link_active {
  color: var(--color-accent);
  font-weight: var(--font-weight-semibold);
}

/* ===========================
   Element: actions (auth buttons)
   =========================== */

.header__actions {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
  margin-top: var(--spacing-lg);
  padding-top: var(--spacing-lg);
  border-top: 1px solid var(--color-border);
}

.header__actions .button {
  width: 100%;
  justify-content: center;
}

/* ===========================
   Element: burger
   =========================== */

.header__burger {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  width: 44px;
  height: 44px;
  padding: var(--spacing-sm);
  background: none;
  border: none;
  cursor: pointer;
}

.header__burger-line {
  display: block;
  width: 24px;
  height: 2px;
  background-color: var(--color-primary);
  transition: transform var(--transition-fast), opacity var(--transition-fast);
}

.header__burger-line:nth-child(1) {
  transform: translateY(-6px);
}

.header__burger-line:nth-child(3) {
  transform: translateY(6px);
}

/* Burger open state */
.header__burger_open .header__burger-line:nth-child(1) {
  transform: translateY(0) rotate(45deg);
}

.header__burger_open .header__burger-line:nth-child(2) {
  opacity: 0;
}

.header__burger_open .header__burger-line:nth-child(3) {
  transform: translateY(0) rotate(-45deg);
}

/* ===========================
   Overlay for mobile menu
   =========================== */

.header__overlay {
  position: fixed;
  top: 60px;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: rgba(0, 0, 0, 0.5);
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--transition-base), visibility var(--transition-base);
  z-index: calc(var(--z-header) - 1);
}

.header__overlay_visible {
  opacity: 1;
  visibility: visible;
}

/* ===========================
   Media Queries
   =========================== */

/* Small devices (480px and up) */
@media (min-width: 480px) {
  .header__logo-icon {
    width: 40px;
    height: 40px;
  }
}

/* Medium devices - show logo text (600px and up) */
@media (min-width: 600px) {
  .header__logo-text {
    display: block;
  }
}

/* Medium devices (768px and up) */
@media (min-width: 768px) {
  .header__inner {
    height: 70px;
    padding: 0 var(--spacing-xl);
  }

  .header__logo {
    font-size: var(--font-size-xl);
  }

  .header__logo-icon {
    width: 48px;
    height: 48px;
  }

  /* Desktop navigation */
  .header__nav {
    position: static;
    flex-direction: row;
    align-items: center;
    padding: 0;
    background-color: transparent;
    transform: none;
    overflow: visible;
  }

  .header__nav-list {
    flex-direction: row;
    gap: 0;
  }

  .header__nav-item {
    border-bottom: none;
  }

  .header__nav-link {
    padding: var(--spacing-sm) var(--spacing-md);
    font-size: var(--font-size-base);
    border-radius: var(--radius-md);
  }

  .header__nav-link:hover {
    background-color: var(--color-bg-alt);
  }

  .header__actions {
    flex-direction: row;
    margin-top: 0;
    margin-left: var(--spacing-lg);
    padding-top: 0;
    border-top: none;
  }

  .header__actions .button {
    width: auto;
  }

  /* Hide burger on desktop */
  .header__burger {
    display: none;
  }

  .header__overlay {
    display: none;
  }
}

/* Large devices (1024px and up) */
@media (min-width: 1024px) {
  .header__inner {
    padding: 0 var(--spacing-2xl);
  }

  .header__nav-link {
    padding: var(--spacing-sm) var(--spacing-lg);
  }

  .header__actions {
    gap: var(--spacing-md);
  }
}

/* ===========================
   Modifier: container for chat page
   =========================== */

.header__container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 60px;
  padding: 0 var(--spacing-md);
}

@media (min-width: 768px) {
  .header__container {
    height: 70px;
    padding: 0 var(--spacing-lg);
  }
}

@media (min-width: 1024px) {
  .header__container {
    height: 80px;
  }
}

/* Button style for nav items */
.header__nav-item_button {
  padding: var(--spacing-sm) var(--spacing-md);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  color: var(--color-text);
  background: none;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: background-color var(--transition-fast), border-color var(--transition-fast);
}

.header__nav-item_button:hover {
  background-color: var(--color-bg-alt);
  border-color: var(--color-text-muted);
}

/* ===========================
   Modifier: header--chat (Chat page)
   =========================== */

.header--chat {
  background-color: var(--color-primary);
  border-bottom-color: rgba(255, 255, 255, 0.1);
}

.header--chat .header__logo,
.header--chat .header__logo-text {
  color: var(--color-bg);
}

/* ===========================
   Element: user-area (username + logout)
   =========================== */

.header__user-area {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
}

.header__username {
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  color: rgba(255, 255, 255, 0.8);
  max-width: 150px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

@media (max-width: 479px) {
  .header__username {
    display: none;
  }
}

.header__logout-btn {
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
  padding: var(--spacing-xs) var(--spacing-sm);
  font-size: var(--font-size-sm);
  color: rgba(255, 255, 255, 0.9);
  background: transparent;
  border: 1px solid rgba(255, 255, 255, 0.3);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: background-color var(--transition-fast);
}

.header__logout-btn:hover {
  background-color: rgba(255, 255, 255, 0.1);
}