/* ===== Header Styles (Mobile-first) ===== */

.header {
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: var(--color-header-bg);
  border-bottom: 1px solid var(--color-header-border);
  box-shadow: var(--shadow-sm);
  height: var(--header-height);
}

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

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

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

.header__logo-icon {
  width: 36px;
  height: 36px;
  background-color: var(--color-accent);
  border-radius: var(--border-radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.header__logo-icon svg {
  width: 22px;
  height: 22px;
  fill: #ffffff;
}

/* ===== Mobile Navigation (Base: 320px+) ===== */

.burger-btn {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  width: 40px;
  height: 40px;
  border-radius: var(--border-radius-md);
  background-color: transparent;
  cursor: pointer;
  gap: 5px;
}

.burger-btn__line {
  display: block;
  width: 22px;
  height: 2px;
  background-color: var(--color-text-primary);
  border-radius: 2px;
  transition: transform var(--transition-normal), opacity var(--transition-normal);
}

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

.burger-btn.active .burger-btn__line:nth-child(2) {
  opacity: 0;
}

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

.header__nav {
  position: fixed;
  top: var(--header-height);
  left: 0;
  right: 0;
  background-color: var(--color-header-bg);
  border-bottom: 1px solid var(--color-header-border);
  flex-direction: column;
  padding: var(--spacing-lg);
  transform: translateY(-100%);
  opacity: 0;
  visibility: hidden;
  transition: transform var(--transition-normal), opacity var(--transition-normal), visibility var(--transition-normal);
  box-shadow: var(--shadow-lg);
  z-index: 99;
}

.header__nav.open {
  transform: translateY(0);
  opacity: 1;
  visibility: visible;
}

.header__nav-list {
  display: flex;
  flex-direction: column;
  width: 100%;
  gap: var(--spacing-xs);
}

.header__nav-link {
  display: block;
  width: 100%;
  text-align: center;
  padding: var(--spacing-md);
  color: var(--color-text-secondary);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  border-radius: var(--border-radius-md);
  transition: background-color var(--transition-fast), color var(--transition-fast);
}

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

.header__nav-link--active {
  color: var(--color-accent);
  background-color: var(--color-accent-light);
}

.header__actions {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  margin-top: var(--spacing-md);
  padding-top: var(--spacing-md);
  border-top: 1px solid var(--color-border);
}

/* Theme Toggle Button */
.theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: var(--border-radius-full);
  background-color: var(--color-bg-secondary);
  color: var(--color-text-secondary);
  transition: background-color var(--transition-fast), color var(--transition-fast);
}

.theme-toggle:hover {
  background-color: var(--color-bg-tertiary);
  color: var(--color-accent);
}

.theme-toggle__icon {
  width: 20px;
  height: 20px;
}

/* ===== Desktop Navigation (768px+) ===== */
@media (min-width: 769px) {
  .burger-btn {
    display: none;
  }

  .header__nav {
    position: static;
    top: auto;
    left: auto;
    right: auto;
    background-color: transparent;
    border-bottom: none;
    flex-direction: row;
    padding: 0;
    transform: none;
    opacity: 1;
    visibility: visible;
    transition: none;
    box-shadow: none;
    z-index: auto;
  }

  .header__nav-list {
    flex-direction: row;
    width: auto;
    align-items: center;
    gap: var(--spacing-xs);
  }

  .header__nav-link {
    width: auto;
    text-align: left;
    padding: var(--spacing-sm) var(--spacing-md);
  }

  .header__actions {
    margin-top: 0;
    padding-top: 0;
    border-top: none;
    justify-content: flex-end;
  }
}