/**
 * Responsive Navigation System - Lightning Talk Circle
 * マルチデバイス対応ナビゲーションシステム
 */

/* =============================================================================
   CSS Variables for Responsive Navigation
   ============================================================================= */

:root {
  /* Navigation Heights */
  --nav-height-mobile: 60px;
  --nav-height-tablet: 70px;
  --nav-height-desktop: 80px;

  /* Breakpoints */
  --breakpoint-mobile: 375px;
  --breakpoint-tablet: 768px;
  --breakpoint-desktop: 1024px;

  /* Z-index Stack */
  --z-navigation: 1000;
  --z-mobile-menu: 1001;
  --z-overlay: 999;

  /* Animation Timing */
  --nav-transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --mobile-menu-transition: 0.35s cubic-bezier(0.25, 0.8, 0.25, 1);

  /* Contrast-optimized colors */
  --nav-text-primary: #1a202c;
  --nav-text-shadow: 0 1px 2px rgba(255, 255, 255, 0.8);
  --nav-primary-color: #4a90e2;
  --nav-primary-light: rgba(74, 144, 226, 0.2);

  /* Touch Targets */
  --touch-target-min: 44px;
  --touch-target-comfortable: 48px;
}

/* =============================================================================
   Base Header Styles
   ============================================================================= */

.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height-mobile);
  background: rgba(255, 255, 255, 0.99);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 3px solid var(--color-primary-500, #4a90e2);
  z-index: var(--z-navigation);
  transition: all var(--nav-transition);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
}

.header--scrolled {
  background: rgba(248, 249, 250, 0.99);
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.2);
}

.header__container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
  padding: 0 16px;
  max-width: 1200px;
  margin: 0 auto;
}

/* =============================================================================
   Logo Component
   ============================================================================= */

.logo-container {
  display: flex;
  align-items: center;
  gap: 12px;
  z-index: var(--z-navigation);
}

.logo-image {
  height: 32px;
  width: auto;
  transition: transform var(--nav-transition);
}

.logo-text {
  font-size: 18px;
  font-weight: 700;
  color: var(--color-primary, #4a90e2);
  white-space: nowrap;
}

/* =============================================================================
   Desktop Navigation
   ============================================================================= */

.nav-links {
  display: none;
  list-style: none;
  margin: 0;
  padding: 0;
  gap: 8px;
}

.nav-link {
  display: block;
  padding: 8px 16px;
  color: var(--nav-text-primary) !important;
  text-decoration: none;
  font-weight: 600;
  font-size: 14px;
  border-radius: 8px;
  transition: all var(--nav-transition);
  white-space: nowrap;
  text-shadow: var(--nav-text-shadow);
}

.nav-link:hover {
  background-color: var(--nav-primary-light);
  color: var(--nav-primary-color) !important;
  text-shadow: none;
}

.nav-link:focus {
  outline: 2px solid var(--color-primary, #4a90e2);
  outline-offset: 2px;
}

/* =============================================================================
   Mobile Menu Toggle
   ============================================================================= */

.mobile-menu-toggle {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  width: var(--touch-target-comfortable);
  height: var(--touch-target-comfortable);
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
  border-radius: 8px;
  transition: background-color var(--nav-transition);
}

.mobile-menu-toggle:hover {
  background-color: #f3f4f6;
}

.mobile-menu-toggle:focus {
  outline: 2px solid #2563eb;
  outline-offset: 2px;
}

.mobile-menu-toggle__line {
  width: 24px;
  height: 2px;
  background-color: var(--color-text-primary, #2c3e50);
  margin: 2px 0;
  transition: all var(--nav-transition);
  transform-origin: center;
}

/* Active State Animation */
.mobile-menu-toggle--active .mobile-menu-toggle__line:nth-child(1) {
  transform: rotate(45deg) translate(6px, 6px);
}

.mobile-menu-toggle--active .mobile-menu-toggle__line:nth-child(2) {
  opacity: 0;
}

.mobile-menu-toggle--active .mobile-menu-toggle__line:nth-child(3) {
  transform: rotate(-45deg) translate(6px, -6px);
}

/* =============================================================================
   Mobile Menu Overlay
   ============================================================================= */

.mobile-menu-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100vh;
  background-color: rgba(0, 0, 0, 0.5);
  z-index: var(--z-overlay);
  opacity: 0;
  visibility: hidden;
  transition: all var(--mobile-menu-transition);
}

.mobile-menu-overlay--active {
  opacity: 1;
  visibility: visible;
}

/* =============================================================================
   Mobile Menu Panel
   ============================================================================= */

.mobile-menu {
  position: fixed;
  top: 0;
  right: -100%;
  width: 280px;
  max-width: 80vw;
  height: 100vh;
  background: #ffffff;
  z-index: var(--z-mobile-menu);
  padding: 80px 24px 24px;
  overflow-y: auto;
  transition: right var(--mobile-menu-transition);
  box-shadow: -4px 0 20px rgba(0, 0, 0, 0.1);
}

.mobile-menu--active {
  right: 0;
}

.mobile-menu__list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.mobile-menu__item {
  margin-bottom: 8px;
}

.mobile-menu__link {
  display: flex;
  align-items: center;
  padding: 16px 0;
  color: var(--color-text-primary, #2c3e50);
  text-decoration: none;
  font-weight: 500;
  font-size: 16px;
  border-bottom: 1px solid #f3f4f6;
  transition: color var(--nav-transition);
  min-height: var(--touch-target-min);
}

.mobile-menu__link:hover {
  color: var(--color-primary, #4a90e2);
}

.mobile-menu__link:focus {
  outline: 2px solid var(--color-primary, #4a90e2);
  outline-offset: 2px;
}

/* Mobile Auth Section */
.mobile-menu__auth {
  margin-top: 32px;
  padding-top: 24px;
  border-top: 1px solid #e5e7eb;
}

/* =============================================================================
   Priority Navigation Items
   ============================================================================= */

/* Primary (Always Visible) */
.nav-item--primary {
  display: block;
}

/* Secondary (Tablet+) */
.nav-item--secondary {
  display: none;
}

/* Tertiary (Desktop Only) */
.nav-item--tertiary {
  display: none;
}

/* =============================================================================
   Tablet Styles (768px+)
   ============================================================================= */

@media (min-width: 768px) {
  .header {
    height: var(--nav-height-tablet);
  }

  .header__container {
    padding: 0 24px;
  }

  .logo-image {
    height: 36px;
  }

  .logo-text {
    font-size: 20px;
  }

  /* Show secondary navigation items */
  .nav-item--secondary {
    display: block;
  }

  /* Simplified mobile menu for tablet */
  .mobile-menu {
    width: 320px;
  }

  .nav-links {
    display: flex;
  }

  .mobile-menu-toggle {
    display: none;
  }
}

/* =============================================================================
   Desktop Styles (1024px+)
   ============================================================================= */

@media (min-width: 1024px) {
  .header {
    height: var(--nav-height-desktop);
  }

  .header__container {
    padding: 0 32px;
  }

  .logo-image {
    height: 40px;
  }

  .logo-text {
    font-size: 22px;
  }

  .nav-links {
    gap: 12px;
  }

  .nav-link {
    font-size: 15px;
    padding: 10px 18px;
  }

  /* Show all navigation items */
  .nav-item--tertiary {
    display: block;
  }

  /* Hide mobile menu completely */
  .mobile-menu-toggle {
    display: none;
  }
}

/* =============================================================================
   Large Desktop Styles (1440px+)
   ============================================================================= */

@media (min-width: 1440px) {
  .header__container {
    max-width: 1400px;
  }

  .nav-links {
    gap: 16px;
  }

  .nav-link {
    padding: 12px 20px;
  }
}

/* =============================================================================
   Accessibility Enhancements
   ============================================================================= */

/* Reduce motion for users who prefer it */
@media (prefers-reduced-motion: reduce) {
  .header,
  .mobile-menu-toggle__line,
  .mobile-menu,
  .mobile-menu-overlay,
  .nav-link {
    transition: none;
  }
}

/* High contrast mode support */
@media (prefers-contrast: high) {
  .header {
    border-bottom: 2px solid #000;
  }

  .nav-link:focus,
  .mobile-menu-toggle:focus {
    outline: 3px solid #000;
  }
}

/* Dark mode support */
@media (prefers-color-scheme: dark) {
  .header {
    background: rgba(17, 24, 39, 0.95);
    border-bottom-color: rgba(255, 255, 255, 0.1);
  }

  .nav-link,
  .mobile-menu__link {
    color: #f9fafb;
  }

  .nav-link:hover {
    background-color: rgba(255, 255, 255, 0.1);
    color: #60a5fa;
  }

  .mobile-menu {
    background: #111827;
  }

  .mobile-menu-toggle__line {
    background-color: #f9fafb;
  }
}

/* =============================================================================
   Touch Device Optimizations
   ============================================================================= */

@media (hover: none) and (pointer: coarse) {
  /* Increase touch targets on touch devices */
  .nav-link {
    min-height: var(--touch-target-min);
    padding: 12px 16px;
  }

  .mobile-menu__link {
    min-height: var(--touch-target-comfortable);
    padding: 18px 0;
  }

  /* Remove hover effects on touch devices */
  .nav-link:hover,
  .mobile-menu-toggle:hover {
    background-color: transparent;
  }

  /* Add tap highlight for better feedback */
  .nav-link:active {
    background-color: #e5e7eb;
  }

  .mobile-menu__link:active {
    color: #2563eb;
    background-color: #f3f4f6;
  }
}