/* ============================================
   Responsive Design - Mobile First
   ============================================ */

/* ============================================
   Base (Mobile): < 480px
   Mobile-First 預設樣式
   ============================================ */

/* Typography - Mobile defaults */
h1 {
  font-size: var(--font-size-2xl);
}

h2 {
  font-size: var(--font-size-xl);
}

h3 {
  font-size: var(--font-size-lg);
}

/* Container - Mobile defaults */
.container,
.container-small,
.container-large {
  padding: 0 var(--spacing-4);
}

/* Grid - Mobile: 全部單欄 */
.grid-2,
.grid-3,
.grid-4 {
  grid-template-columns: 1fr;
  gap: var(--spacing-4);
}

/* Navigation - Mobile defaults */
.top-nav {
  height: 64px;
}

.nav-links {
  display: none !important;
}

.hamburger-menu {
  display: block !important;
}

/* 手機版：隱藏 nav-actions，但主題切換按鈕獨立顯示 */
.nav-actions {
  display: none;
}

/* 導航容器需要 position relative */
.top-nav-container {
  position: relative;
}

/* 主題切換按鈕在手機版強制顯示 */
#theme-toggle-btn,
.mobile-theme-toggle {
  display: flex !important;
  position: absolute;
  right: 56px;
  top: 50%;
  transform: translateY(-50%);
}

/* 漢堡選單按鈕固定在右側 */
.hamburger-menu {
  position: absolute;
  right: 8px;
  top: 50%;
  transform: translateY(-50%);
}

/* Sidebar - Mobile: 預設隱藏在左側 */
.sidebar {
  position: fixed;
  left: -240px;
  top: 64px;
  width: 240px;
  height: calc(100vh - 64px);
  background: var(--color-bg-secondary);
  border-right: 1px solid var(--color-border-default);
  z-index: 999;
  transition: left var(--transition-base);
}

.sidebar.active {
  left: 0;
}

/* Sidebar overlay for mobile */
.sidebar-overlay {
  position: fixed;
  inset: 0;
  top: 64px;
  background: rgba(0, 0, 0, 0.5);
  opacity: 0;
  visibility: hidden;
  z-index: 998;
  transition: opacity 0.3s, visibility 0.3s;
}

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

/* Prevent body scroll when sidebar open */
body.sidebar-open {
  overflow: hidden;
}

/* Page Layout - Mobile: 單欄 */
.page-layout {
  display: block;
  margin-top: 64px;
}

.page-layout main {
  width: 100%;
  padding: var(--spacing-4);
}

/* Section Spacing - Mobile */
section {
  padding: var(--spacing-10) 0;
}

section.section-spacious {
  padding: var(--spacing-12) 0;
}

/* Footer - Mobile: 單欄，全寬 */
footer .container {
  display: block;
  width: 100%;
}

footer .container > div {
  margin-bottom: var(--spacing-6);
}

/* Buttons - Mobile: 特定場景全寬 */
.form-actions .btn,
.modal-footer .btn {
  width: 100%;
}

/* Hero buttons: 手機版垂直排列 */
.hero-buttons {
  flex-direction: column;
  align-items: center;
}

.hero-buttons .btn {
  width: auto;
  min-width: 200px;
}

.btn-sm {
  padding: var(--spacing-2) var(--spacing-3);
  font-size: var(--font-size-xs);
}

.btn-lg {
  padding: var(--spacing-3) var(--spacing-6);
}

/* Forms - Mobile */
.form-group {
  margin-bottom: var(--spacing-3);
}

/* Table - Mobile */
.table-container {
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

.data-table {
  font-size: var(--font-size-xs);
}

.data-table th,
.data-table td {
  padding: var(--spacing-2) var(--spacing-3);
}

/* Cards - Mobile */
.card {
  border-radius: var(--radius-md);
}

/* Modal - Mobile */
.modal {
  width: 95%;
  max-width: 100%;
}

/* Utilities - Mobile */
.flex-between {
  flex-direction: column;
  align-items: flex-start;
}

.gap-6 {
  gap: var(--spacing-4);
}

.gap-8 {
  gap: var(--spacing-4);
}

/* Hide elements on mobile */
.hide-mobile {
  display: none;
}

/* ============================================
   Large Phone: >= 480px
   ============================================ */

@media (min-width: 480px) {
  /* Grid: 2 欄開始 */
  .grid-2 {
    grid-template-columns: repeat(2, 1fr);
  }

  /* Hero buttons: 水平排列 */
  .hero-buttons {
    flex-direction: row;
  }

  .hero-buttons .btn {
    min-width: auto;
  }

  /* Footer: 2 欄 */
  footer .container {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
  }
}

/* ============================================
   Tablet: >= 768px
   ============================================ */

@media (min-width: 768px) {
  /* Typography */
  h1 {
    font-size: var(--font-size-4xl);
  }

  h2 {
    font-size: var(--font-size-3xl);
  }

  h3 {
    font-size: var(--font-size-xl);
  }

  /* Container */
  .container,
  .container-small,
  .container-large {
    padding: 0 var(--spacing-6);
  }

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

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

  /* Navigation */
  .top-nav {
    height: 80px;
  }

  .nav-links {
    display: flex !important;
  }

  .hamburger-menu {
    display: none !important;
  }

  .nav-actions {
    display: flex;
    gap: var(--spacing-2);
  }

  /* 平板版：主題按鈕恢復正常定位 */
  #theme-toggle-btn,
  .mobile-theme-toggle {
    position: static;
    transform: none;
  }

  .nav-actions .btn {
    padding: var(--spacing-2) var(--spacing-4);
    font-size: var(--font-size-base);
  }

  /* Sidebar */
  .sidebar {
    top: 80px;
    width: 200px;
    height: calc(100vh - 80px);
  }

  .sidebar-overlay {
    top: 80px;
  }

  /* Page Layout */
  .page-layout {
    display: grid;
    grid-template-columns: 200px 1fr;
    margin-top: 80px;
  }

  .page-layout main {
    width: auto;
    padding: var(--spacing-6);
  }

  /* Section */
  section {
    padding: var(--spacing-16) 0;
  }

  /* Footer */
  footer .container {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
  }

  footer .container > div {
    margin-bottom: 0;
  }

  /* Utilities */
  .flex-between {
    flex-direction: row;
    align-items: center;
  }

  .gap-6 {
    gap: var(--spacing-6);
  }

  .gap-8 {
    gap: var(--spacing-6);
  }

  /* Hide elements on tablet */
  .hide-tablet {
    display: none;
  }
}

/* ============================================
   Desktop: >= 1024px
   ============================================ */

@media (min-width: 1024px) {
  /* Grid */
  .grid-3 {
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-6);
  }

  .grid-4 {
    grid-template-columns: repeat(4, 1fr);
    gap: var(--spacing-6);
  }

  /* Sidebar - Desktop: 永遠可見 */
  .sidebar {
    left: 0;
    width: 240px;
  }

  .sidebar.dashboard-sidebar {
    display: block;
  }

  /* Page Layout */
  .page-layout {
    grid-template-columns: 240px 1fr;
  }

  .page-layout main {
    padding: var(--spacing-8);
  }

  /* Section */
  section {
    padding: var(--spacing-20) 0;
  }

  section.section-compact {
    padding: var(--spacing-16) 0;
  }

  /* Utilities */
  .gap-8 {
    gap: var(--spacing-8);
  }
}

/* ============================================
   Large Desktop: >= 1280px
   ============================================ */

@media (min-width: 1280px) {
  /* Typography */
  h1 {
    font-size: var(--font-size-6xl);
  }

  h2 {
    font-size: var(--font-size-4xl);
  }

  /* Container */
  .container {
    max-width: 1280px;
  }

  .container-small {
    max-width: 1024px;
  }

  .container-large {
    max-width: 1536px;
  }

  /* Section */
  section {
    padding: var(--spacing-24) 0;
  }

  /* Show elements on desktop only */
  .show-desktop {
    display: block;
  }

  .hide-desktop {
    display: none;
  }
}

/* ============================================
   Extra Large Desktop: >= 1536px
   ============================================ */

@media (min-width: 1536px) {
  .container-large {
    max-width: 1536px;
  }
}

/* ============================================
   Print Styles
   ============================================ */

@media print {
  body {
    background: white;
    color: black;
  }

  .no-print {
    display: none;
  }

  a {
    color: black;
    text-decoration: underline;
  }
}

/* ============================================
   High DPI / Retina Displays
   ============================================ */

@media (-webkit-min-device-pixel-ratio: 2), (min-resolution: 192dpi) {
  .card {
    border-width: 1px;
  }
}

/* ============================================
   Landscape Mode (Mobile)
   ============================================ */

@media (max-height: 500px) and (orientation: landscape) {
  section {
    padding: var(--spacing-8) 0;
  }

  .container {
    padding: 0 var(--spacing-4);
  }

  h1 {
    font-size: var(--font-size-2xl);
  }

  h2 {
    font-size: var(--font-size-xl);
  }
}

/* ============================================
   Reduced Motion (Accessibility)
   ============================================ */

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

/* ============================================
   Dark Mode (System Preference)
   ============================================ */

@media (prefers-color-scheme: dark) {
  body {
    background-color: var(--color-bg-primary);
    color: var(--color-text-primary);
  }
}