/* ============================================================
   CSS Custom Properties (Material Design 3 inspired)
   ============================================================ */
:root {
  --md-primary: #006B5E;
  --md-primary-dark: #004D43;
  --md-primary-light: #00897B;
  --md-on-primary: #ffffff;
  --md-primary-container: #A7F3E5;
  --md-on-primary-container: #002019;

  --md-secondary: #4A6360;
  --md-on-secondary: #ffffff;
  --md-secondary-container: #CCE8E3;
  --md-on-secondary-container: #051F1D;

  --md-error: #BA1A1A;
  --md-on-error: #ffffff;
  --md-error-container: #FFDAD6;
  --md-on-error-container: #410002;

  --md-background: #F5FAFA;
  --md-on-background: #191C1C;
  --md-surface: #F5FAFA;
  --md-on-surface: #191C1C;
  --md-surface-variant: #DAE5E3;
  --md-on-surface-variant: #3F4947;
  --md-outline: #6F7978;
  --md-outline-variant: #BEC9C7;

  --md-shadow: rgba(0, 0, 0, 0.15);
  --md-scrim: rgba(0, 0, 0, 0.32);

  --md-surface-1: #EBF4F3;
  --md-surface-2: #E0EEF0;
  --md-surface-3: #D5E9EA;
  --md-surface-4: #CEE6E8;

  /* Elevation */
  --elevation-1: 0 1px 2px rgba(0,0,0,0.1), 0 1px 3px 1px rgba(0,0,0,0.05);
  --elevation-2: 0 1px 2px rgba(0,0,0,0.1), 0 2px 6px 2px rgba(0,0,0,0.05);
  --elevation-3: 0 4px 8px 3px rgba(0,0,0,0.07), 0 1px 3px rgba(0,0,0,0.1);

  /* Typography */
  --font-sans: 'Noto Sans JP', 'Roboto', sans-serif;

  /* Border Radius */
  --radius-xs: 4px;
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 28px;
  --radius-full: 50px;

  /* Spacing */
  --sp-1: 4px;
  --sp-2: 8px;
  --sp-3: 12px;
  --sp-4: 16px;
  --sp-5: 20px;
  --sp-6: 24px;
  --sp-8: 32px;
  --sp-10: 40px;
  --sp-12: 48px;

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-base: 250ms ease;
  --transition-slow: 350ms ease;

  /* Z-index */
  --z-drawer: 200;
  --z-modal: 300;
  --z-toast: 400;
  --z-loading: 500;
}

/* ============================================================
   Reset CSS
   ============================================================ */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans);
  background-color: var(--md-background);
  color: var(--md-on-background);
  line-height: 1.6;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

a {
  color: var(--md-primary);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

button {
  font-family: var(--font-sans);
  cursor: pointer;
  border: none;
  background: none;
}

input, textarea, select {
  font-family: var(--font-sans);
}

ul, ol {
  list-style: none;
}

/* ============================================================
   Typography
   ============================================================ */
.display-large {
  font-size: 57px;
  font-weight: 400;
  line-height: 64px;
  letter-spacing: -0.25px;
}

.display-medium {
  font-size: 45px;
  font-weight: 400;
  line-height: 52px;
}

.headline-large {
  font-size: 32px;
  font-weight: 400;
  line-height: 40px;
}

.headline-medium {
  font-size: 28px;
  font-weight: 400;
  line-height: 36px;
}

.headline-small {
  font-size: 24px;
  font-weight: 400;
  line-height: 32px;
}

.title-large {
  font-size: 22px;
  font-weight: 500;
  line-height: 28px;
}

.title-medium {
  font-size: 16px;
  font-weight: 500;
  line-height: 24px;
  letter-spacing: 0.15px;
}

.title-small {
  font-size: 14px;
  font-weight: 500;
  line-height: 20px;
  letter-spacing: 0.1px;
}

.body-large {
  font-size: 16px;
  font-weight: 400;
  line-height: 24px;
  letter-spacing: 0.5px;
}

.body-medium {
  font-size: 14px;
  font-weight: 400;
  line-height: 20px;
  letter-spacing: 0.25px;
}

.body-small {
  font-size: 12px;
  font-weight: 400;
  line-height: 16px;
  letter-spacing: 0.4px;
}

.label-large {
  font-size: 14px;
  font-weight: 500;
  line-height: 20px;
  letter-spacing: 0.1px;
}

.label-medium {
  font-size: 12px;
  font-weight: 500;
  line-height: 16px;
  letter-spacing: 0.5px;
}

/* ============================================================
   Card Component
   ============================================================ */
.card {
  background: var(--md-surface);
  border-radius: var(--radius-md);
  box-shadow: var(--elevation-1);
  padding: var(--sp-6);
  transition: box-shadow var(--transition-base);
}

.card:hover {
  box-shadow: var(--elevation-2);
}

.card--elevated {
  box-shadow: var(--elevation-2);
}

.card--filled {
  background: var(--md-surface-1);
  box-shadow: none;
}

.card--outlined {
  background: var(--md-surface);
  box-shadow: none;
  border: 1px solid var(--md-outline-variant);
}

.card__header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--sp-4);
}

.card__title {
  font-size: 18px;
  font-weight: 500;
  color: var(--md-on-surface);
}

.card__subtitle {
  font-size: 13px;
  color: var(--md-on-surface-variant);
  margin-top: var(--sp-1);
}

/* ============================================================
   Buttons
   ============================================================ */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--sp-2);
  padding: 10px 24px;
  border-radius: var(--radius-full);
  font-size: 14px;
  font-weight: 500;
  line-height: 20px;
  letter-spacing: 0.1px;
  transition: all var(--transition-fast);
  cursor: pointer;
  border: none;
  text-decoration: none;
  white-space: nowrap;
  position: relative;
  overflow: hidden;
  outline: none;
}

.btn:focus-visible {
  outline: 3px solid var(--md-primary);
  outline-offset: 2px;
}

.btn:disabled {
  opacity: 0.38;
  cursor: not-allowed;
  pointer-events: none;
}

.btn .material-icons {
  font-size: 18px;
}

/* Filled Button */
.btn-filled {
  background: var(--md-primary);
  color: var(--md-on-primary);
  box-shadow: var(--elevation-1);
}

.btn-filled:hover {
  background: var(--md-primary-light);
  box-shadow: var(--elevation-2);
}

.btn-filled:active {
  background: var(--md-primary-dark);
  box-shadow: none;
}

/* Outlined Button */
.btn-outlined {
  background: transparent;
  color: var(--md-primary);
  border: 1px solid var(--md-outline);
}

.btn-outlined:hover {
  background: rgba(0, 107, 94, 0.08);
  border-color: var(--md-primary);
}

.btn-outlined:active {
  background: rgba(0, 107, 94, 0.12);
}

/* Text Button */
.btn-text {
  background: transparent;
  color: var(--md-primary);
  padding: 10px 12px;
}

.btn-text:hover {
  background: rgba(0, 107, 94, 0.08);
}

.btn-text:active {
  background: rgba(0, 107, 94, 0.12);
}

/* Tonal Button */
.btn-tonal {
  background: var(--md-secondary-container);
  color: var(--md-on-secondary-container);
}

.btn-tonal:hover {
  background: var(--md-primary-container);
  color: var(--md-on-primary-container);
  box-shadow: var(--elevation-1);
}

/* Danger Button */
.btn-danger {
  background: var(--md-error);
  color: var(--md-on-error);
}

.btn-danger:hover {
  background: #D32F2F;
  box-shadow: var(--elevation-2);
}

/* Icon Button */
.btn-icon {
  width: 40px;
  height: 40px;
  padding: 0;
  border-radius: 50%;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: var(--md-on-surface-variant);
  background: transparent;
}

.btn-icon:hover {
  background: rgba(0, 0, 0, 0.08);
}

.btn-icon .material-icons {
  font-size: 20px;
}

/* Reorder Buttons */
.reorder-btns {
  display: flex;
  flex-direction: column;
  align-items: center;
  flex-shrink: 0;
}

.reorder-btn {
  width: 28px !important;
  height: 22px !important;
  min-width: 0 !important;
  padding: 0 !important;
  color: var(--md-on-surface-variant);
  border-radius: var(--radius-xs, 4px);
  transition: background 0.15s, color 0.15s;
}

.reorder-btn:hover {
  background: var(--md-primary-container) !important;
  color: var(--md-primary) !important;
}

.reorder-btn:active {
  background: var(--md-primary) !important;
  color: var(--md-on-primary) !important;
}

/* FAB */
.fab {
  display: inline-flex;
  align-items: center;
  gap: var(--sp-2);
  padding: 16px;
  border-radius: var(--radius-lg);
  background: var(--md-primary-container);
  color: var(--md-on-primary-container);
  box-shadow: var(--elevation-3);
  cursor: pointer;
  border: none;
  font-weight: 500;
  transition: all var(--transition-base);
}

.fab:hover {
  box-shadow: var(--elevation-3);
  background: var(--md-primary);
  color: var(--md-on-primary);
}

/* ============================================================
   Text Field Component
   ============================================================ */
.text-field {
  display: flex;
  flex-direction: column;
  gap: var(--sp-1);
}

.text-field__label {
  font-size: 12px;
  font-weight: 500;
  color: var(--md-on-surface-variant);
  letter-spacing: 0.4px;
}

.text-field__container {
  position: relative;
  display: flex;
  align-items: center;
  background: var(--md-surface-variant);
  border-radius: var(--radius-xs) var(--radius-xs) 0 0;
  border-bottom: 2px solid var(--md-outline);
  transition: border-color var(--transition-fast);
}

.text-field__container:focus-within {
  border-bottom-color: var(--md-primary);
}

.text-field__container:focus-within .text-field__label {
  color: var(--md-primary);
}

.text-field input,
.text-field textarea,
.text-field select {
  flex: 1;
  padding: var(--sp-4) var(--sp-4);
  background: transparent;
  border: none;
  outline: none;
  font-size: 16px;
  color: var(--md-on-surface);
  width: 100%;
}

.text-field textarea {
  resize: vertical;
  min-height: 100px;
}

.text-field__icon {
  padding: 0 var(--sp-3);
  color: var(--md-on-surface-variant);
}

.text-field__error {
  font-size: 12px;
  color: var(--md-error);
  padding: 0 var(--sp-4);
}

/* Outlined variant */
.text-field--outlined .text-field__container {
  background: var(--md-surface);
  border: 1px solid var(--md-outline);
  border-radius: var(--radius-xs);
}

.text-field--outlined .text-field__container:focus-within {
  border-color: var(--md-primary);
  border-width: 2px;
}

/* Floating label style */
.field-group {
  display: flex;
  flex-direction: column;
  gap: var(--sp-2);
  margin-bottom: var(--sp-5);
}

.field-group label {
  font-size: 14px;
  font-weight: 500;
  color: var(--md-on-surface-variant);
}

.field-group input,
.field-group textarea,
.field-group select {
  padding: var(--sp-3) var(--sp-4);
  border: 1px solid var(--md-outline-variant);
  border-radius: var(--radius-sm);
  font-size: 16px;
  color: var(--md-on-surface);
  background: var(--md-surface);
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
  outline: none;
  width: 100%;
}

.field-group input:focus,
.field-group textarea:focus,
.field-group select:focus {
  border-color: var(--md-primary);
  box-shadow: 0 0 0 3px rgba(0, 107, 94, 0.15);
}

.field-group input::placeholder,
.field-group textarea::placeholder {
  color: var(--md-outline);
}

.field-group textarea {
  resize: vertical;
  min-height: 80px;
}

/* ============================================================
   Chip Component
   ============================================================ */
.chip {
  display: inline-flex;
  align-items: center;
  gap: var(--sp-1);
  padding: 6px 16px;
  border-radius: var(--radius-full);
  font-size: 14px;
  font-weight: 500;
  cursor: pointer;
  border: 1px solid var(--md-outline-variant);
  background: var(--md-surface);
  color: var(--md-on-surface-variant);
  transition: all var(--transition-fast);
  white-space: nowrap;
}

.chip:hover {
  background: var(--md-surface-1);
  border-color: var(--md-outline);
}

.chip--selected {
  background: var(--md-secondary-container);
  color: var(--md-on-secondary-container);
  border-color: transparent;
}

.chip--selected:hover {
  background: var(--md-primary-container);
  color: var(--md-on-primary-container);
}

.chip .material-icons {
  font-size: 16px;
}

.chip-group {
  display: flex;
  flex-wrap: wrap;
  gap: var(--sp-2);
}

/* ============================================================
   Top App Bar
   ============================================================ */
.top-app-bar {
  position: sticky;
  top: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  padding: 0 var(--sp-4);
  height: 64px;
  background: var(--md-primary);
  color: var(--md-on-primary);
  box-shadow: var(--elevation-2);
  gap: var(--sp-3);
}

.top-app-bar__logo {
  display: flex;
  align-items: center;
  gap: var(--sp-2);
  font-size: 20px;
  font-weight: 700;
  color: var(--md-on-primary);
  text-decoration: none;
}

.top-app-bar__logo .material-icons {
  font-size: 28px;
}

.top-app-bar__title {
  flex: 1;
  font-size: 20px;
  font-weight: 500;
  color: var(--md-on-primary);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.top-app-bar__actions {
  display: flex;
  align-items: center;
  gap: var(--sp-1);
  margin-left: auto;
}

.top-app-bar .btn-icon {
  color: var(--md-on-primary);
}

.top-app-bar .btn-icon:hover {
  background: rgba(255, 255, 255, 0.15);
}

/* ============================================================
   Navigation Drawer
   ============================================================ */
.nav-drawer {
  position: fixed;
  top: 0;
  left: -280px;
  width: 280px;
  height: 100vh;
  background: var(--md-surface);
  z-index: var(--z-drawer);
  box-shadow: var(--elevation-3);
  transition: left var(--transition-base);
  display: flex;
  flex-direction: column;
  overflow-y: auto;
}

.nav-drawer--open {
  left: 0;
}

.nav-drawer__header {
  padding: var(--sp-6) var(--sp-4) var(--sp-4);
  background: var(--md-primary);
  color: var(--md-on-primary);
}

.nav-drawer__header-title {
  font-size: 18px;
  font-weight: 700;
}

.nav-drawer__header-subtitle {
  font-size: 13px;
  opacity: 0.8;
  margin-top: var(--sp-1);
}

.nav-drawer__section-title {
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 1px;
  text-transform: uppercase;
  color: var(--md-on-surface-variant);
  padding: var(--sp-4) var(--sp-4) var(--sp-2);
}

.nav-item {
  display: flex;
  align-items: center;
  gap: var(--sp-3);
  padding: var(--sp-3) var(--sp-4);
  border-radius: var(--radius-full);
  margin: 2px var(--sp-2);
  cursor: pointer;
  color: var(--md-on-surface-variant);
  font-size: 14px;
  font-weight: 500;
  transition: background var(--transition-fast);
  border: none;
  background: none;
  width: calc(100% - 16px);
  text-align: left;
}

.nav-item:hover {
  background: var(--md-surface-1);
  color: var(--md-on-surface);
}

.nav-item--active {
  background: var(--md-secondary-container);
  color: var(--md-on-secondary-container);
}

.nav-item .material-icons {
  font-size: 22px;
}

.nav-overlay {
  position: fixed;
  inset: 0;
  background: var(--md-scrim);
  z-index: calc(var(--z-drawer) - 1);
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition-base);
}

.nav-overlay--visible {
  opacity: 1;
  pointer-events: all;
}

/* ============================================================
   Loading Spinner
   ============================================================ */
.loading-overlay {
  position: fixed;
  inset: 0;
  background: rgba(245, 250, 250, 0.85);
  z-index: var(--z-loading);
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition-base);
}

.loading-overlay--visible {
  opacity: 1;
  pointer-events: all;
}

.spinner {
  width: 48px;
  height: 48px;
  border: 4px solid var(--md-outline-variant);
  border-top-color: var(--md-primary);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

/* ============================================================
   Toast Notification
   ============================================================ */
.toast-container {
  position: fixed;
  bottom: var(--sp-6);
  left: 50%;
  transform: translateX(-50%);
  z-index: var(--z-toast);
  display: flex;
  flex-direction: column;
  gap: var(--sp-2);
  align-items: center;
  pointer-events: none;
}

.toast {
  display: inline-flex;
  align-items: center;
  gap: var(--sp-2);
  padding: var(--sp-3) var(--sp-5);
  border-radius: var(--radius-sm);
  background: #333;
  color: #fff;
  font-size: 14px;
  font-weight: 500;
  box-shadow: var(--elevation-3);
  max-width: min(480px, calc(100vw - 32px));
  pointer-events: all;
  animation: slideUp 0.3s ease, fadeOut 0.3s ease 2.7s forwards;
}

.toast--success {
  background: #1B5E20;
}

.toast--error {
  background: var(--md-error);
}

.toast--warning {
  background: #E65100;
}

.toast--info {
  background: #0D47A1;
}

.toast .material-icons {
  font-size: 18px;
}

@keyframes slideUp {
  from { transform: translateY(20px); opacity: 0; }
  to { transform: translateY(0); opacity: 1; }
}

@keyframes fadeOut {
  from { opacity: 1; }
  to { opacity: 0; }
}

/* ============================================================
   Layout
   ============================================================ */
.layout {
  display: flex;
  min-height: calc(100vh - 64px);
}

.layout__sidebar {
  width: 280px;
  flex-shrink: 0;
  background: var(--md-surface);
  border-right: 1px solid var(--md-outline-variant);
  padding: var(--sp-4) 0;
  position: sticky;
  top: 64px;
  height: calc(100vh - 64px);
  overflow-y: auto;
}

.layout__main {
  flex: 1;
  padding: var(--sp-6);
  max-width: 1200px;
  width: 100%;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--sp-6);
}

/* ============================================================
   Side Panel
   ============================================================ */
.side-panel {
  position: fixed;
  top: 64px;
  right: -420px;
  width: 420px;
  height: calc(100vh - 64px);
  background: var(--md-surface);
  border-left: 1px solid var(--md-outline-variant);
  z-index: var(--z-drawer);
  box-shadow: var(--elevation-3);
  transition: right var(--transition-base);
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

.side-panel--open {
  right: 0;
}

.side-panel__header {
  padding: var(--sp-4) var(--sp-5);
  border-bottom: 1px solid var(--md-outline-variant);
  display: flex;
  align-items: center;
  gap: var(--sp-3);
  background: var(--md-surface-1);
}

.side-panel__title {
  flex: 1;
  font-size: 18px;
  font-weight: 500;
}

.side-panel__content {
  flex: 1;
  overflow-y: auto;
  padding: var(--sp-4);
}

/* ============================================================
   iFrame Container
   ============================================================ */
.iframe-container {
  position: relative;
  width: 100%;
  border-radius: var(--radius-md);
  overflow: hidden;
  background: var(--md-surface-variant);
  border: 1px solid var(--md-outline-variant);
}

.iframe-container iframe {
  width: 100%;
  border: none;
  display: block;
}

.iframe-container--doc {
  padding-bottom: 129.4%; /* A4 ratio */
}

.iframe-container--slide {
  padding-bottom: 56.25%; /* 16:9 */
}

.iframe-container--doc iframe,
.iframe-container--slide iframe {
  position: absolute;
  top: 0;
  left: 0;
  height: 100%;
}

.iframe-placeholder {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: var(--sp-3);
  padding: var(--sp-10);
  color: var(--md-on-surface-variant);
}

.iframe-placeholder .material-icons {
  font-size: 48px;
  opacity: 0.5;
}

/* ============================================================
   Status Badge
   ============================================================ */
.badge {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 3px 10px;
  border-radius: var(--radius-full);
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.3px;
}

.badge--draft {
  background: var(--md-surface-variant);
  color: var(--md-on-surface-variant);
}

.badge--published {
  background: #E8F5E9;
  color: #1B5E20;
}

.badge--archived {
  background: #FFF3E0;
  color: #E65100;
}

/* ============================================================
   Table
   ============================================================ */
.table-container {
  overflow-x: auto;
  border-radius: var(--radius-md);
  border: 1px solid var(--md-outline-variant);
}

table {
  width: 100%;
  border-collapse: collapse;
}

thead {
  background: var(--md-surface-1);
}

thead th {
  padding: var(--sp-3) var(--sp-4);
  text-align: left;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.5px;
  text-transform: uppercase;
  color: var(--md-on-surface-variant);
  white-space: nowrap;
  border-bottom: 1px solid var(--md-outline-variant);
}

tbody tr {
  border-bottom: 1px solid var(--md-outline-variant);
  transition: background var(--transition-fast);
}

tbody tr:last-child {
  border-bottom: none;
}

tbody tr:hover {
  background: var(--md-surface-1);
}

tbody td {
  padding: var(--sp-3) var(--sp-4);
  font-size: 14px;
  color: var(--md-on-surface);
  vertical-align: middle;
}

/* ============================================================
   Tabs
   ============================================================ */
.tabs {
  display: flex;
  border-bottom: 1px solid var(--md-outline-variant);
  overflow-x: auto;
}

.tab {
  display: inline-flex;
  align-items: center;
  gap: var(--sp-2);
  padding: var(--sp-3) var(--sp-5);
  font-size: 14px;
  font-weight: 500;
  color: var(--md-on-surface-variant);
  cursor: pointer;
  border-bottom: 2px solid transparent;
  white-space: nowrap;
  transition: all var(--transition-fast);
  border: none;
  background: none;
}

.tab:hover {
  color: var(--md-primary);
  background: rgba(0, 107, 94, 0.05);
}

.tab--active {
  color: var(--md-primary);
  border-bottom-color: var(--md-primary);
}

.tab-panel {
  display: none;
  padding: var(--sp-6) 0;
}

.tab-panel--active {
  display: block;
}

/* ============================================================
   Accordion
   ============================================================ */
.accordion {
  border-radius: var(--radius-md);
  overflow: hidden;
  border: 1px solid var(--md-outline-variant);
}

.accordion-item {
  border-bottom: 1px solid var(--md-outline-variant);
}

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

.accordion-header {
  display: flex;
  align-items: center;
  touch-action: manipulation;
  -webkit-tap-highlight-color: rgba(0,0,0,0.05);
  user-select: none;
  -webkit-user-select: none;
  gap: var(--sp-3);
  padding: var(--sp-4) var(--sp-5);
  cursor: pointer;
  background: var(--md-surface);
  transition: background var(--transition-fast);
  border: none;
  width: 100%;
  text-align: left;
}

.accordion-header:hover {
  background: var(--md-surface-1);
}

.accordion-header--open {
  background: var(--md-surface-1);
}

.accordion-title {
  flex: 1;
  font-size: 16px;
  font-weight: 500;
  color: var(--md-on-surface);
}

.accordion-icon {
  color: var(--md-on-surface-variant);
  transition: transform var(--transition-fast);
}

.accordion-header--open .accordion-icon {
  transform: rotate(180deg);
}

.accordion-body {
  display: none;
  padding: var(--sp-4) var(--sp-5);
  background: var(--md-surface);
  border-top: 1px solid var(--md-outline-variant);
}

.accordion-body--open {
  display: block;
}

/* ============================================================
   Material Card (for seminar materials)
   ============================================================ */
.material-card {
  display: flex;
  align-items: flex-start;
  gap: var(--sp-3);
  padding: var(--sp-4);
  background: var(--md-surface);
  border: 1px solid var(--md-outline-variant);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
  cursor: pointer;
  margin-bottom: var(--sp-3);
  /* Mobile tap improvements */
  touch-action: manipulation;
  -webkit-tap-highlight-color: rgba(0,0,0,0.05);
  user-select: none;
  -webkit-user-select: none;
}

.material-card:hover {
  background: var(--md-surface-1);
  border-color: var(--md-primary);
  box-shadow: var(--elevation-1);
}

.material-card--active {
  background: var(--md-primary-container);
  border-color: var(--md-primary);
}

.material-card__icon {
  width: 40px;
  height: 40px;
  border-radius: var(--radius-sm);
  background: var(--md-primary-container);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.material-card__icon .material-icons {
  color: var(--md-primary);
  font-size: 22px;
}

.material-card__content {
  flex: 1;
  min-width: 0;
}

.material-card__title {
  font-size: 15px;
  font-weight: 500;
  color: var(--md-on-surface);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.material-card__desc {
  font-size: 12px;
  color: var(--md-on-surface-variant);
  margin-top: var(--sp-1);
}

.material-card__actions {
  display: flex;
  gap: var(--sp-1);
  flex-shrink: 0;
}

/* ============================================================
   Login Form
   ============================================================ */
.login-page {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--sp-6);
  background: linear-gradient(135deg, var(--md-primary) 0%, var(--md-primary-light) 100%);
}

.login-card {
  width: 100%;
  max-width: 420px;
  background: var(--md-surface);
  border-radius: var(--radius-lg);
  box-shadow: var(--elevation-3);
  padding: var(--sp-8);
}

.login-logo {
  display: flex;
  align-items: center;
  gap: var(--sp-2);
  justify-content: center;
  margin-bottom: var(--sp-6);
}

.login-logo .material-icons {
  font-size: 40px;
  color: var(--md-primary);
}

.login-logo-text {
  font-size: 22px;
  font-weight: 700;
  color: var(--md-primary);
}

.login-title {
  font-size: 24px;
  font-weight: 700;
  color: var(--md-on-surface);
  text-align: center;
  margin-bottom: var(--sp-2);
}

.login-subtitle {
  font-size: 14px;
  color: var(--md-on-surface-variant);
  text-align: center;
  margin-bottom: var(--sp-6);
}

/* ============================================================
   Admin Layout
   ============================================================ */
.admin-layout {
  display: flex;
  min-height: calc(100vh - 64px);
}

.admin-sidebar {
  width: 260px;
  flex-shrink: 0;
  background: var(--md-surface);
  border-right: 1px solid var(--md-outline-variant);
  padding: var(--sp-4) 0;
  position: sticky;
  top: 64px;
  height: calc(100vh - 64px);
  overflow-y: auto;
}

.admin-main {
  flex: 1;
  padding: var(--sp-6);
  overflow-x: hidden;
}

/* ============================================================
   Seminar Header (Participant View)
   ============================================================ */
.seminar-header {
  background: linear-gradient(135deg, var(--md-primary) 0%, var(--md-primary-light) 100%);
  color: var(--md-on-primary);
  padding: var(--sp-8) var(--sp-6);
  border-radius: 0 0 var(--radius-xl) var(--radius-xl);
  margin-bottom: var(--sp-6);
}

.seminar-header__category {
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 1px;
  text-transform: uppercase;
  opacity: 0.8;
  margin-bottom: var(--sp-2);
}

.seminar-header__title {
  font-size: 28px;
  font-weight: 700;
  line-height: 1.3;
  margin-bottom: var(--sp-4);
}

.seminar-header__meta {
  display: flex;
  flex-wrap: wrap;
  gap: var(--sp-4);
}

.seminar-header__meta-item {
  display: flex;
  align-items: center;
  gap: var(--sp-1);
  font-size: 14px;
  opacity: 0.9;
}

.seminar-header__meta-item .material-icons {
  font-size: 16px;
}

/* ============================================================
   Page Header
   ============================================================ */
.page-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--sp-6);
  flex-wrap: wrap;
  gap: var(--sp-4);
}

.page-header__title {
  font-size: 24px;
  font-weight: 700;
  color: var(--md-on-surface);
}

.page-header__subtitle {
  font-size: 14px;
  color: var(--md-on-surface-variant);
  margin-top: var(--sp-1);
}

/* ============================================================
   Search Bar
   ============================================================ */
.search-bar {
  display: flex;
  align-items: center;
  background: var(--md-surface-variant);
  border-radius: var(--radius-full);
  padding: var(--sp-2) var(--sp-4);
  gap: var(--sp-2);
  max-width: 400px;
}

.search-bar input {
  flex: 1;
  border: none;
  background: transparent;
  outline: none;
  font-size: 14px;
  color: var(--md-on-surface);
}

.search-bar .material-icons {
  color: var(--md-on-surface-variant);
  font-size: 20px;
}

/* ============================================================
   Access Denied Page
   ============================================================ */
.access-denied {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--sp-6);
  background: var(--md-background);
}

.access-denied__card {
  text-align: center;
  max-width: 480px;
  width: 100%;
}

.access-denied__icon {
  font-size: 80px;
  margin-bottom: var(--sp-4);
}

.access-denied__title {
  font-size: 26px;
  font-weight: 700;
  color: var(--md-on-surface);
  margin-bottom: var(--sp-2);
}

.access-denied__message {
  font-size: 16px;
  color: var(--md-on-surface-variant);
  line-height: 1.7;
  margin-bottom: var(--sp-6);
}

.access-denied__date {
  display: inline-flex;
  align-items: center;
  gap: var(--sp-2);
  padding: var(--sp-3) var(--sp-5);
  background: var(--md-surface-1);
  border-radius: var(--radius-md);
  font-size: 14px;
  font-weight: 500;
  color: var(--md-on-surface);
  margin-bottom: var(--sp-4);
}

/* ============================================================
   QR Code Section
   ============================================================ */
.qr-section {
  text-align: center;
  padding: var(--sp-6);
  background: var(--md-surface-1);
  border-radius: var(--radius-md);
}

.qr-section img {
  display: inline-block;
  border: 8px solid #fff;
  border-radius: var(--radius-sm);
  box-shadow: var(--elevation-1);
}

/* ============================================================
   Empty State
   ============================================================ */
.empty-state {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: var(--sp-12) var(--sp-6);
  text-align: center;
  color: var(--md-on-surface-variant);
}

.empty-state .material-icons {
  font-size: 64px;
  opacity: 0.4;
  margin-bottom: var(--sp-4);
}

.empty-state__title {
  font-size: 18px;
  font-weight: 500;
  color: var(--md-on-surface);
  margin-bottom: var(--sp-2);
}

.empty-state__message {
  font-size: 14px;
  margin-bottom: var(--sp-6);
}

/* ============================================================
   Divider
   ============================================================ */
.divider {
  height: 1px;
  background: var(--md-outline-variant);
  margin: var(--sp-4) 0;
}

/* ============================================================
   Utility Classes
   ============================================================ */
.flex { display: flex; }
.flex-col { flex-direction: column; }
.items-center { align-items: center; }
.justify-between { justify-content: space-between; }
.justify-center { justify-content: center; }
.gap-2 { gap: var(--sp-2); }
.gap-3 { gap: var(--sp-3); }
.gap-4 { gap: var(--sp-4); }
.gap-6 { gap: var(--sp-6); }
.flex-1 { flex: 1; }
.w-full { width: 100%; }
.text-center { text-align: center; }
.text-sm { font-size: 14px; }
.text-xs { font-size: 12px; }
.font-bold { font-weight: 700; }
.font-medium { font-weight: 500; }
.mt-2 { margin-top: var(--sp-2); }
.mt-4 { margin-top: var(--sp-4); }
.mt-6 { margin-top: var(--sp-6); }
.mb-2 { margin-bottom: var(--sp-2); }
.mb-4 { margin-bottom: var(--sp-4); }
.mb-6 { margin-bottom: var(--sp-6); }
.p-4 { padding: var(--sp-4); }
.p-6 { padding: var(--sp-6); }
.hidden { display: none !important; }

.text-primary { color: var(--md-primary); }
.text-error { color: var(--md-error); }
.text-muted { color: var(--md-on-surface-variant); }

/* ============================================================
   Nav overlay (mobile sidebar backdrop)
   ============================================================ */
.nav-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: var(--md-scrim);
  z-index: calc(var(--z-drawer) - 1);
}

.nav-overlay--visible {
  display: block;
}

/* ============================================================
   Hamburger button: hide on desktop, show on mobile
   ============================================================ */
.nav-toggle-btn {
  display: none;
}

/* ============================================================
   Table: always horizontally scrollable
   ============================================================ */
.table-container {
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  border-radius: var(--radius-md);
}

/* ============================================================
   Chip group: wrap properly on small screens
   ============================================================ */
.chip-group {
  display: flex;
  flex-wrap: wrap;
  gap: var(--sp-2);
}

/* ============================================================
   Responsive (Mobile First)
   ============================================================ */
@media (max-width: 768px) {
  /* Hamburger visible on mobile */
  .nav-toggle-btn {
    display: flex;
  }

  /* Sidebar becomes a fixed drawer on mobile */
  .admin-sidebar {
    position: fixed;
    top: 0;
    left: -280px;
    height: 100vh;
    width: 280px;
    z-index: var(--z-drawer);
    box-shadow: var(--elevation-3);
    transition: left var(--transition-base);
    padding-top: var(--sp-12);
  }

  .admin-sidebar--open {
    left: 0;
  }

  .admin-main {
    padding: var(--sp-4);
    min-width: 0;
  }

  .seminar-header {
    padding: var(--sp-5) var(--sp-4);
    border-radius: 0 0 var(--radius-lg) var(--radius-lg);
  }

  .seminar-header__title {
    font-size: 22px;
  }

  .side-panel {
    width: 100%;
    right: -100%;
    top: 0;
    height: 100vh;
  }

  .side-panel--open {
    right: 0;
  }

  .page-header {
    flex-direction: column;
    align-items: flex-start;
  }

  .login-card {
    padding: var(--sp-6);
  }

  .top-app-bar__title {
    font-size: 16px;
  }

  table {
    font-size: 13px;
    min-width: 560px; /* force horizontal scroll on small screens */
  }

  tbody td, thead th {
    padding: var(--sp-2) var(--sp-3);
  }

  /* Admin tab list wraps on mobile */
  .tab-list {
    flex-wrap: wrap;
  }

  /* Filter row stacks on small screens */
  .filter-row {
    flex-direction: column;
  }

  /* Login card full width */
  .login-card {
    max-width: 100%;
    border-radius: var(--radius-md);
  }
}

@media (min-width: 769px) {
  .nav-overlay {
    display: none !important;
  }

  .nav-drawer {
    left: 0;
    box-shadow: none;
    border-right: 1px solid var(--md-outline-variant);
  }
}

/* Medium screens: compact sidebar */
@media (min-width: 769px) and (max-width: 1024px) {
  .admin-sidebar {
    width: 200px;
  }

  .admin-main {
    padding: var(--sp-4) var(--sp-5);
  }
}

/* ============================================================
   Seminar List (Participant Top Page)
   ============================================================ */
.sl-root {
  min-height: 100vh;
  background: var(--md-background);
}

/* Header */
.sl-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--md-primary);
  color: var(--md-on-primary);
  box-shadow: var(--elevation-2);
}
.sl-header-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--sp-5);
  height: 60px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.sl-logo {
  display: flex;
  align-items: center;
  gap: var(--sp-2);
  font-size: 18px;
  font-weight: 700;
  letter-spacing: -0.3px;
}
.sl-logo .material-icons { font-size: 24px; }
.sl-admin-link {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 13px;
  color: rgba(255,255,255,0.8);
  text-decoration: none;
  padding: 6px 12px;
  border-radius: var(--radius-full);
  transition: background var(--transition-fast);
}
.sl-admin-link:hover {
  background: rgba(255,255,255,0.12);
  color: #fff;
}
.sl-admin-link .material-icons { font-size: 18px; }

/* Hero */
.sl-hero {
  background: linear-gradient(160deg, var(--md-primary) 0%, var(--md-primary-light) 100%);
  color: var(--md-on-primary);
  padding: 48px var(--sp-5) 36px;
  text-align: center;
}
.sl-hero-title {
  font-size: 28px;
  font-weight: 700;
  margin: 0 0 var(--sp-2);
  letter-spacing: -0.5px;
}
.sl-hero-subtitle {
  font-size: 15px;
  opacity: 0.85;
  margin: 0 0 var(--sp-6);
}

/* Search */
.sl-search-wrap {
  position: relative;
  max-width: 520px;
  margin: 0 auto;
}
.sl-search-icon {
  position: absolute;
  left: 16px;
  top: 50%;
  transform: translateY(-50%);
  color: var(--md-on-surface-variant);
  font-size: 20px;
  pointer-events: none;
}
.sl-search-input {
  width: 100%;
  padding: 14px 16px 14px 48px;
  border: none;
  border-radius: var(--radius-xl);
  font-size: 15px;
  font-family: var(--font-sans);
  background: #fff;
  color: var(--md-on-surface);
  box-shadow: var(--elevation-2);
  outline: none;
  box-sizing: border-box;
  transition: box-shadow var(--transition-fast);
}
.sl-search-input:focus {
  box-shadow: var(--elevation-3);
}

/* Filter chips */
.sl-filters {
  display: flex;
  flex-wrap: wrap;
  gap: var(--sp-2);
  max-width: 1200px;
  margin: 20px auto 0;
  padding: 0 var(--sp-5);
}
.sl-chip {
  padding: 8px 16px;
  border-radius: var(--radius-full);
  font-size: 13px;
  font-weight: 500;
  cursor: pointer;
  border: 1.5px solid var(--md-outline-variant);
  background: var(--md-surface);
  color: var(--md-on-surface-variant);
  transition: all var(--transition-fast);
  white-space: nowrap;
  font-family: var(--font-sans);
}
.sl-chip:hover {
  background: var(--md-surface-1);
  border-color: var(--md-outline);
}
.sl-chip--active {
  background: var(--md-primary);
  color: var(--md-on-primary);
  border-color: transparent;
}
.sl-chip--active:hover {
  background: var(--md-primary-dark);
}

/* Content */
.sl-content {
  max-width: 1200px;
  margin: 24px auto 48px;
  padding: 0 var(--sp-5);
}

/* Grid */
.sl-grid-inner {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}

/* Card */
.sl-card {
  background: var(--md-surface);
  border-radius: var(--radius-lg);
  padding: 20px;
  box-shadow: var(--elevation-1);
  cursor: pointer;
  transition: box-shadow var(--transition-fast), transform var(--transition-fast);
  display: flex;
  flex-direction: column;
  gap: 10px;
  border: 1px solid var(--md-outline-variant);
}
.sl-card:hover {
  box-shadow: var(--elevation-3);
  transform: translateY(-2px);
}
.sl-card:focus {
  outline: 2px solid var(--md-primary);
  outline-offset: 2px;
}
.sl-card-header {
  display: flex;
  align-items: center;
}
.sl-badge {
  padding: 3px 10px;
  border-radius: var(--radius-full);
  font-size: 11px;
  font-weight: 600;
  background: var(--md-primary-container);
  color: var(--md-on-primary-container);
  letter-spacing: 0.3px;
}
.sl-card-title {
  font-size: 16px;
  font-weight: 700;
  color: var(--md-on-surface);
  margin: 0;
  line-height: 1.4;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}
.sl-card-desc {
  font-size: 13px;
  color: var(--md-on-surface-variant);
  line-height: 1.6;
  margin: 0;
  flex: 1;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}
.sl-card-footer {
  display: flex;
  flex-direction: column;
  gap: 6px;
}
.sl-card-meta {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 12px;
  color: var(--md-on-surface-variant);
}
.sl-card-meta .material-icons { font-size: 14px; color: var(--md-primary); }
.sl-card-cta {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  margin-top: 4px;
  padding: 10px;
  border-radius: var(--radius-md);
  background: var(--md-primary);
  color: var(--md-on-primary);
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.3px;
  transition: background var(--transition-fast);
}
.sl-card:hover .sl-card-cta {
  background: var(--md-primary-dark);
}
.sl-card-cta .material-icons { font-size: 16px; }

/* Skeleton */
.sl-skeleton-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}
.sl-card-skeleton {
  height: 220px;
  border-radius: var(--radius-lg);
  background: linear-gradient(90deg, var(--md-surface-variant) 25%, var(--md-surface-2) 50%, var(--md-surface-variant) 75%);
  background-size: 200% 100%;
  animation: skeleton-shimmer 1.5s infinite;
}
@keyframes skeleton-shimmer {
  0% { background-position: 200% 0; }
  100% { background-position: -200% 0; }
}

/* Empty state */
.sl-empty {
  grid-column: 1 / -1;
  text-align: center;
  padding: 80px 20px;
  color: var(--md-on-surface-variant);
}
.sl-empty .material-icons {
  font-size: 56px;
  color: var(--md-outline-variant);
  display: block;
  margin-bottom: 16px;
}
.sl-empty p {
  font-size: 16px;
  margin: 0 0 20px;
}

/* Responsive */
@media (max-width: 900px) {
  .sl-grid-inner,
  .sl-skeleton-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}
@media (max-width: 600px) {
  .sl-hero {
    padding: 32px var(--sp-4) 28px;
  }
  .sl-hero-title { font-size: 22px; }
  .sl-grid-inner,
  .sl-skeleton-grid {
    grid-template-columns: 1fr;
  }
  .sl-filters {
    padding: 0 var(--sp-4);
  }
  .sl-content {
    padding: 0 var(--sp-4);
  }
}

/* ============================================================
   Template Cards
   ============================================================ */
.tpl-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 16px;
  margin-top: var(--sp-4);
}
.tpl-card {
  background: var(--md-surface);
  border: 1px solid var(--md-outline-variant);
  border-radius: var(--radius-lg);
  padding: 20px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}
.tpl-card__header {
  display: flex;
  align-items: center;
  gap: 8px;
}
.tpl-card__title {
  font-size: 15px;
  font-weight: 600;
  margin: 0;
  color: var(--md-on-surface);
}
.tpl-card__desc {
  font-size: 13px;
  color: var(--md-on-surface-variant);
  line-height: 1.5;
  margin: 0;
  flex: 1;
}
.tpl-card__actions {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-top: 4px;
}
.tpl-card__actions .btn {
  flex: 1;
  justify-content: center;
}

/* ============================================================
   AI Mode Layout
   ============================================================ */
.ai-layout {
  display: grid;
  grid-template-columns: 380px 1fr;
  gap: 24px;
  align-items: start;
}
.ai-input-panel {
  position: sticky;
  top: 80px;
}
.ai-result-panel {
  min-height: 200px;
}

.ai-section-card {
  border: 1px solid var(--md-outline-variant);
  border-radius: var(--radius-md);
  padding: 16px;
  margin-bottom: 12px;
  background: var(--md-surface);
}
.ai-section-header {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  margin-bottom: 12px;
}
.ai-section-num {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: var(--md-primary);
  color: var(--md-on-primary);
  font-size: 13px;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}
.ai-materials-list {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}
.ai-material-chip {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 4px 10px;
  border-radius: var(--radius-full);
  background: var(--md-secondary-container);
  color: var(--md-on-secondary-container);
  font-size: 12px;
}

@media (max-width: 900px) {
  .ai-layout {
    grid-template-columns: 1fr;
  }
  .ai-input-panel {
    position: static;
  }
}

/* ============================================================
   Dashboard Home
   ============================================================ */
.dash-stats {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
  margin-bottom: 28px;
}
.dash-stat-card {
  background: var(--md-surface);
  border: 1px solid var(--md-outline-variant);
  border-radius: var(--radius-lg);
  padding: 20px;
  display: flex;
  align-items: center;
  gap: 16px;
  box-shadow: var(--elevation-1);
}
.dash-stat-card--loading {
  height: 88px;
  background: linear-gradient(90deg, var(--md-surface-variant) 25%, var(--md-surface-2) 50%, var(--md-surface-variant) 75%);
  background-size: 200% 100%;
  animation: skeleton-shimmer 1.5s infinite;
}
.dash-stat-icon {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}
.dash-stat-icon .material-icons { font-size: 24px; }
.dash-stat-num {
  font-size: 32px;
  font-weight: 700;
  color: var(--md-on-surface);
  line-height: 1;
}
.dash-stat-label {
  font-size: 13px;
  color: var(--md-on-surface-variant);
  margin-top: 4px;
}
.dash-sections {
  display: grid;
  grid-template-columns: 1fr 320px;
  gap: 24px;
}
.dash-section {
  background: var(--md-surface);
  border: 1px solid var(--md-outline-variant);
  border-radius: var(--radius-lg);
  padding: 20px;
}
.dash-section-title {
  font-size: 14px;
  font-weight: 600;
  color: var(--md-on-surface-variant);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin: 0 0 16px;
  display: flex;
  align-items: center;
  gap: 6px;
}
.dash-section-title .material-icons { font-size: 16px; }
.dash-recent-row {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 10px 0;
  border-bottom: 1px solid var(--md-outline-variant);
}
.dash-recent-row:last-child { border-bottom: none; }
.dash-recent-title {
  flex: 1;
  font-size: 14px;
  font-weight: 500;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}
.dash-quick-actions {
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.dash-qa-btn {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 12px 16px;
  border-radius: var(--radius-md);
  border: 1px solid var(--md-outline-variant);
  background: var(--md-surface);
  color: var(--md-on-surface);
  cursor: pointer;
  font-size: 14px;
  font-family: var(--font-sans);
  font-weight: 500;
  transition: background var(--transition-fast);
  text-align: left;
}
.dash-qa-btn:hover { background: var(--md-surface-1); }
.dash-qa-btn .material-icons { color: var(--md-primary); font-size: 20px; }
@media (max-width: 900px) {
  .dash-stats { grid-template-columns: repeat(2, 1fr); }
  .dash-sections { grid-template-columns: 1fr; }
}
@media (max-width: 600px) {
  .dash-stats { grid-template-columns: repeat(2, 1fr); gap: 10px; }
}

/* ============================================================
   Seminar Detail — Split Layout (sd-*)
   ============================================================ */
.sd-layout {
  display: grid;
  grid-template-columns: 380px 1fr;
  gap: 0;
  height: calc(100vh - 64px - 120px); /* viewport minus appbar and seminar-header */
  min-height: 500px;
  position: relative;
}

.sd-sidebar {
  overflow-y: auto;
  padding: var(--sp-5);
  border-right: 1px solid var(--md-outline-variant);
  background: var(--md-surface);
  transition: width 0.25s ease, min-width 0.25s ease, padding 0.25s ease;
}

/* Sidebar toggle button (desktop only, hidden on mobile) */
.sd-sidebar__toggle {
  display: none; /* shown via media query on desktop */
}

.sd-sidebar__content {
  transition: opacity 0.2s ease;
}

/* Desktop: show toggle and support collapsing */
@media (min-width: 840px) {
  .sd-sidebar__toggle {
    display: flex;
    align-items: center;
    justify-content: center;
    position: absolute;
    top: 50%;
    left: 380px;
    transform: translateY(-50%);
    z-index: 20;
    width: 20px;
    height: 48px;
    border-radius: 0 6px 6px 0;
    border: 1px solid var(--md-outline-variant);
    border-left: none;
    background: var(--md-surface-1);
    color: var(--md-on-surface-variant);
    cursor: pointer;
    transition: background 0.15s, color 0.15s, width 0.15s, left 0.25s ease;
    padding: 0;
  }
  .sd-sidebar__toggle:hover {
    background: var(--md-primary-container);
    color: var(--md-primary);
    width: 24px;
  }
  .sd-sidebar__toggle .material-icons {
    font-size: 16px;
  }

  /* Collapsed state */
  .sd-sidebar--collapsed {
    width: 0 !important;
    min-width: 0 !important;
    padding: 0 !important;
    overflow: hidden;
    border-right: none;
  }
  .sd-sidebar--collapsed .sd-sidebar__content {
    opacity: 0;
    pointer-events: none;
  }

  /* Move toggle to left edge when collapsed */
  .sd-layout.sd-layout--collapsed .sd-sidebar__toggle {
    left: 0;
    background: var(--md-primary-container);
    color: var(--md-primary);
    width: 24px;
    height: 56px;
  }
  .sd-layout.sd-layout--collapsed .sd-sidebar__toggle:hover {
    background: var(--md-primary);
    color: var(--md-on-primary);
  }

  /* When collapsed, switch grid to give all space to viewer */
  .sd-layout.sd-layout--collapsed {
    grid-template-columns: 0px 1fr;
  }
}

.sd-viewer {
  display: flex;
  flex-direction: column;
  background: var(--md-background);
  overflow: hidden;
}

.sd-viewer__empty {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: var(--sp-8);
}

.sd-viewer__panel {
  flex: 1;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

.sd-viewer-toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--sp-3);
  padding: var(--sp-3) var(--sp-4);
  background: var(--md-surface);
  border-bottom: 1px solid var(--md-outline-variant);
  flex-shrink: 0;
  flex-wrap: wrap;
}

.sd-viewer-toolbar__info {
  display: flex;
  align-items: center;
  gap: var(--sp-3);
  min-width: 0;
  flex: 1;
}

.sd-viewer-toolbar__actions {
  display: flex;
  align-items: center;
  gap: var(--sp-2);
  flex-shrink: 0;
}

.sd-viewer-frame {
  flex: 1;
  overflow: hidden;
}

/* Mobile: stack vertically */
@media (max-width: 839px) {
  .sd-layout {
    grid-template-columns: 1fr;
    grid-template-rows: auto 1fr;
    height: auto;
    min-height: unset;
  }

  .sd-sidebar {
    border-right: none;
    border-bottom: 1px solid var(--md-outline-variant);
    max-height: 50vh;
    overflow-y: auto;
    -webkit-overflow-scrolling: touch;
  }

  .material-card {
    min-height: 56px; /* Minimum tap target per WCAG */
    padding: var(--sp-4) var(--sp-3);
  }

  .sd-viewer {
    height: 70vh;
    min-height: 400px;
  }
}

/* ============================================================
   Feature 8: Drag & Drop 並び替え
   ============================================================ */
.drag-handle {
  opacity: 0.4;
  transition: opacity 0.15s;
}
.drag-handle:hover {
  opacity: 1;
  color: var(--md-primary) !important;
}
[draggable="true"]:active .drag-handle,
[draggable="true"].dragging .drag-handle {
  cursor: grabbing;
}
[draggable="true"].drag-over {
  outline: 2px dashed var(--md-primary);
  outline-offset: 2px;
}
.dnd-placeholder {
  height: 3px;
  background: var(--md-primary);
  border-radius: 2px;
  margin: 2px 0;
}


/* ============================================================
   Region / Area Selector (Participant Landing)
   ============================================================ */
.region-selector-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: var(--sp-4);
  padding: var(--sp-6) 0;
}

.region-card {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: var(--sp-2);
  padding: var(--sp-5);
  background: var(--md-surface);
  border: 1px solid var(--md-outline-variant);
  border-radius: var(--radius-lg);
  cursor: pointer;
  text-align: left;
  transition: background 0.18s, box-shadow 0.18s, border-color 0.18s;
  box-shadow: var(--elevation-1);
}

.region-card:hover, .region-card:focus-visible {
  background: var(--md-surface-1);
  border-color: var(--md-primary);
  box-shadow: var(--elevation-2);
  outline: none;
}

.region-card__icon {
  color: var(--md-primary);
  font-size: 32px;
}

.region-card__name {
  font-size: 18px;
  font-weight: 600;
  color: var(--md-on-surface);
}

.region-card__desc {
  font-size: 13px;
  color: var(--md-on-surface-variant);
  line-height: 1.5;
}

/* ============================================================
   Text viewer frame (for text/prompt materials)
   ============================================================ */
#sd-viewer-frame-text {
  display: flex;
  flex-direction: column;
  width: 100%;
  height: 100%;
}

#sd-viewer-frame-image {
  display: flex;
  width: 100%;
  height: 100%;
  background: var(--md-surface-1);
  align-items: center;
  justify-content: center;
  overflow: hidden;
}

.sd-viewer-frame {
  width: 100%;
  height: 100%;
  overflow: hidden;
}

/* iframe frame needs flex display when shown */
#sd-viewer-frame-iframe {
  display: flex;
}

/* ============================================================
   Mobile UX improvements (スマホ対応強化)
   ============================================================ */

/* Google Meet button */
.meet-join-btn {
  background: #1a73e8 !important;
  border-color: #1a73e8 !important;
  color: #fff !important;
  padding: 8px 16px;
  font-size: 13px;
}
.meet-join-btn:hover {
  background: #1558b0 !important;
}

/* Top app bar: hide text labels on very small screens */
@media (max-width: 480px) {
  .btn-label-desktop {
    display: none;
  }
  .top-app-bar__title {
    font-size: 14px;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    max-width: 160px;
  }
}

/* Tabs: horizontal scroll on mobile, don't shrink */
.tabs {
  -webkit-overflow-scrolling: touch;
  scrollbar-width: none;
}
.tabs::-webkit-scrollbar { display: none; }

@media (max-width: 600px) {
  .tab {
    padding: var(--sp-2) var(--sp-3);
    font-size: 12px;
    gap: var(--sp-1);
    flex-shrink: 0;
    white-space: nowrap;
  }
  .tab .material-icons {
    font-size: 18px;
  }

  /* Tab panels: less padding on mobile */
  .tab-panel {
    padding: var(--sp-4) 0;
  }

  /* Admin main: tighter padding */
  .admin-main {
    padding: var(--sp-3) !important;
  }

  /* Full-width fields on mobile */
  #tab-panel-basic > div,
  #tab-panel-access > div {
    max-width: 100% !important;
  }

  /* Grid to single column on mobile */
  [style*="grid-template-columns:1fr 1fr"] {
    display: flex !important;
    flex-direction: column !important;
    gap: 0 !important;
  }

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

  /* Page header */
  .page-header {
    gap: var(--sp-3);
  }
  .page-header__title {
    font-size: 20px;
  }

  /* Card padding */
  .card {
    padding: var(--sp-4);
  }

  /* Login page full screen */
  .login-page {
    padding: var(--sp-4);
    align-items: flex-start;
  }
  .login-card {
    width: 100%;
    max-width: 100%;
    border-radius: var(--radius-md);
    box-shadow: none;
    padding: var(--sp-5);
  }

  /* Seminar detail layout */
  .sd-layout {
    grid-template-columns: 1fr !important;
  }

  /* Region selector: single column */
  .region-selector-grid {
    grid-template-columns: 1fr;
  }

  /* Chip group: wrap */
  .chip-group {
    flex-wrap: wrap;
  }

  /* Button text wrapping */
  .btn {
    white-space: normal;
    text-align: center;
  }

  /* Section editor: stack action buttons */
  [data-section-id] > div:first-child {
    flex-wrap: wrap;
  }

  /* Access tab: URL inputs flex-column on mobile */
  #tab-panel-access .field-group [style*="display:flex"] {
    flex-direction: column;
  }

  /* Seminar header */
  .seminar-header {
    padding: var(--sp-4);
  }
  .seminar-header__title {
    font-size: 20px !important;
  }
  .seminar-header__meta {
    flex-direction: column;
    align-items: flex-start;
    gap: var(--sp-1);
  }
}

/* Admin top app bar actions: compact on small screens */
@media (max-width: 480px) {
  .top-app-bar__actions {
    gap: var(--sp-1);
  }
  .top-app-bar__actions > *:not(.btn-icon):not(.meet-join-btn):not(#save-btn):not(#certificate-btn) {
    display: none;
  }
  /* 保存ボタンをモバイルでコンパクトに */
  #save-btn {
    padding: 6px 12px !important;
    font-size: 12px !important;
  }
  .meet-join-btn .btn-label-desktop {
    display: none;
  }
  .meet-join-btn {
    padding: 8px 12px !important;
  }
}

/* Seminar list chips: horizontal scroll */
.seminar-chip-group {
  display: flex;
  gap: var(--sp-2);
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: none;
  padding-bottom: var(--sp-1);
}
.seminar-chip-group::-webkit-scrollbar { display: none; }

/* ============================================================
   Google Meet Banner (セミナー詳細 最上部の目立つバナー)
   ============================================================ */
.meet-banner {
  background: linear-gradient(135deg, #1a73e8 0%, #0d5dc7 100%);
  color: #fff;
  padding: 0;
  flex-shrink: 0;
}
.meet-banner__inner {
  display: flex;
  align-items: center;
  gap: var(--sp-3);
  padding: var(--sp-3) var(--sp-5);
  max-width: 100%;
}
.meet-banner__icon {
  font-size: 28px;
  flex-shrink: 0;
  opacity: 0.9;
}
.meet-banner__text {
  display: flex;
  flex-direction: column;
  gap: 2px;
  flex: 1;
  min-width: 0;
}
.meet-banner__label {
  font-size: 15px;
  font-weight: 600;
  line-height: 1.2;
}
.meet-banner__sublabel {
  font-size: 12px;
  opacity: 0.8;
  line-height: 1.2;
}
.meet-banner__btn {
  display: inline-flex;
  align-items: center;
  gap: var(--sp-2);
  padding: 8px 18px;
  background: #fff;
  color: #1a73e8;
  border-radius: 20px;
  font-size: 14px;
  font-weight: 700;
  text-decoration: none;
  white-space: nowrap;
  flex-shrink: 0;
  transition: background 0.15s, box-shadow 0.15s;
  box-shadow: 0 2px 6px rgba(0,0,0,0.15);
}
.meet-banner__btn:hover {
  background: #e8f0fe;
  box-shadow: 0 4px 10px rgba(0,0,0,0.2);
}
.meet-banner__btn .material-icons {
  font-size: 18px;
}
@media (max-width: 600px) {
  .meet-banner__inner {
    padding: var(--sp-3) var(--sp-4);
    gap: var(--sp-2);
  }
  .meet-banner__sublabel { display: none; }
  .meet-banner__btn {
    padding: 7px 12px;
    font-size: 13px;
  }
}

/* ============================================================
   Seminar Info Toggle (セミナー情報 折りたたみパネル)
   ============================================================ */
.seminar-info-toggle {
  border-top: 1px solid rgba(255,255,255,0.15);
  margin-top: var(--sp-3);
}
.seminar-info-toggle__btn {
  display: flex;
  align-items: center;
  gap: var(--sp-2);
  width: 100%;
  background: none;
  border: none;
  color: inherit;
  cursor: pointer;
  padding: var(--sp-2) 0 var(--sp-2);
  font-size: 14px;
  font-weight: 500;
  opacity: 0.9;
  transition: opacity 0.15s;
}
.seminar-info-toggle__btn:hover { opacity: 1; }
.seminar-info-toggle__btn .material-icons { font-size: 20px; }
.seminar-info-toggle__icon {
  margin-left: auto;
  transition: transform 0.2s;
}
.seminar-info-toggle__btn[aria-expanded="true"] .seminar-info-toggle__icon {
  transform: rotate(180deg);
}
.seminar-info-panel {
  background: rgba(0,0,0,0.12);
  border-radius: var(--radius-sm);
  padding: var(--sp-4);
  margin-bottom: var(--sp-3);
  font-size: 14px;
  line-height: 1.6;
}
.seminar-info-panel p {
  margin: 0 0 var(--sp-3);
  white-space: pre-wrap;
}
.seminar-info-panel p:last-child { margin-bottom: 0; }
.seminar-info-panel a {
  color: #a8d4ff;
  text-decoration: underline;
}
.seminar-info-panel__label {
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.8px;
  opacity: 0.7;
  margin-bottom: var(--sp-1);
  display: block;
}
@media (max-width: 600px) {
  .seminar-info-panel {
    padding: var(--sp-3);
    font-size: 13px;
  }
}