/* ==========================================================================
   Compendium Reader — Material Design 3 styling (light theme defaults)
   ========================================================================== */

:root {
  --md-primary: #1565c0;
  --md-primary-hover: #0d47a1;
  --md-on-primary: #ffffff;
  --md-primary-container: #d3e3fd;
  --md-on-primary-container: #041e49;

  --md-background: #f5f5f5;
  --md-surface: #ffffff;
  --md-surface-variant: #e7e9ec;
  --md-on-surface: #1c1b1f;
  --md-on-surface-variant: #49454f;
  --md-outline: #79747e;
  --md-outline-variant: #c9c5d0;

  --md-elevation-1: 0 1px 2px rgba(0, 0, 0, 0.08), 0 1px 3px rgba(0, 0, 0, 0.10);
  --md-elevation-2: 0 2px 6px rgba(0, 0, 0, 0.10), 0 4px 12px rgba(0, 0, 0, 0.08);
  --md-elevation-3: 0 4px 12px rgba(0, 0, 0, 0.12), 0 8px 24px rgba(0, 0, 0, 0.10);

  --radius-lg: 28px;
  --radius-md: 20px;
  --radius-sm: 12px;

  --transition-fast: 180ms cubic-bezier(0.2, 0, 0, 1);
  --transition-med: 280ms cubic-bezier(0.2, 0, 0, 1);

  color-scheme: light;
}

* {
  box-sizing: border-box;
}

html,
body {
  height: 100%;
}

body {
  margin: 0;
  font-family: "Roboto", "Segoe UI", system-ui, -apple-system, sans-serif;
  background: var(--md-background);
  color: var(--md-on-surface);
  overflow-x: hidden;
  transition: background-color var(--transition-med), color var(--transition-med);
}

a {
  text-decoration: none;
  color: inherit;
}

button {
  font-family: inherit;
}

/* --------------------------------------------------------------------------
   Loading screen
   -------------------------------------------------------------------------- */

#loadingScreen {
  position: fixed;
  inset: 0;
  z-index: 2000;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 20px;
  background: var(--md-background);
  transition: opacity var(--transition-med), visibility var(--transition-med);
}

#loadingScreen.is-hidden {
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
}

.md-loader {
  width: 56px;
  height: 56px;
  border-radius: 50%;
  border: 4px solid var(--md-primary-container);
  border-top-color: var(--md-primary);
  animation: md-spin 900ms linear infinite;
}

.md-loader.loader-sm {
  width: 32px;
  height: 32px;
  border-width: 3px;
}

.loading-title {
  font-size: 1.4rem;
  font-weight: 500;
  color: var(--md-on-surface);
  letter-spacing: 0.1px;
}

.loading-subtitle {
  font-size: 0.95rem;
  color: var(--md-on-surface-variant);
}

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

/* Page (content) fade in/out, separate from loader */
#appRoot {
  opacity: 0;
  transition: opacity var(--transition-med);
}

#appRoot.is-visible {
  opacity: 1;
}

.page-content {
  transition: opacity 200ms ease;
}

.page-content.is-leaving {
  opacity: 0;
}

/* --------------------------------------------------------------------------
   Reading progress bar
   -------------------------------------------------------------------------- */

#readingProgress {
  position: fixed;
  top: 0;
  left: 0;
  height: 3px;
  width: 0%;
  background: var(--md-primary);
  z-index: 1100;
  transition: width var(--transition-med);
}

/* --------------------------------------------------------------------------
   Top App Bar
   -------------------------------------------------------------------------- */

.md-appbar {
  position: sticky;
  top: 0;
  z-index: 1030;
  background: var(--md-surface);
  color: var(--md-on-surface);
  box-shadow: var(--md-elevation-1);
  padding: 0.5rem 1rem;
  border-radius: 0 0 var(--radius-sm) var(--radius-sm);
}

.md-appbar .navbar-brand {
  font-weight: 600;
  color: var(--md-on-surface);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.md-appbar .navbar-brand .brand-icon {
  color: var(--md-primary);
}

.appbar-page-title {
  font-size: 0.95rem;
  color: var(--md-on-surface-variant);
  font-weight: 500;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.icon-btn {
  width: 40px;
  height: 40px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border: none;
  background: transparent;
  color: var(--md-on-surface-variant);
  border-radius: 50%;
  position: relative;
  overflow: hidden;
  transition: background-color var(--transition-fast), color var(--transition-fast);
}

.icon-btn:hover,
.icon-btn:focus-visible {
  background: var(--md-surface-variant);
  color: var(--md-on-surface);
}

.icon-btn:disabled {
  opacity: 0.35;
  pointer-events: none;
}

.icon-btn.active {
  background: var(--md-primary-container);
  color: var(--md-on-primary-container);
}

.zoom-group {
  display: flex;
  align-items: center;
  gap: 2px;
  background: var(--md-background);
  border-radius: 999px;
  padding: 2px;
}

.zoom-level {
  min-width: 3.2rem;
  text-align: center;
  font-size: 0.85rem;
  color: var(--md-on-surface-variant);
  user-select: none;
}

/* --------------------------------------------------------------------------
   Navigation Drawer
   -------------------------------------------------------------------------- */

.offcanvas.md-drawer {
  width: 300px;
  background: var(--md-surface);
  border: none;
  border-radius: 0 var(--radius-lg) var(--radius-lg) 0;
}

.md-drawer .offcanvas-header {
  padding: 1.25rem 1rem 0.5rem;
}

.md-drawer .drawer-title {
  font-weight: 600;
  font-size: 1.1rem;
}

.drawer-nav {
  list-style: none;
  margin: 0;
  padding: 0.25rem 0.75rem 1rem;
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.drawer-nav .drawer-link {
  display: flex;
  align-items: center;
  gap: 0.85rem;
  padding: 0.65rem 1rem;
  border-radius: 999px;
  color: var(--md-on-surface-variant);
  font-size: 0.95rem;
  transition: background-color var(--transition-fast), color var(--transition-fast);
}

.drawer-nav .drawer-link:hover,
.drawer-nav .drawer-link:focus-visible {
  background: var(--md-surface-variant);
  color: var(--md-on-surface);
}

.drawer-nav .drawer-link.active {
  background: var(--md-primary-container);
  color: var(--md-on-primary-container);
  font-weight: 600;
}

.drawer-nav .drawer-link i {
  font-size: 1.15rem;
  width: 1.4rem;
  text-align: center;
}

.drawer-divider {
  height: 1px;
  background: var(--md-outline-variant);
  margin: 0.5rem 1rem;
  border: none;
}

/* --------------------------------------------------------------------------
   Content Area
   -------------------------------------------------------------------------- */

.content-wrap {
  padding: 1.5rem 1rem 7rem;
  display: flex;
  justify-content: center;
}

.page-card {
  background: var(--md-surface);
  border-radius: var(--radius-lg);
  box-shadow: var(--md-elevation-2);
  padding: 1.5rem;
  max-width: 980px;
  width: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.image-viewport {
  width: 100%;
  overflow: auto;
  display: flex;
  justify-content: center;
  align-items: flex-start;
  border-radius: var(--radius-md);
  background: var(--md-surface);
  touch-action: pan-y;
  position: relative;
}

.image-viewport .img-spinner {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
}

.page-image {
  max-width: 100%;
  height: auto;
  display: block;
  border-radius: var(--radius-sm);
  transform-origin: center top;
  transition: transform var(--transition-fast), opacity var(--transition-med);
  opacity: 0;
  user-select: none;
  -webkit-user-drag: none;
}

.page-image.is-loaded {
  opacity: 1;
}

.image-viewport.is-zoomed {
  justify-content: flex-start;
  align-items: flex-start;
  cursor: grab;
}

/* --------------------------------------------------------------------------
   Bottom Floating Navigation Bar
   -------------------------------------------------------------------------- */

.bottom-nav {
  position: fixed;
  left: 50%;
  bottom: 1.25rem;
  transform: translateX(-50%);
  z-index: 1040;
  display: flex;
  align-items: center;
  gap: 0.35rem;
  background: var(--md-surface);
  box-shadow: var(--md-elevation-3);
  border-radius: 999px;
  padding: 0.4rem 0.6rem;
  max-width: calc(100vw - 1.5rem);
}

.bottom-nav .page-indicator {
  font-size: 0.85rem;
  color: var(--md-on-surface-variant);
  padding: 0 0.5rem;
  white-space: nowrap;
}

.goto-form {
  display: flex;
  align-items: center;
  gap: 0.25rem;
}

.goto-input {
  width: 4.2rem;
  border: 1px solid var(--md-outline-variant);
  border-radius: 999px;
  text-align: center;
  padding: 0.35rem 0.25rem;
  background: var(--md-background);
  color: var(--md-on-surface);
  font-size: 0.85rem;
}

.goto-input:focus {
  outline: 2px solid var(--md-primary);
  outline-offset: 1px;
}

.goto-submit {
  background: var(--md-primary);
  color: var(--md-on-primary);
  border: none;
  border-radius: 999px;
  padding: 0.4rem 0.9rem;
  font-size: 0.85rem;
  font-weight: 500;
  transition: background-color var(--transition-fast);
}

.goto-submit:hover {
  background: var(--md-primary-hover);
}

/* Ripple effect */
.ripple-surface {
  position: relative;
  overflow: hidden;
}

.ripple {
  position: absolute;
  border-radius: 50%;
  background: currentColor;
  opacity: 0.28;
  transform: scale(0);
  animation: ripple-anim 500ms ease-out;
  pointer-events: none;
}

@keyframes ripple-anim {
  to {
    transform: scale(2.6);
    opacity: 0;
  }
}

/* --------------------------------------------------------------------------
   Scroll-to-top FAB
   -------------------------------------------------------------------------- */

.scroll-fab {
  position: fixed;
  right: 1.25rem;
  bottom: 6rem;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: var(--md-primary);
  color: var(--md-on-primary);
  border: none;
  box-shadow: var(--md-elevation-2);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  z-index: 1035;
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
  transition: opacity var(--transition-fast), transform var(--transition-fast), visibility var(--transition-fast);
}

.scroll-fab.is-visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

/* --------------------------------------------------------------------------
   Toasts
   -------------------------------------------------------------------------- */

.toast-container {
  z-index: 1080;
}

.md-toast {
  border-radius: var(--radius-sm);
  border: none;
  box-shadow: var(--md-elevation-2);
  background: var(--md-surface);
  color: var(--md-on-surface);
}

/* --------------------------------------------------------------------------
   Focus & accessibility
   -------------------------------------------------------------------------- */

a:focus-visible,
button:focus-visible,
input:focus-visible {
  outline: 2px solid var(--md-primary);
  outline-offset: 2px;
}

@media (prefers-contrast: more) {
  .page-card,
  .md-appbar,
  .bottom-nav,
  .offcanvas.md-drawer {
    border: 1px solid var(--md-on-surface);
  }
}

.visually-hidden-focusable:not(:focus):not(:focus-within) {
  position: absolute !important;
  width: 1px; height: 1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
}

/* --------------------------------------------------------------------------
   Table of Contents pages — recreated as real, selectable text with links
   (instead of a screenshot) but kept on the source document's own light
   blue background, sampled from the original scanned pages (#e1f4fd).
   -------------------------------------------------------------------------- */

.toc-viewport {
  width: 100%;
  border-radius: var(--radius-md);
  background: #e1f4fd;
  padding: 1.5rem clamp(1rem, 4vw, 2.5rem) 2rem;
  color: #231f20;
}

.toc-title {
  text-align: center;
  font-size: 1.5rem;
  font-weight: 700;
  margin: 0 0 1.25rem;
}

.toc-grid {
  display: grid;
  grid-template-columns: 3rem 1fr 4.5rem;
  column-gap: 0.75rem;
  row-gap: 0.6rem;
  align-items: baseline;
}

.toc-col-head {
  font-weight: 700;
  padding-bottom: 0.5rem;
  border-bottom: 2px solid rgba(35, 31, 32, 0.3);
}

.toc-chapter {
  grid-column: 1 / -1;
  color: #9e0a0e;
  font-weight: 700;
  font-size: 1.05rem;
  text-align: center;
  margin: 0.9rem 0 0.15rem;
}

.toc-subsection {
  grid-column: 1 / -1;
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  color: #2e3092;
  font-weight: 700;
  margin: 0.5rem 0 0.1rem;
}

.toc-no {
  text-align: left;
}

.toc-name a {
  /* Hardcoded, not var(--md-primary): the sheet behind it is a fixed
     light background in both themes, so the link color must stay fixed
     too, or it loses contrast under the dark-theme palette. */
  color: #1565c0;
  text-decoration: none;
  border-radius: 4px;
}

.toc-name a:hover,
.toc-name a:focus-visible {
  text-decoration: underline;
}

.toc-pageno {
  text-align: right;
}

@media (max-width: 575.98px) {
  .toc-grid { grid-template-columns: 2.2rem 1fr 3.2rem; column-gap: 0.5rem; }
  .toc-viewport { padding: 1.25rem 1rem 1.5rem; }
  .toc-subsection { flex-direction: column; gap: 0.15rem; }
}

/* --------------------------------------------------------------------------
   Responsive
   -------------------------------------------------------------------------- */

@media (max-width: 575.98px) {
  .appbar-page-title { max-width: 40vw; }
  .page-card { padding: 1rem; border-radius: var(--radius-md); }
  .bottom-nav { gap: 0.15rem; padding: 0.3rem 0.4rem; }
  .goto-input { width: 3.4rem; }
  .content-wrap { padding: 1rem 0.5rem 7rem; }
}

@media (min-width: 1400px) {
  .page-card { max-width: 1140px; }
}

/* Fullscreen mode tweaks */
:fullscreen .content-wrap,
:-webkit-full-screen .content-wrap {
  padding-top: 1rem;
}

/* Reduced motion */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.001ms !important;
    transition-duration: 0.001ms !important;
  }
}