/* ───────────────────────────────────────────────────────────────
   Flipbook Viewer — responsive, full-viewport, dark theme
   Apple-inspired: clarity, depth, subtle glass, natural motion
   ─────────────────────────────────────────────────────────────── */

* {
  box-sizing: border-box;
  -webkit-tap-highlight-color: transparent;
}

html,
body {
  margin: 0;
  padding: 0;
  height: 100%;
  background: #0a0a0a;
  color: #f5f5f7;
  font-family:
    -apple-system, BlinkMacSystemFont, "SF Pro Text", "Inter", system-ui,
    "Segoe UI", Roboto, sans-serif;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overscroll-behavior: none;
  overflow: hidden;
}

body {
  display: flex;
  align-items: center;
  justify-content: center;
  position: fixed;
  inset: 0;
  /* Allow native pinch-to-zoom for reading body text on phones.
     StPageFlip still handles single-finger swipe gestures on the book element
     because pinch (2 fingers) and swipe (1 finger) don't conflict. */
  touch-action: pinch-zoom pan-y;
}

/* ─── Ambient Backdrop (blurred current page as environment) ─── */
#backdrop-image {
  position: fixed;
  inset: -10%;
  background-color: #0a0a0a;
  background-image: var(--bg-image, none);
  background-size: cover;
  background-position: center;
  background-repeat: no-repeat;
  filter: blur(100px) brightness(0.38) saturate(1.4);
  transform: scale(1.3) translateZ(0);
  z-index: 0;
  transition: filter 0.6s ease-out;
  will-change: background-image;
  pointer-events: none;
}

#backdrop-overlay {
  position: fixed;
  inset: 0;
  background: radial-gradient(
    ellipse at center,
    rgba(10, 10, 10, 0.4) 0%,
    rgba(5, 5, 5, 0.78) 70%,
    rgba(0, 0, 0, 0.92) 100%
  );
  z-index: 1;
  pointer-events: none;
}

#app {
  position: relative;
  z-index: 2;
  width: 100%;
  height: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}

/* ─── Loader ─────────────────────────────────────────────────── */
.loader {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 22px;
  background: radial-gradient(
    ellipse at center,
    #1a1a1a 0%,
    #0a0a0a 70%
  );
  z-index: 100;
  transition: opacity 0.5s ease;
}

.loader.hidden {
  opacity: 0;
  pointer-events: none;
}

.loader__pulse {
  width: 56px;
  height: 56px;
  border: 2px solid rgba(255, 255, 255, 0.08);
  border-top-color: rgba(255, 255, 255, 0.85);
  border-radius: 50%;
  animation: spin 0.9s cubic-bezier(0.4, 0, 0.2, 1) infinite;
}

.loader__label {
  font-size: 13px;
  font-weight: 500;
  letter-spacing: 0.02em;
  color: rgba(255, 255, 255, 0.55);
}

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

/* ─── Book container ─────────────────────────────────────────── */
#book-container {
  width: 100%;
  flex: 1 1 auto;
  display: flex;
  align-items: center;
  justify-content: center;
  /* Reduced horizontal padding so the book takes more screen width
     on mobile (was 24px → 8px = ~14% larger book on phones) */
  padding: 12px 8px;
  padding-bottom: 90px;
  min-height: 0;
}

#book {
  max-width: 100%;
  max-height: 100%;
  filter: drop-shadow(0 25px 60px rgba(0, 0, 0, 0.6));
}

/* StPageFlip page backgrounds — covers both Canvas mode (.stf__parent .page)
   and HTML mode (direct .page children). HTML mode gives native DPR scaling
   so images render crisply on retina/HiDPI displays. */
.stf__parent .page,
#book .page {
  background: #151515;
  background-size: cover;
  background-position: center;
  overflow: hidden;
}

.stf__parent img,
#book .page img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
  user-select: none;
  -webkit-user-drag: none;
  image-rendering: -webkit-optimize-contrast;
}

/* ─── Controls (floating glass bar) ──────────────────────────── */
.controls {
  position: fixed;
  bottom: 24px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 10px 18px;
  background: rgba(22, 22, 22, 0.72);
  backdrop-filter: blur(24px) saturate(180%);
  -webkit-backdrop-filter: blur(24px) saturate(180%);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: 100px;
  z-index: 50;
  box-shadow:
    0 12px 40px rgba(0, 0, 0, 0.5),
    inset 0 1px 0 rgba(255, 255, 255, 0.06);
}

.ctrl {
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: transparent;
  border: none;
  color: #f5f5f7;
  cursor: pointer;
  border-radius: 50%;
  transition:
    background 0.18s ease,
    transform 0.1s ease;
}

.ctrl:hover {
  background: rgba(255, 255, 255, 0.08);
}

.ctrl:active {
  background: rgba(255, 255, 255, 0.14);
  transform: scale(0.94);
}

.ctrl:disabled {
  opacity: 0.3;
  cursor: not-allowed;
}

.ctrl--toc {
  margin-right: 2px;
}

/* ─── Zoom mode (CSS zoom property — WebKit/Blink supported) ── */
#book-container.zoomed {
  overflow: auto;
  -webkit-overflow-scrolling: touch;
  align-items: flex-start;
  padding-top: 30px;
}

#book-container.zoomed #book {
  zoom: 1.75;
  /* Drop-shadow looks weird at zoom; soften it */
  filter: drop-shadow(0 15px 30px rgba(0, 0, 0, 0.5));
}

/* While zoomed, disable StPageFlip's hit detection so the user can
   pan around without accidentally triggering page flips. They use
   the prev/next buttons in the controls bar to flip while zoomed. */
#book-container.zoomed .stf__parent,
#book-container.zoomed .stf__parent * {
  pointer-events: none !important;
}

.page-indicator {
  font-size: 13px;
  font-variant-numeric: tabular-nums;
  font-weight: 500;
  color: rgba(255, 255, 255, 0.88);
  min-width: 64px;
  text-align: center;
  letter-spacing: 0.03em;
}

/* ─── Table of Contents Drawer ───────────────────────────────── */
.toc-scrim {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.45);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  z-index: 2999; /* above reader-mode (2000) so TOC works in reader */
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.3s ease;
}

.toc-scrim.open {
  opacity: 1;
  pointer-events: auto;
}

.toc-drawer {
  position: fixed;
  top: 0;
  right: 0;
  bottom: 0;
  width: min(460px, 92vw);
  background: rgba(15, 15, 15, 0.88);
  backdrop-filter: blur(36px) saturate(180%);
  -webkit-backdrop-filter: blur(36px) saturate(180%);
  border-left: 1px solid rgba(255, 255, 255, 0.08);
  z-index: 3000; /* above reader-mode so user can open TOC from reader */
  transform: translateX(102%);
  transition: transform 0.42s cubic-bezier(0.32, 0.72, 0, 1);
  display: flex;
  flex-direction: column;
  box-shadow: -30px 0 80px rgba(0, 0, 0, 0.5);
}

.toc-drawer.open {
  transform: translateX(0);
}

.toc-drawer__header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 22px 18px 18px 26px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.06);
  flex-shrink: 0;
}

.toc-drawer__title {
  font-size: 15px;
  font-weight: 600;
  letter-spacing: 0.01em;
  margin: 0;
  color: rgba(255, 255, 255, 0.95);
}

.ctrl--toc-close {
  width: 36px;
  height: 36px;
}

.toc-drawer__list {
  flex: 1 1 auto;
  overflow-y: auto;
  padding: 10px 0 40px;
  scrollbar-width: thin;
  scrollbar-color: rgba(255, 255, 255, 0.2) transparent;
  min-height: 0;
}

.toc-drawer__list::-webkit-scrollbar {
  width: 6px;
}

.toc-drawer__list::-webkit-scrollbar-thumb {
  background: rgba(255, 255, 255, 0.18);
  border-radius: 3px;
}

.toc-drawer__list::-webkit-scrollbar-track {
  background: transparent;
}

.toc-entry {
  display: flex;
  align-items: baseline;
  width: 100%;
  text-align: left;
  padding: 10px 26px 10px 26px;
  background: transparent;
  border: none;
  color: rgba(255, 255, 255, 0.75);
  font-family: inherit;
  font-size: 13px;
  line-height: 1.45;
  cursor: pointer;
  transition:
    background 0.15s ease,
    color 0.15s ease;
  position: relative;
  gap: 12px;
}

.toc-entry:hover {
  background: rgba(255, 255, 255, 0.05);
  color: #fff;
}

.toc-entry:active {
  background: rgba(255, 255, 255, 0.1);
}

.toc-entry__page {
  flex: 0 0 36px;
  color: rgba(255, 255, 255, 0.4);
  font-size: 11px;
  font-variant-numeric: tabular-nums;
  text-align: right;
  padding-top: 1px;
}

.toc-entry__title {
  flex: 1 1 auto;
  min-width: 0;
  overflow: hidden;
  text-overflow: ellipsis;
}

.toc-entry--level-1 {
  font-size: 14px;
  font-weight: 600;
  color: rgba(255, 255, 255, 0.95);
  padding-top: 16px;
  padding-bottom: 12px;
  margin-top: 6px;
  border-top: 1px solid rgba(255, 255, 255, 0.06);
}

.toc-entry--level-1:first-child {
  border-top: none;
  margin-top: 0;
  padding-top: 10px;
}

.toc-entry--level-2 {
  padding-left: 44px;
  font-weight: 400;
}

.toc-entry--level-2 .toc-entry__page {
  flex-basis: 28px;
}

.toc-entry--level-3 {
  padding-left: 62px;
  font-size: 12px;
  color: rgba(255, 255, 255, 0.55);
}

.toc-entry--level-3 .toc-entry__page {
  flex-basis: 28px;
}

.toc-entry--active {
  color: #fff;
  background: rgba(255, 255, 255, 0.08);
}

.toc-entry--active::before {
  content: "";
  position: absolute;
  left: 0;
  top: 15%;
  bottom: 15%;
  width: 3px;
  background: #fff;
  border-radius: 0 2px 2px 0;
}

/* ─── Immersive (fullscreen) mode ────────────────────────────── */
body.immersive #backdrop-overlay {
  background: radial-gradient(
    ellipse at center,
    rgba(0, 0, 0, 0.3) 0%,
    rgba(0, 0, 0, 0.85) 75%,
    rgba(0, 0, 0, 0.95) 100%
  );
}

body.immersive #book-container {
  padding: 8px;
  padding-bottom: 8px;
}

body.immersive .controls {
  opacity: 0;
  pointer-events: none;
  transform: translateX(-50%) translateY(140%);
  transition:
    opacity 0.35s ease,
    transform 0.35s cubic-bezier(0.32, 0.72, 0, 1);
}

body.immersive.ui-visible .controls {
  opacity: 1;
  pointer-events: auto;
  transform: translateX(-50%) translateY(0);
}

/* When the TOC drawer is open in immersive mode, keep it visible */
body.immersive .toc-drawer.open ~ .controls,
body.immersive:has(.toc-drawer.open) .controls {
  opacity: 1;
  pointer-events: auto;
  transform: translateX(-50%) translateY(0);
}

/* Native fullscreen backdrop */
#app:fullscreen,
#app:-webkit-full-screen {
  background: #0a0a0a;
}

:fullscreen #book-container,
:-webkit-full-screen #book-container {
  padding: 8px;
}

/* ─── Read Mode (reflowable dark reader) ────────────────────── */
.reader-mode {
  position: fixed;
  inset: 0;
  background: #0a0a0a;
  color: #d4d4d4;
  z-index: 2000;
  display: flex;
  flex-direction: column;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.35s ease;
  /* Font-family: warm serif for reading comfort. Crimson Pro would be
     ideal here but we use system serif fallbacks to avoid a web font
     request. On iOS, -apple-system-serif gives "New York" on modern iOS. */
  font-family:
    "New York", "Iowan Old Style", "Palatino Linotype", Palatino,
    Georgia, "Times New Roman", serif;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

.reader-mode.open {
  opacity: 1;
  pointer-events: auto;
}

.reader-header {
  flex: 0 0 auto;
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 16px 20px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.06);
  background: rgba(10, 10, 10, 0.92);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  position: sticky;
  top: 0;
  z-index: 10;
}

.reader-header__title {
  flex: 1 1 auto;
  font-family:
    -apple-system, BlinkMacSystemFont, "SF Pro Text", "Inter", system-ui,
    sans-serif;
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 0.01em;
  margin: 0;
  color: rgba(255, 255, 255, 0.92);
  text-align: center;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.reader-ctrl {
  flex: 0 0 auto;
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: transparent;
  border: none;
  color: #f5f5f7;
  cursor: pointer;
  border-radius: 50%;
  transition:
    background 0.18s ease,
    transform 0.1s ease;
}

.reader-ctrl:hover {
  background: rgba(255, 255, 255, 0.08);
}

.reader-ctrl:active {
  background: rgba(255, 255, 255, 0.14);
  transform: scale(0.94);
}

.reader-font-controls {
  flex: 0 0 auto;
  display: flex;
  gap: 2px;
}

.reader-ctrl--font {
  font-family:
    -apple-system, BlinkMacSystemFont, "SF Pro Text", "Inter", system-ui,
    sans-serif;
  font-weight: 600;
  color: rgba(255, 255, 255, 0.85);
}

.font-label {
  line-height: 1;
}

.font-label--small {
  font-size: 13px;
}

.font-label--large {
  font-size: 18px;
}

.reader-body {
  flex: 1 1 auto;
  overflow-y: auto;
  overflow-x: hidden;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: thin;
  scrollbar-color: rgba(255, 255, 255, 0.15) transparent;
  padding: 32px 24px 120px;
  outline: none;
}

.reader-body::-webkit-scrollbar {
  width: 6px;
}

.reader-body::-webkit-scrollbar-thumb {
  background: rgba(255, 255, 255, 0.15);
  border-radius: 3px;
}

.reader-content {
  max-width: 680px;
  margin: 0 auto;
  color: #d4d4d4;
  line-height: 1.65;
}

/* Font size steps — set on .reader-mode parent, inherited down */
.reader-mode--s .reader-content {
  font-size: 15px;
}
.reader-mode--m .reader-content {
  font-size: 18px;
}
.reader-mode--l .reader-content {
  font-size: 21px;
}
.reader-mode--xl .reader-content {
  font-size: 25px;
}

.reader-paragraph {
  margin: 0 0 1em;
  text-align: left;
  hyphens: auto;
  -webkit-hyphens: auto;
  overflow-wrap: break-word;
  word-wrap: break-word;
}

.reader-heading {
  font-family:
    -apple-system, BlinkMacSystemFont, "SF Pro Display", "Inter", system-ui,
    sans-serif;
  color: #f5f5f7;
  font-weight: 700;
  letter-spacing: -0.015em;
  margin: 2.2em 0 0.8em;
}

.reader-heading--l1 {
  font-size: 1.85em;
  margin-top: 3.2em;
  padding-top: 2em;
  letter-spacing: -0.02em;
  position: relative;
  text-align: center;
}

.reader-heading--l1::before {
  content: "";
  position: absolute;
  top: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 72px;
  height: 1px;
  background: rgba(255, 255, 255, 0.22);
}

.reader-heading--l1:first-child {
  margin-top: 0.4em;
  padding-top: 0;
}

.reader-heading--l1:first-child::before {
  display: none;
}

.reader-heading--l2 {
  font-size: 1.3em;
  margin-top: 1.8em;
  color: rgba(255, 255, 255, 0.88);
}

.reader-heading--l3 {
  font-size: 1.1em;
  margin-top: 1.4em;
  color: rgba(255, 255, 255, 0.75);
}

.reader-empty {
  max-width: 420px;
  margin: 60px auto 0;
  text-align: center;
  color: rgba(255, 255, 255, 0.5);
  font-size: 14px;
  line-height: 1.5;
}

body.reader-open {
  overflow: hidden;
}

/* ─── Mobile refinements ─────────────────────────────────────── */
@media (max-width: 768px) {
  #book-container {
    padding: 12px;
    padding-bottom: 80px;
  }
  .controls {
    bottom: 16px;
    padding: 8px 14px;
    gap: 10px;
  }
  .ctrl {
    width: 44px;
    height: 44px;
  }
  .page-indicator {
    min-width: 56px;
  }
  .toc-drawer {
    width: 100%;
  }
  .toc-drawer__header {
    padding: 18px 16px 14px 22px;
  }
  .toc-entry {
    padding-top: 12px;
    padding-bottom: 12px;
  }
}

/* Safe-area padding for notched devices */
@supports (padding: env(safe-area-inset-bottom)) {
  .controls {
    bottom: max(16px, env(safe-area-inset-bottom));
  }
  #book-container {
    padding-bottom: max(
      80px,
      calc(env(safe-area-inset-bottom) + 70px)
    );
  }
}