:root {
  --bg-0: #121416;
  --bg-1: #1a1c1e;
  --bg-2: #24272b;
  --ink: #f2efe8;
  --ink-muted: #9a958c;
  --accent: #d4a574;
  --accent-soft: rgba(212, 165, 116, 0.18);
  --line: rgba(242, 239, 232, 0.08);
  --shadow: 0 24px 80px rgba(0, 0, 0, 0.55);
  --radius: 14px;
  --topbar-h: 56px;
  --toolbar-h: 72px;
  --font-display: "Syne", sans-serif;
  --font-body: "Manrope", sans-serif;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  height: 100%;
  background:
    radial-gradient(1200px 700px at 50% -10%, #2a231c 0%, transparent 55%),
    radial-gradient(900px 500px at 100% 100%, #1c2428 0%, transparent 45%),
    var(--bg-0);
  color: var(--ink);
  font-family: var(--font-body);
  -webkit-font-smoothing: antialiased;
  overflow: hidden;
}

.app {
  display: grid;
  grid-template-rows: var(--topbar-h) 1fr var(--toolbar-h);
  height: 100%;
  height: 100dvh;
}

.topbar {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: 12px;
  padding: 0 16px;
  border-bottom: 1px solid var(--line);
  background: rgba(18, 20, 22, 0.72);
  backdrop-filter: blur(14px);
  z-index: 5;
}

.brand {
  display: inline-flex;
  align-items: center;
  text-decoration: none;
  max-width: 100%;
}

.brand-logo {
  display: block;
  height: 28px;
  width: auto;
  max-width: min(180px, 42vw);
  object-fit: contain;
  /* Koyu logo → açık zeminli arayüzde okunaklı */
  filter: brightness(0) invert(1);
}

.page-meta {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--ink-muted);
  text-align: center;
  white-space: nowrap;
}

.top-actions {
  display: flex;
  justify-content: flex-end;
  gap: 8px;
}

.icon-btn,
.nav-btn {
  appearance: none;
  border: 1px solid var(--line);
  background: var(--bg-2);
  color: var(--ink);
  cursor: pointer;
  transition: background 0.2s ease, border-color 0.2s ease, transform 0.15s ease;
}

.icon-btn {
  width: 36px;
  height: 36px;
  border-radius: 10px;
  display: grid;
  place-items: center;
  font-size: 1.15rem;
  line-height: 1;
}

.icon-btn:hover,
.nav-btn:hover {
  background: #2e3238;
  border-color: rgba(242, 239, 232, 0.16);
}

.icon-btn:active,
.nav-btn:active {
  transform: scale(0.96);
}

.stage {
  position: relative;
  display: grid;
  place-items: center;
  min-height: 0;
  padding: 12px 56px;
}

.book-wrap {
  width: min(1100px, 100%);
  height: 100%;
  display: grid;
  place-items: center;
  filter: drop-shadow(var(--shadow));
}

.flip-book {
  width: 100%;
  height: 100%;
}

.flip-book .page {
  background: #111;
  overflow: hidden;
}

.flip-book .page canvas {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: contain;
  background: #fff;
}

.page-placeholder {
  width: 100%;
  height: 100%;
  display: grid;
  place-items: center;
  background:
    linear-gradient(135deg, #f7f4ee 0%, #ebe6dc 100%);
  color: #8a847a;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 0.95rem;
  letter-spacing: 0.04em;
}

.nav-btn {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  z-index: 4;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  display: grid;
  place-items: center;
}

.nav-prev { left: 10px; }
.nav-next { right: 10px; }

.nav-btn:disabled {
  opacity: 0.35;
  cursor: default;
}

.toolbar {
  display: grid;
  gap: 8px;
  align-content: center;
  padding: 0 20px 10px;
  border-top: 1px solid var(--line);
  background: rgba(18, 20, 22, 0.72);
  backdrop-filter: blur(14px);
}

.page-slider {
  width: 100%;
  accent-color: var(--accent);
  cursor: pointer;
}

.hint {
  text-align: center;
  font-size: 0.78rem;
  color: var(--ink-muted);
}

.loader {
  position: fixed;
  inset: 0;
  z-index: 20;
  display: grid;
  place-items: center;
  background:
    radial-gradient(800px 480px at 50% 30%, #2a231c 0%, transparent 60%),
    var(--bg-0);
  transition: opacity 0.45s ease, visibility 0.45s ease;
}

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

.loader-card {
  width: min(360px, calc(100% - 40px));
  text-align: center;
}

.loader-logo {
  display: block;
  width: min(280px, 72vw);
  height: auto;
  margin: 0 auto 22px;
  object-fit: contain;
  filter: brightness(0) invert(1);
  animation: brandIn 0.7s ease both;
}

.loader-text {
  margin: 0 0 18px;
  color: var(--ink-muted);
  font-size: 0.95rem;
}

.progress {
  height: 4px;
  border-radius: 999px;
  background: var(--bg-2);
  overflow: hidden;
}

.progress-bar {
  height: 100%;
  width: 0%;
  border-radius: inherit;
  background: linear-gradient(90deg, #b8895a, var(--accent));
  transition: width 0.2s ease;
}

.loader-pct {
  margin: 10px 0 0;
  font-size: 0.8rem;
  color: var(--ink-muted);
  font-variant-numeric: tabular-nums;
}

@keyframes brandIn {
  from {
    opacity: 0;
    transform: translateY(10px) scale(0.98);
  }
  to {
    opacity: 1;
    transform: none;
  }
}

@media (max-width: 768px) {
  :root {
    --topbar-h: 52px;
    --toolbar-h: 64px;
  }

  .stage {
    padding: 8px 8px 4px;
  }

  .nav-btn {
    display: none;
  }

  .hint {
    display: none;
  }

  .topbar {
    padding: 0 12px;
  }

  .brand-logo {
    height: 24px;
    max-width: min(140px, 38vw);
  }

  .page-meta {
    font-size: 0.8rem;
  }
}

@media (prefers-reduced-motion: reduce) {
  .loader-logo,
  .icon-btn,
  .nav-btn,
  .loader,
  .progress-bar {
    animation: none;
    transition: none;
  }
}