:root {
  color-scheme: dark;
  --bg: #07070a;
  --surface: rgba(18, 18, 23, 0.82);
  --surface-strong: rgba(28, 28, 34, 0.92);
  --line: rgba(255, 255, 255, 0.12);
  --text: rgba(255, 255, 255, 0.92);
  --muted: rgba(255, 255, 255, 0.58);
  --accent: #8f63ff;
  --shadow: 0 24px 80px rgba(0, 0, 0, 0.5);
  --topbar-height: 64px;
  --page-max-width: 1360px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  background: var(--bg);
}

body {
  margin: 0;
  min-height: 100vh;
  background:
    radial-gradient(circle at 50% -10%, rgba(132, 81, 255, 0.2), transparent 32rem),
    linear-gradient(180deg, #09090d 0%, #050507 100%);
  color: var(--text);
  font-family:
    Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "SF Pro Text",
    "Helvetica Neue", Arial, "PingFang SC", "Hiragino Sans GB", sans-serif;
  letter-spacing: 0;
  -webkit-font-smoothing: antialiased;
}

button,
a {
  -webkit-tap-highlight-color: transparent;
}

button {
  font: inherit;
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 20;
  display: grid;
  grid-template-columns: minmax(max-content, 1fr) auto minmax(max-content, 1fr);
  align-items: center;
  gap: 1rem;
  height: var(--topbar-height);
  padding: 0 clamp(1rem, 3vw, 2rem);
  border-bottom: 1px solid var(--line);
  background: rgba(7, 7, 10, 0.72);
  backdrop-filter: blur(18px);
}

.brand {
  display: inline-flex;
  align-items: baseline;
  gap: 0.75rem;
  color: var(--text);
  text-decoration: none;
  white-space: nowrap;
}

.brand-name {
  font-size: 1rem;
  font-weight: 650;
}

.brand-meta {
  color: var(--muted);
  font-size: 0.82rem;
}

.controls {
  display: inline-flex;
  align-items: center;
  justify-self: end;
  gap: 0.55rem;
}

.section-tabs {
  display: inline-flex;
  align-items: center;
  justify-self: center;
  gap: 0.25rem;
  padding: 0.25rem;
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.045);
}

.section-tab {
  height: 2rem;
  padding: 0 0.9rem;
  border: 0;
  border-radius: 999px;
  background: transparent;
  color: var(--muted);
  cursor: pointer;
  font-size: 0.84rem;
  white-space: nowrap;
  transition:
    color 160ms ease,
    background 160ms ease;
}

.section-tab:hover,
.section-tab.is-active {
  background: rgba(143, 99, 255, 0.22);
  color: var(--text);
}

.icon-button,
.back-top {
  display: inline-grid;
  place-items: center;
  height: 2.25rem;
  min-width: 2.25rem;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--surface);
  color: var(--text);
  cursor: pointer;
  transition:
    transform 160ms ease,
    border-color 160ms ease,
    background 160ms ease;
}

.icon-button:hover,
.back-top:hover {
  transform: translateY(-1px);
  border-color: rgba(255, 255, 255, 0.28);
  background: var(--surface-strong);
}

.page-status {
  min-width: 4.5rem;
  color: var(--muted);
  font-size: 0.86rem;
  text-align: center;
  font-variant-numeric: tabular-nums;
}

.progress {
  position: sticky;
  top: var(--topbar-height);
  z-index: 19;
  height: 2px;
  background: rgba(255, 255, 255, 0.08);
}

.progress span {
  display: block;
  width: 0%;
  height: 100%;
  background: linear-gradient(90deg, var(--accent), rgba(255, 255, 255, 0.86));
  transform-origin: left center;
  transition: width 120ms linear;
}

.reader {
  width: min(100%, calc(var(--page-max-width) + clamp(1.5rem, 6vw, 5.5rem)));
  margin: 0 auto;
  padding: clamp(1rem, 2.5vw, 2.5rem) clamp(0.75rem, 3vw, 2.75rem) 6rem;
}

.page {
  width: min(100%, var(--page-max-width));
  scroll-margin-top: calc(var(--topbar-height) + 24px);
  margin: 0 auto clamp(1.25rem, 3vw, 2.5rem);
  opacity: 1;
  transform: translateY(0);
}

.page-frame {
  position: relative;
  overflow: hidden;
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: 10px;
  background: #111;
  box-shadow: var(--shadow);
}

.page img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: contain;
  user-select: none;
  -webkit-user-drag: none;
  pointer-events: none;
}

.page-number {
  display: block;
  margin: 0.65rem 0 0;
  color: var(--muted);
  font-size: 0.78rem;
  text-align: right;
  font-variant-numeric: tabular-nums;
}

.page-rail {
  position: fixed;
  right: 1rem;
  top: 50%;
  z-index: 18;
  transform: translateY(-50%);
}

.rail-track {
  display: grid;
  gap: 0.35rem;
  max-height: min(72vh, 34rem);
  padding: 0.5rem;
  overflow: auto;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: rgba(7, 7, 10, 0.58);
  backdrop-filter: blur(18px);
  scrollbar-width: none;
}

.rail-track::-webkit-scrollbar {
  display: none;
}

.rail-dot {
  display: grid;
  place-items: center;
  width: 1.9rem;
  height: 1.9rem;
  border: 0;
  border-radius: 999px;
  background: transparent;
  color: var(--muted);
  cursor: pointer;
  font-size: 0.72rem;
  font-variant-numeric: tabular-nums;
}

.rail-dot:hover,
.rail-dot.is-active {
  background: rgba(143, 99, 255, 0.22);
  color: var(--text);
}

.back-top {
  position: fixed;
  right: 1rem;
  bottom: 1rem;
  z-index: 21;
  min-width: 3.25rem;
  padding: 0 0.9rem;
  color: var(--muted);
  font-size: 0.78rem;
  opacity: 0;
  pointer-events: none;
}

.back-top.is-visible {
  opacity: 1;
  pointer-events: auto;
}

@media (max-width: 860px) {
  :root {
    --topbar-height: 100px;
  }

  .topbar {
    grid-template-columns: minmax(0, 1fr) auto;
    grid-template-rows: 48px 42px;
    gap: 0 0.75rem;
    padding: 0 0.85rem 0.45rem;
  }

  .brand {
    gap: 0.5rem;
  }

  .brand-meta {
    display: none;
  }

  .controls {
    grid-column: 2;
    grid-row: 1;
  }

  .section-tabs {
    grid-column: 1 / -1;
    grid-row: 2;
    justify-self: stretch;
    overflow-x: auto;
    scrollbar-width: none;
  }

  .section-tabs::-webkit-scrollbar {
    display: none;
  }

  .section-tab {
    flex: 1 0 auto;
    padding: 0 0.85rem;
  }

  .reader {
    padding: 0.75rem 0.65rem 5rem;
  }

  .page-frame {
    border-radius: 7px;
  }

  .page-rail {
    display: none;
  }
}

@media (max-width: 1600px) {
  .page-rail {
    display: none;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
  }
}