/* ── Reset & Tokens ── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg:        #0d0d0f;
  --bg-card:   #141416;
  --surface:   #1c1c20;
  --border:    rgba(255,255,255,.07);
  --text:      #e8e8ec;
  --text-muted:#7a7a8a;
  --accent:    #a78bfa;
  --accent-dim:#6d5fa0;
  --header-h:  56px;
  --radius:    8px;
  --font:      'Inter', system-ui, sans-serif;
  --shadow:    0 4px 32px rgba(0,0,0,.55);
}

html { scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  font-size: 14px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

/* ── Scrollbar ── */
::-webkit-scrollbar { width: 5px; }
::-webkit-scrollbar-track { background: var(--bg); }
::-webkit-scrollbar-thumb { background: var(--surface); border-radius: 99px; }
::-webkit-scrollbar-thumb:hover { background: var(--accent-dim); }

/* ── Header ── */
#site-header {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  background: rgba(13,13,15,.88);
  backdrop-filter: blur(18px) saturate(160%);
  -webkit-backdrop-filter: blur(18px) saturate(160%);
  border-bottom: 1px solid var(--border);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--header-h);
  padding: 0 24px;
  max-width: 1400px;
  margin: 0 auto;
}

.logo {
  font-size: 15px;
  font-weight: 600;
  letter-spacing: -.01em;
  color: var(--text);
}

.nav-info {
  display: flex;
  align-items: center;
  gap: 20px;
}

.page-counter {
  font-size: 12px;
  color: var(--text-muted);
  font-variant-numeric: tabular-nums;
  letter-spacing: .04em;
}

.btn-dl {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 7px 14px;
  background: transparent;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--text-muted);
  text-decoration: none;
  font-size: 12px;
  font-weight: 500;
  letter-spacing: .02em;
  transition: all .2s ease;
}
.btn-dl:hover {
  border-color: var(--accent);
  color: var(--accent);
  background: rgba(167,139,250,.06);
}
.btn-dl .icon {
  width: 14px;
  height: 14px;
  flex-shrink: 0;
}

/* ── Progress bar ── */
.progress-bar {
  height: 2px;
  background: var(--border);
  position: relative;
}
.progress-fill {
  height: 100%;
  width: 0%;
  background: linear-gradient(90deg, var(--accent-dim), var(--accent));
  transition: width .12s linear;
  border-radius: 0 2px 2px 0;
}

/* ── Main / PDF container ── */
#pdf-container {
  margin-top: var(--header-h);
  padding: 40px 20px 60px;
  min-height: 100vh;
}

/* ── Loading ── */
#loading-screen {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 20px;
  min-height: 60vh;
  color: var(--text-muted);
  font-size: 13px;
}

.spinner {
  width: 36px;
  height: 36px;
  border: 2px solid var(--border);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin .7s linear infinite;
}

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

/* ── Slides wrapper ── */
#slides-wrapper {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 24px;
  max-width: 1600px;
  margin: 0 auto;
}

/* ── Slide item ── */
.slide-item {
  position: relative;
  width: 100%;
  border-radius: var(--radius);
  overflow: hidden;
  background: var(--bg-card);
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
  transition: box-shadow .3s ease, transform .3s ease;
  /* fade-in on scroll */
  opacity: 0;
  transform: translateY(16px);
  transition: opacity .5s ease, transform .5s ease, box-shadow .3s ease;
}

.slide-item.visible {
  opacity: 1;
  transform: translateY(0);
}

.slide-item:hover {
  box-shadow: 0 8px 48px rgba(0,0,0,.7), 0 0 0 1px rgba(167,139,250,.12);
}

.slide-item canvas,
.slide-item img {
  display: block;
  width: 100%;
  height: auto;
}

/* link annotation overlay */
.slide-item .link-layer {
  position: absolute;
  top: 0; left: 0;
  width: 100%; height: 100%;
  pointer-events: none; /* children will get pointer-events */
}

.link-overlay {
  position: absolute;
  cursor: pointer;
  pointer-events: all;
  border-radius: 2px;
  transition: background .15s ease;
}
.link-overlay:hover {
  background: rgba(167,139,250,.15);
  outline: 1px solid rgba(167,139,250,.4);
}

/* slide number badge */
.slide-number {
  position: absolute;
  bottom: 10px;
  right: 14px;
  font-size: 11px;
  color: var(--text-muted);
  opacity: .5;
  pointer-events: none;
  user-select: none;
  font-variant-numeric: tabular-nums;
}

/* ── Footer ── */
#site-footer {
  text-align: center;
  padding: 32px 20px;
  color: var(--text-muted);
  font-size: 12px;
  border-top: 1px solid var(--border);
  letter-spacing: .04em;
}

/* ── Responsive ── */
@media (max-width: 768px) {
  #pdf-container { padding: 28px 12px 48px; }
  #slides-wrapper { gap: 16px; }
  .logo { font-size: 13px; }
  .btn-dl span { display: none; }
}

@media (max-width: 480px) {
  .header-inner { padding: 0 14px; }
  .btn-dl { padding: 7px 10px; }
}