:root {
  --bg: #f5f2ec;
  --bg-panel: #ffffff;
  --ink: #1a1a1a;
  --ink-soft: #555;
  --accent: #8a6a3b;
  --accent-deep: #5e4520;
  --line: #e4ddd0;
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.06), 0 2px 8px rgba(0,0,0,0.04);
  --shadow-md: 0 4px 16px rgba(0,0,0,0.08), 0 8px 32px rgba(0,0,0,0.06);
  --radius: 10px;
  --font: "Georgia", "Times New Roman", serif;
  --font-ui: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font-ui);
  font-size: 15px;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
}

/* ===== Header ===== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: #fff;
  border-bottom: 1px solid var(--line);
  box-shadow: var(--shadow-sm);
}

.brand {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 14px 28px 10px;
  max-width: 1400px;
  margin: 0 auto;
}

.brand-mark {
  width: 44px;
  height: 44px;
  border-radius: 8px;
  background: linear-gradient(135deg, var(--accent) 0%, var(--accent-deep) 100%);
  color: #fff;
  display: grid;
  place-items: center;
  font-family: var(--font);
  font-weight: 700;
  font-size: 18px;
  letter-spacing: 0.5px;
}

.brand-title {
  font-family: var(--font);
  font-size: 22px;
  font-weight: 700;
  color: var(--ink);
  letter-spacing: 0.3px;
}
.brand-sub {
  font-size: 13px;
  color: var(--ink-soft);
}

/* ===== Tabs ===== */
.tabs {
  display: flex;
  gap: 6px;
  padding: 0 28px;
  max-width: 1400px;
  margin: 0 auto;
  overflow-x: auto;
}

.tab {
  appearance: none;
  border: none;
  background: transparent;
  padding: 12px 18px;
  font: inherit;
  font-size: 15px;
  font-weight: 500;
  color: var(--ink-soft);
  cursor: pointer;
  border-bottom: 3px solid transparent;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  white-space: nowrap;
  transition: color .15s ease, border-color .15s ease, background .15s ease;
  border-top-left-radius: 8px;
  border-top-right-radius: 8px;
}

.tab:hover { color: var(--ink); background: rgba(0,0,0,0.03); }
.tab[aria-selected="true"] {
  color: var(--accent-deep);
  border-bottom-color: var(--accent);
  font-weight: 600;
}

.tab-icon { font-size: 16px; }

/* ===== Main ===== */
.container {
  max-width: 1400px;
  margin: 0 auto;
  padding: 24px 28px 60px;
}

.panel { animation: fadeIn .25s ease; }
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(4px); }
  to { opacity: 1; transform: none; }
}

/* ===== Toolbar ===== */
.toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
  background: var(--bg-panel);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 14px 18px;
  margin-bottom: 10px;
  box-shadow: var(--shadow-sm);
}

.toolbar-title {
  font-family: var(--font);
  font-size: 18px;
  font-weight: 700;
  color: var(--ink);
}

.toolbar-actions {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

.btn {
  appearance: none;
  border: 1px solid var(--line);
  background: #fff;
  color: var(--ink);
  font: inherit;
  font-weight: 500;
  padding: 9px 14px;
  border-radius: 8px;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  transition: all .15s ease;
}
.btn:hover {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
  transform: translateY(-1px);
  box-shadow: var(--shadow-sm);
}
.btn:active { transform: none; }

.hint {
  font-size: 13px;
  color: var(--ink-soft);
  padding: 4px 4px 14px;
}
.hint-mobile { display: none; }
@media (max-width: 720px) {
  .hint-desktop { display: none; }
  .hint-mobile { display: inline; }
}

/* ===== PDF viewer ===== */
.pdf-viewer {
  display: flex;
  flex-direction: column;
  gap: 18px;
  align-items: center;
  min-height: 400px;
}

.pdf-page-wrap {
  display: flex;
  justify-content: center;
  width: 100%;
}

.pdf-page {
  position: relative;
  background: #fff;
  box-shadow: var(--shadow-md);
  border-radius: 4px;
  overflow: hidden;
  cursor: zoom-in;
  max-width: 100%;
  transition: transform .15s ease, box-shadow .15s ease;
}
.pdf-page:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 24px rgba(0,0,0,0.12), 0 12px 40px rgba(0,0,0,0.08);
}
.pdf-page canvas {
  display: block;
  max-width: 100%;
  height: auto;
}
.pdf-page-number {
  position: absolute;
  left: 12px;
  top: 12px;
  background: rgba(0,0,0,0.6);
  color: #fff;
  font-size: 12px;
  padding: 3px 8px;
  border-radius: 4px;
  opacity: 0;
  transition: opacity .15s ease;
  pointer-events: none;
}
.pdf-page:hover .pdf-page-number { opacity: 1; }

.pdf-loading {
  padding: 60px 20px;
  text-align: center;
  color: var(--ink-soft);
}
.spinner {
  display: inline-block;
  width: 28px;
  height: 28px;
  border: 3px solid var(--line);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
  margin-bottom: 10px;
}
@keyframes spin { to { transform: rotate(360deg); } }

.pdf-error {
  padding: 40px 20px;
  text-align: center;
  color: #a33;
  background: #fff3f3;
  border-radius: var(--radius);
  border: 1px solid #f2d6d6;
}

/* ===== Lightbox ===== */
.lightbox {
  position: fixed;
  inset: 0;
  background: #0a0a0a;
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: center;
  animation: fadeIn .2s ease;
}
.lightbox[hidden] { display: none !important; }

.lightbox-stage {
  width: 94vw;
  height: 86vh;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: auto;
  -webkit-overflow-scrolling: touch;
  cursor: zoom-in;
}
.lightbox-stage img {
  max-width: 100%;
  max-height: 100%;
  width: auto;
  height: auto;
  object-fit: contain;
  box-shadow: 0 20px 80px rgba(0,0,0,0.6);
  background: #fff;
  user-select: none;
  -webkit-user-drag: none;
}
.lightbox-stage.zoomed {
  cursor: zoom-out;
  align-items: flex-start;
  justify-content: flex-start;
}
.lightbox-stage.zoomed img {
  max-width: none;
  max-height: none;
  width: 200%;
  height: auto;
}

.lightbox-close {
  position: absolute;
  top: 16px;
  right: 20px;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  border: none;
  background: rgba(255,255,255,0.1);
  color: #fff;
  font-size: 28px;
  line-height: 1;
  cursor: pointer;
  display: grid;
  place-items: center;
  transition: background .15s ease, transform .15s ease;
}
.lightbox-close:hover {
  background: rgba(255,255,255,0.25);
  transform: scale(1.08);
}

.lightbox-nav {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  width: 54px;
  height: 54px;
  border-radius: 50%;
  border: none;
  background: rgba(255,255,255,0.1);
  color: #fff;
  font-size: 36px;
  line-height: 1;
  cursor: pointer;
  display: grid;
  place-items: center;
  transition: background .15s ease, transform .15s ease;
}
.lightbox-nav:hover {
  background: rgba(255,255,255,0.25);
}
.lightbox-prev { left: 20px; }
.lightbox-next { right: 20px; }
.lightbox-nav:disabled { opacity: 0.25; cursor: default; }
.lightbox-nav:disabled:hover { background: rgba(255,255,255,0.1); }

.lightbox-caption {
  position: absolute;
  bottom: 20px;
  left: 50%;
  transform: translateX(-50%);
  color: rgba(255,255,255,0.85);
  font-size: 14px;
  background: rgba(0,0,0,0.4);
  padding: 6px 14px;
  border-radius: 20px;
  max-width: 80vw;
  text-align: center;
}

/* ===== Footer ===== */
.site-footer {
  border-top: 1px solid var(--line);
  background: #fff;
  padding: 18px 28px;
  color: var(--ink-soft);
  font-size: 13px;
  text-align: center;
}

/* ===== Mobile ===== */
@media (max-width: 720px) {
  .brand { padding: 12px 16px 8px; }
  .brand-title { font-size: 18px; }
  .brand-sub { font-size: 12px; }
  .tabs { padding: 0 16px; }
  .tab { padding: 10px 12px; font-size: 14px; }
  .container { padding: 16px 0 40px; }
  .toolbar { padding: 12px 14px; margin: 0 12px 10px; }
  .toolbar-title { font-size: 16px; }
  .btn { padding: 8px 12px; font-size: 14px; }
  .hint { padding: 4px 12px 14px; }

  /* PDF viewer on mobile: each page fits the screen width.
     To read small text, tap the page to zoom it in the lightbox. */
  .pdf-viewer {
    padding: 0;
    gap: 14px;
    align-items: stretch;
  }
  .pdf-page-wrap {
    width: 100%;
    padding: 0 12px;
    justify-content: center;
  }
  .pdf-page {
    max-width: 100%;
    border-radius: 6px;
  }
  .pdf-page canvas {
    width: 100% !important;
    height: auto !important;
    max-width: 100%;
    display: block;
  }

  .lightbox-nav { display: none; } /* on mobile use swipe / buttons in caption */
  .lightbox-close { top: 10px; right: 10px; width: 40px; height: 40px; font-size: 26px; z-index: 3; }
  .lightbox-caption { bottom: 10px; font-size: 12px; padding: 5px 10px; }
}