:root {
  --red: #d62e3e;
  --red-dark: #b91f2e;
  --gold: #e8b23d;
  --gold-light: #fff8e8;
  --jade: #1e7a5f;
  --ink: #0a1e38;
  --bg: #102a4c;
  --surface-hover: rgba(16, 42, 76, .08);
  --border: #ecdfc4;
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
  --font-display: "Manrope", ui-sans-serif, system-ui, sans-serif;
  --font-body: "Be Vietnam Pro", ui-sans-serif, system-ui, sans-serif;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: var(--font-body);
  background-color: var(--bg);
  background-image:
    linear-gradient(135deg, rgba(232, 178, 61, 0.06) 1px, transparent 1px),
    linear-gradient(45deg, rgba(232, 178, 61, 0.06) 1px, transparent 1px);
  background-size: 26px 26px;
  color: #fff;
  -webkit-font-smoothing: antialiased;
}

a, button { text-decoration: none; color: inherit; transition: color .2s var(--ease), background-color .2s var(--ease), border-color .2s var(--ease), transform .15s var(--ease), box-shadow .2s var(--ease), opacity .2s var(--ease); }
button:not(:disabled):active, a:active { transform: scale(0.96); }

/* ---------- Header ---------- */
.topbar {
  background: var(--ink);
  color: #fff;
  position: sticky;
  top: 0;
  z-index: 30;
  box-shadow: 0 2px 14px rgba(0,0,0,.15);
}
.topbar::after {
  content: "";
  display: block;
  height: 3px;
  background: linear-gradient(90deg, var(--gold) 0%, var(--red) 65%, var(--red-dark) 100%);
}
.topbar-inner {
  max-width: 1600px;
  margin: 0 auto;
  padding: 14px 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  flex-wrap: wrap;
}
.brand {
  display: flex;
  align-items: center;
  gap: 12px;
}
.brand:hover .brand-mark { transform: scale(1.05); }
.brand-mark {
  height: 42px;
  width: auto;
  border-radius: 8px;
  transition: transform .3s var(--ease);
  box-shadow: 0 2px 10px rgba(0,0,0,.2);
}
.brand-name {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 16px;
  color: #fff;
  letter-spacing: -0.005em;
  line-height: 1.2;
}
@media (max-width: 560px) {
  .brand-name { display: none; }
}

.topbar-actions { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; }

.btn-contact {
  background: var(--red);
  color: #fff;
  font-weight: 700;
  font-size: 13.5px;
  padding: 10px 18px;
  border-radius: 999px;
  box-shadow: 0 4px 14px rgba(214,46,62,.35);
}
.btn-contact:hover { background: var(--red-dark); transform: translateY(-1px); box-shadow: 0 6px 18px rgba(214,46,62,.45); }

.icon-link {
  position: relative;
  width: 36px;
  height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 999px;
  background: rgba(255,255,255,.08);
}
.icon-link:hover { background: rgba(255,255,255,.16); transform: translateY(-1px); }
.icon-zalo { width: 36px; height: 36px; fill: #0068ff; }
.zalo-letter { position: absolute; font-weight: 800; font-size: 14px; color: #fff; }
.phone-link {
  font-weight: 700;
  font-size: 13.5px;
  color: var(--gold-light);
  padding: 9px 4px;
}
.phone-link:hover { color: #fff; }

/* ---------- Viewer ---------- */
.viewer-wrap {
  max-width: 1600px;
  margin: 0 auto;
  padding: 24px 16px 56px;
}

.controls-row {
  max-width: 1040px;
  margin: 0 auto 18px;
}

.doc-tabs {
  display: flex;
  gap: 8px;
  margin-bottom: 14px;
  flex-wrap: wrap;
  justify-content: center;
}
.doc-tab {
  border: 1.5px solid var(--border);
  background: #fff;
  color: rgba(42,30,26,.6);
  font-family: var(--font-body);
  font-size: 13.5px;
  font-weight: 600;
  padding: 10px 18px;
  border-radius: 999px;
  cursor: pointer;
}
.doc-tab:hover { border-color: var(--gold); color: var(--ink); }
.doc-tab.is-active {
  background: var(--red);
  border-color: var(--red);
  color: #fff;
  box-shadow: 0 4px 14px rgba(214,46,62,.3);
}

.toolbar {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
  gap: 8px;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 7px 10px;
  box-shadow: 0 2px 10px rgba(42,30,26,.06);
}
.toolbar-group { display: flex; align-items: center; gap: 6px; }
.toolbar-divider { width: 1px; height: 22px; background: var(--border); margin: 0 4px; }
.tool-btn {
  width: 32px;
  height: 32px;
  border-radius: 999px;
  border: none;
  background: transparent;
  color: var(--ink);
  font-size: 17px;
  line-height: 1;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
}
.tool-btn:hover:not(:disabled) { background: var(--surface-hover); color: var(--red); }
.tool-btn:disabled { opacity: .3; cursor: default; }
.tool-btn-text { width: auto; padding: 0 14px; font-size: 12.5px; font-weight: 700; border-radius: 999px; }
.tool-btn-text:hover { background: var(--gold-light); color: var(--red-dark); }
.page-counter, .zoom-level {
  font-family: var(--font-body);
  font-size: 13px;
  font-variant-numeric: tabular-nums;
  font-weight: 600;
  color: rgba(42,30,26,.7);
  min-width: 54px;
  text-align: center;
}

.page-stage {
  position: relative;
  display: flex;
  align-items: flex-start;
  justify-content: center;
  padding: 8px 0;
  min-height: 60vh;
}
.page-frame { width: 100%; max-width: 1300px; display: flex; justify-content: center; }
#pageImage {
  max-width: 100%;
  width: 100%;
  height: auto;
  border-radius: 6px;
  box-shadow: 0 20px 50px -12px rgba(42,30,26,.28);
  transform-origin: center top;
  transition: transform .25s var(--ease), opacity .2s var(--ease);
  user-select: none;
  opacity: 1;
}
#pageImage.is-loading { opacity: 0; }

.nav-arrow {
  position: sticky;
  top: 45%;
  flex-shrink: 0;
  width: 46px;
  height: 46px;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: #fff;
  font-size: 20px;
  cursor: pointer;
  box-shadow: 0 6px 18px rgba(42,30,26,.12);
  z-index: 2;
}
.nav-arrow:hover:not(:disabled) { background: var(--red); color: #fff; border-color: var(--red); transform: translateY(-1px); }
.nav-arrow:disabled { opacity: .25; cursor: default; }
.nav-arrow-left { margin-right: -23px; }
.nav-arrow-right { margin-left: -23px; }
@media (max-width: 640px) {
  .nav-arrow { display: none; }
  .toolbar-divider { display: none; }
}

.thumb-strip {
  display: flex;
  gap: 10px;
  overflow-x: auto;
  padding: 22px 4px 4px;
  scrollbar-width: thin;
  justify-content: flex-start;
}
.thumb-item {
  flex-shrink: 0;
  width: 72px;
  border-radius: 9px;
  overflow: hidden;
  border: 2px solid transparent;
  cursor: pointer;
  opacity: .55;
  box-shadow: 0 2px 8px rgba(42,30,26,.08);
}
.thumb-item img { display: block; width: 100%; }
.thumb-item.is-active { border-color: var(--red); opacity: 1; transform: translateY(-2px); box-shadow: 0 6px 16px rgba(214,46,62,.25); }
.thumb-item:hover { opacity: 1; transform: translateY(-2px); }

/* ---------- Footer ---------- */
.site-footer {
  text-align: center;
  font-size: 12px;
  color: rgba(255,255,255,.4);
  padding: 24px;
}