/* ==========================================================================
   PHÒNG THI 24/7 — LEICA CINEMA & WETZLAR RANGEFINDER DESIGN SYSTEM
   Aesthetic: Leica M11 Monochrom · Criterion Collection · Swiss Photobook
   Palette:   Baryta Warm Paper (#F4F2EC) · Anodized Matte Black (#111110)
              Silver Chrome (#787670) · Leica Red Dot Accent (#D91E18)
   Typography: Newsreader / Playfair Display (Cinema Serif) + Be Vietnam Pro
               + JetBrains Mono (Aperture / Shutter Engraving Numerals)
   ========================================================================== */
:root {
  --primary: #111110;
  --primary-dark: #000000;
  --primary-ink: #111110;
  --primary-soft: #EAE7DF;
  --primary-border: #C9C5B9;
  --leica-red: #D91E18;
  --leica-red-soft: rgba(217, 30, 24, 0.08);
  --leica-red-border: rgba(217, 30, 24, 0.28);
  --accent: #D91E18;
  --ok: #166534;
  --ok-soft: #ECFDF3;
  --ok-border: #ABEFC6;
  --warn: #9A5B13;
  --warn-soft: #FDF6EC;
  --warn-border: #EDD6B4;
  --danger: #D91E18;
  --danger-soft: #FEF2F2;
  --danger-border: #F5C2C2;
  --bg: #F4F2EC;
  --card: #FAF9F5;
  --card-subtle: #EDEAE2;
  --ink: #111110;
  --ink-secondary: #383734;
  --muted: #6E6C66;
  --line: #DFDCD2;
  --line-strong: #C4C0B4;
  --r-xl: 6px;
  --r-lg: 4px;
  --r-md: 3px;
  --r-sm: 2px;
  --sh-card: 0 1px 0 rgba(17, 17, 16, 0.04), 0 8px 24px -12px rgba(17, 17, 16, 0.07);
  --sh-hover: 0 14px 34px -12px rgba(17, 17, 16, 0.14);
  --sh-pop: 0 28px 64px -16px rgba(17, 17, 16, 0.32);
  --font-serif: "Newsreader", "Playfair Display", Georgia, "Times New Roman", serif;
  --font-head: "Plus Jakarta Sans", "Be Vietnam Pro", -apple-system, sans-serif;
  --font-body: "Be Vietnam Pro", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --font-mono: "JetBrains Mono", Consolas, monospace;
}

html[data-theme="dark"] {
  --primary: #F4F2EC;
  --primary-dark: #FFFFFF;
  --primary-ink: #F4F2EC;
  --primary-soft: #222220;
  --primary-border: #3A3936;
  --leica-red: #E52520;
  --leica-red-soft: rgba(229, 37, 32, 0.14);
  --leica-red-border: rgba(229, 37, 32, 0.38);
  --accent: #E52520;
  --ok: #34D399;
  --ok-soft: rgba(52, 211, 153, 0.12);
  --ok-border: rgba(52, 211, 153, 0.3);
  --warn: #FBBF24;
  --warn-soft: rgba(251, 191, 36, 0.12);
  --warn-border: rgba(251, 191, 36, 0.3);
  --danger: #F87171;
  --danger-soft: rgba(248, 113, 113, 0.12);
  --danger-border: rgba(248, 113, 113, 0.3);
  --bg: #0D0D0C;
  --card: #151514;
  --card-subtle: #1E1E1C;
  --ink: #F4F2EC;
  --ink-secondary: #C8C5BC;
  --muted: #8A877F;
  --line: #262624;
  --line-strong: #3A3935;
  --sh-card: 0 1px 0 rgba(255, 255, 255, 0.03), 0 10px 28px -12px rgba(0, 0, 0, 0.65);
  --sh-hover: 0 18px 40px -12px rgba(0, 0, 0, 0.85);
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  font-family: var(--font-body);
  background: var(--bg);
  color: var(--ink);
  font-size: 15px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
::selection { background: var(--leica-red); color: #FFFFFF; }
:focus-visible { outline: 1.5px solid var(--leica-red); outline-offset: 2px; }
a { color: var(--ink); text-decoration: underline; text-underline-offset: 3px; text-decoration-color: var(--line-strong); transition: all .15s ease; }
a:hover { color: var(--leica-red); text-decoration-color: var(--leica-red); }
h1, h2, h3, h4 {
  font-family: var(--font-head);
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.25;
  margin: 0 0 10px;
  color: var(--ink);
}
.container { max-width: 1180px; margin: 0 auto; padding: 28px 22px; }

/* ---------- Top Navigation Bar (Leica Matte Black Chassis) ---------- */
.site-head {
  position: sticky;
  top: 0;
  z-index: 45;
  color: #F4F2EC;
  padding: 13px 22px;
  background: #111110;
  border-bottom: 1px solid #262624;
}
.site-head .container { padding-top: 0; padding-bottom: 0; }
.site-head .brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-serif);
  font-weight: 600;
  font-size: 21px;
  letter-spacing: -0.01em;
  color: #F4F2EC;
}
.leica-dot {
  display: inline-block;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: #D91E18;
  box-shadow: 0 0 10px rgba(217, 30, 24, 0.55);
  flex: none;
}
.site-head .sub {
  color: #8E8B82;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  margin-top: 2px;
}
.site-head .btn-ghost {
  color: #D6D3CA;
  border-color: #2E2E2B;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.03em;
  text-transform: uppercase;
}
.site-head .btn-ghost:hover {
  background: #1F1F1D;
  color: #FFFFFF;
  border-color: #D91E18;
}

/* ---------- Cards & Leica Contact-Sheet Frames (Cinematic Smooth Motion) ---------- */
@keyframes leicaFocusIn {
  0% {
    opacity: 0;
    transform: translateY(12px) scale(0.992);
    filter: blur(4px);
  }
  100% {
    opacity: 1;
    transform: translateY(0) scale(1);
    filter: blur(0);
  }
}

@keyframes leicaFrameAdvance {
  0% {
    opacity: 0.25;
    transform: translateY(6px);
    filter: blur(2px);
  }
  100% {
    opacity: 1;
    transform: translateY(0);
    filter: blur(0);
  }
}

.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  padding: 24px;
  margin-bottom: 16px;
  box-shadow: var(--sh-card);
  transition: border-color 0.35s cubic-bezier(0.16, 1, 0.3, 1), box-shadow 0.35s cubic-bezier(0.16, 1, 0.3, 1), background-color 0.3s ease;
}
.exam-card {
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition:
    transform 0.45s cubic-bezier(0.16, 1, 0.3, 1),
    border-color 0.35s cubic-bezier(0.16, 1, 0.3, 1),
    box-shadow 0.45s cubic-bezier(0.16, 1, 0.3, 1);
  padding: 22px 24px;
  border-radius: var(--r-lg);
  position: relative;
  animation: leicaFocusIn 0.55s cubic-bezier(0.16, 1, 0.3, 1) backwards;
}
.exam-card::after {
  content: "";
  position: absolute;
  top: 0;
  left: 24px;
  width: 64px;
  height: 2px;
  background: var(--leica-red);
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform 0.45s cubic-bezier(0.16, 1, 0.3, 1);
}
.exam-card:hover {
  border-color: var(--ink);
  box-shadow: var(--sh-hover);
  transform: translateY(-4px);
}
.exam-card:hover::after {
  transform: scaleX(1);
}
.exam-card-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 12px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--line);
}
.subj-code {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink);
}
.subj-code::before {
  content: "";
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--leica-red);
}
.exam-card h3 {
  font-family: var(--font-serif);
  font-size: 21px;
  font-weight: 600;
  letter-spacing: -0.015em;
  margin: 2px 0 8px;
  line-height: 1.32;
  color: var(--ink);
}
.exam-card .meta { display: flex; gap: 6px; flex-wrap: wrap; }

/* Aperture-Scale Mastery Meter */
.mastery-wrap {
  margin: 14px 0 16px;
  padding: 10px 12px;
  background: var(--card-subtle);
  border: 1px solid var(--line);
  border-radius: var(--r-md);
}
.mastery-head {
  display: flex;
  justify-content: space-between;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.03em;
  text-transform: uppercase;
  color: var(--ink-secondary);
  margin-bottom: 7px;
  font-variant-numeric: tabular-nums;
}
.mastery-bar {
  height: 3px;
  background: var(--line-strong);
  overflow: hidden;
}
.mastery-fill {
  height: 100%;
  background: var(--leica-red);
  transition: width .35s ease;
}

/* ---------- Buttons (Leica Machined Brass Controls) ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  background: var(--card);
  color: var(--ink);
  border: 1px solid var(--line-strong);
  border-radius: var(--r-md);
  padding: 8px 14px;
  font-size: 12.5px;
  font-weight: 600;
  font-family: var(--font-body);
  letter-spacing: 0.01em;
  cursor: pointer;
  text-decoration: none !important;
  transition: all .14s ease;
}
.btn:hover { background: var(--card-subtle); border-color: var(--ink); color: var(--ink); }
.btn-primary {
  background: var(--primary);
  color: var(--card) !important;
  border-color: var(--primary);
}
.btn-primary:hover {
  background: var(--leica-red);
  color: #FFFFFF !important;
  border-color: var(--leica-red);
}
.btn-danger {
  background: var(--leica-red);
  color: #FFFFFF !important;
  border-color: var(--leica-red);
}
.btn-danger:hover { filter: brightness(0.9); }
.btn-ghost {
  background: transparent;
  border: 1px solid var(--line);
  color: var(--ink-secondary);
}
.btn-ghost:hover { background: var(--card-subtle); border-color: var(--ink); color: var(--ink); }
.btn:disabled { opacity: .38; cursor: not-allowed; }
.btn svg { flex: none; }

/* ---------- Form Controls ---------- */
.field { margin-bottom: 14px; }
.field label {
  display: block;
  font-family: var(--font-mono);
  font-weight: 600;
  font-size: 11.5px;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--ink-secondary);
  margin-bottom: 6px;
}
input[type=text], input[type=number], input[type=password], select, textarea {
  width: 100%;
  padding: 9.5px 12px;
  border: 1px solid var(--line-strong);
  border-radius: var(--r-sm);
  font-size: 14px;
  font-family: inherit;
  background: var(--card);
  color: var(--ink);
  transition: border-color .14s ease;
}
input[type=checkbox], input[type=radio] { accent-color: var(--leica-red); width: 15px; height: 15px; }
input:focus, select:focus, textarea:focus {
  outline: none;
  border-color: var(--ink);
}
textarea { min-height: 92px; resize: vertical; }
.hint { font-size: 13px; color: var(--muted); line-height: 1.58; }
.err { color: var(--leica-red); font-size: 13px; font-weight: 600; }
.ok-msg { color: var(--ok); }
.gray { color: var(--muted); }

/* ---------- Banners ---------- */
.banner {
  padding: 12px 15px;
  border-radius: var(--r-md);
  margin-bottom: 14px;
  font-size: 13.5px;
  border: 1px solid var(--line-strong);
  background: var(--card-subtle);
  color: var(--ink-secondary);
  line-height: 1.6;
}
.banner-info { background: var(--card-subtle); border-color: var(--line-strong); color: var(--ink); }
.banner-warn { background: var(--warn-soft); border-color: var(--warn-border); color: var(--warn); }
.banner-danger { background: var(--danger-soft); border-color: var(--danger-border); color: var(--danger); }

/* ---------- Layout & Tables ---------- */
.grid2 { display: grid; grid-template-columns: repeat(auto-fit, minmax(350px, 1fr)); gap: 18px; }
.grid3 { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 16px; }
.row { display: flex; gap: 8px; align-items: center; flex-wrap: wrap; }
.spacer { flex: 1; }
table { width: 100%; border-collapse: collapse; font-size: 13.5px; font-variant-numeric: tabular-nums; }
th, td { padding: 9px 12px; border-bottom: 1px solid var(--line); text-align: left; vertical-align: top; color: var(--ink); }
th { background: var(--card-subtle); font-family: var(--font-mono); font-weight: 600; color: var(--ink-secondary); border-bottom: 1px solid var(--line-strong); font-size: 11.5px; text-transform: uppercase; letter-spacing: 0.04em; }
tbody tr:hover td { background: var(--card-subtle); }
.num { text-align: right; font-variant-numeric: tabular-nums; }
.badge {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  background: var(--card-subtle);
  border: 1px solid var(--line);
  border-radius: 2px;
  padding: 2px 8px;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.03em;
  color: var(--ink-secondary);
  font-variant-numeric: tabular-nums;
}

/* ==========================================================================
   EXAM WORKSTATION (LEICA RANGEFINDER VIEWFINDER)
   ========================================================================== */
.exam-head {
  position: sticky;
  top: 0;
  z-index: 50;
  color: #F4F2EC;
  padding: 10px 22px;
  display: flex;
  gap: 12px;
  align-items: center;
  flex-wrap: wrap;
  background: #111110;
  border-bottom: 1px solid #262624;
}
.exam-head strong { font-family: var(--font-serif); font-weight: 600; font-size: 16px; color: #F4F2EC; }
.exam-head .timer {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-weight: 700;
  font-size: 13.5px;
  background: #1C1C1A;
  border: 1px solid #333330;
  border-radius: 3px;
  padding: 4px 10px;
  color: #F4F2EC;
}
.exam-head .timer.low { background: #3B1010; color: #F87171; border-color: #D91E18; animation: pulse 1s infinite; }
@keyframes pulse { 50% { opacity: .55; } }

.top-progress-track {
  position: sticky;
  top: 52px;
  z-index: 49;
  height: 2px;
  background: var(--line);
  width: 100%;
}
.top-progress-Bar {
  height: 100%;
  background: var(--leica-red);
  width: 0%;
  transition: width .2s ease;
}

.exam-workstation {
  max-width: 1280px;
  margin: 0 auto;
  padding: 22px;
  display: grid;
  grid-template-columns: minmax(0, 1fr) 310px;
  gap: 22px;
  align-items: start;
}
.exam-main-col { min-width: 0; }
.exam-side-col {
  position: sticky;
  top: 74px;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  padding: 16px;
  box-shadow: var(--sh-card);
  max-height: calc(100vh - 94px);
  display: flex;
  flex-direction: column;
}

.side-stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 6px;
  margin-bottom: 10px;
  text-align: center;
}
.side-stat-box {
  background: var(--card-subtle);
  border: 1px solid var(--line);
  border-radius: 3px;
  padding: 6px 4px;
}
.side-stat-box b { display: block; font-size: 14px; font-family: var(--font-mono); color: var(--ink); }
.side-stat-box span { font-size: 10.5px; font-family: var(--font-mono); text-transform: uppercase; color: var(--muted); }

.palette-filter {
  display: flex;
  gap: 3px;
  margin-bottom: 10px;
  background: var(--card-subtle);
  padding: 3px;
  border-radius: 4px;
  border: 1px solid var(--line);
}
.pf-btn {
  flex: 1;
  border: none;
  background: transparent;
  color: var(--muted);
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 600;
  padding: 5px 4px;
  border-radius: 2px;
  cursor: pointer;
}
.pf-btn.active { background: var(--card); color: var(--ink); box-shadow: 0 1px 2px rgba(0,0,0,.06); }

.palette {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(38px, 1fr));
  gap: 5px;
  overflow-y: auto;
  padding-right: 2px;
  max-height: calc(100vh - 270px);
}
.palette button {
  height: 34px;
  padding: 0;
  border-radius: 3px;
  border: 1px solid var(--line);
  background: var(--card);
  cursor: pointer;
  font-size: 12px;
  font-weight: 600;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  color: var(--ink-secondary);
  position: relative;
}
.palette button:hover { border-color: var(--ink); color: var(--ink); }
.palette button.current {
  border: 1.5px solid var(--leica-red);
  background: var(--card-subtle);
  color: var(--ink);
  font-weight: 800;
}
.palette button.answered {
  background: var(--ink);
  color: var(--card);
  border-color: var(--ink);
}
.palette button.answered.current {
  background: var(--leica-red);
  border-color: var(--leica-red);
  color: #FFFFFF;
}
.palette button.flagged::after {
  content: "";
  position: absolute;
  top: 3px;
  right: 3px;
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--leica-red);
}

/* ---------- Anti-Copy & Question Workspace ---------- */
#examArea, #qView, .question, .option, .tfrow, .result-list, .van-sec {
  -webkit-user-select: none !important;
  -moz-user-select: none !important;
  -ms-user-select: none !important;
  user-select: none !important;
  -webkit-touch-callout: none !important;
}
input, textarea {
  -webkit-user-select: text !important;
  user-select: text !important;
}
.copy-toast {
  position: fixed;
  bottom: 20px;
  right: 20px;
  z-index: 120;
  background: #111110;
  color: #F4F2EC;
  border: 1px solid #333330;
  border-left: 3px solid var(--leica-red);
  padding: 9px 14px;
  border-radius: 4px;
  font-size: 13px;
  font-weight: 500;
  box-shadow: var(--sh-pop);
  pointer-events: none;
  opacity: 0;
  transform: translateY(8px);
  transition: opacity .18s ease, transform .18s ease;
}
.copy-toast.show { opacity: 1; transform: translateY(0); }

body.window-blurred #qView {
  filter: blur(12px);
  pointer-events: none;
  user-select: none;
}
.proctor-pip {
  position: fixed;
  bottom: 20px;
  left: 20px;
  width: 152px;
  height: 114px;
  border-radius: 4px;
  overflow: hidden;
  background: #111110;
  border: 1.5px solid var(--leica-red);
  box-shadow: var(--sh-pop);
  z-index: 85;
  display: none;
}
.proctor-pip.warn { border-color: var(--danger); animation: pulse 1s infinite; }
.proctor-pip video { width: 100%; height: 100%; object-fit: cover; transform: scaleX(-1); }
.proctor-badge {
  position: absolute;
  top: 6px;
  left: 6px;
  background: rgba(17, 17, 16, 0.85);
  color: #F4F2EC;
  font-size: 10px;
  font-family: var(--font-mono);
  font-weight: 700;
  padding: 2px 6px;
  border-radius: 2px;
  display: inline-flex;
  align-items: center;
  gap: 4px;
}
.proctor-dot { width: 6px; height: 6px; border-radius: 50%; background: #D91E18; }

#qView {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  padding: 26px 30px;
  box-shadow: var(--sh-card);
  animation: leicaFrameAdvance 0.32s cubic-bezier(0.16, 1, 0.3, 1);
}
#qView.frame-shift {
  animation: none;
}
.q-toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  padding-bottom: 12px;
  margin-bottom: 18px;
  border-bottom: 1px solid var(--line);
  flex-wrap: wrap;
}
.q-num-pill {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 12px;
  letter-spacing: 0.04em;
  background: var(--ink);
  color: var(--card);
  padding: 4px 10px;
  border-radius: 2px;
}
.question { color: var(--ink); font-size: 16px; line-height: 1.72; margin-bottom: 18px; max-width: 75ch; }

.option-wrap { display: flex; align-items: stretch; gap: 8px; margin: 9px 0; }
.option {
  flex: 1;
  display: flex;
  gap: 12px;
  align-items: flex-start;
  border: 1px solid var(--line-strong);
  border-radius: var(--r-md);
  padding: 12px 15px;
  cursor: pointer;
  background: var(--card);
  transition:
    transform 0.28s cubic-bezier(0.16, 1, 0.3, 1),
    border-color 0.22s ease,
    background-color 0.22s ease,
    box-shadow 0.28s cubic-bezier(0.16, 1, 0.3, 1);
}
.option:hover {
  border-color: var(--ink);
  background: var(--card-subtle);
  transform: translateX(3px);
}
.option.selected {
  border-color: var(--ink);
  background: var(--primary-soft);
  box-shadow: inset 3px 0 0 var(--leica-red);
}
.option b {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 25px;
  height: 25px;
  border-radius: 3px;
  background: var(--card-subtle);
  border: 1px solid var(--line-strong);
  color: var(--ink);
  font-family: var(--font-mono);
  font-size: 12px;
  flex: none;
}
.option.selected b {
  background: var(--leica-red);
  border-color: var(--leica-red);
  color: #FFFFFF;
}
.option.eliminated { opacity: 0.36; background: var(--card-subtle); }
.option.eliminated span { text-decoration: line-through; }
.strike-btn {
  width: 36px;
  border: 1px solid var(--line);
  background: var(--card);
  color: var(--muted);
  border-radius: var(--r-md);
  cursor: pointer;
  font-size: 12px;
  font-family: var(--font-mono);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  flex: none;
}
.strike-btn:hover { border-color: var(--ink); color: var(--ink); }
.strike-btn.active { background: var(--danger-soft); color: var(--leica-red); border-color: var(--leica-red-border); }

.tfrow {
  display: flex;
  gap: 12px;
  align-items: center;
  padding: 11px 14px;
  margin: 8px 0;
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  background: var(--card-subtle);
}
.tfbtn {
  min-width: 54px;
  padding: 6px 12px;
  border-radius: 3px;
  border: 1px solid var(--line-strong);
  background: var(--card);
  cursor: pointer;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 12.5px;
  color: var(--ink-secondary);
}
.tfbtn:hover { border-color: var(--ink); color: var(--ink); }
.tfbtn.sel-true { background: var(--ok); color: #FFFFFF; border-color: var(--ok); }
.tfbtn.sel-false { background: var(--leica-red); color: #FFFFFF; border-color: var(--leica-red); }
.short-input { max-width: 240px; font-size: 16px; font-weight: 700; font-family: var(--font-mono); text-align: center; }

.part-divider {
  margin: 0 0 14px;
  padding: 9px 12px;
  border-radius: var(--r-sm);
  background: var(--card-subtle);
  border: 1px solid var(--line);
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 12px;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--ink);
}

/* ---------- Results ---------- */
.result-list .q {
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  padding: 16px 18px;
  margin: 10px 0;
  background: var(--card);
  content-visibility: auto;
  contain-intrinsic-size: 0 180px;
}
.result-list .q.ok { border-color: var(--ok-border); }
.result-list .q.bad { border-color: var(--danger-border); }
.tag-ok { color: var(--ok); font-weight: 700; }
.tag-bad { color: var(--leica-red); font-weight: 700; }
.explain {
  background: var(--card-subtle);
  border: 1px solid var(--line);
  border-radius: 4px;
  padding: 10px 14px;
  margin-top: 10px;
  font-size: 13.5px;
  color: var(--ink-secondary);
}
img.qimg, img.qimg-inline { max-width: 100%; height: auto; }

footer {
  color: var(--muted);
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.04em;
  padding: 26px 16px 34px;
  text-align: center;
  border-top: 1px solid var(--line);
  margin-top: 40px;
  background: var(--card);
}
footer a { color: var(--ink-secondary); font-weight: 600; }

/* ---------- Modal ---------- */
.modal-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(17, 17, 16, 0.65);
  backdrop-filter: blur(3px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 90;
  padding: 16px;
}
.modal {
  background: var(--card);
  border: 1px solid var(--line-strong);
  border-radius: var(--r-xl);
  max-width: 460px;
  width: 100%;
  padding: 24px;
  box-shadow: var(--sh-pop);
}
.modal h3 { font-family: var(--font-serif); margin-top: 0; font-size: 20px; }

@media (max-width: 960px) {
  .exam-workstation { grid-template-columns: 1fr; }
  .exam-side-col { position: static; max-height: none; }
  .palette { max-height: 220px; }
}

@media (max-width: 560px) {
  .container, .exam-workstation { padding: 12px; }
  .card, #qView { padding: 16px; }
  .grid2 { grid-template-columns: 1fr; }
  .btn { padding: 7px 11px; font-size: 12px; }
}

@media print {
  body.exam-active * { display: none !important; }
  body.exam-active::after {
    content: "Phòng thi không cho phép in hoặc lưu bài đang làm – Phòng Thi 24/7";
    display: block; font-size: 20px; text-align: center; padding: 60px 20px; color: #991B1B;
  }
  body { background: #fff; color: #111; }
  .site-head, .exam-head, .exam-side-col, footer, .btn { display: none !important; }
  .card, .result-list .q, #qView { border: 1px solid #ccc; box-shadow: none; }
}

/* ==========================================================================
   PRE-EXAM CONFIG (thi.html) — stepped 4-section layout, clean hierarchy
   ========================================================================== */
.enter-head { padding: 20px 24px; }
.enter-head-row { display: flex; align-items: center; justify-content: space-between; gap: 12px; flex-wrap: wrap; }
.enter-brand { display: flex; align-items: center; gap: 12px; min-width: 0; }
.enter-brand h2 { margin: 0; }

.enter-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; align-items: start; }
.enter-sec { padding: 18px 22px; }
.enter-sec-title {
  display: flex; align-items: center; gap: 10px;
  font-family: var(--font-head); font-size: 15px; font-weight: 700;
  margin: 0 0 12px; color: var(--ink);
}
.enter-sec-title .hint { font-weight: 400; margin-left: auto; }
.step-num {
  display: inline-flex; align-items: center; justify-content: center;
  width: 22px; height: 22px; border-radius: 50%;
  background: var(--leica-red); color: #FFFFFF;
  font-family: var(--font-mono); font-size: 12px; font-weight: 700; flex: none;
}
.fgrid { display: grid; grid-template-columns: 1fr 1fr; gap: 0 14px; }

/* Mode options — vertical stack, roomy */
.mode-list { display: flex; flex-direction: column; gap: 8px; }
.mode-opt {
  border: 1.5px solid var(--line); border-radius: 10px; padding: 11px 14px;
  cursor: pointer; display: flex; gap: 10px; align-items: flex-start;
  background: var(--card); transition: all .15s ease;
}
.mode-opt:hover { border-color: var(--line-strong); background: var(--card-subtle); }
.mode-opt.active { border-color: var(--primary); background: var(--primary-soft); box-shadow: 0 0 0 1px var(--primary); }
.mode-opt input { margin-top: 3px; }
.mode-opt b { font-size: 13.5px; }
.mode-opt--compact { align-items: center; }
.mode-opt--compact b { font-size: 13px; }

/* Duration pills — grouped with tiny labels */
.dur-pills { display: flex; flex-direction: column; gap: 10px; }
.dur-group { display: flex; gap: 6px; flex-wrap: wrap; align-items: center; }
.dur-label {
  font-family: var(--font-mono); font-size: 10.5px; font-weight: 700;
  letter-spacing: .05em; text-transform: uppercase; color: var(--muted);
  margin-right: 4px; flex: none;
}
.dur-pill {
  border: 1px solid var(--line-strong); background: var(--card); color: var(--ink-secondary);
  border-radius: 8px; padding: 6px 12px; font-size: 13px; font-weight: 600;
  cursor: pointer; transition: all .14s ease;
}
.dur-pill:hover { border-color: var(--primary); color: var(--primary); }
.dur-pill.active { background: var(--primary); color: var(--card); border-color: var(--primary); }

.enter-actions { display: flex; gap: 10px; align-items: center; flex-wrap: wrap; margin-top: 18px; }
.btn-start { padding: 11px 24px; font-size: 15px; }
#headCode:empty { display: none; }

/* Exam topbar — cluster clock/timer/theme so they wrap together */
.head-cluster { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; }
.timer-cluster { display: flex; align-items: center; gap: 4px; }
.head-code { background: var(--leica-red); color: #FFFFFF; border-color: var(--leica-red); }

/* Bottom nav dock — sticks so Next/Prev never scrolls away (65-câu đề cương) */
.nav-dock {
  position: sticky;
  bottom: 14px;
  z-index: 40;
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
}

/* Palette legend under question navigator */
.palette-legend {
  display: flex; flex-wrap: wrap; gap: 4px 12px; justify-content: center;
  margin-top: 8px; font-size: 10.5px; color: var(--muted);
}
.palette-legend .lg {
  display: inline-block; width: 9px; height: 9px; border-radius: 2px;
  margin-right: 4px; vertical-align: -1px; border: 1px solid var(--line-strong);
}
.lg-cur { background: var(--card-subtle); border: 1.5px solid var(--leica-red); }
.lg-ans { background: var(--ink); border-color: var(--ink); }
.lg-flag { background: var(--warn-soft); border-color: var(--warn-border); }
.lg-ok { background: var(--ok); border-color: var(--ok); }
.lg-bad { background: var(--danger); border-color: var(--danger); }

@media (max-width: 960px) {
  .enter-grid { grid-template-columns: 1fr; }
}
@media (max-width: 560px) {
  .fgrid { grid-template-columns: 1fr; }
  .enter-sec { padding: 16px; }
}