/* ═══════════════════════════════════════════════════════════
   КВИЗ АРЕНА — ЕИТ МАТУРА
   CSS Architecture: Variables → Reset → Layout → Components → Animations
   ═══════════════════════════════════════════════════════════ */

/* ── 1. CSS CUSTOM PROPERTIES ─────────────────────────────── */
:root {
  /* Core palette: Deep Space */
  --bg:          #0b0d17;
  --bg-2:        #101322;
  --bg-3:        #161a2f;
  --bg-4:        #1c223c;
  --surface:     rgba(22, 26, 47, 0.4);
  --surface-2:   rgba(28, 34, 60, 0.6);
  --surface-blur: 12px;

  /* Neon Cyan accent */
  --accent:       #00f0ff;
  --accent-rgb:   0, 240, 255;
  --accent-light: #5cffff;
  --accent-dim:   rgba(0, 240, 255, 0.15);
  --accent-glow:  rgba(0, 240, 255, 0.4);
  --accent-border: rgba(0, 240, 255, 0.6);

  /* Purple secondary accent */
  --purple:       #8a2be2;
  --purple-glow:  rgba(138, 43, 226, 0.4);

  /* State colours */
  --correct:     #00ff9d;
  --correct-dim: rgba(0, 255, 157, 0.15);
  --wrong:       #ff0055;
  --wrong-dim:   rgba(255, 0, 85, 0.15);
  --warn:        #ffb700;
  --warn-dim:    rgba(255, 183, 0, 0.15);

  /* Text */
  --text:        #ffffff;
  --text-2:      #a0aabf;
  --text-3:      #6e7793;
  --text-inv:    #0b0d17;

  /* Border */
  --border:      rgba(255,255,255,0.08);
  --border-2:    rgba(255,255,255,0.15);

  /* Typography */
  --font-head:   'Outfit', sans-serif;
  --font:        'Plus Jakarta Sans', sans-serif;
  --font-mono:   'JetBrains Mono', 'Courier New', monospace;
  --fs-xs:       0.7rem;
  --fs-sm:       0.8rem;
  --fs-base:     1rem;
  --fs-md:       1.125rem;
  --fs-lg:       1.25rem;
  --fs-xl:       1.5rem;
  --fs-2xl:      2rem;
  --fs-3xl:      2.75rem;
  --fs-4xl:      4rem;

  /* Spacing */
  --gap-xs:  0.25rem;
  --gap-sm:  0.5rem;
  --gap:     1rem;
  --gap-lg:  1.5rem;
  --gap-xl:  2rem;
  --gap-2xl: 3rem;

  /* Easing */
  --ease-snap:   cubic-bezier(0.16, 1, 0.3, 1);
  --ease-hard:   cubic-bezier(0.7, 0, 0.3, 1);
  --ease-spring: cubic-bezier(0.34, 1.56, 0.64, 1);
  --ease-float:  cubic-bezier(0.25, 0.8, 0.25, 1);

  /* Shadows — Glass & Glow */
  --shadow-accent: 0 4px 20px var(--accent-glow);
  --shadow-correct: 0 4px 20px rgba(0, 255, 157, 0.3);
  --shadow-wrong: 0 4px 20px rgba(255, 0, 85, 0.3);
  --shadow-glass: 0 8px 32px 0 rgba(0, 0, 0, 0.3);

  /* Radius */
  --r: 16px;
  --r-sm: 8px;
  --r-lg: 24px;

  /* Z-index layers */
  --z-bg: -10;
  --z-base: 1;
  --z-card: 10;
  --z-modal: 100;
  --z-toast: 200;
}

/* ── 2. RESET & BASE ──────────────────────────────────────── */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}

body {
  background-color: var(--bg);
  color: var(--text);
  font-family: var(--font);
  font-size: var(--fs-base);
  line-height: 1.6;
  min-height: 100dvh;
  overflow-x: hidden;
  position: relative;
}

button {
  font-family: var(--font);
  cursor: pointer;
  border: none;
  background: none;
  color: inherit;
}

svg {
  display: inline-block;
  vertical-align: middle;
  flex-shrink: 0;
}

::selection {
  background: var(--accent);
  color: #fff;
}

/* ── 3. CANVAS BACKGROUND ────────────────────────────────── */
#bg-canvas {
  position: fixed;
  inset: 0;
  z-index: var(--z-bg);
  pointer-events: none;
  opacity: 0.4;
}

/* ── 4. NOISE + GRID OVERLAYS ────────────────────────────── */
.noise-overlay {
  position: fixed;
  inset: 0;
  z-index: calc(var(--z-bg) + 1);
  pointer-events: none;
  opacity: 0.025;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='noise'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23noise)'/%3E%3C/svg%3E");
  background-repeat: repeat;
  background-size: 128px 128px;
}

.grid-overlay {
  position: fixed;
  inset: 0;
  z-index: calc(var(--z-bg) + 2);
  pointer-events: none;
  background-image:
    repeating-linear-gradient(
      0deg,
      transparent,
      transparent 39px,
      rgba(255,255,255,0.025) 39px,
      rgba(255,255,255,0.025) 40px
    ),
    repeating-linear-gradient(
      90deg,
      transparent,
      transparent 39px,
      rgba(255,255,255,0.025) 39px,
      rgba(255,255,255,0.025) 40px
    );
}

/* ── 5. APP CONTAINER + SCREENS ──────────────────────────── */
#app {
  position: relative;
  z-index: var(--z-base);
  min-height: 100dvh;
}

.screen {
  display: none;
  min-height: 100dvh;
  padding: var(--gap-lg) var(--gap-xl) 140px var(--gap-xl);
  max-width: 1200px;
  margin: 0 auto;
  animation: screen-in 0.6s var(--ease-float) both;
}

.screen.active,
.screen:not([hidden]) {
  display: flex;
  flex-direction: column;
}

@keyframes screen-in {
  from { opacity: 0; transform: translateY(30px) scale(0.98); filter: blur(10px); }
  to   { opacity: 1; transform: translateY(0) scale(1); filter: blur(0); }
}

/* ── 6. LANDING SCREEN ────────────────────────────────────── */
.landing-header {
  display: grid;
  grid-template-columns: auto 1fr auto;
  align-items: start;
  gap: var(--gap-xl);
  padding-bottom: var(--gap-xl);
  border-bottom: 1px solid var(--border);
  margin-bottom: var(--gap-xl);
}

.logo-badge {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 2px;
}

.logo-tag {
  font-size: var(--fs-xs);
  font-weight: 800;
  letter-spacing: 0.25em;
  color: var(--accent);
  background: var(--accent-dim);
  border: 1px solid var(--accent-border);
  padding: 3px 8px;
  text-transform: uppercase;
}

.logo-version {
  font-size: var(--fs-xs);
  color: var(--text-3);
  letter-spacing: 0.1em;
  padding-left: 2px;
}

.header-title-wrap {
  text-align: center;
}

.main-title {
  font-family: var(--font-head);
  font-size: clamp(2.5rem, 5vw, var(--fs-4xl));
  font-weight: 800;
  letter-spacing: -0.02em;
  line-height: 1;
  color: var(--text);
  cursor: default;
  position: relative;
  display: inline-block;
}

.main-title::after {
  content: '';
  display: block;
  height: 3px;
  background: var(--accent);
  margin-top: 6px;
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.4s var(--ease-snap);
}

.main-title:hover::after {
  transform: scaleX(1);
}

/* Scramble state */
.main-title.scrambling {
  color: var(--accent-light);
}

.main-subtitle {
  font-size: var(--fs-sm);
  color: var(--text-3);
  letter-spacing: 0.08em;
  margin-top: 4px;
  text-transform: uppercase;
}

.header-stats {
  display: flex;
  flex-direction: column;
  gap: var(--gap-sm);
  align-items: flex-end;
}

.stat-pill {
  display: flex;
  align-items: baseline;
  gap: 6px;
  background: var(--surface);
  border: 1px solid var(--border);
  padding: 4px 10px;
}

.stat-num {
  font-size: var(--fs-lg);
  font-weight: 700;
  color: var(--accent-light);
}

.stat-lbl {
  font-size: var(--fs-xs);
  color: var(--text-3);
  letter-spacing: 0.1em;
}

/* Selection label divider */
.selection-label {
  display: flex;
  align-items: center;
  gap: var(--gap);
  margin-bottom: var(--gap-xl);
  color: var(--text-3);
  font-size: var(--fs-xs);
  letter-spacing: 0.2em;
}

.label-line {
  flex: 1;
  height: 1px;
  background: var(--border);
}

.label-text {
  white-space: nowrap;
  color: var(--accent);
}

/* ── 7. CATEGORY CARDS GRID ──────────────────────────────── */
.categories-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: var(--gap-lg);
  flex: 1;
  margin-bottom: var(--gap-xl);
}

.cat-card {
  position: relative;
  background: linear-gradient(145deg, rgba(22, 26, 47, 0.4) 0%, rgba(11, 13, 23, 0.6) 100%);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border: 1px solid var(--border);
  border-radius: var(--r-lg);
  padding: 1.5rem;
  cursor: pointer;
  transition: all 0.4s cubic-bezier(0.25, 0.8, 0.25, 1);
  will-change: transform, box-shadow, border-color;
  user-select: none;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  min-height: 190px;
}

.cat-card-content {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  position: relative;
  z-index: 2;
  height: 100%;
}

.cat-card-glow {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: radial-gradient(circle at 50% 0%, var(--glow-color) 0%, transparent 70%);
  opacity: 0;
  transition: opacity 0.4s ease;
  z-index: 0;
  pointer-events: none;
}

.cat-card-border {
  position: absolute;
  inset: 0;
  border-radius: inherit;
  padding: 2px;
  background: linear-gradient(180deg, var(--border-color), transparent);
  -webkit-mask: linear-gradient(#fff 0 0) content-box, linear-gradient(#fff 0 0);
  -webkit-mask-composite: xor;
  mask-composite: exclude;
  opacity: 0;
  transition: opacity 0.4s ease;
  pointer-events: none;
}

.cat-card:hover .cat-card-glow {
  opacity: 0.15;
}

.cat-card:hover .cat-card-border {
  opacity: 0.5;
}

.cat-card:hover {
  transform: translateY(-8px) scale(1.03);
  box-shadow: 0 12px 32px rgba(0,0,0,0.4), 0 4px 12px rgba(0,0,0,0.2);
  border-color: transparent;
}

.cat-card.selected .cat-card-glow {
  opacity: 0.25;
}

.cat-card.selected .cat-card-border {
  opacity: 1;
}

.cat-card.selected {
  transform: translateY(-8px) scale(1.03);
  box-shadow: 0 12px 32px rgba(0,0,0,0.5), 0 0 20px color-mix(in srgb, var(--glow-color) 30%, transparent);
  border-color: transparent;
  background: linear-gradient(145deg, rgba(22, 26, 47, 0.7) 0%, rgba(11, 13, 23, 0.8) 100%);
}

.cat-icon-wrap {
  width: 52px;
  height: 52px;
  border-radius: 14px;
  border: 1px solid;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);
  box-shadow: inset 0 2px 10px rgba(255,255,255,0.05);
}

.cat-icon-wrap svg {
  width: 24px;
  height: 24px;
}

.cat-card:hover .cat-icon-wrap,
.cat-card.selected .cat-icon-wrap {
  transform: scale(1.1) rotate(-5deg);
}

.cat-name {
  font-size: var(--fs-lg);
  font-weight: 800;
  line-height: 1.2;
  color: var(--text);
  margin-top: 0.5rem;
  transition: color 0.3s;
}

.cat-card.selected .cat-name {
  text-shadow: 0 0 15px color-mix(in srgb, var(--glow-color) 40%, transparent);
}

.cat-desc {
  font-size: 0.85rem;
  color: var(--text-3);
  line-height: 1.4;
  margin-top: -4px;
}

.cat-count {
  font-size: var(--fs-xs);
  color: var(--text-3);
  letter-spacing: 0.15em;
  text-transform: uppercase;
  margin-top: auto;
  display: flex;
  align-items: center;
  gap: 6px;
  padding-top: 1rem;
  border-top: 1px solid rgba(255,255,255,0.05);
}

.cat-count strong {
  color: var(--text);
  font-size: var(--fs-sm);
}

/* Selection indicator checkmark */
.cat-card::after {
  content: '';
  position: absolute;
  top: 1.5rem;
  right: 1.5rem;
  width: 22px;
  height: 22px;
  border-radius: 50%;
  border: 2px solid var(--border-2);
  background: rgba(0,0,0,0.2);
  transition: all 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);
  z-index: 5;
}

.cat-card.selected::after {
  background: var(--glow-color);
  border-color: var(--glow-color);
  box-shadow: 0 0 16px var(--glow-color);
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%23000' stroke-width='3.5' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='20 6 9 17 4 12'%3E%3C/polyline%3E%3C/svg%3E");
  background-size: 14px;
  background-position: center;
  background-repeat: no-repeat;
  transform: scale(1.15);
}

/* ── 8. START BAR ─────────────────────────────────────────── */
.start-bar {
  position: fixed;
  bottom: 0;
  left: 0;
  width: 100%;
  background: linear-gradient(0deg, rgba(11, 13, 23, 0.95) 0%, rgba(22, 26, 47, 0.8) 100%);
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  padding: 1.5rem 0;
  backdrop-filter: blur(24px);
  -webkit-backdrop-filter: blur(24px);
  z-index: var(--z-modal);
  box-shadow: 0 -10px 40px rgba(0,0,0,0.5);
  animation: start-bar-up 0.8s cubic-bezier(0.34, 1.56, 0.64, 1) both 0.4s;
}

@keyframes start-bar-up {
  from { transform: translateY(100%); opacity: 0; }
  to { transform: translateY(0); opacity: 1; }
}

.start-bar-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--gap-xl);
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--gap);
}

.start-info {
  display: flex;
  flex-direction: column;
  gap: 4px;
  font-size: var(--fs-base);
  color: var(--text-2);
}

#selected-count-label {
  font-weight: 500;
  letter-spacing: 0.05em;
}

#selected-count-label strong {
  color: var(--accent);
  font-size: var(--fs-lg);
  font-weight: 800;
  text-shadow: 0 0 10px var(--accent-glow);
}

#selected-q-count {
  font-size: var(--fs-sm);
  color: var(--text-3);
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

/* ── 9. BUTTONS ───────────────────────────────────────────── */
.btn-start {
  display: inline-flex;
  align-items: center;
  gap: var(--gap);
  background: linear-gradient(135deg, var(--accent) 0%, var(--purple) 100%);
  color: #fff;
  font-family: var(--font);
  font-size: var(--fs-lg);
  font-weight: 800;
  letter-spacing: 0.05em;
  padding: 1rem 2.5rem;
  border: none;
  border-radius: var(--r-lg);
  cursor: pointer;
  transition: all 0.4s cubic-bezier(0.25, 0.8, 0.25, 1);
  position: relative;
  overflow: hidden;
  z-index: 1;
  box-shadow: 0 8px 32px rgba(138, 43, 226, 0.4);
}

.btn-start::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, var(--purple) 0%, var(--accent) 100%);
  opacity: 0;
  transition: opacity 0.4s ease;
  z-index: -1;
}

.btn-start:hover::before {
  opacity: 1;
}

.btn-start:hover:not(:disabled) {
  box-shadow: 0 12px 40px var(--purple-glow), 0 0 20px var(--accent-glow);
  transform: translateY(-4px) scale(1.02);
}

.btn-start:active:not(:disabled) {
  transform: translateY(2px) scale(0.98);
  box-shadow: 0 4px 15px var(--purple-glow);
}

.btn-start:disabled,
.btn-start[aria-disabled="true"] {
  opacity: 0.5;
  filter: grayscale(0.8);
  cursor: not-allowed;
  pointer-events: none;
  box-shadow: none;
}

.btn-start .btn-icon {
  width: 24px;
  height: 24px;
  transition: transform 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.btn-start:hover .btn-icon {
  transform: translateX(8px) scale(1.1);
}

.btn-start .btn-icon {
  width: 18px;
  height: 18px;
  transition: transform 0.3s var(--ease-float);
}

.btn-start:hover .btn-icon {
  transform: translateX(6px);
}

.btn-ghost {
  display: inline-flex;
  align-items: center;
  gap: var(--gap-sm);
  background: transparent;
  color: var(--text-2);
  font-family: var(--font);
  font-size: var(--fs-sm);
  font-weight: 500;
  letter-spacing: 0.06em;
  padding: 0.6rem 1rem;
  border: 1px solid var(--border);
  border-radius: var(--r-sm);
  cursor: pointer;
  transition: all 0.2s var(--ease-float);
}

.btn-ghost:hover {
  border-color: var(--border-2);
  color: var(--text);
  background: var(--surface);
  transform: translateY(-2px);
}

.btn-ghost svg {
  width: 16px;
  height: 16px;
}

.btn-secondary {
  display: inline-flex;
  align-items: center;
  gap: var(--gap-sm);
  background: var(--surface);
  backdrop-filter: blur(var(--surface-blur));
  color: var(--text);
  font-family: var(--font);
  font-size: var(--fs-base);
  font-weight: 600;
  letter-spacing: 0.06em;
  padding: 0.75rem 1.5rem;
  border: 1px solid var(--border-2);
  border-radius: var(--r-sm);
  cursor: pointer;
  transition: all 0.3s var(--ease-float);
}

.btn-secondary:hover {
  border-color: var(--accent-border);
  box-shadow: var(--shadow-accent);
  transform: translateY(-2px);
}

.btn-secondary svg {
  width: 16px;
  height: 16px;
}

.btn-danger {
  display: inline-flex;
  align-items: center;
  gap: var(--gap-sm);
  background: var(--wrong);
  color: #fff;
  font-family: var(--font);
  font-size: var(--fs-base);
  font-weight: 700;
  padding: 0.6rem 1.25rem;
  border: 2px solid var(--wrong);
  border-radius: var(--r-sm);
  cursor: pointer;
  transition: all 0.2s var(--ease-float);
}

.btn-danger:hover {
  box-shadow: 0 4px 16px rgba(255, 0, 85, 0.4);
  transform: translateY(-2px);
}

/* ── 10. QUIZ SCREEN ──────────────────────────────────────── */
.quiz-topbar {
  display: grid;
  grid-template-columns: 1fr auto auto;
  align-items: center;
  gap: var(--gap-lg);
  padding-bottom: var(--gap-lg);
  border-bottom: 1px solid var(--border);
  margin-bottom: var(--gap-lg);
}

.quiz-meta {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.quiz-category-tag {
  font-size: var(--fs-xs);
  letter-spacing: 0.15em;
  color: var(--accent);
  text-transform: uppercase;
}

.quiz-progress-text {
  font-size: var(--fs-sm);
  color: var(--text-3);
}

/* Timer */
.timer-ring-wrap {
  position: relative;
  width: 44px;
  height: 44px;
}

.timer-ring {
  width: 44px;
  height: 44px;
  overflow: visible;
}

.timer-ring-bg {
  stroke: var(--surface-2);
}

.timer-ring-bar {
  stroke: var(--accent);
  transition: stroke-dashoffset 1s linear, stroke 0.3s;
}

.timer-ring-bar.warn {
  stroke: var(--warn);
}

.timer-ring-bar.urgent {
  stroke: var(--wrong);
  animation: pulse-urgent 0.5s ease infinite alternate;
}

@keyframes pulse-urgent {
  from { opacity: 1; }
  to   { opacity: 0.4; }
}

.timer-value {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--fs-xs);
  font-weight: 700;
  color: var(--text);
}

/* ── 11. NEURAL MAP ───────────────────────────────────────── */
.neural-map-wrap {
  margin-bottom: var(--gap-lg);
  overflow-x: auto;
  scrollbar-width: none;
  padding: var(--gap) 0;
}

.neural-map-wrap::-webkit-scrollbar {
  display: none;
}

.neural-map {
  height: 60px;
  min-width: 100%;
  overflow: visible;
}

.nm-line {
  stroke: var(--border-2);
  stroke-width: 2;
  transition: stroke 0.4s var(--ease-float);
}

.nm-line.active {
  stroke: var(--accent);
  stroke-dasharray: 8 6;
  filter: drop-shadow(0 0 6px var(--accent-glow));
  animation: nm-dash 1s linear infinite;
}

@keyframes nm-dash {
  to { stroke-dashoffset: -14; }
}

.nm-node {
  fill: var(--surface-2);
  stroke: var(--border-2);
  stroke-width: 1.5;
  cursor: default;
  transition: fill 0.2s var(--ease-snap), stroke 0.2s;
}

.nm-node.current {
  fill: var(--accent-dim);
  stroke: var(--accent);
  animation: node-pulse 1.2s ease infinite alternate;
}

@keyframes node-pulse {
  from { filter: drop-shadow(0 0 3px var(--accent-glow)); }
  to   { filter: drop-shadow(0 0 8px var(--accent-glow)); }
}

.nm-node.correct {
  fill: var(--correct-dim);
  stroke: var(--correct);
  filter: drop-shadow(0 0 4px rgba(34,197,94,0.4));
}

.nm-node.wrong {
  fill: var(--wrong-dim);
  stroke: var(--wrong);
}

.nm-node.timeout {
  fill: var(--warn-dim);
  stroke: var(--warn);
}

.nm-label {
  font-family: var(--font);
  font-size: 9px;
  fill: var(--text-3);
  text-anchor: middle;
  dominant-baseline: middle;
  pointer-events: none;
}

.nm-label.current-lbl {
  fill: var(--accent-light);
}

/* ── 12. QUESTION CARD ────────────────────────────────────── */
.question-card {
  background: linear-gradient(145deg, rgba(22, 26, 47, 0.5) 0%, rgba(11, 13, 23, 0.7) 100%);
  backdrop-filter: blur(24px);
  -webkit-backdrop-filter: blur(24px);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: var(--r-lg);
  padding: var(--gap-2xl);
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: var(--gap-lg);
  box-shadow: 0 16px 40px rgba(0,0,0,0.4);
  position: relative;
  overflow: hidden;
}

.question-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; width: 100%; height: 4px;
  background: var(--current-cat-color, var(--accent));
  box-shadow: 0 0 15px var(--current-cat-color, var(--accent));
}

.card-enter {
  animation: card-reveal 0.6s cubic-bezier(0.2, 0.8, 0.2, 1) both;
}

@keyframes card-reveal {
  0% { opacity: 0; transform: perspective(1200px) rotateX(15deg) translateY(40px) scale(0.95); filter: blur(12px); }
  100% { opacity: 1; transform: perspective(1200px) rotateX(0deg) translateY(0) scale(1); filter: blur(0); }
}

.question-number-tag {
  font-size: var(--fs-xs);
  letter-spacing: 0.2em;
  color: var(--accent);
  font-weight: 700;
  border-left: 3px solid var(--accent);
  padding-left: var(--gap-sm);
}

.question-text {
  font-size: clamp(1rem, 2.5vw, var(--fs-xl));
  font-weight: 500;
  line-height: 1.5;
  color: var(--text);
  letter-spacing: -0.01em;
}

/* Code block */
.code-block-wrap {
  background: var(--bg);
  border: 1px solid var(--border);
  border-left: 3px solid var(--accent);
  overflow: hidden;
}

.code-block-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 6px 12px;
  background: var(--bg-3);
  border-bottom: 1px solid var(--border);
}

.code-lang {
  font-size: var(--fs-xs);
  color: var(--accent);
  letter-spacing: 0.1em;
  font-weight: 700;
}

.code-copy-hint {
  font-size: var(--fs-xs);
  color: var(--text-3);
}

.code-pre {
  margin: 0;
  padding: var(--gap);
  overflow-x: auto;
  scrollbar-width: thin;
  scrollbar-color: var(--border) transparent;
}

.code-content {
  font-family: var(--font);
  font-size: var(--fs-sm);
  line-height: 1.7;
  white-space: pre;
  color: var(--text);
}

/* Syntax highlighting classes (set by JS) */
.tok-kw    { color: #818cf8; font-weight: 700; }  /* keyword */
.tok-str   { color: #86efac; }                      /* string */
.tok-num   { color: #fbbf24; }                      /* number */
.tok-cmt   { color: var(--text-3); font-style: italic; } /* comment */
.tok-fn    { color: #67e8f9; }                      /* function */
.tok-cls   { color: #fb923c; }                      /* class */
.tok-op    { color: #c084fc; }                      /* operator */
.tok-punct { color: var(--text-2); }               /* punctuation */

/* ── 13. OPTIONS ──────────────────────────────────────────── */
.options-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--gap);
}

@media (max-width: 600px) {
  .options-grid { grid-template-columns: 1fr; }
}

.option-btn {
  display: flex;
  align-items: center;
  gap: var(--gap);
  background: linear-gradient(90deg, rgba(28, 34, 60, 0.3) 0%, rgba(22, 26, 47, 0.5) 100%);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid rgba(255, 255, 255, 0.05);
  border-radius: var(--r);
  padding: 1rem 1.25rem;
  cursor: pointer;
  text-align: left;
  font-family: var(--font);
  font-size: var(--fs-md);
  color: var(--text);
  line-height: 1.5;
  transition: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
  position: relative;
  overflow: hidden;
  box-shadow: 0 4px 15px rgba(0,0,0,0.1);
}

.option-btn::after {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: inherit;
  padding: 2px;
  background: linear-gradient(135deg, var(--accent), transparent);
  -webkit-mask: linear-gradient(#fff 0 0) content-box, linear-gradient(#fff 0 0);
  -webkit-mask-composite: xor;
  mask-composite: exclude;
  opacity: 0;
  transition: opacity 0.3s ease;
  pointer-events: none;
}

.option-btn:hover::after,
.option-btn.selected::after {
  opacity: 1;
}

.option-btn:hover {
  background: linear-gradient(90deg, rgba(28, 34, 60, 0.5) 0%, rgba(22, 26, 47, 0.7) 100%);
  transform: translateY(-3px) scale(1.01);
  box-shadow: 0 8px 25px rgba(0,0,0,0.25);
}

.option-btn:active {
  transform: translateY(1px) scale(0.99);
}

.option-btn.selected {
  background: color-mix(in srgb, var(--surface) 20%, var(--accent) 25%);
  transform: translateY(-3px) scale(1.01);
}

.option-btn.correct {
  background: var(--correct-dim) !important;
  box-shadow: 0 0 25px rgba(0, 255, 157, 0.2) !important;
  border-color: transparent !important;
}
.option-btn.correct::after {
  background: linear-gradient(135deg, var(--correct), transparent);
  opacity: 1;
}

.option-btn.wrong {
  background: var(--wrong-dim) !important;
  box-shadow: 0 0 25px rgba(255, 0, 85, 0.2) !important;
  border-color: transparent !important;
}
.option-btn.wrong::after {
  background: linear-gradient(135deg, var(--wrong), transparent);
  opacity: 1;
}

.option-btn.disabled {
  pointer-events: none;
  opacity: 0.6;
}

.option-btn.disabled.selected,
.option-btn.disabled.correct,
.option-btn.disabled.wrong {
  opacity: 1;
}

.opt-letter {
  flex-shrink: 0;
  width: 28px;
  height: 28px;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 1px solid rgba(255, 255, 255, 0.15);
  border-radius: 8px;
  font-size: var(--fs-xs);
  font-weight: 800;
  color: var(--text-2);
  transition: all 0.3s cubic-bezier(0.34, 1.56, 0.64, 1);
  background: rgba(0,0,0,0.2);
  position: relative;
  z-index: 1;
}

.option-btn:hover .opt-letter {
  border-color: var(--accent);
  color: var(--accent-light);
  background: var(--accent-dim);
  transform: scale(1.1);
}

.option-btn.selected .opt-letter {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
  transform: scale(1.1);
}

.option-btn.correct .opt-letter {
  background: var(--correct);
  border-color: var(--correct);
  color: #000;
  transform: scale(1.1);
}

.option-btn.wrong .opt-letter {
  background: var(--wrong);
  border-color: var(--wrong);
  color: #fff;
  transform: scale(1.1);
}

.opt-text {
  flex: 1;
  position: relative;
  z-index: 1;
}

.opt-indicator {
  flex-shrink: 0;
  width: 24px;
  height: 24px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  opacity: 0;
  transform: scale(0.5);
  transition: all 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.opt-indicator svg {
  width: 16px;
  height: 16px;
}

.option-btn.correct .opt-indicator {
  background: var(--correct);
  color: #000;
  opacity: 1;
  transform: scale(1);
}

.option-btn.wrong .opt-indicator {
  background: var(--wrong);
  color: #fff;
  opacity: 1;
  transform: scale(1);
}
.option-btn.wrong .opt-indicator svg {
  stroke: #fff;
}

/* ── 14. FEEDBACK MODAL ───────────────────────────────────── */
.feedback-modal {
  border: none;
  background: transparent;
  padding: 0;
  max-width: 600px;
  width: calc(100% - 2rem);
  margin: auto; /* Default centering */
}

.feedback-modal::backdrop {
  background: rgba(5, 5, 5, 0.85);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  animation: backdrop-in 0.4s ease both;
}

@keyframes backdrop-in {
  from { opacity: 0; }
  to   { opacity: 1; }
}

.modal-inner {
  background: linear-gradient(145deg, rgba(22, 26, 47, 0.85) 0%, rgba(11, 13, 23, 0.95) 100%);
  backdrop-filter: blur(32px);
  -webkit-backdrop-filter: blur(32px);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: 24px;
  padding: 3.5rem 2.5rem 2.5rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: var(--gap-lg);
  animation: modal-super-pop 0.6s cubic-bezier(0.34, 1.56, 0.64, 1) both;
  box-shadow: 0 32px 80px rgba(0,0,0,0.7);
  position: relative;
  overflow: visible;
}

@keyframes modal-super-pop {
  0% { opacity: 0; transform: perspective(1200px) rotateX(-20deg) translateY(80px) scale(0.8); filter: blur(20px); }
  100% { opacity: 1; transform: perspective(1200px) rotateX(0deg) translateY(0) scale(1); filter: blur(0); }
}

.modal-inner.correct-modal {
  border-color: rgba(0, 255, 157, 0.3);
  box-shadow: 0 20px 60px rgba(0, 255, 157, 0.15), inset 0 0 60px rgba(0, 255, 157, 0.05);
}

.modal-inner.wrong-modal {
  border-color: rgba(255, 0, 85, 0.3);
  box-shadow: 0 20px 60px rgba(255, 0, 85, 0.15), inset 0 0 60px rgba(255, 0, 85, 0.05);
}

.modal-icon-wrap {
  width: 80px;
  height: 80px;
  border-radius: 50%;
  border: 4px solid var(--surface);
  display: flex;
  align-items: center;
  justify-content: center;
  position: absolute;
  top: -40px;
  left: 50%;
  margin-left: -40px;
  box-shadow: 0 10px 30px rgba(0,0,0,0.5);
  z-index: 10;
}

.modal-inner.correct-modal .modal-icon-wrap {
  background: var(--correct);
  border-color: #0b0d17;
  animation: icon-pop-correct 0.6s cubic-bezier(0.34, 1.56, 0.64, 1) both 0.2s;
}

.modal-inner.wrong-modal .modal-icon-wrap {
  background: var(--wrong);
  border-color: #0b0d17;
  animation: icon-pop-wrong 0.6s cubic-bezier(0.34, 1.56, 0.64, 1) both 0.2s;
}

@keyframes icon-pop-correct {
  0%   { transform: scale(0) rotate(-45deg); }
  60%  { transform: scale(1.2) rotate(10deg); }
  100% { transform: scale(1) rotate(0); }
}

@keyframes icon-pop-wrong {
  0%   { transform: scale(0); }
  40%  { transform: scale(1.1) translateX(-10px); }
  60%  { transform: scale(1.1) translateX(10px); }
  80%  { transform: scale(1.1) translateX(-5px); }
  100% { transform: scale(1) translateX(0); }
}

.modal-icon {
  width: 40px;
  height: 40px;
  color: #fff;
  stroke-width: 3;
}

.modal-inner.correct-modal .modal-icon {
  color: #000;
}

.modal-content {
  width: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--gap-lg);
}

.modal-content > * {
  animation: slide-up-fade 0.5s cubic-bezier(0.2, 0.8, 0.2, 1) both;
}
.modal-content > *:nth-child(1) { animation-delay: 0.1s; }
.modal-content > *:nth-child(2) { animation-delay: 0.2s; }
.modal-content > *:nth-child(3) { animation-delay: 0.3s; }
.modal-content > *:nth-child(4) { animation-delay: 0.4s; }

@keyframes slide-up-fade {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}

.modal-title {
  font-size: var(--fs-2xl);
  font-weight: 800;
  letter-spacing: -0.02em;
  margin-top: 0.5rem;
}

.modal-inner.correct-modal .modal-title {
  background: linear-gradient(90deg, #fff, var(--correct));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  text-shadow: 0 0 30px rgba(0, 255, 157, 0.3);
}

.modal-inner.wrong-modal .modal-title {
  background: linear-gradient(90deg, #fff, var(--wrong));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  text-shadow: 0 0 30px rgba(255, 0, 85, 0.3);
}

.modal-body {
  font-size: var(--fs-md);
  color: var(--text-2);
  line-height: 1.6;
}

.modal-correct-answer,
.modal-concept {
  width: 100%;
  background: rgba(0,0,0,0.3);
  border: 1px solid rgba(255,255,255,0.08);
  border-radius: var(--r);
  padding: 1.25rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 6px;
  position: relative;
  overflow: hidden;
}

.modal-correct-answer::before {
  content: ''; position: absolute; top:0; left:0; width: 100%; height: 3px; background: var(--correct);
  box-shadow: 0 0 15px var(--correct);
}

.modal-concept::before {
  content: ''; position: absolute; top:0; left:0; width: 100%; height: 3px; background: var(--accent);
  box-shadow: 0 0 15px var(--accent);
}

.mca-label, .mc-label {
  font-size: var(--fs-xs);
  color: var(--text-3);
  letter-spacing: 0.15em;
  text-transform: uppercase;
}

.mca-value {
  font-size: var(--fs-lg);
  font-weight: 800;
  color: var(--correct);
}

.mc-value {
  font-size: var(--fs-base);
  color: var(--accent-light);
}

.btn-modal-next {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  gap: var(--gap);
  background: linear-gradient(135deg, var(--accent) 0%, var(--purple) 100%);
  color: #fff;
  font-family: var(--font);
  font-size: var(--fs-lg);
  font-weight: 800;
  letter-spacing: 0.05em;
  padding: 1.25rem 2rem;
  border: none;
  border-radius: var(--r-lg);
  cursor: pointer;
  transition: all 0.4s cubic-bezier(0.25, 0.8, 0.25, 1);
  box-shadow: 0 10px 30px rgba(138, 43, 226, 0.3);
  margin-top: var(--gap-lg);
  animation: slide-up-fade 0.5s cubic-bezier(0.2, 0.8, 0.2, 1) both 0.5s;
}

.btn-modal-next:hover {
  transform: translateY(-4px) scale(1.02);
  box-shadow: 0 15px 40px var(--purple-glow), 0 0 20px var(--accent-glow);
}

.btn-modal-next:active {
  transform: translateY(2px) scale(0.98);
}

.btn-modal-next svg {
  width: 24px;
  height: 24px;
  transition: transform 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.btn-modal-next:hover svg {
  transform: translateX(8px) scale(1.1);
}

.btn-modal-next svg {
  width: 18px;
  height: 18px;
}

.btn-abort {
  font-size: var(--fs-xs);
  letter-spacing: 0.1em;
}

/* ── 15. CONFIRM MODAL ────────────────────────────────────── */
.confirm-modal {
  border: none;
  background: transparent;
  padding: 0;
  max-width: 380px;
  width: calc(100% - 2rem);
}

.confirm-modal::backdrop {
  background: rgba(5,5,5,0.8);
  backdrop-filter: blur(4px);
}

.confirm-inner {
  background: var(--surface);
  border: 1px solid var(--wrong);
  box-shadow: var(--shadow-wrong);
  padding: var(--gap-xl);
  display: flex;
  flex-direction: column;
  gap: var(--gap-lg);
}

.confirm-inner h3 {
  font-size: var(--fs-lg);
  color: var(--wrong);
}

.confirm-inner p {
  font-size: var(--fs-sm);
  color: var(--text-2);
}

.confirm-actions {
  display: flex;
  gap: var(--gap);
  justify-content: flex-end;
}

/* ── 16. RESULTS SCREEN ───────────────────────────────────── */
/* ── 16. RESULTS SCREEN ───────────────────────────────────── */
.results-header {
  padding-bottom: var(--gap-xl);
  border-bottom: 1px solid rgba(255,255,255,0.1);
  margin-bottom: var(--gap-xl);
  animation: fade-in 0.6s ease both;
}

@keyframes fade-in {
  from { opacity: 0; }
  to   { opacity: 1; }
}

.results-title-row {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: var(--gap-xl);
}

.results-title {
  font-size: clamp(2rem, 4vw, var(--fs-3xl));
  font-weight: 800;
  letter-spacing: -0.02em;
  background: linear-gradient(90deg, #fff, var(--text-2));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.results-grade {
  font-size: var(--fs-2xl);
  font-weight: 800;
  letter-spacing: -0.02em;
  border: 2px solid transparent;
  padding: 8px 24px;
  border-radius: var(--r-sm);
  min-width: 80px;
  text-align: center;
  transition: all 0.3s var(--ease-snap);
  background: rgba(0,0,0,0.2);
  backdrop-filter: blur(8px);
}

.results-grade.grade-a, .results-grade.grade-5plus, .results-grade.grade-5 {
  color: var(--correct);
  border-color: var(--correct);
  box-shadow: 0 0 20px rgba(0, 255, 157, 0.2), inset 0 0 10px rgba(0, 255, 157, 0.1);
}

.results-grade.grade-b, .results-grade.grade-4 {
  color: var(--accent-light);
  border-color: var(--accent);
  box-shadow: 0 0 20px rgba(0, 240, 255, 0.2), inset 0 0 10px rgba(0, 240, 255, 0.1);
}

.results-grade.grade-c, .results-grade.grade-3 {
  color: var(--warn);
  border-color: var(--warn);
  box-shadow: 0 0 20px rgba(255, 183, 0, 0.2), inset 0 0 10px rgba(255, 183, 0, 0.1);
}

.results-grade.grade-d, .results-grade.grade-2, .results-grade.grade-1 {
  color: var(--wrong);
  border-color: var(--wrong);
  box-shadow: 0 0 20px rgba(255, 0, 85, 0.2), inset 0 0 10px rgba(255, 0, 85, 0.1);
}

.results-subtitle {
  margin-top: 6px;
  font-size: var(--fs-sm);
  color: var(--text-3);
  letter-spacing: 0.08em;
}

.results-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  grid-template-rows: auto auto;
  gap: var(--gap-lg);
  flex: 1;
  margin-bottom: var(--gap-xl);
}

@media (max-width: 768px) {
  .results-grid { grid-template-columns: 1fr; }
}

.res-card {
  background: linear-gradient(145deg, rgba(22, 26, 47, 0.4) 0%, rgba(11, 13, 23, 0.6) 100%);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border: 1px solid rgba(255,255,255,0.08);
  border-radius: var(--r-lg);
  padding: var(--gap-xl);
  display: flex;
  flex-direction: column;
  gap: var(--gap-lg);
  box-shadow: 0 16px 40px rgba(0,0,0,0.4);
  animation: card-reveal 0.6s cubic-bezier(0.2, 0.8, 0.2, 1) both;
}

.res-card:nth-child(1) { animation-delay: 0.1s; }
.res-card:nth-child(2) { animation-delay: 0.2s; }
.res-card:nth-child(3) { animation-delay: 0.3s; }
.res-card:nth-child(4) { animation-delay: 0.4s; }

.res-card-title {
  display: flex;
  align-items: center;
  gap: var(--gap-sm);
  font-size: var(--fs-sm);
  font-weight: 700;
  letter-spacing: 0.1em;
  color: var(--text-2);
  text-transform: uppercase;
  border-bottom: 1px solid rgba(255,255,255,0.08);
  padding-bottom: var(--gap);
}

.res-card-title svg {
  width: 16px;
  height: 16px;
  color: var(--accent);
}

/* Radial score */
.res-card-main {
  grid-row: span 1;
  flex-direction: row;
  align-items: center;
  gap: var(--gap-xl);
  flex-wrap: wrap;
}

.radial-score-wrap {
  position: relative;
  width: 160px;
  height: 160px;
  flex-shrink: 0;
  filter: drop-shadow(0 0 15px rgba(0,240,255,0.1));
}

.radial-score-svg {
  width: 160px;
  height: 160px;
  overflow: visible;
}

.rs-track {
  stroke: rgba(255,255,255,0.05);
}

.rs-fill {
  stroke: var(--accent);
  stroke-linecap: round;
  transition: stroke-dashoffset 1.5s cubic-bezier(0.34, 1.56, 0.64, 1), stroke 0.5s;
  filter: drop-shadow(0 0 8px var(--accent-glow));
}

.radial-score-text {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 2px;
}

.rs-pct {
  font-size: var(--fs-2xl);
  font-weight: 800;
  letter-spacing: -0.02em;
  color: var(--text);
  text-shadow: 0 0 10px rgba(255,255,255,0.3);
}

.rs-label {
  font-size: var(--fs-xs);
  color: var(--text-3);
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.main-score-details {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: var(--gap);
}

.score-detail-row {
  display: flex;
  align-items: center;
  gap: var(--gap-sm);
  font-size: var(--fs-sm);
  color: var(--text-2);
}

.score-detail-row strong {
  margin-left: auto;
  font-size: var(--fs-base);
  color: var(--text);
}

.sdr-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  flex-shrink: 0;
}

.sdr-correct { background: var(--correct); box-shadow: 0 0 8px var(--correct); }
.sdr-wrong   { background: var(--wrong); box-shadow: 0 0 8px var(--wrong); }
.sdr-time    { background: var(--accent); box-shadow: 0 0 8px var(--accent); }

/* Category bars */
.cat-bars-wrap {
  display: flex;
  flex-direction: column;
  gap: var(--gap);
  flex: 1;
}

.cat-bar-item {
  display: flex;
  flex-direction: column;
  gap: 6px;
  position: relative;
  animation: slide-right 0.6s var(--ease-spring) both;
}
.cat-bar-item:nth-child(2) { animation-delay: 0.1s; }
.cat-bar-item:nth-child(3) { animation-delay: 0.2s; }
.cat-bar-item:nth-child(4) { animation-delay: 0.3s; }

@keyframes slide-right {
  from { opacity: 0; transform: translateX(-15px); }
  to   { opacity: 1; transform: translateX(0); }
}

.cb-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: var(--fs-xs);
  color: var(--text-2);
}

.cb-score {
  font-weight: 700;
  color: var(--text);
}

.cb-track {
  height: 8px;
  background: rgba(0,0,0,0.3);
  border-radius: 4px;
  position: relative;
  overflow: hidden;
  box-shadow: inset 0 1px 3px rgba(0,0,0,0.5);
}

.cb-fill {
  position: absolute;
  inset: 0 auto 0 0;
  width: 0%;
  border-radius: 4px;
  transition: width 1s cubic-bezier(0.34, 1.56, 0.64, 1);
  box-shadow: 0 0 10px currentColor;
}

.cb-pct {
  position: absolute;
  right: 0;
  top: -20px;
  font-size: 10px;
  font-weight: 800;
  color: var(--text-3);
  opacity: 0; /* JS can fade this in, or just hide */
}

/* Review list */
.review-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: var(--gap-sm);
  flex: 1;
  overflow-y: auto;
  max-height: 280px;
  scrollbar-width: thin;
  scrollbar-color: var(--border) transparent;
}

.review-item {
  display: flex;
  align-items: flex-start;
  gap: var(--gap-sm);
  font-size: var(--fs-sm);
  color: var(--text-2);
  padding: var(--gap-sm) var(--gap);
  background: linear-gradient(90deg, rgba(255,0,85,0.05), transparent);
  border-left: 2px solid var(--wrong);
  border-radius: 0 4px 4px 0;
  animation: review-item-in 0.4s var(--ease-snap) both;
}
.review-item:nth-child(1) { animation-delay: 0.1s; }
.review-item:nth-child(2) { animation-delay: 0.2s; }
.review-item:nth-child(3) { animation-delay: 0.3s; }
.review-item:nth-child(4) { animation-delay: 0.4s; }

@keyframes review-item-in {
  from { opacity: 0; transform: translateX(-10px); }
  to   { opacity: 1; transform: translateX(0); }
}

.review-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--wrong);
  box-shadow: 0 0 6px var(--wrong);
  flex-shrink: 0;
  margin-top: 6px;
}

.no-review {
  font-size: var(--fs-base);
  color: var(--correct);
  padding: var(--gap);
  text-align: center;
  border: 1px dashed rgba(0,255,157,0.3);
  background: rgba(0,255,157,0.05);
  border-radius: var(--r-sm);
  animation: fade-in 0.6s ease both;
}

/* Timeline */
.timeline-wrap {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  align-content: flex-start;
}

.tl-dot {
  width: 24px;
  height: 24px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  font-size: 10px;
  font-weight: 700;
  cursor: default;
  transition: transform 0.2s cubic-bezier(0.34, 1.56, 0.64, 1);
  animation: tl-pop 0.4s cubic-bezier(0.34, 1.56, 0.64, 1) both;
}

@keyframes tl-pop {
  from { opacity: 0; transform: scale(0.5); }
  to   { opacity: 1; transform: scale(1); }
}

.tl-dot:hover {
  transform: scale(1.3);
  z-index: 10;
}

.tl-correct {
  background: rgba(0, 255, 157, 0.1);
  border: 1px solid var(--correct);
  color: var(--correct);
  box-shadow: 0 0 10px rgba(0, 255, 157, 0.2);
}

.tl-wrong {
  background: rgba(255, 0, 85, 0.1);
  border: 1px solid var(--wrong);
  color: var(--wrong);
  box-shadow: 0 0 10px rgba(255, 0, 85, 0.2);
}

/* Results actions */
.results-actions {
  display: flex;
  gap: var(--gap);
  justify-content: flex-end;
  padding-top: var(--gap-lg);
  border-top: 1px solid rgba(255,255,255,0.1);
  animation: fade-in 0.6s ease both 0.5s;
}

/* ── 17. SCROLLBAR ────────────────────────────────────────── */
::-webkit-scrollbar {
  width: 4px;
  height: 4px;
}

::-webkit-scrollbar-track {
  background: transparent;
}

::-webkit-scrollbar-thumb {
  background: var(--border-2);
}

::-webkit-scrollbar-thumb:hover {
  background: var(--accent-border);
}

/* ── 18. RESPONSIVE ───────────────────────────────────────── */
@media (max-width: 768px) {
  .screen {
    padding: var(--gap) var(--gap);
  }

  .landing-header {
    grid-template-columns: 1fr;
    text-align: center;
  }

  .header-stats {
    flex-direction: row;
    justify-content: center;
  }

  .start-bar {
    flex-direction: column;
    align-items: stretch;
    padding: var(--gap-lg) var(--gap);
    border-radius: var(--r-lg) var(--r-lg) 0 0;
    box-shadow: 0 -8px 32px rgba(0,0,0,0.4);
    background: var(--surface-2);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    margin: 0 calc(var(--gap) * -1);
  }

  .start-info {
    align-items: center;
    margin-bottom: var(--gap-sm);
  }

  .btn-start {
    justify-content: center;
    width: 100%;
  }

  .logo-badge {
    align-items: center;
  }

  .categories-grid {
    grid-template-columns: 1fr 1fr;
  }

  .quiz-topbar {
    grid-template-columns: 1fr auto;
  }

  .btn-abort span { display: none; }

  .results-title-row {
    flex-direction: column;
  }

  .res-card-main {
    flex-direction: column;
    align-items: flex-start;
  }
}

@media (max-width: 480px) {
  .categories-grid {
    grid-template-columns: 1fr;
  }

  .options-grid {
    grid-template-columns: 1fr;
  }
}

/* ── 19. FOCUS STYLES ─────────────────────────────────────── */
:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
}

/* ── 20. LOADING STATE ────────────────────────────────────── */
@keyframes shimmer {
  from { background-position: -400px 0; }
  to   { background-position: 400px 0; }
}

.shimmer {
  background: linear-gradient(
    90deg,
    var(--surface) 25%,
    var(--surface-2) 50%,
    var(--surface) 75%
  );
  background-size: 400px 100%;
  animation: shimmer 1.5s infinite linear;
}

/* ── 21. PROGRESS INDICATOR AT TOP ───────────────────────── */
.top-progress-bar {
  position: fixed;
  top: 0;
  left: 0;
  height: 2px;
  background: var(--accent);
  z-index: calc(var(--z-modal) + 1);
  transition: width 0.3s var(--ease-snap);
  box-shadow: 0 0 8px var(--accent-glow);
}