*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg1: #0d0f1e;
  --bg2: #151829;
  --glass: rgba(255,255,255,0.06);
  --glass-border: rgba(255,255,255,0.12);
  --glass-hover: rgba(255,255,255,0.10);
  --blur: blur(20px);
  --text: #f0f0ff;
  --muted: rgba(240,240,255,0.5);
  --faint: rgba(240,240,255,0.2);
  --accent-a: #a78bfa;   /* violet */
  --accent-b: #38bdf8;   /* sky */
  --accent-c: #fb7185;   /* rose */
  --accent-d: #34d399;   /* emerald */
  --accent-e: #fbbf24;   /* amber */
  --correct: #34d399;
  --wrong: #fb7185;
  --r: 18px;
}

body {
  min-height: 100vh;
  background: var(--bg1);
  font-family: 'Cabinet Grotesk', sans-serif;
  color: var(--text);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
  overflow-x: hidden;
  position: relative;
}

/* Animated mesh background */
.bg-mesh {
  position: fixed; inset: 0; z-index: 0; overflow: hidden;
}
.blob {
  position: absolute;
  border-radius: 50%;
  filter: blur(80px);
  opacity: 0.55;
  animation: float 12s ease-in-out infinite alternate;
}
.blob1 { width: 500px; height: 500px; background: #4f46e5; top: -15%; left: -10%; animation-delay: 0s; }
.blob2 { width: 400px; height: 400px; background: #0ea5e9; top: 40%; right: -10%; animation-delay: -4s; }
.blob3 { width: 350px; height: 350px; background: #db2777; bottom: -10%; left: 30%; animation-delay: -8s; }
.blob4 { width: 300px; height: 300px; background: #059669; top: 20%; left: 50%; animation-delay: -2s; }

@keyframes float {
  from { transform: translate(0,0) scale(1); }
  to { transform: translate(30px, 25px) scale(1.08); }
}

/* Grain overlay */
body::after {
  content: '';
  position: fixed; inset: 0; z-index: 1;
  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)' opacity='0.04'/%3E%3C/svg%3E");
  pointer-events: none;
  opacity: 0.4;
}

.app {
  width: 100%;
  max-width: 640px;
  position: relative;
  z-index: 2;
}

/* Screens */
.screen { display: none; }
.screen.active { display: block; animation: slideUp 0.45s cubic-bezier(0.22,1,0.36,1) both; }
@keyframes slideUp {
  from { opacity: 0; transform: translateY(28px) scale(0.98); }
  to { opacity: 1; transform: translateY(0) scale(1); }
}

/* Glass card */
.glass {
  background: var(--glass);
  border: 1px solid var(--glass-border);
  border-radius: var(--r);
  backdrop-filter: var(--blur);
  -webkit-backdrop-filter: var(--blur);
}

/* ─────────────────────────────────────────────
   HOME SCREEN
───────────────────────────────────────────── */
.home-logo {
  text-align: center;
  margin-bottom: 36px;
}
.logo-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: rgba(167,139,250,0.15);
  border: 1px solid rgba(167,139,250,0.3);
  border-radius: 100px;
  padding: 6px 18px;
  font-family: 'JetBrains Mono', monospace;
  font-size: 12px;
  color: var(--accent-a);
  letter-spacing: 0.1em;
  margin-bottom: 18px;
}
.home-logo h1 {
  font-family: 'Clash Display', sans-serif;
  font-size: clamp(2.8rem, 8vw, 4.2rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  background: linear-gradient(135deg, #fff 20%, var(--accent-a) 60%, var(--accent-b) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  line-height: 1;
  margin-bottom: 10px;
}
.home-logo p {
  color: var(--muted);
  font-size: 15px;
  line-height: 1.6;
}

/* Difficulty picker */
.section-label {
  font-family: 'JetBrains Mono', monospace;
  font-size: 11px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 10px;
}
.diff-row {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
  margin-bottom: 28px;
}
.diff-btn {
  background: var(--glass);
  border: 1px solid var(--glass-border);
  border-radius: 14px;
  backdrop-filter: var(--blur);
  padding: 14px 10px;
  cursor: pointer;
  text-align: center;
  transition: all 0.2s;
  position: relative;
  overflow: hidden;
}
.diff-btn::before {
  content: '';
  position: absolute;
  inset: 0;
  background: var(--diff-color, var(--accent-a));
  opacity: 0;
  transition: opacity 0.2s;
}
.diff-btn:hover::before { opacity: 0.08; }
.diff-btn.selected { border-color: var(--diff-color, var(--accent-a)); }
.diff-btn.selected::before { opacity: 0.12; }
.diff-icon { font-size: 22px; margin-bottom: 6px; position: relative; }
.diff-name {
  font-family: 'Clash Display', sans-serif;
  font-size: 14px;
  font-weight: 600;
  color: var(--text);
  position: relative;
}
.diff-sub { font-size: 11px; color: var(--muted); margin-top: 2px; position: relative; }

/* Category grid */
.cat-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 10px;
  margin-bottom: 28px;
}
.cat-btn {
  background: var(--glass);
  border: 1px solid var(--glass-border);
  border-radius: 14px;
  backdrop-filter: var(--blur);
  padding: 16px;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 12px;
  transition: all 0.2s;
  position: relative;
  overflow: hidden;
  text-align: left;
}
.cat-btn::before {
  content: '';
  position: absolute;
  inset: 0;
  background: var(--cat-color, var(--accent-a));
  opacity: 0;
  transition: opacity 0.2s;
}
.cat-btn:hover::before { opacity: 0.08; }
.cat-btn.selected { border-color: var(--cat-color, var(--accent-a)); }
.cat-btn.selected::before { opacity: 0.12; }
.cat-icon {
  width: 40px; height: 40px;
  border-radius: 10px;
  display: flex; align-items: center; justify-content: center;
  font-size: 20px;
  background: rgba(255,255,255,0.07);
  flex-shrink: 0;
  position: relative;
}
.cat-info { position: relative; }
.cat-name { font-family: 'Clash Display', sans-serif; font-size: 14px; font-weight: 600; color: var(--text); }
.cat-count { font-size: 12px; color: var(--muted); margin-top: 2px; }

.start-btn {
  width: 100%;
  padding: 18px;
  border: none;
  border-radius: 14px;
  background: linear-gradient(135deg, var(--accent-a), var(--accent-b));
  color: #fff;
  font-family: 'Clash Display', sans-serif;
  font-size: 17px;
  font-weight: 600;
  cursor: pointer;
  letter-spacing: 0.02em;
  transition: transform 0.15s, box-shadow 0.15s, opacity 0.15s;
  box-shadow: 0 8px 32px rgba(99,102,241,0.35);
}
.start-btn:hover { transform: translateY(-2px); box-shadow: 0 14px 40px rgba(99,102,241,0.45); }
.start-btn:active { transform: scale(0.98); }
.start-btn:disabled { opacity: 0.4; cursor: not-allowed; transform: none; box-shadow: none; }

/* ─────────────────────────────────────────────
   QUIZ SCREEN
───────────────────────────────────────────── */
.quiz-top {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 16px;
}
.q-meta {
  font-family: 'JetBrains Mono', monospace;
  font-size: 12px;
  color: var(--muted);
}
.q-meta strong { color: var(--text); }
.score-pill {
  display: flex;
  align-items: center;
  gap: 8px;
  background: var(--glass);
  border: 1px solid var(--glass-border);
  backdrop-filter: var(--blur);
  border-radius: 100px;
  padding: 6px 14px;
  font-family: 'JetBrains Mono', monospace;
  font-size: 13px;
  color: var(--muted);
}
.score-val { color: var(--accent-d); font-size: 16px; font-weight: 500; }

.prog-track {
  height: 4px;
  background: rgba(255,255,255,0.08);
  border-radius: 100px;
  margin-bottom: 24px;
  overflow: hidden;
}
.prog-fill {
  height: 100%;
  border-radius: 100px;
  background: linear-gradient(90deg, var(--accent-a), var(--accent-b));
  transition: width 0.6s cubic-bezier(0.4,0,0.2,1);
}

/* Timer */
.timer-row {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 14px;
  margin-bottom: 22px;
}
.timer-wrap {
  position: relative;
  width: 68px; height: 68px;
}
.timer-wrap svg { transform: rotate(-90deg); }
.timer-wrap circle { fill: none; stroke-width: 3.5; stroke-linecap: round; }
.t-bg { stroke: rgba(255,255,255,0.08); }
.t-fg {
  stroke: var(--accent-a);
  stroke-dasharray: 188;
  stroke-dashoffset: 0;
  transition: stroke-dashoffset 1s linear, stroke 0.4s;
}
.timer-num {
  position: absolute; inset: 0;
  display: flex; align-items: center; justify-content: center;
  font-family: 'JetBrains Mono', monospace;
  font-size: 18px; font-weight: 500;
}
.diff-tag {
  background: var(--glass);
  border: 1px solid var(--glass-border);
  backdrop-filter: var(--blur);
  border-radius: 100px;
  padding: 5px 14px;
  font-family: 'JetBrains Mono', monospace;
  font-size: 12px;
}
.cat-tag {
  background: var(--glass);
  border: 1px solid var(--glass-border);
  backdrop-filter: var(--blur);
  border-radius: 100px;
  padding: 5px 14px;
  font-family: 'JetBrains Mono', monospace;
  font-size: 12px;
  color: var(--muted);
}

/* Question card */
.q-card {
  padding: 26px 24px 22px;
  margin-bottom: 16px;
  position: relative;
  overflow: hidden;
}
.q-card::before {
  content: '';
  position: absolute;
  top: -40px; right: -40px;
  width: 140px; height: 140px;
  background: radial-gradient(circle, rgba(167,139,250,0.15) 0%, transparent 70%);
  pointer-events: none;
}
.q-label {
  font-family: 'JetBrains Mono', monospace;
  font-size: 11px;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--accent-a);
  margin-bottom: 12px;
  opacity: 0.8;
}
.q-text {
  font-family: 'Clash Display', sans-serif;
  font-size: clamp(1rem, 2.8vw, 1.25rem);
  font-weight: 600;
  line-height: 1.4;
  color: var(--text);
}

/* Options */
.opts { display: grid; gap: 10px; margin-bottom: 16px; }
.opt {
  background: var(--glass);
  border: 1px solid var(--glass-border);
  backdrop-filter: var(--blur);
  border-radius: 14px;
  padding: 15px 18px;
  font-family: 'Cabinet Grotesk', sans-serif;
  font-size: 15px;
  font-weight: 500;
  color: var(--text);
  cursor: pointer;
  text-align: left;
  display: flex;
  align-items: center;
  gap: 14px;
  transition: border-color 0.15s, background 0.15s, transform 0.15s;
  position: relative;
  overflow: hidden;
}
.opt::after {
  content: '';
  position: absolute; inset: 0;
  background: linear-gradient(135deg, rgba(167,139,250,0.1), transparent);
  opacity: 0;
  transition: opacity 0.2s;
}
.opt:hover:not(:disabled)::after { opacity: 1; }
.opt:hover:not(:disabled) {
  border-color: rgba(167,139,250,0.45);
  transform: translateX(5px);
}
.opt:disabled { cursor: default; transform: none !important; }
.opt.correct { border-color: var(--correct); background: rgba(52,211,153,0.1); }
.opt.wrong { border-color: var(--wrong); background: rgba(251,113,133,0.1); }
.opt-key {
  width: 30px; height: 30px;
  border-radius: 8px;
  background: rgba(255,255,255,0.07);
  border: 1px solid rgba(255,255,255,0.1);
  display: flex; align-items: center; justify-content: center;
  font-family: 'JetBrains Mono', monospace;
  font-size: 12px;
  font-weight: 500;
  color: var(--muted);
  flex-shrink: 0;
  transition: all 0.15s;
}
.opt.correct .opt-key { background: var(--correct); color: #0a0a0f; border-color: var(--correct); }
.opt.wrong .opt-key { background: var(--wrong); color: #0a0a0f; border-color: var(--wrong); }

/* Feedback */
.fb {
  border-radius: 12px;
  padding: 12px 18px;
  font-family: 'JetBrains Mono', monospace;
  font-size: 13px;
  text-align: center;
  opacity: 0;
  transform: translateY(8px);
  transition: opacity 0.25s, transform 0.25s;
  margin-bottom: 6px;
}
.fb.show { opacity: 1; transform: translateY(0); }
.fb.ok { background: rgba(52,211,153,0.12); color: var(--correct); border: 1px solid rgba(52,211,153,0.25); }
.fb.bad { background: rgba(251,113,133,0.12); color: var(--wrong); border: 1px solid rgba(251,113,133,0.25); }

/* Streak badge */
.streak-badge {
  display: none;
  align-items: center;
  justify-content: center;
  gap: 6px;
  font-family: 'JetBrains Mono', monospace;
  font-size: 12px;
  color: var(--accent-e);
  margin-top: 10px;
  animation: popIn 0.3s cubic-bezier(0.34,1.56,0.64,1);
}
.streak-badge.show { display: flex; }
@keyframes popIn {
  from { opacity: 0; transform: scale(0.7); }
  to { opacity: 1; transform: scale(1); }
}

/* ─────────────────────────────────────────────
   RESULT SCREEN
───────────────────────────────────────────── */
.result-screen { text-align: center; }
.result-top { margin-bottom: 28px; }
.result-emoji { font-size: 52px; margin-bottom: 12px; display: block; animation: bounceIn 0.6s cubic-bezier(0.34,1.56,0.64,1); }
@keyframes bounceIn {
  from { opacity: 0; transform: scale(0.3); }
  to { opacity: 1; transform: scale(1); }
}
.result-grade {
  font-family: 'Clash Display', sans-serif;
  font-size: clamp(2rem, 6vw, 3rem);
  font-weight: 700;
  margin-bottom: 6px;
}
.result-subtitle { color: var(--muted); font-size: 15px; line-height: 1.6; }

.big-score {
  padding: 28px;
  margin-bottom: 20px;
  text-align: center;
}
.big-score-num {
  font-family: 'Clash Display', sans-serif;
  font-size: clamp(3.5rem, 10vw, 5rem);
  font-weight: 700;
  line-height: 1;
  background: linear-gradient(135deg, #fff 20%, var(--accent-a) 70%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.big-score-label { color: var(--muted); font-size: 14px; margin-top: 4px; font-family: 'JetBrains Mono', monospace; }

.stats-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 10px;
  margin-bottom: 20px;
}
.stat-g {
  padding: 16px 10px;
  border-radius: 14px;
}
.stat-g .sv {
  font-family: 'Clash Display', sans-serif;
  font-size: 1.6rem;
  font-weight: 700;
  line-height: 1;
  margin-bottom: 4px;
}
.stat-g .sl {
  font-family: 'JetBrains Mono', monospace;
  font-size: 10px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--muted);
}

.result-actions { display: flex; gap: 10px; }
.btn-ghost {
  flex: 1;
  padding: 16px;
  border: 1px solid var(--glass-border);
  border-radius: 14px;
  background: var(--glass);
  backdrop-filter: var(--blur);
  color: var(--muted);
  font-family: 'Clash Display', sans-serif;
  font-size: 15px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.15s;
}
.btn-ghost:hover { color: var(--text); border-color: rgba(255,255,255,0.25); }
.btn-main {
  flex: 2;
  padding: 16px;
  border: none;
  border-radius: 14px;
  background: linear-gradient(135deg, var(--accent-a), var(--accent-b));
  color: #fff;
  font-family: 'Clash Display', sans-serif;
  font-size: 15px;
  font-weight: 700;
  cursor: pointer;
  box-shadow: 0 8px 24px rgba(99,102,241,0.3);
  transition: transform 0.15s, box-shadow 0.15s;
}
.btn-main:hover { transform: translateY(-2px); box-shadow: 0 12px 32px rgba(99,102,241,0.4); }

/* Confetti canvas */
#confettiCanvas {
  position: fixed; inset: 0; pointer-events: none; z-index: 999;
}

/* Animations */
@keyframes shake {
  0%,100% { transform: translateX(0); }
  20%,60% { transform: translateX(-6px); }
  40%,80% { transform: translateX(6px); }
}
.shake { animation: shake 0.35s ease; }
@keyframes pulse {
  0%,100% { transform: scale(1); }
  50% { transform: scale(1.05); }
}
.pulse { animation: pulse 0.25s ease; }