/* ═══════════════════════════════════════════
   MCQ DRILL — Shared Styles
   ═══════════════════════════════════════════ */

@import url('https://fonts.googleapis.com/css2?family=Space+Grotesk:wght@400;500;600;700&family=IBM+Plex+Mono:wght@400;600&display=swap');

:root {
  --bg:       #0d0d0d;
  --surface:  #141414;
  --card:     #1a1a1a;
  --border:   #2a2a2a;
  --text:     #f0f0f0;
  --muted:    #666;
  --mono:     'IBM Plex Mono', monospace;
  --sans:     'Space Grotesk', sans-serif;

  /* Unit accent colours */
  --u1:       #f97316;   /* orange */
  --u2:       #22d3ee;   /* cyan   */
  --u3:       #a78bfa;   /* violet */

  --green:    #4ade80;
  --red:      #f87171;
  --yellow:   #fbbf24;
}

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

html { scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--sans);
  min-height: 100vh;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

/* ── noise texture overlay ── */
body::after {
  content: '';
  position: fixed; inset: 0;
  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; z-index: 999; opacity: 0.35;
}

a { color: inherit; text-decoration: none; }
button { cursor: pointer; font-family: var(--sans); }

/* ── utility ── */
.hidden { display: none !important; }

/* ── top nav bar ── */
.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1.1rem 2rem;
  border-bottom: 1px solid var(--border);
  position: sticky; top: 0;
  background: rgba(13,13,13,0.92);
  backdrop-filter: blur(12px);
  z-index: 100;
}

.topbar-logo {
  display: flex; align-items: center; gap: 0.6rem;
  font-size: 1.1rem; font-weight: 700; letter-spacing: -0.02em;
}
.topbar-logo .dot {
  width: 10px; height: 10px; border-radius: 50%;
  background: var(--accent, #f97316);
  box-shadow: 0 0 10px var(--accent, #f97316);
  flex-shrink: 0;
}

.topbar-back {
  font-family: var(--mono);
  font-size: 0.78rem;
  color: var(--muted);
  padding: 0.45rem 0.9rem;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: transparent;
  transition: all 0.2s;
  text-decoration: none;
  display: inline-flex; align-items: center; gap: 0.4rem;
}
.topbar-back:hover { color: var(--text); border-color: var(--muted); }

/* ── page wrapper ── */
.page { max-width: 820px; margin: 0 auto; padding: 2.5rem 1.5rem 4rem; }

/* ── cards ── */
.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 1.75rem;
}

/* ── buttons ── */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 0.5rem;
  padding: 0.85rem 1.75rem;
  border-radius: 10px;
  font-size: 0.95rem; font-weight: 600;
  border: none;
  transition: all 0.2s;
}
.btn-primary {
  background: var(--accent, #f97316);
  color: #000;
}
.btn-primary:hover { filter: brightness(1.1); transform: translateY(-1px); }
.btn-outline {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text);
}
.btn-outline:hover { border-color: var(--accent, #f97316); color: var(--accent, #f97316); }
.btn-full { width: 100%; }

/* ── progress bar ── */
.prog-wrap {
  height: 3px; background: var(--border);
  border-radius: 3px; overflow: hidden;
  margin-bottom: 2rem;
}
.prog-fill {
  height: 100%;
  background: var(--accent, #f97316);
  border-radius: 3px;
  transition: width 0.35s ease;
}

/* ── score chip ── */
.chip {
  display: inline-flex; align-items: center; gap: 0.35rem;
  font-family: var(--mono); font-size: 0.78rem;
  padding: 0.3rem 0.7rem;
  border-radius: 6px;
  border: 1px solid var(--border);
  background: var(--surface);
}
.chip.correct { border-color: rgba(74,222,128,0.3); color: var(--green); }
.chip.wrong   { border-color: rgba(248,113,113,0.3); color: var(--red); }

/* ── animations ── */
@keyframes fadeUp {
  from { opacity: 0; transform: translateY(12px); }
  to   { opacity: 1; transform: translateY(0); }
}
.fade-up { animation: fadeUp 0.35s ease forwards; }

@keyframes pop {
  0%   { transform: scale(1); }
  50%  { transform: scale(1.04); }
  100% { transform: scale(1); }
}