:root {
    --soa-xi-primary: #6c3fc5;
    --soa-xi-accent: #f7b731;
    --soa-xi-dark: #0d0d1a;
    --soa-xi-card-bg: #1a1a2e;
    --soa-xi-text: #e0e0f0;
    --soa-xi-muted: #9a9abf;
    --soa-xi-glow: rgba(108, 63, 197, .45);
    --soa-xi-gradient: linear-gradient(135deg, #6c3fc5 0%, #3a1c8c 50%, #0d0d1a 100%);
  }

  * { box-sizing: border-box; margin: 0; padding: 0; }
  body { background: var(--soa-xi-dark); color: var(--soa-xi-text); font-family: 'Segoe UI', sans-serif; }

  /* NAV */
  .soa-xi-nav { background: rgba(13,13,26,.97); backdrop-filter: blur(12px); border-bottom: 1px solid rgba(108,63,197,.2); padding: 1rem 0; position: sticky; top: 0; z-index: 100; }
  .soa-xi-nav-brand { font-weight: 800; font-size: 1.2rem; color: #fff; text-decoration: none; display: flex; align-items: center; gap: 8px; }
  .soa-xi-nav-brand span { color: var(--soa-xi-accent); }
  .soa-xi-nav-link { color: var(--soa-xi-muted) !important; font-size: .88rem; text-decoration: none; margin-left: 1.5rem; transition: color .2s; }
  .soa-xi-nav-link:hover { color: var(--soa-xi-accent) !important; }

  /* HERO */
  .soa-xi-hero { background: var(--soa-xi-gradient); padding: 5rem 0 4rem; position: relative; overflow: hidden; }
  .soa-xi-hero::before { content: ''; position: absolute; width: 600px; height: 600px; background: radial-gradient(circle, rgba(108,63,197,.2) 0%, transparent 70%); top: -180px; right: -120px; border-radius: 50%; }
  .soa-xi-hero-badge { display: inline-block; background: rgba(247,183,49,.15); border: 1px solid var(--soa-xi-accent); color: var(--soa-xi-accent); padding: 5px 16px; border-radius: 50px; font-size: .75rem; letter-spacing: 2px; text-transform: uppercase; margin-bottom: 1.1rem; }
  .soa-xi-hero-title { font-size: clamp(1.9rem, 4.5vw, 3.4rem); font-weight: 800; color: #fff; line-height: 1.2; }
  .soa-xi-hero-title span { background: linear-gradient(90deg, var(--soa-xi-accent), #ff7eb3); -webkit-background-clip: text; -webkit-text-fill-color: transparent; }
  .soa-xi-hero-sub { color: var(--soa-xi-muted); font-size: 1rem; margin: 1rem 0 1.8rem; max-width: 520px; }

  /* ATOM ANIMATION */
  .soa-xi-atom-wrap { display: flex; justify-content: center; align-items: center; }
  .soa-xi-atom { position: relative; width: 240px; height: 240px; }
  .soa-xi-nucleus { position: absolute; top: 50%; left: 50%; transform: translate(-50%,-50%); width: 46px; height: 46px; background: radial-gradient(circle, #f7b731, #e85d04); border-radius: 50%; box-shadow: 0 0 26px #f7b731aa; z-index: 2; }
  .soa-xi-orbit { position: absolute; top: 50%; left: 50%; border: 2px solid rgba(108,63,197,.5); border-radius: 50%; animation: soa-xi-spin linear infinite; }
  .soa-xi-orbit:nth-child(2) { width: 110px; height: 110px; margin: -55px 0 0 -55px; animation-duration: 3s; }
  .soa-xi-orbit:nth-child(3) { width: 170px; height: 170px; margin: -85px 0 0 -85px; animation-duration: 5s; border-color: rgba(247,183,49,.4); }
  .soa-xi-orbit:nth-child(4) { width: 230px; height: 230px; margin: -115px 0 0 -115px; animation-duration: 8s; border-color: rgba(108,63,197,.3); }
  .soa-xi-electron { position: absolute; width: 11px; height: 11px; background: #a78bfa; border-radius: 50%; box-shadow: 0 0 8px #a78bfa; top: -5px; left: 50%; margin-left: -5px; }
  @keyframes soa-xi-spin { from { transform: translate(-50%,-50%) rotate(0deg); } to { transform: translate(-50%,-50%) rotate(360deg); } }

  /* STATS */
  .soa-xi-stats-bar { background: var(--soa-xi-card-bg); border-top: 1px solid rgba(108,63,197,.3); border-bottom: 1px solid rgba(108,63,197,.3); padding: 1.5rem 0; }
  .soa-xi-stat-item { text-align: center; }
  .soa-xi-stat-num { font-size: 2rem; font-weight: 800; background: linear-gradient(90deg, var(--soa-xi-accent), #a78bfa); -webkit-background-clip: text; -webkit-text-fill-color: transparent; }
  .soa-xi-stat-label { font-size: .78rem; color: var(--soa-xi-muted); letter-spacing: 1px; }

  /* TAGS */
  .soa-xi-tag { display: inline-block; padding: 4px 12px; border-radius: 7px; font-size: .72rem; font-weight: 700; margin: 2px; letter-spacing: .4px; }
  .soa-xi-tag-jee    { background: rgba(99,102,241,.2);  color: #818cf8; border: 1px solid #4f46e5; }
  .soa-xi-tag-neet   { background: rgba(16,185,129,.2);  color: #34d399; border: 1px solid #059669; }
  .soa-xi-tag-aiims  { background: rgba(239,68,68,.2);   color: #f87171; border: 1px solid #dc2626; }
  .soa-xi-tag-bitsat { background: rgba(168,85,247,.2);  color: #c084fc; border: 1px solid #9333ea; }
  .soa-xi-tag-kvpy   { background: rgba(20,184,166,.2);  color: #2dd4bf; border: 1px solid #0d9488; }

  /* SECTION */
  .soa-xi-section { padding: 70px 0; }
  .soa-xi-section-title { font-size: 2rem; font-weight: 800; color: #fff; margin-bottom: .5rem; }
  .soa-xi-section-title span { color: var(--soa-xi-accent); }
  .soa-xi-divider { width: 60px; height: 4px; background: linear-gradient(90deg, var(--soa-xi-primary), var(--soa-xi-accent)); border-radius: 2px; margin: .8rem 0 2.5rem; }

  /* FILTER */
  .soa-xi-filter-btn { background: rgba(108,63,197,.15); border: 1px solid rgba(108,63,197,.35); color: var(--soa-xi-muted); padding: 7px 18px; border-radius: 50px; font-size: .82rem; cursor: pointer; transition: all .25s; }
  .soa-xi-filter-btn:hover, .soa-xi-filter-btn.active { background: var(--soa-xi-primary); color: #fff; border-color: var(--soa-xi-primary); box-shadow: 0 0 16px var(--soa-xi-glow); }

  /* Q CARD */
  .soa-xi-q-card { background: var(--soa-xi-card-bg); border: 1px solid rgba(108,63,197,.22); border-radius: 16px; padding: 1.4rem 1.5rem; height: 100%; transition: border-color .3s, box-shadow .3s; display: flex; flex-direction: column; }
  .soa-xi-q-card:hover { border-color: var(--soa-xi-primary); box-shadow: 0 8px 32px var(--soa-xi-glow); }
  .soa-xi-q-num { font-size: .7rem; font-weight: 700; color: var(--soa-xi-accent); letter-spacing: 1px; margin: .5rem 0 .4rem; text-transform: uppercase; }
  .soa-xi-q-text { font-size: .93rem; color: #fff; font-weight: 600; line-height: 1.6; margin-bottom: 1rem; flex-grow: 1; }
  .soa-xi-q-label { color: var(--soa-xi-accent); font-weight: 700; margin-right: 6px; }

  /* OPTIONS */
  .soa-xi-opt { background: rgba(255,255,255,.04); border: 1px solid rgba(255,255,255,.08); border-radius: 9px; padding: 9px 14px; margin-bottom: 7px; font-size: .84rem; color: var(--soa-xi-muted); line-height: 1.5; cursor: pointer; transition: all .2s; }
  .soa-xi-opt:hover { border-color: var(--soa-xi-primary); color: var(--soa-xi-text); background: rgba(108,63,197,.12); }
  .soa-xi-opt.correct { border-color: #10b981 !important; background: rgba(16,185,129,.18) !important; color: #34d399 !important; }
  .soa-xi-opt.wrong   { border-color: #ef4444 !important; background: rgba(239,68,68,.15)  !important; color: #f87171 !important; }

  /* ── TIMER pulse animation ── */
  @keyframes soa-pulse {
    0%,100% { opacity:1; }
    50%      { opacity:.3; }
  }
  .soa-timer-dot {
    display:inline-block; width:6px; height:6px;
    background:#34d399; border-radius:50%; margin-right:4px;
    animation: soa-pulse 1.2s ease-in-out infinite;
    vertical-align:middle;
  }
     MathJax renders into <mjx-container> with its own SVG/CHTML output.
     By default it uses currentColor but some browsers compute it as black.
     Force all MathJax output to inherit the surrounding element's color. */
  mjx-container,
  mjx-container * ,
  mjx-container svg,
  mjx-container svg * { color: inherit !important; fill: currentColor !important; }

  /* Question text math = white */
  .soa-xi-q-text mjx-container,
  .soa-xi-q-text mjx-container * { color: #fff !important; fill: #fff !important; }

  /* Option math = muted by default, inherits hover/selected color */
  .soa-xi-opt mjx-container,
  .soa-xi-opt mjx-container * { color: inherit !important; fill: currentColor !important; }

  /* Selected option math = white */
  .soa-xi-opt.selected mjx-container,
  .soa-xi-opt.selected mjx-container * { color: var(--soa-xi-text) !important; fill: var(--soa-xi-text) !important; }

  /* REVEAL BTN */
  .soa-xi-reveal-btn { display: inline-block; margin-top: .9rem; padding: 6px 18px; background: transparent; border: 1.5px solid var(--soa-xi-accent); color: var(--soa-xi-accent); border-radius: 50px; font-size: .76rem; font-weight: 700; cursor: pointer; transition: all .25s; }
  .soa-xi-reveal-btn:hover { background: var(--soa-xi-accent); color: #000; }

  /* ANSWER BOX */
  .soa-xi-answer-box { display: none; margin-top: .8rem; background: rgba(108,63,197,.12); border: 1px solid rgba(108,63,197,.4); border-radius: 10px; padding: .75rem 1rem; font-size: .84rem; color: var(--soa-xi-text); animation: soa-xi-fadein .3s ease; }
  @keyframes soa-xi-fadein { from { opacity: 0; transform: translateY(5px); } to { opacity: 1; transform: none; } }

  /* SCORE BAR */
  .soa-xi-score-bar { background: rgba(108,63,197,.1); border: 1px solid rgba(108,63,197,.25); border-radius: 10px; padding: .7rem 1.2rem; font-size: .9rem; color: var(--soa-xi-text); display: flex; flex-wrap: wrap; align-items: center; gap: .5rem; margin-bottom: 1.5rem; }
  .soa-xi-score-bar strong { color: var(--soa-xi-accent); }

  /* PROGRESS */
  .soa-xi-progress-wrap { margin-bottom: 1.1rem; }
  .soa-xi-progress-label { display: flex; justify-content: space-between; margin-bottom: 5px; }
  .soa-xi-progress-label span:first-child { font-size: .88rem; color: var(--soa-xi-text); }
  .soa-xi-progress-label span:last-child  { font-size: .82rem; color: var(--soa-xi-accent); font-weight: 700; }
  .soa-xi-progress-bar-bg   { height: 7px; border-radius: 4px; background: rgba(255,255,255,.08); overflow: hidden; }
  .soa-xi-progress-bar-fill { height: 100%; border-radius: 4px; background: linear-gradient(90deg, var(--soa-xi-primary), var(--soa-xi-accent)); }

  /* TAKEAWAY */
  .soa-xi-takeaway-item { display: flex; gap: 1rem; align-items: flex-start; background: var(--soa-xi-card-bg); border: 1px solid rgba(108,63,197,.2); border-radius: 13px; padding: 1.1rem 1.3rem; margin-bottom: .9rem; transition: border-color .3s; }
  .soa-xi-takeaway-item:hover { border-color: var(--soa-xi-accent); }

  /* STEP */
  .soa-xi-step { display: flex; gap: 1.1rem; align-items: flex-start; margin-bottom: 1.3rem; }
  .soa-xi-step-num { width: 40px; height: 40px; border-radius: 50%; background: linear-gradient(135deg, var(--soa-xi-primary), #a78bfa); display: flex; align-items: center; justify-content: center; font-weight: 800; font-size: .95rem; flex-shrink: 0; color: #fff; }
  .soa-xi-step-title { font-weight: 700; color: #fff; margin-bottom: .2rem; }
  .soa-xi-step-text  { font-size: .86rem; color: var(--soa-xi-muted); }

  /* CARD */
  .soa-xi-card { background: var(--soa-xi-card-bg); border: 1px solid rgba(108,63,197,.22); border-radius: 16px; padding: 1.5rem 1.4rem; transition: all .3s; height: 100%; }
  .soa-xi-card:hover { border-color: var(--soa-xi-primary); box-shadow: 0 10px 36px var(--soa-xi-glow); }
  .soa-xi-card-icon  { width: 50px; height: 50px; border-radius: 13px; display: flex; align-items: center; justify-content: center; font-size: 1.35rem; margin-bottom: .9rem; }
  .soa-xi-card-title { font-size: .98rem; font-weight: 700; color: #fff; margin-bottom: .4rem; }
  .soa-xi-card-text  { font-size: .83rem; color: var(--soa-xi-muted); }
  .soa-xi-stars      { color: var(--soa-xi-accent); font-size: .78rem; margin-top: .5rem; }
  .soa-xi-pill { display: inline-block; background: rgba(108,63,197,.2); border: 1px solid rgba(108,63,197,.4); color: #c4b5fd; padding: 3px 10px; border-radius: 18px; font-size: .72rem; margin: 2px; }

  /* BTNS */
  .soa-xi-btn-primary { background: var(--soa-xi-primary); color: #fff; border: none; padding: 13px 34px; border-radius: 50px; font-weight: 700; font-size: .98rem; cursor: pointer; transition: all .3s; box-shadow: 0 0 22px var(--soa-xi-glow); text-decoration: none; display: inline-block; }
  .soa-xi-btn-primary:hover { transform: translateY(-3px); box-shadow: 0 0 38px var(--soa-xi-glow); color: #fff; }
  .soa-xi-btn-outline { background: transparent; color: var(--soa-xi-accent); border: 2px solid var(--soa-xi-accent); padding: 11px 30px; border-radius: 50px; font-weight: 700; font-size: .98rem; cursor: pointer; transition: all .3s; text-decoration: none; display: inline-block; }
  .soa-xi-btn-outline:hover { background: var(--soa-xi-accent); color: #000; }

  /* CTA */
  .soa-xi-cta { background: linear-gradient(135deg, #1a0a3c, #2d1b69); border: 1px solid rgba(108,63,197,.4); border-radius: 22px; padding: 3rem 2rem; text-align: center; }

  /* FOOTER */
  .soa-xi-footer { background: #080810; border-top: 1px solid rgba(108,63,197,.2); padding: 1.4rem 0; text-align: center; color: var(--soa-xi-muted); font-size: .82rem; }

  .soa-xi-count-badge { display: inline-block; background: rgba(247,183,49,.12); border: 1px solid rgba(247,183,49,.35); color: var(--soa-xi-accent); padding: 4px 14px; border-radius: 20px; font-size: .78rem; font-weight: 700; margin-left: 10px; vertical-align: middle; }

  /* No results */
  .soa-xi-no-results { background: rgba(108,63,197,.08); border: 1px solid rgba(108,63,197,.25); border-radius: 12px; padding: 1.5rem; text-align: center; color: var(--soa-xi-muted); display: none; }
  .soa-xi-no-results.show { display: block; }