.solution-step {
      display: flex; gap: 10px; align-items: flex-start;
      padding: 10px 12px; margin: 8px 0;
      background: #f8fafc; border: 1px solid #e2e8f0; border-radius: 12px;
    }
    .solution-step-label {
      display: grid; place-items: center; flex: 0 0 28px; min-height: 28px;
      padding: 0 5px; border-radius: 8px; background: #dbeafe;
      color: #1d4ed8; font-weight: 850; font-size: 12.5px;
    }
    .solution-conclusion {
      margin-top: 10px; padding: 11px 13px; border-radius: 12px;
      background: #ecfdf5; border: 1px solid #a7f3d0;
      color: #065f46; font-weight: 750;
    }
    .solution-paragraph { margin: 7px 2px; }
    .solution-check-list { display: grid; gap: 8px; margin: 8px 0; }
    .solution-check {
      display: grid; grid-template-columns: minmax(54px, auto) 1fr;
      gap: 10px; align-items: center; padding: 9px 11px;
      background: #f8fafc; border: 1px solid #e2e8f0; border-radius: 12px;
    }
    .solution-check-body { min-width: 0; }
    .solution-verdict {
      display: inline-flex; align-items: center; margin: 0 7px 3px 0;
      padding: 2px 8px; border-radius: 999px; font-size: 11.5px;
      line-height: 1.45; font-weight: 850; letter-spacing: .01em;
    }
    .solution-verdict.is-positive { color: #047857; background: #d1fae5; }
    .solution-verdict.is-negative { color: #b91c1c; background: #fee2e2; }
    .solution-verdict.is-neutral { color: #1d4ed8; background: #dbeafe; }
    .solution-check-label {
      color: #1d4ed8; font-weight: 800; text-align: center;
      padding-right: 10px; border-right: 1px solid #cbd5e1;
    }
    .solution-main-idea {
      margin: 2px 0 10px; padding: 10px 12px; border-radius: 12px;
      background: #eff6ff; border-left: 4px solid #3b82f6; font-weight: 700;
    }
    .solution-math-flow {
      margin: 8px 0; padding: 5px 13px;
      background: linear-gradient(90deg, #f8fbff 0%, #ffffff 100%);
      border-left: 3px solid #bfdbfe; border-radius: 4px 12px 12px 4px;
    }
    .solution-math-line {
      position: relative; padding: 8px 2px;
      border-bottom: 1px dashed #e2e8f0;
      overflow-x: auto;
    }
    .solution-math-line:last-child { border-bottom: 0; }
    .math-frac {
      display: inline-flex; flex-direction: column; align-items: center;
      vertical-align: middle; line-height: 1.05; margin: 0 .16em;
    }
    .math-frac > span:first-child { border-bottom: 1.5px solid currentColor; padding: 0 .18em .08em; }
    .math-frac > span:last-child { padding: .08em .18em 0; }
    .math-root { display: inline-flex; align-items: flex-start; vertical-align: middle; }
    .math-root-sign { font-size: 1.18em; line-height: 1; }
    .math-radicand { border-top: 1.5px solid currentColor; padding: 0 .12em; line-height: 1.12; }
    .math-expression sup, .math-expression sub { font-size: .72em; line-height: 0; }
    @media (max-width: 520px) {
      #resultCard { padding: 16px; border-radius: 18px; }
      .correct-answer { font-size: 17px; }
      .solution-box { padding: 13px; font-size: 15px; line-height: 1.58; }
      .solution-check { grid-template-columns: 42px minmax(0, 1fr); gap: 8px; padding: 9px; }
      .solution-check-label { padding-right: 7px; }
      .solution-main-idea { padding: 9px 10px; }
      .solution-math-flow { padding: 4px 10px; }
    }