/* ============================================================
       Reset & Base (matches pepstackr.com)
       ============================================================ */
    *, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
    html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }

    body {
      font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
      background: #0f172a;
      color: #e2e8f0;
      line-height: 1.6;
      overflow-x: hidden;
    }

    a { color: #38bdf8; text-decoration: none; transition: color 0.2s; }
    a:hover { color: #7dd3fc; }

    .container {
      max-width: 1120px;
      margin: 0 auto;
      padding: 0 24px;
    }

    /* ============================================================
       Navigation (identical to main site)
       ============================================================ */
    nav {
      position: fixed;
      top: 0;
      left: 0;
      right: 0;
      z-index: 100;
      background: rgba(15, 23, 42, 0.85);
      backdrop-filter: blur(16px);
      -webkit-backdrop-filter: blur(16px);
      border-bottom: 1px solid rgba(148, 163, 184, 0.08);
    }

    .nav-inner {
      max-width: 1120px;
      margin: 0 auto;
      padding: 0 24px;
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 64px;
    }

    .logo {
      display: flex;
      align-items: center;
      gap: 10px;
      font-weight: 700;
      font-size: 20px;
      color: #f8fafc;
      letter-spacing: -0.02em;
    }

    .logo-mark {
      width: 32px;
      height: 32px;
      background: linear-gradient(135deg, #22d3ee, #6366f1, #a855f7);
      border-radius: 8px;
      display: flex;
      align-items: center;
      justify-content: center;
    }

    .nav-links { display: flex; align-items: center; gap: 32px; }
    .nav-links a { color: #94a3b8; font-size: 14px; font-weight: 500; }
    .nav-links a:hover { color: #f1f5f9; }

    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      padding: 10px 24px;
      border-radius: 10px;
      font-weight: 600;
      font-size: 15px;
      border: none;
      cursor: pointer;
      transition: all 0.2s;
      text-decoration: none;
    }

    .btn-primary {
      background: linear-gradient(135deg, #0ea5e9, #6366f1);
      color: #fff;
      box-shadow: 0 4px 24px rgba(14, 165, 233, 0.25);
    }
    .btn-primary:hover {
      color: #fff;
      transform: translateY(-1px);
      box-shadow: 0 8px 32px rgba(14, 165, 233, 0.35);
    }

    .btn-ghost {
      background: rgba(148, 163, 184, 0.08);
      color: #e2e8f0;
      border: 1px solid rgba(148, 163, 184, 0.15);
    }
    .btn-ghost:hover {
      background: rgba(148, 163, 184, 0.15);
      color: #f8fafc;
    }

    .nav-cta { display: none; }
    @media (min-width: 640px) { .nav-cta { display: inline-flex; } }

    a.nav-login { color: #e2e8f0; font-weight: 600; }
    a.nav-login:hover { color: #fff; }

    .mobile-nav { display: flex; align-items: center; gap: 12px; }
    @media (min-width: 640px) { .mobile-nav { display: none; } }

    /* ============================================================
       Breadcrumb
       ============================================================ */
    .breadcrumb {
      padding: 88px 0 0;
      font-size: 13px;
      color: #64748b;
    }
    .breadcrumb a { color: #64748b; }
    .breadcrumb a:hover { color: #94a3b8; }
    .breadcrumb span { margin: 0 8px; }

    /* ============================================================
       Page Header
       ============================================================ */
    .page-header {
      padding: 24px 0 48px;
    }

    .page-header h1 {
      font-size: 36px;
      font-weight: 800;
      letter-spacing: -0.03em;
      color: #f8fafc;
      line-height: 1.2;
      margin-bottom: 12px;
    }

    .page-header .subtitle {
      font-size: 18px;
      color: #94a3b8;
      max-width: 640px;
    }

    @media (max-width: 640px) {
      .page-header h1 { font-size: 28px; }
      .page-header .subtitle { font-size: 16px; }
    }

    /* ============================================================
       Calculator Card
       ============================================================ */
    .calc-card {
      background: linear-gradient(135deg, rgba(30, 41, 59, 0.8), rgba(30, 41, 59, 0.4));
      border: 1px solid rgba(148, 163, 184, 0.1);
      border-radius: 16px;
      padding: 32px;
      margin-bottom: 48px;
    }

    @media (max-width: 640px) {
      .calc-card { padding: 20px; }
    }

    .calc-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 24px;
    }

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

    .input-group {
      display: flex;
      flex-direction: column;
      gap: 6px;
    }

    .input-group label {
      font-size: 13px;
      font-weight: 600;
      color: #94a3b8;
      text-transform: uppercase;
      letter-spacing: 0.05em;
    }

    .input-group select,
    .input-group input {
      background: rgba(15, 23, 42, 0.6);
      border: 1px solid rgba(148, 163, 184, 0.15);
      border-radius: 10px;
      padding: 12px 16px;
      font-size: 16px;
      color: #f8fafc;
      font-family: inherit;
      transition: border-color 0.2s;
      -webkit-appearance: none;
      appearance: none;
    }

    .input-group select {
      background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' fill='%2394a3b8'%3E%3Cpath d='M4 6l4 4 4-4'/%3E%3C/svg%3E");
      background-repeat: no-repeat;
      background-position: right 12px center;
      padding-right: 36px;
    }

    .input-group select:focus,
    .input-group input:focus {
      outline: none;
      border-color: #0ea5e9;
      box-shadow: 0 0 0 3px rgba(14, 165, 233, 0.15);
    }

    .input-group input::placeholder { color: #475569; }

    .input-row {
      display: flex;
      gap: 12px;
      align-items: flex-end;
    }

    .input-row .input-group { flex: 1; }

    .vial-buttons {
      display: flex;
      gap: 8px;
      flex-wrap: wrap;
    }

    .unit-toggle {
      display: flex;
      gap: 0;
      flex-shrink: 0;
      align-self: flex-end;
      margin-bottom: 2px;
    }

    .unit-btn {
      padding: 10px 14px;
      border: 1px solid rgba(148, 163, 184, 0.15);
      background: rgba(15, 23, 42, 0.6);
      color: #64748b;
      font-size: 14px;
      font-weight: 600;
      cursor: pointer;
      transition: all 0.2s;
      font-family: inherit;
    }

    .unit-btn:first-child {
      border-radius: 8px 0 0 8px;
      border-right: none;
    }

    .unit-btn:last-child {
      border-radius: 0 8px 8px 0;
    }

    .unit-btn.active {
      background: rgba(14, 165, 233, 0.15);
      border-color: #0ea5e9;
      color: #38bdf8;
    }

    .unit-btn:hover:not(.active) {
      color: #e2e8f0;
      border-color: rgba(148, 163, 184, 0.3);
    }

    .vial-btn {
      padding: 8px 16px;
      border-radius: 8px;
      border: 1px solid rgba(148, 163, 184, 0.15);
      background: rgba(15, 23, 42, 0.6);
      color: #94a3b8;
      font-size: 14px;
      font-weight: 500;
      cursor: pointer;
      transition: all 0.2s;
      font-family: inherit;
    }

    .vial-btn:hover {
      border-color: #0ea5e9;
      color: #e2e8f0;
    }

    .vial-btn.active {
      background: rgba(14, 165, 233, 0.15);
      border-color: #0ea5e9;
      color: #38bdf8;
    }

    /* ============================================================
       Results
       ============================================================ */
    .results {
      margin-top: 32px;
      padding-top: 32px;
      border-top: 1px solid rgba(148, 163, 184, 0.08);
      display: none;
    }

    .results.visible { display: block; }

    .results-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 16px;
    }

    @media (max-width: 640px) {
      .results-grid { grid-template-columns: 1fr; }
    }

    .result-card {
      background: rgba(15, 23, 42, 0.6);
      border: 1px solid rgba(148, 163, 184, 0.08);
      border-radius: 12px;
      padding: 20px;
      text-align: center;
    }

    .result-card .label {
      font-size: 12px;
      font-weight: 600;
      color: #64748b;
      text-transform: uppercase;
      letter-spacing: 0.05em;
      margin-bottom: 8px;
    }

    .result-card .value {
      font-size: 32px;
      font-weight: 800;
      letter-spacing: -0.02em;
    }

    .result-card .unit {
      font-size: 14px;
      color: #94a3b8;
      font-weight: 500;
      margin-top: 4px;
    }

    .result-primary .value { color: #38bdf8; }
    .result-secondary .value { color: #818cf8; }
    .result-tertiary .value { color: #22c55e; }

    .suggestions {
      margin-top: 24px;
    }

    .suggestions h3 {
      font-size: 14px;
      font-weight: 600;
      color: #94a3b8;
      margin-bottom: 12px;
    }

    .suggestion-table {
      width: 100%;
      border-collapse: collapse;
      font-size: 14px;
    }

    .suggestion-table th {
      text-align: left;
      font-weight: 600;
      color: #64748b;
      padding: 8px 12px;
      border-bottom: 1px solid rgba(148, 163, 184, 0.1);
      font-size: 12px;
      text-transform: uppercase;
      letter-spacing: 0.05em;
    }

    .suggestion-table td {
      padding: 10px 12px;
      border-bottom: 1px solid rgba(148, 163, 184, 0.05);
      color: #e2e8f0;
    }

    .suggestion-table tr:hover td {
      background: rgba(14, 165, 233, 0.05);
    }

    .suggestion-table .highlight {
      color: #38bdf8;
      font-weight: 600;
    }

    .suggestion-table tr.suggestion-highlight td {
      background: rgba(14, 165, 233, 0.12);
      color: #f1f5f9;
    }
    .suggestion-table tr.suggestion-highlight td strong {
      color: #38bdf8;
    }

    /* ============================================================
       CTA Card
       ============================================================ */
    .cta-card {
      background: linear-gradient(135deg, rgba(14, 165, 233, 0.12), rgba(99, 102, 241, 0.12));
      border: 1px solid rgba(14, 165, 233, 0.2);
      border-radius: 16px;
      padding: 32px;
      text-align: center;
      margin: 48px 0;
    }

    .cta-card h2 {
      font-size: 22px;
      font-weight: 700;
      color: #f8fafc;
      margin-bottom: 8px;
    }

    .cta-card p {
      color: #94a3b8;
      margin-bottom: 20px;
      font-size: 15px;
    }

    /* ============================================================
       Content Sections
       ============================================================ */
    .content-section {
      padding: 48px 0;
    }

    .content-section h2 {
      font-size: 24px;
      font-weight: 700;
      color: #f8fafc;
      margin-bottom: 16px;
      letter-spacing: -0.02em;
    }

    .content-section h3 {
      font-size: 18px;
      font-weight: 600;
      color: #f1f5f9;
      margin: 24px 0 8px;
    }

    .content-section p {
      color: #94a3b8;
      margin-bottom: 16px;
      line-height: 1.7;
    }

    .content-section ol,
    .content-section ul {
      color: #94a3b8;
      margin-bottom: 16px;
      padding-left: 24px;
      line-height: 1.7;
    }

    .content-section li { margin-bottom: 8px; }

    .divider {
      height: 1px;
      background: linear-gradient(90deg, transparent, rgba(148, 163, 184, 0.1), transparent);
      margin: 0;
    }

    /* ============================================================
       FAQ (matches main site)
       ============================================================ */
    .faq-list { margin-top: 24px; }

    .faq-item {
      border-bottom: 1px solid rgba(148, 163, 184, 0.08);
      padding: 20px 0;
    }

    .faq-item:last-child { border-bottom: none; }

    .faq-q {
      font-size: 16px;
      font-weight: 600;
      color: #f1f5f9;
      cursor: pointer;
      display: flex;
      justify-content: space-between;
      align-items: center;
      gap: 16px;
    }

    .faq-q::after {
      content: "+";
      font-size: 20px;
      color: #64748b;
      flex-shrink: 0;
      transition: transform 0.2s;
    }

    .faq-item.open .faq-q::after {
      content: "\2212";
    }

    .faq-a {
      display: none;
      padding-top: 12px;
      color: #94a3b8;
      line-height: 1.7;
    }

    .faq-item.open .faq-a { display: block; }

    /* ============================================================
       Related Links
       ============================================================ */
    .related-links {
      display: grid;
      grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
      gap: 16px;
      margin-top: 16px;
    }

    .related-card {
      background: rgba(30, 41, 59, 0.5);
      border: 1px solid rgba(148, 163, 184, 0.08);
      border-radius: 12px;
      padding: 20px;
      transition: all 0.2s;
    }

    .related-card:hover {
      border-color: rgba(14, 165, 233, 0.3);
      background: rgba(30, 41, 59, 0.7);
    }

    .related-card h4 {
      font-size: 15px;
      font-weight: 600;
      color: #f1f5f9;
      margin-bottom: 4px;
    }

    .related-card p {
      font-size: 13px;
      color: #64748b;
      margin: 0;
    }

    /* ============================================================
       Footer (identical to main site)
       ============================================================ */
    footer {
      padding: 48px 0;
      border-top: 1px solid rgba(148, 163, 184, 0.06);
    }

    .footer-inner {
      display: flex;
      align-items: center;
      justify-content: space-between;
      flex-wrap: wrap;
      gap: 16px;
    }

    .footer-copy {
      font-size: 13px;
      color: #475569;
    }

    .footer-links { display: flex; gap: 24px; }
    .footer-links a { font-size: 13px; color: #64748b; }
    .footer-links a:hover { color: #94a3b8; }