*, *::before, *::after { box-sizing: border-box; }
:root {
  color-scheme: light;
  --primary: #7c3aed;
  --primary-hover: #6d28d9;
}
[data-topnav] {
  background: #fff;
  border-bottom: 1px solid var(--border);
  padding: 0.75rem 1rem;
  display: flex;
  align-items: center;
  gap: 1rem;
  position: sticky;
  top: 0;
  z-index: 201;
}
[data-topnav] .logo {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-weight: 700;
  font-size: 1.125rem;
  color: var(--foreground);
  text-decoration: none;
  flex-shrink: 0;
}
[data-topnav] .logo img { height: 28px; }
.search-container {
  flex: 1;
  max-width: 400px;
  position: relative;
}
.search-container input {
  width: 100%;
  padding: 0.5rem 1rem 0.5rem 2.5rem;
  border: 1px solid var(--border);
  border-radius: 0.5rem;
  font-size: 0.875rem;
  background: var(--background-alt);
}
.search-container input:focus {
  outline: none;
  border-color: var(--primary);
  background: #fff;
}
.search-container::before {
  content: "🔍";
  position: absolute;
  left: 0.75rem;
  top: 50%;
  transform: translateY(-50%);
  font-size: 0.875rem;
}
.nav-links {
  display: flex;
  gap: 1rem;
  margin-left: auto;
}
.nav-links a {
  color: var(--foreground-light);
  font-size: 0.875rem;
  text-decoration: none;
  white-space: nowrap;
}
.nav-links a:hover { color: var(--foreground); }
.nav-links a.active { color: var(--foreground); font-weight: 500; }
.mobile-menu-btn {
  display: none;
  background: none;
  border: none;
  font-size: 1.5rem;
  cursor: pointer;
  padding: 0.25rem;
  color: var(--foreground);
}
.search-toggle-btn {
  display: none;
  background: none;
  border: none;
  font-size: 1rem;
  cursor: pointer;
  padding: 0.25rem;
}
.account-menu { position: relative; }
.account-btn {
  background: none;
  border: none;
  cursor: pointer;
  padding: 0;
  border-radius: 50%;
}
.account-avatar {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  display: block;
}
.account-dropdown {
  display: none;
  position: absolute;
  top: 100%;
  right: 0;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 0.5rem;
  padding: 0.5rem;
  min-width: 180px;
  box-shadow: 0 4px 12px rgba(0,0,0,0.1);
  z-index: 102;
}
.account-dropdown a {
  display: block;
  padding: 0.5rem 0.75rem;
  color: var(--foreground);
  text-decoration: none;
  font-size: 0.875rem;
  border-radius: 0.25rem;
}
.account-dropdown a:hover { background: var(--border); }
.account-menu.open .account-dropdown { display: block; }
.sidebar-overlay {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0,0,0,0.4);
  z-index: 90;
}
.sidebar-overlay.active { display: block; }
.hero {
  text-align: center;
  padding: 2rem 1rem;
}
.hero h1 {
  font-size: 2rem;
  margin-bottom: 0.5rem;
}
.hero p {
  color: var(--foreground-light);
  max-width: 500px;
  margin: 0 auto;
}


@media (max-width: 768px) {
  [data-topnav] { flex-wrap: wrap; gap: 0.5rem; padding: 0.5rem 1rem; }
  .search-toggle-btn { display: block; }
  .search-container { display: none; order: 5; max-width: 100%; width: 100%; flex-basis: 100%; }
  .search-container.search-open { display: block; }
  .search-container input { width: 100%; }
  .right-menu-btn { margin-left: auto; }
  .account-menu { margin-left: 0.5rem; }
  .nav-links { display: none; }
  .mobile-menu-btn { display: block; }
  .nav-links.mobile-open {
    display: flex;
    flex-direction: column;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: #fff;
    padding: 1rem;
    border-bottom: 1px solid var(--border);
    gap: 0.75rem;
    z-index: 201;
  }
  .sidebar-overlay.active { display: block; }
  .hero { padding: 1.5rem 0.5rem; }
  .hero h1 { font-size: 1.5rem; }
  .hero p { font-size: 0.9375rem; }
  footer .footer-content { flex-direction: column; gap: 1.5rem; }
  footer .footer-brand { max-width: 100%; }
  footer .footer-links { gap: 1.5rem; }
}
@media (max-width: 480px) {
  [data-topnav] { padding: 0.5rem 0.75rem; }
  .hero h1 { font-size: 1.375rem; }
  footer .footer-links { flex-direction: column; gap: 1.25rem; }
  footer .footer-bottom { flex-direction: column; text-align: center; }
}

.hero {
      text-align: center;
      padding: 2rem 1rem;
    }
    .hero h1 {
      font-size: 2rem;
      margin-bottom: 0.5rem;
    }
    .hero p {
      color: var(--foreground-light);
      max-width: 500px;
      margin: 0 auto;
    }

    .page-wrap {
      max-width: 1200px;
      margin: 0 auto;
      padding: 1.5rem 1rem 2rem;
    }

        .tab-bar {
      display: flex;
      gap: 0;
      margin-bottom: 1.5rem;
      border-bottom: 1px solid var(--border);
      overflow-x: auto;
      white-space: nowrap;
      -webkit-overflow-scrolling: touch;
      scrollbar-width: none;
    }
    .tab-bar::-webkit-scrollbar { display: none; }
    .tab-btn { flex-shrink: 0; flex-shrink: 0; }
    .tab-btn { flex-shrink: 0;
      padding: 0.75rem 1.5rem;
      background: none;
      border: none;
      color: var(--foreground-light);
      font-size: 0.9375rem;
      cursor: pointer;
      border-bottom: 2px solid transparent;
      transition: color 0.2s, border-color 0.2s;
    }
    .tab-btn:hover { color: var(--foreground); }
    .tab-btn.active {
      color: var(--primary);
      border-bottom-color: var(--primary);
      font-weight: 600;
    }
    .tab-pane { display: none; }
    .tab-pane.active { display: block; }

    .calc-layout {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 1.5rem;
      align-items: start;
    }
    @media (max-width: 900px) {
      .calc-layout { grid-template-columns: 1fr; }
    }

    .calc-card {
      border: 1px solid var(--border);
      border-radius: 0.5rem;
      padding: 1.25rem;
    }
    .calc-card h2 {
      font-size: 1.125rem;
      font-weight: 600;
      margin: 0 0 1rem;
      display: flex;
      align-items: center;
      gap: 0.5rem;
    }
    .calc-card h2 .badge {
      font-size: 0.625rem;
      text-transform: uppercase;
      letter-spacing: 0.05em;
      padding: 0.125rem 0.5rem;
      border-radius: 999px;
      background: var(--primary);
      color: #fff;
      opacity: 0.85;
    }

    .form-group { margin-bottom: 1rem; }
    .form-group label {
      display: block;
      font-size: 0.8125rem;
      color: var(--foreground-light);
      margin-bottom: 0.375rem;
      font-weight: 500;
    }
    .form-group .input-wrap { position: relative; }
    .form-group .input-wrap .prefix {
      position: absolute;
      left: 0.75rem;
      top: 50%;
      transform: translateY(-50%);
      color: var(--foreground-light);
      font-size: 0.8125rem;
      pointer-events: none;
    }
    .form-group .input-wrap .suffix {
      position: absolute;
      right: 0.75rem;
      top: 50%;
      transform: translateY(-50%);
      color: var(--foreground-light);
      font-size: 0.8125rem;
      pointer-events: none;
    }
    .form-group input[type="number"] {
      width: 100%;
      padding: 0.5rem 0.75rem 0.5rem 1.75rem;
      border: 1px solid var(--border);
      border-radius: 0.375rem;
      font-size: 0.9375rem;
      -moz-appearance: textfield;
    }
    .form-group input[type="number"]:focus {
      outline: none;
      border-color: var(--primary);
    }
    .form-group input[type="number"]::-webkit-outer-spin-button,
    .form-group input[type="number"]::-webkit-inner-spin-button {
      -webkit-appearance: none;
      margin: 0;
    }
    .form-group input[type="range"] {
      width: 100%;
      margin-top: 0.25rem;
    }
    .range-labels {
      display: flex;
      justify-content: space-between;
      font-size: 0.6875rem;
      color: var(--foreground-light);
      margin-top: 0.125rem;
    }

    .calc-btn {
      width: 100%;
      margin-top: 0.5rem;
    }

    .results-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 0.75rem;
      margin: 1rem 0;
    }
    .result-item {
      border: 1px solid var(--border);
      border-radius: 0.5rem;
      padding: 1rem;
      text-align: center;
    }
    .result-item .ri-label {
      font-size: 0.6875rem;
      text-transform: uppercase;
      letter-spacing: 0.05em;
      color: var(--foreground-light);
      margin-bottom: 0.25rem;
    }
    .result-item .ri-value {
      font-size: 1.375rem;
      font-weight: 700;
    }
    .result-item .ri-value.primary { color: var(--primary); }
    .result-item .ri-value.green { color: #059669; }
    .result-item .ri-value.amber { color: #d97706; }
    .result-item .ri-value.blue { color: #2563eb; }
    .result-item.full { grid-column: 1 / -1; }

    .chart-wrap {
      display: flex;
      justify-content: center;
      margin: 1rem 0;
      position: relative;
    }
    .chart-wrap canvas { max-width: 200px; max-height: 200px; }
    .chart-center {
      position: absolute;
      top: 50%;
      left: 50%;
      transform: translate(-50%, -50%);
      text-align: center;
      pointer-events: none;
    }
    .chart-center .cc-label {
      font-size: 0.625rem;
      color: var(--foreground-light);
      text-transform: uppercase;
      letter-spacing: 0.05em;
    }
    .chart-center .cc-value {
      font-size: 1.125rem;
      font-weight: 700;
    }

    .legend {
      display: flex;
      gap: 1.5rem;
      justify-content: center;
      flex-wrap: wrap;
      margin-bottom: 0.5rem;
    }
    .legend-item {
      display: flex;
      align-items: center;
      gap: 0.375rem;
      font-size: 0.75rem;
      color: var(--foreground-light);
    }
    .legend-item .dot {
      width: 10px;
      height: 10px;
      border-radius: 50%;
      flex-shrink: 0;
    }

    .table-section { margin-top: 1.25rem; }
    .table-section h3 {
      font-size: 0.9375rem;
      font-weight: 600;
      margin: 0 0 0.75rem;
      display: flex;
      align-items: center;
      gap: 0.5rem;
    }
    .table-controls {
      display: flex;
      gap: 0.5rem;
      align-items: center;
      flex-wrap: wrap;
      margin-bottom: 0.75rem;
    }
    .table-controls label { font-size: 0.8125rem; color: var(--foreground-light); }
    .table-controls input[type="number"] {
      width: 80px;
      padding: 0.25rem 0.5rem;
      border: 1px solid var(--border);
      border-radius: 0.375rem;
      font-size: 0.8125rem;
    }
    .table-controls select {
      padding: 0.25rem 0.5rem;
      border: 1px solid var(--border);
      border-radius: 0.375rem;
      font-size: 0.8125rem;
    }

    .table-wrap {
      overflow-x: auto;
      max-height: 400px;
      overflow-y: auto;
      border: 1px solid var(--border);
      border-radius: 0.5rem;
    }
    .table-wrap table { width: 100%; border-collapse: collapse; font-size: 0.8125rem; }
    .table-wrap th {
      position: sticky;
      top: 0;
      background: #fff;
      z-index: 1;
      padding: 0.5rem 0.75rem;
      text-align: right;
      font-weight: 600;
      border-bottom: 1px solid var(--border);
      white-space: nowrap;
    }
    .table-wrap th:first-child { text-align: left; }
    .table-wrap td {
      padding: 0.375rem 0.75rem;
      text-align: right;
      border-bottom: 1px solid var(--border);
    }
    .table-wrap td:first-child { text-align: left; color: var(--foreground-light); }
    .table-wrap tbody tr:hover td { background: var(--background-alt); }
    .table-wrap tbody tr:last-child td { border-bottom: none; }

    .info-section {
      margin-top: 2rem;
      border-top: 1px solid var(--border);
      padding-top: 1.5rem;
    }
    .info-section .disclaimer {
      font-size: 0.75rem;
      color: var(--foreground-light);
      background: var(--background-alt);
      padding: 0.75rem 1rem;
      border-radius: 0.5rem;
      margin-bottom: 1.5rem;
      line-height: 1.6;
    }
    .info-section h3 {
      font-size: 1.125rem;
      font-weight: 600;
      margin: 1.5rem 0 0.75rem;
    }
    .info-section h4 {
      font-size: 1rem;
      font-weight: 600;
      margin: 1.25rem 0 0.5rem;
    }
    .info-section p {
      font-size: 0.875rem;
      line-height: 1.7;
      color: var(--foreground);
      margin: 0 0 1rem;
    }
    .info-section ul {
      margin: 0.5rem 0 1rem;
      padding-left: 1.25rem;
    }
    .info-section li {
      font-size: 0.875rem;
      line-height: 1.7;
      margin: 0.375rem 0;
    }
    .info-section .formula {
      background: var(--background-alt);
      padding: 1rem;
      border-radius: 0.5rem;
      font-family: 'Courier New', monospace;
      font-size: 0.8125rem;
      line-height: 1.8;
      margin: 0.75rem 0;
      overflow-x: auto;
    }
    .info-section .example {
      background: var(--background-alt);
      padding: 1rem;
      border-radius: 0.5rem;
      margin: 0.75rem 0;
      font-size: 0.875rem;
      line-height: 1.7;
    }

/* Sidebar Layout */
.calc-page-layout {
  display: grid;
  grid-template-columns: 250px 1fr;
  gap: 2rem;
  align-items: start;
}

@media (max-width: 1024px) {
  .calc-page-layout {
    grid-template-columns: 1fr;
    gap: 1.5rem;
  }
}

.calc-sidebar {
  border: 1px solid var(--border);
  border-radius: 0.5rem;
  padding: 1rem;
  background: #fff;
  position: sticky;
  top: 80px;
}

@media (max-width: 1024px) {
  .calc-sidebar {
    position: static;
    padding: 0.75rem;
  }
}
.sidebar-title {
  font-size: 0.875rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--foreground-light);
  font-weight: 700;
  margin: 0 0 1rem;
}


.sidebar-menu {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}


.sidebar-link {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.625rem 0.75rem;
  text-decoration: none;
  color: var(--foreground);
  border-radius: 0.375rem;
  font-size: 0.9375rem;
  transition: background 0.2s, color 0.2s;
}


.sidebar-link:hover {
  background: var(--background-alt);
}
.sidebar-link.active {
  background: var(--primary);
  color: #fff;
  font-weight: 500;
}
.sidebar-link .icon {
  font-size: 1.125rem;
}

@media (max-width: 480px) { .results-grid { grid-template-columns: 1fr; } }
.calc-card { min-width: 0; }
.calc-content { min-width: 0; }




/* Sidebar Accordion Mobile */
.sidebar-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1rem;
}
.sidebar-title { margin-bottom: 0 !important; }
.sidebar-toggle-btn {
  display: none;
  background: var(--background-alt);
  border: 1px solid var(--border);
  padding: 0.375rem 0.75rem;
  border-radius: 0.375rem;
  font-size: 0.8125rem;
  font-weight: 500;
  cursor: pointer;
  color: var(--foreground);
  align-items: center;
  gap: 0.375rem;
}

@media (max-width: 1024px) {
  .sidebar-toggle-btn { display: flex; }
  .sidebar-menu-wrapper {
    display: none;
  }
  .sidebar-menu-wrapper.open {
    display: block;
    margin-top: 1rem;
    padding-top: 1rem;
    border-top: 1px solid var(--border);
  }
}



/* FAQ Section Redesign */
.faq-wrap { margin-top: 1rem; padding-top: 0; }
.faq-section h2 {
  font-size: 1.5rem;
  margin-bottom: 1.5rem;
  color: var(--foreground);
  font-weight: 700;
}
.faq-item {
  margin-bottom: 1rem;
}
.faq-item details {
  background: var(--background-alt);
  border: 1px solid var(--border);
  border-radius: 0.5rem;
  overflow: hidden;
  transition: all 0.2s ease;
}
.faq-item details[open] {
  background: #fff;
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
}
.faq-item summary {
  padding: 1.25rem 1.5rem;
  font-weight: 600;
  cursor: pointer;
  list-style: none;
  display: flex;
  justify-content: space-between;
  align-items: center;
  color: var(--foreground);
  font-size: 1rem;
}
.faq-item summary::-webkit-details-marker {
  display: none;
}
.faq-item summary::after {
  content: '▼';
  font-size: 0.875rem;
  color: var(--foreground-light);
  transition: transform 0.3s ease;
}
.faq-item details[open] summary::after {
  transform: rotate(180deg);
  color: var(--primary);
}
.faq-item .faq-answer {
  padding: 0 1.5rem 1.5rem 1.5rem;
  font-size: 0.9375rem;
  color: var(--foreground-light);
  line-height: 1.7;
}