/* ===== Design tokens ===== */
.vd-page {
  --vd-ink:        #1d2733;
  --vd-muted:      #667381;
  --vd-line:       #d8e0e8;
  --vd-bg:         #f0f4f8;
  --vd-panel:      #ffffff;
  --vd-primary:    #0f72b8;
  --vd-primary-dk: #09598f;
  --vd-good:       #287d55;
  --vd-warn:       #a45b00;
  --vd-danger:     #b83434;
  --vd-radius:     10px;
  --vd-shadow:     0 2px 12px rgba(29,39,51,0.09);

  min-height: 100vh;
  background: var(--vd-bg);
  color: var(--vd-ink);
  font-family: system-ui, -apple-system, "Segoe UI", sans-serif;
  line-height: 1.65;
  color-scheme: light;
}

.vd-page *, .vd-page *::before, .vd-page *::after { box-sizing: border-box; }
.vd-page [hidden] { display: none !important; }
.vd-page input, .vd-page select, .vd-page button { font: inherit; }

/* ===== Layout ===== */
.vd-tool {
  max-width: 1080px;
  margin: 0 auto;
  padding: 20px 16px 40px;
}

/* ===== Breadcrumb ===== */
.vd-breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px;
  margin-bottom: 14px;
  font-size: 0.87rem;
  font-weight: 700;
  color: var(--vd-muted);
}
.vd-breadcrumb a { color: var(--vd-primary-dk); text-decoration: none; }
.vd-breadcrumb a:hover { text-decoration: underline; }

/* ===== Header ===== */
.vd-header {
  margin-bottom: 20px;
  padding-bottom: 14px;
  border-bottom: 3px solid var(--vd-primary);
}
.vd-eyebrow {
  margin: 0 0 4px;
  color: var(--vd-primary-dk);
  font-size: 0.87rem;
  font-weight: 900;
}
.vd-header h1 {
  margin: 0 0 6px;
  font-size: clamp(1.65rem, 2.8vw, 2.2rem);
  line-height: 1.2;
}
.vd-lead {
  margin: 0;
  color: var(--vd-muted);
  font-size: 0.97rem;
  font-weight: 700;
}
.vd-noscript {
  padding: 12px 14px;
  border: 1px solid #f0b8b8;
  border-radius: var(--vd-radius);
  background: #fff0f0;
  color: var(--vd-danger);
  font-weight: 700;
  margin-bottom: 16px;
}

/* ===== Tabs ===== */
.vd-tabs {
  display: flex;
  gap: 8px;
  margin-bottom: 12px;
  flex-wrap: wrap;
}
.vd-tab {
  flex: 1 1 0;
  min-width: 100px;
  min-height: 44px;
  padding: 8px 14px;
  border: 1.5px solid var(--vd-line);
  border-radius: var(--vd-radius);
  background: var(--vd-panel);
  color: var(--vd-ink);
  font-weight: 800;
  cursor: pointer;
  transition: border-color 0.15s, background 0.15s, color 0.15s;
}
.vd-tab:hover, .vd-tab:focus-visible {
  border-color: var(--vd-primary);
  outline: none;
  box-shadow: 0 0 0 3px rgba(15,114,184,0.15);
}
.vd-tab[aria-selected="true"] {
  border-color: var(--vd-primary);
  background: var(--vd-primary);
  color: #fff;
}

/* ===== Workspace (2-col on desktop) ===== */
.vd-workspace {
  display: grid;
  grid-template-columns: 300px 1fr;
  gap: 12px;
  align-items: start;
}

/* ===== Left: form panels ===== */
.vd-left {
  background: var(--vd-panel);
  border: 1px solid var(--vd-line);
  border-radius: var(--vd-radius);
  box-shadow: var(--vd-shadow);
  overflow: hidden;
}
.vd-form-panel {
  padding: 20px;
}
.vd-field {
  display: grid;
  gap: 6px;
  margin-bottom: 14px;
}
.vd-field label {
  font-size: 0.92rem;
  font-weight: 800;
  color: var(--vd-ink);
}
.vd-optional {
  font-size: 0.78rem;
  font-weight: 700;
  color: var(--vd-muted);
  margin-left: 4px;
}
.vd-input-row {
  display: grid;
  grid-template-columns: 1fr auto;
  border: 1.5px solid var(--vd-line);
  border-radius: var(--vd-radius);
  background: #fff;
  overflow: hidden;
  transition: border-color 0.15s;
}
.vd-input-row:focus-within {
  border-color: var(--vd-primary);
  box-shadow: 0 0 0 3px rgba(15,114,184,0.12);
}
.vd-input-row input {
  min-height: 44px;
  border: 0;
  background: transparent;
  padding: 8px 10px;
  color: var(--vd-ink);
  font-weight: 700;
  width: 100%;
}
.vd-input-row input:focus { outline: none; }
.vd-unit,
.vd-input-row select {
  display: flex;
  align-items: center;
  min-width: 60px;
  border: 0;
  border-left: 1.5px solid var(--vd-line);
  background: #f6f8fa;
  padding: 0 10px;
  color: var(--vd-muted);
  font-weight: 800;
  font-size: 0.9rem;
}
.vd-input-row select:focus { outline: none; }
.vd-select {
  width: 100%;
  min-height: 44px;
  border: 1.5px solid var(--vd-line);
  border-radius: var(--vd-radius);
  background: #fff;
  padding: 8px 10px;
  font-weight: 700;
  color: var(--vd-ink);
}
.vd-select:focus-visible {
  border-color: var(--vd-primary);
  box-shadow: 0 0 0 3px rgba(15,114,184,0.12);
  outline: none;
}
.vd-radio-group {
  border: 0;
  padding: 0;
  margin: 0 0 14px;
  display: grid;
  gap: 8px;
}
.vd-radio-group legend {
  font-size: 0.92rem;
  font-weight: 800;
  margin-bottom: 6px;
}
.vd-radio-label {
  display: flex;
  align-items: flex-start;
  gap: 8px;
  padding: 9px 10px;
  border: 1.5px solid var(--vd-line);
  border-radius: var(--vd-radius);
  background: #fff;
  cursor: pointer;
  font-size: 0.91rem;
  font-weight: 700;
}
.vd-radio-label input { margin-top: 3px; accent-color: var(--vd-primary); }
.vd-reset {
  width: 100%;
  min-height: 40px;
  border: 1.5px solid var(--vd-line);
  border-radius: var(--vd-radius);
  background: #fff;
  color: var(--vd-muted);
  font-weight: 800;
  cursor: pointer;
  margin-top: 4px;
}
.vd-reset:hover { border-color: var(--vd-primary); color: var(--vd-primary); }

/* ===== Right: circuit + results ===== */
.vd-right {
  display: grid;
  gap: 12px;
}
.vd-circuit-box {
  background: var(--vd-panel);
  border: 1px solid var(--vd-line);
  border-radius: var(--vd-radius);
  box-shadow: var(--vd-shadow);
  padding: 12px;
  overflow: hidden;
}
.vd-svg {
  display: block;
  width: 100%;
  height: auto;
}
.vd-result-panel {
  background: var(--vd-panel);
  border: 1px solid var(--vd-line);
  border-radius: var(--vd-radius);
  box-shadow: var(--vd-shadow);
  padding: 18px;
  min-height: 80px;
}
.vd-e24-hint {
  margin: 0;
  color: var(--vd-muted);
  font-size: 0.91rem;
  font-weight: 700;
}

/* ===== Result cards ===== */
.vd-result-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 10px;
}
.vd-card {
  padding: 12px;
  border: 1px solid #c9dbe9;
  border-radius: var(--vd-radius);
  background: #fbfdff;
}
.vd-card-hidden {
  display: none;
}
.vd-card-label {
  display: block;
  font-size: 0.8rem;
  font-weight: 800;
  color: var(--vd-muted);
  margin-bottom: 4px;
}
.vd-card-value {
  display: block;
  font-size: 1.3rem;
  font-weight: 950;
  color: var(--vd-primary-dk);
  line-height: 1.2;
  overflow-wrap: anywhere;
}
.vd-card-sub {
  display: block;
  margin-top: 3px;
  font-size: 0.79rem;
  font-weight: 700;
  color: var(--vd-muted);
}

/* ===== Warnings ===== */
.vd-warn-list {
  display: grid;
  gap: 8px;
  margin-top: 10px;
}
.vd-warn-item {
  padding: 9px 12px;
  border: 1px solid #f0d08d;
  border-radius: var(--vd-radius);
  background: #fff8e6;
  color: #684500;
  font-size: 0.89rem;
  font-weight: 700;
}

/* ===== Error ===== */
.vd-error {
  padding: 10px 13px;
  border: 1px solid #f0b8b8;
  border-radius: var(--vd-radius);
  background: #fff0f0;
  color: var(--vd-danger);
  font-weight: 700;
  font-size: 0.9rem;
  margin-bottom: 12px;
}

/* ===== Copy ===== */
.vd-copy-row {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-top: 12px;
}
.vd-copy-btn {
  min-height: 38px;
  padding: 6px 14px;
  border: 1.5px solid var(--vd-line);
  border-radius: var(--vd-radius);
  background: #fff;
  color: var(--vd-ink);
  font-weight: 800;
  cursor: pointer;
}
.vd-copy-btn:hover { border-color: var(--vd-primary); color: var(--vd-primary); }
.vd-copy-status {
  font-size: 0.88rem;
  font-weight: 700;
  color: var(--vd-good);
}

/* ===== Reverse result ===== */
.vd-reverse-calc {
  margin-bottom: 12px;
}
.vd-calc-item {
  display: inline-flex;
  align-items: baseline;
  gap: 10px;
  padding: 10px 14px;
  background: #f0f7ff;
  border: 1px solid #c9dbe9;
  border-radius: var(--vd-radius);
}
.vd-calc-label { font-size: 0.88rem; font-weight: 800; color: var(--vd-muted); }
.vd-calc-value { font-size: 1.25rem; font-weight: 950; color: var(--vd-primary-dk); }

/* ===== E24 mini table (in reverse tab) ===== */
.vd-e24-mini-table {
  width: 100%;
  border-collapse: collapse;
  border: 1px solid var(--vd-line);
  border-radius: var(--vd-radius);
  overflow: hidden;
  margin-bottom: 14px;
  font-size: 0.9rem;
}
.vd-e24-mini-table th,
.vd-e24-mini-table td {
  padding: 8px 10px;
  text-align: left;
  border-bottom: 1px solid var(--vd-line);
}
.vd-e24-mini-table th {
  background: #eef6fb;
  color: var(--vd-primary-dk);
  font-size: 0.83rem;
  font-weight: 900;
  white-space: nowrap;
}
.vd-e24-mini-table tbody tr:last-child td { border-bottom: 0; }
.vd-e24-mini-table tbody tr:first-child { background: #f5fbff; }

/* ===== Form description ===== */
.vd-form-desc {
  margin: 0 0 16px;
  color: var(--vd-muted);
  font-size: 0.88rem;
  font-weight: 700;
}

/* ===== Result heading ===== */
.vd-result-heading {
  margin: 0 0 10px;
  font-size: 0.88rem;
  font-weight: 900;
  color: var(--vd-muted);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

/* ===== E24 candidates table (full-width) ===== */
.vd-candidates {
  margin-top: 12px;
  background: var(--vd-panel);
  border: 1px solid var(--vd-line);
  border-radius: var(--vd-radius);
  box-shadow: var(--vd-shadow);
  padding: 18px;
}
.vd-candidates-header {
  display: flex;
  align-items: baseline;
  gap: 14px;
  margin-bottom: 12px;
  flex-wrap: wrap;
}
.vd-candidates-header h2 {
  margin: 0;
  font-size: 1.1rem;
}
.vd-candidates-summary {
  margin: 0;
  color: var(--vd-muted);
  font-size: 0.88rem;
  font-weight: 700;
}
.vd-table-wrap {
  width: 100%;
  overflow-x: auto;
  border: 1px solid var(--vd-line);
  border-radius: var(--vd-radius);
}
.vd-table {
  width: 100%;
  min-width: 560px;
  border-collapse: collapse;
  background: #fff;
}
.vd-table th,
.vd-table td {
  padding: 9px 10px;
  text-align: left;
  vertical-align: top;
  border-bottom: 1px solid var(--vd-line);
}
.vd-table th {
  background: #eef6fb;
  color: var(--vd-primary-dk);
  font-size: 0.83rem;
  font-weight: 900;
  white-space: nowrap;
}
.vd-table tbody tr:last-child td { border-bottom: 0; }
.vd-table tbody tr.is-top { background: #eef6fb; }
.vd-table tbody tr.is-top td:first-child::before {
  content: '★ ';
  color: var(--vd-primary);
  font-size: 0.85em;
}
.vd-badge-ok   { display: inline-block; padding: 2px 8px; border-radius: 999px; background: #e8f5ee; color: var(--vd-good);   font-size: 0.8rem; font-weight: 800; }
.vd-badge-warn { display: inline-block; padding: 2px 8px; border-radius: 999px; background: #fff8e6; color: var(--vd-warn);   font-size: 0.8rem; font-weight: 800; }

/* ===== Notes ===== */
.vd-notes {
  margin-top: 16px;
  background: var(--vd-panel);
  border: 1px solid var(--vd-line);
  border-radius: var(--vd-radius);
  box-shadow: var(--vd-shadow);
  padding: 18px;
}
.vd-note-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
}
.vd-note-grid article {
  padding: 13px;
  border: 1px solid var(--vd-line);
  border-radius: var(--vd-radius);
  background: #fbfdff;
}
.vd-note-grid h3 { margin: 0 0 5px; font-size: 0.95rem; }
.vd-note-grid p  { margin: 0; font-size: 0.88rem; color: var(--vd-muted); font-weight: 700; }

/* ===== Explanation (SEO) ===== */
.vd-explain {
  margin-top: 16px;
  background: var(--vd-panel);
  border: 1px solid var(--vd-line);
  border-radius: var(--vd-radius);
  box-shadow: var(--vd-shadow);
  padding: 22px;
  display: grid;
  gap: 18px;
}
.vd-explain article { margin: 0; }
.vd-explain h2 {
  margin: 0 0 8px;
  font-size: 1.12rem;
  line-height: 1.35;
  color: var(--vd-primary-dk);
}
.vd-explain p {
  margin: 0;
  font-size: 0.92rem;
  color: var(--vd-ink);
}
.vd-explain ul {
  margin: 0;
  padding-left: 1.2em;
  display: grid;
  gap: 6px;
}
.vd-explain li {
  font-size: 0.92rem;
  color: var(--vd-ink);
}
.vd-explain strong { color: var(--vd-primary-dk); }

/* ===== FAQ ===== */
.vd-faq {
  margin-top: 16px;
  background: var(--vd-panel);
  border: 1px solid var(--vd-line);
  border-radius: var(--vd-radius);
  box-shadow: var(--vd-shadow);
  padding: 22px;
}
.vd-faq > h2 {
  margin: 0 0 14px;
  font-size: 1.12rem;
  color: var(--vd-primary-dk);
}
.vd-faq-item {
  border: 1px solid var(--vd-line);
  border-radius: var(--vd-radius);
  background: #fbfdff;
  margin-bottom: 10px;
  overflow: hidden;
}
.vd-faq-item:last-child { margin-bottom: 0; }
.vd-faq-item summary {
  padding: 13px 44px 13px 16px;
  position: relative;
  cursor: pointer;
  font-weight: 800;
  font-size: 0.94rem;
  color: var(--vd-ink);
  list-style: none;
}
.vd-faq-item summary::-webkit-details-marker { display: none; }
.vd-faq-item summary::after {
  content: '+';
  position: absolute;
  right: 16px;
  top: 50%;
  transform: translateY(-50%);
  font-size: 1.3rem;
  font-weight: 900;
  color: var(--vd-primary);
  line-height: 1;
}
.vd-faq-item[open] summary::after { content: '−'; }
.vd-faq-item summary:hover { color: var(--vd-primary); }
.vd-faq-item summary:focus-visible {
  outline: none;
  box-shadow: 0 0 0 3px rgba(15,114,184,0.15);
  border-radius: var(--vd-radius);
}
.vd-faq-body {
  padding: 0 16px 14px;
}
.vd-faq-body p {
  margin: 0;
  font-size: 0.9rem;
  color: var(--vd-muted);
  font-weight: 700;
}

/* ===== Related ===== */
.vd-related {
  margin-top: 14px;
  background: var(--vd-panel);
  border: 1px solid var(--vd-line);
  border-radius: var(--vd-radius);
  box-shadow: var(--vd-shadow);
  padding: 18px;
}
.vd-related h2 { margin: 0 0 12px; font-size: 1.1rem; }
.vd-related-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
}
.vd-related-grid a {
  display: grid;
  gap: 3px;
  padding: 13px;
  border: 1px solid var(--vd-line);
  border-radius: var(--vd-radius);
  background: #fbfdff;
  color: var(--vd-ink);
  text-decoration: none;
}
.vd-related-grid a:hover { border-color: var(--vd-primary); box-shadow: 0 0 0 3px rgba(15,114,184,0.12); }
.vd-related-grid strong { color: var(--vd-primary-dk); font-size: 0.93rem; line-height: 1.35; }
.vd-related-grid span   { color: var(--vd-muted); font-size: 0.84rem; font-weight: 700; }

/* ===== Footer ===== */
.vd-footer {
  margin-top: 18px;
  text-align: center;
  color: var(--vd-muted);
  font-size: 0.88rem;
  font-weight: 800;
}
.vd-footer a { color: var(--vd-primary-dk); text-decoration: none; }
.vd-footer a:hover { text-decoration: underline; }

/* ===== Responsive ===== */
@media (max-width: 820px) {
  .vd-workspace       { grid-template-columns: 1fr; }
  .vd-note-grid       { grid-template-columns: 1fr; }
  .vd-related-grid    { grid-template-columns: 1fr; }
}
@media (max-width: 520px) {
  .vd-tabs            { flex-direction: column; }
  .vd-tab             { flex: none; }
  .vd-result-grid     { grid-template-columns: 1fr; }
  .vd-tool            { padding-inline: 12px; }
}