@charset "utf-8";
/* ═══════════════════════════════════════
   RESET & BASE
═══════════════════════════════════════ */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}
body {
  font-family: 'Segoe UI', Arial, sans-serif;
  background-color: #F8F3E7;
  color: #2F3437;
  font-size: 16px;
}
a {
  text-decoration: none;
  color: inherit;
}
/* ═══════════════════════════════════════
   BREADCRUMB
═══════════════════════════════════════ */
.breadcrumb {
  background-color: #e8e2d6;
  padding: 10px 24px;
  font-size: 0.85rem;
  color: #555;
  border-bottom: 1px solid #d5cfc5;
}
.breadcrumb a {
  color: #1D3557;
  font-weight: 600;
}
.breadcrumb a:hover {
  text-decoration: underline;
}
.bc-sep {
  margin: 0 6px;
  color: #aaa;
}
.bc-current {
  color: #2F3437;
  font-weight: 600;
}
/* ═══════════════════════════════════════
   PAGE WRAPPER / TITLE
═══════════════════════════════════════ */
.page-wrapper {
  max-width: 960px;
  margin: 0 auto;
  padding: 24px 20px 40px;
}
.page-title-block {
  background: linear-gradient(135deg, #1D3557 0%, #2a4d73 100%);
  color: #F8F3E7;
  border-radius: 8px;
  padding: 36px 32px;
  margin-bottom: 28px;
}
.page-title-label {
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: #F5B041;
  margin-bottom: 8px;
}
.page-title-main {
  font-size: 2rem;
  font-weight: 700;
  line-height: 1.2;
  margin-bottom: 12px;
}
.page-title-sub {
  font-size: 1rem;
  opacity: 0.85;
  line-height: 1.6;
  max-width: 680px;
}
/* ═══════════════════════════════════════
   QUICK NAV
═══════════════════════════════════════ */
.quick-nav-label {
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: #888;
  margin-bottom: 0.75rem;
}
.quick-nav-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(110px, 1fr));
  gap: 0.6rem;
  margin-bottom: 2.5rem;
}
.qnav-card {
  background: #ffffff;
  border: 1px solid #e0dbd2;
  border-radius: 8px;
  padding: 0.75rem 0.5rem;
  text-align: center;
  color: #1D3557;
  font-size: 0.78rem;
  font-weight: 600;
  cursor: pointer;
  transition: box-shadow 0.2s, border-color 0.2s, transform 0.15s;
  text-decoration: none;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.35rem;
}
.qnav-card:hover {
  border-color: #2a4d73;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
  transform: translateY(-2px);
}
.qnav-card.active {
  border-color: #2a4d73;
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.12);
  transform: translateY(-2px);
  background-color: #1D3557;
  color: #fff;
}
.qnav-card.active .qnav-icon {
  filter: brightness(1.3);
}
.qnav-icon {
  font-size: 1.7rem;
  line-height: 1;
}
/* ═══════════════════════════════════════
   ARTICLE
═══════════════════════════════════════ */
.section-art-txt {
  margin: 0 0 28px 0;
  padding: 28px 28px 24px;
  background-color: #ffffff;
  border-radius: 8px;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.07);
}
.section-art-title {
  font-size: 1.2rem;
  font-weight: 700;
  color: #1D3557;
  border-left: 4px solid #E63946;
  padding-left: 12px;
  margin-bottom: 20px;
  line-height: 1.3;
}
.section-art-txt > p {
  font-size: 1rem;
  color: #2F3437;
  line-height: 1.6;
  margin-bottom: 16px;
}
.sub-heading {
  font-size: 1rem;
  font-weight: 700;
  color: #1D3557;
  margin: 22px 0 10px;
  padding-bottom: 4px;
  border-bottom: 1px solid #e0dbd2;
}
/* ═══════════════════════════════════════
   SPEED POLE GRID
═══════════════════════════════════════ */
.speed-pole-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 10px;
  margin: 16px 0;
}
.spg-cell {
  background: #EBF2FA;
  border-radius: 8px;
  padding: 14px 10px;
  text-align: center;
  border-top: 3px solid #1D3557;
}
.spg-poles {
  font-size: 0.68rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: #555;
  margin-bottom: 5px;
}
.spg-rpm {
  font-size: 1.4rem;
  font-weight: 900;
  color: #1D3557;
  margin-bottom: 2px;
}
.spg-note {
  font-size: 0.7rem;
  color: #888;
  line-height: 1.3;
}
/* ═══════════════════════════════════════
   TAPPED-WINDING DIAGRAM
═══════════════════════════════════════ */
.tapped-winding {
  background: #f9f7f2;
  border: 1px solid #e0dbd2;
  border-radius: 8px;
  padding: 16px;
  margin: 16px 0;
}
.tw-label {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: #555;
  margin-bottom: 12px;
}
.tw-body {
  display: flex;
  align-items: flex-end;
  gap: 0;
}
.tw-winding {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 4px;
}
.tw-seg {
  border-radius: 4px;
  padding: 6px 10px;
  font-size: 0.75rem;
  font-weight: 700;
  color: #fff;
  text-align: center;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.tw-seg--hi {
  background: #1D3557;
}
.tw-seg--med {
  background: #2a4d73;
}
.tw-seg--lo {
  background: #3d6899;
}
.tw-tap {
  font-size: 0.68rem;
  font-weight: 900;
  letter-spacing: 0.08em;
}
.tw-labels {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding-left: 10px;
  justify-content: flex-end;
}
.tw-speed-tag {
  height: 28px;
  display: flex;
  align-items: center;
  font-size: 0.75rem;
  font-weight: 700;
  color: #555;
  padding-left: 8px;
  border-left: 2px solid #e0dbd2;
}
.tw-speed-tag--hi {
  color: #1D3557;
  border-left-color: #1D3557;
}
.tw-speed-tag--med {
  color: #D4890A;
  border-left-color: #D4890A;
}
.tw-speed-tag--lo {
  color: #E63946;
  border-left-color: #E63946;
}
.tw-note {
  font-size: 0.8rem;
  color: #555;
  margin-top: 10px;
  line-height: 1.5;
}
/* ═══════════════════════════════════════
   SPEED METHOD CARDS
═══════════════════════════════════════ */
.method-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 14px;
  margin: 16px 0;
}
.method-card {
  border-radius: 8px;
  padding: 18px 16px;
  border: 1px solid #e0dbd2;
}
.method-card--blue {
  background: #EBF2FA;
  border-top: 3px solid #1D3557;
}
.method-card--gold {
  background: #FEF9EC;
  border-top: 3px solid #F5B041;
}
.method-card--green {
  background: #F0F7F4;
  border-top: 3px solid #2E7D52;
}
.method-card--purple {
  background: #F3EFF8;
  border-top: 3px solid #6A0DAD;
}
.method-icon {
  font-size: 1.6rem;
  margin-bottom: 8px;
}
.method-title {
  font-size: 0.9rem;
  font-weight: 700;
  color: #1D3557;
  margin-bottom: 6px;
}
.method-desc {
  font-size: 0.83rem;
  line-height: 1.55;
  color: #3a3f42;
}
.method-note {
  font-size: 0.78rem;
  color: #888;
  margin-top: 6px;
  font-style: italic;
}
/* ═══════════════════════════════════════
   VFD PARAMETER FLOW
═══════════════════════════════════════ */
.vfd-flow {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 10px;
  margin: 16px 0;
}
.vfd-param {
  background: #ECEFF1;
  border-radius: 6px;
  padding: 12px 12px 10px;
  border-left: 3px solid #455A64;
}
.vfd-param--nameplate {
  border-left-color: #1D3557;
  background: #EBF2FA;
}
.vfd-param--limits {
  border-left-color: #E63946;
  background: #FEF0F0;
}
.vfd-param--ramps {
  border-left-color: #D4890A;
  background: #FEF9EC;
}
.vfd-param--control {
  border-left-color: #2E7D52;
  background: #F0F7F4;
}
.vfd-param--feedback {
  border-left-color: #6A0DAD;
  background: #F3EFF8;
}
.vfd-step {
  font-size: 0.62rem;
  font-weight: 900;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: #888;
  margin-bottom: 4px;
}
.vfd-name {
  font-size: 0.84rem;
  font-weight: 700;
  color: #1D3557;
  margin-bottom: 5px;
}
.vfd-items {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 3px;
}
.vfd-items li {
  font-size: 0.78rem;
  color: #3a3f42;
  padding-left: 10px;
  position: relative;
  line-height: 1.4;
}
.vfd-items li::before {
  content: '–';
  position: absolute;
  left: 0;
  color: #aaa;
}
/* ═══════════════════════════════════════
   ROTATION TYPE CARDS
═══════════════════════════════════════ */
.rotation-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 14px;
  margin: 14px 0;
}
.rot-card {
  border-radius: 8px;
  padding: 16px;
  border: 1px solid #e0dbd2;
  position: relative;
}
.rot-card--rev {
  background: #F0F7F4;
  border-top: 3px solid #2E7D52;
}
.rot-card--fixed {
  background: #FEF0F0;
  border-top: 3px solid #E63946;
}
.rot-badge {
  position: absolute;
  top: -10px;
  right: 12px;
  font-size: 0.65rem;
  font-weight: 900;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  padding: 2px 8px;
  border-radius: 20px;
}
.rot-badge--yes {
  background: #2E7D52;
  color: #fff;
}
.rot-badge--no {
  background: #E63946;
  color: #fff;
}
.rot-icon {
  font-size: 1.6rem;
  margin-bottom: 8px;
}
.rot-title {
  font-size: 0.92rem;
  font-weight: 700;
  color: #1D3557;
  margin-bottom: 6px;
}
.rot-method {
  font-size: 0.82rem;
  font-weight: 600;
  color: #2F3437;
  margin-bottom: 4px;
}
.rot-desc {
  font-size: 0.8rem;
  line-height: 1.5;
  color: #3a3f42;
}
/* ═══════════════════════════════════════
   REVERSAL STEPS (three-phase)
═══════════════════════════════════════ */
.swap-visual {
  display: flex;
  align-items: center;
  gap: 12px;
  background: #f4f1e8;
  border: 1px solid #e0dbd2;
  border-radius: 8px;
  padding: 14px 16px;
  margin: 12px 0;
  flex-wrap: wrap;
  justify-content: center;
}
.swap-col {
  display: flex;
  flex-direction: column;
  gap: 6px;
  align-items: center;
}
.swap-col-label {
  font-size: 0.65rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: #888;
}
.swap-lead {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.78rem;
  font-weight: 900;
  color: #fff;
}
.swap-lead--t1 {
  background: #E63946;
}
.swap-lead--t2 {
  background: #1D3557;
}
.swap-lead--t3 {
  background: #2E7D52;
}
.swap-arrow {
  font-size: 1.4rem;
  color: #D4890A;
  flex-shrink: 0;
}
.swap-note {
  font-size: 0.82rem;
  color: #555;
  line-height: 1.5;
  flex: 1;
  min-width: 180px;
}
/* ═══════════════════════════════════════
   SHARED COMPONENTS (reg-block, callout, check-list, table, etc.)
═══════════════════════════════════════ */
.reg-block {
  border: 1px solid #e0dbd2;
  border-radius: 8px;
  overflow: hidden;
  margin-bottom: 20px;
}
.reg-block-header {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 14px 18px;
}
.reg-hdr--blue {
  background-color: #1D3557;
  color: #F8F3E7;
}
.reg-hdr--gold {
  background-color: #D4890A;
  color: #fff;
}
.reg-hdr--green {
  background-color: #2E7D52;
  color: #F8F3E7;
}
.reg-hdr--slate {
  background-color: #455A64;
  color: #F8F3E7;
}
.reg-icon {
  font-size: 1.3rem;
  flex-shrink: 0;
}
.reg-block-header h4 {
  font-size: 1rem;
  font-weight: 700;
  flex: 1;
  line-height: 1.3;
}
.reg-block-body {
  padding: 18px 20px;
  background-color: #fdfcfa;
}
.reg-block-body p {
  font-size: 0.95rem;
  line-height: 1.6;
  color: #2F3437;
  margin-bottom: 12px;
}
.reg-block-body p:last-child {
  margin-bottom: 0;
}
.check-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 6px;
}
.check-list li {
  font-size: 0.95rem;
  color: #2F3437;
  padding-left: 24px;
  position: relative;
  line-height: 1.5;
}
.check-list li::before {
  content: '✓';
  position: absolute;
  left: 0;
  color: #2E7D52;
  font-weight: 700;
}
.callout {
  display: flex;
  gap: 14px;
  align-items: flex-start;
  border-radius: 8px;
  padding: 16px 18px;
  margin-top: 16px;
}
.callout--tip {
  background-color: #EBF2FA;
  border-left: 4px solid #1D3557;
}
.callout--warn {
  background-color: #FEF9EC;
  border-left: 4px solid #F5B041;
}
.callout--red {
  background-color: #FEF0F0;
  border-left: 4px solid #E63946;
}
.callout--green {
  background-color: #F0F7F4;
  border-left: 4px solid #2E7D52;
}
.callout-icon {
  font-size: 1.4rem;
  flex-shrink: 0;
}
.callout strong {
  display: block;
  font-size: 0.9rem;
  color: #1D3557;
  margin-bottom: 4px;
}
.callout p {
  font-size: 0.9rem;
  line-height: 1.55;
  color: #2F3437;
  margin: 0;
}
.data-table-wrap {
  overflow-x: auto;
  margin-bottom: 4px;
}
.styled-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.88rem;
}
.styled-table th {
  background-color: #1D3557;
  color: #F8F3E7;
  padding: 10px 12px;
  text-align: left;
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.04em;
}
.styled-table td {
  padding: 9px 12px;
  border-bottom: 1px solid #e8e2d6;
  color: #2F3437;
  vertical-align: top;
}
.styled-table tbody tr:nth-child(even) {
  background-color: #f9f7f2;
}
.styled-table tbody tr:hover {
  background-color: #EBF2FA;
}
.formula-box {
  background-color: #f4f1e8;
  border-left: 4px solid #1D3557;
  border-radius: 6px;
  padding: 14px 20px;
  margin: 14px 0;
}
.formula-box p {
  margin: 4px 0;
  color: #1D3557;
  font-size: 1rem;
  font-weight: 700;
}
.formula-note {
  font-size: 0.82rem !important;
  font-weight: 400 !important;
  color: #555 !important;
}

/* QUIZ NAV */
.quiz-nav-container {
  text-align: center;
  margin-bottom: 0.75rem;
}

.quiz-nav {
  display: flex;
  justify-content: center;
}

.quiz-nav-btn {
  display: inline-block;
  background-color: #E63946;
  color: #F8F3E7;
  text-decoration: none;
  padding: 0.85rem 1.4rem;
  border-radius: 0.5rem;
  font-weight: 600;
  transition: background-color 0.2s, transform 0.2s, box-shadow 0.2s;
  box-shadow: 0 4px 12px rgba(29, 53, 87, 0.18);
  border: 2px solid transparent;
}

.quiz-nav-btn:hover {
  background-color: #C92F3B;
  transform: translateY(-1px);
  box-shadow: 0 6px 14px rgba(29, 53, 87, 0.24);
}

.quiz-nav-btn:focus {
  outline: none;
  border-color: #F1C40F;
}

/* FOOTER NAV */
.main-footer-nav {
  background-color: #1D3557;
  display: flex;
  justify-content: center;
  gap: 12px;
  padding: 16px 24px;
  flex-wrap: wrap;
}
.main-footer-nav-btn {
  display: inline-block;
  background-color: #F5B041;
  color: #2F3437;
  font-weight: 700;
  font-size: 0.9rem;
  padding: 10px 24px;
  border-radius: 4px;
  transition: background-color 0.2s;
  text-decoration: none;
}
.main-footer-nav-btn:hover {
  background-color: #F8C471;
}
.site-footer {
  background-color: #2F3437;
  color: #F8F3E7;
  padding: 40px 24px 24px;
}
.footer-container {
  display: flex;
  align-items: flex-start;
  justify-content: center;
  color: #F1C40F;
  gap: 32px;
  max-width: 1200px;
  margin: 0 auto;
}
.footer-col {
  text-align: left;
  color: #F1C40F;
  margin: 0 50px;
}
.footer-col a {
  color: #F1C40F;
  text-decoration: underline;
  transition: opacity 0.2s;
}
.footer-col a:hover {
  opacity: 0.5;
}
.footer-col h3 {
  font-size: 1.05rem;
  color: #F1C40F;
  margin-bottom: 10px;
}
.footer-col p {
  font-size: 0.9rem;
  opacity: 0.8;
  line-height: 1.7;
}
.footer-credit {
  text-align: center;
  font-size: 0.8rem;
  opacity: 0.6;
  margin-top: 24px;
  padding-top: 16px;
  border-top: 1px solid rgba(255, 255, 255, 0.15);
  max-width: 1200px;
  margin-left: auto;
  margin-right: auto;
}
/* ═══════════════════════════════════════
   RESPONSIVE
═══════════════════════════════════════ */
@media (max-width: 768px) {
  .page-title-main {
    font-size: 1.5rem;
  }
  .page-title-block {
    padding: 24px 20px;
  }
  .section-art-txt {
    padding: 20px 16px;
  }
  .quick-nav-grid {
    grid-template-columns: repeat(3, 1fr);
  }
  .footer-container {
    flex-direction: column;
    gap: 20px;
  }
  .speed-pole-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .vfd-flow {
    grid-template-columns: repeat(2, 1fr);
  }
}
@media (max-width: 480px) {
  .quick-nav-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .speed-pole-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .swap-visual {
    flex-direction: column;
  }
}
.back-to-top {
  position: fixed;
  bottom: 28px;
  right: 24px;
  z-index: 999;
  padding: 10px 18px;
  font-size: 0.85rem;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.3s ease, transform 0.3s ease;
  transform: translateY(10px);
  border-radius: 4px;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
}
.back-to-top.visible {
  opacity: 1;
  pointer-events: auto;
  transform: translateY(0);
}
.section-art-txt[id] {
  scroll-margin-top: 80px;
}