/* ── Fonts ────────────────────────────────────────────────── */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500&family=JetBrains+Mono:wght@400;500&display=swap');

/* ── Reset ────────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

/* ── Base ─────────────────────────────────────────────────── */
html {
  scroll-behavior: smooth;
  background-color: var(--surface-canvas);
  color: var(--color-ink-black);
  font-family: var(--font-primary);
  font-size: var(--text-body-sm);
  line-height: var(--leading-body-sm);
  letter-spacing: var(--tracking-body-sm);
  font-weight: var(--font-weight-regular);
  -webkit-font-smoothing: antialiased;
}

body { overflow-x: hidden; }
a { color: inherit; text-decoration: none; }
ul, ol { padding-left: 1.4em; }
li { margin-bottom: 6px; }
strong { font-weight: var(--font-weight-medium); }

/* ── Nav ──────────────────────────────────────────────────── */
.bmi-nav {
  background-color: var(--surface-canvas);
  border-bottom: 1px solid var(--color-ink-black);
  height: 64px;
  position: sticky;
  top: 0;
  z-index: 100;
}

.bmi-nav-inner {
  max-width: var(--page-max-width);
  height: 100%;
  margin: 0 auto;
  padding: 0 var(--spacing-24);
  display: flex;
  align-items: center;
  gap: var(--spacing-24);
}

.logo {
  display: flex;
  align-items: center;
  gap: var(--spacing-12);
  color: var(--color-ink-black);
  flex-shrink: 0;
}

.logo-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  border: 1px solid var(--color-ink-black);
  border-radius: var(--radius-nav);
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: -0.02em;
}

.logo-text {
  font-size: var(--text-body-sm);
  font-weight: var(--font-weight-medium);
  letter-spacing: var(--tracking-body-sm);
}

.bmi-nav-links {
  display: flex;
  gap: var(--spacing-24);
  flex: 1;
  justify-content: center;
}

.bmi-nav-link {
  font-size: var(--text-body-sm);
  letter-spacing: var(--tracking-body-sm);
  color: var(--color-ash-gray);
  padding: 4px 0;
  border-bottom: 1px solid transparent;
  transition: color 0.15s ease, border-color 0.15s ease;
}

.bmi-nav-link:hover,
.bmi-nav-link.active {
  color: var(--color-ink-black);
  border-bottom-color: var(--color-ink-black);
}

.btn-back {
  flex-shrink: 0;
  font-size: var(--text-caption);
  letter-spacing: var(--tracking-caption);
  color: var(--color-ink-black);
  border: 1px solid var(--color-ink-black);
  border-radius: var(--radius-buttons);
  padding: 6px 14px;
  transition: background-color 0.15s ease, color 0.15s ease;
}

.btn-back:hover {
  background-color: var(--color-ink-black);
  color: var(--color-paper-white);
}

/* ── Page Hero ────────────────────────────────────────────── */
.page-hero {
  background-color: var(--surface-fog-card);
  border-bottom: 1px solid var(--color-ink-black);
  padding: var(--spacing-96) var(--spacing-24);
}

.page-hero-inner {
  max-width: var(--page-max-width);
  margin: 0 auto;
}

.page-hero-meta {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-6);
  margin-bottom: var(--spacing-24);
}

.meta-tag {
  display: inline-block;
  font-size: var(--text-caption);
  font-weight: var(--font-weight-medium);
  letter-spacing: 0.06em;
  color: var(--color-ink-black);
  border: 1px solid var(--color-ink-black);
  border-radius: var(--radius-buttons);
  padding: 4px 12px;
}

.page-hero-heading {
  font-size: var(--text-heading);
  font-weight: var(--font-weight-medium);
  line-height: var(--leading-heading);
  letter-spacing: var(--tracking-heading);
  color: var(--color-ink-black);
  margin-bottom: var(--spacing-12);
}

.page-hero-sub {
  font-size: var(--text-body-sm);
  letter-spacing: var(--tracking-body-sm);
  color: var(--color-ash-gray);
  max-width: 640px;
  line-height: var(--leading-body-sm);
}

/* ── Main Layout Grid ─────────────────────────────────────── */
.calc-main {
  padding: var(--section-gap) 0;
  background-color: var(--surface-canvas);
}

.uc-layout-container {
  max-width: var(--page-max-width);
  margin: 0 auto;
  padding: 0 var(--spacing-24);
  display: grid;
  grid-template-columns: 240px 1fr 1fr;
  gap: var(--spacing-24);
  align-items: start;
}

/* ── Sidebar (Category list) ──────────────────────────────── */
.uc-sidebar {
  border: 1px solid var(--color-ink-black);
  border-radius: var(--radius-cards);
  padding: var(--spacing-24) var(--spacing-12);
  background-color: var(--surface-canvas);
  display: flex;
  flex-direction: column;
  gap: var(--spacing-6);
  position: sticky;
  top: 88px;
}

.uc-sidebar-title {
  font-size: 11px;
  font-weight: var(--font-weight-medium);
  letter-spacing: 0.08em;
  color: var(--color-ink-black);
  text-transform: uppercase;
  margin-bottom: var(--spacing-12);
  padding-bottom: var(--spacing-6);
  border-bottom: 1px solid var(--color-ink-black);
}

.uc-cat-btn {
  display: flex;
  align-items: center;
  gap: var(--spacing-12);
  width: 100%;
  padding: 10px 12px;
  border-radius: var(--radius-buttons);
  background: none;
  border: 1px solid transparent;
  cursor: pointer;
  color: var(--color-ink-black);
  font-family: var(--font-primary);
  font-size: var(--text-caption);
  text-align: left;
  transition: all 0.15s ease;
}

.uc-cat-btn:hover {
  background-color: var(--surface-fog-card);
  border-color: var(--color-ink-black);
}

.uc-cat-btn.active {
  background-color: var(--color-highlighter-yellow);
  border-color: var(--color-ink-black);
  font-weight: var(--font-weight-medium);
}

/* ── Responsive Mobile Strip (Hidden on Desktop) ────────── */
.uc-cat-strip {
  display: none;
  background-color: var(--surface-canvas);
  border-bottom: 1px solid var(--color-ink-black);
  position: sticky;
  top: 64px;
  z-index: 90;
}

.uc-cat-strip-scroll {
  display: flex;
  gap: var(--spacing-8);
  overflow-x: auto;
  padding: var(--spacing-12) var(--spacing-24);
  scrollbar-width: none;
}

.uc-cat-strip-scroll::-webkit-scrollbar {
  display: none;
}

.uc-strip-chip {
  flex-shrink: 0;
  padding: 8px 16px;
  border-radius: 9999px;
  background-color: var(--surface-fog-card);
  border: 1px solid var(--color-ink-black);
  color: var(--color-ink-black);
  font-family: var(--font-primary);
  font-size: var(--text-caption);
  cursor: pointer;
  transition: all 0.15s ease;
}

.uc-strip-chip.active {
  background-color: var(--color-highlighter-yellow);
  font-weight: var(--font-weight-medium);
}

.btn-trigger-drawer {
  display: none;
}

/* ── Panels ───────────────────────────────────────────────── */
.uc-panel {
  border: 1px solid var(--color-ink-black);
  border-radius: var(--radius-cards);
  padding: var(--spacing-36);
  background-color: var(--surface-canvas);
}

.panel-label {
  font-size: var(--text-caption);
  font-weight: var(--font-weight-medium);
  letter-spacing: 0.07em;
  color: var(--color-ink-black);
  text-transform: uppercase;
  margin-bottom: var(--spacing-24);
  padding-bottom: var(--spacing-12);
  border-bottom: 1px solid var(--color-ink-black);
}

.uc-heading {
  font-size: var(--text-heading-sm);
  font-weight: var(--font-weight-medium);
  line-height: var(--leading-heading-sm);
  letter-spacing: var(--tracking-heading-sm);
  color: var(--color-ink-black);
  margin-bottom: var(--spacing-24);
  display: flex;
  align-items: center;
  gap: var(--spacing-12);
}

.field-group {
  margin-bottom: var(--spacing-24);
}

.field-label {
  display: block;
  font-size: var(--text-caption);
  font-weight: var(--font-weight-medium);
  letter-spacing: 0.06em;
  color: var(--color-ink-black);
  text-transform: uppercase;
  margin-bottom: var(--spacing-6);
}

/* ── Form Controls ────────────────────────────────────────── */
.uc-select {
  width: 100%;
  height: 42px;
  background-color: var(--surface-fog-card);
  border: 1px solid var(--color-ink-black);
  border-radius: var(--radius-inputs);
  padding: 0 var(--spacing-12);
  font-family: var(--font-primary);
  font-size: var(--text-body-sm);
  letter-spacing: var(--tracking-body-sm);
  color: var(--color-ink-black);
  outline: none;
  cursor: pointer;
  appearance: none;
  -webkit-appearance: none;
  background-image: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 20 20'%3e%3cpath stroke='%231a1a1a' stroke-linecap='round' stroke-linejoin='round' stroke-width='1.5' d='M6 8l4 4 4-4'/%3e%3c/svg%3e");
  background-repeat: no-repeat;
  background-position: right 12px center;
  background-size: 16px;
  transition: background-color 0.15s ease;
}

.uc-select:focus {
  background-color: var(--surface-canvas);
}

.uc-input-wrap {
  position: relative;
  display: flex;
  align-items: center;
}

.uc-input {
  width: 100%;
  height: 52px;
  background-color: var(--surface-fog-card);
  border: 1px solid var(--color-ink-black);
  border-radius: var(--radius-inputs);
  padding: 0 64px 0 var(--spacing-16);
  font-family: var(--font-mono);
  font-size: var(--text-heading-sm);
  font-weight: 500;
  color: var(--color-ink-black);
  transition: background-color 0.15s ease;
}

.uc-input:focus {
  outline: none;
  background-color: var(--surface-canvas);
}

.uc-unit-badge {
  position: absolute;
  right: var(--spacing-16);
  font-family: var(--font-mono);
  font-size: var(--text-caption);
  font-weight: 500;
  color: var(--color-ash-gray);
  pointer-events: none;
}

.uc-swap-row {
  display: flex;
  align-items: center;
  gap: var(--spacing-12);
  margin: var(--spacing-24) 0;
}

.uc-divider {
  flex: 1;
  height: 1px;
  background-color: var(--color-ink-black);
}

.uc-swap-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 42px;
  height: 42px;
  border-radius: 50%;
  background-color: var(--color-highlighter-yellow);
  border: 1px solid var(--color-ink-black);
  cursor: pointer;
  color: var(--color-ink-black);
  transition: transform 0.25s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.uc-swap-btn:hover {
  transform: rotate(180deg) scale(1.05);
}

.uc-result-wrap {
  position: relative;
  display: flex;
  align-items: center;
  height: 52px;
  background-color: var(--surface-fog-card);
  border: 1px solid var(--color-ink-black);
  border-radius: var(--radius-inputs);
  padding: 0 64px 0 var(--spacing-16);
}

.uc-result-value {
  font-family: var(--font-mono);
  font-size: var(--text-heading-sm);
  font-weight: 500;
  color: var(--color-ink-black);
  overflow-x: auto;
  white-space: nowrap;
  width: 100%;
}
.uc-result-value::-webkit-scrollbar {
  height: 2px;
}
.uc-result-value::-webkit-scrollbar-thumb {
  background-color: var(--color-ash-gray);
}

.uc-formula {
  margin-top: var(--spacing-24);
  padding: var(--spacing-12);
  background-color: var(--surface-fog-card);
  border: 1px solid var(--color-ink-black);
  border-radius: var(--radius-inputs);
  font-size: var(--text-caption);
  color: var(--color-ink-black);
  text-align: center;
  line-height: 1.5;
}

.uc-formula strong {
  font-family: var(--font-mono);
  font-weight: 500;
}

/* ── Comparison Table ─────────────────────────────────────── */
.uc-table-card {
  border: 1px solid var(--color-ink-black);
  border-radius: var(--radius-cards);
  padding: var(--spacing-36);
  background-color: var(--surface-canvas);
}

.uc-table-heading {
  font-size: var(--text-subheading);
  font-weight: var(--font-weight-medium);
  color: var(--color-ink-black);
  margin-bottom: var(--spacing-6);
}

.uc-table-sub {
  font-size: var(--text-caption);
  color: var(--color-ash-gray);
  margin-bottom: var(--spacing-24);
}

.uc-table-sub strong {
  color: var(--color-ink-black);
  font-weight: var(--font-weight-medium);
}

.uc-table-wrap {
  border: 1px solid var(--color-ink-black);
  border-radius: var(--radius-inputs);
  overflow: hidden;
}

.uc-table {
  width: 100%;
  border-collapse: collapse;
  font-size: var(--text-caption);
}

.uc-table th {
  background-color: var(--surface-fog-card);
  border-bottom: 1px solid var(--color-ink-black);
  padding: 12px var(--spacing-16);
  text-align: left;
  font-weight: var(--font-weight-medium);
  color: var(--color-ink-black);
  font-size: 11px;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.uc-table td {
  padding: 12px var(--spacing-16);
  border-bottom: 1px solid var(--color-fog-gray);
  color: var(--color-ink-black);
  transition: background-color 0.1s ease;
}

.uc-table tbody tr {
  cursor: pointer;
}

.uc-table tbody tr:last-child td {
  border-bottom: none;
}

.uc-table tbody tr:hover td {
  background-color: var(--surface-fog-card);
}

.uc-row--from td {
  background-color: rgba(26, 26, 26, 0.03);
}

.uc-row--to td {
  background-color: var(--surface-accent-fill);
}

.uc-val {
  font-family: var(--font-mono);
  text-align: right;
  font-variant-numeric: tabular-nums;
  font-weight: 500;
}

.uc-code {
  font-family: var(--font-mono);
  background-color: var(--surface-fog-card);
  padding: 2px 6px;
  border-radius: 4px;
  border: 1px solid var(--color-ink-black);
  font-size: 12px;
}

/* ── Mobile Drawer (Bottom Sheet) ────────────────────────── */
.uc-backdrop {
  display: none;
  position: fixed;
  inset: 0;
  background-color: rgba(0, 0, 0, 0.4);
  z-index: 1000;
}

.uc-drawer {
  display: none;
  position: fixed;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: var(--surface-canvas);
  border-top: 1px solid var(--color-ink-black);
  border-radius: var(--radius-cards) var(--radius-cards) 0 0;
  z-index: 1001;
  padding: var(--spacing-24);
  transform: translateY(100%);
  transition: transform 0.3s cubic-bezier(0.25, 0.46, 0.45, 0.94);
  max-height: 75vh;
  overflow-y: auto;
}

.uc-drawer.open {
  transform: translateY(0);
}

.uc-drawer-pill {
  width: 40px;
  height: 4px;
  background-color: var(--color-ash-gray);
  border-radius: 2px;
  margin: 0 auto var(--spacing-16);
  cursor: pointer;
}

.uc-drawer-heading {
  font-size: var(--text-caption);
  font-weight: var(--font-weight-medium);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-ink-black);
  margin-bottom: var(--spacing-16);
  border-bottom: 1px solid var(--color-ink-black);
  padding-bottom: var(--spacing-6);
}

.uc-drawer-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--spacing-8);
}

.uc-drawer-item {
  display: flex;
  align-items: center;
  gap: var(--spacing-8);
  padding: 10px;
  background-color: var(--surface-fog-card);
  border: 1px solid var(--color-ink-black);
  border-radius: var(--radius-inputs);
  color: var(--color-ink-black);
  font-family: var(--font-primary);
  font-size: var(--text-caption);
  cursor: pointer;
  text-align: left;
  transition: all 0.15s ease;
}

.uc-drawer-item.active {
  background-color: var(--color-highlighter-yellow);
  font-weight: var(--font-weight-medium);
}

/* ── SEO Section ──────────────────────────────────────────── */
.uc-seo {
  margin-top: var(--section-gap);
  border-top: 1px solid var(--color-ink-black);
  padding-top: var(--spacing-48);
  margin-bottom: var(--spacing-96);
  background-color: var(--surface-canvas);
}

.uc-seo-inner {
  max-width: var(--page-max-width);
  margin: 0 auto;
  padding: 0 var(--spacing-24);
}

.uc-seo h2 {
  font-size: var(--text-subheading);
  font-weight: var(--font-weight-medium);
  color: var(--color-ink-black);
  margin-bottom: var(--spacing-16);
}

.uc-seo p {
  font-size: var(--text-caption);
  line-height: var(--leading-caption);
  color: var(--color-ink-black);
  margin-bottom: var(--spacing-16);
}

.uc-seo strong {
  font-weight: var(--font-weight-medium);
}

/* ── Footer ───────────────────────────────────────────────── */
.bmi-footer {
  background-color: var(--surface-canvas);
  border-top: 1px solid var(--color-ink-black);
  padding: var(--spacing-48) 0;
  text-align: center;
}

.bmi-footer-inner {
  max-width: var(--page-max-width);
  margin: 0 auto;
  padding: 0 var(--spacing-24);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--spacing-16);
}

.footer-note {
  font-size: var(--text-caption);
  color: var(--color-ash-gray);
  max-width: 600px;
  line-height: var(--leading-caption);
}

.footer-copy {
  font-size: var(--text-caption);
  font-family: var(--font-mono);
  color: var(--color-ash-gray);
}

/* ── Responsive ───────────────────────────────────────────── */
@media (max-width: 1024px) {
  .uc-layout-container {
    grid-template-columns: 1fr 1fr;
  }
  .uc-sidebar {
    display: none;
  }
  .uc-cat-strip {
    display: block;
  }
  .btn-trigger-drawer {
    display: flex;
  }
}

/* Checkbox Hack Toggle Styles */
.nav-toggle-cb {
  display: none !important;
}

.nav-toggle-btn {
  display: none;
  cursor: pointer;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border: 1px solid var(--color-ink-black);
  border-radius: var(--radius-nav);
  color: var(--color-ink-black);
  z-index: 2001;
  transition: all 0.15s ease;
}

.nav-toggle-btn:hover {
  background-color: var(--surface-fog-card);
}

.nav-toggle-cb:checked ~ .nav-toggle-btn {
  background-color: var(--color-ink-black);
  color: var(--color-paper-white);
  border-color: var(--color-ink-black);
}

.nav-toggle-cb:checked ~ .nav-toggle-btn .menu-open-icon {
  display: none !important;
}

.nav-toggle-cb:checked ~ .nav-toggle-btn .menu-close-icon {
  display: block !important;
}

@media (max-width: 768px) {
  .nav-toggle-btn {
    display: flex;
    order: 3;
  }

  .bmi-nav {
    height: 64px !important;
  }

  .bmi-nav-inner {
    height: 100% !important;
    flex-direction: row !important;
    justify-content: space-between !important;
    align-items: center !important;
    padding: 0 var(--spacing-16) !important;
    gap: var(--spacing-12) !important;
    flex-wrap: nowrap !important;
  }

  .bmi-nav-links {
    position: fixed !important;
    top: 0 !important;
    right: -300px !important;
    width: 280px !important;
    height: 100vh !important;
    background-color: var(--surface-canvas) !important;
    border-left: 1px solid var(--color-ink-black) !important;
    flex-direction: column !important;
    justify-content: flex-start !important;
    align-items: stretch !important;
    padding: 80px 24px 24px 24px !important;
    gap: 8px !important;
    z-index: 2000 !important;
    transition: transform 0.35s cubic-bezier(0.16, 1, 0.3, 1) !important;
    box-shadow: -10px 0 30px rgba(0, 0, 0, 0.08) !important;
    margin: 0 !important;
  }

  .nav-toggle-cb:checked ~ .bmi-nav-links {
    transform: translateX(-300px) !important;
  }

  .bmi-nav-link {
    font-size: 15px !important;
    padding: 12px 16px !important;
    border-bottom: none !important;
    border-left: 3px solid transparent !important;
    width: 100% !important;
    display: block !important;
    color: var(--color-ash-gray) !important;
    transition: all 0.15s ease;
    text-align: left !important;
    white-space: normal !important;
  }

  .bmi-nav-link:hover,
  .bmi-nav-link.active {
    border-left-color: var(--color-ink-black) !important;
    background-color: var(--surface-fog-card) !important;
    color: var(--color-ink-black) !important;
  }

  .btn-back {
    font-size: 11px !important;
    padding: 4px 10px !important;
    white-space: nowrap;
    flex-shrink: 0;
  }

  .uc-layout-container {
    grid-template-columns: 1fr;
    gap: var(--spacing-48);
  }
  .page-hero {
    padding: var(--spacing-48) var(--spacing-24);
  }
  .uc-panel {
    padding: var(--spacing-24);
  }
  .uc-table-card {
    padding: var(--spacing-24);
  }
  .uc-table th, .uc-table td {
    padding: 10px var(--spacing-8);
  }
}