/* ══════════════════════════════════════════════
   UNIT CONVERTER — style.css
   Dark-mode, glassmorphism, premium design
   ══════════════════════════════════════════════ */

/* ── Google Fonts ── */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800&family=Sarabun:wght@300;400;500;600;700&display=swap');

/* ── Design Tokens ── */
:root {
  --bg-primary:    #0D1117;
  --bg-secondary:  #161B22;
  --bg-card:       #1C2333;
  --bg-input:      #0D1117;
  --bg-hover:      #21262D;
  --border:        #30363D;
  --border-light:  #21262D;

  --text-primary:  #E6EDF3;
  --text-secondary:#8B949E;
  --text-muted:    #6E7681;

  /* Brand gradient */
  --grad-primary:  linear-gradient(135deg, #5B6EEA 0%, #9B59F6 50%, #E040FB 100%);
  --grad-warm:     linear-gradient(135deg, #FF6B35 0%, #F7C59F 100%);
  --grad-cool:     linear-gradient(135deg, #1FA2FF 0%, #12D8FA 50%, #A6FFCB 100%);
  --grad-green:    linear-gradient(135deg, #11998E 0%, #38EF7D 100%);

  --accent-blue:   #58A6FF;
  --accent-purple: #BC8CFF;
  --accent-orange: #FF7B54;
  --accent-green:  #3FB950;
  --accent-pink:   #E040FB;

  /* Category colors */
  --col-distance:  #58A6FF;
  --col-weight:    #3FB950;
  --col-temp:      #FF7B54;
  --col-area:      #BC8CFF;
  --col-volume:    #12D8FA;

  --radius-sm:  8px;
  --radius-md:  14px;
  --radius-lg:  20px;
  --radius-xl:  28px;

  --shadow-card: 0 4px 24px rgba(0,0,0,0.4);
  --shadow-glow: 0 0 40px rgba(91,110,234,0.15);

  --transition: 0.2s ease;
  --font-main:  'Inter', 'Sarabun', sans-serif;
}

/* ── Reset ── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font-main);
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
}

/* ── Container ── */
.container { max-width: 960px; margin: 0 auto; padding: 0 20px; }

/* ══════════════════════════════════════════════
   HEADER
   ══════════════════════════════════════════════ */
header {
  background: linear-gradient(180deg, #0D1117 0%, #111827 100%);
  border-bottom: 1px solid var(--border);
  padding: 28px 0 32px;
  text-align: center;
  position: relative;
  overflow: hidden;
}
header::before {
  content: '';
  position: absolute;
  top: -60px; left: 50%;
  transform: translateX(-50%);
  width: 600px; height: 300px;
  background: radial-gradient(ellipse, rgba(91,110,234,0.18) 0%, transparent 70%);
  pointer-events: none;
}

.logo-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: rgba(255,255,255,0.05);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 5px 14px;
  font-size: 13px;
  color: var(--text-secondary);
  margin-bottom: 16px;
  backdrop-filter: blur(6px);
}
.logo-icon { font-size: 16px; }

h1 {
  font-size: clamp(28px, 5vw, 44px);
  font-weight: 800;
  background: var(--grad-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  letter-spacing: -0.5px;
  margin-bottom: 8px;
}
.header-sub {
  color: var(--text-secondary);
  font-size: 14px;
  margin-bottom: 24px;
}

/* ── Search ── */
.search-wrap {
  position: relative;
  max-width: 520px;
  margin: 0 auto 8px;
}
.search-icon {
  position: absolute;
  left: 14px; top: 50%;
  transform: translateY(-50%);
  font-size: 16px;
  pointer-events: none;
}
.search-input {
  width: 100%;
  background: var(--bg-card);
  border: 1.5px solid var(--border);
  border-radius: 999px;
  padding: 12px 44px 12px 42px;
  font-family: var(--font-main);
  font-size: 14px;
  color: var(--text-primary);
  outline: none;
  transition: border-color var(--transition), box-shadow var(--transition);
}
.search-input:focus {
  border-color: #5B6EEA;
  box-shadow: 0 0 0 3px rgba(91,110,234,0.18);
}
.search-input::placeholder { color: var(--text-muted); }
.search-clear {
  position: absolute;
  right: 12px; top: 50%;
  transform: translateY(-50%);
  background: none;
  border: none;
  color: var(--text-muted);
  font-size: 14px;
  cursor: pointer;
  padding: 4px;
  opacity: 0;
  transition: opacity var(--transition);
}
.search-clear.visible { opacity: 1; }

.search-results {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  max-width: 520px;
  margin: 6px auto 0;
  overflow: hidden;
  display: none;
}
.search-results.open { display: block; }
.search-result-item {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 10px 16px;
  cursor: pointer;
  transition: background var(--transition);
  border-bottom: 1px solid var(--border-light);
}
.search-result-item:last-child { border-bottom: none; }
.search-result-item:hover { background: var(--bg-hover); }
.sri-unit { font-weight: 600; font-size: 14px; color: var(--text-primary); }
.sri-cat  { font-size: 12px; color: var(--text-muted); }
.sri-badge {
  margin-left: auto;
  font-size: 11px;
  padding: 2px 8px;
  border-radius: 999px;
  background: rgba(91,110,234,0.15);
  color: var(--accent-blue);
}

/* ══════════════════════════════════════════════
   MAIN
   ══════════════════════════════════════════════ */
main { padding: 32px 0 48px; }

/* ── Ad Slots ── */
.ad-slot {
  background: var(--bg-secondary);
  border: 1px dashed var(--border);
  border-radius: var(--radius-md);
  display: flex; align-items: center; justify-content: center;
  color: var(--text-muted);
  font-size: 12px;
  letter-spacing: 1px;
}
.ad-slot-top { height: 90px; margin-bottom: 28px; }
.ad-slot-mid { height: 250px; margin: 32px 0; }

/* ══════════════════════════════════════════════
   CATEGORY TABS
   ══════════════════════════════════════════════ */
.category-tabs {
  display: flex;
  gap: 8px;
  margin-bottom: 24px;
  flex-wrap: wrap;
}
.cat-tab {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
  padding: 10px 18px;
  background: var(--bg-card);
  border: 1.5px solid var(--border);
  border-radius: var(--radius-md);
  color: var(--text-secondary);
  font-family: var(--font-main);
  font-size: 13px;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition);
  flex: 1;
  min-width: 90px;
}
.cat-tab:hover {
  background: var(--bg-hover);
  color: var(--text-primary);
  border-color: #5B6EEA;
}
.cat-tab.active {
  background: linear-gradient(135deg, rgba(91,110,234,0.2) 0%, rgba(155,89,246,0.2) 100%);
  border-color: #5B6EEA;
  color: var(--text-primary);
  box-shadow: 0 0 16px rgba(91,110,234,0.2);
}
.cat-icon { font-size: 22px; }
.cat-label { font-size: 12px; }

/* ── Category specific active colors ── */
.cat-tab[data-cat="distance"].active { border-color: var(--col-distance); box-shadow: 0 0 16px rgba(88,166,255,0.2); background: rgba(88,166,255,0.1); }
.cat-tab[data-cat="weight"].active   { border-color: var(--col-weight);   box-shadow: 0 0 16px rgba(63,185,80,0.2);  background: rgba(63,185,80,0.1); }
.cat-tab[data-cat="temperature"].active { border-color: var(--col-temp); box-shadow: 0 0 16px rgba(255,123,84,0.2); background: rgba(255,123,84,0.1); }
.cat-tab[data-cat="area"].active     { border-color: var(--col-area);     box-shadow: 0 0 16px rgba(188,140,255,0.2); background: rgba(188,140,255,0.1); }
.cat-tab[data-cat="volume"].active   { border-color: var(--col-volume);   box-shadow: 0 0 16px rgba(18,216,250,0.2); background: rgba(18,216,250,0.1); }

/* ══════════════════════════════════════════════
   CONVERTER PANEL
   ══════════════════════════════════════════════ */
.converter-panel {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-xl);
  overflow: hidden;
  box-shadow: var(--shadow-card);
  margin-bottom: 28px;
}

.cat-panel { display: none; padding: 24px; }
.cat-panel.active { display: block; }

.panel-header { margin-bottom: 20px; }
.panel-title {
  font-size: 18px;
  font-weight: 700;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 4px;
}
.panel-icon { font-size: 20px; }
.panel-subtitle {
  font-size: 13px;
  color: var(--text-muted);
  padding-left: 28px;
}

/* ── Converter Grid ── */
.converter-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 12px;
}

/* ── Unit Input Card ── */
.unit-card {
  background: var(--bg-input);
  border: 1.5px solid var(--border);
  border-radius: var(--radius-md);
  padding: 14px 16px;
  transition: border-color var(--transition), box-shadow var(--transition), transform var(--transition);
  position: relative;
}
.unit-card:hover {
  border-color: rgba(91,110,234,0.4);
  transform: translateY(-1px);
}
.unit-card.focused {
  border-color: #5B6EEA;
  box-shadow: 0 0 0 3px rgba(91,110,234,0.15);
}
.unit-card.changed {
  animation: pulse-border 0.4s ease;
}
@keyframes pulse-border {
  0%   { box-shadow: 0 0 0 0 rgba(91,110,234,0.5); }
  100% { box-shadow: 0 0 0 6px rgba(91,110,234,0); }
}

/* Category-specific colors */
.cat-panel#panel-distance .unit-card.focused { border-color: var(--col-distance); box-shadow: 0 0 0 3px rgba(88,166,255,0.15); }
.cat-panel#panel-weight   .unit-card.focused { border-color: var(--col-weight);   box-shadow: 0 0 0 3px rgba(63,185,80,0.15); }
.cat-panel#panel-temperature .unit-card.focused { border-color: var(--col-temp); box-shadow: 0 0 0 3px rgba(255,123,84,0.15); }
.cat-panel#panel-area     .unit-card.focused { border-color: var(--col-area);     box-shadow: 0 0 0 3px rgba(188,140,255,0.15); }
.cat-panel#panel-volume   .unit-card.focused { border-color: var(--col-volume);   box-shadow: 0 0 0 3px rgba(18,216,250,0.15); }

.unit-label {
  font-size: 11px;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.8px;
  margin-bottom: 6px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.unit-name { font-size: 11px; color: var(--text-muted); }
.unit-copy-btn {
  background: none;
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  font-size: 12px;
  padding: 2px 4px;
  border-radius: 4px;
  transition: color var(--transition), background var(--transition);
  opacity: 0;
}
.unit-card:hover .unit-copy-btn { opacity: 1; }
.unit-copy-btn:hover { color: var(--text-primary); background: var(--bg-hover); }

.unit-input-wrap {
  display: flex;
  align-items: baseline;
  gap: 6px;
}
.unit-input {
  flex: 1;
  background: none;
  border: none;
  font-family: var(--font-main);
  font-size: 22px;
  font-weight: 700;
  color: var(--text-primary);
  width: 100%;
  min-width: 0;
  outline: none;
  padding: 0;
}
.unit-input::placeholder { color: var(--text-muted); font-weight: 400; font-size: 18px; }
/* Remove number spinners */
.unit-input::-webkit-outer-spin-button,
.unit-input::-webkit-inner-spin-button { -webkit-appearance: none; }
.unit-input[type=number] { -moz-appearance: textfield; }

.unit-symbol {
  font-size: 13px;
  color: var(--text-muted);
  white-space: nowrap;
  flex-shrink: 0;
}

/* ══════════════════════════════════════════════
   CARDS / SHARED
   ══════════════════════════════════════════════ */
.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-xl);
  padding: 24px;
  box-shadow: var(--shadow-card);
  margin-bottom: 24px;
}
.card-title {
  font-size: 15px;
  font-weight: 700;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 18px;
}
.icon {
  width: 30px; height: 30px;
  border-radius: 8px;
  display: flex; align-items: center; justify-content: center;
  font-size: 16px;
  flex-shrink: 0;
}
.icon-orange { background: rgba(255,123,84,0.15); }
.icon-purple { background: rgba(188,140,255,0.15); }
.icon-blue   { background: rgba(88,166,255,0.15); }
.icon-green  { background: rgba(63,185,80,0.15); }

/* ══════════════════════════════════════════════
   QUICK REFERENCE
   ══════════════════════════════════════════════ */
.quick-ref-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 10px;
}
.quick-ref-item {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 12px 14px;
  cursor: pointer;
  transition: all var(--transition);
}
.quick-ref-item:hover {
  background: var(--bg-hover);
  border-color: rgba(91,110,234,0.4);
  transform: translateY(-1px);
}
.qr-from { font-size: 16px; font-weight: 700; color: var(--text-primary); }
.qr-arrow { font-size: 12px; color: var(--text-muted); margin: 2px 0; }
.qr-to   { font-size: 13px; color: var(--accent-blue); font-weight: 500; }

/* ══════════════════════════════════════════════
   THAI LAND UNITS
   ══════════════════════════════════════════════ */
.thai-info-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(170px, 1fr));
  gap: 12px;
  margin-bottom: 24px;
}
.thai-info-item {
  background: linear-gradient(135deg, rgba(188,140,255,0.08) 0%, rgba(91,110,234,0.08) 100%);
  border: 1px solid rgba(188,140,255,0.2);
  border-radius: var(--radius-md);
  padding: 14px;
  text-align: center;
}
.thai-info-label { font-size: 13px; font-weight: 700; color: var(--accent-purple); margin-bottom: 4px; }
.thai-info-value { font-size: 15px; font-weight: 700; color: var(--text-primary); margin-bottom: 4px; }
.thai-info-sub   { font-size: 12px; color: var(--text-muted); }

.thai-calc-title {
  font-size: 14px;
  font-weight: 600;
  color: var(--text-secondary);
  margin-bottom: 12px;
  padding-top: 8px;
  border-top: 1px solid var(--border);
}
.thai-calc-row {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  gap: 12px;
  margin-bottom: 16px;
}
.thai-input-group { display: flex; flex-direction: column; gap: 6px; }
.thai-label {
  font-size: 12px;
  font-weight: 600;
  color: var(--text-muted);
  text-align: center;
}
.thai-input {
  background: var(--bg-input);
  border: 1.5px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 10px;
  font-family: var(--font-main);
  font-size: 20px;
  font-weight: 700;
  color: var(--text-primary);
  text-align: center;
  outline: none;
  transition: border-color var(--transition), box-shadow var(--transition);
}
.thai-input:focus {
  border-color: var(--accent-purple);
  box-shadow: 0 0 0 3px rgba(188,140,255,0.15);
}
.thai-input::-webkit-outer-spin-button,
.thai-input::-webkit-inner-spin-button { -webkit-appearance: none; }
.thai-input[type=number] { -moz-appearance: textfield; }

.thai-calc-results {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 8px;
}
.thai-result-row {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 10px 14px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.thai-result-label { font-size: 13px; color: var(--text-secondary); }
.thai-result-val   { font-size: 14px; font-weight: 700; color: var(--accent-purple); }

/* ══════════════════════════════════════════════
   FAQ
   ══════════════════════════════════════════════ */
.faq-list { display: flex; flex-direction: column; gap: 8px; }
.faq-item {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: border-color var(--transition);
}
.faq-item[open] { border-color: rgba(91,110,234,0.35); }
.faq-q {
  padding: 14px 18px;
  font-size: 14px;
  font-weight: 600;
  color: var(--text-primary);
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  gap: 8px;
  user-select: none;
}
.faq-q::before { content: '▶'; font-size: 10px; color: var(--text-muted); transition: transform 0.2s; }
.faq-item[open] .faq-q::before { transform: rotate(90deg); }
.faq-q::-webkit-details-marker { display: none; }
.faq-a {
  padding: 0 18px 14px;
  font-size: 13px;
  color: var(--text-secondary);
  line-height: 1.7;
  border-top: 1px solid var(--border-light);
  padding-top: 10px;
}

/* ══════════════════════════════════════════════
   TOAST
   ══════════════════════════════════════════════ */
.toast {
  position: fixed;
  bottom: 24px;
  left: 50%;
  transform: translateX(-50%) translateY(80px);
  background: var(--bg-hover);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 10px 22px;
  font-size: 13px;
  color: var(--text-primary);
  box-shadow: 0 8px 32px rgba(0,0,0,0.5);
  opacity: 0;
  transition: all 0.35s cubic-bezier(0.34,1.56,0.64,1);
  pointer-events: none;
  z-index: 9999;
  white-space: nowrap;
}
.toast.show {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

/* ══════════════════════════════════════════════
   FOOTER
   ══════════════════════════════════════════════ */
footer {
  background: var(--bg-secondary);
  border-top: 1px solid var(--border);
  padding: 24px 0;
  text-align: center;
  color: var(--text-muted);
  font-size: 13px;
}
.footer-links {
  display: flex;
  justify-content: center;
  gap: 20px;
  margin-top: 12px;
  flex-wrap: wrap;
}
.footer-links a {
  color: var(--text-muted);
  text-decoration: none;
  font-size: 12px;
  transition: color var(--transition);
}
.footer-links a:hover { color: var(--accent-blue); }

/* ══════════════════════════════════════════════
   RESPONSIVE
   ══════════════════════════════════════════════ */
@media (max-width: 600px) {
  .category-tabs { gap: 6px; }
  .cat-tab { padding: 8px 10px; min-width: 62px; font-size: 11px; }
  .cat-icon { font-size: 18px; }
  .converter-grid { grid-template-columns: 1fr 1fr; }
  .quick-ref-grid { grid-template-columns: 1fr 1fr; }
  .thai-info-grid { grid-template-columns: 1fr 1fr; }
  .thai-calc-results { grid-template-columns: 1fr; }
  .unit-input { font-size: 18px; }
}
@media (max-width: 400px) {
  .converter-grid { grid-template-columns: 1fr; }
  .thai-calc-row { grid-template-columns: 1fr 1fr 1fr; gap: 8px; }
}