/* ============================================================
   ตัวแปลงหน่วยสากล — style.css
   Theme: Mountain / Mist / Forest — Glassmorphism
   COMPLETE VERSION — All sections styled
   ============================================================ */

/* ── CSS Variables ── */
:root {
  --bg-morning:   linear-gradient(160deg, #b3cde0 0%, #d4e8b5 50%, #f5f0e8 100%);
  --bg-day:       linear-gradient(160deg, #74b9d4 0%, #a8d8a8 50%, #e8f5e9 100%);
  --bg-evening:   linear-gradient(160deg, #d4956a 0%, #b07bab 50%, #3d4c7d 100%);
  --bg-night:     linear-gradient(160deg, #0d1b2a 0%, #1b3050 50%, #0f2540 100%);

  --glass-bg:     rgba(255,255,255,0.12);
  --glass-border: rgba(255,255,255,0.28);
  --glass-shadow: rgba(0,0,0,0.25);

  --text-primary:   #ffffff;
  --text-secondary: rgba(255,255,255,0.75);
  --text-muted:     rgba(255,255,255,0.50);

  --accent-green:  #5ecf8a;
  --accent-blue:   #4db8e8;
  --accent-warm:   #f0c060;
  --accent-red:    #e85d5d;

  --font-display: 'Kanit', sans-serif;
  --font-body:    'Sarabun', sans-serif;

  --radius-lg: 24px;
  --radius-md: 14px;
  --radius-sm: 8px;

  --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-fast: 0.15s ease;

  --max-width: 900px;
}

/* ── Reset ── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font-body);
  color: var(--text-primary);
  min-height: 100vh;
  overflow-x: hidden;
  background: #1a3040;
  line-height: 1.7;
}

/* ── Background Layers ── */
.bg-layer {
  position: fixed; inset: 0; z-index: 0;
  background: var(--bg-day);
  transition: background 2s ease;
}
.bg-layer.morning { background: var(--bg-morning); }
.bg-layer.day     { background: var(--bg-day); }
.bg-layer.evening { background: var(--bg-evening); }
.bg-layer.night   { background: var(--bg-night); }

/* SVG mountain silhouette via pseudo element */
.bg-layer::after {
  content: '';
  position: absolute; bottom: 0; left: 0; right: 0;
  height: 50vh;
  background: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 1440 400' preserveAspectRatio='none'%3E%3Cpath fill='rgba(0,30,20,0.35)' d='M0,400 L0,260 L120,180 L240,220 L360,100 L480,170 L560,60 L640,130 L720,40 L800,110 L900,30 L980,120 L1080,50 L1160,140 L1280,80 L1360,160 L1440,120 L1440,400Z'/%3E%3Cpath fill='rgba(0,40,25,0.25)' d='M0,400 L0,320 L180,260 L300,300 L440,200 L560,250 L680,170 L800,220 L920,160 L1060,230 L1200,170 L1320,240 L1440,200 L1440,400Z'/%3E%3C/svg%3E") center bottom / cover no-repeat;
}

.bg-overlay {
  position: fixed; inset: 0; z-index: 1;
  background: radial-gradient(ellipse at 30% 40%, rgba(100,200,120,0.12) 0%, transparent 60%),
              radial-gradient(ellipse at 80% 20%, rgba(70,150,220,0.10) 0%, transparent 55%);
  pointer-events: none;
}

.bg-fog {
  position: fixed; inset: 0; z-index: 2;
  background: linear-gradient(to bottom, transparent 30%, rgba(255,255,255,0.06) 60%, rgba(255,255,255,0.12) 100%);
  pointer-events: none;
  animation: fogDrift 18s ease-in-out infinite alternate;
}
@keyframes fogDrift {
  from { opacity: 0.6; transform: translateX(-10px); }
  to   { opacity: 1;   transform: translateX(10px); }
}

/* Floating particles */
.particles { position: fixed; inset: 0; z-index: 2; pointer-events: none; overflow: hidden; }
.particle {
  position: absolute;
  border-radius: 50%;
  background: rgba(255,255,255,0.35);
  animation: floatUp linear infinite;
}
@keyframes floatUp {
  0%   { transform: translateY(100vh) scale(0.8); opacity: 0; }
  10%  { opacity: 1; }
  90%  { opacity: 0.6; }
  100% { transform: translateY(-10vh) scale(1.1); opacity: 0; }
}

/* ── Layout wrapper ── */
.site-nav, .site-header, .main-content, .site-footer {
  position: relative; z-index: 10;
}

/* ================================================================
   NAVIGATION
   ================================================================ */
.site-nav {
  position: fixed; top: 0; left: 0; right: 0;
  z-index: 1000;
  padding: 0 5vw;
  background: rgba(10, 25, 40, 0.6);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid rgba(255,255,255,0.08);
  transition: var(--transition);
}
.site-nav.scrolled {
  background: rgba(10, 25, 40, 0.92);
  box-shadow: 0 4px 30px rgba(0,0,0,0.25);
  border-bottom-color: rgba(255,255,255,0.12);
}
.nav-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  display: flex;
  align-items: center;
  height: 60px;
}
.nav-logo {
  display: flex; align-items: center; gap: 8px;
  text-decoration: none; color: var(--text-primary);
  font-family: var(--font-display);
  font-weight: 700; font-size: 1.15rem;
  flex-shrink: 0;
}
.nav-logo-icon {
  font-size: 1.5rem;
  color: var(--accent-green);
  text-shadow: 0 0 16px rgba(94,207,138,0.5);
}
.nav-logo-text {
  background: linear-gradient(90deg, #fff, var(--accent-green));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.nav-links {
  display: flex; align-items: center; gap: 4px;
  margin-left: auto;
}
.nav-link {
  text-decoration: none;
  color: var(--text-secondary);
  font-family: var(--font-body);
  font-size: 0.88rem;
  padding: 8px 14px;
  border-radius: var(--radius-sm);
  transition: var(--transition-fast);
  white-space: nowrap;
}
.nav-link:hover {
  color: #fff;
  background: rgba(255,255,255,0.08);
}
.nav-link.active {
  color: var(--accent-green);
  background: rgba(94,207,138,0.1);
}

/* Language toggle */
.lang-toggle {
  background: rgba(255,255,255,0.08);
  border: 1px solid rgba(255,255,255,0.2);
  border-radius: 50px;
  padding: 6px 14px;
  font-family: var(--font-display);
  font-size: 0.8rem; font-weight: 600;
  color: var(--accent-warm);
  cursor: pointer;
  transition: var(--transition);
  margin-left: 8px;
  white-space: nowrap;
}
.lang-toggle:hover {
  background: rgba(240,192,96,0.15);
  border-color: var(--accent-warm);
}

/* Hamburger (mobile) */
.nav-toggle {
  display: none;
  background: none; border: none;
  cursor: pointer;
  padding: 8px;
  margin-left: auto;
  flex-direction: column; gap: 5px;
  align-items: center; justify-content: center;
  width: 40px; height: 40px;
}
.nav-toggle span {
  display: block; width: 22px; height: 2px;
  background: var(--text-primary);
  border-radius: 2px;
  transition: var(--transition);
}
.nav-toggle.open span:nth-child(1) {
  transform: rotate(45deg) translate(5px, 5px);
}
.nav-toggle.open span:nth-child(2) { opacity: 0; }
.nav-toggle.open span:nth-child(3) {
  transform: rotate(-45deg) translate(5px, -5px);
}

@media (max-width: 768px) {
  .nav-toggle { display: flex; }
  .nav-links {
    display: none;
    position: absolute;
    top: 60px; left: 0; right: 0;
    background: rgba(10, 25, 40, 0.95);
    backdrop-filter: blur(20px);
    flex-direction: column;
    padding: 16px;
    gap: 4px;
    border-bottom: 1px solid rgba(255,255,255,0.1);
    animation: navSlide 0.3s ease;
  }
  .nav-links.open { display: flex; }
  .nav-link { padding: 12px 16px; font-size: 1rem; }
  .lang-toggle { margin: 8px 0 0 0; width: 100%; text-align: center; padding: 12px; }
  @keyframes navSlide {
    from { opacity: 0; transform: translateY(-10px); }
    to   { opacity: 1; transform: translateY(0); }
  }
}

/* ── HEADER ── */
.site-header {
  padding: 88px 5vw 20px; /* account for fixed nav height */
  background: rgba(0,0,0,0.08);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(255,255,255,0.12);
}
.header-inner {
  max-width: var(--max-width); margin: 0 auto;
  display: flex; align-items: center; gap: 16px;
}
.logo-mark {
  font-size: 2.2rem; line-height: 1;
  color: var(--accent-green);
  text-shadow: 0 0 20px rgba(94,207,138,0.6);
  animation: pulse 3s ease-in-out infinite;
}
@keyframes pulse {
  0%, 100% { text-shadow: 0 0 20px rgba(94,207,138,0.6); }
  50%       { text-shadow: 0 0 40px rgba(94,207,138,1); }
}
.header-text { flex: 1; }
.site-title {
  font-family: var(--font-display);
  font-size: clamp(1.5rem, 4vw, 2.4rem);
  font-weight: 700;
  letter-spacing: 0.02em;
  background: linear-gradient(90deg, #fff 0%, var(--accent-green) 60%, var(--accent-blue) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.site-desc {
  font-size: 0.88rem; color: var(--text-secondary);
  margin-top: 2px; font-weight: 300;
}
.time-badge {
  font-family: var(--font-display); font-size: 1.1rem; font-weight: 600;
  background: var(--glass-bg); border: 1px solid var(--glass-border);
  padding: 6px 14px; border-radius: 50px; backdrop-filter: blur(8px);
  color: var(--accent-green); letter-spacing: 0.08em;
  white-space: nowrap;
}

/* ── MAIN CONTENT ── */
.main-content {
  max-width: 860px; margin: 0 auto;
  padding: 36px 5vw 60px;
  display: flex; flex-direction: column; gap: 28px;
}

/* ── Glassmorphism Card ── */
.glass {
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-lg);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  box-shadow: 0 8px 40px var(--glass-shadow), inset 0 1px 0 rgba(255,255,255,0.15);
}

/* ── SEARCH ── */
.search-wrap {
  position: relative;
  background: rgba(255,255,255,0.10);
  border: 1px solid rgba(255,255,255,0.22);
  border-radius: 50px;
  display: flex; align-items: center;
  padding: 0 20px;
  backdrop-filter: blur(16px);
  transition: var(--transition);
}
.search-wrap:focus-within {
  border-color: var(--accent-green);
  box-shadow: 0 0 0 3px rgba(94,207,138,0.2);
}
.search-icon { font-size: 1.1rem; margin-right: 10px; opacity: 0.7; }
.search-input {
  flex: 1; background: none; border: none; outline: none;
  color: var(--text-primary); font-family: var(--font-body);
  font-size: 1rem; padding: 14px 0;
}
.search-input::placeholder { color: var(--text-muted); }

.search-suggestions {
  position: absolute; top: calc(100% + 8px); left: 0; right: 0;
  background: rgba(10,30,20,0.85);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  backdrop-filter: blur(20px);
  overflow: hidden;
  z-index: 100;
  display: none;
}
.search-suggestions.active { display: block; }
.sugg-item {
  padding: 10px 18px; cursor: pointer;
  font-size: 0.92rem; color: var(--text-secondary);
  transition: var(--transition-fast);
  border-bottom: 1px solid rgba(255,255,255,0.05);
}
.sugg-item:last-child { border-bottom: none; }
.sugg-item:hover { background: rgba(94,207,138,0.15); color: #fff; }
.sugg-item strong { color: var(--accent-green); }

/* ── CONVERTER CARD ── */
.converter-card {
  padding: 36px 32px 32px;
  transition: var(--transition);
}
.converter-card:hover {
  box-shadow: 0 12px 60px rgba(0,0,0,0.35), inset 0 1px 0 rgba(255,255,255,0.2);
}

/* Field label */
.field-label {
  display: block;
  font-family: var(--font-display);
  font-size: 0.78rem; font-weight: 500;
  letter-spacing: 0.08em; text-transform: uppercase;
  color: var(--text-secondary); margin-bottom: 8px;
}

/* Field group */
.field-group { margin-bottom: 22px; }

/* Select wrapper */
.select-wrap { position: relative; }
.glass-select {
  width: 100%; appearance: none;
  background: rgba(255,255,255,0.07);
  border: 1px solid rgba(255,255,255,0.18);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-family: var(--font-body); font-size: 1rem;
  padding: 13px 42px 13px 16px;
  cursor: pointer;
  transition: var(--transition);
  outline: none;
}
.glass-select:focus {
  border-color: var(--accent-blue);
  box-shadow: 0 0 0 3px rgba(77,184,232,0.2);
}
.glass-select option { background: #1a3040; color: #fff; }
.select-arrow {
  position: absolute; right: 14px; top: 50%;
  transform: translateY(-50%);
  pointer-events: none; color: var(--text-secondary); font-size: 0.9rem;
}

/* Number input */
.glass-input {
  width: 100%; background: rgba(255,255,255,0.07);
  border: 1px solid rgba(255,255,255,0.18);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-family: var(--font-display); font-size: 1.4rem; font-weight: 500;
  padding: 13px 16px;
  outline: none; transition: var(--transition);
}
.glass-input:focus {
  border-color: var(--accent-green);
  box-shadow: 0 0 0 3px rgba(94,207,138,0.2);
}
.glass-input::placeholder { color: var(--text-muted); font-weight: 300; }

/* Converter row */
.converter-row {
  display: grid;
  grid-template-columns: 1fr 1fr auto 1fr;
  align-items: end;
  gap: 16px;
  margin-bottom: 22px;
}
.input-col { grid-column: 1; }
.unit-col  { }

/* Swap button */
.swap-btn {
  width: 48px; height: 48px;
  background: rgba(94,207,138,0.15);
  border: 1px solid rgba(94,207,138,0.4);
  border-radius: 50%;
  color: var(--accent-green);
  font-size: 1.3rem; cursor: pointer;
  transition: var(--transition);
  display: flex; align-items: center; justify-content: center;
  align-self: flex-end; margin-bottom: 1px;
}
.swap-btn:hover {
  background: rgba(94,207,138,0.3);
  transform: rotate(180deg) scale(1.1);
  box-shadow: 0 0 20px rgba(94,207,138,0.4);
}

/* Button row */
.btn-row {
  display: flex; gap: 12px; margin-bottom: 24px;
}
.btn {
  flex: 1; padding: 14px 20px;
  border: none; border-radius: var(--radius-md);
  font-family: var(--font-display); font-size: 1rem; font-weight: 600;
  cursor: pointer; transition: var(--transition);
  letter-spacing: 0.04em;
}
.btn-primary {
  background: linear-gradient(135deg, var(--accent-green) 0%, #3aaa6a 100%);
  color: #0d2018;
  box-shadow: 0 4px 20px rgba(94,207,138,0.4);
}
.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 30px rgba(94,207,138,0.6);
}
.btn-primary:active { transform: translateY(0); }

.btn-secondary {
  background: rgba(255,255,255,0.08);
  border: 1px solid rgba(255,255,255,0.2);
  color: var(--text-secondary);
}
.btn-secondary:hover {
  background: rgba(255,255,255,0.14);
  color: #fff;
}

/* ── RESULT PANEL ── */
.result-panel {
  background: rgba(0,0,0,0.15);
  border: 1px solid rgba(255,255,255,0.10);
  border-radius: var(--radius-md);
  min-height: 90px;
  display: flex; align-items: center; justify-content: center;
  padding: 22px 24px;
  transition: var(--transition);
}
.result-panel.has-result {
  background: rgba(94,207,138,0.06);
  border-color: rgba(94,207,138,0.25);
}
.result-placeholder {
  color: var(--text-muted); font-size: 0.92rem; text-align: center;
}
.result-main { width: 100%; text-align: center; }
.result-eq {
  font-family: var(--font-display);
  font-size: clamp(1.4rem, 4vw, 2rem);
  font-weight: 600;
  color: #fff;
  line-height: 1.3;
  animation: resultPop 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}
@keyframes resultPop {
  0%   { opacity: 0; transform: scale(0.85) translateY(10px); }
  100% { opacity: 1; transform: scale(1) translateY(0); }
}
.result-detail {
  font-size: 0.82rem; color: var(--text-muted);
  margin-top: 6px; font-style: italic;
}
.result-highlight { color: var(--accent-green); }
.result-highlight2 { color: var(--accent-blue); }

/* ── CATEGORY PILLS ── */
.cat-pills {
  display: flex; flex-wrap: wrap; gap: 10px;
  justify-content: center;
}
.cat-pill {
  padding: 8px 18px;
  background: rgba(255,255,255,0.08);
  border: 1px solid rgba(255,255,255,0.16);
  border-radius: 50px;
  font-family: var(--font-body); font-size: 0.85rem;
  color: var(--text-secondary);
  cursor: pointer; transition: var(--transition);
  white-space: nowrap;
}
.cat-pill:hover, .cat-pill.active {
  background: rgba(94,207,138,0.2);
  border-color: var(--accent-green);
  color: #fff;
  transform: translateY(-2px);
}

/* ================================================================
   EDUCATIONAL CONTENT SECTION
   ================================================================ */
.edu-section {
  padding: 36px 32px;
}
.edu-header {
  text-align: center;
  margin-bottom: 28px;
}
.edu-title {
  font-family: var(--font-display);
  font-size: 1.4rem;
  font-weight: 600;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  margin-bottom: 8px;
}
.edu-icon { font-size: 1.6rem; }
.edu-subtitle {
  font-size: 0.9rem;
  color: var(--text-secondary);
  max-width: 500px;
  margin: 0 auto;
}

/* Education Grid */
.edu-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 18px;
  margin-bottom: 24px;
}
@media (max-width: 680px) {
  .edu-grid { grid-template-columns: 1fr; }
}

/* Education Card */
.edu-card {
  background: rgba(255,255,255,0.06);
  border: 1px solid rgba(255,255,255,0.12);
  border-radius: var(--radius-md);
  padding: 20px;
  transition: var(--transition);
}
.edu-card:hover {
  background: rgba(255,255,255,0.09);
  border-color: rgba(255,255,255,0.2);
  transform: translateY(-2px);
}
.edu-card-highlight {
  background: rgba(240,192,96,0.08);
  border-color: rgba(240,192,96,0.2);
}
.edu-card-highlight:hover {
  background: rgba(240,192,96,0.12);
  border-color: rgba(240,192,96,0.3);
}
.edu-card-header {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 12px;
}
.edu-card-header h3 {
  font-family: var(--font-display);
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-primary);
}
.edu-card-icon { font-size: 1.3rem; }
.edu-card-body {
  font-size: 0.88rem;
  color: var(--text-secondary);
  line-height: 1.7;
}
.edu-card-body p { margin-bottom: 8px; }
.edu-card-body p:last-child { margin-bottom: 0; }
.edu-card-body code,
.edu-formula {
  display: inline-block;
  background: rgba(94,207,138,0.12);
  border: 1px solid rgba(94,207,138,0.25);
  border-radius: 6px;
  padding: 3px 10px;
  font-family: 'Courier New', monospace;
  font-size: 0.85rem;
  color: var(--accent-green);
  margin: 4px 2px;
}
.edu-card-body ul {
  padding-left: 18px;
  margin: 8px 0;
}
.edu-card-body li {
  margin-bottom: 4px;
}

/* Reference Table */
.edu-table-wrap {
  margin-top: 20px;
  background: rgba(0,0,0,0.12);
  border-radius: var(--radius-md);
  padding: 20px;
  border: 1px solid rgba(255,255,255,0.08);
}
.edu-table-title {
  font-family: var(--font-display);
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 14px;
}
.edu-table-scroll {
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}
.edu-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.85rem;
}
.edu-table th {
  background: rgba(94,207,138,0.12);
  color: var(--accent-green);
  font-family: var(--font-display);
  font-weight: 600;
  text-align: left;
  padding: 10px 14px;
  white-space: nowrap;
  border-bottom: 2px solid rgba(94,207,138,0.2);
}
.edu-table td {
  padding: 8px 14px;
  color: var(--text-secondary);
  border-bottom: 1px solid rgba(255,255,255,0.06);
  white-space: nowrap;
}
.edu-table tr:hover td {
  background: rgba(255,255,255,0.04);
  color: var(--text-primary);
}

/* Real World Card */
.edu-realworld {
  background: rgba(77,184,232,0.06);
  border: 1px solid rgba(77,184,232,0.2);
  border-radius: var(--radius-md);
  padding: 20px;
  margin-top: 18px;
}
.edu-realworld:hover {
  background: rgba(77,184,232,0.1);
}
.edu-realworld .edu-card-body ul {
  list-style: none;
  padding: 0;
}
.edu-realworld .edu-card-body li {
  padding: 6px 0;
  border-bottom: 1px solid rgba(255,255,255,0.05);
}
.edu-realworld .edu-card-body li:last-child {
  border-bottom: none;
}

/* ================================================================
   FAQ SECTION
   ================================================================ */
.faq-section {
  padding: 36px 32px;
}
.faq-title {
  font-family: var(--font-display);
  font-size: 1.3rem;
  font-weight: 600;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 24px;
  justify-content: center;
}
.faq-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
}
.faq-item {
  background: rgba(255,255,255,0.05);
  border: 1px solid rgba(255,255,255,0.10);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: var(--transition);
}
.faq-item:hover {
  border-color: rgba(255,255,255,0.18);
}
.faq-item.open {
  border-color: rgba(94,207,138,0.3);
  background: rgba(94,207,138,0.04);
}
.faq-question {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 20px;
  cursor: pointer;
  font-family: var(--font-display);
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--text-primary);
  transition: var(--transition-fast);
  user-select: none;
}
.faq-question:hover {
  color: var(--accent-green);
}
.faq-arrow {
  font-size: 0.9rem;
  color: var(--text-muted);
  transition: transform 0.3s ease;
}
.faq-item.open .faq-arrow {
  transform: rotate(180deg);
  color: var(--accent-green);
}
.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.4s ease, padding 0.3s ease;
  padding: 0 20px;
}
.faq-item.open .faq-answer {
  max-height: 500px;
  padding: 0 20px 18px;
}
.faq-answer p {
  font-size: 0.88rem;
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: 8px;
}
.faq-answer p:last-child { margin-bottom: 0; }

/* ================================================================
   SEO CONTENT SECTION
   ================================================================ */
.seo-content {
  display: flex;
  flex-direction: column;
  gap: 24px;
}
.seo-block {
  padding: 32px;
}
.seo-block h2 {
  font-family: var(--font-display);
  font-size: 1.3rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 16px;
  text-align: center;
}
.seo-block > p {
  font-size: 0.92rem;
  color: var(--text-secondary);
  line-height: 1.8;
  text-align: center;
  max-width: 700px;
  margin: 0 auto 24px;
}

/* Feature Grid */
.seo-features {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
}
@media (max-width: 600px) {
  .seo-features { grid-template-columns: 1fr; }
}
.seo-feature {
  background: rgba(255,255,255,0.05);
  border: 1px solid rgba(255,255,255,0.10);
  border-radius: var(--radius-md);
  padding: 22px 20px;
  text-align: center;
  transition: var(--transition);
}
.seo-feature:hover {
  background: rgba(255,255,255,0.08);
  transform: translateY(-3px);
  border-color: rgba(255,255,255,0.2);
}
.seo-feature-icon {
  font-size: 2rem;
  display: block;
  margin-bottom: 10px;
}
.seo-feature h3 {
  font-family: var(--font-display);
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 8px;
}
.seo-feature p {
  font-size: 0.85rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* SEO Categories List */
.seo-categories {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 14px;
}
.seo-cat-card {
  background: rgba(255,255,255,0.05);
  border: 1px solid rgba(255,255,255,0.10);
  border-radius: var(--radius-md);
  padding: 16px 18px;
  display: flex;
  align-items: center;
  gap: 12px;
  transition: var(--transition);
  cursor: pointer;
}
.seo-cat-card:hover {
  background: rgba(94,207,138,0.1);
  border-color: rgba(94,207,138,0.3);
  transform: translateY(-2px);
}
.seo-cat-icon { font-size: 1.5rem; }
.seo-cat-info h4 {
  font-family: var(--font-display);
  font-size: 0.88rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 2px;
}
.seo-cat-info p {
  font-size: 0.75rem;
  color: var(--text-muted);
}

/* ── HISTORY ── */
.history-section {
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-lg);
  backdrop-filter: blur(20px);
  padding: 24px 28px;
}
.section-title {
  font-family: var(--font-display); font-size: 1rem; font-weight: 600;
  color: var(--text-secondary);
  display: flex; align-items: center; gap: 8px;
  margin-bottom: 16px;
}
.clear-hist-btn {
  margin-left: auto;
  background: none; border: 1px solid rgba(255,255,255,0.2);
  border-radius: 50px; padding: 4px 14px;
  font-family: var(--font-body); font-size: 0.78rem;
  color: var(--text-muted); cursor: pointer; transition: var(--transition-fast);
}
.clear-hist-btn:hover { color: #fff; border-color: rgba(255,255,255,0.5); }

.history-list { display: flex; flex-direction: column; gap: 8px; }
.hist-item {
  display: flex; align-items: center; justify-content: space-between;
  background: rgba(255,255,255,0.05); border-radius: var(--radius-sm);
  padding: 10px 14px; font-size: 0.88rem;
  border: 1px solid rgba(255,255,255,0.06);
  transition: var(--transition-fast); cursor: pointer;
  animation: fadeSlide 0.3s ease;
  flex-wrap: wrap; gap: 6px;
}
@keyframes fadeSlide {
  from { opacity: 0; transform: translateX(-10px); }
  to   { opacity: 1; transform: translateX(0); }
}
.hist-item:hover { background: rgba(255,255,255,0.09); }
.hist-item .hist-expr { color: var(--text-primary); flex: 1; }
.hist-item .hist-time { color: var(--text-muted); font-size: 0.75rem; }
.hist-item .hist-cat {
  font-size: 0.72rem; color: var(--accent-green);
  background: rgba(94,207,138,0.12); padding: 2px 8px;
  border-radius: 50px; font-family: var(--font-display);
}

/* ================================================================
   FOOTER
   ================================================================ */
.site-footer {
  position: relative; z-index: 10;
  padding: 36px 5vw 24px;
  border-top: 1px solid rgba(255,255,255,0.08);
  background: rgba(0,0,0,0.15);
  backdrop-filter: blur(10px);
}
.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  display: grid;
  grid-template-columns: auto 1fr auto;
  gap: 24px;
  align-items: start;
}
@media (max-width: 680px) {
  .footer-inner {
    grid-template-columns: 1fr;
    text-align: center;
  }
}
.footer-brand {
  display: flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-display);
  font-weight: 600;
  color: var(--text-primary);
}
.footer-logo {
  font-size: 1.4rem;
  color: var(--accent-green);
}
.footer-name {
  font-size: 0.95rem;
}
.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: 6px 16px;
  justify-content: center;
}
.footer-links a {
  text-decoration: none;
  color: var(--text-muted);
  font-size: 0.82rem;
  transition: var(--transition-fast);
}
.footer-links a:hover {
  color: var(--accent-green);
}
.footer-info {
  text-align: right;
  font-size: 0.78rem;
  color: var(--text-muted);
}
.footer-info p { margin-bottom: 4px; }
@media (max-width: 680px) {
  .footer-info { text-align: center; }
}

/* ── Fade-in animation ── */
.fade-in {
  opacity: 0; transform: translateY(20px);
  animation: fadeIn 0.7s ease forwards;
}
.fade-in:nth-child(1) { animation-delay: 0.05s; }
.fade-in:nth-child(2) { animation-delay: 0.15s; }
.fade-in:nth-child(3) { animation-delay: 0.25s; }
.fade-in:nth-child(4) { animation-delay: 0.35s; }
@keyframes fadeIn {
  to { opacity: 1; transform: translateY(0); }
}

/* ================================================================
   SUB-PAGE TEMPLATE STYLES
   (about, contact, terms, privacy, knowledge)
   ================================================================ */
.page-content {
  max-width: 860px;
  margin: 0 auto;
  padding: 36px 5vw 60px;
}
.page-hero {
  text-align: center;
  padding: 100px 5vw 40px;
  background: rgba(0,0,0,0.08);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(255,255,255,0.12);
}
.page-hero-icon {
  font-size: 3rem;
  display: block;
  margin-bottom: 12px;
  animation: pulse 3s ease-in-out infinite;
}
.page-hero h1 {
  font-family: var(--font-display);
  font-size: clamp(1.6rem, 4vw, 2.4rem);
  font-weight: 700;
  background: linear-gradient(90deg, #fff 0%, var(--accent-green) 60%, var(--accent-blue) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: 8px;
}
.page-hero p {
  font-size: 0.95rem;
  color: var(--text-secondary);
  max-width: 560px;
  margin: 0 auto;
}

/* Content blocks */
.content-section {
  margin-bottom: 32px;
}
.content-section h2 {
  font-family: var(--font-display);
  font-size: 1.3rem;
  font-weight: 600;
  color: var(--accent-green);
  margin-bottom: 14px;
  display: flex;
  align-items: center;
  gap: 8px;
}
.content-section h3 {
  font-family: var(--font-display);
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 10px;
  margin-top: 18px;
}
.content-section p {
  font-size: 0.92rem;
  color: var(--text-secondary);
  line-height: 1.8;
  margin-bottom: 12px;
}
.content-section ul, .content-section ol {
  padding-left: 24px;
  margin-bottom: 14px;
}
.content-section li {
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: 6px;
}
.content-section a {
  color: var(--accent-blue);
  text-decoration: underline;
  text-underline-offset: 3px;
  transition: var(--transition-fast);
}
.content-section a:hover {
  color: var(--accent-green);
}

/* Glass content card for sub-pages */
.content-card {
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-lg);
  backdrop-filter: blur(20px);
  padding: 32px;
  margin-bottom: 24px;
}

/* Contact Form */
.contact-form {
  display: flex;
  flex-direction: column;
  gap: 18px;
}
.form-group {
  display: flex;
  flex-direction: column;
  gap: 6px;
}
.form-group label {
  font-family: var(--font-display);
  font-size: 0.82rem;
  font-weight: 500;
  color: var(--text-secondary);
  letter-spacing: 0.04em;
  text-transform: uppercase;
}
.form-group input,
.form-group textarea {
  background: rgba(255,255,255,0.07);
  border: 1px solid rgba(255,255,255,0.18);
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  font-family: var(--font-body);
  font-size: 0.95rem;
  padding: 12px 16px;
  outline: none;
  transition: var(--transition);
  resize: vertical;
}
.form-group input:focus,
.form-group textarea:focus {
  border-color: var(--accent-green);
  box-shadow: 0 0 0 3px rgba(94,207,138,0.15);
}
.form-group textarea {
  min-height: 120px;
}
.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 18px;
}
@media (max-width: 500px) {
  .form-row { grid-template-columns: 1fr; }
}
.form-success {
  background: rgba(94,207,138,0.1);
  border: 1px solid rgba(94,207,138,0.3);
  border-radius: var(--radius-md);
  padding: 16px 20px;
  text-align: center;
  color: var(--accent-green);
  font-weight: 500;
  display: none;
}

/* Knowledge page specific */
.knowledge-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 18px;
  margin: 20px 0;
}
.knowledge-card {
  background: rgba(255,255,255,0.06);
  border: 1px solid rgba(255,255,255,0.12);
  border-radius: var(--radius-md);
  padding: 22px 20px;
  transition: var(--transition);
  text-decoration: none;
  display: block;
}
.knowledge-card:hover {
  background: rgba(94,207,138,0.1);
  border-color: rgba(94,207,138,0.3);
  transform: translateY(-4px);
  box-shadow: 0 8px 30px rgba(0,0,0,0.2);
}
.knowledge-card-icon {
  font-size: 2rem;
  margin-bottom: 10px;
  display: block;
}
.knowledge-card h3 {
  font-family: var(--font-display);
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-primary) !important;
  margin-bottom: 6px;
  margin-top: 0 !important;
}
.knowledge-card p {
  font-size: 0.82rem;
  color: var(--text-muted) !important;
  line-height: 1.5;
  margin-bottom: 0 !important;
}

/* Table of Contents */
.toc-list {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 8px;
  margin: 16px 0;
}
.toc-list a {
  display: block;
  padding: 10px 14px;
  background: rgba(255,255,255,0.04);
  border: 1px solid rgba(255,255,255,0.08);
  border-radius: var(--radius-sm);
  text-decoration: none;
  color: var(--text-secondary);
  font-size: 0.88rem;
  transition: var(--transition-fast);
}
.toc-list a:hover {
  background: rgba(94,207,138,0.1);
  color: var(--accent-green);
  border-color: rgba(94,207,138,0.2);
}

/* Info box highlight */
.info-box {
  background: rgba(77,184,232,0.08);
  border-left: 4px solid var(--accent-blue);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  padding: 16px 20px;
  margin: 16px 0;
}
.info-box p {
  color: var(--text-secondary) !important;
  margin-bottom: 0 !important;
}

.warning-box {
  background: rgba(240,192,96,0.08);
  border-left: 4px solid var(--accent-warm);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  padding: 16px 20px;
  margin: 16px 0;
}

/* Stats row */
.stats-row {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 16px;
  margin: 20px 0;
}
.stat-card {
  text-align: center;
  padding: 20px 14px;
  background: rgba(255,255,255,0.05);
  border: 1px solid rgba(255,255,255,0.10);
  border-radius: var(--radius-md);
}
.stat-number {
  font-family: var(--font-display);
  font-size: 1.8rem;
  font-weight: 700;
  color: var(--accent-green);
  display: block;
}
.stat-label {
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-top: 4px;
}

/* Last updated badge */
.last-updated {
  display: inline-block;
  background: rgba(255,255,255,0.06);
  border: 1px solid rgba(255,255,255,0.12);
  border-radius: 50px;
  padding: 6px 16px;
  font-size: 0.78rem;
  color: var(--text-muted);
  margin-top: 8px;
}

/* Cookie consent */
.cookie-banner {
  position: fixed;
  bottom: 0; left: 0; right: 0;
  z-index: 9999;
  background: rgba(10, 25, 40, 0.95);
  backdrop-filter: blur(20px);
  border-top: 1px solid rgba(255,255,255,0.12);
  padding: 16px 5vw;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  flex-wrap: wrap;
  animation: slideUp 0.5s ease;
}
@keyframes slideUp {
  from { transform: translateY(100%); }
  to   { transform: translateY(0); }
}
.cookie-banner p {
  font-size: 0.85rem;
  color: var(--text-secondary);
  max-width: 600px;
}
.cookie-banner a {
  color: var(--accent-blue);
  text-decoration: underline;
}
.cookie-accept {
  background: var(--accent-green);
  color: #0d2018;
  border: none;
  border-radius: 50px;
  padding: 8px 24px;
  font-family: var(--font-display);
  font-size: 0.85rem;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
  white-space: nowrap;
}
.cookie-accept:hover {
  transform: scale(1.05);
  box-shadow: 0 4px 16px rgba(94,207,138,0.4);
}

/* ── Responsive ── */
@media (max-width: 680px) {
  .converter-row {
    grid-template-columns: 1fr 1fr;
    grid-template-rows: auto auto auto;
  }
  .input-col { grid-column: 1 / -1; }
  .swap-btn { grid-row: 3; grid-column: 1 / -1; width: 100%; border-radius: var(--radius-md); height: 44px; }
  .converter-card { padding: 24px 18px 20px; }
  .btn-row { flex-direction: column; }
  .header-inner { flex-wrap: wrap; }
  .time-badge { font-size: 0.9rem; }
  .edu-section { padding: 24px 18px; }
  .faq-section { padding: 24px 18px; }
  .seo-block { padding: 24px 18px; }
  .content-card { padding: 24px 18px; }
}
@media (max-width: 400px) {
  .site-title { font-size: 1.3rem; }
  .converter-row { grid-template-columns: 1fr; }
  .swap-btn { display: none; }
}

/* Breadcrumb */
.breadcrumb {
  padding: 12px 0;
  font-size: 0.82rem;
  color: var(--text-muted);
}
.breadcrumb a {
  color: var(--text-secondary);
  text-decoration: none;
  transition: var(--transition-fast);
}
.breadcrumb a:hover { color: var(--accent-green); }
.breadcrumb span { margin: 0 6px; }

/* Scroll to top */
.scroll-top {
  position: fixed;
  bottom: 24px; right: 24px;
  width: 44px; height: 44px;
  background: rgba(94,207,138,0.2);
  border: 1px solid rgba(94,207,138,0.4);
  border-radius: 50%;
  color: var(--accent-green);
  font-size: 1.2rem;
  cursor: pointer;
  display: none;
  align-items: center;
  justify-content: center;
  z-index: 999;
  transition: var(--transition);
  backdrop-filter: blur(10px);
}
.scroll-top:hover {
  background: rgba(94,207,138,0.4);
  transform: translateY(-3px);
}
.scroll-top.visible {
  display: flex;
}