/* ============================================
   CHEMCALC – GLOBAL STYLES
   Dark Mode Glassmorphism Design
   ============================================ */

:root {
  --bg: #060a14;
  --bg2: #0d1220;
  --bg3: #111827;
  --glass: rgba(255, 255, 255, 0.04);
  --glass2: rgba(255, 255, 255, 0.08);
  --border: rgba(255, 255, 255, 0.10);
  --border2: rgba(255, 255, 255, 0.16);
  --accent: #00e5ff;
  --accent2: #7c3aed;
  --accent3: #10b981;
  --danger: #ef4444;
  --warn: #f59e0b;
  --text: #f1f5f9;
  --text2: #94a3b8;
  --text3: #64748b;
  --radius: 16px;
  --radius-sm: 10px;
  --shadow: 0 8px 32px rgba(0,0,0,0.5);
  --shadow-glow: 0 0 40px rgba(0,229,255,0.15);
  --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

html { scroll-behavior: smooth; font-size: 16px; }

body {
  font-family: 'Inter', system-ui, sans-serif;
  background: var(--bg);
  color: var(--text);
  overflow-x: hidden;
  line-height: 1.6;
}

a { color: inherit; text-decoration: none; }
img { max-width: 100%; }

/* ---- UTILITIES ---- */
.container { max-width: 1200px; margin: 0 auto; padding: 0 24px; }
.accent { color: var(--accent); }

/* ============================================
   NAVBAR
   ============================================ */
.navbar {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  background: rgba(6, 10, 20, 0.85);
  backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border);
}
.nav-inner {
  max-width: 1200px; margin: 0 auto; padding: 0 24px;
  display: flex; align-items: center; gap: 32px; height: 64px;
}
.nav-logo {
  display: flex; align-items: center; gap: 12px;
  font-size: 1.35rem; font-weight: 800; flex-shrink: 0;
  transition: transform var(--transition);
}
.nav-logo:hover { transform: translateY(-1px); }
.nav-logo .logo-icon { 
  height: 32px; width: auto; 
  display: block;
  filter: drop-shadow(0 0 8px rgba(0,229,255,0.15));
  transition: all var(--transition);
}
.nav-logo:hover .logo-icon {
  filter: drop-shadow(0 0 12px rgba(0,229,255,0.4));
  transform: rotate(-5deg) scale(1.05);
}
.nav-links {
  display: flex; gap: 24px; list-style: none; margin-left: 8px;
}
.nav-links a {
  color: var(--text2); font-size: 0.9rem; font-weight: 500;
  transition: color var(--transition);
}
.nav-links a:hover { color: var(--accent); }
.nav-search-mini {
  margin-left: auto; position: relative;
}
.nav-search-mini input {
  background: var(--glass2); border: 1px solid var(--border);
  border-radius: 24px; padding: 8px 18px;
  color: var(--text); font-size: 0.85rem; width: 240px;
  outline: none; transition: border-color var(--transition);
}
.nav-search-mini input:focus { border-color: var(--accent); }
.nav-search-results {
  position: absolute; top: calc(100% + 8px); right: 0;
  background: var(--bg2); border: 1px solid var(--border2);
  border-radius: var(--radius-sm); width: 280px;
  box-shadow: var(--shadow); display: none;
  overflow: hidden; z-index: 200;
}
.nav-search-results.open { display: block; }
.search-result-item {
  padding: 10px 16px; display: flex; align-items: center; gap: 10px;
  cursor: pointer; transition: background var(--transition);
  font-size: 0.85rem;
}
.search-result-item:hover { background: var(--glass2); }
.search-result-item .sri-icon { font-size: 1.1rem; }

/* ============================================
   HERO SECTION
   ============================================ */
.hero {
  position: relative; min-height: 100vh;
  display: flex; align-items: center; justify-content: space-between;
  padding: 100px 24px 60px;
  max-width: 1200px; margin: 0 auto; gap: 60px;
  overflow: hidden;
}
.hero-bg {
  position: fixed; inset: 0; pointer-events: none; z-index: -1;
}
.hero-orb {
  position: absolute; border-radius: 50%;
  filter: blur(80px); opacity: 0.35;
}
.orb1 {
  width: 500px; height: 500px; top: -100px; left: -200px;
  background: radial-gradient(circle, #7c3aed, transparent 70%);
  animation: orbFloat 8s ease-in-out infinite;
}
.orb2 {
  width: 400px; height: 400px; top: 200px; right: -100px;
  background: radial-gradient(circle, #00e5ff, transparent 70%);
  animation: orbFloat 10s ease-in-out infinite reverse;
}
.orb3 {
  width: 300px; height: 300px; bottom: -50px; left: 40%;
  background: radial-gradient(circle, #10b981, transparent 70%);
  animation: orbFloat 12s ease-in-out infinite 3s;
}
@keyframes orbFloat {
  0%, 100% { transform: translateY(0) scale(1); }
  50% { transform: translateY(-30px) scale(1.05); }
}

#particleCanvas { position: absolute; inset: 0; width: 100%; height: 100%; }

.hero-content { flex: 1; max-width: 600px; }
.hero-badge {
  display: inline-flex; align-items: center; gap: 6px;
  background: rgba(0, 229, 255, 0.1); border: 1px solid rgba(0, 229, 255, 0.3);
  color: var(--accent); padding: 6px 16px; border-radius: 24px;
  font-size: 0.8rem; font-weight: 600; margin-bottom: 20px;
  animation: fadeSlideUp 0.6s ease both;
}
.hero-title {
  font-size: clamp(2.2rem, 5vw, 3.8rem); font-weight: 900;
  line-height: 1.1; margin-bottom: 20px;
  animation: fadeSlideUp 0.6s ease 0.1s both;
}
.hero-gradient {
  background: linear-gradient(135deg, var(--accent), var(--accent2));
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  background-clip: text;
}
.hero-subtitle {
  font-size: 1.1rem; color: var(--text2); margin-bottom: 36px;
  animation: fadeSlideUp 0.6s ease 0.2s both;
}

.hero-search { position: relative; margin-bottom: 24px; animation: fadeSlideUp 0.6s ease 0.3s both; }
.search-wrap {
  display: flex; align-items: center; gap: 0;
  background: var(--glass2); border: 1px solid var(--border2);
  border-radius: 48px; padding: 6px 6px 6px 20px;
  transition: border-color var(--transition), box-shadow var(--transition);
}
.search-wrap:focus-within {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(0,229,255,0.12);
}
.search-icon { font-size: 1rem; color: var(--text3); flex-shrink: 0; }
.search-wrap input {
  flex: 1; background: none; border: none; outline: none;
  color: var(--text); font-size: 1rem; padding: 4px 12px;
  font-family: inherit;
}
.search-wrap input::placeholder { color: var(--text3); }
.search-btn {
  background: linear-gradient(135deg, var(--accent), var(--accent2));
  border: none; color: #000; font-weight: 700; font-size: 0.9rem;
  padding: 10px 24px; border-radius: 36px; cursor: pointer;
  transition: opacity var(--transition), transform var(--transition);
  font-family: inherit;
}
.search-btn:hover { opacity: 0.88; transform: scale(1.02); }

.search-dropdown {
  position: absolute; top: calc(100% + 8px); left: 0; right: 0;
  background: var(--bg2); border: 1px solid var(--border2);
  border-radius: var(--radius); box-shadow: var(--shadow);
  display: none; z-index: 50; overflow: hidden;
}
.search-dropdown.open { display: block; }

.hero-tags {
  display: flex; flex-wrap: wrap; gap: 10px;
  animation: fadeSlideUp 0.6s ease 0.4s both;
}
.htag {
  background: var(--glass2); border: 1px solid var(--border);
  padding: 6px 16px; border-radius: 24px; font-size: 0.82rem;
  color: var(--text2); transition: all var(--transition);
}
.htag:hover {
  border-color: var(--accent); color: var(--accent);
  background: rgba(0,229,255,0.08);
}

/* --- Hero Visual --- */
.hero-visual {
  flex-shrink: 0; position: relative; width: 280px; height: 420px;
}
.float-card {
  position: absolute; background: var(--glass2);
  border: 1px solid var(--border2); border-radius: var(--radius-sm);
  padding: 10px 18px; font-family: 'JetBrains Mono', monospace;
  font-size: 0.85rem; color: var(--accent); backdrop-filter: blur(12px);
  white-space: nowrap;
}
.fc1 { top: 20px; left: -40px; animation: cardFloat 4s ease-in-out infinite; }
.fc2 { top: 50px; right: -20px; animation: cardFloat 5s ease-in-out infinite 1s; }
.fc3 { bottom: 80px; left: -30px; animation: cardFloat 6s ease-in-out infinite 2s; }
@keyframes cardFloat {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-12px); }
}

/* Beaker Hero */
.beaker-hero {
  position: absolute; bottom: 0; left: 50%; transform: translateX(-50%);
}
.beaker-glass {
  width: 100px; height: 200px; border: 3px solid rgba(0,229,255,0.4);
  border-radius: 4px 4px 12px 12px; position: relative; overflow: hidden;
  background: rgba(0,229,255,0.03);
  box-shadow: 0 0 30px rgba(0,229,255,0.2), inset 0 0 20px rgba(0,229,255,0.05);
}
.beaker-liquid {
  position: absolute; bottom: 0; left: 0; right: 0; height: 60%;
  background: linear-gradient(180deg, rgba(0,229,255,0.6), rgba(0, 180, 255, 0.9));
  transition: height 1s cubic-bezier(0.4, 0, 0.2, 1);
  border-radius: 0 0 9px 9px;
}
.beaker-liquid::before {
  content: ''; position: absolute; top: -6px; left: 0; right: 0; height: 14px;
  background: rgba(255,255,255,0.15); border-radius: 50%;
  animation: wave 2s linear infinite;
}
@keyframes wave {
  0% { transform: translateX(-100%); }
  100% { transform: translateX(100%); }
}
.beaker-bubbles { position: absolute; inset: 0; }
.bb {
  position: absolute; bottom: 10px; width: 6px; height: 6px;
  border-radius: 50%; background: rgba(255,255,255,0.4);
  animation: bubbleRise var(--dur, 2.5s) ease-in infinite var(--delay, 0s);
}
.bb:nth-child(1) { left: 20%; --dur: 2.2s; --delay: 0s; }
.bb:nth-child(2) { left: 40%; --dur: 3s; --delay: 0.5s; }
.bb:nth-child(3) { left: 60%; --dur: 2.5s; --delay: 1s; }
.bb:nth-child(4) { left: 75%; --dur: 2.8s; --delay: 0.3s; }
.bb:nth-child(5) { left: 10%; --dur: 3.2s; --delay: 1.5s; }
@keyframes bubbleRise {
  0% { transform: translateY(0); opacity: 0.8; }
  100% { transform: translateY(-180px); opacity: 0; }
}

/* ============================================
   STATS BAR
   ============================================ */
.stats-bar {
  display: flex; justify-content: center; gap: 0;
  background: var(--bg2); border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}
.stat {
  display: flex; flex-direction: column; align-items: center;
  padding: 28px 48px; gap: 4px;
  border-right: 1px solid var(--border);
}
.stat:last-child { border-right: none; }
.stat-num { font-size: 1.8rem; font-weight: 800; color: var(--accent); }
.stat-label { font-size: 0.8rem; color: var(--text3); font-weight: 500; text-transform: uppercase; letter-spacing: 0.05em; }

/* ============================================
   SECTIONS COMMON
   ============================================ */
.categories, .popular, .learn {
  padding: 100px 0;
}
.popular { background: var(--bg2); }
.learn { background: var(--bg3); }

.section-header {
  text-align: center; margin-bottom: 56px;
}
.section-badge {
  display: inline-block; background: rgba(0,229,255,0.10);
  border: 1px solid rgba(0,229,255,0.25); color: var(--accent);
  padding: 4px 14px; border-radius: 24px; font-size: 0.78rem;
  font-weight: 600; margin-bottom: 14px; text-transform: uppercase;
  letter-spacing: 0.06em;
}
.section-header h2 {
  font-size: clamp(1.8rem, 4vw, 2.8rem); font-weight: 800; margin-bottom: 12px;
}
.section-header p { color: var(--text2); font-size: 1rem; }

/* ============================================
   CATEGORIES GRID
   ============================================ */
.categories-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); gap: 20px;
}
.cat-card {
  background: var(--glass); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 28px;
  transition: all var(--transition); cursor: pointer;
  position: relative; overflow: hidden;
  display: block; color: var(--text); text-decoration: none;
}
.cat-card::before {
  content: ''; position: absolute; inset: 0;
  background: linear-gradient(135deg, rgba(0,229,255,0.04), transparent);
  opacity: 0; transition: opacity var(--transition);
}
.cat-card:hover { border-color: var(--accent); transform: translateY(-4px); box-shadow: 0 12px 40px rgba(0,229,255,0.12); }
.cat-card:hover::before { opacity: 1; }
.cat-card.featured { border-color: rgba(0,229,255,0.2); }
.cat-icon { font-size: 2rem; margin-bottom: 14px; }
.cat-card h3 { font-size: 1.1rem; font-weight: 700; margin-bottom: 8px; }
.cat-card > p { color: var(--text2); font-size: 0.85rem; margin-bottom: 16px; }
.cat-tools {
  list-style: none; display: flex; flex-direction: column; gap: 4px;
  margin-bottom: 16px;
}
.cat-tools li { font-size: 0.82rem; color: var(--text3); padding-left: 10px; position: relative; }
.cat-tools li::before { content: '›'; position: absolute; left: 0; color: var(--accent); }
.cat-tools a, .ctl-link { color: var(--text3); transition: opacity var(--transition); }
.cat-tools a:hover { opacity: 0.7; }
.cat-count {
  display: inline-block; background: rgba(0,229,255,0.08);
  border: 1px solid rgba(0,229,255,0.2); color: var(--accent);
  padding: 3px 10px; border-radius: 12px; font-size: 0.75rem; font-weight: 600;
}
.hot-badge {
  position: absolute; top: 16px; right: 16px;
  background: rgba(239,68,68,0.15); border: 1px solid rgba(239,68,68,0.3);
  color: #fca5a5; padding: 3px 10px; border-radius: 12px; font-size: 0.72rem; font-weight: 600;
}

/* ============================================
   POPULAR GRID
   ============================================ */
.popular-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(320px, 1fr)); gap: 20px;
}
.pop-card {
  display: flex; align-items: center; gap: 20px;
  background: var(--glass); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 28px;
  transition: all var(--transition);
}
.pop-card:hover { border-color: var(--accent); transform: translateY(-3px); box-shadow: 0 12px 40px rgba(0,229,255,0.1); }
.pop-icon { font-size: 2.4rem; flex-shrink: 0; }
.pop-info { flex: 1; }
.pop-info h3 { font-size: 1.05rem; font-weight: 700; margin-bottom: 6px; }
.pop-info p { color: var(--text2); font-size: 0.82rem; margin-bottom: 8px; }
.pop-tag {
  font-family: 'JetBrains Mono', monospace; font-size: 0.78rem;
  color: var(--accent); background: rgba(0,229,255,0.08);
  padding: 3px 10px; border-radius: 8px;
}
.pop-arrow { font-size: 1.4rem; color: var(--accent); transition: transform var(--transition); }
.pop-card:hover .pop-arrow { transform: translateX(4px); }

/* ============================================
   HOMEPAGE POPULAR & BLOG SPLIT
   ============================================ */
.popular-split {
  display: flex; gap: 32px; align-items: flex-start;
}
.popular-main {
  flex: 2.2;
}
.blog-sidebar {
  flex: 1;
}
.blog-side-card {
  background: var(--glass);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 32px;
  position: sticky; top: 100px;
}
.blog-sidebar-title {
  display: flex; align-items: center; justify-content: space-between;
  margin-bottom: 24px;
}
.blog-sidebar-title h3 { font-size: 1.2rem; font-weight: 700; }
.blog-view-all { color: var(--accent); font-size: 0.82rem; font-weight: 600; }

.sidebar-blog-list {
  display: flex; flex-direction: column; gap: 16px;
}
.sidebar-blog-item {
  display: flex; gap: 14px; padding-bottom: 16px;
  border-bottom: 1px solid var(--border);
  transition: transform var(--transition);
}
.sidebar-blog-item:last-child { border-bottom: none; padding-bottom: 0; }
.sidebar-blog-item:hover { transform: translateX(4px); }
.sbi-icon { 
  font-size: 1.25rem; width: 42px; height: 42px; 
  background: var(--glass2); border-radius: 10px;
  display: flex; align-items: center; justify-content: center;
  flex-shrink: 0;
}
.sbi-info h4 { font-size: 0.95rem; font-weight: 600; margin-bottom: 4px; color: var(--text); }
.sbi-info p { font-size: 0.8rem; color: var(--text3); line-height: 1.4; display: -webkit-box; -webkit-line-clamp: 2; line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden; }

@media (max-width: 1000px) {
  .popular-split { flex-direction: column; }
  .popular-main { width: 100%; }
  .blog-sidebar { width: 100%; }
  .blog-side-card { position: static; }
}


/* ============================================
   LEARN GRID
   ============================================ */
.learn-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(300px, 1fr)); gap: 24px;
}
.learn-card {
  background: var(--glass); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 32px;
  transition: all var(--transition);
}
.learn-card:hover { border-color: rgba(124,58,237,0.4); transform: translateY(-3px); }
.learn-icon { font-size: 2rem; margin-bottom: 16px; }
.learn-card h3 { font-size: 1.05rem; font-weight: 700; margin-bottom: 10px; }
.learn-card p { color: var(--text2); font-size: 0.88rem; line-height: 1.7; margin-bottom: 18px; }
.learn-link { color: var(--accent); font-size: 0.88rem; font-weight: 600; transition: opacity var(--transition); }
.learn-link:hover { opacity: 0.7; }

/* ============================================
   FOOTER
   ============================================ */
.footer {
  background: var(--bg); border-top: 1px solid var(--border); padding: 60px 0 30px;
}
.footer-top {
  display: grid; grid-template-columns: 2fr 1fr 1fr; gap: 40px; margin-bottom: 48px;
}
.footer-brand .logo-icon { height: 36px; width: auto; margin-bottom: 8px; display: inline-block; filter: opacity(0.8); }
.footer-brand .logo-text { font-size: 1.3rem; font-weight: 800; }
.footer-brand p { color: var(--text3); font-size: 0.85rem; margin-top: 12px; max-width: 260px; }
.footer-links { display: flex; flex-direction: column; gap: 10px; }
.footer-links h4 { font-size: 0.82rem; font-weight: 600; text-transform: uppercase; letter-spacing: 0.06em; color: var(--text3); margin-bottom: 4px; }
.footer-links a { color: var(--text2); font-size: 0.88rem; transition: color var(--transition); }
.footer-links a:hover { color: var(--accent); }
.footer-bottom { border-top: 1px solid var(--border); padding-top: 24px; text-align: center; }
.footer-bottom p { color: var(--text3); font-size: 0.82rem; }

/* ============================================
   ANIMATIONS
   ============================================ */
@keyframes fadeSlideUp {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}

/* ============================================
   CALCULATOR PAGE SHARED STYLES
   ============================================ */
.calc-page { padding: 100px 0 60px; min-height: 100vh; }
.calc-header { text-align: center; margin-bottom: 48px; padding: 0 24px; }
.calc-header .breadcrumb { color: var(--text3); font-size: 0.82rem; margin-bottom: 12px; }
.calc-header .breadcrumb a { color: var(--accent); }
.calc-header h1 { font-size: clamp(2rem, 5vw, 3rem); font-weight: 900; margin-bottom: 12px; }
.calc-header p { color: var(--text2); font-size: 1rem; max-width: 540px; margin: 0 auto; }

.calc-main {
  display: grid; grid-template-columns: 1fr 1fr; gap: 32px;
  max-width: 1000px; margin: 0 auto; padding: 0 24px;
}

/* Glass Panel */
.glass-panel {
  background: var(--glass); border: 1px solid var(--border2);
  border-radius: var(--radius); padding: 32px;
  backdrop-filter: blur(16px);
}
.glass-panel h2 { font-size: 1.1rem; font-weight: 700; margin-bottom: 24px; color: var(--text); }

/* Input Styles */
.input-group { margin-bottom: 20px; }
.input-label {
  display: flex; align-items: center; justify-content: space-between;
  font-size: 0.82rem; font-weight: 600; color: var(--text2);
  margin-bottom: 8px; text-transform: uppercase; letter-spacing: 0.05em;
}
.input-hint { color: var(--text3); font-weight: 400; text-transform: none; }
.calc-input {
  width: 100%; background: rgba(255,255,255,0.04);
  border: 1px solid var(--border); border-radius: var(--radius-sm);
  padding: 12px 16px; color: var(--text); font-size: 1rem;
  font-family: inherit; outline: none;
  transition: border-color var(--transition), box-shadow var(--transition);
}
.calc-input:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(0,229,255,0.1);
}
.calc-input::placeholder { color: var(--text3); }

.calc-select {
  width: 100%; background: rgba(255,255,255,0.04);
  border: 1px solid var(--border); border-radius: var(--radius-sm);
  padding: 12px 16px; color: var(--text); font-size: 1rem;
  font-family: inherit; outline: none; cursor: pointer;
  transition: border-color var(--transition);
}
.calc-select:focus { border-color: var(--accent); }
.calc-select option { background: var(--bg2); }

.calc-btn {
  width: 100%; background: linear-gradient(135deg, var(--accent), var(--accent2));
  border: none; color: #000; font-weight: 700; font-size: 1rem;
  padding: 14px; border-radius: var(--radius-sm); cursor: pointer;
  font-family: inherit; transition: opacity var(--transition), transform var(--transition);
  margin-top: 8px;
}
.calc-btn:hover { opacity: 0.88; transform: scale(1.01); }
.calc-btn:active { transform: scale(0.99); }

/* Error */
.error-msg {
  background: rgba(239,68,68,0.1); border: 1px solid rgba(239,68,68,0.3);
  color: #fca5a5; padding: 10px 16px; border-radius: var(--radius-sm);
  font-size: 0.85rem; margin-top: 12px; display: none;
}
.error-msg.show { display: block; animation: fadeSlideUp 0.3s ease; }

/* ---- RESULT PANEL ---- */
.result-panel {
  display: flex; flex-direction: column; gap: 24px;
 }

/* Cylinder */
.cylinder-wrap {
  display: flex; flex-direction: column; align-items: center; gap: 16px;
}
.cylinder-container {
  width: 90px; height: 260px; position: relative;
}
.cylinder-body {
  width: 100%; height: 100%; position: relative;
  border: 3px solid rgba(255,255,255,0.15);
  border-radius: 8px 8px 16px 16px;
  background: rgba(255,255,255,0.02);
  overflow: hidden;
  box-shadow: 0 0 30px rgba(0,229,255,0.1), inset 0 0 20px rgba(0,0,0,0.3);
}
/* Scale marks */
.cylinder-body::before {
  content: '';
  position: absolute; right: 8px; top: 0; bottom: 0; width: 2px;
  background: repeating-linear-gradient(
    to bottom, transparent 0, transparent 8px,
    rgba(255,255,255,0.1) 8px, rgba(255,255,255,0.1) 9px
  );
}
.cyl-liquid {
  position: absolute; bottom: 0; left: 0; right: 0;
  height: 0; border-radius: 0 0 13px 13px;
  transition: height 0.8s cubic-bezier(0.4, 0, 0.2, 1),
              background 0.5s ease;
  overflow: hidden;
}
.cyl-liquid::before {
  content: ''; position: absolute; top: 0; left: 0; right: 0; height: 12px;
  background: rgba(255,255,255,0.2); border-radius: 50%;
  animation: liquidWave 2.5s linear infinite;
}
@keyframes liquidWave {
  0% { transform: scaleX(1.2) translateX(-10%); }
  50% { transform: scaleX(0.9) translateX(5%); }
  100% { transform: scaleX(1.2) translateX(-10%); }
}
.cyl-bubbles {
  position: absolute; inset: 0;
}
.cyl-bubble {
  position: absolute; bottom: 0; border-radius: 50%;
  background: rgba(255,255,255,0.3);
  animation: cylBubble var(--dur) ease-in infinite var(--del);
}
@keyframes cylBubble {
  0% { transform: translateY(0) scale(1); opacity: 0.7; }
  100% { transform: translateY(-260px) scale(0.3); opacity: 0; }
}
.cylinder-label { font-size: 0.8rem; color: var(--text3); text-align: center; }

/* Formula Box */
.formula-box {
  background: rgba(0,0,0,0.3); border: 1px solid var(--border);
  border-radius: var(--radius-sm); padding: 16px 20px;
  font-family: 'JetBrains Mono', monospace;
}
.formula-label { font-size: 0.72rem; text-transform: uppercase; letter-spacing: 0.06em; color: var(--text3); margin-bottom: 8px; }
.formula-text { font-size: 1.1rem; color: var(--accent); font-weight: 600; }

/* Result Box */
.result-box {
  background: rgba(0, 229, 255, 0.05); border: 1px solid rgba(0,229,255,0.2);
  border-radius: var(--radius-sm); padding: 20px;
  text-align: center; min-height: 90px;
  display: flex; flex-direction: column; align-items: center; justify-content: center;
  position: relative; overflow: hidden;
}
.result-box::before {
  content: ''; position: absolute; inset: 0;
  background: radial-gradient(circle at 50% 100%, rgba(0,229,255,0.08), transparent 70%);
}
.result-label { font-size: 0.72rem; text-transform: uppercase; letter-spacing: 0.06em; color: var(--text3); margin-bottom: 8px; }
.result-value { font-size: 2.4rem; font-weight: 900; color: var(--accent); font-family: 'JetBrains Mono', monospace; transition: all 0.3s ease; }
.result-unit { font-size: 0.85rem; color: var(--text3); margin-top: 4px; }

.copy-btn {
  background: none; border: 1px solid var(--border); color: var(--text2);
  padding: 8px 20px; border-radius: 24px; font-size: 0.82rem;
  cursor: pointer; font-family: inherit; transition: all var(--transition);
  display: flex; align-items: center; gap: 6px;
}
.copy-btn:hover { border-color: var(--accent); color: var(--accent); }

/* ============================================
   BELOW CALCULATOR CONTENT
   ============================================ */
.calc-content { max-width: 1000px; margin: 48px auto 0; padding: 0 24px; }

.content-block {
  background: var(--glass); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 36px; margin-bottom: 24px;
}
.content-block h2 { font-size: 1.3rem; font-weight: 700; margin-bottom: 16px; }
.content-block h3 { font-size: 1.05rem; font-weight: 600; margin-bottom: 10px; color: var(--accent); }
.content-block p { color: var(--text2); font-size: 0.92rem; line-height: 1.8; margin-bottom: 12px; }
.content-block ul, .content-block ol { padding-left: 20px; color: var(--text2); font-size: 0.92rem; line-height: 1.8; }
.content-block li { margin-bottom: 6px; }

.formula-display {
  background: rgba(0,0,0,0.4); border: 1px solid rgba(0,229,255,0.2);
  border-radius: var(--radius-sm); padding: 20px 24px; margin: 16px 0;
  font-family: 'JetBrains Mono', monospace; font-size: 1.2rem;
  color: var(--accent); text-align: center;
}

/* Example Box */
.example-box {
  background: rgba(16,185,129,0.05); border: 1px solid rgba(16,185,129,0.2);
  border-radius: var(--radius-sm); padding: 20px 24px; margin: 16px 0;
}
.example-box .ex-label { font-size: 0.78rem; text-transform: uppercase; letter-spacing: 0.06em; color: #6ee7b7; font-weight: 600; margin-bottom: 10px; }
.example-box p { color: var(--text2); font-size: 0.9rem; margin-bottom: 6px; }
.example-box .ex-step { color: #6ee7b7; }

/* FAQ */
.faq-item { border-bottom: 1px solid var(--border); padding: 16px 0; }
.faq-item:last-child { border-bottom: none; }
.faq-q { font-weight: 600; font-size: 0.95rem; margin-bottom: 8px; cursor: pointer; display: flex; justify-content: space-between; align-items: center; }
.faq-q::after { content: '+'; color: var(--accent); font-size: 1.2rem; transition: transform var(--transition); }
.faq-item.open .faq-q::after { transform: rotate(45deg); }
.faq-a { color: var(--text2); font-size: 0.88rem; line-height: 1.7; display: none; padding-top: 4px; }
.faq-item.open .faq-a { display: block; animation: fadeSlideUp 0.3s ease; }

/* Internal Links */
.related-links { display: grid; grid-template-columns: repeat(auto-fill, minmax(200px, 1fr)); gap: 12px; margin-top: 16px; }
.related-link {
  display: flex; align-items: center; gap: 10px;
  background: var(--glass2); border: 1px solid var(--border);
  border-radius: var(--radius-sm); padding: 14px 16px;
  font-size: 0.88rem; color: var(--text2);
  transition: all var(--transition);
}
.related-link:hover { border-color: var(--accent); color: var(--accent); }
.related-link .rl-icon { font-size: 1.2rem; }

/* ============================================
   RESPONSIVE
   ============================================ */
@media (max-width: 900px) {
  .hero { flex-direction: column; padding-top: 90px; min-height: auto; gap: 40px; }
  .hero-visual { width: 100%; height: 200px; }
  .float-card { display: none; }
  .beaker-hero { bottom: auto; top: 10px; }
  .calc-main { grid-template-columns: 1fr; }
  .result-panel { flex-direction: row; flex-wrap: wrap; }
  .cylinder-wrap { flex: 0 0 auto; }
  .footer-top { grid-template-columns: 1fr; gap: 28px; }
}

@media (max-width: 600px) {
  .stats-bar { flex-wrap: wrap; }
  .stat { padding: 16px 24px; flex: 1; min-width: 120px; }
  .nav-links { display: flex; gap: 8px; font-size: 0.72rem; }
  .nav-links li a { padding: 4px 8px; }
  .nav-search-mini input { width: 140px; }
  .categories-grid { grid-template-columns: 1fr; }
  .popular-grid { grid-template-columns: 1fr; }
  .learn-grid { grid-template-columns: 1fr; }
  .result-panel { flex-direction: column; }
}

/* ============================================
   PILL TOGGLE (for calculator modes)
   ============================================ */
.pill-toggle {
  display: flex; background: rgba(255,255,255,0.04);
  border: 1px solid var(--border); border-radius: 32px; padding: 4px; gap: 2px;
  margin-bottom: 20px;
}
.pill-btn {
  flex: 1; background: none; border: none; color: var(--text2);
  padding: 8px 12px; border-radius: 28px; font-size: 0.82rem;
  cursor: pointer; font-family: inherit; font-weight: 500;
  transition: all var(--transition); text-align: center;
}
.pill-btn.active {
  background: linear-gradient(135deg, var(--accent), var(--accent2));
  color: #000; font-weight: 700;
}

/* ============================================
   SLIDER INPUT
   ============================================ */
.slider-group { margin-bottom: 20px; }
.slider-row { display: flex; align-items: center; gap: 12px; }
input[type="range"] {
  flex: 1; -webkit-appearance: none; appearance: none; height: 4px;
  background: var(--border2); border-radius: 4px; outline: none;
}
input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none; width: 18px; height: 18px; border-radius: 50%;
  background: var(--accent); cursor: pointer;
  box-shadow: 0 0 10px rgba(0,229,255,0.5);
}
.slider-val {
  font-family: 'JetBrains Mono', monospace; font-size: 0.9rem;
  color: var(--accent); min-width: 60px; text-align: right;
}

/* ============================================
   TAG BUTTON (quick-preset chips on calc pages)
   ============================================ */
.tag-btn {
  background: var(--glass2); border: 1px solid var(--border);
  border-radius: 20px; padding: 4px 12px;
  color: var(--text2); font-size: 0.78rem; font-weight: 500;
  cursor: pointer; font-family: inherit;
  transition: all var(--transition);
}
.tag-btn:hover {
  border-color: var(--accent); color: var(--accent);
  background: rgba(0,229,255,0.08);
}

/* ============================================
   BLOG / ARTICLE SECTION
   ============================================ */
.blog-section {
  max-width: 1000px; margin: 0 auto 60px; padding: 0 24px;
}
.blog-section-inner {
  background: var(--glass); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 48px;
}
.blog-eyebrow {
  display: inline-flex; align-items: center; gap: 6px;
  background: rgba(124,58,237,0.1); border: 1px solid rgba(124,58,237,0.25);
  color: #a78bfa; padding: 4px 14px; border-radius: 24px;
  font-size: 0.75rem; font-weight: 600; margin-bottom: 16px;
  text-transform: uppercase; letter-spacing: 0.07em;
}
.blog-section-inner h2 {
  font-size: clamp(1.5rem, 3vw, 2.1rem); font-weight: 800; margin-bottom: 16px;
  line-height: 1.2;
}
.blog-section-inner h3 {
  font-size: 1.1rem; font-weight: 700; margin: 28px 0 10px; color: var(--accent);
}
.blog-section-inner h4 {
  font-size: 0.95rem; font-weight: 600; margin: 20px 0 8px; color: var(--text);
}
.blog-section-inner p {
  color: var(--text2); font-size: 0.95rem; line-height: 1.85; margin-bottom: 14px;
}
.blog-section-inner ul, .blog-section-inner ol {
  color: var(--text2); font-size: 0.92rem; line-height: 1.85;
  padding-left: 20px; margin-bottom: 14px;
}
.blog-section-inner li { margin-bottom: 6px; }
.blog-section-inner strong { color: var(--text); font-weight: 600; }
.blog-section-inner code {
  font-family: 'JetBrains Mono', monospace; font-size: 0.88em;
  background: rgba(0,229,255,0.08); border: 1px solid rgba(0,229,255,0.15);
  color: var(--accent); padding: 2px 7px; border-radius: 5px;
}

/* TOC */
.blog-toc {
  background: rgba(0,0,0,0.25); border: 1px solid var(--border);
  border-radius: var(--radius-sm); padding: 20px 24px; margin-bottom: 32px;
}
.blog-toc-title {
  font-size: 0.75rem; text-transform: uppercase; letter-spacing: 0.07em;
  color: var(--text3); font-weight: 600; margin-bottom: 12px;
}
.blog-toc ol { padding-left: 16px; margin: 0; }
.blog-toc li { margin-bottom: 4px; }
.blog-toc a { color: var(--accent); font-size: 0.88rem; }
.blog-toc a:hover { opacity: 0.7; }

/* Callout boxes */
.blog-highlight {
  background: rgba(0,229,255,0.05); border-left: 3px solid var(--accent);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  padding: 16px 20px; margin: 20px 0;
}
.blog-highlight p { margin: 0; color: var(--text); }
.blog-tip {
  background: rgba(16,185,129,0.06); border-left: 3px solid #10b981;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  padding: 16px 20px; margin: 20px 0;
}
.blog-tip::before { content: '💡 Pro Tip: '; font-weight: 700; color: #6ee7b7; }
.blog-tip p { margin: 0; color: var(--text2); display: inline; }
.blog-warn {
  background: rgba(245,158,11,0.06); border-left: 3px solid var(--warn);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  padding: 16px 20px; margin: 20px 0;
}
.blog-warn::before { content: '⚠️ Common Mistake: '; font-weight: 700; color: #fcd34d; }
.blog-warn p { margin: 0; color: var(--text2); display: inline; }

/* Info grid */
.blog-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 14px; margin: 20px 0;
}
.blog-grid-item {
  background: rgba(0,0,0,0.3); border: 1px solid var(--border);
  border-radius: var(--radius-sm); padding: 16px; text-align: center;
}
.blog-grid-item .bgi-icon { font-size: 1.6rem; margin-bottom: 8px; }
.blog-grid-item .bgi-label { font-size: 0.75rem; color: var(--text3); text-transform: uppercase; letter-spacing: 0.05em; margin-bottom: 4px; }
.blog-grid-item .bgi-val { font-size: 1rem; font-weight: 700; color: var(--accent); font-family: 'JetBrains Mono', monospace; }

/* Divider */
.blog-divider { border: none; border-top: 1px solid var(--border); margin: 32px 0; }

@media (max-width: 600px) {
  .blog-section-inner { padding: 24px 20px; }
}