/* ============================================================
   SAND ESTIMATOR — Premium Design System
   ============================================================ */

/* --- Google Fonts --- */
@import url('https://fonts.googleapis.com/css2?family=Outfit:wght@300;400;500;600;700;800;900&family=Inter:wght@300;400;500;600;700&display=swap');

/* --- CSS Custom Properties --- */
:root {
  /* Backgrounds */
  --bg-primary: #08080e;
  --bg-secondary: #0e0e18;
  --bg-surface: #141422;
  --bg-card: rgba(20, 20, 34, 0.55);
  --bg-card-hover: rgba(28, 28, 48, 0.7);

  /* Glass */
  --glass-bg: rgba(255, 255, 255, 0.025);
  --glass-bg-strong: rgba(255, 255, 255, 0.05);
  --glass-border: rgba(212, 168, 67, 0.1);
  --glass-border-hover: rgba(212, 168, 67, 0.25);

  /* Primary Colors */
  --color-gold: #d4a843;
  --color-gold-light: #e8c868;
  --color-gold-dim: rgba(212, 168, 67, 0.15);
  --color-amber: #c9956b;
  --color-copper: #b8734a;

  /* Sand Tones */
  --color-sand: #e8d5b7;
  --color-sand-light: #f5efe6;
  --color-sand-dark: #a08c6e;

  /* Text */
  --text-primary: #f5f0eb;
  --text-secondary: #9a9082;
  --text-muted: #5a5248;
  --text-accent: var(--color-gold);

  /* Functional */
  --color-success: #4ade80;
  --color-info: #60a5fa;
  --color-warning: #fbbf24;
  --color-error: #f87171;

  /* Shadows */
  --shadow-sm: 0 2px 8px rgba(0,0,0,0.3);
  --shadow-md: 0 8px 32px rgba(0,0,0,0.4);
  --shadow-lg: 0 16px 64px rgba(0,0,0,0.5);
  --shadow-glow: 0 0 30px rgba(212, 168, 67, 0.15);
  --shadow-glow-strong: 0 0 60px rgba(212, 168, 67, 0.25);

  /* Spacing */
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  --space-3xl: 4rem;
  --space-4xl: 6rem;

  /* Border Radius */
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --radius-full: 9999px;

  /* Transitions */
  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
  --ease-spring: cubic-bezier(0.34, 1.56, 0.64, 1);
  --transition-fast: 0.2s var(--ease-out);
  --transition-normal: 0.4s var(--ease-out);
  --transition-slow: 0.6s var(--ease-out);

  /* Typography */
  --font-heading: 'Outfit', sans-serif;
  --font-body: 'Inter', sans-serif;
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-body);
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.7;
  overflow-x: hidden;
}

::selection {
  background: var(--color-gold);
  color: var(--bg-primary);
}

a {
  color: inherit;
  text-decoration: none;
}

img, svg {
  max-width: 100%;
  display: block;
}

button, input, select, textarea {
  font-family: inherit;
  font-size: inherit;
  color: inherit;
  border: none;
  outline: none;
  background: none;
}

/* --- Scrollbar --- */
::-webkit-scrollbar {
  width: 6px;
}
::-webkit-scrollbar-track {
  background: var(--bg-primary);
}
::-webkit-scrollbar-thumb {
  background: var(--color-gold-dim);
  border-radius: var(--radius-full);
}
::-webkit-scrollbar-thumb:hover {
  background: var(--color-gold);
}

/* --- Utility Classes --- */
.container {
  width: 100%;
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 var(--space-xl);
}

.section-header {
  text-align: center;
  margin-bottom: var(--space-4xl);
}

.section-badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-xs) var(--space-lg);
  border-radius: var(--radius-full);
  background: var(--color-gold-dim);
  border: 1px solid var(--glass-border);
  color: var(--color-gold-light);
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  margin-bottom: var(--space-lg);
}

.section-badge svg {
  width: 14px;
  height: 14px;
}

.section-title {
  font-family: var(--font-heading);
  font-size: clamp(2rem, 5vw, 3.5rem);
  font-weight: 700;
  line-height: 1.15;
  margin-bottom: var(--space-md);
  background: linear-gradient(135deg, var(--text-primary) 0%, var(--color-sand) 50%, var(--color-gold) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.section-subtitle {
  font-size: clamp(1rem, 2vw, 1.15rem);
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto;
  line-height: 1.8;
}

/* --- Glass Card --- */
.glass-card {
  background: var(--glass-bg);
  backdrop-filter: blur(24px);
  -webkit-backdrop-filter: blur(24px);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-lg);
  transition: all var(--transition-normal);
}

.glass-card:hover {
  background: var(--glass-bg-strong);
  border-color: var(--glass-border-hover);
  box-shadow: var(--shadow-glow);
  transform: translateY(-2px);
}

/* --- Scroll Reveal Animation --- */
.reveal {
  opacity: 0;
  transform: translateY(40px);
  transition: opacity 0.8s var(--ease-out), transform 0.8s var(--ease-out);
}

.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

.reveal-delay-1 { transition-delay: 0.1s; }
.reveal-delay-2 { transition-delay: 0.2s; }
.reveal-delay-3 { transition-delay: 0.3s; }
.reveal-delay-4 { transition-delay: 0.4s; }

/* ============================================================
   NAVIGATION
   ============================================================ */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  padding: var(--space-md) 0;
  transition: all var(--transition-normal);
}

.navbar.scrolled {
  background: rgba(8, 8, 14, 0.85);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--glass-border);
  padding: var(--space-sm) 0;
}

.navbar .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 1.4rem;
  color: var(--text-primary);
}

.nav-brand-icon {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-sm);
  background: linear-gradient(135deg, var(--color-gold), var(--color-amber));
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1rem;
}

.nav-brand span {
  background: linear-gradient(135deg, var(--color-gold-light), var(--color-sand));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: var(--space-xl);
  list-style: none;
}

.nav-links a {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-secondary);
  transition: color var(--transition-fast);
  position: relative;
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--color-gold);
  border-radius: var(--radius-full);
  transition: width var(--transition-normal);
}

.nav-links a:hover {
  color: var(--text-primary);
}

.nav-links a:hover::after {
  width: 100%;
}

.nav-cta {
  padding: var(--space-sm) var(--space-lg);
  border-radius: var(--radius-full);
  background: linear-gradient(135deg, var(--color-gold), var(--color-amber));
  color: var(--bg-primary);
  font-weight: 600;
  font-size: 0.85rem;
  cursor: pointer;
  transition: all var(--transition-fast);
  border: none;
}

.nav-cta:hover {
  transform: translateY(-1px);
  box-shadow: var(--shadow-glow-strong);
}

.nav-hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  padding: 4px;
  background: none;
  border: none;
}

.nav-hamburger span {
  width: 24px;
  height: 2px;
  background: var(--text-primary);
  border-radius: 2px;
  transition: all var(--transition-fast);
}

/* ============================================================
   HERO SECTION
   ============================================================ */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  padding: var(--space-4xl) 0;
}

.hero::before {
  content: '';
  position: absolute;
  top: -50%;
  left: -20%;
  width: 140%;
  height: 140%;
  background: radial-gradient(ellipse at 30% 50%, rgba(212, 168, 67, 0.06) 0%, transparent 60%),
              radial-gradient(ellipse at 70% 30%, rgba(201, 149, 107, 0.04) 0%, transparent 50%),
              radial-gradient(ellipse at 50% 80%, rgba(184, 115, 74, 0.03) 0%, transparent 40%);
  pointer-events: none;
  z-index: 1;
}

#sand-canvas {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 0;
  opacity: 0.6;
}

.hero-content {
  position: relative;
  z-index: 2;
  text-align: center;
  max-width: 860px;
  padding: 0 var(--space-xl);
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-sm) var(--space-lg);
  border-radius: var(--radius-full);
  background: var(--color-gold-dim);
  border: 1px solid var(--glass-border);
  color: var(--color-gold-light);
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  margin-bottom: var(--space-2xl);
  animation: fadeInUp 0.8s var(--ease-out) 0.2s both;
}

.hero-badge .pulse-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--color-gold);
  animation: pulse 2s ease-in-out infinite;
}

.hero-title {
  font-family: var(--font-heading);
  font-size: clamp(2.8rem, 7vw, 5.5rem);
  font-weight: 800;
  line-height: 1.05;
  margin-bottom: var(--space-xl);
  animation: fadeInUp 0.8s var(--ease-out) 0.4s both;
}

.hero-title .gradient-text {
  background: linear-gradient(135deg, var(--color-gold-light) 0%, var(--color-gold) 30%, var(--color-amber) 60%, var(--color-copper) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-title .outline-text {
  -webkit-text-stroke: 1.5px var(--color-sand-dark);
  -webkit-text-fill-color: transparent;
}

.hero-description {
  font-size: clamp(1rem, 2vw, 1.2rem);
  color: var(--text-secondary);
  max-width: 580px;
  margin: 0 auto var(--space-2xl);
  line-height: 1.8;
  animation: fadeInUp 0.8s var(--ease-out) 0.6s both;
}

.hero-actions {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-lg);
  margin-bottom: var(--space-4xl);
  animation: fadeInUp 0.8s var(--ease-out) 0.8s both;
}

.btn-primary {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-md) var(--space-2xl);
  border-radius: var(--radius-full);
  background: linear-gradient(135deg, var(--color-gold), var(--color-amber));
  color: var(--bg-primary);
  font-weight: 700;
  font-size: 1rem;
  cursor: pointer;
  transition: all var(--transition-fast);
  border: none;
  position: relative;
  overflow: hidden;
}

.btn-primary::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, var(--color-gold-light), var(--color-gold));
  opacity: 0;
  transition: opacity var(--transition-fast);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-glow-strong);
}

.btn-primary:hover::before {
  opacity: 1;
}

.btn-primary span {
  position: relative;
  z-index: 1;
}

.btn-primary svg {
  position: relative;
  z-index: 1;
  width: 18px;
  height: 18px;
}

.btn-secondary {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-md) var(--space-2xl);
  border-radius: var(--radius-full);
  background: var(--glass-bg);
  backdrop-filter: blur(12px);
  border: 1px solid var(--glass-border);
  color: var(--text-primary);
  font-weight: 600;
  font-size: 1rem;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.btn-secondary:hover {
  background: var(--glass-bg-strong);
  border-color: var(--glass-border-hover);
  transform: translateY(-2px);
}

.btn-secondary svg {
  width: 18px;
  height: 18px;
}

/* Hero Stats */
.hero-stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-xl);
  max-width: 650px;
  margin: 0 auto;
  animation: fadeInUp 0.8s var(--ease-out) 1s both;
}

.stat-item {
  text-align: center;
  padding: var(--space-lg);
  border-radius: var(--radius-md);
  background: var(--glass-bg);
  backdrop-filter: blur(12px);
  border: 1px solid var(--glass-border);
  transition: all var(--transition-normal);
}

.stat-item:hover {
  border-color: var(--glass-border-hover);
  box-shadow: var(--shadow-glow);
}

.stat-number {
  font-family: var(--font-heading);
  font-size: 2rem;
  font-weight: 800;
  color: var(--color-gold-light);
  line-height: 1;
  margin-bottom: var(--space-xs);
}

.stat-label {
  font-size: 0.8rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

/* ============================================================
   CALCULATOR SECTION
   ============================================================ */
.calculator {
  padding: var(--space-4xl) 0;
  position: relative;
}

.calculator::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--glass-border), transparent);
}

.calculator-wrapper {
  background: var(--glass-bg);
  backdrop-filter: blur(24px);
  -webkit-backdrop-filter: blur(24px);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-xl);
  overflow: hidden;
  box-shadow: var(--shadow-lg);
}

/* Calculator Tabs */
.calc-tabs {
  display: flex;
  overflow-x: auto;
  border-bottom: 1px solid var(--glass-border);
  scrollbar-width: none;
}

.calc-tabs::-webkit-scrollbar { display: none; }

.calc-tab {
  flex: 1;
  min-width: 150px;
  padding: var(--space-lg) var(--space-xl);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  font-weight: 600;
  font-size: 0.85rem;
  color: var(--text-secondary);
  cursor: pointer;
  transition: all var(--transition-fast);
  border: none;
  background: none;
  position: relative;
  white-space: nowrap;
}

.calc-tab svg {
  width: 18px;
  height: 18px;
  opacity: 0.6;
  transition: opacity var(--transition-fast);
}

.calc-tab::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 20%;
  right: 20%;
  height: 2px;
  background: var(--color-gold);
  border-radius: var(--radius-full) var(--radius-full) 0 0;
  transform: scaleX(0);
  transition: transform var(--transition-normal);
}

.calc-tab:hover {
  color: var(--text-primary);
  background: rgba(255,255,255,0.02);
}

.calc-tab:hover svg { opacity: 1; }

.calc-tab.active {
  color: var(--color-gold-light);
  background: rgba(212, 168, 67, 0.05);
}

.calc-tab.active svg { opacity: 1; }

.calc-tab.active::after {
  transform: scaleX(1);
}

/* Calculator Body */
.calc-body {
  display: grid;
  grid-template-columns: 1fr 1fr;
  min-height: 480px;
}

.calc-panel {
  display: none;
}

.calc-panel.active {
  display: contents;
}

/* Calculator Inputs */
.calc-inputs {
  padding: var(--space-2xl);
  display: flex;
  flex-direction: column;
  gap: var(--space-lg);
  border-right: 1px solid var(--glass-border);
}

.calc-inputs h3 {
  font-family: var(--font-heading);
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: var(--space-sm);
}

.calc-inputs p {
  font-size: 0.85rem;
  color: var(--text-secondary);
  margin-bottom: var(--space-md);
}

.input-group {
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
}

.input-group label {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.input-group input,
.input-group select {
  padding: var(--space-md) var(--space-lg);
  border-radius: var(--radius-md);
  background: rgba(255, 255, 255, 0.03);
  border: 1px solid var(--glass-border);
  color: var(--text-primary);
  font-size: 0.95rem;
  transition: all var(--transition-fast);
}

.input-group input:focus,
.input-group select:focus {
  border-color: var(--color-gold);
  box-shadow: 0 0 0 3px var(--color-gold-dim);
  background: rgba(255, 255, 255, 0.05);
}

.input-group input::placeholder {
  color: var(--text-muted);
}

.input-group select option {
  background: var(--bg-secondary);
  color: var(--text-primary);
}

.input-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-md);
}

.calc-btn {
  margin-top: auto;
  padding: var(--space-md) var(--space-2xl);
  border-radius: var(--radius-md);
  background: linear-gradient(135deg, var(--color-gold), var(--color-amber));
  color: var(--bg-primary);
  font-weight: 700;
  font-size: 1rem;
  cursor: pointer;
  border: none;
  transition: all var(--transition-fast);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
}

.calc-btn:hover {
  transform: translateY(-1px);
  box-shadow: var(--shadow-glow-strong);
}

.calc-btn svg {
  width: 18px;
  height: 18px;
}

/* Calculator Results */
.calc-results {
  padding: var(--space-2xl);
  display: flex;
  flex-direction: column;
  background: rgba(0,0,0,0.2);
}

.calc-results h3 {
  font-family: var(--font-heading);
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: var(--space-xl);
}

.results-placeholder {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  color: var(--text-muted);
  gap: var(--space-md);
}

.results-placeholder svg {
  width: 64px;
  height: 64px;
  opacity: 0.3;
}

.results-placeholder p {
  font-size: 0.9rem;
}

.result-cards {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-md);
  margin-bottom: var(--space-xl);
}

.result-card {
  padding: var(--space-lg);
  border-radius: var(--radius-md);
  background: rgba(255,255,255,0.03);
  border: 1px solid var(--glass-border);
  transition: all var(--transition-fast);
}

.result-card:hover {
  border-color: var(--glass-border-hover);
}

.result-card .result-value {
  font-family: var(--font-heading);
  font-size: 1.8rem;
  font-weight: 800;
  color: var(--color-gold-light);
  line-height: 1;
}

.result-card .result-unit {
  font-size: 0.9rem;
  color: var(--color-gold);
  font-weight: 600;
}

.result-card .result-label {
  font-size: 0.75rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-top: var(--space-xs);
}

/* Result Visual Bar */
.result-visual {
  margin-top: auto;
}

.result-visual h4 {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-bottom: var(--space-md);
}

.mix-bar {
  display: flex;
  height: 32px;
  border-radius: var(--radius-sm);
  overflow: hidden;
  margin-bottom: var(--space-md);
}

.mix-bar-segment {
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.7rem;
  font-weight: 700;
  color: var(--bg-primary);
  transition: width 0.8s var(--ease-out);
  min-width: 0;
}

.mix-bar-segment.sand {
  background: linear-gradient(135deg, var(--color-gold), var(--color-amber));
}

.mix-bar-segment.cement {
  background: linear-gradient(135deg, #6b7280, #9ca3af);
}

.mix-bar-segment.aggregate {
  background: linear-gradient(135deg, var(--color-sand-dark), var(--color-sand));
}

.mix-legend {
  display: flex;
  gap: var(--space-lg);
  flex-wrap: wrap;
}

.mix-legend-item {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-size: 0.75rem;
  color: var(--text-secondary);
}

.mix-legend-item .dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
}

.mix-legend-item .dot.sand { background: var(--color-gold); }
.mix-legend-item .dot.cement { background: #9ca3af; }
.mix-legend-item .dot.aggregate { background: var(--color-sand-dark); }

/* ============================================================
   INTERACTIVE DIAGRAMS SECTION
   ============================================================ */
.diagrams {
  padding: var(--space-4xl) 0;
  position: relative;
}

.diagrams-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-xl);
}

.diagram-card {
  border-radius: var(--radius-xl);
  overflow: hidden;
  background: var(--glass-bg);
  backdrop-filter: blur(24px);
  border: 1px solid var(--glass-border);
  transition: all var(--transition-normal);
}

.diagram-card:hover {
  border-color: var(--glass-border-hover);
  box-shadow: var(--shadow-glow);
  transform: translateY(-4px);
}

.diagram-svg-wrap {
  padding: var(--space-xl);
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 280px;
  background: rgba(0,0,0,0.2);
  position: relative;
  overflow: hidden;
}

.diagram-svg-wrap svg {
  width: 100%;
  height: auto;
}

.diagram-info {
  padding: var(--space-xl);
}

.diagram-info h3 {
  font-family: var(--font-heading);
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: var(--space-sm);
}

.diagram-info p {
  font-size: 0.85rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

.diagram-info .diagram-tag {
  display: inline-block;
  padding: 2px 10px;
  border-radius: var(--radius-full);
  background: var(--color-gold-dim);
  color: var(--color-gold-light);
  font-size: 0.7rem;
  font-weight: 600;
  margin-top: var(--space-md);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

/* ============================================================
   TOOLS WORKING SECTION
   ============================================================ */
.tools-section {
  padding: var(--space-4xl) 0;
  position: relative;
  background: linear-gradient(180deg, transparent, rgba(212, 168, 67, 0.02), transparent);
}

.tools-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-xl);
}

.tool-card {
  text-align: center;
  padding: var(--space-2xl);
  border-radius: var(--radius-xl);
  background: var(--glass-bg);
  backdrop-filter: blur(24px);
  border: 1px solid var(--glass-border);
  transition: all var(--transition-normal);
  cursor: default;
}

.tool-card:hover {
  border-color: var(--glass-border-hover);
  box-shadow: var(--shadow-glow);
  transform: translateY(-6px);
}

.tool-icon-wrap {
  width: 120px;
  height: 120px;
  margin: 0 auto var(--space-xl);
  border-radius: 50%;
  background: rgba(212, 168, 67, 0.06);
  border: 1px solid var(--glass-border);
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  overflow: hidden;
}

.tool-icon-wrap svg {
  width: 56px;
  height: 56px;
}

.tool-card h3 {
  font-family: var(--font-heading);
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: var(--space-sm);
}

.tool-card p {
  font-size: 0.85rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* Tool Animations */
.tool-mixer .mixer-drum {
  animation: rotateMixer 3s linear infinite;
  transform-origin: center;
}

.tool-trowel .trowel-blade {
  animation: trowelSpread 2s ease-in-out infinite;
}

.tool-wheelbarrow .wheelbarrow-body {
  animation: wheelbarrowDump 3s ease-in-out infinite;
  transform-origin: bottom right;
}

.tool-icon-wrap .sand-particles {
  position: absolute;
  inset: 0;
}

.tool-icon-wrap .sand-particle {
  position: absolute;
  width: 3px;
  height: 3px;
  border-radius: 50%;
  background: var(--color-gold);
  opacity: 0;
}

.tool-card:hover .sand-particle {
  animation: particleFall 1.5s ease-in infinite;
}

.tool-card:hover .sand-particle:nth-child(1) { left: 30%; animation-delay: 0s; }
.tool-card:hover .sand-particle:nth-child(2) { left: 45%; animation-delay: 0.2s; }
.tool-card:hover .sand-particle:nth-child(3) { left: 60%; animation-delay: 0.4s; }
.tool-card:hover .sand-particle:nth-child(4) { left: 50%; animation-delay: 0.6s; }
.tool-card:hover .sand-particle:nth-child(5) { left: 35%; animation-delay: 0.8s; }

/* ============================================================
   HOW IT WORKS SECTION
   ============================================================ */
.how-it-works {
  padding: var(--space-4xl) 0;
}

.steps-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-xl);
  position: relative;
}

.steps-grid::before {
  content: '';
  position: absolute;
  top: 56px;
  left: 12%;
  right: 12%;
  height: 2px;
  background: linear-gradient(90deg, var(--color-gold-dim), var(--color-gold), var(--color-gold-dim));
  z-index: 0;
}

.step-card {
  text-align: center;
  position: relative;
  z-index: 1;
}

.step-number {
  width: 56px;
  height: 56px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--color-gold), var(--color-amber));
  color: var(--bg-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 1.2rem;
  margin: 0 auto var(--space-xl);
  box-shadow: var(--shadow-glow);
  position: relative;
}

.step-number::after {
  content: '';
  position: absolute;
  inset: -4px;
  border-radius: 50%;
  border: 2px solid var(--color-gold-dim);
}

.step-card h3 {
  font-family: var(--font-heading);
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: var(--space-sm);
}

.step-card p {
  font-size: 0.85rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* ============================================================
   MATERIALS GUIDE SECTION
   ============================================================ */
.materials {
  padding: var(--space-4xl) 0;
}

.materials-table-wrap {
  overflow-x: auto;
  border-radius: var(--radius-xl);
  background: var(--glass-bg);
  backdrop-filter: blur(24px);
  border: 1px solid var(--glass-border);
}

.materials-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9rem;
}

.materials-table thead {
  background: rgba(212, 168, 67, 0.06);
}

.materials-table th {
  padding: var(--space-lg) var(--space-xl);
  text-align: left;
  font-weight: 700;
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-gold-light);
  border-bottom: 1px solid var(--glass-border);
  white-space: nowrap;
}

.materials-table td {
  padding: var(--space-lg) var(--space-xl);
  border-bottom: 1px solid rgba(255,255,255,0.03);
  color: var(--text-secondary);
}

.materials-table tbody tr {
  transition: background var(--transition-fast);
}

.materials-table tbody tr:hover {
  background: rgba(212, 168, 67, 0.03);
}

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

.sand-type-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-weight: 600;
  color: var(--text-primary);
}

.sand-type-badge .color-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
}

.grade-pill {
  padding: 2px 10px;
  border-radius: var(--radius-full);
  font-size: 0.75rem;
  font-weight: 600;
}

.grade-fine {
  background: rgba(212, 168, 67, 0.12);
  color: var(--color-gold-light);
}

.grade-medium {
  background: rgba(201, 149, 107, 0.15);
  color: var(--color-amber);
}

.grade-coarse {
  background: rgba(184, 115, 74, 0.15);
  color: var(--color-copper);
}

.use-tag {
  display: inline-block;
  padding: 2px 8px;
  border-radius: var(--radius-sm);
  background: rgba(255,255,255,0.04);
  border: 1px solid rgba(255,255,255,0.06);
  font-size: 0.75rem;
  color: var(--text-secondary);
  margin: 2px;
}

/* ============================================================
   FOOTER
   ============================================================ */
.footer {
  padding: var(--space-4xl) 0 var(--space-xl);
  border-top: 1px solid var(--glass-border);
  background: rgba(0,0,0,0.3);
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: var(--space-2xl);
  margin-bottom: var(--space-3xl);
}

.footer-brand p {
  color: var(--text-secondary);
  font-size: 0.85rem;
  line-height: 1.8;
  margin-top: var(--space-md);
  max-width: 320px;
}

.footer-col h4 {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 0.9rem;
  color: var(--text-primary);
  margin-bottom: var(--space-lg);
}

.footer-col ul {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.footer-col a {
  font-size: 0.85rem;
  color: var(--text-secondary);
  transition: color var(--transition-fast);
}

.footer-col a:hover {
  color: var(--color-gold);
}

.footer-bottom {
  padding-top: var(--space-xl);
  border-top: 1px solid rgba(255,255,255,0.04);
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.8rem;
  color: var(--text-muted);
}

/* ============================================================
   KEYFRAME ANIMATIONS
   ============================================================ */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes pulse {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.5; transform: scale(0.8); }
}

@keyframes rotateMixer {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}

@keyframes trowelSpread {
  0%, 100% { transform: translateX(0) rotate(0deg); }
  50% { transform: translateX(8px) rotate(-5deg); }
}

@keyframes wheelbarrowDump {
  0%, 60%, 100% { transform: rotate(0deg); }
  30% { transform: rotate(-15deg); }
}

@keyframes particleFall {
  0% { top: 20%; opacity: 0; }
  20% { opacity: 0.8; }
  100% { top: 85%; opacity: 0; }
}

@keyframes shimmer {
  0% { background-position: -200% center; }
  100% { background-position: 200% center; }
}

@keyframes float {
  0%, 100% { transform: translateY(0px); }
  50% { transform: translateY(-8px); }
}

@keyframes drawLine {
  to { stroke-dashoffset: 0; }
}

/* ============================================================
   FORMULAS & THEORY SECTION
   ============================================================ */
.formulas-section {
  padding: var(--space-4xl) 0;
  position: relative;
  background: var(--bg-color);
}

.formulas-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--space-xl);
  margin-top: var(--space-2xl);
}

.formula-card {
  background: var(--glass-bg);
  backdrop-filter: blur(12px);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-lg);
  padding: var(--space-xl);
  transition: all var(--transition-normal);
  display: flex;
  flex-direction: column;
}

.formula-card:hover {
  transform: translateY(-5px);
  border-color: var(--color-gold);
  box-shadow: var(--shadow-glow);
}

.formula-icon {
  font-size: 2.5rem;
  margin-bottom: var(--space-md);
}

.formula-card h3 {
  font-family: var(--font-heading);
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: var(--space-sm);
}

.formula-card p {
  color: var(--text-secondary);
  font-size: 0.9rem;
  line-height: 1.6;
  margin-bottom: var(--space-lg);
  flex-grow: 1;
}

.formula-math {
  background: rgba(10, 10, 15, 0.6);
  border: 1px solid rgba(255, 255, 255, 0.05);
  padding: var(--space-md);
  border-radius: var(--radius-md);
  font-family: 'Courier New', Courier, monospace;
  font-size: 0.9rem;
  text-align: center;
  margin-bottom: var(--space-sm);
  color: #fff;
}

.formula-math .var {
  color: var(--color-gold-light);
}

.formula-math .const {
  color: #6ee7b7; /* subtle green for constants */
  font-weight: bold;
}

.formula-note {
  font-size: 0.75rem !important;
  color: var(--text-muted) !important;
  margin-bottom: 0 !important;
  font-style: italic;
}


/* ============================================================
   RESPONSIVE DESIGN
   ============================================================ */
@media (max-width: 1024px) {
  .diagrams-grid {
    grid-template-columns: 1fr;
    max-width: 500px;
    margin: 0 auto;
  }

  .tools-grid {
    grid-template-columns: 1fr 1fr;
  }

  .steps-grid {
    grid-template-columns: 1fr 1fr;
    gap: var(--space-2xl);
  }

  .steps-grid::before {
    display: none;
  }

  .footer-grid {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 768px) {
  .container {
    padding: 0 var(--space-lg);
  }

  .nav-links {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    flex-direction: column;
    background: rgba(8, 8, 14, 0.95);
    backdrop-filter: blur(20px);
    padding: var(--space-xl);
    border-bottom: 1px solid var(--glass-border);
    gap: var(--space-md);
  }

  .nav-links.open { display: flex; }

  .nav-hamburger { display: flex; }

  .nav-cta { display: none; }

  .hero-title {
    font-size: clamp(2rem, 8vw, 3rem);
  }

  .hero-actions {
    flex-direction: column;
  }

  .hero-stats {
    grid-template-columns: 1fr;
    gap: var(--space-md);
  }

  .calc-body {
    grid-template-columns: 1fr;
  }

  .calc-inputs {
    border-right: none;
    border-bottom: 1px solid var(--glass-border);
  }

  .input-row {
    grid-template-columns: 1fr;
  }

  .result-cards {
    grid-template-columns: 1fr;
  }

  .tools-grid {
    grid-template-columns: 1fr;
  }

  .steps-grid {
    grid-template-columns: 1fr;
  }

  .footer-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 480px) {
  .calc-tab {
    padding: var(--space-md);
    min-width: 120px;
    font-size: 0.75rem;
  }

  .calc-tab svg {
    width: 14px;
    height: 14px;
  }
}

/* ============================================================
   CALCULATOR DIRECTORY HUB & CATEGORY FILTERS
   ============================================================ */
.calc-hub-section {
  padding: var(--space-4xl) 0;
  position: relative;
  background: linear-gradient(180deg, var(--bg-primary) 0%, #0d0d16 50%, var(--bg-primary) 100%);
}

.hub-controls {
  margin: var(--space-2xl) 0;
  display: flex;
  flex-direction: column;
  gap: var(--space-lg);
  align-items: center;
}

.hub-search-box {
  width: 100%;
  max-width: 520px;
  position: relative;
}

.hub-search-input {
  width: 100%;
  padding: 0.9rem 1.25rem 0.9rem 3rem;
  background: rgba(20, 20, 34, 0.7);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-full);
  color: var(--text-primary);
  font-family: var(--font-body);
  font-size: 0.95rem;
  transition: var(--transition-fast);
  backdrop-filter: blur(12px);
}

.hub-search-input:focus {
  outline: none;
  border-color: var(--color-gold);
  box-shadow: 0 0 20px rgba(212, 168, 67, 0.25);
  background: rgba(26, 26, 44, 0.9);
}

.hub-search-icon {
  position: absolute;
  left: 1.1rem;
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-muted);
  width: 18px;
  height: 18px;
  pointer-events: none;
}

.hub-filters {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.5rem;
  max-width: 1050px;
}

.hub-filter-btn {
  background: rgba(255, 255, 255, 0.03);
  border: 1px solid rgba(255, 255, 255, 0.08);
  color: var(--text-secondary);
  padding: 0.55rem 1.15rem;
  border-radius: var(--radius-full);
  font-size: 0.85rem;
  font-weight: 500;
  cursor: pointer;
  transition: var(--transition-fast);
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
}

.hub-filter-btn:hover {
  background: rgba(212, 168, 67, 0.1);
  border-color: var(--glass-border-hover);
  color: var(--color-gold-light);
  transform: translateY(-2px);
}

.hub-filter-btn.active {
  background: linear-gradient(135deg, rgba(212, 168, 67, 0.25), rgba(201, 149, 107, 0.2));
  border-color: var(--color-gold);
  color: #fff;
  box-shadow: 0 0 16px rgba(212, 168, 67, 0.25);
}

.hub-count-badge {
  background: rgba(0, 0, 0, 0.4);
  color: var(--color-gold);
  font-size: 0.72rem;
  padding: 0.15rem 0.5rem;
  border-radius: var(--radius-full);
  font-weight: 700;
}

/* Hub Grid */
.hub-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: var(--space-xl);
  margin-top: var(--space-2xl);
}

.hub-card {
  background: var(--bg-card);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  display: flex;
  flex-direction: column;
  position: relative;
  overflow: hidden;
  transition: all 0.35s var(--ease-out);
  backdrop-filter: blur(16px);
  text-decoration: none;
  color: inherit;
}

.hub-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, transparent, var(--color-gold), transparent);
  opacity: 0;
  transition: opacity 0.3s ease;
}

.hub-card:hover {
  transform: translateY(-6px);
  border-color: var(--glass-border-hover);
  background: var(--bg-card-hover);
  box-shadow: 0 16px 40px rgba(0, 0, 0, 0.5), 0 0 28px rgba(212, 168, 67, 0.2);
}

.hub-card:hover::before {
  opacity: 1;
}

/* Card Visual Thumbnail / Image Container */
.hub-card-thumb {
  width: 100%;
  height: 110px;
  border-radius: var(--radius-md);
  background: linear-gradient(135deg, rgba(22, 22, 38, 0.95), rgba(12, 12, 20, 0.98));
  border: 1px solid rgba(212, 168, 67, 0.15);
  margin-bottom: var(--space-md);
  overflow: hidden;
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: inset 0 0 20px rgba(0, 0, 0, 0.5);
}

.hub-card-thumb svg {
  width: 100%;
  height: 100%;
  transition: transform 0.4s var(--ease-out);
}

.hub-card:hover .hub-card-thumb svg {
  transform: scale(1.06);
}

.hub-card:hover .hub-card-thumb {
  border-color: rgba(212, 168, 67, 0.4);
  box-shadow: inset 0 0 25px rgba(212, 168, 67, 0.15), 0 4px 20px rgba(0, 0, 0, 0.4);
}

.hub-card-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--space-sm);
}

.hub-card-icon {
  width: 32px;
  height: 32px;
  border-radius: var(--radius-sm);
  background: linear-gradient(135deg, rgba(212, 168, 67, 0.2), rgba(201, 149, 107, 0.08));
  border: 1px solid rgba(212, 168, 67, 0.25);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-gold-light);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.2);
}

.hub-card-icon svg {
  width: 18px;
  height: 18px;
}

.hub-card:hover .hub-card-icon {
  transform: scale(1.08) rotate(3deg);
  background: linear-gradient(135deg, rgba(212, 168, 67, 0.3), rgba(201, 149, 107, 0.15));
  border-color: var(--color-gold);
  box-shadow: 0 0 20px rgba(212, 168, 67, 0.35);
}

.hub-card-category {
  font-size: 0.72rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  padding: 0.25rem 0.65rem;
  border-radius: var(--radius-full);
  background: rgba(255, 255, 255, 0.04);
  color: var(--text-muted);
  border: 1px solid rgba(255, 255, 255, 0.06);
}

.hub-card-title {
  font-family: var(--font-heading);
  font-size: 1.15rem;
  font-weight: 700;
  color: #fff;
  margin-bottom: var(--space-xs);
  line-height: 1.35;
  transition: color 0.2s ease;
}

.hub-card:hover .hub-card-title {
  color: var(--color-gold-light);
}

.hub-card-desc {
  font-size: 0.85rem;
  color: var(--text-secondary);
  line-height: 1.5;
  margin-bottom: var(--space-lg);
  flex-grow: 1;
}

.hub-card-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
  margin-bottom: var(--space-lg);
}

.hub-tag {
  font-size: 0.7rem;
  padding: 0.15rem 0.45rem;
  border-radius: 4px;
  background: rgba(212, 168, 67, 0.08);
  color: var(--color-gold);
  border: 1px solid rgba(212, 168, 67, 0.15);
}

.hub-card-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-top: var(--space-md);
  border-top: 1px solid rgba(255, 255, 255, 0.05);
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--color-gold);
}

.hub-card-arrow {
  display: flex;
  align-items: center;
  gap: 0.35rem;
  transition: transform 0.25s ease;
}

.hub-card:hover .hub-card-arrow {
  transform: translateX(4px);
  color: var(--color-gold-light);
}

/* ============================================================
   STANDALONE CALCULATOR PAGE STYLES
   ============================================================ */
.page-hero {
  padding: calc(var(--space-4xl) + 40px) 0 var(--space-2xl);
  position: relative;
  background: radial-gradient(circle at 50% 20%, rgba(212, 168, 67, 0.08), transparent 70%), var(--bg-primary);
  border-bottom: 1px solid var(--glass-border);
}

.breadcrumbs {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: var(--space-lg);
  flex-wrap: wrap;
}

.breadcrumbs a {
  color: var(--text-secondary);
  text-decoration: none;
  transition: color 0.2s ease;
}

.breadcrumbs a:hover {
  color: var(--color-gold);
}

.breadcrumbs .separator {
  color: var(--text-muted);
  font-size: 0.75rem;
}

.breadcrumbs .current {
  color: var(--color-gold);
  font-weight: 600;
}

.page-title-wrap {
  display: flex;
  align-items: center;
  gap: var(--space-lg);
  margin-bottom: var(--space-md);
}

.page-icon-badge {
  width: 64px;
  height: 64px;
  border-radius: var(--radius-lg);
  background: linear-gradient(135deg, rgba(212, 168, 67, 0.25), rgba(201, 149, 107, 0.1));
  border: 1px solid var(--color-gold);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-gold-light);
  box-shadow: 0 0 24px rgba(212, 168, 67, 0.25);
  flex-shrink: 0;
}

.page-icon-badge svg {
  width: 34px;
  height: 34px;
}

.standalone-calc-container {
  padding: var(--space-3xl) 0;
}

.calc-guide-section {
  padding: var(--space-3xl) 0;
  border-top: 1px solid var(--glass-border);
  background: rgba(10, 10, 18, 0.5);
}

.guide-grid {
  display: grid;
  grid-template-columns: 2fr 1fr;
  gap: var(--space-2xl);
  margin-top: var(--space-xl);
}

.guide-content h3 {
  font-family: var(--font-heading);
  font-size: 1.3rem;
  color: #fff;
  margin-top: var(--space-xl);
  margin-bottom: var(--space-sm);
}

.guide-content h3:first-child {
  margin-top: 0;
}

.guide-content p {
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: var(--space-md);
  font-size: 0.95rem;
}

.guide-content ul, .guide-content ol {
  color: var(--text-secondary);
  line-height: 1.7;
  margin-left: 1.25rem;
  margin-bottom: var(--space-lg);
}

.guide-content li {
  margin-bottom: 0.35rem;
}

.guide-sidebar {
  display: flex;
  flex-direction: column;
  gap: var(--space-xl);
}

.sidebar-card {
  background: var(--bg-card);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  backdrop-filter: blur(16px);
}

.sidebar-card h4 {
  font-family: var(--font-heading);
  color: var(--color-gold-light);
  font-size: 1.05rem;
  margin-bottom: var(--space-md);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.sidebar-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.sidebar-list li {
  margin-bottom: 0.6rem;
}

.sidebar-list a {
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 0.88rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.4rem 0.6rem;
  border-radius: var(--radius-sm);
  transition: all 0.2s ease;
}

.sidebar-list a:hover {
  color: var(--color-gold);
  background: rgba(212, 168, 67, 0.08);
  transform: translateX(3px);
}

/* FAQ Accordion */
.faq-section {
  padding: var(--space-3xl) 0;
  border-top: 1px solid var(--glass-border);
}

.faq-grid {
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
  max-width: 860px;
  margin: var(--space-xl) auto 0;
}

.faq-card {
  background: var(--bg-card);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: border-color 0.2s ease;
}

.faq-card:hover {
  border-color: var(--glass-border-hover);
}

.faq-question {
  padding: var(--space-lg);
  display: flex;
  justify-content: space-between;
  align-items: center;
  cursor: pointer;
  font-weight: 600;
  color: #fff;
  font-size: 1rem;
}

.faq-icon {
  width: 20px;
  height: 20px;
  color: var(--color-gold);
  transition: transform 0.3s ease;
}

.faq-card.open .faq-icon {
  transform: rotate(180deg);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.35s ease, padding 0.35s ease;
  padding: 0 var(--space-lg);
  color: var(--text-secondary);
  font-size: 0.9rem;
  line-height: 1.6;
}

.faq-card.open .faq-answer {
  max-height: 400px;
  padding: 0 var(--space-lg) var(--space-lg);
}

@media (max-width: 900px) {
  .guide-grid {
    grid-template-columns: 1fr;
  }
}