/* ============================================
   THE CORE CENTER - Industrial Minimalist
   Palette: Gold / Forest / Matte Black
   Philosophy: The 7-Minute Rule
   ============================================ */

:root {
  --gold: #C9A24B;
  --gold-light: #E5C277;
  --gold-dark: #9B7A2E;
  --forest: #2E4A3B;
  --forest-light: #3F6652;
  --forest-dark: #1C2E24;
  --matte-black: #0E0E10;
  --coal: #1A1A1D;
  --steel: #2A2A2E;
  --ash: #6B6B70;
  --paper: #EDE9E0;
  --paper-dim: #C7C2B6;
  --white-soft: #F7F4EC;

  --font-display: 'Barlow Condensed', 'Inter', sans-serif;
  --font-body: 'Inter', system-ui, sans-serif;
  --font-mono: 'JetBrains Mono', monospace;

  --radius-sm: 2px;
  --radius-md: 4px;
  --radius-lg: 8px;

  --shadow-hard: 0 2px 0 var(--matte-black), 0 6px 20px rgba(0,0,0,0.35);
  --shadow-gold: 0 0 0 1px var(--gold), 0 10px 30px rgba(201,162,75,0.25);

  --pipe: 2px solid var(--gold);
  --joint: 3px solid var(--gold);

  --ease-industrial: cubic-bezier(0.7, 0, 0.3, 1);
}

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

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-body);
  background: var(--matte-black);
  color: var(--paper);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

/* Industrial texture overlay */
body::before {
  content: '';
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 1;
  background-image:
    radial-gradient(circle at 1px 1px, rgba(201,162,75,0.04) 1px, transparent 0);
  background-size: 24px 24px;
  opacity: 0.6;
}

h1, h2, h3, h4, h5 {
  font-family: var(--font-display);
  font-weight: 600;
  letter-spacing: 0.02em;
  line-height: 1.1;
  color: var(--white-soft);
  text-transform: uppercase;
}

h1 { font-size: clamp(2.4rem, 5vw, 4.5rem); }
h2 { font-size: clamp(1.8rem, 3.5vw, 2.8rem); }
h3 { font-size: clamp(1.3rem, 2vw, 1.6rem); }

a { color: var(--gold); text-decoration: none; transition: color 0.2s; }
a:hover { color: var(--gold-light); }

.mono { font-family: var(--font-mono); font-size: 0.85em; letter-spacing: 0.05em; }

/* ============================================
   LAYOUT — PIPE GRID
   ============================================ */
.container {
  max-width: 1440px;
  margin: 0 auto;
  padding: 0 2rem;
  position: relative;
  z-index: 2;
}

.section {
  padding: 6rem 0;
  position: relative;
}

.section-label {
  display: inline-flex;
  align-items: center;
  gap: 0.75rem;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.2em;
  color: var(--gold);
  margin-bottom: 1rem;
}
.section-label::before {
  content: '';
  width: 24px; height: 1px;
  background: var(--gold);
}

/* ============================================
   HEADER / NAV — Pipe & Joint
   ============================================ */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(14, 14, 16, 0.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(201,162,75,0.2);
}
.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 1rem;
  padding-bottom: 1rem;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.25rem;
  color: var(--white-soft);
  text-transform: uppercase;
  letter-spacing: 0.08em;
}
.brand-mark {
  width: 36px; height: 36px;
  display: grid; place-items: center;
  border: 2px solid var(--gold);
  border-radius: 50%;
}
.brand-mark svg { width: 22px; height: 22px; stroke: var(--gold); }
.brand small {
  display: block;
  font-size: 0.65rem;
  color: var(--ash);
  font-weight: 400;
  letter-spacing: 0.2em;
}

/* ===== NHẬT KHÊ Co.,Ltd brand logo ===== */
.brand--nk { gap: .85rem; }
.brand-mark--nk {
  width: 36px; height: 36px;
  border: none;
  border-radius: 0;
  background: transparent;
  filter: drop-shadow(0 2px 4px rgba(0,0,0,.5));
  display: inline-flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}
.brand-mark--nk img {
  width: 100%;
  height: 100%;
  object-fit: contain;
  display: block;
}
.brand-mark--nk svg {
  width: 100%; height: 100%;
  stroke: none;
}
.brand-text--nk {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.15rem;
  color: var(--white-soft);
  letter-spacing: .06em;
  line-height: 1.1;
  text-transform: uppercase;
}
.brand-text__co {
  color: var(--white-soft);
  font-weight: 600;
  letter-spacing: .04em;
  text-transform: none;
}
.brand-text--nk small {
  display: block;
  font-size: 0.6rem;
  color: var(--ash);
  font-weight: 400;
  letter-spacing: 0.18em;
  margin-top: 2px;
  text-transform: uppercase;
}

.nav {
  display: flex;
  gap: 2rem;
  align-items: center;
}
.nav a {
  color: var(--paper-dim);
  font-size: 0.8rem;
  font-family: var(--font-mono);
  letter-spacing: 0.15em;
  text-transform: uppercase;
  padding: 0.5rem 0;
  position: relative;
}
.nav a:hover, .nav a.active { color: var(--gold); }
.nav a.active::after {
  content: '';
  position: absolute;
  left: 0; right: 0; bottom: -4px;
  height: 2px; background: var(--gold);
}

.cart-toggle {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  background: var(--gold);
  color: var(--matte-black);
  border: none;
  padding: 0.6rem 1rem;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  cursor: pointer;
  transition: transform 0.2s, background 0.2s;
}
.cart-toggle:hover { background: var(--gold-light); transform: translateY(-1px); }
.cart-count {
  background: var(--matte-black);
  color: var(--gold);
  padding: 0.1rem 0.5rem;
  font-size: 0.7rem;
  min-width: 20px;
  text-align: center;
}

/* Mobile nav toggle */
.nav-toggle {
  display: none;
  background: transparent;
  border: 1px solid var(--gold);
  color: var(--gold);
  padding: 0.5rem 0.75rem;
  cursor: pointer;
}

/* ============================================
   HERO — HEXAGRAM CORE CENTER
   ============================================ */
.hero {
  min-height: 100vh;
  display: grid;
  place-items: center;
  position: relative;
  padding: 4rem 1rem 2rem;
  overflow: hidden;
}
.hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse at center, rgba(46,74,59,0.25) 0%, transparent 60%),
    linear-gradient(180deg, transparent 0%, var(--matte-black) 100%);
}

.hero-inner {
  position: relative;
  z-index: 2;
  text-align: center;
  width: 100%;
  max-width: 900px;
}

.hero-kicker {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--gold);
  letter-spacing: 0.3em;
  text-transform: uppercase;
  margin-bottom: 1rem;
  display: inline-block;
  padding: 0.4rem 1rem;
  border: 1px solid rgba(201,162,75,0.3);
}

.hero-title {
  font-size: clamp(2.2rem, 6vw, 4.5rem);
  font-weight: 700;
  margin-bottom: 0.5rem;
}
.hero-title span { color: var(--white-soft); }

.hero-subtitle {
  color: var(--paper-dim);
  max-width: 600px;
  margin: 0.5rem auto 2rem;
  font-size: 1rem;
}

/* Hexagram SVG stage */
.hexagram-stage {
  position: relative;
  width: min(92vw, 640px);
  aspect-ratio: 1;
  margin: 1rem auto;
}
.hexagram-stage svg {
  width: 100%;
  height: 100%;
  overflow: visible;
}

.hex-outer-ring {
  fill: none;
  stroke: rgba(201,162,75,0.25);
  stroke-width: 1;
  stroke-dasharray: 4 8;
  transform-origin: center;
  animation: spin-slow 60s linear infinite;
}
@keyframes spin-slow { to { transform: rotate(360deg); } }

.hex-triangle {
  fill: rgba(26,26,29,0.5);
  stroke: var(--gold);
  stroke-width: 1.5;
  stroke-linejoin: round;
  transition: all 0.5s var(--ease-industrial);
  cursor: pointer;
}
.hex-triangle:hover { fill: rgba(201,162,75,0.1); }

.hex-vertex {
  cursor: pointer;
  transition: all 0.3s var(--ease-industrial);
}
.hex-vertex circle.vertex-bg {
  fill: var(--matte-black);
  stroke: var(--gold);
  stroke-width: 2.25;
  transition: fill 0.3s, stroke-width 0.3s, filter 0.3s;
}
.hex-vertex text {
  fill: var(--white-soft);
  font-family: var(--font-display);
  font-size: 9px;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-anchor: middle;
  text-transform: uppercase;
  pointer-events: none;
  user-select: none;
}
.hex-vertex text.vertex-label-inside {
  fill: var(--white-soft);
  font-size: 9px;
  font-weight: 700;
  letter-spacing: 0.04em;
}

.hex-vertex:hover circle.vertex-bg,
.hex-vertex.active circle.vertex-bg {
  fill: var(--gold);
  stroke-width: 3;
  filter: drop-shadow(0 0 10px rgba(201,162,75,0.55));
}
.hex-vertex:hover text,
.hex-vertex.active text {
  fill: var(--matte-black);
}

.hex-triangle.active-tri {
  fill: rgba(201,162,75,0.35);
  stroke: var(--gold-light);
  stroke-width: 2.5;
  filter: drop-shadow(0 0 12px rgba(201,162,75,0.5));
}

.hex-core {
  fill: var(--forest-dark);
  stroke: var(--gold);
  stroke-width: 2;
}
.hex-core-inner {
  fill: var(--matte-black);
  stroke: rgba(201,162,75,0.4);
  stroke-width: 1;
  stroke-dasharray: 2 4;
}

/* Core center HTML overlay */
.core-overlay {
  position: absolute;
  top: 50%; left: 50%;
  transform: translate(-50%, -50%);
  width: 30%;
  text-align: center;
  pointer-events: none;
}
.core-overlay .core-title {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--gold);
  letter-spacing: 0.2em;
  text-transform: uppercase;
}
.core-overlay .core-value {
  font-family: var(--font-display);
  font-size: clamp(1rem, 2vw, 1.4rem);
  color: var(--white-soft);
  margin: 0.25rem 0;
  text-transform: uppercase;
}
.core-overlay .core-sub {
  font-family: var(--font-mono);
  font-size: 0.65rem;
  color: var(--paper-dim);
}

.hero-stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 1px;
  background: rgba(201,162,75,0.2);
  margin-top: 2rem;
  border: 1px solid rgba(201,162,75,0.2);
}
.hero-stats .stat {
  background: var(--coal);
  padding: 1rem;
  text-align: center;
}
.hero-stats .stat-val {
  font-family: var(--font-display);
  font-size: 1.6rem;
  color: var(--gold);
  display: block;
}
.hero-stats .stat-lbl {
  font-family: var(--font-mono);
  font-size: 0.65rem;
  color: var(--paper-dim);
  letter-spacing: 0.15em;
  text-transform: uppercase;
}

/* ============================================
   BUTTONS
   ============================================ */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.85rem 1.5rem;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  border: 2px solid var(--gold);
  background: transparent;
  color: var(--gold);
  cursor: pointer;
  transition: all 0.3s var(--ease-industrial);
  text-decoration: none;
  position: relative;
  overflow: hidden;
}
.btn::before {
  content: '';
  position: absolute;
  inset: 0;
  background: var(--gold);
  transform: translateX(-101%);
  transition: transform 0.3s var(--ease-industrial);
  z-index: -1;
}
.btn:hover { color: var(--matte-black); }
.btn:hover::before { transform: translateX(0); }

.btn-primary {
  background: var(--gold);
  color: var(--matte-black);
}
.btn-primary::before { background: var(--gold-light); }
.btn-primary:hover { color: var(--matte-black); border-color: var(--gold-light); }

.btn-ghost {
  border-color: rgba(201,162,75,0.4);
  color: var(--paper-dim);
}
.btn-ghost::before { background: var(--steel); }
.btn-ghost:hover { color: var(--gold); border-color: var(--gold); }

.btn-sm { padding: 0.6rem 1rem; font-size: 0.7rem; }

/* ============================================
   CARDS & GRIDS
   ============================================ */
.grid {
  display: grid;
  gap: 1.5rem;
}
.grid-3 { grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); }
.grid-2 { grid-template-columns: repeat(auto-fit, minmax(340px, 1fr)); }
.grid-4 { grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); }

.card {
  background: var(--coal);
  border: 1px solid rgba(201,162,75,0.15);
  padding: 1.5rem;
  transition: all 0.3s var(--ease-industrial);
  position: relative;
}
.card:hover {
  border-color: var(--gold);
  transform: translateY(-4px);
}
.card::before {
  content: '';
  position: absolute;
  top: 0; left: 0;
  width: 16px; height: 16px;
  border-top: 2px solid var(--gold);
  border-left: 2px solid var(--gold);
}
.card::after {
  content: '';
  position: absolute;
  bottom: 0; right: 0;
  width: 16px; height: 16px;
  border-bottom: 2px solid var(--gold);
  border-right: 2px solid var(--gold);
}

.card-img {
  width: 100%;
  aspect-ratio: 4/3;
  background: var(--steel);
  margin-bottom: 1rem;
  overflow: hidden;
  position: relative;
  display: grid; place-items: center;
}
.card-img img { width: 100%; height: 100%; object-fit: cover; }
.card-img .placeholder-svg { opacity: 0.35; width: 50%; height: 50%; }

.card-title {
  font-family: var(--font-display);
  font-size: 1.2rem;
  text-transform: uppercase;
  color: var(--white-soft);
  margin-bottom: 0.25rem;
}
.card-meta {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--ash);
  letter-spacing: 0.15em;
  text-transform: uppercase;
  margin-bottom: 0.75rem;
}
.card-desc {
  font-size: 0.9rem;
  color: var(--paper-dim);
  margin-bottom: 1rem;
}
.card-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: 1rem;
  padding-top: 1rem;
  border-top: 1px dashed rgba(201,162,75,0.2);
}
.price {
  font-family: var(--font-display);
  font-size: 1.4rem;
  color: var(--gold);
  font-weight: 700;
}
.price small { font-size: 0.7rem; color: var(--ash); }

/* ============================================
   PAGE HEADER (for category pages)
   ============================================ */
.page-header {
  padding: 5rem 0 3rem;
  border-bottom: 1px solid rgba(201,162,75,0.2);
  background:
    linear-gradient(180deg, var(--coal) 0%, var(--matte-black) 100%);
  position: relative;
}
.page-header .breadcrumb {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--ash);
  letter-spacing: 0.2em;
  text-transform: uppercase;
  margin-bottom: 1rem;
}
.page-header .breadcrumb a { color: var(--gold); }
.page-header h1 {
  font-size: clamp(2rem, 5vw, 3.5rem);
}
.page-header h1 .vertex-num {
  color: var(--gold);
  font-size: 0.5em;
  vertical-align: super;
  margin-right: 0.5rem;
  font-family: var(--font-mono);
  letter-spacing: 0;
}
.page-header p.lede {
  max-width: 680px;
  margin-top: 1rem;
  color: var(--paper-dim);
  font-size: 1.05rem;
}

/* ============================================
   CART DRAWER
   ============================================ */
.cart-drawer {
  position: fixed;
  top: 0; right: 0;
  width: min(420px, 100vw);
  height: 100vh;
  background: var(--coal);
  border-left: 2px solid var(--gold);
  z-index: 200;
  transform: translateX(100%);
  transition: transform 0.4s var(--ease-industrial);
  display: flex;
  flex-direction: column;
  box-shadow: -20px 0 60px rgba(0,0,0,0.5);
}
.cart-drawer.open { transform: translateX(0); }

.cart-header {
  padding: 1.5rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  border-bottom: 1px solid rgba(201,162,75,0.2);
}
.cart-header h3 { margin: 0; color: var(--gold); }
.cart-close {
  background: transparent;
  border: 1px solid var(--ash);
  color: var(--paper-dim);
  width: 32px; height: 32px;
  cursor: pointer;
  display: grid; place-items: center;
}
.cart-close:hover { border-color: var(--gold); color: var(--gold); }

.cart-body {
  flex: 1;
  overflow-y: auto;
  padding: 1rem;
}
.cart-empty {
  text-align: center;
  padding: 3rem 1rem;
  color: var(--ash);
  font-family: var(--font-mono);
  font-size: 0.85rem;
}

.cart-item {
  display: grid;
  grid-template-columns: 64px 1fr auto;
  gap: 0.75rem;
  padding: 1rem 0;
  border-bottom: 1px dashed rgba(201,162,75,0.15);
  align-items: center;
}
.cart-item-img {
  width: 64px; height: 64px;
  background: var(--steel);
  display: grid; place-items: center;
}
.cart-item-img svg { width: 60%; height: 60%; opacity: 0.5; }
.cart-item-img img { width: 100%; height: 100%; object-fit: cover; }
.cart-item-name {
  font-family: var(--font-display);
  text-transform: uppercase;
  color: var(--white-soft);
  font-size: 0.9rem;
}
.cart-item-variant {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--ash);
}
.cart-item-price {
  font-family: var(--font-mono);
  color: var(--gold);
  font-size: 0.85rem;
}
.qty-control {
  display: inline-flex;
  border: 1px solid rgba(201,162,75,0.3);
  margin-top: 0.25rem;
}
.qty-control button {
  background: transparent;
  border: none;
  color: var(--gold);
  width: 24px; height: 24px;
  cursor: pointer;
  font-family: var(--font-mono);
}
.qty-control button:hover { background: rgba(201,162,75,0.15); }
.qty-control span {
  width: 28px;
  display: grid; place-items: center;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--white-soft);
}
.cart-item-remove {
  background: transparent;
  border: none;
  color: var(--ash);
  cursor: pointer;
  font-size: 1.1rem;
  align-self: start;
}
.cart-item-remove:hover { color: #e55; }

.cart-footer {
  padding: 1.25rem 1.5rem;
  border-top: 2px solid var(--gold);
  background: var(--matte-black);
}
.cart-total {
  display: flex;
  justify-content: space-between;
  font-family: var(--font-display);
  font-size: 1.4rem;
  text-transform: uppercase;
  margin-bottom: 1rem;
}
.cart-total .v { color: var(--gold); }

.cart-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.65);
  backdrop-filter: blur(4px);
  z-index: 199;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.3s;
}
.cart-backdrop.open { opacity: 1; pointer-events: auto; }

/* ============================================
   TABLES (Tech Specs)
   ============================================ */
.spec-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9rem;
  background: var(--coal);
  border: 1px solid rgba(201,162,75,0.2);
}
.spec-table th, .spec-table td {
  padding: 0.85rem 1rem;
  text-align: left;
  border-bottom: 1px solid rgba(201,162,75,0.1);
}
.spec-table th {
  background: var(--steel);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--gold);
  border-bottom: 2px solid var(--gold);
}
.spec-table tr:hover td { background: rgba(201,162,75,0.04); }
.spec-table td.mono { color: var(--paper-dim); }

/* Badges */
.badge {
  display: inline-block;
  padding: 0.2rem 0.6rem;
  font-family: var(--font-mono);
  font-size: 0.65rem;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  border: 1px solid var(--gold);
  color: var(--gold);
}
.badge.forest { border-color: var(--forest-light); color: var(--forest-light); }
.badge.ok { border-color: #4ea882; color: #4ea882; }
.badge.warn { border-color: #e5a352; color: #e5a352; }

/* Toast */
.toast {
  position: fixed;
  bottom: 2rem;
  left: 50%;
  transform: translateX(-50%) translateY(120%);
  background: var(--gold);
  color: var(--matte-black);
  padding: 0.8rem 1.4rem;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.15em;
  z-index: 300;
  transition: transform 0.3s var(--ease-industrial);
  box-shadow: 0 10px 40px rgba(201,162,75,0.35);
}
.toast.show { transform: translateX(-50%) translateY(0); }

/* ============================================
   FOOTER
   ============================================ */
.site-footer {
  background: var(--coal);
  border-top: 2px solid var(--gold);
  padding: 3rem 0 1.5rem;
  margin-top: 4rem;
  position: relative;
  z-index: 2;
}
.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 2rem;
  margin-bottom: 2rem;
}
.footer-grid h4 {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.2em;
  color: var(--gold);
  margin-bottom: 1rem;
}
.footer-grid ul { list-style: none; }
.footer-grid li { margin: 0.4rem 0; }
.footer-grid a { color: var(--paper-dim); font-size: 0.85rem; }
.footer-grid a:hover { color: var(--gold); }
.footer-bottom {
  border-top: 1px dashed rgba(201,162,75,0.2);
  padding-top: 1.5rem;
  display: flex;
  justify-content: space-between;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--ash);
  letter-spacing: 0.15em;
  text-transform: uppercase;
}

/* ============================================
   FORMS
   ============================================ */
.form-row {
  margin-bottom: 1rem;
}
.form-row label {
  display: block;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--gold);
  margin-bottom: 0.4rem;
}
.form-row input, .form-row select, .form-row textarea {
  width: 100%;
  padding: 0.7rem 0.9rem;
  background: var(--matte-black);
  border: 1px solid rgba(201,162,75,0.25);
  color: var(--paper);
  font-family: var(--font-body);
  font-size: 0.95rem;
  transition: border-color 0.2s;
}
.form-row input:focus, .form-row select:focus, .form-row textarea:focus {
  outline: none;
  border-color: var(--gold);
}
.form-row textarea { min-height: 90px; resize: vertical; }

/* ============================================
   UTILITIES
   ============================================ */
.text-center { text-align: center; }
.text-gold { color: var(--gold); }
.text-dim { color: var(--paper-dim); }
.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }
.mb-4 { margin-bottom: 2rem; }
.mt-4 { margin-top: 2rem; }
.flex { display: flex; gap: 1rem; align-items: center; }
.flex-between { display: flex; justify-content: space-between; align-items: center; }
.flex-wrap { flex-wrap: wrap; }

.divider-pipe {
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--gold), transparent);
  margin: 2rem 0;
}


/* ============================================
   SEVEN-GRID (7-Minute Rule section)
   ============================================ */
.seven-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3rem;
  align-items: center;
}

/* ============================================
   RESPONSIVE
   ============================================ */
@media (max-width: 900px) {
  .nav { display: none; position: absolute; top: 100%; left: 0; right: 0;
    flex-direction: column; background: var(--coal); padding: 1rem;
    border-bottom: 1px solid var(--gold); gap: 0.5rem; align-items: flex-start; }
  .nav.open { display: flex; }
  .nav-toggle { display: inline-flex; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .footer-bottom { flex-direction: column; gap: 0.5rem; text-align: center; }
  .container { padding: 0 1.25rem; }
  .section { padding: 4rem 0; }
  .brand small { display: none; }
  /* Triết lý vận hành: stack 1 column on tablet/mobile */
  .seven-grid { grid-template-columns: 1fr; gap: 2rem; }
}
@media (max-width: 600px) {
  .footer-grid { grid-template-columns: 1fr; }
  .cart-drawer { width: 100vw; }
  .hero-stats { grid-template-columns: repeat(2, 1fr); }
}

/* ============================================
   ANIMATIONS
   ============================================ */
.fade-up {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.8s, transform 0.8s;
}
.fade-up.visible {
  opacity: 1; transform: translateY(0);
}

/* Subtle breathing glow for active core */
@keyframes breathe {
  0%, 100% { filter: drop-shadow(0 0 8px rgba(201,162,75,0.3)); }
  50% { filter: drop-shadow(0 0 20px rgba(201,162,75,0.55)); }
}
.hex-core { animation: breathe 4s ease-in-out infinite; }

.card-list {
  list-style: none;
  padding: 0;
  margin: 0 0 0.75rem 0;
  font-size: 0.9rem;
  color: var(--paper-dim);
}
.card-list li {
  padding: 0.15rem 0;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  letter-spacing: 0.04em;
  color: var(--white-soft);
}

/* ============================================
   HEXAGRAM — MOBILE TUNING
   Bumps vertex bubble + label legibility on phones.
   ============================================ */
@media (max-width: 700px) {
  .hexagram-stage {
    width: min(96vw, 560px);
    margin: 0.5rem auto 1.5rem;
  }
  .hex-vertex text,
  .hex-vertex text.vertex-label-inside {
    font-size: 18px;
    letter-spacing: 0.03em;
  }
  .hex-vertex circle.vertex-bg {
    stroke-width: 2.75;
  }
  .hex-triangle { stroke-width: 1.75; }
}
@media (max-width: 420px) {
  .hexagram-stage { width: 98vw; }
  .hex-vertex text,
  .hex-vertex text.vertex-label-inside {
    font-size: 20px;
  }
}