/* VietAudio - dark hi-fi theme */
:root {
  --bg: #0a0c10;
  --bg-soft: #11141b;
  --card: #151922;
  --card-hover: #1b2029;
  --border: #232a36;
  --text: #e8ecf3;
  --muted: #8b95a7;
  --accent: #ff6b2c;
  --accent-2: #22d3ee;
  --price: #ff8a4c;
  --green: #2ecc71;
  --radius: 14px;
  --shadow: 0 8px 30px rgba(0, 0, 0, .45);
  --max: 1240px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

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

.wrap { max-width: var(--max); margin: 0 auto; padding: 0 20px; }

/* ---------- Header ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(10, 12, 16, .85);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}
.header-inner {
  display: flex;
  align-items: center;
  gap: 24px;
  height: 66px;
}
.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 800;
  font-size: 20px;
  letter-spacing: -.02em;
  white-space: nowrap;
}
.logo-mark {
  width: 32px; height: 32px;
  border-radius: 9px;
  background: linear-gradient(135deg, var(--accent), #ff9d5c);
  display: grid; place-items: center;
  flex: 0 0 auto;
}
.logo-mark svg { width: 18px; height: 18px; }
.logo span.hl { color: var(--accent); }

.nav { display: flex; gap: 4px; margin-left: auto; align-items: center; }
.nav a {
  padding: 8px 14px;
  border-radius: 9px;
  color: var(--muted);
  font-size: 14.5px;
  font-weight: 500;
  transition: .15s;
  white-space: nowrap;
}
.nav a:hover, .nav a.active { color: var(--text); background: var(--card); }

.search-box { position: relative; margin-left: auto; flex: 1; max-width: 340px; }
.search-box input {
  width: 100%;
  background: var(--card);
  border: 1px solid var(--border);
  color: var(--text);
  padding: 9px 14px 9px 38px;
  border-radius: 10px;
  font-size: 14px;
  outline: none;
  transition: .15s;
}
.search-box input:focus { border-color: var(--accent); }
.search-box svg { position: absolute; left: 12px; top: 10px; width: 16px; height: 16px; color: var(--muted); }

.burger {
  display: none;
  background: var(--card); border: 1px solid var(--border);
  color: var(--text); border-radius: 9px; padding: 8px 10px; cursor: pointer;
}

/* ---------- Hero ---------- */
.hero {
  padding: 64px 0 48px;
  background:
    radial-gradient(900px 420px at 15% -10%, rgba(255,107,44,.16), transparent 60%),
    radial-gradient(700px 400px at 90% 0%, rgba(34,211,238,.10), transparent 60%);
  border-bottom: 1px solid var(--border);
}
.hero h1 {
  font-size: clamp(30px, 5vw, 50px);
  line-height: 1.12;
  margin: 0 0 16px;
  letter-spacing: -.03em;
  font-weight: 800;
  max-width: 15ch;
}
.hero h1 .grad {
  background: linear-gradient(100deg, var(--accent), #ffb35c 60%, var(--accent-2));
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.hero p { color: var(--muted); font-size: 17px; max-width: 60ch; margin: 0 0 28px; }
.hero-actions { display: flex; gap: 12px; flex-wrap: wrap; }

.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 12px 22px;
  border-radius: 11px;
  font-weight: 600; font-size: 15px;
  border: 1px solid transparent;
  cursor: pointer;
  transition: .15s;
}
.btn-primary { background: var(--accent); color: #fff; }
.btn-primary:hover { background: #ff7d45; transform: translateY(-1px); }
.btn-ghost { background: var(--card); border-color: var(--border); color: var(--text); }
.btn-ghost:hover { background: var(--card-hover); }

.hero-stats { display: flex; gap: 40px; margin-top: 44px; flex-wrap: wrap; }
.hero-stats div span { display: block; }
.hero-stats .num { font-size: 26px; font-weight: 800; color: var(--text); letter-spacing: -.02em; }
.hero-stats .lbl { font-size: 13.5px; color: var(--muted); }

/* ---------- Sections ---------- */
section { padding: 52px 0; }
.sec-head { display: flex; align-items: flex-end; justify-content: space-between; gap: 20px; margin-bottom: 26px; flex-wrap: wrap; }
.sec-head h2 { font-size: 26px; margin: 0 0 4px; letter-spacing: -.02em; font-weight: 700; }
.sec-head p { margin: 0; color: var(--muted); font-size: 14.5px; }
.sec-head a { color: var(--accent); font-size: 14.5px; font-weight: 600; }

/* ---------- Category cards ---------- */
.cat-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 16px; }
.cat-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  transition: .18s;
  display: block;
}
.cat-card:hover { background: var(--card-hover); border-color: #33405a; transform: translateY(-3px); }
.cat-icon {
  width: 44px; height: 44px; border-radius: 12px;
  background: linear-gradient(135deg, rgba(255,107,44,.2), rgba(34,211,238,.12));
  display: grid; place-items: center; margin-bottom: 14px;
  color: var(--accent);
}
.cat-icon svg { width: 22px; height: 22px; }
.cat-card h3 { margin: 0 0 4px; font-size: 17px; font-weight: 650; }
.cat-card p { margin: 0; color: var(--muted); font-size: 13.5px; }

/* ---------- Product grid ---------- */
.grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(215px, 1fr)); gap: 16px; }

.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  display: flex; flex-direction: column;
  transition: .18s;
  position: relative;
}
.card:hover { border-color: #37455e; transform: translateY(-4px); box-shadow: var(--shadow); }
.card[hidden] { display: none; }

.card-img { position: relative; aspect-ratio: 1/1; background: #0d1016; overflow: hidden; }
.card-img img { width: 100%; height: 100%; object-fit: cover; transition: .35s; }
.card:hover .card-img img { transform: scale(1.05); }

.badge {
  position: absolute; top: 9px; left: 9px;
  background: var(--accent); color: #fff;
  font-size: 11px; font-weight: 700;
  padding: 3px 8px; border-radius: 6px;
  letter-spacing: .01em;
}
.badge.hot { background: #ef4444; }
.badge.comm { left: auto; right: 9px; background: rgba(10,12,16,.82); color: var(--accent-2); border: 1px solid rgba(34,211,238,.3); }

.card-body { padding: 13px 14px 14px; display: flex; flex-direction: column; flex: 1; gap: 8px; }
.card-title {
  font-size: 13.5px; line-height: 1.45; font-weight: 500;
  display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical;
  overflow: hidden; min-height: 2.9em;
  color: #dbe2ec;
}
.card-price { font-size: 19px; font-weight: 800; color: var(--price); letter-spacing: -.02em; }
.card-meta { display: flex; align-items: center; justify-content: space-between; font-size: 12px; color: var(--muted); gap: 8px; }
.card-shop { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.card-sold { flex: 0 0 auto; }
.card-cta {
  margin-top: auto;
  display: flex; align-items: center; justify-content: center; gap: 7px;
  background: linear-gradient(135deg, #ee4d2d, #ff7337);
  color: #fff; font-weight: 650; font-size: 13.5px;
  padding: 9px; border-radius: 9px;
  transition: .15s;
}
.card-cta:hover { filter: brightness(1.1); }
.card-cta svg { width: 15px; height: 15px; }

/* ---------- Filters ---------- */
.filters { display: flex; gap: 10px; flex-wrap: wrap; align-items: center; margin-bottom: 22px; }
.chip {
  background: var(--card); border: 1px solid var(--border); color: var(--muted);
  padding: 7px 15px; border-radius: 999px; font-size: 13.5px; cursor: pointer;
  transition: .15s; font-weight: 500;
}
.chip:hover { color: var(--text); border-color: #38455c; }
.chip.active { background: var(--accent); border-color: var(--accent); color: #fff; }
.select {
  background: var(--card); border: 1px solid var(--border); color: var(--text);
  padding: 7px 12px; border-radius: 9px; font-size: 13.5px; outline: none; cursor: pointer;
}
.filters .spacer { margin-left: auto; }
.result-count { color: var(--muted); font-size: 14px; margin-bottom: 16px; }

.empty { text-align: center; padding: 60px 20px; color: var(--muted); }

/* ---------- Disclosure ---------- */
.notice {
  background: linear-gradient(135deg, rgba(255,107,44,.08), rgba(34,211,238,.05));
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px 22px;
  color: var(--muted);
  font-size: 14px;
  display: flex; gap: 14px; align-items: flex-start;
}
.notice svg { width: 20px; height: 20px; flex: 0 0 auto; color: var(--accent); margin-top: 2px; }
.notice strong { color: var(--text); }

/* ---------- Article / prose ---------- */
.prose { max-width: 76ch; }
.prose h2 { font-size: 22px; margin: 34px 0 12px; letter-spacing: -.02em; }
.prose h3 { font-size: 17px; margin: 26px 0 8px; }
.prose p, .prose li { color: #bcc5d3; font-size: 15.5px; }
.prose ul { padding-left: 20px; }
.prose a { color: var(--accent-2); text-decoration: underline; text-underline-offset: 3px; }

/* ---------- Footer ---------- */
.site-footer { border-top: 1px solid var(--border); background: var(--bg-soft); padding: 46px 0 30px; margin-top: 40px; }
.footer-grid { display: grid; grid-template-columns: 1.6fr 1fr 1fr 1fr; gap: 34px; }
.footer-grid h4 { font-size: 14px; margin: 0 0 12px; color: var(--text); font-weight: 650; }
.footer-grid ul { list-style: none; padding: 0; margin: 0; display: grid; gap: 8px; }
.footer-grid a, .footer-grid li { color: var(--muted); font-size: 14px; }
.footer-grid a:hover { color: var(--accent); }
.footer-about p { color: var(--muted); font-size: 14px; margin: 12px 0 0; max-width: 42ch; }
.footer-bottom {
  margin-top: 34px; padding-top: 22px; border-top: 1px solid var(--border);
  color: var(--muted); font-size: 13px;
  display: flex; justify-content: space-between; gap: 16px; flex-wrap: wrap;
}

/* ---------- Responsive ---------- */
@media (max-width: 900px) {
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .nav { display: none; }
  .nav.open {
    display: flex; flex-direction: column; align-items: stretch;
    position: absolute; top: 66px; left: 0; right: 0;
    background: var(--bg-soft); border-bottom: 1px solid var(--border);
    padding: 10px 20px 16px; gap: 2px;
  }
  .burger { display: block; order: 3; }
  .search-box { max-width: none; }
}
@media (max-width: 560px) {
  .grid { grid-template-columns: repeat(auto-fill, minmax(158px, 1fr)); gap: 12px; }
  .card-title { font-size: 12.5px; }
  .card-price { font-size: 16.5px; }
  .footer-grid { grid-template-columns: 1fr; gap: 26px; }
  .hero { padding: 44px 0 36px; }
  .hero-stats { gap: 26px; }
  section { padding: 40px 0; }
}