/* core/ui/base.css
 * Structural styles for the engine — shared by every shop, linked BEFORE the shop's theme.css.
 * Uses design tokens only (var(--…)): ZERO literal colours/fonts/brand values (brief §5).
 * Shops restyle entirely by overriding tokens in theme.css. */

*, *::before, *::after { box-sizing: border-box; }
* { margin: 0; }
img, svg { display: block; max-width: 100%; }

body {
  background: var(--color-bg);
  color: var(--color-fg);
  font-family: var(--font-body);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  min-height: 100vh;
}

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

:where(a, button, input, textarea):focus-visible {
  outline: 2px solid var(--ring);
  outline-offset: 2px;
  border-radius: var(--radius);
}

/* ---- layout ---- */
.site-header,
.site-main,
.site-footer { max-width: var(--maxw); margin-inline: auto; padding-inline: var(--space-3); }

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-2);
  padding-block: var(--space-2);
  background: color-mix(in srgb, var(--color-bg) 88%, transparent);
  backdrop-filter: saturate(1.4) blur(8px);
  border-bottom: 1px solid var(--color-border);
}
.site-main { padding-block: var(--space-4) var(--space-5); min-height: 70vh; }
.site-footer {
  padding-block: var(--space-3);
  margin-top: var(--space-5);
  border-top: 1px solid var(--color-border);
  color: var(--color-muted);
  font-size: 0.875rem;
}

.brand { display: inline-flex; align-items: center; gap: var(--space-1); }
.brand-logo { height: 34px; width: 34px; border-radius: var(--radius); }
.brand-name { font-family: var(--font-heading); font-weight: 700; font-size: 1.2rem; letter-spacing: -0.01em; }
.site-nav { display: flex; gap: var(--space-3); align-items: center; }
.nav-link { font-weight: 600; color: var(--color-accent); }
.nav-link:hover { text-decoration: underline; text-underline-offset: 4px; }

.page-title {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: clamp(1.6rem, 1.1rem + 2vw, 2.4rem);
  letter-spacing: -0.02em;
  line-height: 1.15;
  margin-bottom: var(--space-4);
}

/* ---- catalog ---- */
.catalog-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(230px, 1fr));
  gap: var(--space-3);
}
.card {
  display: flex;
  flex-direction: column;
  background: var(--color-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  transition: transform 0.18s ease, box-shadow 0.18s ease, border-color 0.18s ease;
}
.card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
  border-color: color-mix(in srgb, var(--color-accent) 45%, var(--color-border));
}
.card-img { width: 100%; aspect-ratio: 4 / 3; object-fit: cover; background: var(--color-border); transition: transform 0.3s ease; }
.card:hover .card-img { transform: scale(1.04); }
.card-img.placeholder {
  background: repeating-linear-gradient(45deg, var(--color-border), var(--color-border) 12px,
    color-mix(in srgb, var(--color-border) 60%, var(--color-bg)) 12px, color-mix(in srgb, var(--color-border) 60%, var(--color-bg)) 24px);
}
.card-body { display: flex; flex-direction: column; gap: 0.25rem; padding: var(--space-2); }
.card-title { font-weight: 600; line-height: 1.3; }
.card-price { color: var(--color-accent); font-weight: 700; font-variant-numeric: tabular-nums; }

/* ---- listing detail ---- */
.detail { display: grid; gap: var(--space-4); }
@media (min-width: 760px) {
  .detail { grid-template-columns: 1.1fr 1fr; align-items: start; }
  .detail > .back { grid-column: 1 / -1; }
}
.back { display: inline-flex; align-items: center; gap: 0.35rem; color: var(--color-muted); font-weight: 500; }
.back:hover { color: var(--color-accent); }
.detail-gallery { display: flex; flex-direction: column; gap: var(--space-2); }
.detail-img { width: 100%; border-radius: var(--radius-lg); border: 1px solid var(--color-border); }
.detail-img.placeholder {
  aspect-ratio: 4 / 3;
  background: repeating-linear-gradient(45deg, var(--color-border), var(--color-border) 14px,
    color-mix(in srgb, var(--color-border) 60%, var(--color-bg)) 14px, color-mix(in srgb, var(--color-border) 60%, var(--color-bg)) 28px);
}
.detail-info { display: flex; flex-direction: column; gap: var(--space-2); }
.detail-title { font-family: var(--font-heading); font-weight: 700; font-size: clamp(1.6rem, 1.2rem + 1.6vw, 2.3rem); line-height: 1.15; letter-spacing: -0.02em; }
.detail-price { color: var(--color-accent); font-size: 1.6rem; font-weight: 700; font-variant-numeric: tabular-nums; }
.detail-desc { white-space: pre-wrap; color: color-mix(in srgb, var(--color-fg) 85%, var(--color-bg)); }
.detail-stock {
  align-self: flex-start;
  font-size: 0.8rem; font-weight: 600; color: var(--color-accent);
  background: color-mix(in srgb, var(--color-accent) 12%, var(--color-bg));
  padding: 0.25rem 0.6rem; border-radius: 999px;
}

/* ---- buttons ---- */
.btn-buy {
  align-self: flex-start;
  margin-top: var(--space-1);
  padding: 0.8rem 1.6rem;
  font: inherit;
  font-family: var(--font-heading);
  font-weight: 700;
  color: var(--color-accent-contrast);
  background: var(--color-accent);
  border: 0;
  border-radius: var(--radius-lg);
  cursor: pointer;
  box-shadow: var(--shadow-sm);
  transition: filter 0.15s ease, transform 0.1s ease, box-shadow 0.15s ease;
}
.btn-buy:hover { filter: brightness(0.93); box-shadow: var(--shadow-md); }
.btn-buy:active { transform: translateY(1px); }
.btn-buy:disabled { opacity: 0.55; cursor: default; filter: none; box-shadow: none; }

/* ---- sell form ---- */
.sell-form { max-width: 560px; display: flex; flex-direction: column; gap: var(--space-2); }
.field { display: flex; flex-direction: column; gap: 0.4rem; }
.field-label { font-family: var(--font-heading); font-size: 0.85rem; font-weight: 600; color: var(--color-muted); }
.field input, .field textarea {
  font: inherit;
  padding: 0.65rem 0.8rem;
  color: var(--color-fg);
  background: var(--color-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  transition: border-color 0.15s ease, box-shadow 0.15s ease;
}
.field input:focus, .field textarea:focus {
  outline: none;
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--color-accent) 22%, transparent);
}
.field textarea { resize: vertical; min-height: 6rem; }
.form-msg { min-height: 1.3em; font-size: 0.9rem; color: var(--color-muted); }
.form-msg.ok { color: var(--color-accent); }
.form-msg.error, .error { color: var(--color-error); }

/* ---- receipt + states ---- */
.receipt { max-width: 560px; }
.confirm {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  background: var(--color-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  padding: var(--space-4);
}
.confirm .page-title { margin: 0; }
.confirm-badge {
  align-self: flex-start;
  font-size: 0.8rem; font-weight: 700; letter-spacing: 0.02em;
  color: var(--color-muted);
  background: color-mix(in srgb, var(--color-muted) 14%, var(--color-bg));
  padding: 0.3rem 0.7rem; border-radius: 999px;
}
.confirm-badge.ok {
  color: var(--color-accent);
  background: color-mix(in srgb, var(--color-accent) 14%, var(--color-bg));
}
.confirm-item {
  display: flex; gap: var(--space-2); align-items: center;
  padding: var(--space-2);
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
}
.confirm-thumb { width: 72px; height: 72px; object-fit: cover; border-radius: var(--radius); flex: none; background: var(--color-border); }
.confirm-thumb.placeholder {
  background: repeating-linear-gradient(45deg, var(--color-border), var(--color-border) 8px,
    color-mix(in srgb, var(--color-border) 60%, var(--color-bg)) 8px, color-mix(in srgb, var(--color-border) 60%, var(--color-bg)) 16px);
}
.confirm-item-text { display: flex; flex-direction: column; gap: 0.2rem; }
.confirm-item-title { font-weight: 600; }
.confirm-item-price { color: var(--color-accent); font-weight: 700; font-variant-numeric: tabular-nums; }
.confirm-ref { font-size: 0.8rem; word-break: break-all; }
.muted { color: var(--color-muted); }
.empty, .error, .loading {
  grid-column: 1 / -1;
  text-align: center;
  color: var(--color-muted);
  padding: var(--space-5) var(--space-2);
  font-size: 1.05rem;
}

@media (prefers-reduced-motion: reduce) {
  * { transition: none !important; animation: none !important; }
  .card:hover { transform: none; }
  .card:hover .card-img { transform: none; }
}