/* ==========================================================================
   KaizZ Shop — Giao diện cửa hàng số (Mobile-First, Tối giản, Hiện đại)
   ========================================================================== */

:root {
  --color-bg-base: #0a0e17;
  --color-bg-surface: #111827;
  --color-bg-surface-hover: #1f293d;
  --color-bg-card: #151d30;
  --color-bg-card-hover: #1a243d;
  --color-bg-muted: #1e293b;

  --color-border-subtle: #243048;
  --color-border-focus: #6366f1;

  --color-text-main: #f9fafb;
  --color-text-secondary: #94a3b8;
  --color-text-muted: #64748b;

  --color-primary: #4f46e5;
  --color-primary-hover: #4338ca;
  --color-primary-light: #e0e7ff;
  --color-primary-ring: rgba(99, 102, 241, 0.4);

  --color-success: #10b981;
  --color-success-bg: rgba(16, 185, 129, 0.12);
  --color-success-border: rgba(16, 185, 129, 0.3);

  --color-warning: #f59e0b;
  --color-warning-bg: rgba(245, 158, 11, 0.12);
  --color-warning-border: rgba(245, 158, 11, 0.3);

  --color-danger: #ef4444;
  --color-danger-bg: rgba(239, 68, 68, 0.12);
  --color-danger-border: rgba(239, 68, 68, 0.3);

  --font-family-base: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji';
  --font-family-mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;

  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --radius-pill: 9999px;

  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 10px 25px -5px rgba(0, 0, 0, 0.5);

  --container-max-width: 1160px;
}

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

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

body {
  font-family: var(--font-family-base);
  background-color: var(--color-bg-base);
  color: var(--color-text-main);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  -webkit-font-smoothing: antialiased;
}

/* Accessibility: Skip Link */
.skip-link {
  position: absolute;
  top: -50px;
  left: 16px;
  background: var(--color-primary);
  color: #fff;
  padding: 8px 16px;
  border-radius: var(--radius-sm);
  z-index: 1000;
  font-weight: 600;
  text-decoration: none;
  transition: top 0.2s ease;
}

.skip-link:focus {
  top: 16px;
}

/* Focus outlines */
:focus-visible {
  outline: 2px solid var(--color-border-focus);
  outline-offset: 2px;
}

/* Layout Container */
.container {
  width: 100%;
  max-width: var(--container-max-width);
  margin-left: auto;
  margin-right: auto;
  padding-left: 20px;
  padding-right: 20px;
}

/* Header */
.site-header {
  background: linear-gradient(180deg, #111827 0%, #0d1321 100%);
  border-bottom: 1px solid var(--color-border-subtle);
  padding: 24px 0 20px;
}

.header-inner {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.brand-wrapper {
  display: flex;
  align-items: center;
  gap: 14px;
}

.brand-logo-badge {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  background: linear-gradient(135deg, #4f46e5 0%, #7c3aed 100%);
  color: #fff;
  border-radius: var(--radius-md);
  font-weight: 800;
  font-size: 1.25rem;
  box-shadow: 0 4px 12px rgba(79, 70, 229, 0.35);
  flex-shrink: 0;
}

.brand-info {
  display: flex;
  flex-direction: column;
}

.brand-title {
  font-size: 1.6rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--color-text-main);
  line-height: 1.2;
}

.brand-subtitle {
  font-size: 0.9rem;
  color: var(--color-text-secondary);
  margin-top: 2px;
}

/* System Notice Banner */
.status-banner {
  display: flex;
  align-items: center;
  gap: 10px;
  background: var(--color-warning-bg);
  border: 1px solid var(--color-warning-border);
  color: #fcd34d;
  padding: 10px 14px;
  border-radius: var(--radius-md);
  font-size: 0.875rem;
  font-weight: 500;
}

.status-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background-color: var(--color-warning);
  flex-shrink: 0;
  animation: pulse-dot 2s infinite ease-in-out;
}

@keyframes pulse-dot {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.4; transform: scale(0.85); }
}

/* Main Content Area */
.main-content {
  flex: 1;
  padding: 32px 0 48px;
}

/* Controls Section */
.controls-card {
  background-color: var(--color-bg-surface);
  border: 1px solid var(--color-border-subtle);
  border-radius: var(--radius-lg);
  padding: 20px;
  margin-bottom: 24px;
  box-shadow: var(--shadow-sm);
}

.controls-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 12px;
}

@media (min-width: 640px) {
  .controls-grid {
    grid-template-columns: 2fr 1fr 1fr auto;
    align-items: center;
  }
}

.input-group {
  position: relative;
  display: flex;
  align-items: center;
}

.search-input {
  width: 100%;
  height: 42px;
  background-color: var(--color-bg-base);
  border: 1px solid var(--color-border-subtle);
  border-radius: var(--radius-md);
  padding: 0 14px 0 38px;
  color: var(--color-text-main);
  font-size: 0.925rem;
  font-family: inherit;
  transition: border-color 0.15s ease, box-shadow 0.15s ease;
}

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

.search-input:focus {
  border-color: var(--color-border-focus);
  box-shadow: 0 0 0 3px var(--color-primary-ring);
  outline: none;
}

.search-icon {
  position: absolute;
  left: 12px;
  width: 16px;
  height: 16px;
  color: var(--color-text-muted);
  pointer-events: none;
}

.select-filter {
  height: 42px;
  background-color: var(--color-bg-base);
  border: 1px solid var(--color-border-subtle);
  border-radius: var(--radius-md);
  padding: 0 12px;
  color: var(--color-text-main);
  font-size: 0.9rem;
  font-family: inherit;
  cursor: pointer;
  transition: border-color 0.15s ease;
}

.select-filter:focus {
  border-color: var(--color-border-focus);
  box-shadow: 0 0 0 3px var(--color-primary-ring);
  outline: none;
}

/* Button Component */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  height: 42px;
  padding: 0 16px;
  border-radius: var(--radius-md);
  font-size: 0.9rem;
  font-weight: 600;
  font-family: inherit;
  cursor: pointer;
  border: 1px solid transparent;
  transition: background-color 0.15s ease, border-color 0.15s ease, transform 0.1s ease;
  white-space: nowrap;
}

.btn:active {
  transform: scale(0.98);
}

.btn-secondary {
  background-color: var(--color-bg-muted);
  color: var(--color-text-main);
  border-color: var(--color-border-subtle);
}

.btn-secondary:hover {
  background-color: var(--color-bg-surface-hover);
  border-color: var(--color-text-muted);
}

.btn-primary {
  background-color: var(--color-primary);
  color: #fff;
}

.btn-primary:hover {
  background-color: var(--color-primary-hover);
}

.btn-disabled {
  background-color: var(--color-bg-muted);
  color: var(--color-text-muted);
  border-color: var(--color-border-subtle);
  cursor: not-allowed;
  opacity: 0.75;
}

.btn-disabled:active {
  transform: none;
}

/* Summary Bar */
.catalog-meta-bar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 20px;
  padding: 0 4px;
}

.results-count {
  font-size: 0.9rem;
  color: var(--color-text-secondary);
}

.results-count strong {
  color: var(--color-text-main);
}

.badge-tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 10px;
  border-radius: var(--radius-pill);
  font-size: 0.775rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.badge-tag-warning {
  background-color: var(--color-warning-bg);
  border: 1px solid var(--color-warning-border);
  color: #fbbf24;
}

/* Product Cards Grid */
.products-grid {
  list-style: none;
  display: grid;
  grid-template-columns: 1fr;
  gap: 20px;
}

@media (min-width: 640px) {
  .products-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 1024px) {
  .products-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

/* Product Card */
.product-card {
  background-color: var(--color-bg-card);
  border: 1px solid var(--color-border-subtle);
  border-radius: var(--radius-lg);
  padding: 24px;
  display: flex;
  flex-direction: column;
  transition: transform 0.2s ease, border-color 0.2s ease, box-shadow 0.2s ease;
  position: relative;
}

.product-card:hover {
  transform: translateY(-2px);
  border-color: #3b4d75;
  box-shadow: var(--shadow-md);
}

.card-top {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 16px;
}

.product-emoji {
  width: 52px;
  height: 52px;
  border-radius: var(--radius-md);
  background-color: var(--color-bg-surface);
  border: 1px solid var(--color-border-subtle);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.8rem;
  flex-shrink: 0;
  user-select: none;
}

.stock-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 10px;
  border-radius: var(--radius-pill);
  font-size: 0.8rem;
  font-weight: 600;
}

.stock-badge.in-stock {
  background-color: var(--color-success-bg);
  border: 1px solid var(--color-success-border);
  color: #34d399;
}

.stock-badge.out-of-stock {
  background-color: var(--color-danger-bg);
  border: 1px solid var(--color-danger-border);
  color: #f87171;
}

.card-body {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-bottom: 20px;
}

.product-title {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--color-text-main);
  line-height: 1.35;
  word-break: break-word;
}

.product-desc {
  font-size: 0.88rem;
  color: var(--color-text-secondary);
  line-height: 1.5;
  word-break: break-word;
}

.card-footer {
  border-top: 1px solid var(--color-border-subtle);
  padding-top: 16px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.price-row {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
}

.price-label {
  font-size: 0.8rem;
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  font-weight: 600;
}

.price-value {
  font-size: 1.3rem;
  font-weight: 700;
  color: #a5b4fc;
  font-family: var(--font-family-mono);
}

.card-action-box {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.action-caption {
  font-size: 0.75rem;
  color: var(--color-text-muted);
  text-align: center;
}

/* Empty, Error & Unconfigured States */
.state-container {
  background-color: var(--color-bg-card);
  border: 1px solid var(--color-border-subtle);
  border-radius: var(--radius-lg);
  padding: 48px 24px;
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 16px;
  max-width: 600px;
  margin: 32px auto;
  box-shadow: var(--shadow-sm);
}

.state-icon-box {
  width: 64px;
  height: 64px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2rem;
  background-color: var(--color-bg-surface);
  border: 1px solid var(--color-border-subtle);
}

.state-title {
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--color-text-main);
}

.state-message {
  font-size: 0.95rem;
  color: var(--color-text-secondary);
  line-height: 1.6;
  max-width: 480px;
}

.state-tip {
  font-size: 0.825rem;
  color: var(--color-text-muted);
  background-color: var(--color-bg-surface);
  padding: 8px 16px;
  border-radius: var(--radius-sm);
  border: 1px dashed var(--color-border-subtle);
  font-family: var(--font-family-mono);
  word-break: break-all;
}

/* Skeleton Loading */
.skeleton-card {
  background-color: var(--color-bg-card);
  border: 1px solid var(--color-border-subtle);
  border-radius: var(--radius-lg);
  padding: 24px;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.skeleton-box {
  background: linear-gradient(90deg, #182236 25%, #22304d 50%, #182236 75%);
  background-size: 200% 100%;
  animation: shimmer 1.5s infinite linear;
  border-radius: var(--radius-sm);
}

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

/* Footer */
.site-footer {
  margin-top: auto;
  background-color: var(--color-bg-surface);
  border-top: 1px solid var(--color-border-subtle);
  padding: 40px 0 28px;
  color: var(--color-text-secondary);
  font-size: 0.875rem;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 28px;
  margin-bottom: 32px;
}

@media (min-width: 768px) {
  .footer-grid {
    grid-template-columns: 2fr 1fr 1fr;
  }
}

.footer-col-title {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--color-text-main);
  margin-bottom: 10px;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.footer-text {
  line-height: 1.6;
  color: var(--color-text-secondary);
}

.footer-bottom {
  border-top: 1px solid var(--color-border-subtle);
  padding-top: 20px;
  text-align: center;
  font-size: 0.8rem;
  color: var(--color-text-muted);
}