/*
 * SUPERNATURAL Design Language
 *
 * Inspired by Red Hat Design Language (https://ux.redhat.com/)
 * Licensed under MIT. Custom --sn-* namespace with Supernatural colorway.
 *
 * Structure:
 *   1. Font faces
 *   2. Design tokens (CSS custom properties)
 *   3. CSS reset
 *   4. Base typography
 *   5. Component classes
 *   6. Layout utilities
 *   7. Responsive adjustments
 *   8. Base layout (marketplace)
 *   9. Admin layout
 *  10. Legacy compatibility
 */

/* ==========================================================================
   1. FONT FACES
   ========================================================================== */

@font-face {
  font-family: 'Red Hat Display';
  src: url('/static/fonts/RedHatDisplay-Variable.woff2') format('woff2');
  font-weight: 300 900;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: 'Red Hat Display';
  src: url('/static/fonts/RedHatDisplay-Italic-Variable.woff2') format('woff2');
  font-weight: 300 900;
  font-style: italic;
  font-display: swap;
}

@font-face {
  font-family: 'Red Hat Text';
  src: url('/static/fonts/RedHatText-Variable.woff2') format('woff2');
  font-weight: 300 700;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: 'Red Hat Text';
  src: url('/static/fonts/RedHatText-Italic-Variable.woff2') format('woff2');
  font-weight: 300 700;
  font-style: italic;
  font-display: swap;
}

@font-face {
  font-family: 'Red Hat Mono';
  src: url('/static/fonts/RedHatMono-Variable.woff2') format('woff2');
  font-weight: 300 700;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: 'Red Hat Mono';
  src: url('/static/fonts/RedHatMono-Italic-Variable.woff2') format('woff2');
  font-weight: 300 700;
  font-style: italic;
  font-display: swap;
}

/* ==========================================================================
   2. DESIGN TOKENS
   ========================================================================== */

:root {
  /* Force light mode initially. To enable dark mode later,
     change to: color-scheme: light dark; */
  color-scheme: light;

  /* --- Colors --- */

  /* Brand */
  --sn-color-brand-primary: light-dark(#2d3436, #e0e0e0);
  --sn-color-brand-accent: light-dark(#00b894, #00d4aa);

  /* Surface */
  --sn-color-surface-default: light-dark(#ffffff, #1a1a2e);
  --sn-color-surface-secondary: light-dark(#f8f9fa, #16213e);
  --sn-color-surface-tertiary: light-dark(#f0f0f0, #1e2a4a);
  --sn-color-surface-raised: light-dark(#ffffff, #222244);

  /* Text */
  --sn-color-text-primary: light-dark(#2d3436, #e0e0e0);
  --sn-color-text-secondary: light-dark(#636e72, #a0a0a0);
  --sn-color-text-muted: light-dark(#999999, #666666);
  --sn-color-text-on-dark: #ffffff;
  --sn-color-text-on-accent: #ffffff;

  /* Border */
  --sn-color-border-default: light-dark(#dfe6e9, #2a2a4a);
  --sn-color-border-subtle: light-dark(#e9ecef, #222244);
  --sn-color-border-strong: light-dark(#b2bec3, #444466);

  /* Interactive */
  --sn-color-interactive-default: light-dark(#00b894, #00d4aa);
  --sn-color-interactive-hover: light-dark(#00a884, #00e4ba);
  --sn-color-interactive-focus: light-dark(#00b894, #00d4aa);
  --sn-color-interactive-secondary: light-dark(#2d3436, #e0e0e0);
  --sn-color-interactive-secondary-hover: light-dark(#1e2526, #f0f0f0);

  /* Status */
  --sn-color-status-success: light-dark(#00b894, #00d4aa);
  --sn-color-status-danger: light-dark(#d63031, #ff6b6b);
  --sn-color-status-danger-hover: light-dark(#c0392b, #ff5252);
  --sn-color-status-warning: light-dark(#fdcb6e, #fdcb6e);
  --sn-color-status-warning-hover: light-dark(#f9c03a, #f9c03a);
  --sn-color-status-info: light-dark(#0984e3, #74b9ff);

  /* Status backgrounds (transparent tints for alerts, messages) */
  --sn-color-status-success-bg: rgba(0, 184, 148, 0.08);
  --sn-color-status-danger-bg: rgba(214, 48, 49, 0.08);
  --sn-color-status-warning-bg: rgba(253, 203, 110, 0.15);
  --sn-color-status-info-bg: rgba(9, 132, 227, 0.08);

  /* Interactive surface tints */
  --sn-color-interactive-tint: rgba(0, 184, 148, 0.08);
  --sn-color-interactive-tint-active: rgba(0, 184, 148, 0.2);

  /* On-dark surface colors (for dark backgrounds like header, sidebar, footer) */
  --sn-color-on-dark-primary: rgba(255, 255, 255, 0.8);
  --sn-color-on-dark-secondary: rgba(255, 255, 255, 0.6);
  --sn-color-on-dark-muted: rgba(255, 255, 255, 0.5);
  --sn-color-on-dark-border: rgba(255, 255, 255, 0.2);
  --sn-color-on-dark-hover: rgba(255, 255, 255, 0.1);

  /* Domain-specific: Fiber tiers */
  --sn-color-fiber-pure: light-dark(#00b894, #00d4aa);
  --sn-color-fiber-majority: light-dark(#0984e3, #74b9ff);
  --sn-color-fiber-blend: light-dark(#6c5ce7, #a29bfe);
  --sn-color-fiber-mended: light-dark(#fdcb6e, #fdcb6e);

  /* --- Spacing (4px grid) --- */
  --sn-space-xs: 0.25rem;   /*  4px */
  --sn-space-sm: 0.5rem;    /*  8px */
  --sn-space-md: 1rem;      /* 16px */
  --sn-space-lg: 1.5rem;    /* 24px */
  --sn-space-xl: 2rem;      /* 32px */
  --sn-space-2xl: 3rem;     /* 48px */
  --sn-space-3xl: 4rem;     /* 64px */

  /* --- Typography --- */
  --sn-font-family-heading: 'Red Hat Display', system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --sn-font-family-body: 'Red Hat Text', system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --sn-font-family-mono: 'Red Hat Mono', ui-monospace, 'Cascadia Code', 'Fira Code', monospace;

  --sn-font-size-xs: 0.75rem;    /* 12px */
  --sn-font-size-sm: 0.875rem;   /* 14px */
  --sn-font-size-md: 1rem;       /* 16px */
  --sn-font-size-lg: 1.125rem;   /* 18px */
  --sn-font-size-xl: 1.25rem;    /* 20px */
  --sn-font-size-2xl: 1.5rem;    /* 24px */
  --sn-font-size-3xl: 2rem;      /* 32px */
  --sn-font-size-4xl: 2.5rem;    /* 40px */

  --sn-font-weight-regular: 400;
  --sn-font-weight-medium: 500;
  --sn-font-weight-semibold: 600;
  --sn-font-weight-bold: 700;

  --sn-line-height-tight: 1.3;
  --sn-line-height-normal: 1.5;
  --sn-line-height-relaxed: 1.7;

  /* --- Borders & Radii --- */
  --sn-border-radius-sm: 3px;
  --sn-border-radius-md: 6px;
  --sn-border-radius-lg: 12px;
  --sn-border-radius-pill: 999px;

  --sn-border-width-sm: 1px;
  --sn-border-width-md: 2px;

  /* --- Shadows --- */
  --sn-shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
  --sn-shadow-md: 0 4px 6px rgba(0, 0, 0, 0.07);
  --sn-shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.1);
  --sn-shadow-focus: 0 0 0 3px rgba(0, 184, 148, 0.15);
  --sn-shadow-focus-danger: 0 0 0 3px rgba(214, 48, 49, 0.15);

  /* --- Layout --- */
  --sn-admin-sidebar-width: 240px;
  --sn-admin-sidebar-width-collapsed: 60px;

  /* --- Breakpoints (reference values — cannot be used in @media directly) --- */
  --sn-breakpoint-sm: 576px;
  --sn-breakpoint-md: 768px;
  --sn-breakpoint-lg: 992px;
  --sn-breakpoint-xl: 1200px;

  /* --- Transitions --- */
  --sn-transition-fast: 0.15s ease;
  --sn-transition-normal: 0.2s ease;
}

/* ==========================================================================
   3. CSS RESET
   ========================================================================== */

*,
*::before,
*::after {
  box-sizing: border-box;
}

* {
  margin: 0;
  padding: 0;
}

html {
  -webkit-text-size-adjust: 100%;
  -moz-text-size-adjust: 100%;
  text-size-adjust: 100%;
}

input, button, textarea, select {
  font: inherit;
}

button {
  cursor: pointer;
}

table {
  border-collapse: collapse;
}

/* ==========================================================================
   4. BASE TYPOGRAPHY
   ========================================================================== */

body {
  font-family: var(--sn-font-family-body);
  font-size: var(--sn-font-size-md);
  font-weight: var(--sn-font-weight-regular);
  line-height: var(--sn-line-height-relaxed);
  color: var(--sn-color-text-primary);
  background: var(--sn-color-surface-default);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--sn-font-family-heading);
  font-weight: var(--sn-font-weight-bold);
  line-height: var(--sn-line-height-tight);
  color: var(--sn-color-text-primary);
}

h1 { font-size: var(--sn-font-size-3xl); }
h2 { font-size: var(--sn-font-size-2xl); }
h3 { font-size: var(--sn-font-size-xl); }
h4 { font-size: var(--sn-font-size-lg); }
h5 { font-size: var(--sn-font-size-md); }
h6 { font-size: var(--sn-font-size-sm); }

p {
  margin-bottom: var(--sn-space-md);
}

p:last-child {
  margin-bottom: 0;
}

small {
  font-size: var(--sn-font-size-sm);
}

code, pre {
  font-family: var(--sn-font-family-mono);
  font-size: var(--sn-font-size-sm);
}

/* ==========================================================================
   5. COMPONENT CLASSES
   ========================================================================== */

/* --- Buttons --- */

.sn-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--sn-space-sm);
  padding: var(--sn-space-sm) var(--sn-space-md);
  font-family: var(--sn-font-family-body);
  font-size: var(--sn-font-size-sm);
  font-weight: var(--sn-font-weight-medium);
  line-height: 1;
  border: var(--sn-border-width-sm) solid transparent;
  border-radius: var(--sn-border-radius-md);
  cursor: pointer;
  transition: background-color var(--sn-transition-fast),
              border-color var(--sn-transition-fast),
              transform var(--sn-transition-fast);
  text-decoration: none;
  white-space: nowrap;
}

.sn-btn:focus-visible {
  outline: var(--sn-border-width-md) solid var(--sn-color-interactive-focus);
  outline-offset: 2px;
}

.sn-btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.sn-btn--primary {
  background: var(--sn-color-interactive-default);
  color: var(--sn-color-text-on-accent);
  border-color: var(--sn-color-interactive-default);
}
.sn-btn--primary:hover:not(:disabled) {
  background: var(--sn-color-interactive-hover);
  border-color: var(--sn-color-interactive-hover);
}

.sn-btn--secondary {
  background: transparent;
  color: var(--sn-color-text-primary);
  border-color: var(--sn-color-border-default);
}
.sn-btn--secondary:hover:not(:disabled) {
  border-color: var(--sn-color-border-strong);
  background: var(--sn-color-surface-secondary);
}

.sn-btn--dark {
  background: var(--sn-color-interactive-secondary);
  color: var(--sn-color-text-on-dark);
  border-color: var(--sn-color-interactive-secondary);
}
.sn-btn--dark:hover:not(:disabled) {
  background: var(--sn-color-interactive-secondary-hover);
}

.sn-btn--danger {
  background: var(--sn-color-status-danger);
  color: var(--sn-color-text-on-accent);
  border-color: var(--sn-color-status-danger);
}
.sn-btn--danger:hover:not(:disabled) {
  background: var(--sn-color-status-danger-hover);
  border-color: var(--sn-color-status-danger-hover);
}

.sn-btn--warning {
  background: var(--sn-color-status-warning);
  color: var(--sn-color-text-primary);
  border-color: var(--sn-color-status-warning);
}
.sn-btn--warning:hover:not(:disabled) {
  background: var(--sn-color-status-warning-hover);
  border-color: var(--sn-color-status-warning-hover);
}

.sn-btn--ghost {
  background: transparent;
  color: var(--sn-color-interactive-default);
  border-color: transparent;
}
.sn-btn--ghost:hover:not(:disabled) {
  background: var(--sn-color-interactive-tint);
}

.sn-btn--sm {
  padding: var(--sn-space-xs) var(--sn-space-sm);
  font-size: var(--sn-font-size-xs);
}

.sn-btn--lg {
  padding: var(--sn-space-md) var(--sn-space-lg);
  font-size: var(--sn-font-size-md);
}

/* --- Cards --- */

.sn-card {
  background: var(--sn-color-surface-raised);
  border: var(--sn-border-width-sm) solid var(--sn-color-border-subtle);
  border-radius: var(--sn-border-radius-lg);
  box-shadow: var(--sn-shadow-sm);
  overflow: hidden;
}

.sn-card__header {
  padding: var(--sn-space-md);
  border-bottom: var(--sn-border-width-sm) solid var(--sn-color-border-subtle);
  font-weight: var(--sn-font-weight-semibold);
}

.sn-card__body {
  padding: var(--sn-space-md);
}

.sn-card__footer {
  padding: var(--sn-space-md);
  border-top: var(--sn-border-width-sm) solid var(--sn-color-border-subtle);
}

.sn-card__image {
  width: 100%;
  aspect-ratio: 4 / 3;
  object-fit: cover;
}

/* --- Badges --- */

.sn-badge {
  display: inline-flex;
  align-items: center;
  gap: var(--sn-space-xs);
  padding: 2px var(--sn-space-sm);
  font-size: var(--sn-font-size-xs);
  font-weight: var(--sn-font-weight-medium);
  line-height: 1.4;
  border-radius: var(--sn-border-radius-sm);
  color: var(--sn-color-text-on-accent);
  white-space: nowrap;
}

/* Fiber tier badges */
.sn-badge--pure     { background: var(--sn-color-fiber-pure); }
.sn-badge--majority { background: var(--sn-color-fiber-majority); }
.sn-badge--blend    { background: var(--sn-color-fiber-blend); }
.sn-badge--mended   { background: var(--sn-color-fiber-mended); color: var(--sn-color-text-primary); }

/* Status badges */
.sn-badge--success  { background: var(--sn-color-status-success); }
.sn-badge--danger   { background: var(--sn-color-status-danger); }
.sn-badge--info     { background: var(--sn-color-status-info); }
.sn-badge--warning  { background: var(--sn-color-status-warning); color: var(--sn-color-text-primary); }
.sn-badge--neutral  { background: var(--sn-color-surface-tertiary); color: var(--sn-color-text-secondary); }

/* --- Forms --- */

.sn-form-group {
  margin-bottom: var(--sn-space-md);
}

.sn-label {
  display: block;
  margin-bottom: var(--sn-space-xs);
  font-size: var(--sn-font-size-sm);
  font-weight: var(--sn-font-weight-medium);
  color: var(--sn-color-text-primary);
}

.sn-input,
.sn-select,
.sn-textarea {
  width: 100%;
  padding: var(--sn-space-sm) var(--sn-space-md);
  font-family: var(--sn-font-family-body);
  font-size: var(--sn-font-size-md);
  color: var(--sn-color-text-primary);
  background: var(--sn-color-surface-default);
  border: var(--sn-border-width-sm) solid var(--sn-color-border-default);
  border-radius: var(--sn-border-radius-md);
  transition: border-color var(--sn-transition-fast),
              box-shadow var(--sn-transition-fast);
}

.sn-input:hover,
.sn-select:hover,
.sn-textarea:hover {
  border-color: var(--sn-color-border-strong);
}

.sn-input:focus,
.sn-select:focus,
.sn-textarea:focus {
  outline: none;
  border-color: var(--sn-color-interactive-focus);
  box-shadow: var(--sn-shadow-focus);
}

.sn-input--error,
.sn-select--error,
.sn-textarea--error {
  border-color: var(--sn-color-status-danger);
}

.sn-input--error:focus,
.sn-select--error:focus,
.sn-textarea--error:focus {
  box-shadow: var(--sn-shadow-focus-danger);
}

.sn-form-hint {
  display: block;
  margin-top: var(--sn-space-xs);
  font-size: var(--sn-font-size-xs);
  color: var(--sn-color-text-muted);
}

.sn-form-error {
  display: block;
  margin-top: var(--sn-space-xs);
  font-size: var(--sn-font-size-xs);
  color: var(--sn-color-status-danger);
}

/* --- Tables --- */

.sn-table {
  width: 100%;
  border-collapse: collapse;
}

.sn-table th {
  text-align: left;
  padding: var(--sn-space-sm) var(--sn-space-md);
  background: var(--sn-color-surface-secondary);
  font-weight: var(--sn-font-weight-semibold);
  font-size: var(--sn-font-size-xs);
  color: var(--sn-color-text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  border-bottom: var(--sn-border-width-md) solid var(--sn-color-border-default);
}

.sn-table td {
  padding: var(--sn-space-sm) var(--sn-space-md);
  font-size: var(--sn-font-size-sm);
  border-bottom: var(--sn-border-width-sm) solid var(--sn-color-border-subtle);
  vertical-align: middle;
}

.sn-table tbody tr:hover {
  background: var(--sn-color-surface-secondary);
}

/* --- Alerts --- */

.sn-alert {
  padding: var(--sn-space-md);
  border-radius: var(--sn-border-radius-md);
  border-left: 4px solid;
  margin-bottom: var(--sn-space-md);
  font-size: var(--sn-font-size-sm);
}

.sn-alert--success {
  border-color: var(--sn-color-status-success);
  background: var(--sn-color-status-success-bg);
  color: var(--sn-color-text-primary);
}

.sn-alert--danger {
  border-color: var(--sn-color-status-danger);
  background: var(--sn-color-status-danger-bg);
  color: var(--sn-color-text-primary);
}

.sn-alert--warning {
  border-color: var(--sn-color-status-warning);
  background: var(--sn-color-status-warning-bg);
  color: var(--sn-color-text-primary);
}

.sn-alert--info {
  border-color: var(--sn-color-status-info);
  background: var(--sn-color-status-info-bg);
  color: var(--sn-color-text-primary);
}

/* --- Pagination --- */

.sn-pagination {
  display: flex;
  gap: var(--sn-space-xs);
  align-items: center;
}

.sn-pagination__item {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 2rem;
  padding: var(--sn-space-xs) var(--sn-space-sm);
  border: var(--sn-border-width-sm) solid var(--sn-color-border-default);
  border-radius: var(--sn-border-radius-sm);
  font-size: var(--sn-font-size-sm);
  color: var(--sn-color-text-primary);
  text-decoration: none;
  transition: background-color var(--sn-transition-fast),
              border-color var(--sn-transition-fast);
}

.sn-pagination__item:hover {
  background: var(--sn-color-surface-secondary);
  border-color: var(--sn-color-border-strong);
}

.sn-pagination__item--active {
  background: var(--sn-color-interactive-default);
  color: var(--sn-color-text-on-accent);
  border-color: var(--sn-color-interactive-default);
}

.sn-pagination__item--disabled {
  opacity: 0.4;
  cursor: not-allowed;
  pointer-events: none;
}

/* --- Stat Cards (admin dashboard) --- */

.sn-stat-card {
  background: var(--sn-color-surface-raised);
  border-radius: var(--sn-border-radius-lg);
  padding: var(--sn-space-lg);
  box-shadow: var(--sn-shadow-sm);
}

.sn-stat-card__label {
  font-size: var(--sn-font-size-sm);
  color: var(--sn-color-text-secondary);
  font-weight: var(--sn-font-weight-medium);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.sn-stat-card__value {
  font-family: var(--sn-font-family-heading);
  font-size: var(--sn-font-size-3xl);
  font-weight: var(--sn-font-weight-bold);
  color: var(--sn-color-text-primary);
  margin-top: var(--sn-space-xs);
}

/* --- Breadcrumbs --- */

.sn-breadcrumb {
  display: flex;
  align-items: center;
  gap: var(--sn-space-sm);
  font-size: var(--sn-font-size-sm);
  color: var(--sn-color-text-muted);
  margin-bottom: var(--sn-space-md);
}

.sn-breadcrumb a {
  color: var(--sn-color-text-secondary);
  text-decoration: none;
}

.sn-breadcrumb a:hover {
  color: var(--sn-color-interactive-default);
}

.sn-breadcrumb__separator::before {
  content: '/';
  margin: 0 var(--sn-space-xs);
}

/* --- Tags --- */

.sn-tag {
  display: inline-flex;
  align-items: center;
  gap: var(--sn-space-xs);
  padding: var(--sn-space-xs) var(--sn-space-sm);
  font-size: var(--sn-font-size-xs);
  border: var(--sn-border-width-sm) solid var(--sn-color-border-default);
  border-radius: var(--sn-border-radius-pill);
  color: var(--sn-color-text-secondary);
  background: var(--sn-color-surface-default);
}

/* ==========================================================================
   6. LAYOUT UTILITIES
   ========================================================================== */

.sn-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--sn-space-md);
}

.sn-grid {
  display: grid;
  gap: var(--sn-space-md);
}

.sn-grid--products {
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
}

.sn-grid--2col {
  grid-template-columns: 1fr 1fr;
}

.sn-grid--3col {
  grid-template-columns: repeat(3, 1fr);
}

.sn-grid--4col {
  grid-template-columns: repeat(4, 1fr);
}

.sn-flex {
  display: flex;
  gap: var(--sn-space-sm);
  align-items: center;
}

.sn-flex--between {
  justify-content: space-between;
}

.sn-flex--wrap {
  flex-wrap: wrap;
}

.sn-flex--column {
  flex-direction: column;
  align-items: stretch;
}

/* Screen reader only */
.sn-sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* ==========================================================================
   7. RESPONSIVE ADJUSTMENTS
   ========================================================================== */

/* --sn-breakpoint-md: 768px */
@media (max-width: 768px) {
  .sn-grid--2col,
  .sn-grid--3col,
  .sn-grid--4col {
    grid-template-columns: 1fr;
  }
}

/* ==========================================================================
   8. BASE LAYOUT (marketplace)
   Header, navigation, footer for the public-facing marketplace.
   ========================================================================== */

/* --- Header --- */

.sn-header {
  background: var(--sn-color-brand-primary);
  color: var(--sn-color-text-on-dark);
  padding: var(--sn-space-md) 0;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: var(--sn-shadow-md);
}

.sn-header a {
  color: var(--sn-color-text-on-dark);
  text-decoration: none;
  padding: var(--sn-space-sm) 0;
  position: relative;
  transition: opacity var(--sn-transition-normal);
}

.sn-header a:hover {
  opacity: 0.85;
}

.sn-header a:focus-visible {
  outline: var(--sn-border-width-md) solid var(--sn-color-interactive-default);
  outline-offset: 2px;
}

.sn-header__nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.sn-header__logo {
  font-family: var(--sn-font-family-heading);
  font-size: var(--sn-font-size-2xl);
  font-weight: var(--sn-font-weight-bold);
  letter-spacing: -0.5px;
}

.sn-header__links {
  display: flex;
  gap: var(--sn-space-lg);
  align-items: center;
}

.sn-header__links a:not(.sn-header__logo)::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--sn-color-interactive-default);
  transition: width var(--sn-transition-normal);
}

.sn-header__links a:not(.sn-header__logo):hover::after {
  width: 100%;
}

.sn-header__admin-link {
  color: var(--sn-color-interactive-default) !important;
  font-weight: var(--sn-font-weight-medium);
}

/* --- Main Content --- */

.sn-main {
  padding: var(--sn-space-xl) 0;
  min-height: calc(100vh - 180px);
}

/* --- Footer --- */

.sn-footer {
  background: var(--sn-color-brand-primary);
  padding: var(--sn-space-2xl) 0;
  color: var(--sn-color-on-dark-primary);
}

.sn-footer a {
  color: var(--sn-color-on-dark-primary);
  text-decoration: none;
  transition: color var(--sn-transition-normal);
}

.sn-footer a:hover {
  color: var(--sn-color-interactive-default);
}

.sn-footer__content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--sn-space-md);
}

.sn-footer__links {
  display: flex;
  gap: var(--sn-space-xl);
}

.sn-footer__links a {
  font-size: var(--sn-font-size-sm);
}

/* --- Storefront-specific elements --- */

.sn-header__brand {
  display: flex;
  align-items: center;
  gap: var(--sn-space-sm);
}

.sn-header__store-logo {
  height: 40px;
  width: auto;
  object-fit: contain;
  display: inline-block;
}

.sn-header__store-name {
  font-family: var(--sn-font-family-heading);
  font-size: var(--sn-font-size-2xl);
  font-weight: var(--sn-font-weight-bold);
  letter-spacing: -0.5px;
}

.sn-header__search {
  display: flex;
  gap: var(--sn-space-sm);
}

.sn-header__search input {
  padding: var(--sn-space-sm) var(--sn-space-md);
  border: none;
  border-radius: var(--sn-border-radius-md);
  font-size: var(--sn-font-size-sm);
  width: 200px;
}

.sn-header__search input:focus {
  outline: var(--sn-border-width-md) solid var(--sn-color-brand-accent);
}

.sn-header__search button {
  padding: var(--sn-space-sm) var(--sn-space-md);
  background: var(--sn-color-brand-accent);
  color: var(--sn-color-brand-primary);
  border: none;
  border-radius: var(--sn-border-radius-md);
  cursor: pointer;
  font-weight: var(--sn-font-weight-medium);
}

.sn-header__search button:hover {
  opacity: 0.9;
}

.sn-footer__brand {
  max-width: 300px;
}

.sn-footer__brand .sn-header__store-name {
  font-size: var(--sn-font-size-xl);
  margin-bottom: var(--sn-space-sm);
  color: var(--sn-color-text-on-dark);
}

.sn-footer__brand p {
  font-size: var(--sn-font-size-sm);
  line-height: var(--sn-line-height-normal);
}

.sn-footer__powered {
  width: 100%;
  text-align: center;
  padding-top: var(--sn-space-lg);
  margin-top: var(--sn-space-lg);
  border-top: 1px solid var(--sn-color-on-dark-border);
  font-size: var(--sn-font-size-sm);
}

.sn-footer__powered a {
  color: var(--sn-color-brand-accent);
  font-weight: var(--sn-font-weight-medium);
}

/* --- Responsive: Base Layout --- */

/* --sn-breakpoint-md: 768px */
@media (max-width: 768px) {
  .sn-header__nav {
    flex-direction: column;
    gap: var(--sn-space-md);
  }

  .sn-header__links {
    gap: var(--sn-space-md);
    flex-wrap: wrap;
    justify-content: center;
  }

  .sn-footer__content {
    flex-direction: column;
    text-align: center;
  }

  .sn-footer__links {
    flex-direction: column;
    gap: var(--sn-space-sm);
  }

  .sn-header__search input {
    width: 150px;
  }
}

/* ==========================================================================
   9. ADMIN LAYOUT
   Sidebar, header, and content area for the admin panel.
   ========================================================================== */

.sn-admin {
  display: flex;
  min-height: 100vh;
}

/* --- Sidebar --- */

.sn-admin__sidebar {
  width: var(--sn-admin-sidebar-width);
  background: var(--sn-color-brand-primary);
  color: var(--sn-color-text-on-dark);
  position: fixed;
  top: 0;
  left: 0;
  bottom: 0;
  overflow-y: auto;
}

.sn-admin__sidebar-header {
  padding: var(--sn-space-lg) var(--sn-space-md);
  border-bottom: 1px solid var(--sn-color-on-dark-hover);
}

.sn-admin__sidebar-header .sn-admin__logo {
  font-family: var(--sn-font-family-heading);
  font-size: var(--sn-font-size-xl);
  font-weight: var(--sn-font-weight-bold);
  color: var(--sn-color-text-on-dark);
  text-decoration: none;
  display: block;
}

.sn-admin__sidebar-header .sn-admin__subtitle {
  font-size: var(--sn-font-size-xs);
  color: var(--sn-color-on-dark-secondary);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin-top: var(--sn-space-xs);
}

/* --- Sidebar Navigation --- */

.sn-admin__nav {
  padding: var(--sn-space-md) 0;
}

.sn-admin__nav-section {
  margin-bottom: var(--sn-space-lg);
}

.sn-admin__nav-title {
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--sn-color-on-dark-muted);
  padding: 0 var(--sn-space-md);
  margin-bottom: var(--sn-space-sm);
}

.sn-admin__nav a {
  display: flex;
  align-items: center;
  gap: var(--sn-space-sm);
  padding: var(--sn-space-sm) var(--sn-space-md);
  color: var(--sn-color-on-dark-primary);
  text-decoration: none;
  transition: all var(--sn-transition-normal);
}

.sn-admin__nav a:hover {
  background: var(--sn-color-on-dark-hover);
  color: var(--sn-color-text-on-dark);
}

.sn-admin__nav a.active {
  background: var(--sn-color-interactive-tint-active);
  color: var(--sn-color-interactive-default);
  border-left: 3px solid var(--sn-color-interactive-default);
}

.sn-admin__nav-icon {
  width: 18px;
  height: 18px;
  opacity: 0.8;
  display: inline-block;
}

/* --- Main Content Area --- */

.sn-admin__main {
  flex: 1;
  margin-left: var(--sn-admin-sidebar-width);
}

.sn-admin__header {
  background: var(--sn-color-surface-default);
  padding: var(--sn-space-md) var(--sn-space-xl);
  border-bottom: var(--sn-border-width-sm) solid var(--sn-color-border-subtle);
  display: flex;
  justify-content: space-between;
  align-items: center;
  position: sticky;
  top: 0;
  z-index: 10;
}

.sn-admin__header h1 {
  font-size: var(--sn-font-size-xl);
  font-weight: var(--sn-font-weight-semibold);
}

.sn-admin__user-info {
  display: flex;
  align-items: center;
  gap: var(--sn-space-md);
}

.sn-admin__user-email {
  font-size: var(--sn-font-size-sm);
  color: var(--sn-color-text-secondary);
}

.sn-admin__content {
  padding: var(--sn-space-xl);
}

/* --- Responsive: Admin Layout --- */

/* --sn-breakpoint-md: 768px */
@media (max-width: 768px) {
  .sn-admin__sidebar {
    width: var(--sn-admin-sidebar-width-collapsed);
  }

  .sn-admin__sidebar-header .sn-admin__logo,
  .sn-admin__sidebar-header .sn-admin__subtitle,
  .sn-admin__nav-title,
  .sn-admin__nav a span {
    display: none;
  }

  .sn-admin__nav a {
    justify-content: center;
    padding: var(--sn-space-md);
  }

  .sn-admin__main {
    margin-left: var(--sn-admin-sidebar-width-collapsed);
  }

  .sn-admin__content {
    padding: var(--sn-space-md);
  }
}

/* ==========================================================================
   10. LEGACY COMPATIBILITY
   Backward-compatible aliases for old class names used by page templates.
   These map old classes to design tokens so pages work during incremental
   migration. Remove individual aliases as pages are migrated to .sn-* classes.
   ========================================================================== */

/* --- Legacy Buttons --- */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: var(--sn-space-sm) var(--sn-space-md);
  border: var(--sn-border-width-sm) solid transparent;
  border-radius: var(--sn-border-radius-md);
  cursor: pointer;
  text-decoration: none;
  font-family: var(--sn-font-family-body);
  font-size: var(--sn-font-size-sm);
  font-weight: var(--sn-font-weight-medium);
  line-height: 1;
  transition: background-color var(--sn-transition-fast),
              border-color var(--sn-transition-fast),
              transform var(--sn-transition-fast);
  white-space: nowrap;
}
.btn:focus-visible {
  outline: var(--sn-border-width-md) solid var(--sn-color-interactive-focus);
  outline-offset: 2px;
}
.btn-primary {
  background: var(--sn-color-interactive-secondary);
  color: var(--sn-color-text-on-dark);
  border-color: var(--sn-color-interactive-secondary);
}
.btn-primary:hover { background: var(--sn-color-interactive-secondary-hover); }
.btn-secondary {
  background: var(--sn-color-surface-secondary);
  color: var(--sn-color-text-primary);
  border-color: var(--sn-color-border-default);
}
.btn-secondary:hover {
  background: var(--sn-color-border-strong);
}
.btn-success {
  background: var(--sn-color-interactive-default);
  color: var(--sn-color-text-on-accent);
  border-color: var(--sn-color-interactive-default);
}
.btn-success:hover { background: var(--sn-color-interactive-hover); }
.btn-danger {
  background: var(--sn-color-status-danger);
  color: var(--sn-color-text-on-accent);
  border-color: var(--sn-color-status-danger);
}
.btn-danger:hover { background: var(--sn-color-status-danger-hover); }
.btn-warning {
  background: var(--sn-color-status-warning);
  color: var(--sn-color-text-primary);
  border-color: var(--sn-color-status-warning);
}
.btn-warning:hover { background: var(--sn-color-status-warning-hover); }
.btn-sm {
  padding: var(--sn-space-xs) var(--sn-space-sm);
  font-size: var(--sn-font-size-xs);
}

/* --- Legacy Forms --- */

.form-group {
  margin-bottom: var(--sn-space-md);
}
.form-group label {
  display: block;
  margin-bottom: var(--sn-space-xs);
  font-weight: var(--sn-font-weight-medium);
  color: var(--sn-color-text-primary);
}
.form-group input,
.form-group select,
.form-group textarea,
.form-control {
  width: 100%;
  padding: var(--sn-space-sm) var(--sn-space-md);
  border: var(--sn-border-width-sm) solid var(--sn-color-border-default);
  border-radius: var(--sn-border-radius-md);
  font-family: var(--sn-font-family-body);
  font-size: var(--sn-font-size-md);
  color: var(--sn-color-text-primary);
  background: var(--sn-color-surface-default);
  transition: border-color var(--sn-transition-fast),
              box-shadow var(--sn-transition-fast);
}
.form-group input:hover,
.form-control:hover {
  border-color: var(--sn-color-border-strong);
}
.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus,
.form-control:focus {
  outline: none;
  border-color: var(--sn-color-interactive-focus);
  box-shadow: var(--sn-shadow-focus);
}
.form-group small {
  display: block;
  margin-top: var(--sn-space-xs);
  color: var(--sn-color-text-secondary);
  font-size: var(--sn-font-size-sm);
}

/* --- Legacy Alerts --- */

.alert {
  padding: var(--sn-space-md);
  border-radius: var(--sn-border-radius-md);
  margin-bottom: var(--sn-space-md);
  font-size: var(--sn-font-size-sm);
}
.alert-success {
  background: var(--sn-color-status-success-bg);
  color: var(--sn-color-text-primary);
  border: var(--sn-border-width-sm) solid var(--sn-color-status-success);
}
.alert-error {
  background: var(--sn-color-status-danger-bg);
  color: var(--sn-color-text-primary);
  border: var(--sn-border-width-sm) solid var(--sn-color-status-danger);
}
.alert-warning {
  background: var(--sn-color-status-warning-bg);
  color: var(--sn-color-text-primary);
  border: var(--sn-border-width-sm) solid var(--sn-color-status-warning);
}

/* --- Legacy Messages (used in login/register pages) --- */

.error {
  color: var(--sn-color-status-danger);
  font-size: var(--sn-font-size-sm);
  padding: var(--sn-space-sm) var(--sn-space-md);
  background: var(--sn-color-status-danger-bg);
  border-radius: var(--sn-border-radius-sm);
  margin-bottom: var(--sn-space-md);
}
.success {
  color: var(--sn-color-status-success);
  font-size: var(--sn-font-size-sm);
  padding: var(--sn-space-sm) var(--sn-space-md);
  background: var(--sn-color-status-success-bg);
  border-radius: var(--sn-border-radius-sm);
  margin-bottom: var(--sn-space-md);
}

/* --- Legacy Badges --- */

.badge {
  display: inline-flex;
  align-items: center;
  padding: 2px var(--sn-space-sm);
  border-radius: var(--sn-border-radius-sm);
  font-size: var(--sn-font-size-xs);
  font-weight: var(--sn-font-weight-medium);
}
.badge-success { background: rgba(0, 184, 148, 0.15); color: var(--sn-color-text-primary); }
.badge-warning { background: rgba(253, 203, 110, 0.25); color: var(--sn-color-text-primary); }
.badge-danger  { background: rgba(214, 48, 49, 0.12); color: var(--sn-color-status-danger); }
.badge-info    { background: rgba(9, 132, 227, 0.12); color: var(--sn-color-status-info); }
.badge-secondary { background: var(--sn-color-surface-tertiary); color: var(--sn-color-text-secondary); }

/* --- Legacy Cards --- */

.card {
  background: var(--sn-color-surface-raised);
  border-radius: var(--sn-border-radius-lg);
  box-shadow: var(--sn-shadow-sm);
}
.card-header {
  padding: var(--sn-space-md);
  border-bottom: var(--sn-border-width-sm) solid var(--sn-color-border-subtle);
  font-weight: var(--sn-font-weight-semibold);
}
.card-body {
  padding: var(--sn-space-md);
}

/* --- Legacy Tables --- */

.table {
  width: 100%;
  border-collapse: collapse;
}
.table th,
.table td {
  padding: var(--sn-space-sm) var(--sn-space-md);
  text-align: left;
  border-bottom: var(--sn-border-width-sm) solid var(--sn-color-border-subtle);
  vertical-align: middle;
}
.table th {
  background: var(--sn-color-surface-secondary);
  font-weight: var(--sn-font-weight-semibold);
  color: var(--sn-color-text-secondary);
  font-size: var(--sn-font-size-xs);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}
.table tbody tr:hover {
  background: var(--sn-color-surface-secondary);
}

/* --- Legacy Utilities --- */

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--sn-space-md);
}
.text-muted { color: var(--sn-color-text-secondary); }
.text-center { text-align: center; }
.mt-1 { margin-top: var(--sn-space-sm); }
.mt-2 { margin-top: var(--sn-space-md); }
.mb-1 { margin-bottom: var(--sn-space-sm); }
.mb-2 { margin-bottom: var(--sn-space-md); }
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}