/* =========================================================
 * Variables
 * ======================================================= */

:root {
  /* Colors */
  --color-bg: #f4f5f7;
  --color-surface: #ffffff;
  --color-surface-muted: #f0f2f5;

  --color-text: #121722;
  --color-text-muted: #6b7280;
  --color-border-subtle: #d1d5db;

  --color-primary: #1e3a8a; /* deep industrial blue */
  --color-primary-soft: #e0e7ff;
  --color-primary-strong: #111827;

  --color-accent: #facc15; /* safety yellow */
  --color-accent-soft: #fef9c3;

  --color-success: #16a34a;
  --color-success-soft: #dcfce7;
  --color-warning: #f59e0b;
  --color-warning-soft: #fef3c7;
  --color-danger: #dc2626;
  --color-danger-soft: #fee2e2;

  /* Neutral grays (industrial, clean) */
  --gray-50: #f9fafb;
  --gray-100: #f3f4f6;
  --gray-200: #e5e7eb;
  --gray-300: #d1d5db;
  --gray-400: #9ca3af;
  --gray-500: #6b7280;
  --gray-600: #4b5563;
  --gray-700: #374151;
  --gray-800: #1f2933;
  --gray-900: #111827;

  /* Typography */
  --font-sans: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --font-mono: "SF Mono", Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;

  --font-size-xs: 0.75rem;   /* 12px */
  --font-size-sm: 0.875rem;  /* 14px */
  --font-size-md: 1rem;      /* 16px */
  --font-size-lg: 1.125rem;  /* 18px */
  --font-size-xl: 1.25rem;   /* 20px */
  --font-size-2xl: 1.5rem;   /* 24px */
  --font-size-3xl: 1.875rem; /* 30px */
  --font-size-4xl: 2.25rem;  /* 36px */

  --line-height-tight: 1.2;
  --line-height-base: 1.5;
  --line-height-relaxed: 1.7;

  /* Spacing scale (0–96px) */
  --space-0: 0;
  --space-1: 0.25rem;  /* 4px */
  --space-2: 0.5rem;   /* 8px */
  --space-3: 0.75rem;  /* 12px */
  --space-4: 1rem;     /* 16px */
  --space-5: 1.25rem;  /* 20px */
  --space-6: 1.5rem;   /* 24px */
  --space-8: 2rem;     /* 32px */
  --space-10: 2.5rem;  /* 40px */
  --space-12: 3rem;    /* 48px */
  --space-16: 4rem;    /* 64px */
  --space-20: 5rem;    /* 80px */
  --space-24: 6rem;    /* 96px */

  /* Radius */
  --radius-xs: 2px;
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-xl: 20px;
  --radius-pill: 9999px;

  /* Shadows (industrial, subtle depth) */
  --shadow-soft: 0 1px 2px rgba(15, 23, 42, 0.06);
  --shadow-md: 0 4px 10px rgba(15, 23, 42, 0.08);
  --shadow-lg: 0 12px 30px rgba(15, 23, 42, 0.18);

  /* Transitions */
  --transition-fast: 120ms ease-out;
  --transition-base: 180ms ease-out;
  --transition-slow: 250ms ease-out;

  /* Layout */
  --layout-max-width: 1200px;
}

/* Respect reduced motion preferences */
@media (prefers-reduced-motion: reduce) {
  :root {
    --transition-fast: 0s;
    --transition-base: 0s;
    --transition-slow: 0s;
  }

  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

/* =========================================================
 * Reset / Normalize
 * ======================================================= */

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

html,
body {
  margin: 0;
  padding: 0;
}

html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body {
  min-height: 100vh;
}

img,
svg,
video,
canvas,
audio,
iframe,
embed,
object {
  max-width: 100%;
  height: auto;
}

img {
  display: block;
}

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

button {
  border: none;
  padding: 0;
  background: none;
  cursor: pointer;
}

ul,
ol {
  margin: 0;
  padding: 0;
  list-style: none;
}

h1,
h2,
h3,
h4,
h5,
h6,
p,
figure,
blockquote,
dl,
dd {
  margin: 0;
}

fieldset {
  margin: 0;
  padding: 0;
  border: 0;
}

textarea {
  resize: vertical;
}

/* Improve text rendering */
body,
button,
input,
select,
textarea {
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* =========================================================
 * Base Styles
 * ======================================================= */

body {
  font-family: var(--font-sans);
  font-size: var(--font-size-md);
  line-height: var(--line-height-base);
  background-color: var(--color-bg);
  color: var(--color-text);
}

/* Headings – industrial, structured hierarchy */

h1,
h2,
h3,
h4,
h5,
h6 {
  font-weight: 600;
  color: var(--color-primary-strong);
  line-height: var(--line-height-tight);
}

h1 {
  font-size: var(--font-size-4xl);
  margin-bottom: var(--space-4);
}

h2 {
  font-size: var(--font-size-3xl);
  margin-bottom: var(--space-3);
}

h3 {
  font-size: var(--font-size-2xl);
  margin-bottom: var(--space-2);
}

h4 {
  font-size: var(--font-size-xl);
  margin-bottom: var(--space-2);
}

h5 {
  font-size: var(--font-size-lg);
  margin-bottom: var(--space-1);
}

h6 {
  font-size: var(--font-size-sm);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--gray-500);
  margin-bottom: var(--space-1);
}

/* Paragraphs – comfortable line length for specs and descriptions */

p {
  margin-bottom: var(--space-3);
  }

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

/* Links – clean, purposeful */

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color var(--transition-base),
    text-decoration-color var(--transition-base);
}

a:hover {
  color: var(--color-primary-strong);
}

a:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}

/* Strong text */

strong,
b {
  font-weight: 600;
}

/* Code (for technical specifications, SKUs) */

code,
pre {
  font-family: var(--font-mono);
  font-size: 0.95em;
}

pre {
  padding: var(--space-3);
  background-color: var(--gray-900);
  color: #f9fafb;
  border-radius: var(--radius-sm);
  overflow-x: auto;
}

/* =========================================================
 * Accessibility & Focus
 * ======================================================= */

:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 3px;
}

/* Screen-reader only utility */

.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;
}

.sr-only-focusable:active,
.sr-only-focusable:focus {
  position: static;
  width: auto;
  height: auto;
  margin: 0;
  overflow: visible;
  clip: auto;
  white-space: normal;
}

/* =========================================================
 * Utilities
 * ======================================================= */

/* Layout container – centered, constrained width */

.container {
  width: 100%;
  max-width: var(--layout-max-width);
  margin-left: auto;
  margin-right: auto;
  padding-left: var(--space-4);
  padding-right: var(--space-4);
}

@media (min-width: 1024px) {
  .container {
    padding-left: var(--space-6);
    padding-right: var(--space-6);
  }
}

/* Flex utilities */

.flex {
  display: flex;
}

.inline-flex {
  display: inline-flex;
}

.flex-center {
  display: flex;
  align-items: center;
  justify-content: center;
}

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

.flex-col {
  display: flex;
  flex-direction: column;
}

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

.gap-2 {
  gap: var(--space-2);
}

.gap-3 {
  gap: var(--space-3);
}

.gap-4 {
  gap: var(--space-4);
}

/* Grid utilities – for product listing, filters */

.grid {
  display: grid;
}

.grid-2 {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: var(--space-4);
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: var(--space-4);
}

.grid-auto-fit-min-200 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: var(--space-4);
}

/* Alignment and text utilities */

.text-center {
  text-align: center;
}

.text-right {
  text-align: right;
}

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

/* Spacing utilities (common values for layout tuning) */

.mt-0 { margin-top: 0; }
.mt-2 { margin-top: var(--space-2); }
.mt-3 { margin-top: var(--space-3); }
.mt-4 { margin-top: var(--space-4); }
.mt-6 { margin-top: var(--space-6); }

.mb-0 { margin-bottom: 0; }
.mb-2 { margin-bottom: var(--space-2); }
.mb-3 { margin-bottom: var(--space-3); }
.mb-4 { margin-bottom: var(--space-4); }
.mb-6 { margin-bottom: var(--space-6); }

.pt-4 { padding-top: var(--space-4); }
.pb-4 { padding-bottom: var(--space-4); }
.pl-4 { padding-left: var(--space-4); }
.pr-4 { padding-right: var(--space-4); }

/* Surface utilities */

.surface {
  background-color: var(--color-surface);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-soft);
}

.surface-muted {
  background-color: var(--color-surface-muted);
  border-radius: var(--radius-md);
}

/* =========================================================
 * Components
 * ======================================================= */

/* Buttons – primary action, industrial but friendly */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: 0.625rem 1.25rem; /* 10px 20px */
  border-radius: var(--radius-pill);
  font-size: var(--font-size-sm);
  font-weight: 600;
  letter-spacing: 0.02em;
  text-transform: uppercase;
  border: 1px solid transparent;
  transition:
    background-color var(--transition-base),
    color var(--transition-base),
    border-color var(--transition-base),
    box-shadow var(--transition-base),
    transform var(--transition-fast);
  cursor: pointer;
  white-space: nowrap;
}

.btn-primary {
  background: linear-gradient(135deg, #1f2937, var(--color-primary));
  color: #ffffff!important;
  box-shadow: var(--shadow-md);
}

.btn-primary:hover {
  background: linear-gradient(135deg, #0f172a, var(--color-primary-strong));
  box-shadow: var(--shadow-lg);
  transform: translateY(-1px);
}

.btn-primary:active {
  transform: translateY(0);
  box-shadow: var(--shadow-soft);
}

.btn-secondary {
  background-color: var(--gray-900);
  color: #f9fafb;
  border-color: var(--gray-800);
}

.btn-secondary:hover {
  background-color: #020617;
  border-color: #020617;
}

.btn-outline {
  background-color: #ffffff;
  color: var(--color-primary-strong);
  border-color: var(--gray-400);
}

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

.btn-accent {
  background-color: var(--color-accent);
  color: #1f2937;
  border-color: #d4af0a;
}

.btn-accent:hover {
  background-color: #eab308;
}

.btn:disabled,
.btn[aria-disabled="true"] {
  cursor: not-allowed;
  opacity: 0.55;
  box-shadow: none;
  transform: none;
}

.btn:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 3px;
}

/* Inputs – consistent, professional, good focus state */

.input,
select,
textarea {
  width: 100%;
  padding: 0.625rem 0.75rem;
  font-size: var(--font-size-sm);
  border-radius: var(--radius-sm);
  border: 1px solid var(--color-border-subtle);
  background-color: var(--color-surface);
  color: var(--color-text);
  transition:
    border-color var(--transition-base),
    box-shadow var(--transition-base),
    background-color var(--transition-base);
}

.input::placeholder,
textarea::placeholder {
  color: var(--gray-400);
}

.input:focus-visible,
select:focus-visible,
textarea:focus-visible {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 1px var(--color-primary-soft), 0 0 0 3px rgba(30, 64, 175, 0.25);
}

.input[disabled],
select[disabled],
textarea[disabled] {
  background-color: var(--gray-100);
  cursor: not-allowed;
  color: var(--gray-500);
}

/* Cards – for product tiles, info blocks */

.card {
  background-color: var(--color-surface);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  padding: var(--space-4);
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  border: 1px solid rgba(15, 23, 42, 0.06);
}

.card--muted {
  background-color: var(--color-surface-muted);
}

.card-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: var(--space-3);
}

.card-title {
  font-size: var(--font-size-lg);
  font-weight: 600;
  color: var(--color-primary-strong);
}

.card-subtitle {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
}

.card-media {
  border-radius: var(--radius-md);
  overflow: hidden;
}

.card-media img {
  width: 100%;
  height: auto;
  object-fit: cover;
  display: block;
}

.card-footer {
  margin-top: auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
  flex-wrap: wrap;
}

/* Badges – status indicators for availability, promos */

.badge {
  display: inline-flex;
  align-items: center;
  padding: 0.25rem 0.5rem;
  border-radius: var(--radius-pill);
  font-size: var(--font-size-xs);
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.badge-success {
  color: #065f46;
  background-color: var(--color-success-soft);
}

.badge-warning {
  color: #92400e;
  background-color: var(--color-warning-soft);
}

.badge-danger {
  color: #7f1d1d;
  background-color: var(--color-danger-soft);
}

.badge-accent {
  color: #1f2937;
  background-color: var(--color-accent-soft);
}

/* Utility: elevated sticky header/footer bars (e.g., filter bar, checkout summary) */

.bar-elevated {
  background-color: rgba(15, 23, 42, 0.96);
  color: #e5e7eb;
  box-shadow: 0 1px 0 rgba(15, 23, 42, 0.65);
  backdrop-filter: blur(12px);
}

/* Chat bubble container (for support chat UI shell) */

.chat-bubble {
  padding: var(--space-3);
  border-radius: var(--radius-lg);
  background-color: var(--color-surface);
  box-shadow: var(--shadow-lg);
  border: 1px solid rgba(15, 23, 42, 0.08);
}

.chat-bubble--agent {
  border-left: 3px solid var(--color-primary);
}

.chat-bubble--user {
  border-left: 3px solid var(--color-accent);
}

/* Subtle hover lift for interactive cards and tiles */

.hover-lift {
  transition:
    transform var(--transition-base),
    box-shadow var(--transition-base),
    border-color var(--transition-base);
}

.hover-lift:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
  border-color: rgba(15, 23, 42, 0.18);
}

.hover-lift:active {
  transform: translateY(0);
  box-shadow: var(--shadow-md);
}