/* =========================================
   Variables
   ========================================= */
:root {
  /* Color Palette */
  --color-background: #f4f5f7; /* subtle light gray */
  --color-surface: #ffffff; /* card & panels */
  --color-surface-muted: #f0f2f5;

  --color-text: #1f2933; /* graphite-like dark */
  --color-text-muted: #6b7280;
  --color-border-subtle: #d1d5db;

  --color-primary: #2563eb; /* electric blue */
  --color-primary-soft: #dbeafe;
  --color-primary-strong: #1d4ed8;

  --color-success: #16a34a;
  --color-warning: #f59e0b;
  --color-danger: #dc2626;

  --color-gray-50: #f9fafb;
  --color-gray-100: #f3f4f6;
  --color-gray-200: #e5e7eb;
  --color-gray-300: #d1d5db;
  --color-gray-400: #9ca3af;
  --color-gray-500: #6b7280;
  --color-gray-600: #4b5563;
  --color-gray-700: #374151;
  --color-gray-800: #1f2933;
  --color-gray-900: #111827;

  /* Metallic accent (stainless steel) */
  --color-steel: #c0c6cf;

  /* Typography */
  --font-sans: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", "Liberation Sans", sans-serif;
  --font-heading: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", sans-serif;

  --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-normal: 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-7: 1.75rem;  /* 28px */
  --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-sm: 0.25rem;   /* 4px */
  --radius-md: 0.5rem;    /* 8px */
  --radius-lg: 0.75rem;   /* 12px */
  --radius-xl: 1rem;      /* 16px */
  --radius-pill: 9999px;

  /* Shadows (subtle, modern) */
  --shadow-sm: 0 1px 2px rgba(15, 23, 42, 0.05);
  --shadow-md: 0 4px 12px rgba(15, 23, 42, 0.08);
  --shadow-lg: 0 18px 45px rgba(15, 23, 42, 0.18);

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

  /* Layout */
  --layout-max-width: 1200px;
  --layout-page-padding: var(--space-4);

  /* Focus */
  --focus-ring-color: rgba(37, 99, 235, 0.65);
  --focus-ring-width: 2px;
  --focus-ring-offset: 2px;
}

/* =========================================
   Reset / Normalize
   ========================================= */
*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  margin: 0;
  padding: 0;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
}

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

ul,
 ol {
  margin: 0;
  padding: 0;
}

img,
 picture,
 video,
 canvas,
 svg {
  display: block;
  max-width: 100%;
}

iframe {
  max-width: 100%;
}

button,
 input,
 textarea,
 select {
  font: inherit;
  color: inherit;
  margin: 0;
}

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

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

/* Remove list bullets by default; can be overridden in components */
ul,
 ol {
  list-style: none;
}

/* =========================================
   Base Styles
   ========================================= */
body {
  font-family: var(--font-sans);
  font-size: var(--font-size-md);
  line-height: var(--line-height-normal);
  color: var(--color-text);
  background-color: var(--color-background);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

main {
  min-height: 100vh;
}

h1,
 h2,
 h3,
 h4,
 h5,
 h6 {
  font-family: var(--font-heading);
  font-weight: 600;
  line-height: var(--line-height-tight);
  color: var(--color-gray-900);
}

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-3);
}

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

h5 {
  font-size: var(--font-size-lg);
  margin-bottom: var(--space-2);
}

h6 {
  font-size: var(--font-size-sm);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-text-muted);
  margin-bottom: var(--space-1);
}

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

small {
  font-size: var(--font-size-xs);
}

strong {
  font-weight: 600;
}

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

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

a:focus-visible {
  outline: none;
}

hr {
  border: none;
  border-top: 1px solid var(--color-gray-200);
  margin: var(--space-6) 0;
}

code,
 pre {
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;
}

/* =========================================
   Accessibility & Motion
   ========================================= */
:focus-visible {
  outline: var(--focus-ring-width) solid var(--focus-ring-color);
  outline-offset: var(--focus-ring-offset);
}

:focus {
  outline: none;
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

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

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

/* Flex helpers */
.flex {
  display: flex;
}

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

.flex-row {
  flex-direction: row;
}

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

.justify-start {
  justify-content: flex-start;
}

.justify-center {
  justify-content: center;
}

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

.items-start {
  align-items: flex-start;
}

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

.items-end {
  align-items: flex-end;
}

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

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

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

.gap-lg {
  gap: var(--space-6);
}

/* Grid helpers */
.grid {
  display: grid;
}

.grid-cols-2 {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.grid-cols-3 {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.grid-cols-4 {
  grid-template-columns: repeat(4, minmax(0, 1fr));
}

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

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

.grid-gap-lg {
  gap: var(--space-6);
}

/* Spacing utilities (common) */
.mt-0 { margin-top: 0 !important; }
.mb-0 { margin-bottom: 0 !important; }
.mt-sm { margin-top: var(--space-2) !important; }
.mt-md { margin-top: var(--space-4) !important; }
.mt-lg { margin-top: var(--space-6) !important; }
.mb-sm { margin-bottom: var(--space-2) !important; }
.mb-md { margin-bottom: var(--space-4) !important; }
.mb-lg { margin-bottom: var(--space-6) !important; }

.py-sm {
  padding-top: var(--space-2) !important;
  padding-bottom: var(--space-2) !important;
}

.py-md {
  padding-top: var(--space-4) !important;
  padding-bottom: var(--space-4) !important;
}

.py-lg {
  padding-top: var(--space-6) !important;
  padding-bottom: var(--space-6) !important;
}

.px-sm {
  padding-left: var(--space-2) !important;
  padding-right: var(--space-2) !important;
}

.px-md {
  padding-left: var(--space-4) !important;
  padding-right: var(--space-4) !important;
}

.px-lg {
  padding-left: var(--space-6) !important;
  padding-right: var(--space-6) !important;
}

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

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

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

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

/* Screen reader only */
.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;
}

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

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.625rem 1.5rem;
  border-radius: var(--radius-pill);
  font-size: var(--font-size-sm);
  font-weight: 500;
  line-height: 1.2;
  border: 1px solid transparent;
  cursor: pointer;
  transition:
    background-color var(--transition-normal),
    color var(--transition-normal),
    border-color var(--transition-normal),
    box-shadow var(--transition-fast),
    transform var(--transition-fast);
}

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

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

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

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

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

.btn-ghost {
  background-color: transparent;
  color: var(--color-text);
}

.btn-ghost:hover {
  background-color: var(--color-gray-100);
}

.btn:disabled,
.btn[aria-disabled="true"] {
  cursor: not-allowed;
  opacity: 0.6;
  box-shadow: none;
}

.btn:focus-visible {
  outline: none;
}

/* Inputs & form controls */
.input,
 select,
 textarea {
  width: 100%;
  padding: 0.625rem 0.75rem;
  border-radius: var(--radius-md);
  border: 1px solid var(--color-gray-300);
  background-color: #ffffff;
  font-size: var(--font-size-sm);
  line-height: 1.4;
  color: var(--color-text);
  transition:
    border-color var(--transition-fast),
    box-shadow var(--transition-fast),
    background-color var(--transition-fast);
}

.input::placeholder,
 textarea::placeholder {
  color: var(--color-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 4px rgba(37, 99, 235, 0.12);
}

.input[aria-invalid="true"],
.input.error {
  border-color: var(--color-danger);
}

label {
  display: inline-block;
  margin-bottom: var(--space-1);
  font-size: var(--font-size-sm);
  font-weight: 500;
  color: var(--color-gray-800);
}

.form-helper {
  margin-top: var(--space-1);
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
}

.form-error {
  margin-top: var(--space-1);
  font-size: var(--font-size-xs);
  color: var(--color-danger);
}

/* Card component (for product tiles, info blocks) */
.card {
  position: relative;
  display: flex;
  flex-direction: column;
  background-color: var(--color-surface);
  border-radius: var(--radius-lg);
  border: 1px solid var(--color-gray-200);
  box-shadow: var(--shadow-sm);
  padding: var(--space-4);
  overflow: hidden;
  transition:
    box-shadow var(--transition-normal),
    transform var(--transition-normal),
    border-color var(--transition-normal),
    background-color var(--transition-normal);
}

.card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
  border-color: var(--color-gray-300);
}

.card-header {
  margin-bottom: var(--space-3);
}

.card-title {
  font-size: var(--font-size-lg);
  font-weight: 600;
  margin-bottom: var(--space-1);
}

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

.card-body {
  flex: 1 1 auto;
}

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

/* Product image wrapper for consistent aspect ratio */
.card-media {
  position: relative;
  border-radius: var(--radius-md);
  overflow: hidden;
  margin-bottom: var(--space-3);
  background: radial-gradient(circle at top left, rgba(192, 198, 207, 0.4), transparent 60%);
}

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

/* Subtle metallic edge accent for tech-driven feel */
.card::before {
  content: "";
  position: absolute;
  inset-inline-start: 0;
  top: 0;
  bottom: 0;
  width: 3px;
  background: linear-gradient(to bottom, rgba(192, 198, 207, 0.25), rgba(37, 99, 235, 0.35));
  opacity: 0;
  transition: opacity var(--transition-fast);
}

.card:hover::before {
  opacity: 1;
}

/* =========================================
   Responsive tweaks
   ========================================= */

@media (max-width: 767px) {
  :root {
    --layout-page-padding: var(--space-3);
  }

  h1 {
    font-size: var(--font-size-3xl);
  }

  h2 {
    font-size: var(--font-size-2xl);
  }

  .grid-cols-3,
  .grid-cols-4 {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 480px) {
  .grid-cols-2,
  .grid-cols-3,
  .grid-cols-4 {
    grid-template-columns: 1fr;
  }
}