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

:root {
  /* Colors */
  --color-background: #050b16; /* deep navy background */
  --color-surface: #0f172a;    /* elevated surfaces */
  --color-surface-soft: #111827;
  --color-text: #f9fafb;       /* primary text on dark */
  --color-text-muted: #9ca3af;
  --color-border-subtle: #1f2937;

  --color-primary: #22c55e;      /* energetic green */
  --color-primary-strong: #16a34a;
  --color-primary-soft: #bbf7d0;

  --color-success: #22c55e;
  --color-warning: #facc15;
  --color-danger: #f97373;

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

  /* Typography */
  --font-sans: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --font-heading: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --font-mono: SFMono-Regular, 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-snug: 1.35;
  --line-height-normal: 1.5;
  --line-height-relaxed: 1.7;

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

  /* Radius */
  --radius-xs: 2px;
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-xl: 18px;
  --radius-full: 9999px;

  /* Shadows (subtle but modern, for dark UI) */
  --shadow-xs: 0 1px 2px rgba(0, 0, 0, 0.35);
  --shadow-sm: 0 4px 12px rgba(15, 23, 42, 0.45);
  --shadow-md: 0 10px 30px rgba(15, 23, 42, 0.6);
  --shadow-lg: 0 18px 45px rgba(15, 23, 42, 0.75);

  /* Transitions */
  --transition-fast: 120ms ease-out;
  --transition-base: 180ms ease-out;
  --transition-slow: 240ms ease-out;

  /* Layout */
  --container-max-width: 1200px;
  --container-gutter: 1.5rem;
}

/* Reduced motion overrides */
@media (prefers-reduced-motion: reduce) {
  :root {
    --transition-fast: 0ms;
    --transition-base: 0ms;
    --transition-slow: 0ms;
  }
}


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

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

html {
  margin: 0;
  padding: 0;
  scroll-behavior: smooth;
}

body {
  margin: 0;
}

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

ul[role='list'],
ol[role='list'] {
  list-style: none;
  margin: 0;
  padding: 0;
}

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

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

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

textarea {
  resize: vertical;
}

/* Remove default link underline and outline (we reintroduce focus outline explicitly) */
a {
  text-decoration: none;
  color: inherit;
}

a:focus {
  outline: none;
}


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

body {
  min-height: 100vh;
  font-family: var(--font-sans);
  font-size: var(--font-size-md);
  line-height: var(--line-height-normal);
  background-color: var(--color-background);
  color: var(--color-text);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

main {
  min-height: 60vh;
}

/* Headings: modern, performance-oriented scale */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  font-weight: 700;
  line-height: var(--line-height-tight);
  color: var(--color-neutral-900);
}

h1 {
  font-size: clamp(2.25rem, 2.5vw + 1.5rem, 3rem);
  letter-spacing: -0.03em;
  margin-bottom: var(--space-24);
}

h2 {
  font-size: clamp(1.75rem, 1.5vw + 1.2rem, 2.25rem);
  letter-spacing: -0.02em;
  margin-bottom: var(--space-20);
}

h3 {
  font-size: 1.5rem;
  margin-bottom: var(--space-16);
}

h4 {
  font-size: 1.25rem;
  margin-bottom: var(--space-12);
}

h5 {
  font-size: 1.125rem;
  margin-bottom: var(--space-8);
}

h6 {
  font-size: 1rem;
  margin-bottom: var(--space-4);
}

p {
  line-height: var(--line-height-relaxed);
  color: var(--color-text-muted);
  margin-bottom: var(--space-16);
}

strong, b {
  font-weight: 600;
  color: var(--color-neutral-900);
}

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

/* Links: energetic but clean */
a {
  color: var(--color-primary);
  font-weight: 500;
  transition: color var(--transition-base), opacity var(--transition-fast);
}

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


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

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

/* Hide focus styles when using mouse */
:focus:not(:focus-visible) {
  outline: none;
}

/* 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;
}


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

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

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

.grid {
  display: grid;
}

.grid-auto-fit {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: var(--space-24);
}

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

.mt-0 { margin-top: 0; }
.mb-0 { margin-bottom: 0; }

.mt-16 { margin-top: var(--space-16); }
.mb-16 { margin-bottom: var(--space-16); }
.mt-24 { margin-top: var(--space-24); }
.mb-24 { margin-bottom: var(--space-24); }

.px-16 {
  padding-left: var(--space-16);
  padding-right: var(--space-16);
}

.py-16 {
  padding-top: var(--space-16);
  padding-bottom: var(--space-16);
}

/* Media query helper classes for responsive tweaks can be added as needed */


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

/* Buttons: primary action focus (e.g., Add to Cart, Buy Now) */
.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.4rem;
  padding: 0.7rem 1.4rem;
  border-radius: var(--radius-full);
  font-weight: 600;
  font-size: var(--font-size-sm);
  letter-spacing: 0.03em;
  text-transform: uppercase;
  border: 1px solid transparent;
  cursor: pointer;
  transition: background-color var(--transition-base),
              color var(--transition-base),
              border-color var(--transition-base),
              box-shadow var(--transition-base),
              transform var(--transition-fast);
}

.button-primary {
  background: linear-gradient(135deg, #22c55e, #16a34a);
  color: #020617;
  box-shadow: var(--shadow-sm);
}

.button-primary:hover:not(:disabled) {
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
  filter: brightness(1.05);
}

.button-primary:active:not(:disabled) {
  transform: translateY(0);
  box-shadow: var(--shadow-xs);
}

.button-outline {
  background-color: transparent;
  color: var(--color-neutral-900);
  border-color: var(--color-border-subtle);
}

.button-outline:hover:not(:disabled) {
  border-color: var(--color-primary);
  color: var(--color-primary);
}

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

.button-ghost:hover:not(:disabled) {
  background-color: rgba(15, 23, 42, 0.7);
}

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

.button-icon {
  padding: 0.5rem;
  border-radius: var(--radius-full);
}

/* Inputs & form controls */
.input,
select,
textarea {
  width: 100%;
  padding: 0.6rem 0.8rem;
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border-subtle);
  background-color: var(--color-surface);
  color: var(--color-neutral-900);
  font-size: var(--font-size-sm);
  line-height: var(--line-height-normal);
  transition: border-color var(--transition-base),
              box-shadow var(--transition-base),
              background-color var(--transition-base);
}

.input::placeholder,
textarea::placeholder {
  color: var(--color-neutral-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);
  background-color: #020617;
}

.input[disabled],
select[disabled],
textarea[disabled] {
  opacity: 0.6;
  cursor: not-allowed;
}

label {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  font-size: var(--font-size-sm);
  color: var(--color-neutral-600);
  margin-bottom: var(--space-4);
}

/* Card: for product tiles, feature highlights, etc. */
.card {
  background: radial-gradient(circle at top left, #1e293b 0, #020617 55%);
  border-radius: var(--radius-lg);
  border: 1px solid rgba(148, 163, 184, 0.25);
  padding: var(--space-20);
  box-shadow: var(--shadow-sm);
  color: var(--color-neutral-900);
  transition: transform var(--transition-base),
              box-shadow var(--transition-base),
              border-color var(--transition-base);
}

.card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
  border-color: rgba(52, 211, 153, 0.7);
}

.card-header {
  margin-bottom: var(--space-16);
}

.card-title {
  font-size: var(--font-size-lg);
  font-weight: 600;
  margin-bottom: var(--space-8);
}

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

.card-footer {
  margin-top: var(--space-16);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

/* Badge / label (e.g., Fast shipping, Bestseller) */
.badge {
  display: inline-flex;
  align-items: center;
  padding: 0.15rem 0.55rem;
  border-radius: var(--radius-full);
  font-size: 0.7rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.badge-success {
  background-color: rgba(34, 197, 94, 0.12);
  color: var(--color-primary-soft);
}

.badge-info {
  background-color: rgba(56, 189, 248, 0.12);
  color: #7dd3fc;
}

/* Messages / alerts */
.alert {
  border-radius: var(--radius-md);
  padding: 0.75rem 1rem;
  font-size: var(--font-size-sm);
  display: flex;
  align-items: flex-start;
  gap: 0.6rem;
}

.alert-success {
  background-color: rgba(34, 197, 94, 0.12);
  color: var(--color-primary-soft);
}

.alert-warning {
  background-color: rgba(250, 204, 21, 0.12);
  color: #facc15;
}

.alert-danger {
  background-color: rgba(248, 113, 113, 0.12);
  color: #fecaca;
}


/* ==========================================================================
   Motion preferences
   ========================================================================== */

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    scroll-behavior: auto !important;
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
  }
}