/* ========================================
   Variables
   ======================================== */
:root {
  /* Colors - cool, energetic palette */
  --color-background: #05070a;
  --color-surface: #0b1016;
  --color-surface-alt: #111821;
  --color-text: #f5f7fa;
  --color-text-muted: #b0bac5;

  --color-primary: #28a0ff; /* energetic cyan/blue */
  --color-primary-soft: rgba(40, 160, 255, 0.12);
  --color-primary-strong: #0076d6;

  --color-success: #28c76f;
  --color-warning: #ffbe3d;
  --color-danger: #ff4b55;

  /* Neutral grays */
  --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;

  /* Status backgrounds (subtle) */
  --color-success-soft: rgba(40, 199, 111, 0.12);
  --color-warning-soft: rgba(255, 190, 61, 0.16);
  --color-danger-soft: rgba(255, 75, 85, 0.16);

  /* Typography */
  --font-sans: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    "Helvetica Neue", Arial, "Noto Sans", sans-serif, "Apple Color Emoji",
    "Segoe UI Emoji", "Segoe UI Symbol", "Noto Color Emoji";
  --font-heading: "Inter", system-ui, -apple-system, BlinkMacSystemFont,
    "Segoe UI", Roboto, "Helvetica Neue", Arial, 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 */
  --font-size-5xl: 3rem;     /* 48px */

  --line-height-tight: 1.2;
  --line-height-snug: 1.35;
  --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: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-xl: 18px;
  --radius-full: 999px;

  /* Shadows - sleek, modern */
  --shadow-sm: 0 4px 8px rgba(0, 0, 0, 0.25);
  --shadow-md: 0 10px 30px rgba(0, 0, 0, 0.35);
  --shadow-lg: 0 20px 45px rgba(0, 0, 0, 0.45);

  /* Transitions */
  --transition-fast: 120ms ease-out;
  --transition-normal: 180ms ease-out;
  --transition-slow: 260ms ease-out;

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

/* ========================================
   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,
ol {
  margin: 0;
  padding: 0;
}

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

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

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

a {
  color: inherit;
  text-decoration: none;
}

table {
  border-collapse: collapse;
  border-spacing: 0;
}

/* Remove default focus outlines; we will handle with :focus-visible */
:focus {
  outline: none;
}

/* ========================================
   Base Styles
   ======================================== */
body {
  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);
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

main {
  min-height: 60vh;
}

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

h1 {
  font-size: clamp(2.25rem, 4vw, 3.25rem);
  margin-bottom: var(--space-4);
}

h2 {
  font-size: clamp(1.75rem, 3vw, 2.25rem);
  margin-bottom: var(--space-3);
}

h3 {
  font-size: clamp(1.4rem, 2.4vw, 1.875rem);
  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(--color-text-muted);
  margin-bottom: var(--space-1);
}

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

strong,
 b {
  font-weight: 600;
}

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

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

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

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

/* Subtle underline for inline links */
a[href] {
  text-decoration-thickness: 1px;
  text-underline-offset: 0.18em;
}

a[href]:hover {
  text-decoration: underline;
}

::selection {
  background-color: var(--color-primary-soft);
  color: var(--color-text);
}

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

/* Layout container */
.container {
  width: 100%;
  max-width: var(--container-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 helpers */
.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;
}

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

.grid-auto-fit {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: var(--space-4);
}

/* Spacing utilities (minimal set for layout) */
.mt-0 { margin-top: 0; }
.mb-0 { margin-bottom: 0; }
.mt-4 { margin-top: var(--space-4); }
.mb-4 { margin-bottom: var(--space-4); }
.mt-8 { margin-top: var(--space-8); }
.mb-8 { margin-bottom: var(--space-8); }
.pt-4 { padding-top: var(--space-4); }
.pb-4 { padding-bottom: var(--space-4); }
.pt-8 { padding-top: var(--space-8); }
.pb-8 { padding-bottom: var(--space-8); }

/* Text alignment */
.text-center { text-align: center; }
.text-right { text-align: right; }

/* 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: 0.4rem;
  padding: 0.7rem 1.4rem;
  border-radius: var(--radius-full);
  font-weight: 600;
  font-size: var(--font-size-sm);
  letter-spacing: 0.04em;
  text-transform: uppercase;
  cursor: pointer;
  border: 1px solid transparent;
  transition:
    background-color var(--transition-normal),
    color var(--transition-normal),
    border-color var(--transition-normal),
    transform var(--transition-fast),
    box-shadow var(--transition-normal);
}

.btn-primary {
  background: linear-gradient(135deg, #28a0ff, #00d0ff);
  color: #02050a;
  box-shadow: 0 12px 30px rgba(0, 160, 255, 0.35);
}

.btn-primary:hover {
  transform: translateY(-1px);
  box-shadow: 0 16px 40px rgba(0, 160, 255, 0.45);
}

.btn-primary:active {
  transform: translateY(0);
  box-shadow: 0 8px 20px rgba(0, 160, 255, 0.35);
}

.btn-outline {
  background: transparent;
  color: var(--color-text);
  border-color: rgba(255, 255, 255, 0.14);
  backdrop-filter: blur(4px);
}

.btn-outline:hover {
  background-color: rgba(255, 255, 255, 0.04);
}

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

.btn-ghost:hover {
  background-color: rgba(255, 255, 255, 0.03);
  color: var(--color-text);
}

.btn-sm {
  padding: 0.45rem 0.9rem;
  font-size: var(--font-size-xs);
}

.btn-lg {
  padding: 0.9rem 1.8rem;
  font-size: var(--font-size-md);
}

.btn:disabled,
.btn[aria-disabled="true"] {
  cursor: not-allowed;
  opacity: 0.5;
  box-shadow: none;
}

/* Form elements */
.input,
select,
textarea {
  width: 100%;
  padding: 0.7rem 0.9rem;
  border-radius: var(--radius-md);
  border: 1px solid rgba(255, 255, 255, 0.08);
  background-color: rgba(12, 16, 24, 0.96);
  color: var(--color-text);
  font-size: var(--font-size-sm);
  transition:
    border-color var(--transition-fast),
    box-shadow var(--transition-fast),
    background-color var(--transition-fast);
}

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

.input:focus-visible,
select:focus-visible,
textarea:focus-visible {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 1px var(--color-primary-soft);
  background-color: rgba(8, 12, 20, 0.98);
}

input[disabled],
select[disabled],
textarea[disabled] {
  opacity: 0.55;
  cursor: not-allowed;
}

label {
  display: inline-block;
  margin-bottom: 0.4rem;
  font-size: var(--font-size-sm);
  color: var(--color-text);
}

/* Card */
.card {
  position: relative;
  background: radial-gradient(circle at top left, #1f2933 0, #05070a 65%);
  border-radius: var(--radius-lg);
  border: 1px solid rgba(255, 255, 255, 0.04);
  padding: var(--space-4);
  box-shadow: var(--shadow-md);
  overflow: hidden;
}

.card--elevated {
  box-shadow: var(--shadow-lg);
}

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

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

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

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

/* Optional accent stripe for performance / mobility feel */
.card::before {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(120deg, rgba(40, 160, 255, 0.2), transparent 40%);
  mix-blend-mode: soft-light;
  opacity: 0.25;
  pointer-events: none;
}

/* ========================================
   Accessibility & Motion
   ======================================== */

/* Focus-visible outlines */
:where(a, button, input, select, textarea, [tabindex]):focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

/* High-contrast focus ring alternative on dark BG */
:where(.btn, .input, .card):focus-visible {
  box-shadow: 0 0 0 2px rgba(0, 0, 0, 0.7), 0 0 0 4px var(--color-primary);
}

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