:root {
  /* Terminal palette */
  --ascii-black: #000000;
  --ascii-bg: #0a0e14;
  --ascii-bg-alt: #141c28;
  --ascii-bg-card: #1a2332;

  --ascii-text: #33ff33;
  --ascii-text-bright: #66ff66;
  --ascii-text-dim: #00cc00;
  --ascii-text-white: #f0f0f0;

  --ascii-cyan: #00ffff;
  --ascii-cyan-bright: #66ffff;
  --ascii-amber: #ffaa00;
  --ascii-yellow: #ffff00;
  --ascii-red: #ff0033;
  --ascii-magenta: #ff00ff;
  --ascii-success: #33ff66;
  --ascii-warning: #ffaa33;
  --ascii-error: #ff3366;

  --border-primary: var(--ascii-cyan);
  --border-secondary: var(--ascii-text);
  --border-dim: rgba(51, 255, 51, 0.3);

  --glow-color: rgba(51, 255, 51, 0.5);
  --glow-cyan: rgba(0, 255, 255, 0.5);
  --scanline-opacity: 0.05;
  --flicker-opacity: 0.97;

  --font-mono: "IBM Plex Mono", ui-monospace, "SFMono-Regular", "Courier New", monospace;
  --font-size-base: 16px;
  --line-height-base: 1.6;
  --font-size-xs: 0.75rem;
  --font-size-sm: 0.875rem;
  --font-size-md: 1rem;
  --font-size-lg: 1.25rem;
  --font-size-xl: 1.5rem;
  --font-size-2xl: 2rem;

  --space-1ch: 1ch;
  --space-2ch: 2ch;
  --space-4ch: 4ch;
  --space-6ch: 6ch;
  --space-8ch: 8ch;

  --radius-none: 0;
  --radius-soft: 6px;

  --transition-fast: 150ms ease;
  --transition-medium: 300ms ease;
  --transition-slow: 450ms ease;

  --bp-xs: 24rem;
  --bp-sm: 32rem;
  --bp-md: 48rem;
  --bp-lg: 64rem;
  --bp-xl: 80rem;
}

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

html {
  font-size: var(--font-size-base);
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  background-color: var(--ascii-bg);
  color: var(--ascii-text);
  font-family: var(--font-mono);
  font-size: var(--font-size-md);
  line-height: var(--line-height-base);
  text-rendering: optimizeLegibility;
}

body::before {
  /* Subtle CRT vignette */
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  background: radial-gradient(circle at center, rgba(0, 255, 255, 0.05), transparent 70%);
  mix-blend-mode: screen;
  z-index: 1;
}

/* T107: Links distinguishable without color alone */
a {
  color: var(--ascii-cyan);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 2px;
  transition: color var(--transition-fast), text-shadow var(--transition-fast), text-decoration-thickness var(--transition-fast);
}

a:hover,
a:focus {
  color: var(--ascii-cyan-bright);
  text-shadow: 0 0 8px var(--glow-cyan);
  text-decoration-thickness: 2px;
}

p {
  margin: 0 0 var(--space-4ch);
}

ul,
ol {
  margin: 0 0 var(--space-4ch);
  padding-left: var(--space-4ch);
}

code,
pre {
  font-family: var(--font-mono);
  font-size: var(--font-size-sm);
  color: var(--ascii-text-bright);
}

pre {
  margin: 0;
  overflow-x: auto;
}

img {
  max-width: 100%;
  height: auto;
}

button {
  font-family: var(--font-mono);
  font-size: var(--font-size-sm);
  cursor: pointer;
  background: transparent;
  color: inherit;
}

/* T096, T108: Visible focus indicators for keyboard navigation */
button:focus-visible,
a:focus-visible,
input:focus-visible,
select:focus-visible,
textarea:focus-visible {
  outline: 3px solid var(--ascii-yellow);
  outline-offset: 3px;
  box-shadow: 0 0 0 6px rgba(255, 255, 0, 0.2);
}

/* Ensure focus indicators are always visible */
*:focus-visible {
  outline: 2px solid var(--ascii-cyan);
  outline-offset: 2px;
}

::selection {
  background: rgba(0, 255, 255, 0.3);
  color: var(--ascii-text-white);
}

.page {
  position: relative;
  z-index: 2; /* Keeps content above global CRT overlay */
}

.layout-container {
  margin-inline: auto;
  padding-block: var(--space-4ch);
}

.skip-link {
  position: absolute;
  left: -9999px;
  top: var(--space-2ch);
  background: var(--ascii-bg-card);
  border: 1px solid var(--ascii-cyan);
  padding: var(--space-1ch) var(--space-2ch);
  color: var(--ascii-text-white);
  z-index: 100;
}

.skip-link:focus {
  left: var(--space-2ch);
}

.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;
}

.ascii-border-sample {
  /* Helper class for visualizing border sets while building components */
  white-space: pre;
  font-size: var(--font-size-sm);
  color: var(--ascii-text-dim);
  margin-bottom: var(--space-4ch);
}

/* T017-T019: Layout utility classes */

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

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

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

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

.gap-1 {
  gap: var(--space-1ch);
}

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

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

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

.gap-8 {
  gap: var(--space-8ch);
}

/* Flexbox utilities */
.flex {
  display: flex;
}

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

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

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

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

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

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

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

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

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

/* Spacing utilities */
.m-0 {
  margin: 0;
}

.mt-2 {
  margin-top: var(--space-2ch);
}

.mt-4 {
  margin-top: var(--space-4ch);
}

.mt-6 {
  margin-top: var(--space-6ch);
}

.mb-2 {
  margin-bottom: var(--space-2ch);
}

.mb-4 {
  margin-bottom: var(--space-4ch);
}

.mb-6 {
  margin-bottom: var(--space-6ch);
}

.mx-auto {
  margin-inline: auto;
}

.p-2 {
  padding: var(--space-2ch);
}

.p-4 {
  padding: var(--space-4ch);
}

.px-2 {
  padding-inline: var(--space-2ch);
}

.px-4 {
  padding-inline: var(--space-4ch);
}

.py-2 {
  padding-block: var(--space-2ch);
}

.py-4 {
  padding-block: var(--space-4ch);
}

/* T026-T030: ASCII Border System */
.ascii-box {
  position: relative;
  border: 2px solid var(--border-primary);
  padding: var(--space-4ch);
  background-color: var(--ascii-bg-card);
  box-shadow: 0 0 20px rgba(0, 255, 255, 0.08);
}

.ascii-box-thin {
  border: 1px solid var(--border-secondary);
  padding: var(--space-2ch);
}

.ascii-box-double {
  border: 3px double var(--ascii-cyan);
  padding: var(--space-4ch);
  box-shadow: 0 0 24px rgba(0, 255, 255, 0.12);
}

.ascii-divider {
  text-align: center;
  color: var(--ascii-text-dim);
  margin-block: var(--space-6ch);
  position: relative;
}

.ascii-divider::before {
  content: "────────────────────────────────────────";
  display: block;
  letter-spacing: 0.1ch;
}

/* T031-T034: Terminal Color Themes */
:root[data-theme="green"],
.theme-green {
  --theme-primary: var(--ascii-text);
  --theme-bright: var(--ascii-text-bright);
  --theme-dim: var(--ascii-text-dim);
  --theme-accent: var(--ascii-success);
}

:root[data-theme="amber"],
.theme-amber {
  --theme-primary: var(--ascii-amber);
  --theme-bright: var(--ascii-yellow);
  --theme-dim: #cc8800;
  --theme-accent: var(--ascii-warning);
}

:root[data-theme="blue"],
.theme-blue {
  --theme-primary: var(--ascii-cyan);
  --theme-bright: var(--ascii-cyan-bright);
  --theme-dim: #0099cc;
  --theme-accent: #00aaff;
}

/* T035-T036: IBM Plex Mono font import */
@import url('https://fonts.googleapis.com/css2?family=IBM+Plex+Mono:wght@400;500;700&display=swap');

/* T037-T040: Code and terminal text styling */
code {
  background-color: rgba(0, 255, 0, 0.08);
  border: 1px solid var(--border-dim);
  padding: 0.1ch 0.4ch;
  border-radius: 2px;
  font-size: 0.9em;
}

pre {
  border: 1px solid var(--border-secondary);
  background-color: rgba(0, 0, 0, 0.6);
  padding: var(--space-2ch);
  overflow-x: auto;
  box-shadow: 0 0 12px rgba(0, 255, 255, 0.05);
}

pre code {
  background: transparent;
  border: none;
  padding: 0;
}

.terminal-text {
  font-family: var(--font-mono);
  color: var(--ascii-text-bright);
  background-color: rgba(0, 0, 0, 0.8);
  padding: var(--space-1ch) var(--space-2ch);
  border-left: 2px solid var(--ascii-text);
  letter-spacing: 0.05ch;
}

ul.ascii-list,
ol.ascii-list {
  list-style: none;
  padding-left: var(--space-4ch);
}

ul.ascii-list li::before {
  content: "▸ ";
  color: var(--ascii-cyan);
  margin-left: calc(-1 * var(--space-4ch));
  padding-right: var(--space-1ch);
}

ol.ascii-list {
  counter-reset: ascii-counter;
}

ol.ascii-list li {
  counter-increment: ascii-counter;
}

ol.ascii-list li::before {
  content: "[" counter(ascii-counter) "] ";
  color: var(--ascii-cyan);
  margin-left: calc(-1 * var(--space-4ch));
  padding-right: var(--space-1ch);
}

/* T102: ARIA live region for dynamic content updates */
[aria-live="polite"],
[aria-live="assertive"] {
  position: relative;
}

.visually-hidden-but-announced {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}