@property --logo-gradient-stop-1 {
  syntax: '<percentage>';
  inherits: true;
  initial-value: 0%;
}

@property --logo-gradient-stop-2 {
  syntax: '<percentage>';
  inherits: true;
  initial-value: 61%;
}

@property --logo-gradient-stop-3 {
  syntax: '<percentage>';
  inherits: true;
  initial-value: 82%;
}

@property --logo-gradient-stop-4 {
  syntax: '<percentage>';
  inherits: true;
  initial-value: 100%;
}

:root {
  /* GTA.js logo (img/logo.svg) palette with lightened blacks */
  --bg-color: #111215;
  --card-bg: #1a1c22;
  --card-elevated-bg: #22252e;
  --text-color: #f3f4f6;
  --text-muted: #a3aab8;
  --border-color: #323643;
  --gouranga-orange: rgb(255, 150, 61);
  --gouranga-gold: rgb(249, 240, 0);
  --gouranga-amber: rgb(252, 189, 35);
  --logo-gradient-stop-1: 0%;
  --logo-gradient-stop-2: 61%;
  --logo-gradient-stop-3: 82%;
  --logo-gradient-stop-4: 100%;
  --accent-color: rgb(255, 150, 61);
  --accent-hover: rgb(249, 240, 0);
  --status-done: #34d399;
  --status-todo: #f87171;
  --code-bg: #252833;
}

:root,
.button-primary {
  --logo-gradient: linear-gradient(
    90deg,
    rgb(249, 240, 0) var(--logo-gradient-stop-1),
    rgb(250, 225, 10) var(--logo-gradient-stop-2),
    rgb(252, 189, 35) var(--logo-gradient-stop-3),
    rgb(255, 150, 61) var(--logo-gradient-stop-4)
  );
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto,
    Helvetica, Arial, sans-serif;
  background-color: var(--bg-color);
  color: var(--text-color);
  line-height: 1.6;
  margin: 0;
  padding: 0;
}

a {
  color: var(--gouranga-orange);
  text-decoration: underline;
  text-underline-offset: 2px;
}

a:hover {
  color: var(--gouranga-gold);
}

.container {
  max-width: 960px;
  margin: 0 auto;
  padding: 2.5rem 1.5rem 5rem;
}

/* Header modeled after https://rich-input.netlify.app/ */
header {
  margin-bottom: 3.5rem;
  padding-bottom: 2rem;
  border-bottom: 2px solid var(--gouranga-orange);
  border-image: var(--logo-gradient) 1;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.header-top {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
}

.title-group {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  flex-wrap: wrap;
}

h1 {
  margin: 0;
  line-height: 1;
  display: flex;
  align-items: center;
}

h1 a {
  display: inline-flex;
  text-decoration: none;
  border: none;
  border-radius: 0.375rem;
  outline-offset: 6px;
}

h1 a:hover,
h1 a:focus-visible {
  outline: 1px solid rgba(255, 150, 61, 0.45);
}

h1 .logo {
  height: 3.5rem;
  width: auto;
  display: block;
}

.description {
  font-size: 1.125rem;
  color: var(--text-muted);
  margin: 0;
}

.header-actions {
  display: flex;
  gap: 0.75rem;
  align-items: center;
  flex-wrap: wrap;
}

.button {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem 1rem;
  background-color: var(--card-bg);
  color: var(--text-color);
  border: 1px solid var(--border-color);
  border-radius: 0.375rem;
  font-size: 0.875rem;
  font-weight: 600;
  text-decoration: none;
  transition: background-color 0.15s, border-color 0.15s, color 0.15s,
    filter 0.15s;
}

.button:hover {
  background-color: var(--card-elevated-bg);
  border-color: var(--gouranga-orange);
  color: var(--gouranga-gold);
}

.button-primary {
  background: var(--logo-gradient);
  color: #111215;
  border-color: var(--gouranga-orange);
  transition:
    --logo-gradient-stop-1 0.25s ease,
    --logo-gradient-stop-2 0.25s ease,
    --logo-gradient-stop-3 0.25s ease,
    --logo-gradient-stop-4 0.25s ease,
    border-color 0.15s ease,
    color 0.15s ease;
}

.button-primary:hover {
  --logo-gradient-stop-2: 35%;
  --logo-gradient-stop-3: 60%;
  background: var(--logo-gradient);
  border-color: var(--gouranga-gold);
  color: #111215;
}

.button svg {
  width: 1.15rem;
  height: 1.15rem;
  fill: currentColor;
  flex-shrink: 0;
}

/* Single-column main content */
.main-content {
  display: flex;
  flex-direction: column;
  gap: 5rem;
  min-width: 0;
}

section {
  scroll-margin-top: 2rem;
}

h2 {
  font-size: 1.5rem;
  font-weight: 800;
  margin: 0 0 0.75rem 0;
  letter-spacing: -0.015em;
  width: fit-content;
  background: var(--logo-gradient);
  -webkit-background-clip: text;
  background-clip: text;
  color: var(--gouranga-gold);
  -webkit-text-fill-color: transparent;
  text-transform: uppercase;
}

h2 a {
  color: var(--text-muted);
  -webkit-text-fill-color: var(--text-muted);
  text-decoration: none;
  font-weight: 400;
  margin-right: 0.35rem;
  opacity: 0.7;
  transition: color 0.15s, -webkit-text-fill-color 0.15s, opacity 0.15s;
}

h2 a:hover {
  color: var(--gouranga-gold);
  -webkit-text-fill-color: var(--gouranga-gold);
  opacity: 1;
}

h3 {
  font-size: 1.05rem;
  font-weight: 700;
  margin: 0 0 0.5rem 0;
  color: var(--gouranga-gold);
}

p.section-desc {
  color: var(--text-muted);
  margin-top: 0;
  margin-bottom: 1.25rem;
}

code,
kbd {
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas,
    monospace;
  font-size: 0.85em;
  background: var(--code-bg);
  padding: 0.15rem 0.4rem;
  border-radius: 0.25rem;
  color: var(--gouranga-gold);
  border: 1px solid rgba(249, 240, 0, 0.22);
}

/* Play the Demo iframe container */
.demo-frame-wrapper {
  position: relative;
  width: 100%;
  aspect-ratio: 16 / 10;
  min-height: 520px;
  background: #000;
  border: 1px solid var(--border-color);
  border-radius: 0.5rem;
  overflow: hidden;
  box-shadow: 0 16px 40px rgba(0, 0, 0, 0.65);
}

.demo-frame-wrapper iframe {
  width: 100%;
  height: 100%;
  border: 0;
  display: block;
}

.demo-fullscreen-btn {
  position: absolute;
  top: 12px;
  right: 12px;
  z-index: 30;
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.45rem 0.75rem;
  background: rgba(17, 18, 21, 0.88);
  color: var(--gouranga-gold);
  border: 1px solid var(--gouranga-orange);
  border-radius: 0.375rem;
  font-family: inherit;
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.03em;
  text-transform: uppercase;
  cursor: pointer;
  backdrop-filter: blur(4px);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.6);
  transition: background 0.15s, color 0.15s, border-color 0.15s,
    transform 0.1s;
}

.demo-fullscreen-btn:hover {
  background: var(--logo-gradient);
  color: #111215;
  border-color: var(--gouranga-gold);
  transform: translateY(-1px);
}

.demo-fullscreen-btn svg {
  width: 1rem;
  height: 1rem;
  fill: currentColor;
}

/* Implementation status grid */
.status-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 1.25rem;
}

.status-card {
  background: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: 0.5rem;
  padding: 1.25rem 1.5rem;
}

.status-card-done {
  border-top: 3px solid var(--status-done);
}

.status-card-todo {
  border-top: 3px solid var(--status-todo);
}

.status-card h3 {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 0.75rem;
}

.status-card-done h3 {
  color: var(--status-done);
}

.status-card-todo h3 {
  color: var(--status-todo);
}

.status-list {
  margin: 0;
  padding-left: 1.25rem;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  color: var(--text-color);
  font-size: 0.95rem;
}

.status-list li strong {
  color: var(--gouranga-gold);
}

/* Quick controls grid */
.controls-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(210px, 1fr));
  gap: 0.85rem;
}

.control-item {
  background: var(--card-elevated-bg);
  border: 1px solid var(--border-color);
  border-radius: 0.375rem;
  padding: 0.75rem 1rem;
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.control-action {
  font-size: 0.8rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.04em;
  font-weight: 600;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.4rem;
  flex-wrap: wrap;
}

.control-keys {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-color);
}

.control-item-todo {
  border-style: dashed;
  border-color: rgba(248, 113, 113, 0.35);
}

.control-item-todo .control-keys {
  opacity: 0.55;
}

.control-badge-todo {
  font-size: 0.65rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--status-todo);
  background: rgba(248, 113, 113, 0.14);
  border: 1px solid rgba(248, 113, 113, 0.4);
  border-radius: 999px;
  padding: 0.05rem 0.4rem;
  white-space: nowrap;
}

/* References list */
.references-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.25rem;
  margin-top: 1.25rem;
}

.ref-group {
  background: var(--card-elevated-bg);
  border: 1px solid var(--border-color);
  border-radius: 0.375rem;
  padding: 1.1rem 1.25rem;
}

.ref-group ul {
  margin: 0.5rem 0 0;
  padding-left: 1.2rem;
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
  font-size: 0.92rem;
}

footer {
  margin-top: 5rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border-color);
  font-size: 0.85rem;
  color: var(--text-muted);
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.75rem;
}