/* ============================================================
   dal-go.github.io — GitHub (Primer)-flavored landing page
   Light theme default, auto-switches to dark via prefers-color-scheme.
   Original landing-page structure: hero+diagram, why cards,
   adapter cards, quickstart, interfaces, closing.
   ============================================================ */

:root {
  /* Primer-light palette */
  --canvas-default:   #ffffff;
  --canvas-subtle:    #f6f8fa;
  --canvas-inset:     #f6f8fa;
  --canvas-overlay:   #ffffff;
  --fg-default:       #1f2328;
  --fg-muted:         #59636e;
  --fg-subtle:        #6e7781;
  --fg-on-emphasis:   #ffffff;
  --border-default:   #d1d9e0;
  --border-muted:     #d1d9e0b3;
  --border-subtle:    #1f23280f;
  --accent-fg:        #0969da;
  --accent-emphasis:  #0969da;
  --accent-subtle:    #ddf4ff;
  --success-fg:       #1a7f37;
  --success-emphasis: #1f883d;
  --attention-fg:     #9a6700;
  --attention-subtle: #fff8c5;
  --danger-fg:        #d1242f;
  --done-fg:          #8250df;
  --done-subtle:      #fbefff;

  --btn-bg:           #f6f8fa;
  --btn-bg-hover:     #eef1f4;
  --btn-border:       #d1d9e0;
  --btn-shadow:       0 1px 0 rgba(31,35,40,.04);
  --btn-primary-bg:   #1f883d;
  --btn-primary-bg-hover: #1a7f37;
  --btn-primary-border: rgba(31,35,40,.15);

  --code-bg:          #f6f8fa;
  --code-fg:          #1f2328;

  /* header is always dark, GitHub-style */
  --header-bg:        #0d1117;
  --header-fg:        #f0f6fc;
  --header-fg-muted:  #9198a1;
  --header-border:    #1f242c;

  /* code tokens (light) */
  --pl-c:  #59636e;
  --pl-k:  #cf222e;
  --pl-s:  #0a3069;
  --pl-t:  #953800;
  --pl-en: #6639ba;
  --pl-c1: #0550ae;

  --f-body: -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans", Helvetica, Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji";
  --f-mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;

  --container: 1280px;
  --radius-1: 6px;
  --radius-2: 8px;
  --radius-3: 12px;

  --shadow-sm: 0 1px 0 rgba(31,35,40,.04);
  --shadow-md: 0 3px 6px rgba(140,149,159,.15);
  --shadow-lg: 0 8px 24px rgba(140,149,159,.20);
}

@media (prefers-color-scheme: dark) {
  :root {
    --canvas-default:   #0d1117;
    --canvas-subtle:    #151b23;
    --canvas-inset:     #010409;
    --canvas-overlay:   #151b23;
    --fg-default:       #f0f6fc;
    --fg-muted:         #9198a1;
    --fg-subtle:        #6e7681;
    --fg-on-emphasis:   #ffffff;
    --border-default:   #3d444d;
    --border-muted:     #3d444db3;
    --border-subtle:    #ffffff14;
    --accent-fg:        #4493f8;
    --accent-emphasis:  #1f6feb;
    --accent-subtle:    #1f6feb1a;
    --success-fg:       #3fb950;
    --success-emphasis: #238636;
    --attention-fg:     #d29922;
    --attention-subtle: #d299221a;
    --danger-fg:        #f85149;
    --done-fg:          #ab7df8;
    --done-subtle:      #ab7df81a;

    --btn-bg:           #212830;
    --btn-bg-hover:     #2a313c;
    --btn-border:       #3d444d;
    --btn-shadow:       0 0 transparent;
    --btn-primary-bg:   #238636;
    --btn-primary-bg-hover: #2ea043;

    --code-bg:          #151b23;
    --code-fg:          #f0f6fc;

    --pl-c:  #9198a1;
    --pl-k:  #ff7b72;
    --pl-s:  #a5d6ff;
    --pl-t:  #ffa657;
    --pl-en: #d2a8ff;
    --pl-c1: #79c0ff;

    --shadow-sm: 0 0 transparent;
    --shadow-md: 0 0 transparent;
    --shadow-lg: 0 8px 24px rgba(1,4,9,.6);
  }
}

/* ============================================================
   base
   ============================================================ */
*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; }
html, body { height: 100%; }
body {
  margin: 0;
  background: var(--canvas-default);
  color: var(--fg-default);
  font-family: var(--f-body);
  font-size: 14px;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
a { color: var(--accent-fg); text-decoration: none; }
a:hover { text-decoration: underline; }
code, pre, kbd { font-family: var(--f-mono); }
::selection { background: var(--accent-subtle); color: var(--fg-default); }

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

.container {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 16px;
}
@media (min-width: 768px) {
  .container { padding: 0 24px; }
}

.octicon { vertical-align: text-bottom; flex: none; }

/* ============================================================
   AppHeader (top dark bar)
   ============================================================ */
.AppHeader {
  background: var(--header-bg);
  color: var(--header-fg);
  border-bottom: 1px solid var(--header-border);
  font-size: 14px;
  position: sticky; top: 0; z-index: 50;
}
.AppHeader-inner {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 16px;
  display: flex;
  align-items: center;
  gap: 12px;
  height: 56px;
}

.AppHeader-brand {
  display: inline-flex; align-items: center; gap: 10px;
  color: var(--header-fg);
  font-weight: 600;
  padding: 6px 8px;
  border-radius: var(--radius-1);
}
.AppHeader-brand:hover { background: #ffffff1a; text-decoration: none; }
.AppHeader-brand-mark {
  display: inline-flex; align-items: center; justify-content: center;
  width: 36px; height: 36px;
  border-radius: 50%;
  background: #ffffff;
  box-shadow:
    inset 0 0 0 1px #ffffff20,
    0 0 0 1px #00000026,
    0 0 12px -2px rgba(9,105,218,.55);
  font-family: var(--f-mono);
  font-size: 11px;
  font-weight: 800;
  line-height: 1;
  letter-spacing: -.02em;
}
.brand-dal { color: #0969da; }
.brand-go  { color: #00ADD8; }

.AppHeader-context {
  display: inline-flex; align-items: center; gap: 6px;
}
.AppHeader-context-slash {
  color: var(--header-fg-muted);
  font-size: 18px;
  font-weight: 300;
  user-select: none;
}
.AppHeader-context-item {
  display: inline-flex; align-items: center; gap: 8px;
  color: var(--header-fg);
  font-weight: 500;
  font-size: 14px;
  padding: 6px 8px;
  border-radius: var(--radius-1);
}
.AppHeader-context-item:hover { background: #ffffff1a; text-decoration: none; }

.AppHeader-nav {
  display: flex; align-items: center; gap: 2px;
  margin-left: auto;
}
.AppHeader-nav a {
  color: var(--header-fg);
  padding: 6px 10px;
  border-radius: var(--radius-1);
  font-size: 13px;
  font-weight: 500;
}
.AppHeader-nav a:hover { background: #ffffff1a; text-decoration: none; }

.AppHeader-actions { display: flex; align-items: center; gap: 8px; }
.AppHeader-actions .btn-default {
  background: #212830;
  border-color: #3d444d;
  color: var(--header-fg);
}
.AppHeader-actions .btn-default:hover { background: #2a313c; }

@media (max-width: 880px) {
  .AppHeader-inner { gap: 8px; }
  .AppHeader-nav { display: none; }
  .AppHeader-actions { margin-left: auto; }
  .AppHeader-context-item { font-size: 13px; }
}
@media (max-width: 520px) {
  .AppHeader-context { display: none; }
}

/* ============================================================
   Buttons (Primer-like)
   ============================================================ */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 5px 16px;
  height: 32px;
  background: var(--btn-bg);
  border: 1px solid var(--btn-border);
  border-radius: var(--radius-1);
  color: var(--fg-default);
  font: inherit;
  font-size: 14px;
  font-weight: 500;
  line-height: 20px;
  cursor: pointer;
  transition: background .12s ease, border-color .12s ease, color .12s ease;
  box-shadow: var(--btn-shadow);
  user-select: none;
}
.btn:hover { background: var(--btn-bg-hover); text-decoration: none; border-color: var(--border-default); }
.btn:focus-visible { outline: 2px solid var(--accent-emphasis); outline-offset: -2px; }
.btn-sm { height: 28px; padding: 3px 12px; font-size: 12px; }
.btn-primary {
  background: var(--btn-primary-bg);
  border-color: var(--btn-primary-border);
  color: #ffffff;
}
.btn-primary:hover { background: var(--btn-primary-bg-hover); color: #fff; }

/* ============================================================
   Box (Primer surface)
   ============================================================ */
.Box {
  background: var(--canvas-default);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-2);
}

/* ============================================================
   Section scaffolding
   ============================================================ */
.section { padding: 64px 0; }
@media (min-width: 768px) {
  .section { padding: 96px 0; }
}
.section-subtle {
  background: var(--canvas-subtle);
  border-top: 1px solid var(--border-default);
  border-bottom: 1px solid var(--border-default);
}

.section-head {
  margin: 0 0 40px;
  max-width: 720px;
}
.section-eyebrow {
  display: inline-block;
  font-family: var(--f-mono);
  font-size: 12px;
  letter-spacing: .04em;
  color: var(--accent-fg);
  padding: 4px 10px;
  border: 1px solid var(--border-default);
  border-radius: 2em;
  background: var(--canvas-default);
  margin-bottom: 16px;
}
.section-title {
  margin: 0 0 8px;
  font-size: 32px;
  font-weight: 600;
  line-height: 1.2;
  letter-spacing: -.01em;
  color: var(--fg-default);
}
@media (min-width: 768px) {
  .section-title { font-size: 40px; }
}
.section-kicker {
  margin: 0;
  font-size: 18px;
  color: var(--fg-muted);
  max-width: 60ch;
}

/* ============================================================
   HERO
   ============================================================ */
.hero {
  background:
    radial-gradient(800px 400px at 90% 0%, rgba(9,105,218,.10), transparent 60%),
    radial-gradient(700px 360px at 0% 100%, rgba(0,173,216,.06), transparent 60%),
    var(--canvas-default);
  padding: 64px 0 80px;
  border-bottom: 1px solid var(--border-default);
}
@media (min-width: 1012px) {
  .hero { padding: 96px 0 120px; }
}

.hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.05fr) minmax(0, 1fr);
  gap: 48px;
  align-items: center;
}
@media (max-width: 1011px) {
  .hero-grid { grid-template-columns: 1fr; gap: 40px; }
}

.hero-eyebrow {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 4px 12px;
  background: var(--accent-subtle);
  color: var(--accent-fg);
  border-radius: 2em;
  font-size: 12px;
  font-weight: 500;
  margin-bottom: 24px;
}

.hero-title {
  margin: 0;
  font-size: clamp(40px, 6.5vw, 72px);
  font-weight: 600;
  line-height: 1.05;
  letter-spacing: -.025em;
  color: var(--fg-default);
}
.hero-line { display: block; }
.hero-accent {
  background: linear-gradient(120deg, var(--accent-fg), #00ADD8);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.hero-lede {
  margin: 24px 0 24px;
  font-size: 18px;
  line-height: 1.55;
  color: var(--fg-muted);
  max-width: 56ch;
}
.hero-lede strong { color: var(--fg-default); font-weight: 600; }

.hero-cta {
  display: flex; flex-wrap: wrap; align-items: center; gap: 12px;
}
.hero-install {
  display: inline-flex; align-items: center; gap: 8px;
  height: 32px;
  padding: 0 14px;
  border: 1px solid var(--border-default);
  border-radius: var(--radius-1);
  background: var(--canvas-subtle);
  font-family: var(--f-mono);
  font-size: 12.5px;
  color: var(--fg-default);
}
.hero-install:focus { outline: 2px solid var(--accent-emphasis); outline-offset: 2px; }
.hero-install-prompt { color: var(--fg-muted); }

/* ----- diagram (Cytoscape) ----- */
.diagram { margin: 0; }
.diagram-frame {
  position: relative;
  padding: 16px;
  border: 1px solid var(--border-default);
  border-radius: var(--radius-3);
  background: var(--canvas-default);
  box-shadow: var(--shadow-lg);
  overflow: hidden;
}
.diagram-frame::before {
  content: "";
  position: absolute; inset: 0;
  background-image:
    linear-gradient(var(--border-subtle) 1px, transparent 1px),
    linear-gradient(90deg, var(--border-subtle) 1px, transparent 1px);
  background-size: 24px 24px;
  pointer-events: none;
}
.diagram-canvas {
  position: relative;
  width: 100%;
  height: 520px;
  z-index: 1;
}
@media (max-width: 600px) {
  .diagram-canvas { height: 450px; }
  .diagram-frame { padding: 8px; }
}
.diagram-fallback {
  margin: 0;
  padding: 16px;
  font-size: 14px;
  color: var(--fg-muted);
  line-height: 1.5;
}

/* ============================================================
   WHY cards
   ============================================================ */
.why-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 16px;
}
.why-card {
  padding: 24px;
  transition: border-color .15s, box-shadow .15s, transform .15s;
}
.why-card:hover {
  border-color: var(--accent-fg);
  box-shadow: var(--shadow-md);
}
.why-icon {
  width: 36px; height: 36px;
  display: grid; place-items: center;
  background: var(--accent-subtle);
  color: var(--accent-fg);
  border-radius: var(--radius-1);
  margin-bottom: 16px;
}
.why-card:nth-child(2n) .why-icon {
  background: var(--done-subtle);
  color: var(--done-fg);
}
.why-card:nth-child(3n) .why-icon {
  background: var(--attention-subtle);
  color: var(--attention-fg);
}
.why-card h3 {
  margin: 0 0 8px;
  font-size: 18px;
  font-weight: 600;
  color: var(--fg-default);
}
.why-card p {
  margin: 0;
  font-size: 14px;
  color: var(--fg-muted);
  line-height: 1.55;
}
.why-card code {
  background: rgba(101,109,118,.16);
  padding: .15em .4em;
  border-radius: 4px;
  font-size: 12px;
}

/* ============================================================
   ADAPTERS grid (cards, not list)
   ============================================================ */
.adapter-grid {
  list-style: none;
  margin: 0 0 32px;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 16px;
}
.adapter {
  display: flex; flex-direction: column;
  padding: 20px;
  text-decoration: none;
  color: var(--fg-default);
  transition: border-color .15s, box-shadow .15s, transform .15s;
  position: relative;
}
.adapter:hover {
  border-color: var(--accent-fg);
  box-shadow: var(--shadow-md);
  transform: translateY(-1px);
  text-decoration: none;
}
.adapter-kind {
  display: inline-flex; align-items: center; gap: 6px;
  font-family: var(--f-mono);
  font-size: 11px;
  letter-spacing: .04em;
  color: var(--accent-fg);
  background: var(--accent-subtle);
  padding: 2px 10px;
  border-radius: 2em;
  align-self: flex-start;
  margin-bottom: 12px;
}
.adapter h3 {
  margin: 0 0 8px;
  font-size: 18px;
  font-weight: 600;
  color: var(--accent-fg);
}
.adapter:hover h3 { text-decoration: underline; }
.adapter p {
  margin: 0 0 16px;
  font-size: 13.5px;
  color: var(--fg-muted);
  line-height: 1.55;
  flex: 1;
}
.adapter p code {
  background: rgba(101,109,118,.16);
  padding: .15em .35em;
  border-radius: 4px;
  font-size: 12px;
}
.adapter p a { color: var(--accent-fg); font-weight: 500; }
.adapter-go {
  display: block;
  font-family: var(--f-mono);
  font-size: 11px;
  color: var(--fg-subtle);
  border-top: 1px dashed var(--border-default);
  padding-top: 10px;
  word-break: break-word;
}
.adapter-core {
  border-color: var(--done-fg);
  background: linear-gradient(180deg, var(--done-subtle), transparent 60%);
}
.adapter-core .adapter-kind {
  color: var(--done-fg);
  background: var(--done-subtle);
}
.adapter-core h3 { color: var(--done-fg); }

/* Companion */
.companion {
  padding: 20px 24px;
  border-left: 4px solid var(--accent-fg);
}
.companion h3 {
  margin: 0 0 12px;
  font-size: 16px;
  font-weight: 600;
}
.companion ul {
  margin: 0; padding: 0;
  list-style: none;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 8px 24px;
}
.companion li {
  font-size: 13.5px;
  color: var(--fg-muted);
}
.companion li strong { color: var(--fg-default); }

/* ============================================================
   QUICKSTART
   ============================================================ */
.qs-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1.6fr);
  gap: 32px;
  align-items: start;
}
@media (max-width: 880px) {
  .qs-grid { grid-template-columns: 1fr; }
}
.qs-steps {
  list-style: none;
  margin: 0; padding: 0;
  display: flex; flex-direction: column; gap: 8px;
}
.qs-steps li {
  display: grid;
  grid-template-columns: 32px 1fr;
  gap: 12px;
  padding: 12px 16px;
  border: 1px solid var(--border-default);
  border-radius: var(--radius-2);
  background: var(--canvas-default);
}
.qs-step-num {
  display: grid; place-items: center;
  width: 24px; height: 24px;
  background: var(--accent-subtle);
  color: var(--accent-fg);
  font-weight: 600;
  font-size: 13px;
  border-radius: 50%;
  margin-top: 2px;
}
.qs-steps p {
  margin: 0;
  font-size: 14px;
  color: var(--fg-default);
}
.qs-steps code {
  background: rgba(101,109,118,.16);
  padding: .15em .4em;
  border-radius: 4px;
  font-size: 90%;
}

/* ============================================================
   Code block (window-chrome style)
   ============================================================ */
.codeblock {
  background: var(--canvas-default);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-2);
  overflow: hidden;
  box-shadow: var(--shadow-lg);
}
.codeblock-head {
  display: flex; align-items: center; gap: 8px;
  padding: 10px 14px;
  background: var(--canvas-subtle);
  border-bottom: 1px solid var(--border-default);
  font-size: 12px;
  color: var(--fg-muted);
}
.codeblock-dot {
  width: 10px; height: 10px;
  border-radius: 50%;
  display: inline-block;
}
.codeblock-name {
  margin-left: 8px;
  font-family: var(--f-mono);
  font-size: 12px;
  color: var(--fg-default);
}
.codeblock-lang {
  margin-left: auto;
  padding: 1px 8px;
  font-size: 11px;
  font-family: var(--f-mono);
  border: 1px solid var(--border-default);
  border-radius: 2em;
  color: var(--fg-muted);
  background: var(--canvas-default);
}
.codeblock pre {
  margin: 0;
  padding: 16px 18px;
  overflow-x: auto;
  font-size: 12.5px;
  line-height: 1.6;
  color: var(--code-fg);
  background: var(--code-bg);
}
.codeblock pre code { background: none; padding: 0; }
.codeblock pre::-webkit-scrollbar { height: 8px; }
.codeblock pre::-webkit-scrollbar-thumb { background: var(--border-default); border-radius: 999px; }

/* Code highlight tokens */
.pl-c   { color: var(--pl-c);  font-style: italic; }
.pl-k   { color: var(--pl-k); }
.pl-s   { color: var(--pl-s); }
.pl-t   { color: var(--pl-t); }
.pl-en  { color: var(--pl-en); }
.pl-c1  { color: var(--pl-c1); }

/* ============================================================
   INTERFACES
   ============================================================ */
.iface-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1.4fr);
  gap: 32px;
  align-items: start;
}
@media (max-width: 880px) {
  .iface-grid { grid-template-columns: 1fr; }
}
.iface-prose p {
  font-size: 16px;
  color: var(--fg-default);
  margin: 0 0 16px;
  line-height: 1.6;
}
.iface-prose code {
  background: rgba(101,109,118,.16);
  padding: .15em .4em;
  border-radius: 4px;
  font-size: 90%;
}
.Flash {
  display: grid;
  grid-template-columns: 16px 1fr;
  gap: 12px;
  align-items: start;
  padding: 12px 16px;
  background: var(--attention-subtle);
  border: 1px solid var(--attention-fg);
  border-radius: var(--radius-2);
  color: var(--fg-default);
  font-size: 14px;
}
.Flash .octicon { color: var(--attention-fg); margin-top: 4px; }
.Flash code {
  background: rgba(0,0,0,.06);
  padding: .12em .4em;
  border-radius: 4px;
  font-size: 90%;
}

/* ============================================================
   CLOSING
   ============================================================ */
.closing {
  background: var(--canvas-default);
  text-align: center;
  border-top: 1px solid var(--border-default);
}
.closing-inner { max-width: 720px; margin: 0 auto; }
.closing h2 {
  margin: 0 0 16px;
  font-size: clamp(28px, 4vw, 44px);
  font-weight: 600;
  letter-spacing: -.02em;
  line-height: 1.15;
}
.closing p {
  margin: 0 0 24px;
  font-size: 16px;
  color: var(--fg-muted);
}
.closing-cta {
  display: flex; justify-content: center; gap: 12px; flex-wrap: wrap;
}

/* ============================================================
   Footer
   ============================================================ */
.AppFooter {
  border-top: 1px solid var(--border-default);
  padding: 40px 0 32px;
  background: var(--canvas-subtle);
}
.AppFooter-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}
.AppFooter ul {
  display: flex; flex-wrap: wrap; gap: 18px;
  list-style: none; padding: 0; margin: 0;
  font-size: 12px;
  color: var(--fg-muted);
}
.AppFooter ul a { color: var(--accent-fg); }
.AppFooter-tag { font-size: 12px; color: var(--fg-subtle); }

/* ============================================================
   a11y
   ============================================================ */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: .001ms !important;
    transition-duration: .001ms !important;
    scroll-behavior: auto !important;
  }
}