/* app-header.css — cmd-bar design (plateau-3d-app)
 * Replaces legacy .app-header with .cmd-bar (48px sticky command bar).
 */

/* ============================================================
   DESIGN TOKENS (scoped to this file — fallback if root not set)
   ============================================================ */
:root {
  --bg-deep: #0a0e16;
  --bg-elev: #11161e;
  --bg-elev-2: #181f2b;
  --text: #e8ecf2;
  --text-mu: #a8b0bd;
  --text-fade: #6b7280;
  --accent: #6db8ff;
  --accent-bright: #92caff;
  --accent-deep: #3b82f6;
  --border: rgba(255, 255, 255, 0.08);
  --border-strong: rgba(255, 255, 255, 0.18);
  --hover-bg: rgba(255, 255, 255, 0.06);
  --active-bg: rgba(255, 255, 255, 0.10);
  --focus-ring: 0 0 0 2px var(--accent-bright);
  --font-body: "Zen Kaku Gothic New", system-ui, sans-serif;
  --font-mono: "JetBrains Mono", "Menlo", monospace;
  --container-pad: clamp(20px, 4vw, 32px);
}

/* ============================================================
   SKIP LINK
   ============================================================ */
.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  background: var(--accent);
  color: var(--bg-deep);
  padding: 8px 16px;
  font-weight: 600;
  z-index: 200;
}
.skip-link:focus { left: 0; }

/* ============================================================
   CMD-BAR
   ============================================================ */
.cmd-bar {
  position: sticky;
  top: 0;
  z-index: 100;
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  height: 48px;
  padding: 0 var(--container-pad);
  background: rgba(10, 14, 22, 0.80);
  backdrop-filter: blur(12px) saturate(140%);
  -webkit-backdrop-filter: blur(12px) saturate(140%);
  border-bottom: 1px solid var(--border);
  font-family: var(--font-body);
}

.cmd-bar__brand {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  text-decoration: none;
  color: var(--text);
  font-weight: 600;
  font-size: 13px;
  letter-spacing: 0.01em;
  transition: color 0.15s;
}
.cmd-bar__brand:hover { color: var(--accent-bright); }
.cmd-bar__brand:focus-visible {
  outline: none;
  box-shadow: var(--focus-ring);
  border-radius: 4px;
}

.cmd-bar__mark {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--accent);
  display: inline-block;
  flex-shrink: 0;
  animation: pulse 3s ease-in-out infinite;
}
@keyframes pulse {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.6; transform: scale(0.85); }
}
@media (prefers-reduced-motion: reduce) {
  .cmd-bar__mark { animation: none; }
}

.cmd-bar__nav {
  display: flex;
  align-items: center;
  gap: 4px;
  justify-self: center;
}

.cmd-tab {
  display: inline-flex;
  align-items: center;
  height: 32px;
  padding: 0 14px;
  font-size: 13px;
  font-weight: 500;
  color: var(--text-mu);
  text-decoration: none;
  border-radius: 999px;
  transition: color 0.15s, background 0.15s;
  cursor: pointer;
}
.cmd-tab:hover {
  color: var(--text);
  background: var(--hover-bg);
}
.cmd-tab[aria-current="page"] {
  color: var(--text);
  background: var(--active-bg);
}
.cmd-tab[data-tab="play"] {
  background: var(--accent);
  color: var(--bg-deep);
  font-weight: 600;
}
.cmd-tab[data-tab="play"]:hover {
  background: var(--accent-bright);
}
.cmd-tab:focus-visible {
  outline: none;
  box-shadow: var(--focus-ring);
}

.cmd-bar__lang {
  display: inline-flex;
  gap: 2px;
  justify-self: end;
  padding: 2px;
  border: 1px solid var(--border);
  border-radius: 6px;
}
.lang-pill {
  background: transparent;
  border: none;
  color: var(--text-mu);
  padding: 4px 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.06em;
  border-radius: 4px;
  cursor: pointer;
  transition: all 0.15s;
}
.lang-pill[aria-pressed="true"] {
  background: var(--active-bg);
  color: var(--text);
}
.lang-pill:hover { color: var(--text); }
.lang-pill:focus-visible {
  outline: none;
  box-shadow: var(--focus-ring);
}

/* Mobile */
@media (max-width: 640px) {
  .cmd-bar { grid-template-columns: auto 1fr auto; gap: 8px; padding: 0 12px; }
  .cmd-bar__name { display: none; }
  .cmd-tab { padding: 0 10px; font-size: 12px; height: 28px; }
}

/* ============================================================
   DATA-PAGE SECTION VISIBILITY
   ============================================================ */
body[data-page="play"]     [data-show]:not([data-show~="play"])     { display: none; }
body[data-page="overview"] [data-show]:not([data-show~="overview"]) { display: none; }
body[data-page="board"]    [data-show]:not([data-show~="board"])    { display: none; }

/* ============================================================
   PLAY-BANNER
   ============================================================ */
.play-banner {
  padding: 48px 0 32px;
  background: var(--bg-elev);
  border-bottom: 1px solid var(--border);
}
.play-banner .container {
  max-width: var(--container-max, 1100px);
  margin: 0 auto;
  padding: 0 var(--container-pad);
}
.play-banner__kicker {
  display: block;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.1em;
  color: var(--accent);
  margin-bottom: 12px;
}
.play-banner__title {
  font-size: clamp(20px, 3vw, 28px);
  font-weight: 700;
  color: var(--text);
  margin: 0 0 12px;
}
.play-banner__lead {
  color: var(--text-mu);
  font-size: 15px;
  margin: 0;
  max-width: 600px;
}

/* ============================================================
   HOWTO CTA
   ============================================================ */
.howto-cta {
  display: flex;
  justify-content: center;
  margin-top: 32px;
}