/* ===================================================================
   Moon's AI Studio — Shared Theme
   Loaded by /, /ai/, /playground/ via <link rel="stylesheet" href="/assets/theme.css">
   Source of truth for: vars, fonts, topnav, theme toggle, responsive.

   Token architecture (3-layer, 2026-07-19 ui-ux-pro-max-skill):
     Layer 1 PRIMITIVE — raw color/font/space values
     Layer 2 SEMANTIC  — purpose-driven aliases (--bg, --accent, --surface)
     Layer 3 COMPONENT — component-specific tokens (--card-bg, --hero-title)

   Components/extensions live in /assets/css/components/*.css or page-specific style.css
   =================================================================== */

/* ----- LAYER 1: PRIMITIVE TOKENS ----- */
:root {
  /* Color scale (gray) */
  --color-gray-50:  #faf9f7;
  --color-gray-100: #f5f1ea;
  --color-gray-200: #ebe7df;
  --color-gray-300: #d8d2c4;
  --color-gray-400: #b8b0a0;
  --color-gray-500: #8a8478;
  --color-gray-600: #6b665e;
  --color-gray-700: #4a463f;
  --color-gray-800: #2a2a2a;
  --color-gray-900: #161616;
  --color-gray-950: #0f0f0f;
  --color-gray-1000: #050505;

  /* Brand accents */
  --color-red-500: #d64545;
  --color-red-300: #e88a8a;
  --color-red-700: #a83a3a;
  --color-amber-500: #d4a373;       /* audio accent */
  --color-amber-300: #e8c8a0;

  /* Status */
  --color-green-500: #5a8f6a;
  --color-amber-status-500: #c9923a;
  --color-red-status-500: #c94c4c;

  /* Typography stacks */
  --font-fraunces: 'Fraunces', Georgia, serif;
  --font-inter: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-jetbrains: 'JetBrains Mono', 'SF Mono', Consolas, monospace;

  /* Spacing scale (4-base) */
  --space-1: 4px; --space-2: 8px; --space-3: 12px; --space-4: 16px;
  --space-5: 20px; --space-6: 24px; --space-8: 32px; --space-10: 40px;
  --space-12: 48px; --space-16: 64px; --space-20: 80px;

  /* Radii */
  --radius-sm: 4px; --radius-md: 8px; --radius-lg: 12px;
  --radius-xl: 24px; --radius-full: 9999px;

  /* Motion (per states-and-variants.md) */
  --ease-standard: cubic-bezier(0.2, 0, 0, 1);
  --duration-fast: 150ms;
  --duration-base: 250ms;
  --duration-slow: 400ms;
}

/* ----- LAYER 2: SEMANTIC TOKENS (DARK) ----- */
:root[data-theme="dark"] {
  /* Surfaces */
  --bg: var(--color-gray-950);
  --bg-2: var(--color-gray-900);
  --surface: var(--color-gray-800);
  --surface-2: #202020;
  --surface-3: #262626;
  /* Borders */
  --border: var(--color-gray-800);
  --border-strong: #3a3a3a;
  /* Text */
  --text: #f5f1ea;
  --text-2: #a8a39a;
  --text-3: #6b665e;
  /* Accents */
  --accent: var(--color-red-500);
  --accent-soft: #d6454522;
  --audio-accent: var(--color-amber-500);
  /* Status */
  --success: var(--color-green-500);
  --warning: var(--color-amber-status-500);
  --danger: var(--color-red-status-500);
  /* Font aliases */
  --serif: var(--font-fraunces);
  --sans: var(--font-inter);
  --mono: var(--font-jetbrains);
  --font-display: var(--font-fraunces);
  --font-head: var(--font-fraunces);
}

/* ----- LAYER 2: SEMANTIC TOKENS (LIGHT) ----- */
:root[data-theme="light"] {
  --bg: var(--color-gray-100);
  --bg-2: var(--color-gray-200);
  --surface: #ffffff;
  --surface-2: var(--color-gray-50);
  --surface-3: #ffffff;
  --border: var(--color-gray-300);
  --border-strong: var(--color-gray-400);
  --text: #1a1a1a;
  --text-2: #5a554c;
  --text-3: var(--color-gray-500);
  --accent: var(--color-red-500);
  --accent-soft: #d6454522;
  --audio-accent: var(--color-amber-500);
  --success: #4a7558;
  --warning: #a87a2a;
  --danger: var(--color-red-700);
  --serif: var(--font-fraunces);
  --sans: var(--font-inter);
  --mono: var(--font-jetbrains);
  --font-display: var(--font-fraunces);
  --font-head: var(--font-fraunces);
}

/* ----- LAYER 3: COMPONENT TOKENS (per component-specs.md) ----- */
:root {
  /* Button */
  --button-padding-x: var(--space-4);
  --button-padding-y: var(--space-2);
  --button-height-default: 40px;
  --button-height-sm: 32px;
  --button-height-lg: 48px;
  --button-radius: var(--radius-md);
  --button-bg: var(--accent);
  --button-bg-hover: var(--color-red-700);
  --button-fg: #ffffff;

  /* Card */
  --card-padding: var(--space-6);
  --card-radius: var(--radius-lg);
  --card-bg: var(--surface);
  --card-border: 1px solid var(--border);

  /* Input */
  --input-padding-x: var(--space-4);
  --input-padding-y: var(--space-3);
  --input-border: var(--border-strong);
  --input-focus-ring: var(--accent);

  /* Music Player dock */
  --player-height: 88px;
  --player-bg: var(--surface-2);
  --player-border: 1px solid var(--border);
  --player-accent: var(--audio-accent);

  /* Hero */
  --hero-padding: var(--space-20) var(--space-10);
  --hero-title-size: clamp(48px, 8vw, 96px);
  --hero-title-weight: 300;
  --hero-title-line: 0.95;
  --hero-title-letterspacing: -0.03em;

  /* Bento grid */
  --bento-gap: var(--space-4);
  --bento-radius: var(--radius-lg);
  --bento-min-card: 240px;
}

/* ----- RESET / BASELINE ----- */
* { box-sizing: border-box; margin: 0; padding: 0; }
html, body { background: var(--bg); color: var(--text); font-family: var(--sans); font-size: 15px; line-height: 1.55; -webkit-font-smoothing: antialiased; }
body { min-height: 100vh; }

/* ----- TOP NAV ----- */
.topnav {
  position: sticky; top: 0; z-index: 100;
  display: flex; align-items: center; justify-content: space-between;
  padding: 18px 40px;
  background: var(--bg);
  border-bottom: 1px solid var(--border);
  backdrop-filter: blur(8px);
}
.brand { display: flex; align-items: baseline; gap: 10px; text-decoration: none; color: inherit; }
.brand:visited { color: inherit; }
.brand-mark {
  font-family: var(--serif);
  font-size: 22px; font-weight: 500; letter-spacing: -0.02em;
  color: var(--text);
}
.brand-mark::after { content: "·"; color: var(--accent); margin-left: 8px; }
.brand-sub {
  font-family: var(--mono);
  font-size: 11px; color: var(--text-dim);
  text-transform: uppercase; letter-spacing: 0.15em;
}
.nav-tabs { display: flex; gap: 0; }
.nav-tab {
  padding: 8px 18px;
  font-family: var(--mono);
  font-size: 11px; text-transform: uppercase; letter-spacing: 0.12em;
  color: var(--text-2);
  border-left: 1px solid var(--border);
  transition: color 0.15s, background 0.15s;
  text-decoration: none;
}
.nav-tab:last-child { border-right: 1px solid var(--border); }
.nav-tab:hover { color: var(--text); background: var(--bg-2); }
.nav-tab.active { color: var(--accent); }
.nav-tab .dot {
  display: inline-block; width: 6px; height: 6px; border-radius: 50%;
  background: var(--accent); margin-right: 6px; vertical-align: middle;
  opacity: 0; transition: opacity 0.15s;
}
.nav-tab.active .dot { opacity: 1; }

.topnav-utils { display: flex; align-items: center; gap: 8px; }

.theme-toggle,
.topnav-utils .util-btn {
  font-family: var(--mono);
  font-size: 11px; text-transform: uppercase; letter-spacing: 0.12em;
  color: var(--text-2);
  padding: 6px 10px;
  border: 1px solid var(--border);
  background: transparent;
  cursor: pointer;
  transition: all 0.15s;
}
.theme-toggle:hover,
.topnav-utils .util-btn:hover { color: var(--text); border-color: var(--border-strong); }
.topnav-utils .util-btn.danger { color: var(--text-2); }
.topnav-utils .util-btn.danger:hover { color: var(--accent); border-color: var(--accent); }

/* ----- AUTH MENU (in topnav-utils) + LOGIN OVERLAY ----- */
.auth-who {
  font-family: var(--mono);
  font-size: 10px;
  color: var(--text-3);
  text-transform: uppercase;
  letter-spacing: 0.1em;
}

.auth-overlay {
  position: fixed; inset: 0; z-index: 9999;
  background: rgba(0, 0, 0, 0.78);
  backdrop-filter: blur(8px);
  display: flex; align-items: center; justify-content: center;
}
.auth-overlay[hidden] { display: none; }

.auth-card {
  background: var(--bg-2);
  border: 1px solid var(--border-strong);
  padding: 36px 32px 28px;
  width: min(380px, 92vw);
  display: flex; flex-direction: column; gap: 14px;
  box-shadow: 0 30px 80px rgba(0, 0, 0, 0.5);
}
.auth-eyebrow {
  font-family: var(--mono);
  font-size: 10px;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.18em;
}
.auth-title {
  font-family: var(--font-head);
  font-size: 24px;
  margin: 0;
  color: var(--text);
}
.auth-sub {
  font-size: 13px;
  color: var(--text-2);
  margin: 0;
  line-height: 1.5;
}
.auth-input {
  font-family: var(--mono);
  font-size: 22px;
  letter-spacing: 0.6em;
  text-align: center;
  background: var(--bg);
  border: 1px solid var(--border-strong);
  color: var(--text);
  padding: 12px 14px;
  outline: none;
}
.auth-input:focus { border-color: var(--accent); }

.auth-msg {
  font-size: 12px;
  min-height: 16px;
  color: var(--text-3);
}
.auth-msg.err { color: var(--accent); }
.auth-msg.ok  { color: var(--success); }

.auth-btn {
  font-family: var(--mono);
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.15em;
  background: var(--accent);
  color: #fff;
  border: none;
  padding: 12px;
  cursor: pointer;
  transition: opacity 0.15s;
}
.auth-btn:hover { opacity: 0.88; }
.auth-btn:disabled { opacity: 0.5; cursor: wait; }

.auth-cancel {
  font-family: var(--mono);
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.15em;
  background: transparent;
  border: none;
  color: var(--text-3);
  cursor: pointer;
  padding: 6px;
  text-align: center;
}
.auth-cancel:hover { color: var(--text); }

/* ----- HAMBURGER (mobile only) ----- */
.hamburger-btn {
  display: none;
  font-family: var(--mono);
  font-size: 18px;
  line-height: 1;
  color: var(--text);
  background: transparent;
  border: 1px solid var(--border);
  cursor: pointer;
  width: 44px; height: 44px;
  align-items: center; justify-content: center;
  transition: border-color 0.15s, color 0.15s;
}
.hamburger-btn:hover { border-color: var(--border-strong); color: var(--accent); }
.hamburger-btn .icon-open,
.hamburger-btn .icon-close { display: inline-block; }
.hamburger-btn .icon-close { display: none; }
.hamburger-btn.open .icon-open { display: none; }
.hamburger-btn.open .icon-close { display: inline-block; }

/* ===================================================================
   MASTHEAD (shared — 2026-07-19 unified)
   Same hero block, used by /, /ai/, /playground/, /dropbox/, /wan-image/, /wan-video/,
   /3d-viewer/, /shadow/, /docs/.
   Pages provide only the text content (eyebrow / hero-title / hero-sub / hero-meta).
   =================================================================== */
.masthead {
  padding: 80px 40px 56px;
  max-width: 1280px;
  margin: 0 auto;
  border-bottom: 1px solid var(--border);
}
.masthead .eyebrow {
  font-family: var(--mono);
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.2em;
  color: var(--accent);
  margin-bottom: 24px;
  display: flex; align-items: center; gap: 12px;
}
.masthead .eyebrow::before {
  content: "";
  width: 32px;
  height: 1px;
  background: var(--accent);
  display: inline-block;
}
.masthead .hero-title {
  font-family: var(--serif);
  font-weight: 400;
  font-size: 64px;
  line-height: 1.05;
  letter-spacing: -0.02em;
  color: var(--text);
  margin: 0 0 24px;
}
.masthead .hero-title em {
  font-style: italic;
  color: var(--accent);
}
.masthead .hero-sub {
  font-size: 16px;
  line-height: 1.6;
  color: var(--text-2);
  max-width: 720px;
  margin: 0 0 28px;
}
.masthead .hero-meta {
  display: flex; gap: 32px; flex-wrap: wrap;
  font-family: var(--mono);
  font-size: 12px;
  color: var(--text-3);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}
.masthead .hero-meta b {
  color: var(--text);
  font-weight: 500;
  margin: 0 4px;
}
.masthead .hero-meta a {
  color: var(--accent);
  text-decoration: none;
}
.masthead .hero-meta a:hover { text-decoration: underline; }

@media (max-width: 900px) {
  .masthead { padding: 56px 20px 36px; }
  .masthead .hero-title { font-size: 40px; line-height: 1.08; }
  .masthead .hero-sub { font-size: 14px; }
  .masthead .hero-meta { gap: 16px; font-size: 11px; }
}
@media (max-width: 600px) {
  .masthead { padding: 40px 16px 28px; }
  .masthead .hero-title { font-size: 32px; }
}

/* ----- MOBILE TOPNAV (≤ 900px) ----- */
@media (max-width: 900px) {
  .topnav { padding: 12px 16px; flex-wrap: wrap; row-gap: 0; align-items: center; }
  .brand-sub { display: none; }
  .brand-mark { font-size: 18px; }
  .nav-tabs { display: none; width: 100%; flex-direction: column; gap: 0; }
  .topnav.nav-open .nav-tabs { display: flex; }
  .nav-tab {
    display: block; padding: 14px 16px; font-size: 12px;
    border-left: none; border-right: none; border-top: 1px solid var(--border);
    min-height: 44px;
  }
  .nav-tab:last-child { border-bottom: 1px solid var(--border); }
  .hamburger-btn { display: inline-flex; margin-left: auto; }
  .topnav-utils { margin-left: 8px; }
  .topnav-utils .util-btn,
  .theme-toggle { padding: 6px 10px; font-size: 10px; min-height: 36px; }

  /* ShadowCraft topnav uses header.top > .wrap.nav-tabs (not .topnav) */
  header.top { padding: 12px 16px; flex-wrap: wrap; row-gap: 0; align-items: center; }
  header.top .wrap.nav-tabs { display: none; width: 100%; flex-direction: column; gap: 0; }
  header.top .wrap.nav-tabs.nav-open { display: flex; }
  header.top .wrap.nav-tabs .nav-tab {
    display: block; padding: 14px 16px; font-size: 12px;
    border-left: none; border-right: none; border-top: 1px solid var(--border);
    min-height: 44px;
  }
  header.top .wrap.nav-tabs .nav-tab:last-child { border-bottom: 1px solid var(--border); }
  header.top .hamburger-btn { display: inline-flex; margin-left: auto; }
}