/* ─────────────────────────────────────────────────────────────────────
 * Theme · electric-studio
 *   Corporate clarity. Near-black shell makes the white surface read as
 *   "stage on dark", single electric-blue accent for emphasis. Manrope
 *   for display + body (geometric corporate sans). SIGNATURE: a 4px
 *   electric-blue accent bar baked into the bottom edge of the stage,
 *   giving every chapter an instantly-recognizable corporate frame
 *   without a navbar / footer.
 *
 *   character knobs:
 *     • hero numbers   — Manrope, weight 800
 *     • rule           — 1px solid mid-gray
 *     • card           — refined-md radius (12px)
 *     • surface        — clean white + bottom electric-blue accent bar
 *     • motion         — punchy ease-out (corporate snap)
 * ───────────────────────────────────────────────────────────────────── */
:root {
  /* ─── palette ─── */
  --shell:        #0a0a0a;
  --surface:      #ffffff;
  --surface-2:    #f5f7fb;
  --surface-3:    #e8ecf3;
  --text:         #0a0a0a;
  --text-2:       #1f2530;
  --text-mute:    #5a6478;
  --text-faint:   #98a0b0;
  --rule:         #d8dde6;
  --accent:       #4361ee;             /* electric corporate blue */
  --accent-soft:  rgba(67, 97, 238, 0.10);
  --accent-glow:  rgba(67, 97, 238, 0.32);

  /* ─── fonts ─── */
  --font-display-cn: "Noto Sans SC", "Source Han Sans SC", -apple-system, sans-serif;
  --font-display-en: "Manrope", "Inter", -apple-system, sans-serif;
  --font-body:       "Manrope", "Inter", "Noto Sans SC", -apple-system, sans-serif;
  --font-mono:       "JetBrains Mono", "SF Mono", ui-monospace, monospace;
  --font-features:   "ss01", "ss02", "ss03", "cv02", "tnum";

  /* ─── motion: punchy corporate ─── */
  --dur-base:       420ms;
  --dur-slow:       700ms;
  --dur-cinematic:  1050ms;

  /* ─── design identity: corporate clarity ─── */
  --r-card:        var(--r-md);     /* 12px modern radius */
  --r-stage:       0;
  --rule-w:        1px;
  --rule-style:    solid;
  --hero-num-font:    var(--font-display-en);
  --hero-num-style:   normal;
  --hero-num-weight:  800;
  --hero-num-track:   -0.035em;
  --stage-pad-x:   110px;
  --stage-pad-y:   80px;
  --card-shadow:
    0 1px 2px rgba(20, 30, 60, 0.06),
    0 24px 56px rgba(20, 30, 60, 0.10);
  --shadow-stage:
    0 60px 160px rgba(0, 0, 0, 0.55),
    0 0 0 1px rgba(0, 0, 0, 0.06);

  /* ─── decoration: SIGNATURE — bottom electric-blue accent bar ─── */
  --surface-pattern:
    linear-gradient(0deg, #4361ee 0%, #4361ee 4px, transparent 4px, transparent 100%);
  --surface-pattern-size: 100% 100%;
  --surface-pattern-blend: normal;
  --surface-pattern-opacity: 1;
}