/* ==========================================================================
   RS PHYSICS ACADEMY — design tokens
   Light academic palette: paper white, ink navy, a single warm accent.
   ========================================================================== */

:root{
  /* surfaces */
  --rsa-bg:#ffffff;
  --rsa-bg-alt:#f7f5f0;
  --rsa-bg-deep:#0b2545;
  --rsa-surface:#ffffff;
  --rsa-line:#e6e2d9;
  --rsa-line-strong:#cfc9bc;

  /* ink */
  --rsa-t1:#0d1a2b;          /* headings */
  --rsa-t2:#41505f;          /* body */
  --rsa-t3:#77828f;          /* muted */
  --rsa-tw:#ffffff;

  /* brand */
  --rsa-brand:#0b2545;       /* deep academic navy */
  --rsa-brand-soft:#eaf0f7;
  --rsa-accent:#c0871f;      /* warm accent, used sparingly */
  --rsa-accent-soft:#f8f0dd;
  --rsa-good:#146c4c;
  --rsa-good-soft:#e4f2ea;

  /* type */
  --rsa-fh:"Newsreader",Georgia,"Times New Roman",serif;
  --rsa-fb:"Inter Tight",-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,sans-serif;
  --rsa-fm:"IBM Plex Mono",ui-monospace,Menlo,Consolas,monospace;

  /* spacing */
  --rsa-sp-xs:4px;
  --rsa-sp-sm:8px;
  --rsa-sp-md:16px;
  --rsa-sp-lg:28px;
  --rsa-sp-xl:48px;
  --rsa-sp-2xl:80px;
  --rsa-sp-3xl:128px;

  /* radius */
  --rsa-r-sm:4px;
  --rsa-r-md:8px;
  --rsa-r-lg:14px;
  --rsa-r-full:9999px;

  /* shadow */
  --rsa-shadow-sm:0 1px 2px rgba(11,37,69,.05);
  --rsa-shadow-md:0 10px 28px rgba(11,37,69,.09);
  --rsa-shadow-lg:0 26px 70px rgba(11,37,69,.14);
  --rsa-shadow-glow:0 12px 26px rgba(11,37,69,.22);

  /* motion + layout */
  --rsa-ease:cubic-bezier(.22,.61,.36,1);
  --rsa-duration:.28s;
  --rsa-container:1180px;
  --rsa-nav-h:74px;

  /* graph-paper texture, a nod to physics ruled paper */
  --rsa-grid:rgba(11,37,69,.055);
}

[data-theme="dark"]{
  --rsa-bg:#0e1520;
  --rsa-bg-alt:#131c29;
  --rsa-bg-deep:#080d16;
  --rsa-surface:#16202e;
  --rsa-line:#243040;
  --rsa-line-strong:#33425a;

  --rsa-t1:#f2f5f8;
  --rsa-t2:#c3ccd7;
  --rsa-t3:#8a97a6;
  --rsa-tw:#ffffff;

  --rsa-brand:#8fb0e8;
  --rsa-brand-soft:#182642;
  --rsa-accent:#e0ae52;
  --rsa-accent-soft:#2b1c12;
  --rsa-good:#4cc191;
  --rsa-good-soft:#132b22;

  --rsa-shadow-sm:0 1px 2px rgba(0,0,0,.4);
  --rsa-shadow-md:0 6px 18px rgba(0,0,0,.45);
  --rsa-shadow-lg:0 18px 48px rgba(0,0,0,.55);
  --rsa-shadow-glow:0 10px 26px rgba(240,138,75,.25);

  --rsa-grid:rgba(126,162,236,.09);
}