:root{
  /* --- Neutral base: warm, paper-like greys --- */
  --k23-white:#FFFFFF;
  --k23-paper:#FAF9F7;       /* hero / page tint */
  --k23-stone:#F5F4F2;       /* alternating section band */
  --k23-sand:#EDE9E5;        /* strongest light band */
  --k23-line-soft:#EDEAE6;   /* hairline inside cards */
  --k23-line:#E7E4E0;        /* card + section borders */
  --k23-line-strong:#C8C4BF; /* outlined buttons, dividers on dark */
  --k23-grey:#7A756F;        /* muted meta text */
  --k23-umber:#534942;       /* secondary label on tinted grounds */
  --k23-ink-body:#3C3834;    /* body copy */
  --k23-ink:#1A1816;         /* headlines, dark surfaces */
  --k23-ink-line:#34302C;    /* hairline on dark surfaces */

  /* --- Room colors: the four K23 rooms, each with a role --- */
  --k23-sky:#2D6FA3;         /* Sky · Fokusraum */
  --k23-sky-deep:#1A4870;    /* hover / pressed */
  --k23-sky-tint:#EAF0F8;    /* image placeholder ground */

  --k23-earth:#7D6E63;       /* Earth · Strategieraum */
  --k23-earth-tint:#EDE9E5;

  --k23-sun:#F5B800;         /* Sun · Atelier & Ideenraum */
  --k23-sun-text:#B38500;    /* accessible text/label version of Sun */
  --k23-sun-tint:#FFF8E1;

  --k23-wood:#3D8A57;       /* Wood · Workshopraum */
  --k23-wood-deep:#265C39;  /* hover / pressed */
  --k23-wood-tint:#EAF2EC;

  /* --- Logo colors (print mark, deeper than the web palette) --- */
  --k23-logo-blue:#134395;
  --k23-logo-yellow:#F5C400;
  --k23-logo-green:#4A8B3B;
  --k23-logo-brown:#5C4F3E;

  /* --- Semantic aliases: use these in components --- */
  --surface-page:var(--k23-white);
  --surface-raised:var(--k23-white);
  --surface-tint:var(--k23-paper);
  --surface-band:var(--k23-stone);
  --surface-band-strong:var(--k23-sand);
  --surface-inverse:var(--k23-ink);

  --text-heading:var(--k23-ink);
  --text-body:var(--k23-ink-body);
  --text-muted:var(--k23-grey);
  --text-label:var(--k23-umber);
  --text-on-inverse:var(--k23-white);
  --text-body-on-inverse:var(--k23-line-strong);
  --text-link:var(--k23-sky);
  --text-link-hover:var(--k23-sky-deep);

  --border-hairline:var(--k23-line-soft);
  --border-default:var(--k23-line);
  --border-strong:var(--k23-line-strong);
  --border-inverse:var(--k23-ink-line);

  --action-primary:var(--k23-sky);
  --action-primary-hover:var(--k23-sky-deep);
  --action-primary-text:var(--k23-white);
  --accent-highlight:var(--k23-sun);

  /* Glass surfaces (sticky header, image capsules) */
  --glass-header:rgba(255,255,255,0.88);
  --glass-capsule:rgba(255,255,255,0.92);
  --glass-on-dark:rgba(255,255,255,0.12);
  --glass-border-on-dark:rgba(255,255,255,0.45);
}