/* ============================================================
   Basis: Reset, Raster, globale Schicht (Grain, Cursor, Rail)
   ============================================================ */

*, *::before, *::after { box-sizing: border-box; }
* { margin: 0; }

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  background: var(--void);
  color: var(--text);
  font-family: var(--sans);
  font-size: var(--t-body);
  line-height: 1.618;              /* φ als Zeilenabstand */
  letter-spacing: -0.011em;
  -webkit-font-smoothing: antialiased;
  overflow-x: clip;
  min-height: 100svh;
}

img, svg, canvas, video { display: block; max-width: 100%; }
button, input { font: inherit; color: inherit; }
a { color: inherit; text-decoration: none; }

::selection { background: var(--a1); color: var(--void); }

:focus-visible {
  outline: 2px solid var(--a0);
  outline-offset: 3px;
  border-radius: var(--f3);
}

/* ---- Bildschirmlose Hilfstexte -------------------------- */
.sr-only {
  position: absolute; width: 1px; height: 1px;
  padding: 0; overflow: hidden; clip-path: inset(50%);
  white-space: nowrap; border: 0;
}

.skip {
  position: fixed; top: var(--f13); left: var(--f13);
  z-index: 999; padding: var(--f8) var(--f21);
  background: var(--a0); color: var(--void); border-radius: var(--f8);
  font: 600 var(--t-small)/1 var(--mono);
  transform: translateY(-200%);
  transition: transform var(--dur-2) var(--ease-out);
}
.skip:focus { transform: none; }

/* ============================================================
   Globale Overlays
   ============================================================ */

/* Filmkorn — SVG-Rauschen, GPU-günstig, kein Bild */
.grain {
  position: fixed; inset: -50%;
  pointer-events: none; z-index: 200;
  opacity: 0.035; mix-blend-mode: overlay;
  background-image: var(--grain-src);
  animation: grain-shift 700ms steps(1) infinite;
}
@keyframes grain-shift {
  0%   { transform: translate(0, 0); }
  20%  { transform: translate(-3%, 2%); }
  40%  { transform: translate(2%, -4%); }
  60%  { transform: translate(-2%, -2%); }
  80%  { transform: translate(4%, 3%); }
  100% { transform: translate(0, 0); }
}

/* Vignette + Scanline-Hauch */
.vignette {
  position: fixed; inset: 0; pointer-events: none; z-index: 199;
  background:
    radial-gradient(130% 100% at 50% 0%, transparent 42%, oklch(0% 0 0 / 0.55) 100%),
    repeating-linear-gradient(0deg, oklch(0% 0 0 / 0.14) 0 1px, transparent 1px 3px);
  opacity: 0.8;
}

/* ---- Cursor --------------------------------------------- */
@media (hover: hover) and (pointer: fine) {
  body.cursor-on, body.cursor-on * { cursor: none !important; }
}
.cursor-dot, .cursor-ring {
  position: fixed; top: 0; left: 0; z-index: 300;
  pointer-events: none; border-radius: 50%;
  will-change: transform;
}
.cursor-dot {
  width: var(--f5); height: var(--f5);
  background: var(--a2);
  box-shadow: 0 0 var(--f13) var(--a2);
}
.cursor-ring {
  width: var(--f34); height: var(--f34);
  border: 1px solid var(--a0);
  transition: width var(--dur-2) var(--ease-spring),
              height var(--dur-2) var(--ease-spring),
              border-color var(--dur-2), opacity var(--dur-2),
              background-color var(--dur-2);
  mix-blend-mode: difference;
}
.cursor-ring[data-state="link"] {
  width: var(--f55); height: var(--f55);
  border-color: var(--a1);
  background: oklch(72% 0.215 332.5 / 0.12);
}
.cursor-ring[data-state="drag"] {
  width: var(--f89); height: var(--f89);
  border-color: var(--a2);
}
.cursor-ring[data-state="hidden"] { opacity: 0; }

/* ---- Lesefortschritt ------------------------------------ */
.progress {
  position: fixed; top: 0; left: 0; right: 0; height: var(--f2);
  z-index: 250; transform-origin: 0 50%; transform: scaleX(0);
  background: linear-gradient(90deg, var(--a0), var(--a1), var(--a2));
}
@supports (animation-timeline: scroll()) {
  .progress {
    animation: progress-grow linear both;
    animation-timeline: scroll(root block);
  }
  @keyframes progress-grow { to { transform: scaleX(1); } }
}

/* ---- Index-Schiene (links) ------------------------------ */
.rail {
  position: fixed; left: var(--f21); top: 50%;
  transform: translateY(-50%);
  z-index: 180; display: grid; gap: var(--f13);
}
.rail a {
  display: flex; align-items: center; gap: var(--f8);
  font: 500 var(--t-micro)/1 var(--mono);
  color: var(--muted); letter-spacing: 0.1em;
  opacity: 0.45; transition: opacity var(--dur-2), color var(--dur-2);
}
.rail a::before {
  content: ""; width: var(--f13); height: var(--f1);
  background: currentColor; transition: width var(--dur-3) var(--ease-out);
}
.rail a:hover, .rail a[aria-current="true"] { opacity: 1; color: var(--a0); }
.rail a[aria-current="true"]::before { width: var(--f34); }
.rail span { opacity: 0; transition: opacity var(--dur-2); }
.rail a:hover span, .rail a[aria-current="true"] span { opacity: 1; }
@media (max-width: 1180px) { .rail { display: none; } }

/* ============================================================
   Layout
   ============================================================ */

.shell { width: min(100%, var(--f610) * 2.2); margin-inline: auto; padding-inline: var(--gutter); }

/*  Ab der Breite, ab der die Index-Schiene erscheint, braucht sie eine
 *  eigene Spur — sonst liegt sie auf der Überschrift.                  */
@media (min-width: 1181px) {
  .shell { padding-left: max(var(--gutter), var(--f144)); }
}

section.bogen {
  position: relative;
  padding-block: clamp(var(--f89), 13vw, var(--f233));
  border-top: var(--border);
}
section.bogen:first-of-type { border-top: 0; }

/* Kopfzeile eines Bogens: Nummer / Titel / Notiz */
.bogen-head {
  display: grid;
  grid-template-columns: var(--f89) minmax(0, 1fr);
  gap: var(--f21) var(--f34);
  align-items: start;
  margin-bottom: var(--f89);
}
.bogen-num {
  font: 500 var(--t-small)/1 var(--mono);
  color: var(--a0); letter-spacing: 0.18em;
  padding-top: var(--f8);
}
.bogen-title {
  font-size: var(--t-h2);
  font-weight: 620;
  line-height: 0.95;
  letter-spacing: -0.04em;
  text-wrap: balance;
}
.bogen-note {
  grid-column: 2;
  max-width: var(--measure);
  color: var(--muted);
  font-size: var(--t-lead);
  text-wrap: pretty;
}
.bogen-note code {
  font: 500 0.85em/1 var(--mono);
  color: var(--a2);
  background: var(--surface);
  padding: 0.15em 0.45em; border-radius: var(--f5);
}
@media (max-width: 720px) {
  .bogen-head { grid-template-columns: 1fr; gap: var(--f13); }
  .bogen-note { grid-column: 1; }
}

/* Karten-Raster — Fibonacci-Verhältnisse 8:13, 13:21 */
.grid { display: grid; gap: var(--f21); }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-phi { grid-template-columns: 13fr 21fr; }   /* φ-Split */
@media (max-width: 900px) {
  .grid-2, .grid-3, .grid-phi { grid-template-columns: 1fr; }
}

.card {
  position: relative;
  background: var(--abyss);
  border: var(--border);
  border-radius: var(--radius-lg);
  padding: var(--f34);
  overflow: hidden;
  isolation: isolate;
}
.card-label {
  font: 500 var(--t-micro)/1 var(--mono);
  letter-spacing: 0.14em; text-transform: uppercase;
  color: var(--muted); margin-bottom: var(--f21);
  display: flex; justify-content: space-between; gap: var(--f13);
}
.card-label b { color: var(--a0); font-weight: 500; }

/* Kleine Bauteil-Beschriftung unter Demos */
.caption {
  margin-top: var(--f13);
  font: 400 var(--t-small)/1.5 var(--mono);
  color: var(--muted);
}

/* ---- Reduzierte Bewegung -------------------------------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
  .grain { animation: none; }
}