/* =====================================================================
   Passiv Radar – Projektwebsite
   Stylesheet (style.css)
   ---------------------------------------------------------------------
   Dunkles "Engineering-Scope"-Designsystem. Vollständig offline-fähig:
   keine externen Fonts, keine CDNs, keine externen Ressourcen.

   Aufbau:
     1. Design-Tokens (CSS Custom Properties)
     2. Reset & Basistypografie
     3. Layout-Primitive (Container, Section, Grid)
     4. Navigationselemente (Progress-Bar, Section-Rail, Topbar)
     5. Hero
     6. Inhaltskomponenten (Karten, Stats, Figuren, Callouts)
     7. Diagramme / SVG / Bild-Frames + Lightbox
     8. Buttons ("Weiter"-Navigation)
     9. Animationen / Scroll-Reveal
    10. Footer
    11. Responsivität
    12. Barrierefreiheit (Focus, Reduced Motion)
   ===================================================================== */

/* ----- Optionale, selbst gehostete Schrift -----------------------------
   Um eine eigene Schrift einzubinden, eine .woff2-Datei nach
   assets/fonts/ legen und den folgenden Block einkommentieren.
   Ohne Datei wird automatisch der robuste System-Font-Stack genutzt
   (kein Internet, kein Download nötig).

@font-face {
  font-family: "Inter";
  src: url("../fonts/Inter-Variable.woff2") format("woff2");
  font-weight: 100 900;
  font-display: swap;
}
------------------------------------------------------------------------ */

/* =====================================================================
   1. Design-Tokens
   ===================================================================== */
:root {
  /* Farbwelt: Oszilloskop / FPGA-Floorplan -------------------------- */
  --bg:            #080b10;   /* Seitenhintergrund (fast schwarz, leicht blau) */
  --bg-soft:       #0d1219;   /* abgesetzte Flächen                          */
  --panel:         #121922;   /* Karten / Panels                            */
  --panel-2:       #18212c;   /* hervorgehobene Panels                      */
  --line:          #243040;   /* Rahmen / Trennlinien                       */
  --line-soft:     #1a2330;   /* dezente Linien                             */

  --text:          #e7eef6;   /* Primärtext                                 */
  --text-muted:    #9bacbd;   /* Sekundärtext                               */
  --text-dim:      #6b7c8f;   /* tertiär / Captions                         */

  /* Signalfarben ---------------------------------------------------- */
  --signal:        #22d3ee;   /* Cyan – "Signal", Primärakzent              */
  --signal-deep:   #0e7490;   /* dunkles Cyan                               */
  --accent:        #f5b54a;   /* Amber – Steuerung / Highlights ("Vorarbiter") */
  --doppler:       #a78bfa;   /* Violett – Doppler / Frequenzbereich (Viridis) */
  --good:          #4ade80;   /* Grün – erreichte Ziele                     */
  --warn:          #fb7185;   /* Rot/Pink – Bottlenecks / Probleme          */

  /* Glas/Glow ------------------------------------------------------- */
  --signal-glow:   rgba(34, 211, 238, 0.14);
  --accent-glow:   rgba(245, 181, 74, 0.14);

  /* Typografie ------------------------------------------------------ */
  --font-sans: "Inter", system-ui, -apple-system, "Segoe UI", Roboto,
               Helvetica, Arial, "Noto Sans", sans-serif;
  --font-mono: ui-monospace, "SF Mono", "JetBrains Mono", "Cascadia Code",
               "Roboto Mono", Consolas, "Liberation Mono", monospace;

  /* Maße ------------------------------------------------------------ */
  --maxw:        1140px;
  --maxw-narrow: 820px;
  --radius:      14px;
  --radius-sm:   8px;
  --gap:         clamp(1.2rem, 3vw, 2.2rem);
  --section-pad: clamp(4.5rem, 10vh, 8rem);

  --ease: cubic-bezier(0.22, 0.61, 0.36, 1);
}

/* =====================================================================
   2. Reset & Basistypografie
   ===================================================================== */
*, *::before, *::after { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  /* Offset, damit Anker nicht unter der Topbar verschwinden */
  scroll-padding-top: 84px;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: clamp(1rem, 0.96rem + 0.2vw, 1.075rem);
  line-height: 1.7;
  color: var(--text);
  background-color: var(--bg);
  /* Dezente Graticule-/Floorplan-Textur als Hintergrundmotiv */
  background-image:
    radial-gradient(circle at 18% -10%, rgba(34,211,238,0.08), transparent 45%),
    radial-gradient(circle at 95% 5%, rgba(167,139,250,0.07), transparent 40%),
    linear-gradient(var(--line-soft) 1px, transparent 1px),
    linear-gradient(90deg, var(--line-soft) 1px, transparent 1px);
  background-size: 100% 100%, 100% 100%, 46px 46px, 46px 46px;
  background-attachment: fixed, fixed, fixed, fixed;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
}

h1, h2, h3, h4 {
  line-height: 1.15;
  font-weight: 750;
  letter-spacing: -0.02em;
  margin: 0 0 0.6em;
  color: #fff;
}
h2 { font-size: clamp(1.9rem, 1.4rem + 2.2vw, 3rem); }
h3 { font-size: clamp(1.25rem, 1.05rem + 0.9vw, 1.6rem); letter-spacing: -0.01em; }
h4 { font-size: 1.05rem; letter-spacing: 0; }

p { margin: 0 0 1.1em; }
p:last-child { margin-bottom: 0; }

a { color: var(--signal); text-decoration: none; }
a:hover { text-decoration: underline; }

strong { color: #fff; font-weight: 650; }

code, .mono { font-family: var(--font-mono); }
code {
  background: var(--bg-soft);
  border: 1px solid var(--line);
  border-radius: 5px;
  padding: 0.1em 0.4em;
  font-size: 0.88em;
  color: var(--signal);
}

ul.clean { list-style: none; padding: 0; margin: 0; }

img { max-width: 100%; height: auto; display: block; }

/* =====================================================================
   3. Layout-Primitive
   ===================================================================== */
.container {
  width: 100%;
  max-width: var(--maxw);
  margin-inline: auto;
  padding-inline: clamp(1.2rem, 5vw, 2.5rem);
}
.container.narrow { max-width: var(--maxw-narrow); }

section.story {
  position: relative;
  padding-block: var(--section-pad);
  border-top: 1px solid var(--line-soft);
}
section.story:nth-of-type(even) { background: rgba(13, 18, 25, 0.55); }

/* Abschnittskopf: Mono-Kicker + nummerierter Index als Designmotiv */
.section-head { margin-bottom: clamp(1.8rem, 4vw, 3rem); max-width: 760px; }
.kicker {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--signal);
  margin-bottom: 1rem;
}
.kicker .idx {
  display: inline-grid;
  place-items: center;
  width: 2.1rem; height: 2.1rem;
  /* Hexagon – Nicken an Silizium/FPGA */
  clip-path: polygon(25% 5%, 75% 5%, 100% 50%, 75% 95%, 25% 95%, 0 50%);
  background: var(--signal-glow);
  border: 1px solid var(--signal-deep);
  color: var(--signal);
  font-weight: 700;
  letter-spacing: 0;
}
.section-head .lead {
  color: var(--text-muted);
  font-size: clamp(1.05rem, 1rem + 0.4vw, 1.25rem);
  margin-top: 0.4rem;
}

.grid { display: grid; gap: var(--gap); }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }
.split {
  display: grid;
  grid-template-columns: 1.05fr 0.95fr;
  gap: clamp(1.6rem, 4vw, 3.2rem);
  align-items: center;
}
.split.reverse > :first-child { order: 2; }

/* =====================================================================
   4. Navigation
   ===================================================================== */
/* Fortschrittsbalken oben */
.progress-track {
  position: fixed; inset: 0 0 auto 0; height: 3px;
  background: transparent; z-index: 60; pointer-events: none;
}
.progress-bar {
  height: 100%; width: 0;
  background: linear-gradient(90deg, var(--signal), var(--doppler));
  box-shadow: 0 0 12px var(--signal);
  transition: width 0.1s linear;
}

/* Topbar */
.topbar {
  position: fixed; inset: 0 0 auto 0; z-index: 50;
  display: flex; align-items: center; justify-content: space-between;
  padding: 0.7rem clamp(1.2rem, 5vw, 2.5rem);
  background: rgba(8, 11, 16, 0.72);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid transparent;
  transition: border-color 0.3s, background 0.3s;
}
.topbar.scrolled { border-bottom-color: var(--line); background: rgba(8,11,16,0.9); }
.brand {
  display: inline-flex; align-items: center; gap: 0.6rem;
  font-family: var(--font-mono); font-weight: 700; letter-spacing: 0.04em;
  color: #fff; font-size: 0.95rem;
}
.brand:hover { text-decoration: none; }
.brand .blip {
  width: 10px; height: 10px; border-radius: 50%;
  background: var(--signal); box-shadow: 0 0 0 0 var(--signal);
  animation: blip 2.4s var(--ease) infinite;
}
@keyframes blip {
  0%   { box-shadow: 0 0 0 0 rgba(34,211,238,0.6); }
  70%  { box-shadow: 0 0 0 10px rgba(34,211,238,0); }
  100% { box-shadow: 0 0 0 0 rgba(34,211,238,0); }
}
.topbar-meta { font-family: var(--font-mono); font-size: 0.72rem; color: var(--text-dim); letter-spacing: 0.1em; }

/* Vertikale Punkt-Navigation (Section-Rail) – Desktop */
.rail {
  position: fixed; right: 1.4rem; top: 50%; transform: translateY(-50%);
  z-index: 40; display: flex; flex-direction: column; gap: 0.85rem;
}
.rail a {
  position: relative; width: 11px; height: 11px; border-radius: 50%;
  border: 1px solid var(--line); background: transparent;
  transition: all 0.25s var(--ease);
}
.rail a::after {
  content: attr(data-label);
  position: absolute; right: 22px; top: 50%; transform: translateY(-50%);
  white-space: nowrap; font-family: var(--font-mono); font-size: 0.7rem;
  letter-spacing: 0.08em; color: var(--text-muted);
  background: var(--panel); border: 1px solid var(--line);
  padding: 0.25rem 0.55rem; border-radius: 6px;
  opacity: 0; pointer-events: none; transition: opacity 0.2s;
}
.rail a:hover { border-color: var(--signal); background: var(--signal-glow); }
.rail a:hover::after { opacity: 1; }
.rail a.active {
  border-color: var(--signal);
  background: var(--signal);
  box-shadow: 0 0 10px var(--signal);
}

/* =====================================================================
   5. Hero
   ===================================================================== */
.hero {
  position: relative; min-height: 100svh;
  display: grid; align-items: center;
  padding-block: 7rem 4rem;
  overflow: hidden;
}
/* Animierte Signal-/Korrelations-Kurve im Hintergrund */
.hero-canvas {
  position: absolute; inset: 0; width: 100%; height: 100%;
  z-index: 0; opacity: 0.5;
  mask-image: linear-gradient(to bottom, transparent, #000 25%, #000 70%, transparent);
}
.hero .container { position: relative; z-index: 1; }
.hero-tag {
  font-family: var(--font-mono); font-size: 0.8rem; letter-spacing: 0.22em;
  text-transform: uppercase; color: var(--signal);
  display: inline-flex; align-items: center; gap: 0.7rem; margin-bottom: 1.4rem;
}
.hero-tag::before {
  content: ""; width: 28px; height: 1px; background: var(--signal);
}
.hero h1 {
  font-size: clamp(2.6rem, 1.6rem + 6vw, 5.6rem);
  font-weight: 800; letter-spacing: -0.03em; line-height: 1.02;
  margin: 0 0 1.2rem;
}
.hero h1 .accent {
  background: linear-gradient(120deg, var(--signal), var(--doppler));
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.hero-sub {
  font-size: clamp(1.1rem, 1rem + 0.7vw, 1.45rem);
  color: var(--text-muted); max-width: 640px; margin-bottom: 2.4rem;
}
.hero-stats {
  display: flex; flex-wrap: wrap; gap: clamp(1.5rem, 5vw, 3.5rem);
  margin-top: 3rem; padding-top: 2rem; border-top: 1px solid var(--line-soft);
}
.hero-stat .num {
  font-family: var(--font-mono); font-size: clamp(1.5rem, 1.2rem + 1.6vw, 2.3rem);
  font-weight: 700; color: #fff; line-height: 1;
}
.hero-stat .num span { color: var(--signal); }
.hero-stat .lbl { font-size: 0.82rem; color: var(--text-dim); margin-top: 0.45rem; letter-spacing: 0.04em; }
.scroll-hint {
  position: absolute; bottom: 1.6rem; left: 50%; transform: translateX(-50%);
  font-family: var(--font-mono); font-size: 0.7rem; letter-spacing: 0.2em;
  color: var(--text-dim); text-transform: uppercase; z-index: 1;
  display: flex; flex-direction: column; align-items: center; gap: 0.5rem;
}
.scroll-hint .mouse {
  width: 22px; height: 34px; border: 1px solid var(--line); border-radius: 12px;
  position: relative;
}
.scroll-hint .mouse::after {
  content: ""; position: absolute; top: 6px; left: 50%; transform: translateX(-50%);
  width: 3px; height: 7px; border-radius: 3px; background: var(--signal);
  animation: wheel 1.8s var(--ease) infinite;
}
@keyframes wheel { 0%{opacity:0;transform:translate(-50%,0)} 40%{opacity:1} 100%{opacity:0;transform:translate(-50%,12px)} }

/* Autoren-Zeile im Hero */
.authors {
  display: flex; flex-wrap: wrap; gap: 0.5rem 1.4rem; margin-top: 2.2rem;
  font-family: var(--font-mono); font-size: 0.85rem; color: var(--text-muted);
}
.authors span { display: inline-flex; align-items: center; gap: 0.5rem; }
.authors span::before { content: "▹"; color: var(--signal); }

/* =====================================================================
   6. Inhaltskomponenten
   ===================================================================== */
.card {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: clamp(1.3rem, 3vw, 1.8rem);
  position: relative;
  transition: border-color 0.3s, transform 0.3s var(--ease);
}
.card:hover { border-color: var(--signal-deep); transform: translateY(-3px); }
.card .ico {
  width: 42px; height: 42px; border-radius: 10px;
  display: grid; place-items: center; margin-bottom: 1rem;
  background: var(--signal-glow); border: 1px solid var(--signal-deep);
}
.card .ico svg { width: 22px; height: 22px; stroke: var(--signal); }
.card h4 { color: #fff; margin-bottom: 0.5rem; }
.card p { color: var(--text-muted); font-size: 0.96rem; margin: 0; }

/* Spezialisierte Karten-Akzente */
.card.warn .ico { background: rgba(251,113,133,0.12); border-color: rgba(251,113,133,0.5); }
.card.warn .ico svg { stroke: var(--warn); }
.card.good .ico { background: rgba(74,222,128,0.12); border-color: rgba(74,222,128,0.5); }
.card.good .ico svg { stroke: var(--good); }
.card.accent .ico { background: var(--accent-glow); border-color: rgba(245,181,74,0.5); }
.card.accent .ico svg { stroke: var(--accent); }

/* Stat-Callout (große Zahlen) */
.stat {
  border: 1px solid var(--line); border-radius: var(--radius);
  background: var(--panel); padding: 1.5rem;
}
.stat .num {
  font-family: var(--font-mono); font-weight: 700; color: var(--signal);
  font-size: clamp(1.8rem, 1.4rem + 1.6vw, 2.6rem); line-height: 1;
}
.stat .lbl { color: var(--text-muted); font-size: 0.9rem; margin-top: 0.5rem; }

/* Definition / Begriffsboxen */
.def {
  border-left: 2px solid var(--signal);
  background: var(--bg-soft);
  padding: 0.9rem 1.2rem; border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  margin-bottom: 1rem;
}
.def .term { font-family: var(--font-mono); color: var(--signal); font-weight: 600; }
.def p { margin: 0.3rem 0 0; color: var(--text-muted); font-size: 0.95rem; }

/* Hervorhebungs-Callout */
.callout {
  display: flex; gap: 1rem; align-items: flex-start;
  background: linear-gradient(180deg, var(--panel-2), var(--panel));
  border: 1px solid var(--line); border-radius: var(--radius);
  padding: 1.3rem 1.5rem; margin: 1.5rem 0;
}
.callout.signal { border-color: var(--signal-deep); }
.callout .tag {
  font-family: var(--font-mono); font-size: 0.72rem; letter-spacing: 0.1em;
  text-transform: uppercase; color: var(--accent); white-space: nowrap;
  padding-top: 0.15rem;
}
.callout p { margin: 0; color: var(--text); }

/* Formel-Block */
.formula {
  font-family: var(--font-mono); font-size: 1.15rem; color: #fff;
  background: var(--bg-soft); border: 1px solid var(--line);
  border-radius: var(--radius-sm); padding: 1rem 1.3rem; overflow-x: auto;
  margin: 1rem 0;
}
.formula small { color: var(--text-dim); font-size: 0.78rem; }

/* Pipeline-Schritt-Liste (nummeriert) */
.steps { counter-reset: step; display: grid; gap: 1rem; }
.steps li { list-style: none; display: flex; gap: 1rem; align-items: flex-start; }
.steps li::before {
  counter-increment: step; content: counter(step, decimal-leading-zero);
  font-family: var(--font-mono); color: var(--signal); font-weight: 700;
  border: 1px solid var(--line); border-radius: 8px; padding: 0.25rem 0.55rem;
  font-size: 0.85rem; flex: 0 0 auto;
}
.steps li strong { display: block; }
.steps li span { color: var(--text-muted); font-size: 0.95rem; }

/* Tabelle (Hardware-Spezifikation) */
.spec-table { width: 100%; border-collapse: collapse; font-size: 0.95rem; }
.spec-table th, .spec-table td {
  text-align: left; padding: 0.7rem 0.9rem; border-bottom: 1px solid var(--line-soft);
}
.spec-table th { color: var(--text-dim); font-weight: 600; font-family: var(--font-mono);
  font-size: 0.78rem; letter-spacing: 0.06em; text-transform: uppercase; }
.spec-table td { color: var(--text); }
.spec-table td.val { font-family: var(--font-mono); color: var(--signal); text-align: right; }
.spec-table tr:hover td { background: rgba(34,211,238,0.04); }

/* =====================================================================
   7. Diagramme / Figuren / Lightbox
   ===================================================================== */
figure.fig { margin: 0; }
.frame {
  position: relative;
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1rem;
  overflow: hidden;
}
/* Eckmarken als wiederkehrendes "Graticule"-Motiv */
.frame::before, .frame::after {
  content: ""; position: absolute; width: 14px; height: 14px;
  border: 1px solid var(--signal-deep); pointer-events: none;
}
.frame::before { top: 8px; left: 8px; border-right: 0; border-bottom: 0; }
.frame::after  { bottom: 8px; right: 8px; border-left: 0; border-top: 0; }
.frame.light { background: #f7f9fb; }   /* für Schemata auf hellem Grund */
.frame.light img, .frame.light svg { mix-blend-mode: normal; }
.frame img, .frame svg { width: 100%; border-radius: 6px; }

figcaption {
  font-family: var(--font-mono); font-size: 0.78rem; color: var(--text-dim);
  margin-top: 0.8rem; letter-spacing: 0.03em; text-align: center;
}
figcaption b { color: var(--text-muted); font-weight: 600; }

/* Anklickbare Figur (Lightbox-Trigger) */
button.zoom {
  display: block; width: 100%; padding: 0; border: 0; background: none;
  cursor: zoom-in; border-radius: var(--radius);
}
button.zoom:focus-visible { outline: 2px solid var(--signal); outline-offset: 3px; }
button.zoom .frame {
  display: block; width: 100%;
}
.zoom-hint {
  position: absolute; top: 12px; right: 12px; z-index: 2;
  font-family: var(--font-mono); font-size: 0.66rem; letter-spacing: 0.08em;
  color: var(--text-muted); background: rgba(8,11,16,0.75);
  border: 1px solid var(--line); border-radius: 6px; padding: 0.25rem 0.5rem;
}

/* Lightbox */
.lightbox {
  position: fixed; inset: 0; z-index: 100; display: none;
  place-items: center; padding: 4vmin;
  background: rgba(4, 6, 9, 0.92); backdrop-filter: blur(6px);
}
.lightbox.open { display: grid; }
.lightbox img {
  max-width: 94vw; max-height: 88vh; border-radius: 10px;
  border: 1px solid var(--line); background: #fff;
}
.lightbox .lb-cap {
  position: absolute; bottom: 3vmin; left: 50%; transform: translateX(-50%);
  font-family: var(--font-mono); font-size: 0.8rem; color: var(--text-muted);
}
.lightbox .lb-close {
  position: absolute; top: 3vmin; right: 3vmin; width: 44px; height: 44px;
  border-radius: 50%; border: 1px solid var(--line); background: var(--panel);
  color: #fff; font-size: 1.4rem; cursor: pointer; line-height: 1;
}
.lightbox .lb-close:hover { border-color: var(--signal); color: var(--signal); }

/* =====================================================================
   8. Buttons / "Weiter"-Navigation
   ===================================================================== */
.btn {
  display: inline-flex; align-items: center; gap: 0.6rem;
  font-family: var(--font-mono); font-size: 0.9rem; font-weight: 600;
  letter-spacing: 0.02em; padding: 0.8rem 1.4rem; border-radius: 10px;
  border: 1px solid var(--line); background: var(--panel); color: var(--text);
  cursor: pointer; transition: all 0.25s var(--ease);
}
.btn:hover { text-decoration: none; border-color: var(--signal); color: #fff; transform: translateY(-2px); }
.btn.primary {
  background: linear-gradient(120deg, var(--signal-deep), var(--signal));
  color: #03171c; border-color: transparent; font-weight: 700;
}
.btn.primary:hover { color: #03171c; box-shadow: 0 8px 28px var(--signal-glow); }
.btn svg { width: 18px; height: 18px; }

/* "Weiter zum nächsten Kapitel" Block am Sektionsende */
.next {
  margin-top: clamp(2.5rem, 6vw, 4rem);
  display: flex; align-items: center; justify-content: space-between;
  flex-wrap: wrap; gap: 1rem;
  padding-top: 1.6rem; border-top: 1px solid var(--line-soft);
}
.next .next-label { font-family: var(--font-mono); font-size: 0.78rem; color: var(--text-dim);
  letter-spacing: 0.1em; text-transform: uppercase; }
.next .next-title { color: var(--text); font-weight: 600; }

/* =====================================================================
   9. Animationen / Scroll-Reveal
   ===================================================================== */
.reveal {
  opacity: 0; transform: translateY(28px);
  transition: opacity 0.7s var(--ease), transform 0.7s var(--ease);
  will-change: opacity, transform;
}
.reveal.in { opacity: 1; transform: none; }
/* gestaffelte Verzögerung für Gruppen */
.reveal.d1 { transition-delay: 0.08s; }
.reveal.d2 { transition-delay: 0.16s; }
.reveal.d3 { transition-delay: 0.24s; }
.reveal.d4 { transition-delay: 0.32s; }

/* =====================================================================
   10. Footer
   ===================================================================== */
footer.site {
  border-top: 1px solid var(--line); padding-block: 3.5rem 2.5rem;
  background: var(--bg-soft);
}
footer.site .grid-foot { display: grid; grid-template-columns: 1.4fr 1fr 1fr; gap: 2rem; }
footer.site h4 { color: #fff; font-family: var(--font-mono); font-size: 0.8rem;
  letter-spacing: 0.1em; text-transform: uppercase; }
footer.site ul.clean li { color: var(--text-muted); padding: 0.2rem 0; font-size: 0.92rem; }
footer.site .colophon {
  margin-top: 2.5rem; padding-top: 1.5rem; border-top: 1px solid var(--line-soft);
  font-family: var(--font-mono); font-size: 0.76rem; color: var(--text-dim);
  display: flex; justify-content: space-between; flex-wrap: wrap; gap: 0.5rem;
}

/* =====================================================================
   11. Responsivität
   ===================================================================== */
@media (max-width: 900px) {
  .grid-3, .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .split { grid-template-columns: 1fr; }
  .split.reverse > :first-child { order: 0; }
  .rail { display: none; }
  footer.site .grid-foot { grid-template-columns: 1fr; }
}
@media (max-width: 560px) {
  .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
  .hero-stats { gap: 1.4rem 2rem; }
  .topbar-meta { display: none; }
  .next { flex-direction: column; align-items: flex-start; }
}

/* =====================================================================
   12. Barrierefreiheit
   ===================================================================== */
:focus-visible { outline: 2px solid var(--signal); outline-offset: 2px; border-radius: 3px; }

.skip-link {
  position: absolute; left: -999px; top: 0; z-index: 200;
  background: var(--signal); color: #03171c; padding: 0.7rem 1.2rem;
  font-family: var(--font-mono); font-weight: 700; border-radius: 0 0 8px 0;
}
.skip-link:focus { left: 0; }

.visually-hidden {
  position: absolute !important; width: 1px; height: 1px; padding: 0; margin: -1px;
  overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap; border: 0;
}

/* Bewegung reduzieren */
@media (prefers-reduced-motion: reduce) {
  * { animation-duration: 0.001ms !important; animation-iteration-count: 1 !important;
      transition-duration: 0.001ms !important; scroll-behavior: auto !important; }
  .reveal { opacity: 1; transform: none; }
}