:root {
  --white: #ffffff; --ink: #2e3a40; --ink-soft: #5c676d; --ink-faint: #9aa6ac;
  --blue: #1f6bf0; --blue-deep: #1356cf; --mist: #f4f7fa; --line: #e7edf2;
  --serif: "Newsreader", Georgia, "Times New Roman", serif;
  --sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}
* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  background: var(--white); color: var(--ink); font-family: var(--serif);
  font-optical-sizing: auto; font-size: 18px; line-height: 1.7;
  -webkit-font-smoothing: antialiased; text-rendering: optimizeLegibility;
}
em, .it { font-style: italic; }
.accent { color: var(--blue); font-style: italic; }
a { color: var(--blue); text-decoration: none; }
a:hover { text-decoration: underline; text-underline-offset: 3px; }
a:focus-visible, button:focus-visible { outline: 3px solid var(--blue); outline-offset: 3px; border-radius: 6px; }

/* Header */
header.nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 200;
  height: 64px; display: flex; align-items: center;
  background: rgba(255,255,255,.86); backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid transparent; transition: border-color .3s ease;
}
header.nav.scrolled { border-color: var(--line); }
.nav-inner {
  position: relative; width: 100%; max-width: 1160px; margin: 0 auto; padding: 0 28px;
  display: flex; align-items: center; justify-content: space-between;
}
.brand {
  position: absolute; left: 50%; transform: translateX(-50%);
  font-family: var(--serif); font-weight: 500; font-size: 22px;
  letter-spacing: -0.01em; color: var(--ink); text-decoration: none;
}
.brand:hover { text-decoration: none; }
.brand .dot { color: var(--blue); }
.back-link { font-family: var(--sans); font-size: 14px; color: var(--ink-soft); white-space: nowrap; }
.back-link:hover { color: var(--ink); text-decoration: none; }

/* Sprachumschalter */
.lang { display: flex; align-items: center; gap: 7px; font-family: var(--sans); font-size: 13px; letter-spacing: .06em; }
.lang a { color: #b3bdc4; transition: color .2s ease; }
.lang a:hover { color: var(--ink-soft); text-decoration: none; }
.lang a.active { color: var(--blue); }
.lang .sep { color: #d9e0e5; }

/* Hero */
.hero { text-align: center; padding: 120px 28px 36px; max-width: 900px; margin: 0 auto; }
.hero-label { font-family: var(--sans); font-size: 12px; letter-spacing: .16em; text-transform: uppercase; color: var(--blue); margin-bottom: 22px; }
.hero h1 { font-family: var(--serif); font-weight: 400; font-size: clamp(30px, 5vw, 50px); line-height: 1.1; letter-spacing: -0.02em; margin: 0; }
.hero-explainer { font-family: var(--serif); font-weight: 300; font-size: clamp(18px, 2.2vw, 22px); line-height: 1.5; color: var(--ink-soft); max-width: 30ch; margin: 26px auto 0; }

/* Inhaltsspalte */
.doc { max-width: 700px; margin: 0 auto; padding: 20px 28px 0; }
.block { padding: 44px 0; border-top: 1px solid var(--line); }
.block:first-child { border-top: none; }
.kicker { font-family: var(--sans); font-size: 13px; letter-spacing: .16em; text-transform: uppercase; color: var(--blue); margin-bottom: 22px; }
.block > p { font-family: var(--serif); font-weight: 300; font-size: 18px; line-height: 1.68; color: var(--ink-soft); margin: 0 0 16px; }
.block > p:last-child { margin-bottom: 0; }
.lead-q { font-family: var(--serif); font-weight: 400; font-size: clamp(20px, 2.4vw, 25px) !important; line-height: 1.4 !important; color: var(--ink) !important; max-width: 30ch; }

/* Stand der Forschung – Blöcke */
.sci-block { padding: 22px 0; }
.sci-block + .sci-block { border-top: 1px solid var(--line); }
.sci-block h3 { font-family: var(--serif); font-weight: 600; font-size: 21px; letter-spacing: -0.01em; color: var(--ink); margin: 0; line-height: 1.25; }
.sci-ex { font-family: var(--serif); font-style: italic; font-weight: 300; font-size: 15px; color: var(--ink-faint); margin: 8px 0 14px; line-height: 1.45; }
.sci-block p:not(.sci-ex) { font-family: var(--serif); font-weight: 300; font-size: 17px; line-height: 1.7; color: var(--ink-soft); margin: 0; }

/* Abschluss */
.end { text-align: center; padding: 56px 28px 96px; }
.back-btn { display: inline-block; font-family: var(--serif); font-style: italic; font-weight: 400; font-size: clamp(22px, 3vw, 30px); letter-spacing: -0.01em; color: var(--blue); transition: color .25s ease; }
.back-btn:hover, .back-btn:focus-visible { color: var(--ink); text-decoration: none; }

/* Scroll-Reveal */
.reveal { opacity: 0; transform: translateY(20px); transition: opacity .7s cubic-bezier(.16,1,.3,1), transform .7s cubic-bezier(.16,1,.3,1); }
.reveal.in { opacity: 1; transform: none; }

/* Weicher Seitenwechsel */
#leave { position: fixed; inset: 0; z-index: 1100; background: #fff; opacity: 0; pointer-events: none; transition: opacity .5s ease; }
#leave.show { opacity: 1; pointer-events: all; }

/* Projektnummer über der Überschrift (Ziel der Intro-Animation) */
.hero-num { font-family: var(--serif); font-style: italic; font-weight: 400; font-size: clamp(34px, 6vw, 56px); line-height: 1; letter-spacing: -0.02em; color: var(--blue); margin: 0 0 18px; }
.hero-num .dot { color: var(--ink); }
body:not(.intro-done) .hero-num { visibility: hidden; }

/* Intro-Zwischenseite: große Projektnummer beim Seiteneinstieg */
#intro { position: fixed; inset: 0; z-index: 1200; background: #fff; display: grid; place-items: center; padding: 0 24px; text-align: center; }
#intro .intro-num { font-family: var(--serif); font-style: italic; font-weight: 400; font-size: clamp(76px, 22vw, 220px); line-height: 1; letter-spacing: -0.02em; color: var(--blue); opacity: 0; transform-origin: center center; will-change: transform, opacity; }
#intro .intro-num .dot { color: var(--ink); }

@media (max-width: 560px) {
  .back-link .bl-text { display: none; }
  .hero { padding-top: 104px; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; transition: none; }
  #leave { transition: none; }
  #intro { display: none; }
  body:not(.intro-done) .hero-num { visibility: visible; }
}