:root {
    --bg:          #024530;
    --bg2:         #013826;
    --bg3:         rgba(0,0,0,0.22);
    --bg4:         rgba(0,0,0,0.28);
    --text:        #e8f5e0;
    --text2:       #a0c8a0;
    --text3:       #5a8a6a;
    --accent:      #6ee87e;
    --accent2:     #3a9e5a;
    --accent3:     #0a7050;
    --amber:       #f0b84a;
    --amber2:      #d4a030;
    --amber3:      rgba(200,136,42,0.12);
    --border:      #0a6040;
    --border2:     rgba(10,96,64,0.5);
    --pmc-bg:      #0d2b20;
    --pmc-text:    #5ecfa0;
    --arxiv-bg:    #0d2038;
    --arxiv-text:  #6aabea;
    --book-bg:     #2a1f40;
    --book-text:   #b48ef0;
    --cs-bg:       #3a2a10;
    --cs-text:     #d4a847;
    --font-body:   'Playfair Display', Georgia, serif;
    --font-ui:     'Lora', Georgia, serif;
    --font-mono:   'JetBrains Mono', 'Courier New', monospace;
  }

  * { box-sizing: border-box; margin: 0; padding: 0; }
  body { background: var(--bg); color: var(--text); font-family: var(--font-ui); font-size: 16px; line-height: 1.75; min-height: 100vh; }
  a { color: inherit; text-decoration: none; }

  /* ── NAV ── */
  nav {
    position: fixed; top: 0; left: 0; right: 0; z-index: 100;
    display: flex; justify-content: space-between; align-items: center;
    padding: 1rem clamp(1.5rem,5vw,5rem);
    background: rgba(2,69,48,0.97); border-bottom: 1px solid var(--border);
  }
  .nav-logo { font-family: var(--font-mono); font-size: 0.9rem; color: var(--accent); letter-spacing: 0.1em; text-transform: uppercase; }
  .nav-logo span { color: var(--amber); }
  nav ul { list-style: none; display: flex; align-items: center; gap: 2rem; }
  nav ul a {
    color: var(--text2); font-family: var(--font-mono);
    font-size: 0.7rem; letter-spacing: 0.08em; text-transform: uppercase;
    text-decoration: none; transition: color 0.2s;
  }
  nav ul a:hover { color: var(--amber); }
  nav ul a.nav-active { color: var(--amber); border-bottom: 1px solid var(--amber2); padding-bottom: 2px; }

  /* ── HAMBURGER ── */
  .hamburger { display: none; flex-direction: column; gap: 5px; cursor: pointer; padding: 6px 4px; background: none; border: none; z-index: 101; }
  .hamburger span { display: block; width: 26px; height: 2px; background: var(--text); border-radius: 2px; }

  /* ── MOBILE MENU ── */
  .mobile-menu { display: none; position: fixed; top: 0; left: 0; right: 0; bottom: 0; background: rgba(2,69,48,0.97); z-index: 999; flex-direction: column; align-items: center; justify-content: center; gap: 1.8rem; }
  .mobile-menu a { font-family: var(--font-mono); font-size: 1.1rem; color: var(--text); letter-spacing: 0.15em; text-transform: uppercase; text-decoration: none; }
  .mobile-menu a:hover { color: var(--accent); }
  .mobile-menu-close { position: absolute; top: 1.2rem; right: 1.4rem; background: none; border: none; color: var(--text); font-size: 1.8rem; cursor: pointer; line-height: 1; }

  /* ── LANG SIDEBAR ── */
  #lang-sidebar {
    display: none; position: fixed; right: 0; top: 50%; transform: translateY(-50%);
    z-index: 199; flex-direction: column; align-items: center; gap: 0.4rem;
    background: rgba(20,31,20,0.88); border: 1px solid var(--border);
    border-right: none; padding: 0.6rem 0.45rem; border-radius: 4px 0 0 4px;
  }
  #lang-sidebar a { display: inline-flex; cursor: pointer; }
  .lang-flag-active { opacity: 1; }
  .lang-flag-inactive { opacity: 0.45; }

  /* ── BACK LINK ── */
  .back-link {
    display: inline-block; font-family: var(--font-mono); font-size: 0.75rem;
    color: #00e5e5; letter-spacing: 0.08em; text-transform: uppercase;
    text-decoration: none; border-bottom: 1px solid #00e5e5; padding-bottom: 2px;
    transition: opacity 0.2s;
  }
  .back-link:hover { opacity: 0.7; }

  /* ── PAGE ── */
  .page { max-width: 820px; margin: 0 auto; padding: 7rem 2rem 6rem; }

  .page-tag { font-family: var(--font-mono); font-size: 0.68rem; color: var(--amber2); letter-spacing: 0.25em; text-transform: uppercase; margin-bottom: 1rem; display: flex; align-items: center; gap: 10px; }
  .page-tag::before { content: ''; display: inline-block; width: 24px; height: 1px; background: var(--amber2); }

  h1 { font-family: var(--font-body); font-size: clamp(2rem, 4vw, 2.8rem); font-weight: 400; color: #ffffff; margin-bottom: 1rem; line-height: 1.15; }
  h1 em { font-style: italic; color: var(--accent); }

  .subtitle { font-size: 1.05rem; color: var(--text2); max-width: 600px; margin-bottom: 1.5rem; line-height: 1.8; }

  .intro-box { margin-bottom: 3.5rem; padding: 1.2rem 1.5rem; border-left: 3px solid var(--amber2); background: var(--amber3); font-size: 0.95rem; color: var(--text2); line-height: 1.75; }
  .intro-box strong { color: var(--text); }

  /* ── WISSENSPFAD ── */
  .path-section { margin-bottom: 4rem; }
  .path-label { font-family: var(--font-mono); font-size: 0.68rem; letter-spacing: 0.2em; text-transform: uppercase; color: var(--amber2); margin-bottom: 1.5rem; }

  /* Desktop: Fortschrittsleiste */
  .path-chain {
    display: flex; align-items: flex-start;
    gap: 0; position: relative;
    padding-bottom: 0.5rem;
  }
  .path-node {
    display: flex; flex-direction: column; align-items: center;
    flex: 1; position: relative; cursor: pointer;
    min-width: 0;
  }
  /* Verbindungslinie zwischen Knoten */
  .path-node:not(:last-child)::after {
    content: '';
    position: absolute; top: 14px; left: 50%; right: -50%;
    height: 1px; background: var(--border);
    z-index: 0;
    transition: background 0.3s;
  }
  .path-node.passed:not(:last-child)::after { background: var(--accent3); }

  .path-node-circle {
    width: 28px; height: 28px; border-radius: 50%;
    border: 2px solid var(--border);
    background: var(--bg3);
    display: flex; align-items: center; justify-content: center;
    font-family: var(--font-mono); font-size: 0.6rem; color: var(--text3);
    position: relative; z-index: 1;
    transition: all 0.25s;
    flex-shrink: 0;
  }
  .path-node.active .path-node-circle {
    border-color: var(--accent3); color: var(--accent);
    background: rgba(10,112,80,0.3);
  }
  .path-node.amber .path-node-circle {
    border-color: var(--amber2); color: var(--amber);
    background: var(--amber3);
  }
  .path-node.current .path-node-circle {
    border-color: var(--accent); color: #fff;
    background: var(--accent3);
    box-shadow: 0 0 0 3px rgba(110,232,126,0.2);
  }
  .path-node.amber.current .path-node-circle {
    border-color: var(--amber); color: #fff;
    background: rgba(212,160,48,0.4);
    box-shadow: 0 0 0 3px rgba(240,184,74,0.2);
  }
  .path-node-label {
    font-family: var(--font-mono); font-size: 0.58rem; letter-spacing: 0.04em;
    color: var(--text3); text-align: center; margin-top: 6px;
    line-height: 1.3; max-width: 72px;
    transition: color 0.25s;
    white-space: normal;
  }
  .path-node.active .path-node-label { color: var(--text2); }
  .path-node.amber .path-node-label { color: var(--amber2); }
  .path-node.current .path-node-label { color: var(--accent); }
  .path-node.amber.current .path-node-label { color: var(--amber); }
  .path-node:hover .path-node-circle { border-color: var(--accent); }
  .path-node:hover .path-node-label { color: var(--accent); }

  /* Mobile: Akkordeon */
  .path-accordion { display: none; }
  .path-accordion-item {
    border: 1px solid var(--border);
    margin-bottom: 4px;
    background: var(--bg3);
    transition: border-color 0.2s;
  }
  .path-accordion-item.amber { border-color: var(--amber2); }
  .path-accordion-item.active-acc { border-color: var(--accent3); }
  .path-accordion-header {
    display: flex; align-items: center; gap: 12px;
    padding: 0.75rem 1rem; cursor: pointer;
    font-family: var(--font-mono); font-size: 0.72rem;
    letter-spacing: 0.06em; color: var(--text2);
    user-select: none;
  }
  .path-accordion-item.amber .path-accordion-header { color: var(--amber); }
  .path-accordion-item.active-acc .path-accordion-header { color: var(--accent); }
  .path-accordion-num {
    width: 22px; height: 22px; border-radius: 50%;
    border: 1px solid var(--border); background: var(--bg);
    display: flex; align-items: center; justify-content: center;
    font-size: 0.58rem; color: var(--text3); flex-shrink: 0;
  }
  .path-accordion-item.amber .path-accordion-num { border-color: var(--amber2); color: var(--amber); }
  .path-accordion-item.active-acc .path-accordion-num { border-color: var(--accent); color: var(--accent); background: rgba(10,112,80,0.3); }
  .path-accordion-chevron {
    margin-left: auto; font-size: 0.8rem; color: var(--text3);
    transition: transform 0.25s;
  }
  .path-accordion-item.open .path-accordion-chevron { transform: rotate(180deg); }
  .path-accordion-body {
    display: none; padding: 0 1rem 1rem;
    font-size: 0.85rem; color: var(--text2); line-height: 1.7;
  }
  .path-accordion-item.open .path-accordion-body { display: block; }
  .path-accordion-body a.acc-scroll-link {
    display: inline-block; margin-top: 0.75rem;
    font-family: var(--font-mono); font-size: 0.65rem;
    letter-spacing: 0.08em; text-transform: uppercase;
    color: var(--accent); border-bottom: 1px solid var(--accent3);
    padding-bottom: 1px; cursor: pointer;
  }
  .path-accordion-item.amber .path-accordion-body a.acc-scroll-link { color: var(--amber); border-bottom-color: var(--amber2); }

  @media (max-width: 600px) {
    .path-chain { display: none; }
    .path-accordion { display: block; }
  }

  /* ── TIMELINE ── */
  .timeline { position: relative; padding-left: 36px; }
  .timeline::before { content: ''; position: absolute; left: 10px; top: 12px; bottom: 12px; width: 1px; background: linear-gradient(to bottom, var(--accent3), var(--border2) 85%, transparent); }

  .station { margin-bottom: 4rem; position: relative; }
  .station-dot { position: absolute; left: -30px; top: 6px; width: 12px; height: 12px; border-radius: 50%; background: var(--bg); border: 2px solid var(--accent3); }
  .station-dot.amber { border-color: var(--amber2); }
  .station-dot.dim   { border-color: var(--text3); }
  .station.in-view .station-dot { background: var(--accent3); border-color: var(--accent); }
  .station.in-view .station-dot.amber { background: rgba(212,160,48,0.3); border-color: var(--amber); }

  .station-header { margin-bottom: 1.25rem; }
  .station-step { font-family: var(--font-mono); font-size: 0.68rem; letter-spacing: 0.15em; text-transform: uppercase; color: var(--accent); margin-bottom: 0.4rem; }
  .station-step.amber { color: var(--amber); }
  .station-step.dim   { color: var(--text3); }
  .station-title { font-family: var(--font-body); font-size: 1.4rem; font-weight: 400; color: #ffffff; line-height: 1.25; margin-bottom: 0.5rem; }
  .station-desc { font-size: 0.95rem; color: var(--text2); max-width: 580px; line-height: 1.75; }

  .station.highlight .station-title { animation: stationPulse 1.2s ease-out; }
  @keyframes stationPulse {
    0%   { color: var(--amber); text-shadow: 0 0 18px rgba(240,184,74,0.6); }
    60%  { color: var(--amber); text-shadow: 0 0 8px rgba(240,184,74,0.3); }
    100% { color: #ffffff; text-shadow: none; }
  }

  /* ── REF CARDS ── */
  .ref { display: flex; gap: 14px; align-items: flex-start; padding: 14px 16px; border: 1px solid var(--border); background: var(--bg3); margin-bottom: 8px; transition: border-color 0.15s, background 0.15s; cursor: pointer; }
  .ref:hover { border-color: var(--accent3); background: var(--bg4); }
  .ref-num { font-family: var(--font-mono); font-size: 0.7rem; color: var(--text3); min-width: 20px; padding-top: 2px; }
  .ref-body { flex: 1; min-width: 0; }
  .ref-title { font-size: 0.95rem; font-weight: 500; color: var(--text); margin-bottom: 3px; line-height: 1.45; font-family: var(--font-ui); }
  .ref-meta { font-size: 0.8rem; color: var(--text2); line-height: 1.55; font-family: var(--font-mono); }
  .ref-badge { font-family: var(--font-mono); font-size: 0.65rem; letter-spacing: 0.06em; text-transform: uppercase; padding: 3px 8px; white-space: nowrap; align-self: center; }
  .ref-badge.pmc   { background: var(--pmc-bg);   color: var(--pmc-text);  }
  .ref-badge.arxiv { background: var(--arxiv-bg);  color: var(--arxiv-text);}
  .ref-badge.book  { background: var(--book-bg);   color: var(--book-text); }
  .ref-badge.cs    { background: var(--cs-bg);     color: var(--cs-text);   }
  .ref-relevanz { font-size: 0.82rem; color: var(--accent); margin-top: 6px; padding-top: 6px; border-top: 1px solid rgba(10,112,80,0.25); line-height: 1.6; }
  .ref-relevanz::before { content: '→ OMN: '; color: var(--accent2); font-weight: 500; font-family: var(--font-mono); font-size: 0.72rem; }
  .ref-relevanz.amber { color: var(--amber); border-top-color: rgba(212,160,48,0.25); }
  .ref-relevanz.amber::before { color: var(--amber2); }
  .ref-ext { font-family: var(--font-mono); font-size: 0.9rem; color: var(--text3); align-self: center; flex-shrink: 0; }
  .ref:hover .ref-ext { color: var(--accent); }

  /* ── FOOTER ── */
  .page-footer { margin-top: 5rem; padding-top: 1.5rem; border-top: 1px solid var(--border); font-family: var(--font-mono); font-size: 0.7rem; color: var(--text3); display: flex; justify-content: space-between; flex-wrap: wrap; gap: 8px; }
  .page-footer a { color: var(--accent); }

  @media (min-width: 601px) { #lang-sidebar { display: flex; } }
  @media (max-width: 600px) {
    nav ul { display: none; }
    .hamburger { display: flex; }
    .page { padding: 5.5rem 1.25rem 4rem; }
    h1 { font-size: 1.7rem; }
    .ref-badge { display: none; }
  }