/* Literature Review Assistant – Landingpage
   Schriften bewusst ohne Google Fonts (DSGVO): System-Serifen und -Sans. */

:root {
  --bg: #FFFFFF;
  --bg-alt: #F7F8FA;
  --ink: #1B1F2A;
  --ink-soft: #4A5162;
  --ink-mute: #6B7283;
  --rule: #DDE1E8;
  --rule-strong: #1B1F2A;
  --accent: #2F6FED;
  --accent-dark: #1F56C7;
  --accent-tint: #EAF1FE;
  --warn: #9A5B00;
  --warn-tint: #FFF4E0;

  --serif: "Iowan Old Style", "Charter", "Bitstream Charter", "Sitka Text", Cambria, Georgia, serif;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --mono: ui-monospace, "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;

  --radius: 10px;
  --wrap: 1120px;
  --gutter: 20px;
}

*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 17px/1.65 var(--sans);
  overflow-x: hidden;
}
img, svg { display: block; max-width: 100%; }
a { color: var(--accent); text-underline-offset: 3px; }
a:hover { color: var(--accent-dark); }
:focus-visible { outline: 3px solid var(--accent); outline-offset: 3px; border-radius: 4px; }

h1, h2, h3 { font-family: var(--serif); font-weight: 600; line-height: 1.2; margin: 0; letter-spacing: -0.01em; }
h1 { font-size: clamp(2.2rem, 5.2vw, 3.6rem); }
h2 { font-size: clamp(1.6rem, 3.4vw, 2.3rem); }
h3 { font-size: 1.2rem; }
p { margin: 0 0 1em; }
i { font-style: italic; }

.skip { position: absolute; left: -999px; top: 8px; background: var(--ink); color: #fff; padding: 8px 14px; border-radius: 6px; z-index: 100; }
.skip:focus { left: 8px; }

.wrap { max-width: var(--wrap); margin: 0 auto; padding: 0 var(--gutter); }
.narrow { max-width: 820px; }

/* Header */
.site-header { position: sticky; top: 0; z-index: 20; background: rgba(255,255,255,.92); backdrop-filter: saturate(1.4) blur(8px); border-bottom: 1px solid var(--rule); }
.header-inner { display: flex; align-items: center; gap: 24px; height: 64px; }
.brand { display: flex; align-items: center; gap: 10px; color: var(--ink); text-decoration: none; font-family: var(--serif); font-weight: 600; font-size: 1.05rem; }
.brand-mark { width: 28px; height: 28px; flex: none; }
.brand-mark rect { fill: var(--accent); }
.brand-mark circle, .brand-mark path { fill: none; stroke: #fff; stroke-width: 3; stroke-linecap: round; }
.nav { display: flex; gap: 22px; margin-left: auto; }
.nav a { color: var(--ink-soft); text-decoration: none; font-size: .95rem; }
.nav a:hover { color: var(--accent); }

/* Buttons */
.btn {
  display: inline-flex; align-items: center; justify-content: center; min-height: 48px; padding: 0 24px;
  background: var(--accent); color: #fff; border: 0; border-radius: 999px;
  font: 600 1rem/1 var(--sans); cursor: pointer; text-decoration: none;
  transition: background .15s, transform .15s;
}
.btn:hover { background: var(--accent-dark); color: #fff; }
.btn:active { transform: translateY(1px); }
.btn[disabled] { background: #C4CBD7; cursor: not-allowed; }
.btn-small { min-height: 44px; padding: 0 18px; font-size: .92rem; }
.btn-light { background: #fff; color: var(--accent); }
.btn-light:hover { background: var(--accent-tint); color: var(--accent-dark); }
.btn-ghost { background: #fff; color: var(--ink); border: 1.5px solid var(--ink); }
.btn-ghost:hover { background: var(--ink); color: #fff; }
.link-arrow { font-weight: 600; text-decoration: none; display: inline-flex; align-items: center; min-height: 44px; }
.link-arrow::after { content: "→"; margin-left: 8px; transition: transform .15s; }
.link-arrow:hover::after { transform: translateX(3px); }
.linklike { background: none; border: 0; padding: 0; font: inherit; color: var(--ink-soft); cursor: pointer; text-decoration: underline; text-underline-offset: 3px; }

.fine { font-size: .85rem; color: var(--ink-mute); }
.eyebrow { font-size: .85rem; letter-spacing: .04em; text-transform: uppercase; color: var(--accent); font-weight: 600; margin-bottom: 18px; }

/* Hero */
.hero { padding: 72px 0 88px; }
.hero-grid { display: grid; grid-template-columns: 1.1fr .9fr; gap: 64px; align-items: center; }
.lead { font-size: 1.15rem; color: var(--ink-soft); max-width: 36em; margin: 22px 0 30px; }
.cta-row { display: flex; flex-wrap: wrap; align-items: center; gap: 14px 26px; margin-bottom: 14px; }

/* Papier-Karte mit Literaturverzeichnis */
.paper {
  margin: 0; background: #fff; border: 1px solid var(--rule); border-radius: 4px;
  padding: 28px 30px 22px; position: relative;
  box-shadow: 0 1px 0 #fff, 6px 6px 0 -1px #fff, 6px 6px 0 0 var(--rule), 0 18px 40px -24px rgba(27,31,42,.35);
}
.paper-head { display: flex; justify-content: space-between; align-items: baseline; border-bottom: 1px solid var(--rule-strong); padding-bottom: 8px; margin-bottom: 14px; }
.paper-head span:first-child { font-family: var(--serif); font-weight: 600; font-size: 1.15rem; }
.paper-page { font-family: var(--serif); font-size: .85rem; color: var(--ink-mute); }
.refs { list-style: none; margin: 0; padding: 0; font-family: var(--serif); font-size: .92rem; line-height: 1.5; }
.refs li { padding-left: 1.6em; text-indent: -1.6em; margin-bottom: 12px; }
.refs .ref-text { color: var(--ink); }
.refs .chip { text-indent: 0; margin-left: 6px; }
.ref-flag .ref-text { color: var(--ink-mute); font-style: italic; }
.paper figcaption { font-size: .8rem; color: var(--ink-mute); border-top: 1px solid var(--rule); padding-top: 10px; margin-top: 4px; }

.chip { display: inline-block; font: 600 .72rem/1 var(--sans); padding: 4px 7px; border-radius: 4px; white-space: nowrap; vertical-align: 1px; }
.chip.ok { background: var(--accent-tint); color: var(--accent-dark); }
.chip.warn { background: var(--warn-tint); color: var(--warn); }

/* Abschnitte */
.section { padding: 88px 0; }
.section.alt { background: var(--bg-alt); border-top: 1px solid var(--rule); border-bottom: 1px solid var(--rule); }
.sec-head { display: flex; align-items: baseline; gap: 14px; margin-bottom: 18px; }
.sec-num { font-family: var(--serif); font-size: clamp(1.6rem, 3.4vw, 2.3rem); color: var(--accent); font-weight: 600; }
.sec-intro { color: var(--ink-soft); max-width: 42em; margin-bottom: 40px; font-size: 1.05rem; }
sup.fn { font-size: .7em; line-height: 0; margin-left: 2px; }
sup.fn a { text-decoration: none; font-weight: 600; }

.cards { display: grid; gap: 22px; margin-top: 34px; }
.cards.three { grid-template-columns: repeat(3, 1fr); }
.cards.two { grid-template-columns: repeat(2, 1fr); }
.card { background: #fff; border: 1px solid var(--rule); border-radius: var(--radius); padding: 28px; }
.card h3 { margin: 14px 0 8px; }
.card p { color: var(--ink-soft); margin: 0; }
.icon { width: 26px; height: 26px; fill: none; stroke: var(--accent); stroke-width: 1.6; stroke-linecap: round; stroke-linejoin: round; }

/* Zeitleiste */
.timeline { list-style: none; margin: 0; padding: 0; display: grid; grid-template-columns: repeat(2, 1fr); gap: 0 48px; counter-reset: none; }
.timeline li { display: grid; grid-template-columns: 48px 1fr; gap: 16px; padding: 20px 0; border-top: 1px solid var(--rule); }
.t-num { width: 40px; height: 40px; border-radius: 50%; border: 1.5px solid var(--accent); color: var(--accent); font: 600 1.05rem/37px var(--serif); text-align: center; background: #fff; }
.timeline h3 { margin-bottom: 4px; }
.timeline p { margin: 0; color: var(--ink-soft); font-size: .97rem; }

/* Abbildungen */
.figure { margin: 0 0 56px; }
.fig-cap { font-family: var(--serif); font-size: 1rem; color: var(--ink-soft); margin-bottom: 14px; max-width: 48em; }
.fig-cap b { color: var(--ink); }
.fig-note { color: var(--ink-soft); font-size: .95rem; max-width: 46em; margin-top: 18px; }
.table-scroll { overflow-x: auto; -webkit-overflow-scrolling: touch; border-radius: 4px; }

/* Tabellen im booktabs-Stil */
.booktabs { width: 100%; border-collapse: collapse; background: #fff; font-size: .93rem; border-top: 2px solid var(--rule-strong); border-bottom: 2px solid var(--rule-strong); }
.booktabs th, .booktabs td { text-align: left; vertical-align: top; padding: 12px 14px; }
.booktabs thead th { font-family: var(--serif); font-weight: 600; border-bottom: 1px solid var(--rule-strong); font-size: .98rem; }
.booktabs tbody tr + tr th, .booktabs tbody tr + tr td { border-top: 1px solid var(--rule); }
.booktabs tbody th { font-weight: 600; white-space: nowrap; }
.concept { min-width: 760px; }
.concept td { line-height: 1.7; }
.compare { min-width: 600px; }
.compare td:nth-child(2) { color: var(--ink-mute); }
.compare thead th:last-child, .compare td:last-child { background: var(--accent-tint); }
.compare td:last-child { color: var(--ink); }

.pitfall { margin: 18px 0 0; padding: 16px 20px; border-left: 3px solid var(--accent); background: var(--bg-alt); max-width: 52em; }
.pitfall p { margin: 0; font-family: var(--serif); }
.pitfall .pitfall-label { font: 600 .78rem/1.4 var(--sans); text-transform: uppercase; letter-spacing: .05em; color: var(--accent); margin-bottom: 6px; }

/* Suchstring */
.code-wrap { border: 1px solid var(--rule); border-radius: var(--radius); overflow: hidden; background: #fff; }
.code-bar { display: flex; justify-content: space-between; align-items: center; gap: 12px; padding: 8px 10px 8px 16px; background: var(--bg-alt); border-bottom: 1px solid var(--rule); font-size: .85rem; color: var(--ink-soft); }
.copy { font: 600 .85rem var(--sans); color: var(--accent); background: #fff; border: 1px solid var(--rule); border-radius: 6px; padding: 0 12px; min-height: 36px; cursor: pointer; }
.copy:hover { border-color: var(--accent); }
.code { margin: 0; padding: 18px 18px 20px; font: .86rem/1.75 var(--mono); white-space: pre-wrap; word-break: break-word; color: var(--ink); }
.code .op { color: var(--accent); font-weight: 700; }
.code .tag { color: var(--ink-mute); }
.code .str { color: #2A3346; }

.stats { display: grid; grid-template-columns: repeat(3, 1fr); gap: 14px; margin: 18px 0 0; }
.stats div { border-top: 2px solid var(--accent); padding-top: 10px; }
.stats dt { font-size: .8rem; text-transform: uppercase; letter-spacing: .05em; color: var(--ink-mute); }
.stats dd { margin: 4px 0 0; font-family: var(--serif); font-size: 1.15rem; font-weight: 600; }
.stats div:first-child dd { font-size: 1.8rem; color: var(--accent); line-height: 1.2; }

/* Fußnoten */
.notes { margin: 8px 0 0; padding: 14px 0 0 1.4em; border-top: 1px solid var(--rule); font-size: .85rem; color: var(--ink-mute); max-width: 46em; position: relative; }
.notes::before { content: ""; position: absolute; top: -1px; left: 0; width: 120px; border-top: 1px solid var(--ink-mute); }
.notes a { text-decoration: none; }

/* Für wen */
.fit-yes, .fit-no { margin-top: 0 !important; }
.ticks, .crosses { list-style: none; padding: 0; margin: 14px 0 0; }
.ticks li, .crosses li { position: relative; padding-left: 30px; margin-bottom: 10px; color: var(--ink-soft); }
.ticks li::before, .crosses li::before { position: absolute; left: 0; top: 0; font-weight: 700; }
.ticks li::before { content: "✓"; color: var(--accent); }
.crosses li::before { content: "×"; color: var(--ink-mute); font-size: 1.2em; line-height: 1.3; }
.inside { margin-top: 48px; }
.inside h3 { margin-bottom: 18px; }
.inside-list { list-style: none; padding: 0; margin: 0; display: grid; grid-template-columns: repeat(2, 1fr); gap: 16px 40px; }
.inside-list li { display: flex; gap: 14px; align-items: flex-start; color: var(--ink-soft); }
.inside-list .icon { flex: none; margin-top: 2px; }

/* Lead-Formular */
.lead-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 56px; align-items: center; }
.lead-grid p { color: var(--ink-soft); }
.lead-form { background: #fff; border: 1px solid var(--rule); border-radius: var(--radius); padding: 28px; display: grid; gap: 12px; }
.lead-form label { font-weight: 600; font-size: .92rem; }
.lead-form input[type=email] { width: 100%; min-height: 48px; padding: 0 14px; border: 1.5px solid #C4CBD7; border-radius: 8px; font: inherit; color: var(--ink); background: #fff; }
.lead-form input[type=email]:focus { border-color: var(--accent); outline: none; box-shadow: 0 0 0 3px var(--accent-tint); }
.lead-form input:disabled { background: var(--bg-alt); }
.lead-form textarea { width: 100%; padding: 12px 14px; border: 1.5px solid #C4CBD7; border-radius: 8px; font: inherit; color: var(--ink); background: #fff; resize: vertical; }
.lead-form textarea:focus { border-color: var(--accent); outline: none; box-shadow: 0 0 0 3px var(--accent-tint); }
.lead-form input[type=text] { width: 100%; min-height: 48px; padding: 0 14px; border: 1.5px solid #C4CBD7; border-radius: 8px; font: inherit; color: var(--ink); background: #fff; }
.lead-form input[type=text]:focus { border-color: var(--accent); outline: none; box-shadow: 0 0 0 3px var(--accent-tint); }
.contact-form { margin-top: 28px; max-width: 560px; }
.contact-form label:not(.consent) { margin-top: 6px; }
.opt { font-weight: 400; color: var(--ink-mute); }
.hp { position: absolute !important; left: -9999px; width: 1px; height: 1px; opacity: 0; }
.consent { display: flex; gap: 10px; align-items: flex-start; font-weight: 400 !important; font-size: .85rem !important; color: var(--ink-soft); }
.consent input { margin-top: 4px; width: 18px; height: 18px; flex: none; accent-color: var(--accent); }
.lead-form .fine { margin: 0; }

/* FAQ */
.faq details { border-top: 1px solid var(--rule); }
.faq details:last-child { border-bottom: 1px solid var(--rule); }
.faq summary { list-style: none; cursor: pointer; padding: 18px 40px 18px 0; position: relative; font-family: var(--serif); font-weight: 600; font-size: 1.1rem; min-height: 44px; }
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after { content: "+"; position: absolute; right: 6px; top: 14px; font: 400 1.6rem/1 var(--sans); color: var(--accent); transition: transform .2s; }
.faq details[open] summary::after { transform: rotate(45deg); }
.faq details p { color: var(--ink-soft); padding-bottom: 8px; max-width: 44em; }

/* Schluss */
.final { background: var(--accent); color: #fff; padding: 80px 0; text-align: center; }
.final h2 { color: #fff; }
.final p { color: #DCE7FD; margin: 12px 0 28px; font-size: 1.1rem; }

/* Footer */
.site-footer { padding: 32px 0 40px; border-top: 1px solid var(--rule); }
.footer-inner { display: flex; flex-wrap: wrap; justify-content: space-between; align-items: center; gap: 12px 28px; font-size: .9rem; color: var(--ink-soft); }
.footer-inner p { margin: 0; }
.footer-inner nav { display: flex; gap: 20px; flex-wrap: wrap; }
.footer-inner nav a { color: var(--ink-soft); }
.footer-inner .fine { flex-basis: 100%; }

/* Auswahl-Dialog */
.chooser { border: 0; border-radius: 14px; padding: 0; width: min(480px, calc(100vw - 32px)); color: var(--ink); box-shadow: 0 30px 80px -20px rgba(27,31,42,.45); }
.chooser::backdrop { background: rgba(27,31,42,.45); }
.chooser-inner { padding: 32px 28px 28px; position: relative; }
.chooser h2 { font-size: 1.5rem; margin-bottom: 8px; padding-right: 30px; }
.chooser p { color: var(--ink-soft); }
.close { position: absolute; right: 12px; top: 12px; width: 44px; height: 44px; border: 0; background: none; font-size: 1.8rem; line-height: 1; color: var(--ink-mute); cursor: pointer; border-radius: 50%; }
.close:hover { background: var(--bg-alt); color: var(--ink); }
.chooser-options { display: grid; gap: 12px; margin-top: 18px; }
.option { display: flex; justify-content: space-between; align-items: center; gap: 12px; padding: 18px 20px; border: 1.5px solid var(--rule); border-radius: 10px; text-decoration: none; color: var(--ink); }
.option:hover { border-color: var(--accent); background: var(--accent-tint); color: var(--ink); }
.option b { font-family: var(--serif); font-size: 1.1rem; white-space: nowrap; }
.option span { font-size: .9rem; color: var(--ink-soft); }
.option::after { content: "→"; color: var(--accent); font-weight: 700; }

/* Cookie-Banner */
.cookie { position: fixed; left: 16px; right: 16px; bottom: 16px; z-index: 50; max-width: 560px; margin: 0 auto; background: #fff; border: 1px solid var(--rule); border-radius: 12px; padding: 20px 22px; box-shadow: 0 20px 50px -18px rgba(27,31,42,.4); }
.cookie h2 { font-size: 1.1rem; margin-bottom: 6px; }
.cookie p { font-size: .9rem; color: var(--ink-soft); margin-bottom: 14px; }
.cookie-actions { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; }

/* Rechtsseiten */
.legal { padding: 56px 0 80px; }
.legal h1 { font-size: clamp(2rem, 4vw, 2.6rem); margin-bottom: 24px; }
.legal h2 { font-size: 1.35rem; margin: 36px 0 10px; }
.legal p, .legal li { color: var(--ink-soft); max-width: 44em; }
.legal .back { display: inline-block; margin-bottom: 24px; }

/* Einblenden */
.reveal { opacity: 0; transform: translateY(14px); transition: opacity .6s ease, transform .6s ease; }
.reveal.in { opacity: 1; transform: none; }
.no-js .reveal { opacity: 1; transform: none; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; transition: none; }
  * { transition: none !important; }
}

/* Responsiv */
@media (max-width: 940px) {
  .hero-grid { grid-template-columns: 1fr; gap: 48px; }
  .paper { max-width: 560px; }
  .cards.three { grid-template-columns: 1fr; }
  .lead-grid { grid-template-columns: 1fr; gap: 28px; }
}
@media (max-width: 760px) {
  :root { --gutter: 16px; }
  body { font-size: 16px; }
  .nav { display: none; }
  .header-inner { justify-content: space-between; }
  .brand span { font-size: .98rem; }
  .hero { padding: 44px 0 64px; }
  .section { padding: 64px 0; }
  .timeline { grid-template-columns: 1fr; }
  .cards.two, .inside-list { grid-template-columns: 1fr; }
  .stats { grid-template-columns: 1fr; }
  .paper { padding: 22px 20px 18px; }
  .cta-row .btn { width: 100%; }
}
@media (max-width: 400px) {
  .brand span { display: none; }
}