/* ringnull: fonts are self-hosted, nothing is loaded from third parties. */
@font-face { font-family: "Plex Sans"; src: url("fonts/plex-sans-400.woff2") format("woff2"); font-weight: 400; font-display: swap; }
@font-face { font-family: "Plex Sans"; src: url("fonts/plex-sans-500.woff2") format("woff2"); font-weight: 500; font-display: swap; }
@font-face { font-family: "Plex Sans"; src: url("fonts/plex-sans-600.woff2") format("woff2"); font-weight: 600; font-display: swap; }
@font-face { font-family: "Plex Mono"; src: url("fonts/plex-mono-400.woff2") format("woff2"); font-weight: 400; font-display: swap; }

:root {
  --paper: #f3f2ee;
  --paper-deep: #e9e7e0;
  --surface: #fbfaf7;
  --ink: #0b0d12;
  --ink-soft: #454a55;
  --ink-faint: #6b707b;
  --rule: #d6d3ca;
  --accent: #2f6a00;          /* console green, dark enough for text on paper */
  --accent-ink: #ffffff;
  --night: #07090d;
  --night-2: #0d1016;
  --night-ink: #e8e7e2;
  --night-soft: #9da2ad;
  --night-rule: #1d222c;
  --signal: #b6ff6e;          /* the accent on dark backgrounds: prompt, cursor, ring 0 */
  --ok: #1f8a5a;
  --error: #c2361b;
  --sans: "Plex Sans", system-ui, -apple-system, "Segoe UI", sans-serif;
  --mono: "Plex Mono", ui-monospace, Menlo, Consolas, monospace;
  --gutter: clamp(1rem, 4vw, 2.5rem);
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root {
    --paper: #0f1218;
    --paper-deep: #151922;
    --surface: #161a23;
    --ink: #e8e7e2;
    --ink-soft: #b2b6bf;
    --ink-faint: #8a8f99;
    --rule: #2a2f3a;
    --accent: #b6ff6e;
    --accent-ink: #07090d;
    --night: #05070a;
    --night-2: #0d1016;
    --night-rule: #1d222c;
    color-scheme: dark;
  }
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: 5rem;
  -webkit-text-size-adjust: 100%;
}
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font: 400 1.0625rem/1.65 var(--sans);
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, p, ul, ol, dl, dd, figure { margin: 0; }
ul, ol { padding: 0; list-style: none; }

h1, h2 {
  font-weight: 600;
  letter-spacing: -0.035em;
  text-wrap: balance;
}
h1 { font-size: clamp(2.6rem, 6.4vw, 5.25rem); line-height: 0.98; }
h2 { font-size: clamp(1.9rem, 4vw, 3.1rem); line-height: 1.05; }
h3 { font-size: 1.125rem; font-weight: 600; line-height: 1.35; letter-spacing: -0.01em; }

a { color: inherit; text-underline-offset: 0.2em; text-decoration-thickness: 1px; }
a:hover { color: var(--accent); }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; border-radius: 2px; }

.wrap { width: min(72rem, 100% - 2 * var(--gutter)); margin-inline: auto; }

.skip-link {
  position: absolute; left: 1rem; top: -4rem; z-index: 100;
  padding: 0.6rem 1rem; background: var(--accent); color: var(--accent-ink);
}
.skip-link:focus { top: 1rem; }

/* ---------- Labels ---------- */
.eyebrow {
  display: flex; align-items: center; gap: 0.75rem;
  margin-bottom: 1.25rem;
  font: 400 0.8125rem/1 var(--mono);
  letter-spacing: 0.08em; text-transform: uppercase;
  color: var(--ink-faint);
}
.eyebrow--light { color: var(--night-soft); }
/* Console-style section label: "# ring 3 — leistungen" */
.eyebrow { text-transform: none; letter-spacing: 0.02em; font-size: 0.875rem; gap: 0.6rem; }
.ring-no { display: inline-flex; gap: 0.6rem; }
.ring-no::before { content: "#"; color: var(--accent); }
.ring-no::after { content: "—"; }
.eyebrow--light .ring-no::before { color: var(--signal); }

/* Hero prompt line and blinking cursor */
.prompt { margin-bottom: 1.5rem; font: 400 0.9375rem/1.4 var(--mono); color: var(--night-soft); }
.prompt__user { color: var(--signal); }
.cursor { color: var(--signal); font-weight: 400; animation: blink 1.1s steps(1) infinite; }
@keyframes blink { 50% { opacity: 0; } }
@media (prefers-reduced-motion: reduce) { .cursor { animation: none; } }

.lead { max-width: 40rem; margin-top: 1.25rem; font-size: 1.1875rem; color: var(--ink-soft); }

/* ---------- Buttons ---------- */
.button {
  display: inline-flex; align-items: center; justify-content: center;
  min-height: 3rem; padding: 0 1.4rem;
  border: 1px solid var(--ink); border-radius: 0;
  background: var(--ink); color: var(--paper);
  font: 500 0.9375rem/1 var(--sans); text-decoration: none; cursor: pointer;
  transition: background-color 0.15s, color 0.15s, border-color 0.15s;
}
.button:hover { background: var(--accent); border-color: var(--accent); color: var(--accent-ink); }
.button--small { min-height: 2.4rem; padding: 0 1rem; font-size: 0.875rem; }
.button--accent { background: var(--signal); border-color: var(--signal); color: var(--night); }
.button--accent:hover { background: #ffffff; border-color: #ffffff; color: var(--night); }
.button--ghost { background: transparent; border-color: var(--night-rule); color: var(--night-ink); }
.button--ghost:hover { background: transparent; border-color: var(--night-ink); color: #ffffff; }
.button:disabled { opacity: 0.6; cursor: progress; }

/* ---------- Header ---------- */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: color-mix(in srgb, var(--night) 92%, transparent);
  backdrop-filter: blur(10px);
  color: var(--night-ink);
  border-bottom: 1px solid var(--night-rule);
}
.site-header__inner { display: flex; align-items: center; gap: 2rem; min-height: 4rem; }
.brand {
  display: inline-flex; align-items: center; gap: 0.6rem;
  font: 400 1.125rem/1 var(--mono); letter-spacing: -0.02em; text-decoration: none;
}
.brand b { font-weight: 400; color: var(--signal); }
.brand:hover { color: inherit; }
.brand__mark { width: 1.6rem; height: 1.6rem; display: block; }
.site-nav { display: flex; gap: 1.75rem; font-size: 0.9375rem; }
.site-nav a { text-decoration: none; color: var(--night-soft); }
.site-nav a:hover { color: #ffffff; }
.site-header__actions { display: flex; align-items: center; gap: 1rem; margin-left: auto; }
.site-header .button--small { background: var(--night-ink); border-color: var(--night-ink); color: var(--night); }
.site-header .button--small:hover { background: var(--signal); border-color: var(--signal); }

.lang-switch { display: flex; border: 1px solid var(--night-rule); font: 400 0.75rem/1 var(--mono); }
.lang-switch a { padding: 0.5rem 0.6rem; text-decoration: none; color: var(--night-soft); }
.lang-switch a:hover { color: #ffffff; }
.lang-switch a[aria-current] { background: var(--night-ink); color: var(--night); }

.mobile-menu { display: none; position: relative; }
.mobile-menu summary {
  list-style: none; cursor: pointer; padding: 0.5rem 0.75rem;
  border: 1px solid var(--night-rule); font: 400 0.8125rem/1 var(--mono);
}
.mobile-menu summary::-webkit-details-marker { display: none; }
.mobile-menu nav {
  position: absolute; right: 0; top: calc(100% + 0.75rem); min-width: 13rem;
  display: grid; padding: 0.5rem; background: var(--night-2); border: 1px solid var(--night-rule);
}
.mobile-menu nav a { padding: 0.65rem 0.75rem; text-decoration: none; }

/* ---------- Hero ---------- */
.hero {
  position: relative; overflow: hidden;
  background: var(--night); color: var(--night-ink);
  padding: clamp(4rem, 10vw, 7.5rem) 0 0;
}
.hero::before {
  /* a faint measurement grid */
  content: ""; position: absolute; inset: 0; pointer-events: none;
  background-image:
    linear-gradient(var(--night-rule) 1px, transparent 1px),
    linear-gradient(90deg, var(--night-rule) 1px, transparent 1px);
  background-size: 4rem 4rem;
  mask-image: radial-gradient(ellipse at 75% 40%, #000 0%, transparent 70%);
  opacity: 0.55;
}
.hero__grid {
  position: relative;
  display: grid; grid-template-columns: minmax(0, 1.25fr) minmax(0, 1fr);
  gap: clamp(2rem, 6vw, 5rem); align-items: center;
}
.hero h1 { max-width: 12ch; }
.hero__lead { max-width: 34rem; margin-top: 1.75rem; font-size: 1.1875rem; color: var(--night-soft); }
.hero__actions { display: flex; flex-wrap: wrap; gap: 0.75rem; margin-top: 2.25rem; }

.rings { position: relative; width: 100%; max-width: 26rem; justify-self: end; }
.rings svg { display: block; width: 100%; height: auto; overflow: visible; }
.rings__ring { fill: none; stroke: var(--night-soft); stroke-width: 1; opacity: 0.55; }
.rings__orbit {
  fill: none; stroke: var(--signal); stroke-width: 1.5; stroke-dasharray: 2 10;
  transform-origin: 200px 200px; animation: orbit 60s linear infinite;
}
.rings__core { fill: var(--signal); }
.rings__channel { stroke: var(--night); stroke-width: 16; }
.rings__axis { stroke: var(--night-rule); stroke-width: 1; }
.rings text { font: 400 13px var(--mono); fill: var(--night-soft); }
.rings .rings__zero { font-size: 22px; fill: var(--night); }
@keyframes orbit { to { transform: rotate(360deg); } }
@media (prefers-reduced-motion: reduce) { .rings__orbit { animation: none; } }

.facts {
  position: relative;
  display: grid; grid-template-columns: repeat(4, minmax(0, 1fr));
  margin-top: clamp(3.5rem, 8vw, 6rem);
  border-top: 1px solid var(--night-rule);
}
.facts > div { padding: 1.4rem 1.25rem 1.6rem 0; }
.facts > div + div { padding-left: 1.25rem; border-left: 1px solid var(--night-rule); }
.facts dt { font: 400 0.75rem/1 var(--mono); letter-spacing: 0.08em; text-transform: uppercase; color: var(--night-soft); }
.facts dd { margin-top: 0.6rem; font-size: 0.9375rem; line-height: 1.45; }

/* ---------- Sections ---------- */
.section { padding: clamp(4.5rem, 10vw, 8rem) 0; }
.section--tinted { background: var(--paper-deep); }
.section__head { max-width: 46rem; margin-bottom: clamp(2.5rem, 6vw, 4rem); }

/* Services: two columns separated by hairlines, like a spec sheet. */
.services {
  display: grid; grid-template-columns: repeat(2, minmax(0, 1fr));
  border-top: 2px solid var(--ink);
}
.service { padding: 2.25rem 2.5rem 2.75rem 0; }
.service:nth-child(even) { padding-left: 2.5rem; padding-right: 0; border-left: 1px solid var(--rule); }
.service:nth-child(n + 3) { border-top: 1px solid var(--rule); }
.service__label { font: 400 0.8125rem/1 var(--mono); color: var(--accent); }
.service h3 { margin-top: 1rem; font-size: clamp(1.6rem, 2.6vw, 2.1rem); font-weight: 600; letter-spacing: -0.03em; }
.service__summary { margin-top: 1rem; color: var(--ink-soft); font-style: italic; }
.service__body { margin-top: 1rem; }
.service__items { margin-top: 1.75rem; border-top: 1px solid var(--rule); }
.service__items li {
  display: flex; gap: 0.9rem; padding: 0.8rem 0;
  border-bottom: 1px solid var(--rule); font-size: 0.9875rem;
}
.service__items li::before { content: "→"; font-family: var(--mono); color: var(--accent); }

/* Approach: four steps on a line that ends in a filled dot (ring 0). */
.steps {
  display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 2rem;
  counter-reset: step;
}
.step { position: relative; padding-top: 2.25rem; }
.step::before {
  content: ""; position: absolute; top: 0.45rem; left: 0; right: -2rem; height: 1px; background: var(--ink);
}
.step:last-child::before { right: 0; }
.step::after {
  content: ""; position: absolute; top: 0; left: 0; width: 0.95rem; height: 0.95rem;
  border: 1px solid var(--ink); border-radius: 50%; background: var(--paper-deep);
}
.step:last-child::after { background: var(--accent); border-color: var(--accent); }
.step__no { font: 400 0.8125rem/1 var(--mono); color: var(--ink-faint); }
.step h3 { margin-top: 0.6rem; }
.step p { margin-top: 0.6rem; font-size: 0.9875rem; color: var(--ink-soft); }

.approach__foot {
  display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); gap: 2.5rem;
  margin-top: clamp(3rem, 7vw, 5rem); padding-top: 2.5rem; border-top: 1px solid var(--rule);
}
.tags { display: flex; flex-wrap: wrap; gap: 0.5rem; margin-top: 1rem; }
.tags li { padding: 0.45rem 0.8rem; border: 1px solid var(--ink); font-size: 0.9375rem; }
.why { padding: 1.75rem; background: var(--night); color: var(--night-ink); }
.why h3 { font-family: var(--mono); font-weight: 400; color: var(--signal); }
.why p { margin-top: 0.75rem; color: var(--night-soft); }

/* FAQ */
.faq__grid { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1.6fr); gap: clamp(2rem, 6vw, 5rem); }
.faq__grid .section__head { margin-bottom: 0; }
.faq { border-top: 2px solid var(--ink); }
.faq details { border-bottom: 1px solid var(--rule); }
.faq summary {
  display: flex; justify-content: space-between; gap: 1.5rem;
  padding: 1.25rem 0; cursor: pointer; list-style: none; font-weight: 500;
}
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after { content: "+"; font-family: var(--mono); color: var(--accent); }
.faq details[open] summary::after { content: "−"; }
.faq__answer { padding-bottom: 1.5rem; color: var(--ink-soft); }
.faq__answer p + p { margin-top: 0.75rem; }

/* ---------- Contact (ring 0) ---------- */
.contact {
  position: relative; overflow: hidden;
  padding: clamp(4.5rem, 10vw, 8rem) 0;
  background: var(--night); color: var(--night-ink);
}
.contact::before {
  /* the innermost ring, cut by the section edge */
  content: ""; position: absolute; left: -18rem; bottom: -18rem;
  width: 36rem; height: 36rem; border-radius: 50%;
  border: 1px solid var(--night-rule); box-shadow: 0 0 0 6rem var(--night), 0 0 0 calc(6rem + 1px) var(--night-rule);
  pointer-events: none;
}
.contact__grid { position: relative; display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1.1fr); gap: clamp(2.5rem, 6vw, 5rem); }
.contact__lead { margin-top: 1.25rem; max-width: 28rem; color: var(--night-soft); }
.contact__alt { margin-top: 1rem; font-size: 0.9375rem; color: var(--night-soft); }
.contact__alt:first-of-type { margin-top: 2rem; }
.contact a { color: var(--night-ink); }
.contact a:hover { color: var(--signal); }

.form { display: grid; gap: 0.5rem; padding: clamp(1.5rem, 4vw, 2.25rem); background: var(--night-2); border: 1px solid var(--night-rule); }
.form label { margin-top: 0.75rem; font: 400 0.75rem/1 var(--mono); letter-spacing: 0.08em; text-transform: uppercase; color: var(--night-soft); }
.form label:first-child { margin-top: 0; }
.form input, .form textarea {
  width: 100%; padding: 0.85rem 0.9rem;
  background: var(--night); color: var(--night-ink);
  border: 1px solid var(--night-rule); border-radius: 0;
  font: inherit; font-size: 1rem;
}
.form input:focus, .form textarea:focus { outline: none; border-color: var(--signal); }
.form textarea { resize: vertical; min-height: 9rem; }
.form .button { margin-top: 1.25rem; justify-self: start; }
.form__trap { position: absolute; left: -10000px; width: 1px; height: 1px; opacity: 0; }
.form__status { min-height: 1.5rem; font-size: 0.9375rem; color: #7fd6a8; }
.form__status.is-error { color: #ff9b85; }
.form__note { font-size: 0.8125rem; color: var(--night-soft); }

/* ---------- Free pages (imprint, ...) ---------- */
.prose-wrap { max-width: 46rem; }
.page-title { font-size: clamp(2.2rem, 5vw, 3.5rem); margin-bottom: 2.5rem; }
.prose h2 { margin-top: 2.75rem; font-size: 1.5rem; letter-spacing: -0.02em; }
.prose h3 { margin-top: 1.75rem; }
.prose p, .prose ul, .prose ol { margin-top: 0.85rem; color: var(--ink-soft); }
.prose ul { list-style: square; padding-left: 1.25rem; }
.prose ol { list-style: decimal; padding-left: 1.25rem; }
.prose hr { margin: 3rem 0; border: 0; border-top: 1px solid var(--rule); }
.prose code, .not-found code { font-family: var(--mono); font-size: 0.9em; }
.prose a { color: var(--accent); }

.not-found .button { margin-top: 2rem; }
.not-found__url { margin-top: 1rem; color: var(--ink-faint); word-break: break-all; }

/* ---------- Footer ---------- */
.site-footer { padding: 2.5rem 0; background: var(--night); color: var(--night-soft); border-top: 1px solid var(--night-rule); font-size: 0.875rem; }
.site-footer__inner { display: grid; grid-template-columns: 1fr auto; gap: 1rem 2rem; align-items: start; }
.site-footer b { color: var(--night-ink); font-weight: 500; }
.site-footer__sister { margin-top: 0.35rem; }
.site-footer ul { display: flex; flex-wrap: wrap; gap: 0.5rem 1.5rem; }
.site-footer a { color: var(--night-ink); text-decoration: none; }
.site-footer a:hover { color: var(--signal); }
.site-footer__note { grid-column: 1 / -1; font-family: var(--mono); font-size: 0.75rem; }

/* ---------- Responsive ---------- */
@media (max-width: 960px) {
  .site-nav { display: none; }
  .mobile-menu { display: block; }
  .steps { grid-template-columns: repeat(2, minmax(0, 1fr)); row-gap: 2.75rem; }
  .step:nth-child(2n)::before { right: 0; }
  .facts { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .facts > div:nth-child(3) { padding-left: 0; border-left: 0; }
  .facts > div:nth-child(n + 3) { border-top: 1px solid var(--night-rule); }
}

@media (max-width: 760px) {
  .hero__grid, .faq__grid, .contact__grid, .approach__foot, .services { grid-template-columns: 1fr; }
  .rings { max-width: 15rem; justify-self: start; order: -1; }
  .service, .service:nth-child(even) { padding: 2rem 0; border-left: 0; }
  .service + .service { border-top: 1px solid var(--rule); }
  .site-footer__inner { grid-template-columns: 1fr; }
}

@media (max-width: 520px) {
  .site-header__actions .button--small { display: none; }
  .steps { grid-template-columns: 1fr; }
  .step::before { right: 0; }
  .facts { grid-template-columns: 1fr; }
  .facts > div, .facts > div + div { padding-left: 0; border-left: 0; }
  .facts > div + div { border-top: 1px solid var(--night-rule); }
}

/* ---------- Console touches ---------- */
.site-nav { font-family: var(--mono); font-size: 0.875rem; }
.lang-switch { border: 0; gap: 0.1rem; }
.lang-switch a { padding: 0.5rem 0.35rem; }
.lang-switch a[aria-current] { background: none; color: #ffffff; text-decoration: underline; text-underline-offset: 0.3em; }
.lang-switch a + a::before { content: "|"; display: inline-block; margin-right: 0.45rem; color: var(--night-soft); text-decoration: none; }
.site-header .button--console {
  background: transparent; border-color: var(--signal); color: var(--signal);
  font-family: var(--mono); font-weight: 400;
}
.site-header .button--console:hover { background: var(--signal); color: var(--night); }
.facts dt { text-transform: none; letter-spacing: 0.02em; font-size: 0.8125rem; }
.service__keywords { margin-top: 0.85rem; font: 400 0.8125rem/1.6 var(--mono); color: var(--ink-soft); }
.service__label::before { content: "["; }
.service__label::after { content: "]"; }

/* ---------- PGP page ---------- */
.pgp__facts { margin-top: 2.5rem; max-width: 52rem; border-top: 2px solid var(--ink); }
.pgp__facts > div { display: grid; grid-template-columns: 10rem minmax(0, 1fr); gap: 1rem; padding: 0.9rem 0; border-bottom: 1px solid var(--rule); }
.pgp__facts dt { color: var(--ink-faint); font: 400 0.8125rem/1.6 var(--mono); }
.pgp__facts code { font: 400 0.9375rem/1.6 var(--mono); overflow-wrap: anywhere; }
.pgp__fingerprint code { color: var(--accent); font-weight: 600; font-size: 1.0625rem; letter-spacing: 0.02em; }
.pgp__download { margin-top: 2rem; }
.pgp__title { margin-top: clamp(3rem, 6vw, 4.5rem); font-size: clamp(1.6rem, 2.6vw, 2.1rem); }
.pgp__note { max-width: 46rem; margin-top: 1rem; color: var(--ink-soft); }
.console {
  max-width: 52rem; margin: 1.25rem 0 0; overflow-x: auto; padding: 1.1rem 1.25rem;
  background: var(--night); color: var(--night-ink); border: 1px solid var(--night-rule);
  font: 400 0.8125rem/1.7 var(--mono);
}
.console__prompt { color: var(--signal); }
.console--key { max-height: 28rem; white-space: pre; }
@media (max-width: 640px) { .pgp__facts > div { grid-template-columns: minmax(0, 1fr); gap: 0.1rem; } }