/* ============================================================
   optistrom — Marketingsite
   Design-Tokens, Layout, Komponenten
   ============================================================ */

:root {
  --gruen-900: #103d27;
  --gruen-700: #1f7a4d;
  --gruen-600: #2a9461;
  --gruen-500: #3aa86b;
  --gruen-100: #e6f3ec;
  --gruen-050: #f3faf6;

  --gelb-500: #ffc857;
  --gelb-700: #e9a91f;

  --fg:        #14181c;
  --fg-weich: #2a3138;
  --muted:    #5b636b;
  --bg:       #ffffff;
  --bg-alt:   #f6f9f7;
  --bg-dunkel:#0f1c16;
  --rahmen:   #e3e7ea;
  --rahmen-stark: #cdd3d8;

  --schatten-s: 0 1px 2px rgba(16,61,39,0.06), 0 1px 3px rgba(16,61,39,0.04);
  --schatten-m: 0 6px 16px rgba(16,61,39,0.08), 0 2px 6px rgba(16,61,39,0.05);
  --schatten-l: 0 16px 40px rgba(16,61,39,0.12), 0 4px 12px rgba(16,61,39,0.06);

  --radius-s: 6px;
  --radius-m: 12px;
  --radius-l: 20px;

  --wrap: 1180px;
  --wrap-text: 760px;

  --font: "Inter", ui-sans-serif, system-ui, -apple-system, "Segoe UI",
          Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: ui-monospace, "SF Mono", Menlo, Consolas, monospace;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation: none !important; transition: none !important; }
}

body {
  margin: 0;
  font-family: var(--font);
  font-size: 17px;
  line-height: 1.6;
  color: var(--fg);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

img, svg { max-width: 100%; display: block; }

a { color: var(--gruen-700); text-decoration: none; }
a:hover { text-decoration: underline; }

h1, h2, h3, h4 {
  font-weight: 700;
  letter-spacing: -0.01em;
  line-height: 1.2;
  margin: 0 0 0.6em;
  color: var(--fg);
}
h1 { font-size: clamp(2.1rem, 4.2vw + 0.5rem, 3.4rem); letter-spacing: -0.02em; }
h2 { font-size: clamp(1.6rem, 2.5vw + 0.6rem, 2.3rem); }
h3 { font-size: 1.15rem; }
h4 { font-size: 0.95rem; text-transform: uppercase; letter-spacing: 0.06em; color: var(--muted); }

p { margin: 0 0 1em; }

.wrap {
  width: 100%;
  max-width: var(--wrap);
  margin: 0 auto;
  padding: 0 1.25rem;
}

.zentriert { text-align: center; }
.maxbreite { max-width: var(--wrap-text); margin-left: auto; margin-right: auto; }
.maxbreite-text { max-width: var(--wrap-text); margin-left: auto; margin-right: auto; }

.eyebrow {
  display: inline-block;
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--gruen-700);
  background: var(--gruen-100);
  padding: 0.3rem 0.7rem;
  border-radius: 999px;
  margin: 0 0 1.2rem;
}
.eyebrow.zentriert { display: block; width: max-content; margin-left: auto; margin-right: auto; }

.lead {
  font-size: 1.1rem;
  color: var(--fg-weich);
  line-height: 1.65;
}

.akzent { color: var(--gruen-700); }

/* Skip-Link für Tastatur */
.skip {
  position: absolute;
  top: -40px; left: 1rem;
  background: var(--gruen-700);
  color: #fff;
  padding: 0.5rem 0.9rem;
  border-radius: var(--radius-s);
  z-index: 1000;
}
.skip:focus { top: 0.75rem; }

/* ===== Header ===== */
.kopf {
  position: sticky; top: 0; z-index: 50;
  background: rgba(255,255,255,0.85);
  backdrop-filter: saturate(140%) blur(10px);
  -webkit-backdrop-filter: saturate(140%) blur(10px);
  border-bottom: 1px solid var(--rahmen);
}
.kopf-inhalt {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
  height: 64px;
}
.marke {
  display: inline-flex;
  align-items: center;
  gap: 0.55rem;
  font-weight: 700;
  font-size: 1.15rem;
  color: var(--fg);
  letter-spacing: -0.01em;
}
.marke:hover { text-decoration: none; color: var(--gruen-700); }
.logo { width: 30px; height: 30px; }

.nav-haupt {
  display: flex;
  align-items: center;
  gap: 1.6rem;
}
.nav-haupt a {
  color: var(--fg-weich);
  font-weight: 500;
  font-size: 0.95rem;
}
.nav-haupt a:hover { color: var(--gruen-700); text-decoration: none; }
.nav-haupt .btn { font-size: 0.9rem; }

.burger {
  display: none;
  width: 42px; height: 42px;
  border: 1px solid var(--rahmen);
  background: #fff;
  border-radius: var(--radius-s);
  cursor: pointer;
  padding: 0;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 4px;
}
.burger span {
  width: 18px; height: 2px;
  background: var(--fg);
  border-radius: 2px;
  transition: transform .2s, opacity .2s;
}
.burger[aria-expanded="true"] span:nth-child(1) { transform: translateY(6px) rotate(45deg); }
.burger[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.burger[aria-expanded="true"] span:nth-child(3) { transform: translateY(-6px) rotate(-45deg); }

.nav-mobil {
  display: flex;
  flex-direction: column;
  padding: 0.5rem 1.25rem 1.25rem;
  gap: 0.25rem;
  border-bottom: 1px solid var(--rahmen);
  background: #fff;
}
.nav-mobil a {
  padding: 0.7rem 0.4rem;
  border-bottom: 1px solid var(--rahmen);
  color: var(--fg);
  font-weight: 500;
}
.nav-mobil a:last-child { border: none; margin-top: 0.5rem; }
.nav-mobil .btn { text-align: center; }

/* ===== Buttons ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.45rem;
  padding: 0.75rem 1.25rem;
  border-radius: var(--radius-s);
  font-weight: 600;
  font-size: 1rem;
  line-height: 1;
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform .15s, box-shadow .15s, background .15s, color .15s, border-color .15s;
  white-space: nowrap;
}
.btn:hover { text-decoration: none; transform: translateY(-1px); }
.btn:active { transform: translateY(0); }

.btn-primaer {
  background: var(--gruen-700);
  color: #fff;
  box-shadow: var(--schatten-s);
}
.btn-primaer:hover {
  background: var(--gruen-600);
  box-shadow: var(--schatten-m);
  color: #fff;
}

.btn-sekundaer {
  background: #fff;
  color: var(--fg);
  border-color: var(--rahmen-stark);
}
.btn-sekundaer:hover {
  border-color: var(--gruen-700);
  color: var(--gruen-700);
}

.btn-klein { padding: 0.5rem 0.9rem; font-size: 0.9rem; }
.btn-gross { padding: 0.95rem 1.5rem; font-size: 1.05rem; }

.cta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin: 1.6rem 0 1.4rem;
}

/* ===== Hero ===== */
.hero {
  padding: 4rem 0 4.5rem;
  background:
    radial-gradient(60% 70% at 85% 10%, var(--gruen-100) 0%, transparent 60%),
    radial-gradient(45% 55% at 5% 35%, #fff5d8 0%, transparent 70%),
    linear-gradient(180deg, #ffffff 0%, var(--gruen-050) 100%);
}
.hero-grid {
  display: grid;
  grid-template-columns: 1.05fr 1fr;
  gap: 3.5rem;
  align-items: center;
}
.hero h1 { margin-bottom: 1rem; }
.hero-stats {
  display: flex;
  gap: 2rem;
  padding: 0;
  margin: 1.6rem 0 0;
  list-style: none;
  border-top: 1px solid var(--rahmen);
  padding-top: 1.2rem;
}
.hero-stats li {
  display: flex;
  flex-direction: column;
}
.hero-stats strong {
  font-size: 1.5rem;
  color: var(--gruen-700);
  font-weight: 700;
  letter-spacing: -0.02em;
}
.hero-stats span {
  font-size: 0.85rem;
  color: var(--muted);
}

.hero-visual {
  background: #fff;
  border: 1px solid var(--rahmen);
  border-radius: var(--radius-l);
  padding: 1.4rem 1.4rem 1.1rem;
  box-shadow: var(--schatten-l);
}
.hero-chart {
  width: 100%;
  height: auto;
  border-radius: var(--radius-m);
  background: linear-gradient(180deg, #fafbfa 0%, #ffffff 100%);
}
.hero-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  margin-top: 0.9rem;
}
.tag {
  display: inline-block;
  font-size: 0.78rem;
  font-weight: 500;
  padding: 0.25rem 0.6rem;
  background: var(--gruen-050);
  color: var(--gruen-700);
  border: 1px solid var(--gruen-100);
  border-radius: 999px;
}

/* ===== Abschnitte ===== */
.abschnitt {
  padding: 5rem 0;
}
.abschnitt-alt {
  background: var(--bg-alt);
  border-top: 1px solid var(--rahmen);
  border-bottom: 1px solid var(--rahmen);
}

/* ===== Warum ===== */
.warum-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
  margin-top: 3rem;
}
.warum-karte {
  position: relative;
  background: #fff;
  border: 1px solid var(--rahmen);
  border-radius: var(--radius-m);
  padding: 1.8rem 1.5rem 1.5rem;
  transition: transform .2s, box-shadow .2s, border-color .2s;
}
.warum-karte:hover {
  transform: translateY(-3px);
  box-shadow: var(--schatten-m);
  border-color: var(--gruen-100);
}
.warum-zahl {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 38px; height: 38px;
  border-radius: 50%;
  background: var(--gruen-100);
  color: var(--gruen-700);
  font-weight: 700;
  font-size: 1.05rem;
  margin-bottom: 0.9rem;
}
.warum-karte h3 { margin-bottom: 0.4rem; }
.warum-karte p { color: var(--muted); margin: 0; }

/* ===== Features ===== */
.features-grid {
  margin-top: 3rem;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.25rem;
}
.feature {
  background: #fff;
  border: 1px solid var(--rahmen);
  border-radius: var(--radius-m);
  padding: 1.5rem 1.4rem 1.4rem;
  transition: transform .2s, box-shadow .2s, border-color .2s;
}
.feature:hover {
  transform: translateY(-3px);
  box-shadow: var(--schatten-m);
  border-color: var(--gruen-100);
}
.feature .icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 44px; height: 44px;
  border-radius: 10px;
  background: var(--gruen-100);
  color: var(--gruen-700);
  margin-bottom: 0.9rem;
}
.feature .icon svg { width: 24px; height: 24px; }
.feature h3 { margin-bottom: 0.3rem; }
.feature p { color: var(--muted); margin: 0; font-size: 0.97rem; }

/* ===== Ablauf ===== */
.ablauf {
  margin: 3rem 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1.25rem;
  counter-reset: ablauf;
}
.ablauf li {
  position: relative;
  background: #fff;
  border: 1px solid var(--rahmen);
  border-radius: var(--radius-m);
  padding: 1.6rem 1.4rem 1.4rem;
}
.ablauf li::after {
  content: "";
  position: absolute;
  top: 36px; right: -14px;
  width: 14px; height: 2px;
  background: var(--rahmen-stark);
}
.ablauf li:last-child::after { display: none; }

.schritt-nr {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--gruen-700);
  background: var(--gruen-100);
  padding: 0.2rem 0.5rem;
  border-radius: var(--radius-s);
  margin-bottom: 0.8rem;
  letter-spacing: 0.04em;
}
.ablauf h3 { margin-bottom: 0.35rem; }
.ablauf p { color: var(--muted); margin: 0; font-size: 0.95rem; }

/* ===== Tabs ===== */
.tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  justify-content: center;
  margin: 2.5rem 0 1.8rem;
  padding: 0.4rem;
  background: #fff;
  border: 1px solid var(--rahmen);
  border-radius: 999px;
  width: max-content;
  max-width: 100%;
  margin-left: auto;
  margin-right: auto;
}
.tab {
  appearance: none;
  background: transparent;
  border: none;
  font-family: inherit;
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--fg-weich);
  padding: 0.5rem 1.1rem;
  border-radius: 999px;
  cursor: pointer;
  transition: background .15s, color .15s;
}
.tab:hover { color: var(--gruen-700); }
.tab.aktiv {
  background: var(--gruen-700);
  color: #fff;
}

.tab-panel { animation: fadein .25s ease-out; }
@keyframes fadein { from { opacity: 0; transform: translateY(4px); } to { opacity: 1; transform: none; } }

.einsatz {
  display: grid;
  grid-template-columns: 1.4fr 1fr;
  gap: 2rem;
  align-items: center;
  background: #fff;
  border: 1px solid var(--rahmen);
  border-radius: var(--radius-m);
  padding: 2rem;
}
.einsatz h3 { margin-bottom: 0.8rem; }
.einsatz-zitat {
  background: var(--gruen-050);
  border-left: 4px solid var(--gruen-700);
  border-radius: var(--radius-s);
  padding: 1.2rem 1.4rem;
  color: var(--gruen-900);
  font-style: italic;
  font-size: 1.05rem;
}
.einsatz-zitat p { margin: 0; }

.check-liste {
  margin: 0.5rem 0 0;
  padding: 0;
  list-style: none;
}
.check-liste li {
  position: relative;
  padding: 0.3rem 0 0.3rem 1.7rem;
  color: var(--fg-weich);
}
.check-liste li::before {
  content: "";
  position: absolute;
  left: 0; top: 0.55rem;
  width: 18px; height: 18px;
  background: var(--gruen-100) url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24'><path fill='%231f7a4d' d='M9 16.2 4.8 12l-1.4 1.4L9 19l12-12-1.4-1.4z'/></svg>") center/12px no-repeat;
  border-radius: 50%;
}

/* ===== Tech ===== */
.tech-grid {
  display: grid;
  grid-template-columns: 1.1fr 1fr;
  gap: 3rem;
  align-items: center;
}
.tech-karten {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1rem;
}
.tech-karte {
  background: linear-gradient(135deg, var(--gruen-700), var(--gruen-500));
  color: #fff;
  border-radius: var(--radius-m);
  padding: 1.4rem 1.3rem;
  box-shadow: var(--schatten-m);
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
}
.tech-karte strong {
  font-size: 1.8rem;
  letter-spacing: -0.02em;
  font-weight: 700;
}
.tech-karte span {
  font-size: 0.9rem;
  opacity: 0.92;
}
.tech-karte:nth-child(2) { background: linear-gradient(135deg, #205d3f, #1f7a4d); }
.tech-karte:nth-child(3) { background: linear-gradient(135deg, var(--gelb-700), var(--gelb-500)); color: #2d2406; }
.tech-karte:nth-child(4) { background: linear-gradient(135deg, #103d27, #205d3f); }

/* ===== FAQ ===== */
#faq details {
  background: #fff;
  border: 1px solid var(--rahmen);
  border-radius: var(--radius-m);
  padding: 1rem 1.25rem;
  margin-bottom: 0.8rem;
  transition: border-color .15s, box-shadow .15s;
}
#faq details[open] {
  border-color: var(--gruen-100);
  box-shadow: var(--schatten-s);
}
#faq summary {
  font-weight: 600;
  cursor: pointer;
  list-style: none;
  padding-right: 2rem;
  position: relative;
  color: var(--fg);
}
#faq summary::-webkit-details-marker { display: none; }
#faq summary::after {
  content: "+";
  position: absolute;
  right: 0; top: 50%;
  transform: translateY(-50%);
  font-size: 1.4rem;
  font-weight: 400;
  color: var(--gruen-700);
  transition: transform .2s;
}
#faq details[open] summary::after { content: "−"; }
#faq details p {
  margin: 0.8rem 0 0;
  color: var(--fg-weich);
}

/* ===== Kontakt ===== */
.kontakt {
  background:
    radial-gradient(50% 80% at 80% 50%, rgba(58,168,107,0.18) 0%, transparent 60%),
    linear-gradient(135deg, var(--gruen-900) 0%, #143a26 60%, #1c5638 100%);
  color: #f5fbf7;
}
.kontakt h2 { color: #ffffff; }
.kontakt .lead { color: #cfe2d5; }
.kontakt .eyebrow {
  background: rgba(255,255,255,0.12);
  color: #c8f0d6;
}
.kontakt-box {
  display: grid;
  grid-template-columns: 1.4fr 1fr;
  gap: 3rem;
  align-items: center;
}
.kontakt-aktion {
  display: flex;
  flex-direction: column;
  gap: 0.8rem;
}
.kontakt-aktion .btn-primaer {
  background: var(--gelb-500);
  color: #1a1402;
}
.kontakt-aktion .btn-primaer:hover {
  background: #ffd97a;
  color: #1a1402;
}
.kontakt-aktion .btn-sekundaer {
  background: transparent;
  border-color: rgba(255,255,255,0.4);
  color: #fff;
}
.kontakt-aktion .btn-sekundaer:hover {
  background: rgba(255,255,255,0.08);
  border-color: #fff;
  color: #fff;
}

/* ===== Footer ===== */
.fuss {
  background: #0d1612;
  color: #b8c2bd;
  padding: 3.5rem 0 1.5rem;
}
.fuss h4 {
  color: #fff;
  margin-bottom: 0.8rem;
}
.fuss a { color: #c9d1cc; }
.fuss a:hover { color: #fff; }
.fuss-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr;
  gap: 2.5rem;
}
.fuss ul {
  list-style: none;
  padding: 0;
  margin: 0;
}
.fuss ul li {
  padding: 0.25rem 0;
}
.marke-fuss { color: #fff; }
.marke-fuss:hover { color: #fff; }
.fuss-claim {
  margin: 0.8rem 0 0;
  color: #95a09a;
  max-width: 28rem;
  font-size: 0.95rem;
}
.fuss-unten {
  max-width: var(--wrap);
  margin: 2.5rem auto 0;
  padding: 1.2rem 1.25rem 0;
  border-top: 1px solid rgba(255,255,255,0.08);
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.5rem;
  font-size: 0.85rem;
  color: #8a948f;
}

/* ===== Responsive ===== */
@media (max-width: 980px) {
  .hero-grid { grid-template-columns: 1fr; gap: 2rem; }
  .warum-grid { grid-template-columns: 1fr 1fr; }
  .features-grid { grid-template-columns: 1fr 1fr; }
  .ablauf { grid-template-columns: 1fr 1fr; }
  .ablauf li::after { display: none; }
  .einsatz { grid-template-columns: 1fr; padding: 1.5rem; }
  .tech-grid { grid-template-columns: 1fr; gap: 2rem; }
  .kontakt-box { grid-template-columns: 1fr; gap: 1.5rem; }
  .fuss-grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 720px) {
  body { font-size: 16px; }
  .abschnitt { padding: 3.5rem 0; }
  .hero { padding: 2.5rem 0 3rem; }
  .nav-haupt { display: none; }
  .burger { display: inline-flex; }
  .warum-grid { grid-template-columns: 1fr; }
  .features-grid { grid-template-columns: 1fr; }
  .ablauf { grid-template-columns: 1fr; }
  .tech-karten { grid-template-columns: 1fr 1fr; }
  .fuss-grid { grid-template-columns: 1fr; gap: 1.8rem; }
  .hero-stats { gap: 1.2rem; }
  .hero-stats strong { font-size: 1.25rem; }
  .kontakt-aktion .btn { width: 100%; }
}

@media (max-width: 420px) {
  .tabs { width: 100%; justify-content: stretch; }
  .tab { flex: 1; padding: 0.55rem 0.6rem; font-size: 0.88rem; }
  .tech-karten { grid-template-columns: 1fr; }
}