.luk-back {
  --lb-font: "Inter Variable", "Inter", "Noto Sans", system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Arial, sans-serif;
  --lb-bg: linear-gradient(135deg, #1f9a63 0%, #0f7a50 100%);
  --lb-bg-hover: linear-gradient(135deg, #22a86c 0%, #108556 100%);
  --lb-shadow: 0 10px 26px rgba(15, 122, 80, 0.32);
  --lb-shadow-hover: 0 14px 32px rgba(15, 122, 80, 0.40);
  --lb-ring: rgba(31, 154, 99, 0.45);
  --lb-ring-end: rgba(31, 154, 99, 0);
  --lb-focus: #0f6b50;

  display: flex;
  justify-content: center;
  width: 100%;
  margin: 26px auto;
  padding: 0 12px;
  font-family: var(--lb-font);
  text-align: center;
}

.luk-back[hidden] {
  display: none;
}

html.luk-dark .luk-back {
  --lb-shadow: 0 10px 26px rgba(0, 0, 0, 0.35);
  --lb-shadow-hover: 0 14px 32px rgba(0, 0, 0, 0.45);
  --lb-ring: rgba(111, 224, 168, 0.40);
  --lb-ring-end: rgba(111, 224, 168, 0);
  --lb-focus: #a9f0ca;
}

.luk-back,
.luk-back * {
  box-sizing: border-box;
}

/* Button */
.luk-back .luk-back-link,
.luk-back .luk-back-link:visited {
  position: relative;
  overflow: hidden;
  isolation: isolate;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  min-height: 56px;
  padding: 10px 26px 10px 12px;
  border: 0;
  border-radius: 999px;
  background: var(--lb-bg);
  color: #ffffff;
  box-shadow: var(--lb-shadow);
  font-family: inherit;
  font-size: 16px;
  font-weight: 900;
  line-height: 1.2;
  letter-spacing: -0.005em;
  text-decoration: none;
  -webkit-tap-highlight-color: transparent;
  animation: lb-pulse 2.8s ease-out infinite;
  transition: transform 0.2s ease;
}

/* Lichtstreifen */
.luk-back .luk-back-link::before {
  content: "";
  position: absolute;
  top: 0;
  bottom: 0;
  left: -60%;
  z-index: -1;
  width: 45%;
  background: linear-gradient(105deg, transparent 0%, rgba(255, 255, 255, 0.28) 50%, transparent 100%);
  transform: skewX(-18deg);
  animation: lb-shine 4.2s ease-in-out infinite;
  pointer-events: none;
}

/* Pfeil-Kreis */
.luk-back .luk-back-icon {
  display: grid;
  place-items: center;
  flex: 0 0 36px;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.22);
  animation: lb-nudge 2.8s ease-in-out infinite;
}

.luk-back .luk-back-icon svg {
  width: 18px;
  height: 18px;
  fill: none;
  stroke: currentColor;
  stroke-width: 2.4;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.luk-back .luk-back-link:active {
  transform: scale(0.97);
}

.luk-back .luk-back-link:focus-visible {
  outline: 3px solid var(--lb-focus);
  outline-offset: 4px;
}

/* Animationen */
@keyframes lb-pulse {
  0% { box-shadow: var(--lb-shadow), 0 0 0 0 var(--lb-ring); }
  70% { box-shadow: var(--lb-shadow), 0 0 0 14px var(--lb-ring-end); }
  100% { box-shadow: var(--lb-shadow), 0 0 0 0 var(--lb-ring-end); }
}

@keyframes lb-nudge {
  0%, 55%, 100% { transform: translateX(0); }
  65% { transform: translateX(-6px); }
  75% { transform: translateX(0); }
  85% { transform: translateX(-3px); }
}

@keyframes lb-nudge-rtl {
  0%, 55%, 100% { transform: translateX(0); }
  65% { transform: translateX(6px); }
  75% { transform: translateX(0); }
  85% { transform: translateX(3px); }
}

@keyframes lb-shine {
  0% { left: -60%; }
  45%, 100% { left: 130%; }
}

/* Hover nur auf Geräten mit Maus */
@media (hover: hover) {
  .luk-back .luk-back-link:hover {
    background: var(--lb-bg-hover);
    color: #ffffff;
    box-shadow: var(--lb-shadow-hover);
    transform: translateY(-2px);
    text-decoration: none;
    animation: none;
  }

  .luk-back .luk-back-link:hover .luk-back-icon {
    animation: none;
    transform: translateX(-3px);
  }

  html[dir="rtl"] .luk-back .luk-back-link:hover .luk-back-icon {
    transform: translateX(3px);
  }
}

/* Arabische Schriften & RTL */
html:is([lang="ar"], [lang="fa"], [lang="ps"], [lang="ur"]) .luk-back {
  font-family: "Noto Sans Arabic", "Noto Sans", Arial, sans-serif;
}

html:is([lang="ar"], [lang="fa"], [lang="ps"], [lang="ur"]) .luk-back * {
  letter-spacing: 0;
}

html[dir="rtl"] .luk-back {
  direction: rtl;
}

html[dir="rtl"] .luk-back .luk-back-link {
  padding: 10px 12px 10px 26px;
}

html[dir="rtl"] .luk-back .luk-back-icon {
  animation-name: lb-nudge-rtl;
}

html[dir="rtl"] .luk-back .luk-back-icon svg {
  transform: scaleX(-1);
}

/* Weniger Bewegung: alle Effekte aus */
@media (prefers-reduced-motion: reduce) {
  .luk-back .luk-back-link,
  .luk-back .luk-back-link::before,
  .luk-back .luk-back-icon {
    animation: none !important;
    transition: none;
  }

  .luk-back .luk-back-link::before {
    display: none;
  }
}

/* Smartphone: volle Breite */
@media (max-width: 560px) {
  .luk-back .luk-back-link {
    width: 100%;
    max-width: 420px;
  }
}