:root {
  --bp-bg0: #071521;
  --bp-bg1: #0b2236;
  --bp-card: rgba(255, 255, 255, 0.06);
  --bp-card2: rgba(255, 255, 255, 0.085);
  --bp-ink: #f3f7ff;
  --bp-muted: rgba(243, 247, 255, 0.72);
  --bp-dim: rgba(243, 247, 255, 0.55);
  --bp-line: rgba(255, 255, 255, 0.12);
  --bp-brand: #28c7b7;
  --bp-brand2: #ffd166;
  --bp-danger: #ff4d6d;
  --bp-ok: #36d399;

  --bp-radius-lg: 22px;
  --bp-radius-md: 16px;
  --bp-radius-sm: 12px;

  --bp-font-body: "IBM Plex Sans", ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, sans-serif;
  --bp-font-display: "Fraunces", ui-serif, Georgia, serif;

  --bp-font-scale: 1;
}

html, body {
  height: 100%;
}

body {
  font-family: var(--bp-font-body);
  background:
    radial-gradient(1200px 800px at 20% -10%, rgba(40, 199, 183, 0.22), transparent 60%),
    radial-gradient(900px 700px at 110% 10%, rgba(255, 209, 102, 0.18), transparent 55%),
    radial-gradient(900px 700px at 60% 120%, rgba(50, 140, 255, 0.12), transparent 50%),
    linear-gradient(180deg, var(--bp-bg0), var(--bp-bg1));
  color: var(--bp-ink);
  overflow-x: hidden;
}

a {
  color: inherit;
}

.bp-shell {
  min-height: 100%;
  display: flex;
  flex-direction: column;
}

.bp-topbar {
  position: sticky;
  top: 0;
  z-index: 40;
  backdrop-filter: blur(12px);
  background: linear-gradient(180deg, rgba(7, 21, 33, 0.95), rgba(7, 21, 33, 0.65));
  border-bottom: 1px solid var(--bp-line);
}

.bp-brand {
  font-family: var(--bp-font-display);
  letter-spacing: 0.2px;
}

.bp-subtle {
  color: var(--bp-muted);
}

.bp-card {
  background: linear-gradient(180deg, var(--bp-card2), var(--bp-card));
  border: 1px solid var(--bp-line);
  border-radius: var(--bp-radius-lg);
  box-shadow:
    0 20px 60px rgba(0, 0, 0, 0.38),
    0 1px 0 rgba(255, 255, 255, 0.04) inset;
}

.bp-card-sm {
  border-radius: var(--bp-radius-md);
}

.bp-chip {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.35rem 0.6rem;
  border-radius: 999px;
  border: 1px solid var(--bp-line);
  background: rgba(255, 255, 255, 0.04);
  color: var(--bp-muted);
  font-size: 0.9rem;
}

.bp-btn {
  border-radius: 999px;
  border: 1px solid rgba(255, 255, 255, 0.14);
  background: rgba(255, 255, 255, 0.06);
  color: var(--bp-ink);
}

.bp-btn:hover {
  background: rgba(255, 255, 255, 0.09);
}

.bp-btn-primary {
  border: 1px solid rgba(40, 199, 183, 0.45);
  background: linear-gradient(180deg, rgba(40, 199, 183, 0.28), rgba(40, 199, 183, 0.12));
}

.bp-btn-primary:hover {
  background: linear-gradient(180deg, rgba(40, 199, 183, 0.34), rgba(40, 199, 183, 0.16));
}

.bp-btn-ghost {
  border: 1px solid transparent;
  background: transparent;
}

.bp-btn-ghost:hover {
  border-color: var(--bp-line);
  background: rgba(255, 255, 255, 0.04);
}

.bp-input {
  border-radius: 14px;
  border: 1px solid rgba(255, 255, 255, 0.14);
  background: rgba(8, 20, 32, 0.6);
  color: var(--bp-ink);
}

.bp-input:focus {
  box-shadow: 0 0 0 0.25rem rgba(40, 199, 183, 0.18);
  border-color: rgba(40, 199, 183, 0.6);
}

.bp-page {
  flex: 1;
}

.bp-fade-in {
  animation: bp-rise 520ms ease both;
}

@keyframes bp-rise {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: translateY(0); }
}

.bp-bottomnav {
  position: sticky;
  bottom: 0;
  z-index: 30;
  padding-bottom: env(safe-area-inset-bottom);
  backdrop-filter: blur(14px);
  background: linear-gradient(0deg, rgba(7, 21, 33, 0.95), rgba(7, 21, 33, 0.65));
  border-top: 1px solid var(--bp-line);
}

.bp-navbtn {
  appearance: none;
  border: 0;
  background: transparent;
  color: var(--bp-muted);
  padding: 0.65rem 0.5rem;
  border-radius: 14px;
  width: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.3rem;
  font-size: 0.8rem;
}

.bp-navbtn[aria-current="page"] {
  color: var(--bp-ink);
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid rgba(255, 255, 255, 0.12);
}

.bp-kicker {
  text-transform: uppercase;
  letter-spacing: 0.12em;
  font-size: 0.78rem;
  color: var(--bp-dim);
}

.bp-hero-title {
  font-family: var(--bp-font-display);
  font-size: clamp(2.1rem, 6vw, 3.2rem);
  line-height: 1.05;
}

.bp-hero-sub {
  color: var(--bp-muted);
  max-width: 42rem;
}

.bp-divider {
  height: 1px;
  background: var(--bp-line);
  width: 100%;
}

.bp-reading {
  font-size: calc(1rem * var(--bp-font-scale));
  line-height: 1.75;
}

.bp-reading h2, .bp-reading h3 {
  font-family: var(--bp-font-display);
  letter-spacing: 0.2px;
  margin-top: 2rem;
}

.bp-reading img, .bp-reading svg {
  max-width: 100%;
  height: auto;
  border-radius: var(--bp-radius-md);
  border: 1px solid rgba(255, 255, 255, 0.12);
  background: rgba(255, 255, 255, 0.03);
}

.bp-reading .topbild {
  width: 100%;
  height: auto;
}

.bp-focus .bp-topbar,
.bp-focus .bp-bottomnav {
  opacity: 0.2;
  transition: opacity 240ms ease;
}

.bp-focus .bp-topbar:hover,
.bp-focus .bp-bottomnav:hover {
  opacity: 1;
}

.bp-toast {
  position: fixed;
  left: 50%;
  transform: translateX(-50%);
  bottom: calc(72px + env(safe-area-inset-bottom));
  z-index: 100;
  padding: 0.6rem 0.9rem;
  border-radius: 999px;
  border: 1px solid rgba(255, 255, 255, 0.16);
  background: rgba(7, 21, 33, 0.86);
  backdrop-filter: blur(12px);
  color: var(--bp-ink);
  box-shadow: 0 18px 50px rgba(0, 0, 0, 0.42);
}

.bp-hotspot {
  position: absolute;
  width: 22px;
  height: 22px;
  border-radius: 999px;
  background: rgba(255, 209, 102, 0.95);
  box-shadow: 0 0 0 8px rgba(255, 209, 102, 0.18);
  border: 1px solid rgba(0, 0, 0, 0.25);
  cursor: pointer;
}

.bp-hotspot::after {
  content: "";
  position: absolute;
  inset: 6px;
  border-radius: 999px;
  background: rgba(7, 21, 33, 0.8);
}

.bp-interactive-image {
  position: relative;
}

.bp-answer {
  border: 1px solid rgba(255, 255, 255, 0.14);
  background: rgba(255, 255, 255, 0.04);
  border-radius: var(--bp-radius-md);
  padding: 0.85rem 0.9rem;
}

.bp-answer:hover {
  background: rgba(255, 255, 255, 0.065);
}

.bp-answer[aria-checked="true"] {
  border-color: rgba(40, 199, 183, 0.6);
  background: rgba(40, 199, 183, 0.12);
}

.bp-answer.bp-correct {
  border-color: rgba(54, 211, 153, 0.6);
  background: rgba(54, 211, 153, 0.12);
}

.bp-answer.bp-wrong {
  border-color: rgba(255, 77, 109, 0.6);
  background: rgba(255, 77, 109, 0.1);
}