:root {
  color-scheme: dark;
  --bg: radial-gradient(circle at top, #0b1626 0%, #02060c 50%, #000000 100%);
  --card-bg: rgba(10, 18, 30, 0.92);
  --card-border: rgba(85, 150, 255, 0.35);
  --surface: rgba(14, 28, 46, 0.65);
  --accent: #3ce882;
  --accent-strong: #17b55c;
  --text: #f0f4ff;
  --text-muted: #8ea1c7;
  --danger: #ff7b7b;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: "Space Grotesk", "Segoe UI", sans-serif;
  background: var(--bg);
  display: flex;
  justify-content: center;
  align-items: center;
  color: var(--text);
}

.page-shell {
  width: 100%;
  padding: 2.5rem 1.5rem;
  display: flex;
  justify-content: center;
}

.security-card {
  width: min(560px, 100%);
  display: flex;
  flex-direction: column;
  gap: 2rem;
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 20px;
  padding: clamp(1.75rem, 3vw, 2.75rem);
  box-shadow: 0 32px 70px rgba(8, 16, 26, 0.6);
  backdrop-filter: blur(22px);
}

.card-head {
  display: flex;
  gap: 1.25rem;
  align-items: center;
}

.badge {
  flex: 0 0 72px;
  height: 72px;
  display: grid;
  place-items: center;
  border-radius: 18px;
  background: linear-gradient(135deg, rgba(60, 232, 130, 0.25), rgba(17, 33, 53, 0.55));
  box-shadow: inset 0 0 0 1px rgba(60, 232, 130, 0.25);
}

.badge svg {
  width: 48px;
  height: 48px;
}

h1 {
  font-size: clamp(1.55rem, 1.8vw + 1rem, 2.05rem);
  margin: 0;
  letter-spacing: 0.02em;
}

.card-head p {
  margin: 0.35rem 0 0;
  color: var(--text-muted);
  font-size: 1rem;
}

.destination {
  background: var(--surface);
  border: 1px solid rgba(85, 150, 255, 0.25);
  border-radius: 14px;
  padding: 1rem 1.25rem;
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
}

.destination .muted {
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.18em;
  color: rgba(142, 161, 199, 0.7);
}

.destination-host {
  font-weight: 600;
  font-size: 1.05rem;
  color: var(--accent);
}

.destination-url {
  font-family: "JetBrains Mono", "Fira Code", monospace;
  font-size: 0.85rem;
  word-break: break-all;
  color: var(--text-muted);
}

.challenge-area {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.challenge-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
}

.challenge-title {
  text-transform: uppercase;
  letter-spacing: 0.18em;
  font-size: 0.82rem;
  color: rgba(142, 161, 199, 0.8);
}

.challenge-refresh {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  background: rgba(12, 24, 42, 0.65);
  border: 1px solid rgba(142, 161, 199, 0.25);
  color: var(--text);
  border-radius: 10px;
  padding: 0.45rem 0.9rem;
  font-size: 0.85rem;
  font-weight: 500;
  cursor: pointer;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.challenge-refresh svg {
  width: 18px;
  height: 18px;
}

.challenge-refresh:hover,
.challenge-refresh:focus-visible {
  transform: translateY(-1px);
  box-shadow: 0 12px 30px rgba(12, 24, 42, 0.45);
}

.challenge-visual {
  position: relative;
  border-radius: 16px;
  overflow: hidden;
  background: linear-gradient(135deg, rgba(60, 232, 130, 0.12), rgba(23, 181, 92, 0.08));
  border: 1px solid rgba(60, 232, 130, 0.3);
  padding: 1.85rem 1.5rem 1.4rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}

.challenge-wave {
  position: absolute;
  inset: 0;
  background: radial-gradient(circle at 20% 20%, rgba(60, 232, 130, 0.28), transparent 55%),
    radial-gradient(circle at 80% 30%, rgba(16, 38, 58, 0.45), transparent 60%),
    radial-gradient(circle at 50% 80%, rgba(17, 181, 92, 0.2), transparent 65%);
  opacity: 0.75;
}

.challenge-code {
  position: relative;
  font-family: "Space Grotesk", "JetBrains Mono", monospace;
  font-size: clamp(2.25rem, 4vw, 3rem);
  font-weight: 700;
  letter-spacing: 0.35em;
  text-transform: uppercase;
  color: var(--text);
  text-shadow: 0 8px 28px rgba(10, 18, 30, 0.65);
  z-index: 1;
}

.challenge-inputs {
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
}

#challenge-input {
  flex: 1 1 220px;
  background: rgba(6, 12, 24, 0.88);
  border: 1px solid rgba(62, 103, 170, 0.5);
  border-radius: 10px;
  padding: 0.85rem 1.1rem;
  color: var(--text);
  font-size: 1rem;
  letter-spacing: 0.08em;
}

#challenge-input:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(60, 232, 130, 0.2);
}

.btn-confirm {
  background: rgba(17, 33, 53, 0.9);
  color: var(--text);
  border: 1px solid rgba(142, 161, 199, 0.35);
  padding: 0.75rem 1.6rem;
  border-radius: 10px;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  cursor: pointer;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.btn-confirm:hover,
.btn-confirm:focus-visible {
  transform: translateY(-1px);
  box-shadow: 0 14px 35px rgba(17, 33, 53, 0.45);
}

.challenge-feedback {
  margin: 0;
  font-size: 0.92rem;
  color: var(--text-muted);
}

.challenge-feedback.error {
  color: var(--danger);
}

.challenge-feedback.success {
  color: var(--accent);
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  border: 0;
}

.actions {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  justify-content: flex-end;
}

.btn {
  border: 0;
  border-radius: 12px;
  padding: 0.8rem 1.6rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  cursor: pointer;
  transition: transform 0.2s ease, box-shadow 0.2s ease, opacity 0.2s ease;
}

.btn:disabled {
  opacity: 0.6;
  cursor: not-allowed;
  box-shadow: none;
  transform: none;
}

.btn-primary {
  background: linear-gradient(135deg, var(--accent) 0%, var(--accent-strong) 100%);
  color: #02140c;
  box-shadow: 0 18px 40px rgba(60, 232, 130, 0.35);
}

.btn-primary:not(:disabled):hover,
.btn-primary:not(:disabled):focus-visible {
  transform: translateY(-2px);
  box-shadow: 0 24px 55px rgba(60, 232, 130, 0.45);
}

.btn-secondary {
  background: rgba(12, 24, 42, 0.8);
  color: var(--text);
  border: 1px solid rgba(142, 161, 199, 0.3);
}

.btn-secondary:not(:disabled):hover,
.btn-secondary:not(:disabled):focus-visible {
  transform: translateY(-2px);
  box-shadow: 0 18px 40px rgba(12, 24, 42, 0.5);
}

.disclaimer {
  margin: 0;
  color: rgba(142, 161, 199, 0.75);
  font-size: 0.85rem;
  line-height: 1.6;
}

.error-card {
  width: min(480px, 100%);
  background: var(--card-bg);
  border: 1px solid rgba(245, 122, 122, 0.4);
  border-radius: 20px;
  padding: 2.5rem;
  text-align: center;
  box-shadow: 0 32px 70px rgba(30, 0, 0, 0.45);
}

.error-card h2 {
  margin-top: 0;
  color: var(--danger);
  letter-spacing: 0.04em;
}

@media (max-width: 640px) {
  .security-card {
    padding: 1.75rem;
    gap: 1.6rem;
  }

  .card-head {
    align-items: flex-start;
  }

  .badge {
    flex-basis: 60px;
    height: 60px;
  }

  .actions {
    justify-content: stretch;
  }

  .btn {
    flex: 1 1 45%;
  }
}