:root {
  --bg-start: #060c1a;
  --bg-end: #0b1222;
  --accent-1: #38bdf8;
  --accent-2: #22d3ee;
  --accent-3: #7dd3fc;
  --border-soft: rgba(124, 152, 194, 0.26);
  --border-strong: rgba(56, 189, 248, 0.42);
  --text-main: #e7eefb;
  --text-muted: #a4b4cf;
  --font-ui: ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Arial, sans-serif;
}

* {
  box-sizing: border-box;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

html {
  min-height: 100%;
  background-color: var(--bg-start);
  background:
    radial-gradient(900px 500px at 15% 12%, rgba(56, 189, 248, 0.2), transparent 60%),
    radial-gradient(800px 520px at 85% 8%, rgba(34, 211, 238, 0.14), transparent 60%),
    radial-gradient(900px 600px at 50% 100%, rgba(56, 189, 248, 0.12), transparent 55%),
    linear-gradient(180deg, var(--bg-start), var(--bg-end));
}

body {
  margin: 0;
  min-height: 100vh;
  min-height: 100dvh;
  display: grid;
  place-items: center;
  padding: calc(24px + env(safe-area-inset-top)) 24px calc(24px + env(safe-area-inset-bottom));
  color: var(--text-main);
  font-family: var(--font-ui);
  background-color: var(--bg-start);
  background:
    radial-gradient(900px 500px at 15% 12%, rgba(56, 189, 248, 0.2), transparent 60%),
    radial-gradient(800px 520px at 85% 8%, rgba(34, 211, 238, 0.14), transparent 60%),
    radial-gradient(900px 600px at 50% 100%, rgba(56, 189, 248, 0.12), transparent 55%),
    linear-gradient(180deg, var(--bg-start), var(--bg-end));
}

.app {
  width: min(760px, 100%);
  text-align: center;
  border: 1px solid var(--border-soft);
  border-radius: 18px;
  padding: 22px 18px 18px;
  background:
    linear-gradient(145deg, rgba(15, 25, 46, 0.58), rgba(8, 13, 25, 0.9)),
    rgba(10, 17, 34, 0.78);
  box-shadow:
    inset 0 1px 0 rgba(255, 255, 255, 0.05),
    0 20px 60px rgba(2, 8, 23, 0.55),
    0 0 40px rgba(56, 189, 248, 0.12);
  position: relative;
  overflow: hidden;
}

.app::before {
  content: "";
  position: absolute;
  inset: -2px -2px auto -2px;
  height: 4px;
  background: linear-gradient(90deg, var(--accent-1), var(--accent-2), var(--accent-3), var(--accent-2), var(--accent-1));
  opacity: 0.95;
}

.title {
  margin: 0 0 8px;
  font-size: clamp(26px, 4vw, 36px);
  letter-spacing: 0;
  font-family: var(--font-ui);
}

.stats {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 6px 12px;
  margin: 0 auto 10px;
  border: 1px solid var(--border-soft);
  border-radius: 999px;
  background: rgba(7, 12, 26, 0.7);
  color: var(--text-muted);
  font-size: 13px;
}

.stats b {
  color: var(--accent-1);
}

.text {
  margin: 6px 0;
  color: var(--text-muted);
}

.board {
  margin-top: 14px;
}

.card {
  min-height: 90px;
  display: grid;
  align-items: center;
  padding: 14px;
  border: 1px solid var(--border-soft);
  border-radius: 14px;
  background:
    linear-gradient(160deg, rgba(18, 29, 54, 0.55), rgba(9, 16, 31, 0.82)),
    rgba(10, 18, 35, 0.66);
}

.riddle {
  margin: 0;
  text-align: center;
  font-size: clamp(1.1rem, 2.4vw, 1.5rem);
  font-weight: 700;
  line-height: 1.4;
}

.panel {
  margin-top: 14px;
  padding: 12px;
  border: 1px solid var(--border-soft);
  border-radius: 14px;
  background: rgba(0, 0, 0, 0.2);
  display: grid;
  gap: 8px;
}

.controls {
  display: grid;
  grid-template-columns: 1fr 140px;
  gap: 10px;
}

#answerInput {
  border: 1px solid rgba(124, 152, 194, 0.35);
  background: rgba(6, 11, 24, 0.82);
  color: var(--text-main);
  border-radius: 12px;
  padding: 12px 14px;
  font-size: 1rem;
  outline: none;
  transition: border-color 160ms ease, box-shadow 160ms ease;
  font-family: inherit;
}

#answerInput::placeholder {
  color: rgba(164, 180, 207, 0.8);
}

#answerInput:focus {
  border-color: var(--accent-1);
  box-shadow: 0 0 0 4px rgba(56, 189, 248, 0.18);
}

#checkButton {
  border: 1px solid var(--border-strong);
  border-radius: 12px;
  background:
    linear-gradient(135deg, rgba(56, 189, 248, 0.35), rgba(34, 211, 238, 0.22)),
    rgba(12, 26, 49, 0.85);
  color: var(--text-main);
  cursor: pointer;
  font-weight: 700;
  transition: transform 0.08s ease, border-color 0.15s ease, box-shadow 0.15s ease;
  font-family: inherit;
}

#checkButton:hover {
  border-color: rgba(125, 211, 252, 0.85);
  box-shadow: 0 10px 24px rgba(14, 116, 144, 0.3);
  transform: translateY(-1px);
}

#checkButton:active {
  transform: translateY(0);
}

#checkButton:disabled,
#answerInput:disabled {
  opacity: 0.58;
  cursor: not-allowed;
}

.msg {
  margin: 0;
  color: #d7e6fb;
  font-weight: 600;
  min-height: 24px;
}

.hint {
  margin: 0;
  color: var(--accent-3);
  font-size: 13px;
  min-height: 20px;
}

.footer {
  margin-top: 16px;
  padding-top: 14px;
  border-top: 1px solid var(--border-soft);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  position: relative;
}

.footer::before {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  top: -1px;
  height: 1px;
  opacity: 0.9;
  background: linear-gradient(90deg, transparent, rgba(56, 189, 248, 0.55), rgba(34, 211, 238, 0.55), rgba(125, 211, 252, 0.55), transparent);
}

.credit {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
  color: var(--text-muted);
  font-size: 13px;
}

.label {
  opacity: 0.8;
}

.author {
  font-weight: 700;
  letter-spacing: 0.2px;
  color: var(--accent-1);
  text-decoration: none;
}

.author:hover {
  filter: drop-shadow(0 0 10px rgba(56, 189, 248, 0.25));
}

.dot {
  opacity: 0.55;
}

.year {
  opacity: 0.75;
}

.repo {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  padding: 8px 12px;
  border: 1px solid rgba(255, 255, 255, 0.14);
  border-radius: 999px;
  background: rgba(0, 0, 0, 0.2);
  color: var(--text-main);
  text-decoration: none;
  font-size: 13px;
  line-height: 1;
  white-space: nowrap;
  transition: transform 0.15s ease, border-color 0.15s ease, box-shadow 0.15s ease, background 0.15s ease;
}

.repo:hover {
  transform: translateY(-1px);
  border-color: rgba(125, 211, 252, 0.65);
  background: rgba(0, 0, 0, 0.26);
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.35), 0 0 24px rgba(56, 189, 248, 0.1);
}

.repo:focus-visible,
#checkButton:focus-visible {
  outline: 2px solid rgba(56, 189, 248, 0.55);
  outline-offset: 2px;
}

.icon {
  width: 16px;
  height: 16px;
  display: block;
  opacity: 0.92;
}

@media (max-width: 720px) {
  .controls {
    grid-template-columns: 1fr;
  }

  #checkButton {
    min-height: 44px;
  }
}

@media (max-width: 520px) {
  .footer {
    justify-content: center;
  }

  .app {
    padding: 18px 14px 14px;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}