:root {
  --bg: #0a0e1a;
  --bg-2: #111729;
  --ink: #e7ecff;
  --ink-dim: #8a93b8;
  --accent: #00ffd1;
  --accent-2: #b14bff;
  --good: #2ee27a;
  --bad: #ff4d6d;
  --grid: rgba(255, 255, 255, 0.04);
  --card: rgba(255, 255, 255, 0.04);
  --card-border: rgba(255, 255, 255, 0.08);
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, monospace;
  min-height: 100vh;
  overscroll-behavior: none;
}

body {
  background:
    radial-gradient(circle at 15% 10%, rgba(0, 255, 209, 0.08), transparent 40%),
    radial-gradient(circle at 85% 90%, rgba(177, 75, 255, 0.08), transparent 40%),
    linear-gradient(180deg, var(--bg) 0%, var(--bg-2) 100%);
  background-attachment: fixed;
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  background-image:
    linear-gradient(var(--grid) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid) 1px, transparent 1px);
  background-size: 40px 40px;
  pointer-events: none;
  z-index: 0;
}

.wrap {
  position: relative;
  z-index: 1;
  max-width: 1400px;
  margin: 0 auto;
  padding: 24px;
}

h1,
h2,
h3 {
  letter-spacing: 0.02em;
  margin: 0;
}

h1 {
  font-size: clamp(28px, 4vw, 56px);
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.tag {
  display: inline-block;
  font-size: 12px;
  padding: 4px 10px;
  border-radius: 999px;
  border: 1px solid var(--card-border);
  color: var(--ink-dim);
  text-transform: uppercase;
  letter-spacing: 0.18em;
}

.card {
  background: var(--card);
  border: 1px solid var(--card-border);
  border-radius: 16px;
  padding: 24px;
  backdrop-filter: blur(6px);
}

.btn {
  font: inherit;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  padding: 14px 22px;
  border-radius: 12px;
  border: 1px solid var(--accent);
  background: transparent;
  color: var(--accent);
  cursor: pointer;
  transition: transform 0.08s, background 0.12s;
}
.btn:hover {
  background: rgba(0, 255, 209, 0.1);
}
.btn:active {
  transform: translateY(1px);
}
.btn.primary {
  background: var(--accent);
  color: #06121a;
}
.btn.primary:hover {
  background: #4cffe0;
}
.btn.ghost {
  border-color: var(--card-border);
  color: var(--ink-dim);
}
.btn:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

.input {
  font: inherit;
  background: rgba(0, 0, 0, 0.3);
  border: 1px solid var(--card-border);
  color: var(--ink);
  padding: 14px 16px;
  border-radius: 12px;
  width: 100%;
}
.input:focus {
  outline: none;
  border-color: var(--accent);
}

.row {
  display: flex;
  gap: 12px;
  align-items: center;
  flex-wrap: wrap;
}

.choices {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}
@media (max-width: 600px) {
  .choices {
    grid-template-columns: 1fr;
  }
}

.choice {
  position: relative;
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 20px;
  border-radius: 14px;
  border: 1px solid var(--card-border);
  background: rgba(255, 255, 255, 0.03);
  font-size: clamp(18px, 2vw, 24px);
  cursor: pointer;
  transition: transform 0.08s, border-color 0.12s, background 0.12s;
  text-align: left;
  color: var(--ink);
  font-family: inherit;
}
.choice:hover {
  border-color: var(--accent);
}
.choice .key {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: 10px;
  background: rgba(0, 255, 209, 0.12);
  color: var(--accent);
  font-weight: 700;
  flex-shrink: 0;
}
.choice.locked {
  border-color: var(--accent-2);
  background: rgba(177, 75, 255, 0.1);
}
.choice.correct {
  border-color: var(--good);
  background: rgba(46, 226, 122, 0.14);
}
.choice.wrong {
  border-color: var(--bad);
  background: rgba(255, 77, 109, 0.14);
}
.choice:disabled {
  cursor: default;
}

.kbd {
  font-size: 11px;
  color: var(--ink-dim);
  border: 1px solid var(--card-border);
  padding: 2px 6px;
  border-radius: 4px;
}

.dim {
  color: var(--ink-dim);
}

.center {
  text-align: center;
}

.flex-col {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.muted-card {
  background: rgba(255, 255, 255, 0.02);
  border: 1px dashed var(--card-border);
  border-radius: 12px;
  padding: 16px;
}

@keyframes pulse {
  0%,
  100% {
    opacity: 1;
  }
  50% {
    opacity: 0.4;
  }
}
.pulse {
  animation: pulse 1.4s ease-in-out infinite;
}

@keyframes flash-good {
  0% {
    background: rgba(46, 226, 122, 0);
  }
  20% {
    background: rgba(46, 226, 122, 0.25);
  }
  100% {
    background: rgba(46, 226, 122, 0);
  }
}
@keyframes flash-bad {
  0% {
    background: rgba(255, 77, 109, 0);
  }
  20% {
    background: rgba(255, 77, 109, 0.25);
  }
  100% {
    background: rgba(255, 77, 109, 0);
  }
}
.flash-good {
  animation: flash-good 0.8s ease-out;
}
.flash-bad {
  animation: flash-bad 0.8s ease-out;
}