:root {
  --primary: #d9a441;
  --primary-dark: #c28f34;
  --accent: #2f6a54;
  --accent-dark: #1f4a3d;
  --ink-on-gold: #4a3413;
  --success: #16a34a;
  --danger: #dc2626;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  min-height: 100vh;
  font-family: 'Karla', sans-serif;
  background: radial-gradient(circle at top, var(--accent) 0%, var(--accent-dark) 70%);
  color: #eef0ea;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 24px;
}

.wrap {
  width: 100%;
  max-width: 520px;
  position: relative;
}

.back-link {
  display: inline-block;
  margin-bottom: 20px;
  color: #eef0ea;
  text-decoration: none;
  font-size: 14px;
  opacity: 0.8;
}
.back-link:hover { opacity: 1; }

.header-row {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-bottom: 18px;
  flex-wrap: wrap;
}
.header-icon {
  width: 44px;
  height: 44px;
  border-radius: 12px;
  background: rgba(217, 164, 65, 0.15);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 22px;
  flex-shrink: 0;
}
.title {
  font-family: 'Bitter', serif;
  font-size: 21px;
  margin: 0 0 2px;
  color: #fff;
}
.subtitle {
  font-size: 13px;
  opacity: 0.8;
  margin: 0;
}
.header-actions {
  margin-left: auto;
  display: flex;
  align-items: center;
  gap: 10px;
}
.score-chip {
  font-size: 13px;
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid rgba(217, 164, 65, 0.3);
  border-radius: 999px;
  padding: 6px 12px;
}
.score-chip strong { color: var(--primary); font-family: 'JetBrains Mono', monospace; }
.restart-btn {
  border: 1px solid rgba(217, 164, 65, 0.4);
  background: transparent;
  color: #eef0ea;
  border-radius: 10px;
  padding: 7px 14px;
  font-size: 13px;
  font-weight: 700;
  cursor: pointer;
}
.restart-btn:hover { background: var(--primary); border-color: var(--primary); color: var(--ink-on-gold); }

.progress-dots {
  display: flex;
  gap: 5px;
  margin-bottom: 8px;
  flex-wrap: wrap;
}
.dot {
  width: 18px;
  height: 6px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.15);
}
.dot.current { background: var(--primary); }
.dot.correct { background: var(--success); }
.dot.wrong { background: var(--danger); }

.stage-label {
  font-size: 12px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--primary);
  font-weight: 700;
  margin-bottom: 16px;
}

.problem-card {
  background: rgba(217, 164, 65, 0.1);
  border: 1px solid rgba(217, 164, 65, 0.3);
  border-radius: 16px;
  padding: 32px 20px;
  text-align: center;
  margin-bottom: 16px;
}
.problem {
  font-family: 'JetBrains Mono', monospace;
  font-size: 32px;
  font-weight: 700;
  color: #fff;
}

.options-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
}
.option-btn {
  padding: 20px 8px;
  border-radius: 12px;
  border: 2px solid rgba(217, 164, 65, 0.35);
  background: rgba(255, 255, 255, 0.06);
  color: #fff;
  font-family: 'JetBrains Mono', monospace;
  font-size: 22px;
  font-weight: 700;
  cursor: pointer;
  transition: all 0.15s ease;
}
.option-btn:hover:not(:disabled) { border-color: var(--primary); background: rgba(217, 164, 65, 0.15); }
.option-btn:disabled { cursor: default; }
.option-btn.correct { background: rgba(22, 163, 74, 0.35); border-color: var(--success); }
.option-btn.wrong { background: rgba(220, 38, 38, 0.35); border-color: var(--danger); }

.end-banner {
  margin-top: 18px;
  padding: 14px 16px;
  border-radius: 12px;
  background: rgba(217, 164, 65, 0.15);
  border: 1px solid var(--primary);
  text-align: center;
  font-size: 14px;
}
.end-banner strong { color: var(--primary); font-family: 'JetBrains Mono', monospace; }
.hidden { display: none; }