:root {
  --bg: #F1F4F7;
  --surface: #FFFFFF;
  --border: #D3DAE2;
  --text: #1A2330;
  --text-muted: #5C6878;
  --accent: #2C4A6B;
  --accent-light: #E8EEF5;
  --accent-mid: #3D6896;
  --warn: #7A3B3B;
  --warn-light: #F5E8E8;
  --mono: 'IBM Plex Mono', monospace;
  --sans: 'IBM Plex Sans', sans-serif;
  --radius: 4px;
  --transition: 240ms cubic-bezier(0.4, 0, 0.2, 1);
}

* { box-sizing: border-box; margin: 0; padding: 0; }

body {
  font-family: var(--sans);
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  font-size: 15px;
  line-height: 1.6;
}

.shell {
  max-width: 560px;
  margin: 0 auto;
  min-height: 100vh;
  background: var(--surface);
  border-left: 1px solid var(--border);
  border-right: 1px solid var(--border);
  display: flex;
  flex-direction: column;
}

header {
  background: var(--accent);
  color: #fff;
  padding: 20px 24px;
  position: sticky;
  top: 0;
  z-index: 10;
}

.header-eyebrow {
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  opacity: 0.7;
  margin-bottom: 4px;
}

header h1 {
  font-size: 17px;
  font-weight: 600;
  letter-spacing: -0.01em;
  line-height: 1.3;
}

main {
  flex: 1;
  padding: 28px 24px 40px;
}

h2 {
  font-size: 18px;
  font-weight: 600;
  margin-bottom: 14px;
  letter-spacing: -0.01em;
}

p { margin-bottom: 14px; }

.muted { color: var(--text-muted); font-size: 13px; }

.label {
  display: block;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: 8px;
  margin-top: 18px;
}

input[type=text], input[type=password], input[type=email], select, textarea {
  width: 100%;
  font-family: var(--sans);
  font-size: 15px;
  color: var(--text);
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 10px 12px;
  transition: border-color var(--transition);
}

textarea {
  min-height: 120px;
  resize: vertical;
  line-height: 1.5;
}

input:focus, select:focus, textarea:focus {
  outline: none;
  border-color: var(--accent);
}

button, .btn {
  display: inline-block;
  font-family: var(--sans);
  font-size: 14px;
  font-weight: 500;
  letter-spacing: 0.01em;
  color: #fff;
  background: var(--accent);
  border: none;
  border-radius: var(--radius);
  padding: 12px 22px;
  cursor: pointer;
  transition: background var(--transition);
  text-decoration: none;
}

button:hover, .btn:hover { background: var(--accent-mid); }
button:disabled { opacity: 0.5; cursor: not-allowed; }

.btn-block { display: block; width: 100%; margin-top: 20px; }

.scenario-content {
  font-size: 16px;
  line-height: 1.65;
  color: var(--text);
  margin-bottom: 22px;
}

.clues {
  background: var(--accent-light);
  border-left: 3px solid var(--accent);
  padding: 12px 16px;
  margin-bottom: 22px;
  border-radius: 0 var(--radius) var(--radius) 0;
}
.clues ul { list-style: none; }
.clues li {
  font-family: var(--mono);
  font-size: 12px;
  color: var(--accent);
  padding: 2px 0;
}

.dots {
  display: flex;
  gap: 8px;
  justify-content: center;
  margin-bottom: 24px;
}
.dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--border);
}
.dot.active { background: var(--accent); }

.error {
  background: var(--warn-light);
  border-left: 3px solid var(--warn);
  padding: 14px 16px;
  color: var(--warn);
  border-radius: 0 var(--radius) var(--radius) 0;
}

.radio-group { display: flex; flex-direction: column; gap: 8px; }
.radio-group label {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 12px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  cursor: pointer;
  font-size: 14px;
  transition: background var(--transition);
}
.radio-group label:hover { background: var(--accent-light); }
.radio-group input[type=radio] { margin: 0; }

table {
  width: 100%;
  border-collapse: collapse;
  font-size: 13px;
  margin-top: 12px;
}
th, td {
  text-align: left;
  padding: 8px 10px;
  border-bottom: 1px solid var(--border);
}
th {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--text-muted);
}

.stat {
  display: flex;
  justify-content: space-between;
  padding: 8px 0;
  border-bottom: 1px solid var(--border);
  font-size: 14px;
}
.stat strong { font-family: var(--mono); }