:root {
  --bg: #11141a;
  --panel: #1a1f29;
  --panel-2: #222836;
  --text: #e6e9ef;
  --muted: #8b93a5;
  --accent: #4f8cff;
  --accent-2: #3a6fd8;
  --error: #ff6b6b;
  --correct: #4ade80;
  --wrong: #ff6b6b;
  --border: #2c3344;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.5;
}

header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 20px;
  border-bottom: 1px solid var(--border);
  background: var(--panel);
}

.brand { font-weight: 700; font-size: 1.1rem; letter-spacing: 0.02em; }

nav { display: flex; gap: 8px; }

main {
  max-width: 720px;
  margin: 0 auto;
  padding: 28px 20px 60px;
}

h1 { font-size: 1.5rem; margin: 0 0 8px; }

.hidden { display: none !important; }
.muted { color: var(--muted); font-size: 0.92rem; }
.error { color: var(--error); margin-top: 10px; }

form { margin-top: 14px; }

input[type="password"],
input[type="text"],
textarea {
  width: 100%;
  padding: 10px 12px;
  margin-bottom: 10px;
  background: var(--panel-2);
  border: 1px solid var(--border);
  border-radius: 6px;
  color: var(--text);
  font-size: 1rem;
  font-family: inherit;
}
textarea { resize: vertical; }

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

button {
  padding: 9px 16px;
  background: var(--panel-2);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 6px;
  font-size: 0.95rem;
  cursor: pointer;
  font-family: inherit;
}
button:hover { border-color: var(--accent); }
button.primary, button[type="submit"] { background: var(--accent-2); border-color: var(--accent-2); }
button:disabled { opacity: 0.6; cursor: not-allowed; }

.card-list { display: flex; flex-direction: column; gap: 12px; margin-top: 16px; }

.card {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 14px 16px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}
.card-title { font-weight: 600; }

.question {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 14px 16px;
  margin: 14px 0;
}
.q-prompt { font-weight: 600; margin-bottom: 8px; }

.options { display: flex; flex-direction: column; gap: 6px; }
.opt { display: flex; align-items: center; gap: 8px; cursor: pointer; }
.opt input { accent-color: var(--accent); }

.opt-line { display: block; padding: 2px 0; }
.opt-line.correct { color: var(--correct); }
.opt-line.wrong { color: var(--wrong); }

.answer-text, .reference { margin: 8px 0; }
.reference strong { color: var(--accent); }
.answer-text span { white-space: pre-wrap; }
.explanation {
  margin-top: 8px;
  padding: 8px 10px;
  border-left: 3px solid var(--accent);
  background: var(--panel-2);
  border-radius: 0 6px 6px 0;
  font-size: 0.92rem;
}

.score { font-size: 1.25rem; font-weight: 700; margin: 8px 0; }