:root {
  --bg: #0e1620;
  --panel: #16212e;
  --panel-2: #1c2a3a;
  --border: #2a3b4d;
  --text: #e8eef4;
  --muted: #8fa3b5;
  --accent: #2f9e6e;
  --accent-hover: #37b47c;
  --danger: #d9534f;
  --danger-bg: #3a2323;
  --success-bg: #1f3a2c;
  --warn: #e0a53d;
  --radius: 14px;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
}

.app {
  max-width: 680px;
  margin: 0 auto;
  padding: 16px 16px 60px;
}

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 0 20px;
}

.topbar h1 {
  font-size: 1.25rem;
  margin: 0;
}

.ghost-btn {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--muted);
  padding: 8px 12px;
  border-radius: 10px;
  cursor: pointer;
  font-size: 0.8rem;
}
.ghost-btn:hover { border-color: var(--danger); color: var(--danger); }

.screen.hidden { display: none; }

.card {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
}

.muted { color: var(--muted); font-size: 0.92rem; line-height: 1.5; }

.stats-grid {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 8px;
  margin: 20px 0;
}
.stat-box {
  background: var(--panel-2);
  border-radius: 10px;
  padding: 10px 4px;
  text-align: center;
}
.stat-box .num { font-size: 1.3rem; font-weight: 700; display: block; }
.stat-box .lbl { font-size: 0.68rem; color: var(--muted); text-transform: uppercase; letter-spacing: 0.03em; }

.mode-select {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin: 20px 0;
  font-size: 0.92rem;
}
.mode-select label {
  display: flex;
  align-items: center;
  gap: 10px;
  background: var(--panel-2);
  padding: 10px 12px;
  border-radius: 10px;
  cursor: pointer;
  border: 1px solid transparent;
}
.mode-select input[type="radio"] { accent-color: var(--accent); width: 16px; height: 16px; }
.mode-select label:has(input:checked) { border-color: var(--accent); }

.primary-btn {
  width: 100%;
  background: var(--accent);
  color: #fff;
  border: none;
  padding: 14px;
  border-radius: 12px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  margin-top: 8px;
}
.primary-btn:hover { background: var(--accent-hover); }
.primary-btn:active { transform: scale(0.98); }

.progressbar-wrap { margin-bottom: 16px; }
.progressbar {
  height: 8px;
  background: var(--panel-2);
  border-radius: 6px;
  overflow: hidden;
}
.progressbar-fill {
  height: 100%;
  background: var(--accent);
  width: 0%;
  transition: width 0.25s ease;
}
.progress-text {
  font-size: 0.78rem;
  color: var(--muted);
  margin-top: 6px;
  text-align: right;
}

.question-card { min-height: 320px; }
.q-meta { font-size: 0.75rem; color: var(--muted); margin-bottom: 6px; }
#qText { font-size: 1.15rem; line-height: 1.4; margin: 0 0 20px; }

.options { display: flex; flex-direction: column; gap: 10px; }

.option-btn {
  text-align: left;
  background: var(--panel-2);
  border: 1px solid var(--border);
  color: var(--text);
  padding: 14px 16px;
  border-radius: 12px;
  cursor: pointer;
  font-size: 0.96rem;
  line-height: 1.4;
}
.option-btn:hover:not(:disabled) { border-color: var(--accent); }
.option-btn:disabled { cursor: default; }

.option-btn.correct {
  background: var(--success-bg);
  border-color: var(--accent);
}
.option-btn.wrong {
  background: var(--danger-bg);
  border-color: var(--danger);
}

.feedback {
  margin-top: 16px;
  padding: 12px 14px;
  border-radius: 10px;
  font-size: 0.9rem;
  line-height: 1.4;
}
.feedback.hidden { display: none; }
.feedback.ok { background: var(--success-bg); }
.feedback.bad { background: var(--danger-bg); }
.feedback .tagnote { display: block; margin-top: 6px; font-size: 0.78rem; color: var(--warn); }

@media (max-width: 420px) {
  .stats-grid { grid-template-columns: repeat(3, 1fr); }
}