:root {
  --bg: #0f1420;
  --card: #1a2233;
  --card2: #212c42;
  --accent: #ff7a45;
  --accent2: #5fd0ff;
  --text: #eef1f7;
  --text-dim: #9aa5b8;
  --ok: #5fd67d;
  --bad: #ff5f6d;
  --radius: 16px;
}
* { box-sizing: border-box; }
html, body {
  margin: 0; padding: 0; background: var(--bg); color: var(--text);
  font-family: -apple-system, "PingFang TC", "Noto Sans TC", "Microsoft JhengHei", sans-serif;
  min-height: 100vh;
}
#app { max-width: 900px; margin: 0 auto; padding: 24px 16px 80px; }

.header {
  text-align: center; padding: 24px 0 8px;
}
.header h1 { font-size: 1.6rem; margin: 0 0 6px; }
.header p { color: var(--text-dim); margin: 0; font-size: 0.95rem; }

.progress-bar-wrap {
  background: var(--card); border-radius: 999px; height: 10px; overflow: hidden; margin: 16px 0 28px;
}
.progress-bar-fill {
  height: 100%; background: linear-gradient(90deg, var(--accent), var(--accent2));
  transition: width .3s ease;
}

.grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(180px, 1fr)); gap: 14px;
}
.stage-card {
  background: var(--card); border-radius: var(--radius); padding: 18px 14px;
  cursor: pointer; border: 2px solid transparent; transition: transform .15s, border-color .15s;
  display: flex; flex-direction: column; gap: 6px; position: relative;
}
.stage-card:hover { transform: translateY(-3px); border-color: var(--accent); }
.stage-card.locked { opacity: .4; cursor: not-allowed; }
.stage-card.locked:hover { transform: none; border-color: transparent; }
.stage-card.passed { border-color: var(--ok); }
.stage-icon { font-size: 1.8rem; }
.stage-title { font-weight: 600; font-size: 0.98rem; }
.stage-status { font-size: 0.78rem; color: var(--text-dim); }
.badge-done {
  position: absolute; top: 10px; right: 10px; background: var(--ok); color: #06210f;
  font-size: 0.7rem; font-weight: 700; padding: 2px 8px; border-radius: 999px;
}

.panel {
  background: var(--card); border-radius: var(--radius); padding: 22px; margin-top: 18px;
}
.reading-text { line-height: 1.9; font-size: 1rem; color: #dfe4ee; white-space: pre-wrap; }
.btn {
  display: inline-block; background: var(--accent); color: #201200; font-weight: 700;
  border: none; border-radius: 10px; padding: 12px 22px; font-size: 1rem; cursor: pointer;
  margin-top: 18px;
}
.btn.secondary { background: var(--card2); color: var(--text); }
.btn:disabled { opacity: .5; cursor: not-allowed; }

.q-progress { color: var(--text-dim); font-size: 0.85rem; margin-bottom: 8px; }
.q-text { font-size: 1.12rem; font-weight: 600; margin-bottom: 16px; line-height: 1.6; }
.option {
  display: block; width: 100%; text-align: left; background: var(--card2); color: var(--text);
  border: 2px solid transparent; border-radius: 12px; padding: 14px 16px; margin-bottom: 10px;
  cursor: pointer; font-size: 0.98rem; line-height: 1.5;
}
.option:hover { border-color: var(--accent2); }
.option.correct { border-color: var(--ok); background: #163825; }
.option.wrong { border-color: var(--bad); background: #3a1a1d; }
.option.disabled { pointer-events: none; }
.explain-box {
  margin-top: 14px; padding: 14px; border-radius: 12px; background: #10182a;
  font-size: 0.92rem; color: var(--text-dim); border-left: 3px solid var(--accent2);
}

.result-score { font-size: 2.4rem; font-weight: 800; text-align: center; margin: 12px 0; }
.result-msg { text-align: center; color: var(--text-dim); margin-bottom: 20px; }
.pass { color: var(--ok); }
.fail { color: var(--bad); }

.cert-form input {
  width: 100%; padding: 12px 14px; border-radius: 10px; border: 1px solid #334;
  background: #0d1322; color: var(--text); font-size: 1rem; margin-bottom: 12px;
}
.cert-canvas-wrap { text-align: center; margin-top: 16px; }
#certCanvas { max-width: 100%; border-radius: 12px; box-shadow: 0 10px 30px rgba(0,0,0,.4); }

.footer-nav { display: flex; justify-content: space-between; margin-top: 20px; }

@media (max-width: 480px) {
  .grid { grid-template-columns: repeat(2, 1fr); }
  .header h1 { font-size: 1.3rem; }
}