:root {
  --taxi-yellow: #F5B700;
  --taxi-yellow-deep: #E0A500;
  --asphalt: #1E2124;
  --asphalt-soft: #2B2F33;
  --lane-white: #F4F4F0;
  --lane-dim: #9A9DA1;
  --go-green: #2E9E4F;
  --stop-red: #D6432C;
  --card: #FFFFFF;
  --radius: 10px;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--asphalt);
  color: var(--lane-white);
  font-family: "Microsoft JhengHei", "PingFang TC", "Noto Sans TC", "Heiti TC", sans-serif;
  min-height: 100vh;
}

body {
  background-image:
    repeating-linear-gradient(0deg, transparent 0 64px, rgba(244,244,240,0.035) 64px 66px);
}

.app {
  max-width: 980px;
  margin: 0 auto;
  padding: 20px 20px 40px;
}

header.top {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding: 4px 4px 18px;
  border-bottom: 3px dashed var(--taxi-yellow);
  margin-bottom: 18px;
}

header.top .badge {
  background: var(--taxi-yellow);
  color: var(--asphalt);
  font-weight: 700;
  font-size: 13px;
  padding: 4px 10px;
  border-radius: 999px;
  letter-spacing: 1px;
}

header.top h1 {
  font-size: 22px;
  margin: 0;
  color: var(--lane-white);
  font-weight: 700;
}

header.top .sub {
  color: var(--lane-dim);
  font-size: 13px;
  margin-left: auto;
}

/* Category bar */
#categoryBar {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 20px;
}

.cat-btn {
  appearance: none;
  border: 2px solid var(--asphalt-soft);
  background: var(--asphalt-soft);
  color: var(--lane-white);
  padding: 10px 18px;
  border-radius: 999px;
  font-size: 15px;
  font-family: inherit;
  cursor: pointer;
  transition: background 0.15s, border-color 0.15s, color 0.15s, transform 0.1s;
}

.cat-btn:hover { border-color: var(--taxi-yellow); }
.cat-btn:active { transform: scale(0.97); }

.cat-btn.active {
  background: var(--taxi-yellow);
  border-color: var(--taxi-yellow);
  color: var(--asphalt);
  font-weight: 700;
}

/* Question card */
.question-card {
  background: var(--card);
  color: var(--asphalt);
  border-radius: var(--radius);
  padding: 26px 28px 22px;
  position: relative;
  box-shadow: 0 10px 30px rgba(0,0,0,0.35);
  min-height: 240px;
}

.question-card::before {
  content: "";
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 6px;
  background: repeating-linear-gradient(90deg, var(--taxi-yellow) 0 26px, var(--asphalt) 26px 34px);
  border-radius: var(--radius) var(--radius) 0 0;
}

.q-head {
  display: flex;
  gap: 14px;
  align-items: flex-start;
  padding-top: 6px;
}

#txtExamNumber {
  font-size: 26px;
  font-weight: 800;
  color: var(--taxi-yellow-deep);
  flex: none;
  padding-top: 2px;
}

#txtQuestionText {
  flex: 1;
  border: none;
  outline: none;
  resize: none;
  font-size: 20px;
  line-height: 1.5;
  font-family: inherit;
  color: var(--asphalt);
  background: transparent;
  width: 100%;
  min-height: 3.4em;
}

.options {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin: 14px 0 10px;
}

.opt {
  font-size: 19px;
  padding: 8px 12px;
  border-radius: 6px;
  line-height: 1.4;
}

#txtQuestionTextTail {
  font-size: 19px;
  color: var(--asphalt);
  padding: 4px 0 0;
  min-height: 1.4em;
}

/* Answer row */
.answer-row {
  display: grid;
  gap: 14px;
  margin: 22px 0 24px;
}

#answerChoice { grid-template-columns: repeat(3, 1fr); gap: 18px; }
#answerTF { grid-template-columns: repeat(2, 1fr); gap: 18px; }

.answer-row.hidden { display: none; }

.ans-btn {
  appearance: none;
  border: 3px solid #C7CACD;
  background: var(--card);
  color: var(--asphalt);
  border-radius: var(--radius);
  display: flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  height: 62px;
  font-size: 44px;
  font-weight: 800;
  font-family: inherit;
  cursor: pointer;
  transition: background 0.12s, border-color 0.12s, transform 0.08s;
}

.ans-btn:hover { border-color: var(--taxi-yellow); }
.ans-btn:active { transform: scale(0.97); }

.ans-btn.selected {
  background: var(--go-green);
  border-color: var(--go-green);
  color: white;
}

/* Exam number grid */
.section-label {
  font-size: 13px;
  color: var(--lane-dim);
  letter-spacing: 2px;
  margin: 6px 0 8px;
  text-transform: uppercase;
}

#examNumbers {
  display: grid;
  grid-template-columns: repeat(10, 1fr);
  gap: 6px;
  margin-bottom: 10px;
}

.num-btn {
  appearance: none;
  border: 2px solid var(--asphalt-soft);
  background: var(--asphalt-soft);
  color: var(--lane-white);
  border-radius: 6px;
  height: 44px;
  font-size: 16px;
  font-family: inherit;
  cursor: pointer;
  transition: background 0.12s, border-color 0.12s;
}

.num-btn:hover { border-color: var(--taxi-yellow); }
.num-btn.answered { background: var(--go-green); border-color: var(--go-green); color: white; }
.num-btn.wrong { border-color: var(--stop-red); border-width: 2px; }

/* Footer controls */
footer.controls {
  display: flex;
  align-items: center;
  gap: 16px;
}

#btnFinish {
  appearance: none;
  border: none;
  background: var(--taxi-yellow);
  color: var(--asphalt);
  font-weight: 800;
  font-size: 18px;
  font-family: inherit;
  padding: 12px 28px;
  border-radius: 999px;
  cursor: pointer;
  transition: transform 0.08s, background 0.12s;
}

#btnFinish:hover { background: var(--taxi-yellow-deep); }
#btnFinish:active { transform: scale(0.97); }

#scoreSummary {
  font-size: 16px;
  font-weight: 700;
  color: var(--lane-white);
}

@media (max-width: 640px) {
  #examNumbers { grid-template-columns: repeat(5, 1fr); }
  .ans-btn { font-size: 32px; height: 68px; }
  #answerChoice, #answerTF { gap: 10px; }
  #txtQuestionText { font-size: 18px; }
}