/* ═══════════════════════════════════════════════════════
   Test Prep — formal exam look, iPad-first
   ═══════════════════════════════════════════════════════ */

:root {
  --bg: #131a25;
  --bg-2: #1c2533;
  --bg-3: #28344a;
  --ink: #e8eef5;
  --ink-dim: #8696b0;
  --accent: #5fa8d8;
  --accent-soft: rgba(95, 168, 216, 0.15);
  --green: #5cc28d;
  --green-soft: rgba(92, 194, 141, 0.15);
  --amber: #f0b86e;
  --red: #e07b6b;
  --shadow: 0 6px 24px rgba(0, 0, 0, 0.35);
  --radius: 14px;
}

* { box-sizing: border-box; -webkit-tap-highlight-color: transparent; }
html, body {
  margin: 0; padding: 0; height: 100%;
  background: var(--bg);
  color: var(--ink);
  font-family: -apple-system, "Segoe UI", "PingFang SC", "Hiragino Sans", sans-serif;
  font-size: 17px;
  line-height: 1.5;
  overflow: hidden;
  overscroll-behavior: none;
  -webkit-user-select: none;
  user-select: none;
}
textarea, input { user-select: text; -webkit-user-select: text; }
button { font: inherit; color: inherit; border: 0; background: transparent; cursor: pointer; }

.screen { position: absolute; inset: 0; display: none; flex-direction: column; padding: env(safe-area-inset-top, 0) 0 env(safe-area-inset-bottom, 0); overflow-y: auto; -webkit-overflow-scrolling: touch; }
.screen.active { display: flex; animation: fadeIn 300ms ease-out; }

/* fill-number (auto-graded numeric) */
.fillnum-row { display: flex; align-items: center; gap: 10px; margin-top: 14px; flex-wrap: wrap; }
.fillnum-input { width: 130px; padding: 11px 12px; font-size: 19px; border-radius: 10px; border: 2px solid var(--bg-3); background: var(--bg); color: var(--ink); text-align: center; }
.fillnum-input:focus { outline: none; border-color: var(--accent); }
.fillnum-input.correct { border-color: var(--green); color: var(--green); }
.fillnum-input.wrong { border-color: var(--red); color: var(--red); }
.fillnum-unit { font-size: 16px; color: var(--ink-dim); }
.fillnum-check { padding: 11px 20px; border-radius: 10px; background: var(--accent); color: #fff; font-size: 15px; font-weight: 600; }
.fillnum-check:active { opacity: 0.8; }
@keyframes fadeIn { from { opacity: 0; transform: translateY(6px); } to { opacity: 1; transform: none; } }

/* ═══════════════ HOME ═══════════════ */
.home-hero {
  padding: 40px 32px 16px; text-align: center;
}
.hero-emoji { font-size: 64px; line-height: 1; }
.home-hero h1 {
  margin: 12px 0 4px; font-size: 36px; font-weight: 700;
  font-family: Georgia, serif;
}
.subtitle { margin: 0; color: var(--ink-dim); font-size: 15px; }
.hero-note {
  max-width: 480px; margin: 14px auto 0;
  color: var(--ink-dim); font-size: 14px;
}

.quiz-grid {
  flex: 1; padding: 24px 32px;
  display: grid; grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
  gap: 18px;
  align-content: start;
}
.quiz-card {
  background: var(--bg-2);
  border-radius: var(--radius);
  padding: 24px;
  border: 2px solid transparent;
  transition: transform 160ms, border-color 160ms;
}
.quiz-card.done { border-color: var(--green); }
.quiz-card:active { transform: scale(0.98); }
.qc-roman {
  display: inline-block;
  background: var(--bg-3);
  color: var(--ink-dim);
  font-family: Georgia, serif;
  padding: 4px 12px;
  border-radius: 6px;
  font-size: 14px;
  letter-spacing: 1px;
  margin-bottom: 12px;
}
.qc-title { font-size: 22px; font-weight: 600; margin-bottom: 6px; }
.qc-chapter { color: var(--ink-dim); font-size: 14px; margin-bottom: 14px; }
.qc-stats {
  display: flex; gap: 16px; align-items: center;
  margin-top: 16px;
  padding-top: 14px;
  border-top: 1px solid var(--bg-3);
}
.qc-bestscore { font-size: 22px; font-weight: 700; color: var(--accent); }
.qc-bestscore .total { color: var(--ink-dim); font-weight: 500; font-size: 16px; }
.qc-grade {
  display: inline-block; padding: 4px 12px; border-radius: 6px;
  font-weight: 700; font-size: 18px;
}
.qc-grade.A { background: rgba(92, 194, 141, 0.18); color: var(--green); }
.qc-grade.B { background: rgba(95, 168, 216, 0.18); color: var(--accent); }
.qc-grade.C { background: rgba(240, 184, 110, 0.18); color: var(--amber); }
.qc-grade.D, .qc-grade.F { background: rgba(224, 123, 107, 0.18); color: var(--red); }
.qc-attempts { color: var(--ink-dim); font-size: 13px; margin-left: auto; }
.qc-start { color: var(--accent); font-size: 15px; margin-top: 8px; }

.home-footer {
  padding: 16px 32px env(safe-area-inset-bottom, 16px);
  display: flex; justify-content: center;
}
.btn-ghost {
  background: var(--bg-2);
  padding: 12px 18px;
  border-radius: 10px;
  color: var(--ink);
  font-size: 14px;
}
.btn-ghost.danger { color: var(--red); }

/* ═══════════════ Header ═══════════════ */
.mission-header {
  display: flex; align-items: center; gap: 16px;
  padding: 14px 24px;
  background: var(--bg);
  border-bottom: 1px solid var(--bg-3);
}
.btn-back {
  font-size: 16px; padding: 8px 12px; border-radius: 8px;
  color: var(--ink-dim); min-width: 70px; text-align: left;
}
.btn-back:active { background: var(--bg-2); }
.mission-title {
  flex: 1; text-align: center; font-size: 16px; font-weight: 600;
  font-family: Georgia, serif;
}
.mission-progress { min-width: 70px; text-align: right; font-size: 13px; color: var(--ink-dim); }

/* ═══════════════ Intro screen ═══════════════ */
.intro-body { flex: 1; overflow-y: auto; padding: 24px 32px; display: flex; justify-content: center; }
.intro-card {
  background: var(--bg-2);
  border-radius: var(--radius);
  padding: 28px 32px;
  max-width: 560px; width: 100%;
}
.intro-card h2 { font-family: Georgia, serif; margin: 0 0 8px; font-size: 24px; }
.intro-card .chapter { color: var(--ink-dim); font-size: 14px; margin-bottom: 20px; }
.intro-card .section-list {
  display: flex; flex-direction: column; gap: 8px;
  margin: 20px 0 24px;
}
.intro-card .section-row {
  display: flex; align-items: baseline; gap: 12px;
  padding: 10px 14px;
  background: var(--bg-3);
  border-radius: 8px;
}
.intro-card .sr-roman {
  font-family: Georgia, serif; font-weight: 600;
  min-width: 28px; color: var(--accent);
}
.intro-card .sr-title { flex: 1; }
.intro-card .sr-pts { color: var(--ink-dim); font-size: 14px; }
.intro-card .total-pts {
  text-align: right; font-weight: 600; font-size: 18px;
  color: var(--ink); margin-top: 8px;
}
.btn-primary {
  background: var(--accent); color: #0e1622; font-weight: 600;
  padding: 14px 28px; border-radius: 12px; font-size: 17px;
  width: 100%; margin-top: 16px;
  transition: transform 160ms;
}
.btn-primary:active { transform: scale(0.98); }
.btn-primary:disabled { opacity: 0.4; cursor: not-allowed; }

/* ═══════════════ Section body ═══════════════ */
.section-body {
  flex: 1; overflow-y: auto; padding: 24px 28px 16px;
  display: flex; flex-direction: column; gap: 16px;
}
.section-instructions {
  padding: 12px 16px;
  background: var(--accent-soft);
  border-left: 3px solid var(--accent);
  border-radius: 8px;
  font-size: 14px; color: #cce0f0;
  line-height: 1.5;
}

.q-card {
  background: var(--bg-2);
  border-radius: var(--radius);
  padding: 20px 22px;
}
.q-num {
  display: inline-block;
  background: var(--bg-3); color: var(--ink-dim);
  padding: 3px 10px; border-radius: 6px;
  font-size: 13px; font-weight: 600; margin-bottom: 10px;
}
.q-num .pts { color: var(--accent); margin-left: 6px; font-weight: 500; }
.q-prompt { font-size: 17px; line-height: 1.5; margin-bottom: 16px; }
.q-prompt u { text-decoration: underline; text-decoration-color: var(--amber); text-decoration-thickness: 2px; }

/* word bank */
.word-bank {
  background: var(--bg-3);
  border: 2px solid var(--bg-3);
  border-radius: 12px;
  padding: 14px;
  margin-bottom: 8px;
}
.wb-title {
  font-size: 12px; text-transform: uppercase; letter-spacing: 1.5px;
  color: var(--ink-dim); margin-bottom: 10px; font-weight: 600;
}
.wb-grid {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 8px;
}
.wb-item {
  background: var(--bg-2); padding: 8px 12px; border-radius: 8px;
  font-size: 14px;
}
.wb-letter { color: var(--accent); font-weight: 700; margin-right: 6px; }

.vocab-q {
  background: var(--bg-2); padding: 14px 16px; border-radius: 10px;
  display: flex; align-items: flex-start; gap: 12px;
}
.vocab-q-num { color: var(--ink-dim); font-size: 13px; min-width: 24px; padding-top: 2px; }
.vocab-q-text { flex: 1; font-size: 15px; line-height: 1.5; }
.vocab-q-input {
  width: 48px; height: 48px;
  border: 2px solid var(--bg-3);
  background: var(--bg);
  color: var(--ink);
  font-size: 22px; font-weight: 700; text-align: center;
  border-radius: 10px;
  text-transform: uppercase;
  outline: none;
}
.vocab-q-input:focus { border-color: var(--accent); }
.vocab-q-input.correct { border-color: var(--green); background: var(--green-soft); color: var(--green); }
.vocab-q-input.wrong { border-color: var(--red); background: rgba(224, 123, 107, 0.1); color: var(--red); }
.vocab-q .answer-hint {
  display: none; color: var(--green); font-weight: 600; margin-left: 8px;
}
.vocab-q.locked.wrong-q .answer-hint { display: inline; }
.vocab-q.bonus::after {
  content: 'BONUS'; font-size: 10px; padding: 2px 6px; border-radius: 4px;
  background: rgba(240, 184, 110, 0.2); color: var(--amber);
  margin-left: 8px; align-self: flex-start;
}

/* MCQ4 options */
.opt-list { display: flex; flex-direction: column; gap: 10px; }
.opt4 {
  background: var(--bg-3); padding: 14px 16px; border-radius: 10px;
  text-align: left; border: 2px solid transparent;
  display: flex; align-items: center; gap: 12px;
  font-size: 16px; line-height: 1.4;
  min-height: 52px;
  transition: all 160ms;
}
.opt4:active:not(.locked) { transform: scale(0.99); background: #2f3d56; }
.opt4 .letter {
  font-weight: 700; color: var(--accent); min-width: 24px;
}
.opt4.selected { border-color: var(--accent); background: var(--accent-soft); }
.opt4.correct { border-color: var(--green); background: var(--green-soft); }
.opt4.correct .letter { color: var(--green); }
.opt4.wrong { border-color: var(--red); background: rgba(224, 123, 107, 0.1); }
.opt4.locked { pointer-events: none; }

/* TF + correction */
.tf-row { display: flex; gap: 12px; margin: 14px 0; }
.tf-btn {
  flex: 1; padding: 16px;
  background: var(--bg-3); border-radius: 12px;
  font-size: 17px; font-weight: 600;
  border: 2px solid transparent;
}
.tf-btn:active:not(.locked) { transform: scale(0.97); }
.tf-btn.selected { border-color: var(--accent); background: var(--accent-soft); }
.tf-btn.correct { border-color: var(--green); background: var(--green-soft); color: #b8e8cf; }
.tf-btn.wrong { border-color: var(--red); background: rgba(224, 123, 107, 0.1); color: #f0c0b8; }
.tf-btn.locked { pointer-events: none; }

.correction-section {
  margin-top: 14px; padding-top: 14px; border-top: 1px dashed var(--bg-3);
}
.correction-label {
  font-size: 13px; color: var(--ink-dim);
  text-transform: uppercase; letter-spacing: 1px;
  margin-bottom: 10px;
}

/* Short / Critical answer */
.answer-textarea {
  width: 100%;
  min-height: 110px;
  background: var(--bg-3);
  color: var(--ink);
  border: 2px solid var(--bg-3);
  border-radius: 10px;
  padding: 14px;
  font-size: 16px; line-height: 1.5;
  font-family: inherit;
  resize: vertical;
  outline: none;
}
.answer-textarea:focus { border-color: var(--accent); }
.answer-textarea.locked { opacity: 0.7; }

.model-answer {
  margin-top: 14px;
  background: var(--green-soft);
  border-left: 3px solid var(--green);
  border-radius: 10px;
  padding: 14px 16px;
  animation: fadeIn 300ms ease-out;
}
.ma-label {
  font-size: 12px; text-transform: uppercase; letter-spacing: 1px;
  color: var(--green); font-weight: 600; margin-bottom: 8px;
}
.ma-text { font-size: 15px; line-height: 1.6; color: #d5e8dc; }

.self-rate {
  margin-top: 14px;
  background: var(--bg-3);
  border-radius: 10px;
  padding: 14px;
}
.sr-q { font-size: 14px; color: var(--ink-dim); margin-bottom: 10px; }
.sr-buttons { display: flex; gap: 8px; flex-wrap: wrap; }
.sr-btn {
  flex: 1; min-width: 100px;
  padding: 12px 10px;
  background: var(--bg-2);
  border-radius: 8px;
  font-size: 14px;
  border: 2px solid transparent;
}
.sr-btn:active { transform: scale(0.97); }
.sr-btn.full { border-color: var(--green); color: var(--green); }
.sr-btn.partial { border-color: var(--amber); color: var(--amber); }
.sr-btn.none { border-color: var(--red); color: var(--red); }
.sr-btn.selected { background: var(--bg); }
.sr-btn .sr-pts { display: block; font-size: 12px; opacity: 0.7; margin-top: 2px; }

/* Diagrams */
.diagram-box {
  background: #f5f5f0;
  color: #1a1a1a;
  border-radius: 12px;
  padding: 16px;
  margin-bottom: 14px;
  text-align: center;
}
.diagram-box svg { max-width: 100%; height: auto; }
.diagram-caption {
  font-size: 13px; color: #555; margin-top: 8px; font-style: italic;
}

/* Section footer (navigation) */
.section-footer {
  padding: 14px 24px env(safe-area-inset-bottom, 14px);
  border-top: 1px solid var(--bg-3);
  display: flex; gap: 12px; align-items: center;
}
.section-footer .spacer { flex: 1; }
.btn-next {
  background: var(--accent); color: #0e1622; font-weight: 600;
  padding: 14px 28px; border-radius: 10px; font-size: 16px;
  min-width: 140px;
}
.btn-next:active { transform: scale(0.97); }
.btn-next:disabled { opacity: 0.4; cursor: not-allowed; }
.btn-link {
  color: var(--ink-dim); font-size: 14px; padding: 8px 12px;
}

/* Results screen */
#screen-results { justify-content: center; align-items: center; padding: 24px; overflow-y: auto; }
.results-card {
  background: var(--bg-2); border-radius: 16px;
  padding: 32px 28px; max-width: 560px; width: 100%;
  box-shadow: var(--shadow);
  animation: popIn 400ms cubic-bezier(.2,1.4,.4,1);
}
@keyframes popIn { from { opacity: 0; transform: scale(0.92); } to { opacity: 1; transform: none; } }
.rc-title { font-family: Georgia, serif; font-size: 22px; text-align: center; margin: 0 0 6px; }
.rc-subtitle { text-align: center; color: var(--ink-dim); font-size: 14px; margin-bottom: 22px; }
.rc-score-row {
  text-align: center; margin: 18px 0;
}
.rc-score {
  font-size: 72px; font-weight: 800; line-height: 1;
  font-family: Georgia, serif;
}
.rc-out-of { color: var(--ink-dim); font-size: 24px; margin-left: 4px; font-weight: 500; }
.rc-grade-badge {
  display: inline-block; padding: 8px 24px; border-radius: 10px;
  font-size: 28px; font-weight: 700; margin-top: 12px;
  font-family: Georgia, serif;
}
.rc-grade-badge.A { background: rgba(92, 194, 141, 0.2); color: var(--green); }
.rc-grade-badge.B { background: rgba(95, 168, 216, 0.2); color: var(--accent); }
.rc-grade-badge.C { background: rgba(240, 184, 110, 0.2); color: var(--amber); }
.rc-grade-badge.D, .rc-grade-badge.F { background: rgba(224, 123, 107, 0.2); color: var(--red); }
.rc-pct { color: var(--ink-dim); margin-top: 6px; font-size: 14px; }

.rc-sections {
  margin: 24px 0; display: flex; flex-direction: column; gap: 8px;
}
.rc-section-row {
  display: flex; align-items: center; gap: 12px;
  padding: 10px 14px; background: var(--bg-3); border-radius: 8px;
  font-size: 14px;
}
.rcs-roman { font-family: Georgia, serif; font-weight: 600; color: var(--accent); min-width: 28px; }
.rcs-title { flex: 1; }
.rcs-score { font-weight: 600; }

.rc-actions { display: flex; gap: 12px; margin-top: 20px; }
.rc-actions button { flex: 1; }

/* Toast */
.toast {
  position: fixed; top: 80px; left: 50%; transform: translateX(-50%) translateY(-120px);
  background: rgba(28, 37, 51, 0.95);
  backdrop-filter: blur(10px);
  padding: 12px 22px; border-radius: 12px;
  border: 1px solid var(--bg-3);
  font-size: 14px; z-index: 1000;
  transition: transform 300ms; pointer-events: none;
}
.toast.show { transform: translateX(-50%) translateY(0); }
.toast.success { border-color: var(--green); color: #b8e8cf; }
.toast.fail { border-color: var(--red); color: #f0c0b8; }

/* Results — wrong-answer review */
.rc-review { margin: 18px 0 4px; border: 1px solid var(--bg-3); border-radius: 12px; background: var(--bg-2); overflow: hidden; }
.rc-review summary { cursor: pointer; padding: 12px 16px; font-weight: 600; color: var(--amber); list-style: none; }
.rc-review summary::-webkit-details-marker { display: none; }
.rc-review summary::before { content: '▸ '; }
.rc-review[open] summary::before { content: '▾ '; }
.rc-miss-list { padding: 4px 16px 14px; }
.rc-miss-row { padding: 10px 0; border-top: 1px solid var(--bg-3); }
.rc-miss-row:first-child { border-top: none; }
.rc-miss-q { font-size: 14px; color: var(--ink); line-height: 1.5; }
.rc-miss-q b { color: var(--ink-dim); font-size: 12px; margin-right: 4px; }
.rc-miss-a { font-size: 14px; color: var(--green); font-weight: 600; margin-top: 4px; }
.rc-allright { margin: 18px 0 4px; padding: 14px 16px; border-radius: 12px; background: var(--green-soft); color: var(--green); font-weight: 600; text-align: center; }
.rc-practice-btn { margin-top: 14px; }
.rc-practice-tag { display: inline-block; margin-top: 8px; padding: 4px 12px; border-radius: 999px; background: rgba(240,184,110,0.15); color: var(--amber); font-size: 13px; font-weight: 600; }

@media (max-width: 640px) {
  .quiz-grid { grid-template-columns: 1fr; }
  .home-hero { padding: 24px 20px 12px; }
  .home-hero h1 { font-size: 28px; }
  .section-body { padding: 16px 18px; }
  .q-card { padding: 16px; }
  .wb-grid { grid-template-columns: repeat(2, 1fr); }
  .sr-buttons { flex-direction: column; }
  .rc-score { font-size: 56px; }
}