:root {
  --bg: #0f1419;
  --bg-elev: #1a222d;
  --bg-card: #1e2836;
  --border: #2d3a4d;
  --text: #e8eef6;
  --muted: #8b9bb0;
  --primary: #4f8cff;
  --primary-hover: #6ba0ff;
  --accent: #34d399;
  --danger: #f87171;
  --warn: #fbbf24;
  --flag: #fbbf24;
  --radius: 14px;
  --shadow: 0 8px 28px rgba(0, 0, 0, 0.35);
  --font: "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei",
    "Noto Sans SC", "Hiragino Kaku Gothic ProN", "Yu Gothic", Meiryo, sans-serif;
  --jp: "Hiragino Kaku Gothic ProN", "Hiragino Sans", "Noto Sans JP",
    "Yu Gothic", Meiryo, "MS PGothic", sans-serif;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: var(--font);
  background:
    radial-gradient(1200px 600px at 10% -10%, #1a3a6a55, transparent),
    radial-gradient(900px 500px at 100% 0%, #0d4a3a33, transparent),
    var(--bg);
  color: var(--text);
  line-height: 1.55;
}

#app {
  max-width: 720px;
  margin: 0 auto;
  padding: 20px 16px 48px;
}

.view {
  display: none;
  animation: fadeIn 0.28s ease;
}
.view.active {
  display: block;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(6px); }
  to { opacity: 1; transform: none; }
}

.hero {
  text-align: center;
  margin: 12px 0 24px;
}
.hero.compact {
  margin-bottom: 16px;
}
.hero-badge {
  display: inline-block;
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--accent);
  background: rgba(52, 211, 153, 0.12);
  border: 1px solid rgba(52, 211, 153, 0.35);
  padding: 4px 10px;
  border-radius: 999px;
  margin-bottom: 10px;
}
.hero h1 {
  margin: 0 0 8px;
  font-size: clamp(1.55rem, 4.5vw, 1.9rem);
  font-weight: 700;
}
.hero-sub {
  margin: 0;
  color: var(--muted);
  font-size: 0.95rem;
}

.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px 16px;
  margin-bottom: 16px;
  box-shadow: var(--shadow);
}
.card-title {
  margin: 0 0 14px;
  font-size: 1rem;
  font-weight: 600;
  color: var(--muted);
}
.card-title.sm {
  font-size: 0.9rem;
  margin-bottom: 10px;
}

.level-grid {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 8px;
}
.level-btn {
  appearance: none;
  border: 1px solid var(--border);
  background: var(--bg-elev);
  color: var(--text);
  border-radius: 12px;
  padding: 12px 4px;
  cursor: pointer;
  transition: border-color 0.15s, background 0.15s, transform 0.1s;
}
.level-btn:hover {
  border-color: var(--primary);
}
.level-btn.selected {
  border-color: var(--primary);
  background: rgba(79, 140, 255, 0.18);
  box-shadow: inset 0 0 0 1px var(--primary);
}
.level-btn .lv {
  display: block;
  font-weight: 700;
  font-size: 1.05rem;
}
.level-btn .lv-desc {
  display: block;
  font-size: 0.7rem;
  color: var(--muted);
  margin-top: 2px;
}

.mode-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.mode-btn {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  text-align: left;
  appearance: none;
  border: 1px solid var(--border);
  background: var(--bg-elev);
  color: var(--text);
  border-radius: 12px;
  padding: 12px 14px;
  cursor: pointer;
  transition: border-color 0.15s, background 0.15s;
}
.mode-btn:hover {
  border-color: var(--primary);
}
.mode-btn.selected {
  border-color: var(--primary);
  background: rgba(79, 140, 255, 0.15);
}
.mode-icon {
  font-size: 1.25rem;
  line-height: 1.4;
}
.mode-text strong {
  display: block;
  font-size: 0.98rem;
}
.mode-text small {
  color: var(--muted);
  font-size: 0.82rem;
}

.section-pick {
  display: flex;
  flex-wrap: wrap;
  gap: 12px 18px;
  margin-top: 12px;
  padding-top: 12px;
  border-top: 1px dashed var(--border);
  font-size: 0.95rem;
}
.section-pick.hidden {
  display: none;
}
.section-pick label {
  cursor: pointer;
  color: var(--text);
  display: flex;
  align-items: center;
  gap: 6px;
}

.btn {
  appearance: none;
  border: none;
  border-radius: 10px;
  padding: 10px 16px;
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  font-family: inherit;
  transition: background 0.15s, opacity 0.15s, transform 0.08s;
}
.btn:active {
  transform: scale(0.98);
}
.btn:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}
.btn.primary {
  background: var(--primary);
  color: #fff;
}
.btn.primary:hover:not(:disabled) {
  background: var(--primary-hover);
}
.btn.secondary {
  background: var(--bg-elev);
  color: var(--text);
  border: 1px solid var(--border);
}
.btn.accent {
  background: var(--accent);
  color: #0b1a12;
}
.btn.ghost {
  background: transparent;
  color: var(--muted);
  border: 1px solid transparent;
}
.btn.ghost:hover {
  color: var(--text);
  border-color: var(--border);
}
.btn.sm {
  padding: 6px 10px;
  font-size: 0.82rem;
}
.btn-lg {
  width: 100%;
  padding: 14px;
  font-size: 1.05rem;
  margin-top: 4px;
}

.footnote {
  text-align: center;
  color: var(--muted);
  font-size: 0.78rem;
  margin: 20px 0 0;
}

/* Exam */
.exam-top {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 10px;
}
.exam-meta {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 2px;
  min-width: 0;
}
#exam-label {
  font-weight: 600;
  font-size: 0.92rem;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.timer {
  font-variant-numeric: tabular-nums;
  color: var(--warn);
  font-size: 0.85rem;
  font-weight: 700;
}
.timer.hidden {
  display: none;
}
.timer.urgent {
  color: var(--danger);
  animation: pulse 1s infinite;
}
@keyframes pulse {
  50% { opacity: 0.55; }
}
.progress-text {
  font-size: 0.85rem;
  color: var(--muted);
  font-variant-numeric: tabular-nums;
}
.progress-bar {
  height: 5px;
  background: var(--border);
  border-radius: 999px;
  overflow: hidden;
  margin-bottom: 14px;
}
.progress-fill {
  height: 100%;
  width: 0%;
  background: linear-gradient(90deg, var(--primary), var(--accent));
  transition: width 0.25s ease;
}

.exam-card .q-meta {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 12px;
}
.tag {
  font-size: 0.75rem;
  font-weight: 600;
  padding: 3px 8px;
  border-radius: 6px;
  background: rgba(79, 140, 255, 0.15);
  color: var(--primary-hover);
}
.tag.grammar {
  background: rgba(52, 211, 153, 0.15);
  color: var(--accent);
}
.tag.reading {
  background: rgba(251, 191, 36, 0.15);
  color: var(--warn);
}

.q-stem {
  font-family: var(--jp);
  font-size: 1.12rem;
  line-height: 1.75;
  white-space: pre-wrap;
  margin-bottom: 18px;
  letter-spacing: 0.02em;
}

.q-options {
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.opt-btn {
  appearance: none;
  text-align: left;
  border: 1px solid var(--border);
  background: var(--bg-elev);
  color: var(--text);
  border-radius: 12px;
  padding: 12px 14px;
  cursor: pointer;
  font-family: var(--jp);
  font-size: 1rem;
  line-height: 1.5;
  display: flex;
  gap: 10px;
  align-items: flex-start;
  transition: border-color 0.15s, background 0.15s;
}
.opt-btn:hover {
  border-color: var(--primary);
}
.opt-btn.selected {
  border-color: var(--primary);
  background: rgba(79, 140, 255, 0.18);
}
.opt-letter {
  flex-shrink: 0;
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.08);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 0.8rem;
  font-weight: 700;
  font-family: var(--font);
  margin-top: 1px;
}
.opt-btn.selected .opt-letter {
  background: var(--primary);
  color: #fff;
}

.nav-row {
  display: flex;
  gap: 10px;
  margin: 14px 0;
  flex-wrap: wrap;
}
.nav-row .btn {
  flex: 1;
  min-width: 100px;
}
.nav-row .hidden {
  display: none;
}

.q-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}
.q-nav button {
  width: 36px;
  height: 36px;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--bg-elev);
  color: var(--text);
  font-size: 0.82rem;
  font-weight: 600;
  cursor: pointer;
  font-variant-numeric: tabular-nums;
}
.q-nav button.answered {
  background: rgba(79, 140, 255, 0.25);
  border-color: var(--primary);
}
.q-nav button.flagged {
  box-shadow: inset 0 -3px 0 var(--flag);
}
.q-nav button.current {
  outline: 2px solid var(--accent);
  outline-offset: 1px;
}

/* Result */
.score-card {
  text-align: center;
}
.score-ring {
  width: 120px;
  height: 120px;
  margin: 8px auto 16px;
  border-radius: 50%;
  display: grid;
  place-items: center;
  background: conic-gradient(var(--accent) 0%, var(--border) 0%);
  position: relative;
}
.score-ring::before {
  content: "";
  position: absolute;
  inset: 10px;
  border-radius: 50%;
  background: var(--bg-card);
}
#score-pct {
  position: relative;
  font-size: 1.6rem;
  font-weight: 800;
  font-variant-numeric: tabular-nums;
}
.score-stats {
  display: flex;
  justify-content: center;
  gap: 28px;
  margin-bottom: 8px;
}
.score-stats strong {
  display: block;
  font-size: 1.35rem;
}
.score-stats span {
  font-size: 0.78rem;
  color: var(--muted);
}
.estimate {
  margin: 12px 0 0;
  padding: 10px 12px;
  background: rgba(52, 211, 153, 0.1);
  border: 1px solid rgba(52, 211, 153, 0.3);
  border-radius: 10px;
  color: var(--accent);
  font-size: 0.92rem;
}
.estimate.hidden {
  display: none;
}

.review-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
}
.review-item {
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 12px;
  background: var(--bg-elev);
}
.review-item.ok {
  border-color: rgba(52, 211, 153, 0.45);
}
.review-item.bad {
  border-color: rgba(248, 113, 113, 0.45);
}
.review-head {
  display: flex;
  justify-content: space-between;
  gap: 8px;
  margin-bottom: 8px;
  font-size: 0.82rem;
  color: var(--muted);
}
.review-stem {
  font-family: var(--jp);
  font-size: 0.98rem;
  white-space: pre-wrap;
  margin-bottom: 8px;
  line-height: 1.65;
}
.review-ans {
  font-size: 0.88rem;
  margin-bottom: 4px;
}
.review-ans .good {
  color: var(--accent);
}
.review-ans .bad {
  color: var(--danger);
}
.review-explain {
  font-size: 0.88rem;
  color: var(--muted);
  border-top: 1px dashed var(--border);
  padding-top: 8px;
  margin-top: 6px;
}

.toast {
  position: fixed;
  left: 50%;
  bottom: 24px;
  transform: translateX(-50%);
  background: #243044;
  border: 1px solid var(--border);
  color: var(--text);
  padding: 10px 16px;
  border-radius: 10px;
  font-size: 0.9rem;
  z-index: 50;
  box-shadow: var(--shadow);
}
.toast.hidden {
  display: none;
}

#btn-flag[aria-pressed="true"] {
  color: var(--flag);
}

@media (max-width: 480px) {
  .level-grid {
    grid-template-columns: repeat(5, 1fr);
    gap: 6px;
  }
  .level-btn {
    padding: 10px 2px;
  }
  .level-btn .lv-desc {
    font-size: 0.62rem;
  }
  .q-stem {
    font-size: 1.05rem;
  }
}