:root {
  color-scheme: light;
  --ink: #1e293b;
  --muted: #64748b;
  --paper: #f8fafc;
  --card: #ffffff;
  --line: #dbe4ee;
  --navy: #183b5b;
  --blue: #2563eb;
  --blue-soft: #eaf2ff;
  --green: #097969;
  --green-soft: #e8f7f3;
  --red: #bd3c4a;
  --red-soft: #fff0f1;
  --amber: #b45309;
  font-family: "Noto Sans JP", "Hiragino Sans", "Yu Gothic UI", sans-serif;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  min-width: 320px;
  color: var(--ink);
  background:
    radial-gradient(circle at top right, #dcecff 0, transparent 28rem),
    var(--paper);
}

button, select { font: inherit; }
button { cursor: pointer; }

.site-header {
  width: min(1120px, calc(100% - 2rem));
  min-height: 86px;
  margin: auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: .7rem;
  color: var(--navy);
  text-decoration: none;
  font-size: .76rem;
  line-height: 1.35;
  letter-spacing: .05em;
}
.brand strong { font-size: 1.15rem; letter-spacing: .02em; }
.brand-mark {
  display: grid;
  width: 2.3rem;
  height: 2.3rem;
  place-items: center;
  color: #fff;
  border-radius: 50%;
  background: var(--navy);
  font: 800 1.2rem Georgia, serif;
}
.header-note { margin: 0; color: var(--muted); font-size: .86rem; }

.app { width: min(1120px, calc(100% - 2rem)); margin: 1.5rem auto 4rem; }

.card, .loading-card {
  padding: clamp(1.35rem, 4vw, 3rem);
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 1.25rem;
  box-shadow: 0 12px 30px rgb(30 41 59 / 6%);
}
.loading-card { display: grid; min-height: 260px; place-content: center; justify-items: center; gap: .75rem; color: var(--muted); }
.spinner { width: 2rem; height: 2rem; border: 3px solid var(--blue-soft); border-top-color: var(--blue); border-radius: 50%; animation: spin .9s linear infinite; }
@keyframes spin { to { transform: rotate(360deg); } }

.eyebrow, .source-label { margin: 0; color: var(--blue); font-size: .78rem; font-weight: 800; letter-spacing: .08em; }
h1, h2, p { overflow-wrap: anywhere; }
.setup-card { max-width: 720px; margin: 6vh auto; }
.setup-card h1 { margin: .6rem 0 1rem; color: var(--navy); font-size: clamp(2rem, 6vw, 3.35rem); line-height: 1.18; letter-spacing: -.05em; }
.lead { max-width: 37rem; color: var(--muted); line-height: 1.9; }
.setup-actions { display: grid; grid-template-columns: minmax(0, 1fr) auto; gap: 1rem; align-items: end; margin-top: 2rem; }
.field-label { display: grid; gap: .45rem; color: var(--navy); font-size: .85rem; font-weight: 700; }
select { width: 100%; padding: .82rem 1rem; color: var(--ink); background: #fff; border: 1px solid #bfcede; border-radius: .65rem; }

.button {
  min-height: 2.9rem;
  padding: .7rem 1.15rem;
  color: #fff;
  background: var(--blue);
  border: 1px solid var(--blue);
  border-radius: .7rem;
  font-weight: 800;
  transition: transform .15s ease, background .15s ease;
}
.button:hover { background: #1d4ed8; transform: translateY(-1px); }
.button:focus-visible, .choice:focus-visible, select:focus-visible { outline: 3px solid #93c5fd; outline-offset: 3px; }
.button.secondary { color: var(--navy); background: #fff; border-color: #bdcddd; }
.button.secondary:hover { background: #f1f5f9; }
.button.wide { width: min(100%, 24rem); margin-top: 1.75rem; }

.progress-row { display: flex; align-items: center; justify-content: space-between; gap: 1rem; margin-bottom: 1.5rem; color: var(--muted); font-size: .84rem; }
.progress-track { width: 10rem; height: .45rem; overflow: hidden; background: #e4eaf1; border-radius: 99px; }
.progress-value { height: 100%; background: var(--blue); border-radius: inherit; transition: width .25s ease; }
.lesson-badge { display: inline-flex; padding: .32rem .56rem; color: var(--blue); background: var(--blue-soft); border-radius: 99px; font-size: .79rem; font-weight: 800; }
.question-card h1 { max-width: 43rem; margin: 1rem 0 0; color: var(--navy); font-size: clamp(1.45rem, 3.5vw, 2.35rem); line-height: 1.65; letter-spacing: -.025em; white-space: pre-line; }
.question-action { margin-top: 2.2rem; }
.choice-list { display: grid; gap: .75rem; margin-top: 2rem; }
.choice {
  display: grid;
  grid-template-columns: 2rem 1fr;
  align-items: center;
  gap: .8rem;
  width: 100%;
  padding: 1rem;
  color: var(--ink);
  text-align: left;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: .85rem;
  transition: border-color .15s ease, background .15s ease, transform .15s ease;
}
.choice:hover { background: #f8fbff; border-color: #8fb6eb; transform: translateX(2px); }
.choice-key { display: grid; width: 2rem; height: 2rem; place-items: center; color: var(--blue); background: var(--blue-soft); border-radius: 50%; font-size: .82rem; font-weight: 800; }

.answer-layout { display: grid; grid-template-columns: minmax(0, 1fr) minmax(320px, 1fr); gap: 1rem; align-items: stretch; }
.answer-card h1 { margin: .75rem 0 1.25rem; color: var(--navy); font-size: clamp(1.5rem, 3vw, 2.25rem); }
.result-status { display: inline-flex; align-items: center; gap: .5rem; padding: .45rem .7rem; border-radius: .6rem; font-weight: 800; }
.result-status.correct { color: var(--green); background: var(--green-soft); }
.result-status.incorrect { color: var(--red); background: var(--red-soft); }
.answer-detail { display: grid; gap: .85rem; margin-top: 1.4rem; }
.answer-detail div { padding: .9rem 1rem; background: #f8fafc; border-radius: .65rem; }
.answer-detail dt { color: var(--muted); font-size: .78rem; font-weight: 700; }
.answer-detail dd { margin: .25rem 0 0; font-weight: 800; }
.explanation { margin-top: 1.5rem; color: #334155; line-height: 1.9; white-space: pre-line; }
.source-name { margin: 1.2rem 0 0; color: var(--muted); font-size: .8rem; }
.materials-card { padding: 1rem; min-height: 0; }
.materials-card h2 { margin: .35rem 0 1rem; color: var(--navy); font-size: 1.1rem; }
.materials-card h3 { margin: .35rem 0 1rem; color: var(--navy); font-size: 1rem; }
.transcript-note { margin: -.45rem 0 1rem; color: var(--muted); font-size: .78rem; }
.transcript-content {
  max-height: 52rem;
  margin: 0;
  padding: 1rem;
  overflow: auto;
  color: #334155;
  white-space: pre-wrap;
  background: #f8fafc;
  border: 1px solid var(--line);
  border-radius: .65rem;
  font: .82rem/1.8 "Noto Sans JP", "Hiragino Sans", "Yu Gothic UI", sans-serif;
}
.transcript-highlight {
  padding: .08em .16em;
  color: #713f12;
  background: #fde68a;
  border-radius: .2em;
  box-decoration-break: clone;
  -webkit-box-decoration-break: clone;
}
.materials-images { margin-top: 2rem; padding-top: 1.25rem; border-top: 1px solid var(--line); }
.materials-list { display: grid; gap: .8rem; padding-right: .2rem; }
.material-image { display: block; width: 100%; height: auto; border: 1px solid var(--line); border-radius: .65rem; background: #f1f5f9; }
.material-caption { margin: .45rem 0 0; color: var(--muted); font-size: .75rem; }
.empty-material { padding: 1.5rem; color: var(--muted); background: #f8fafc; border-radius: .6rem; }

.results-card { max-width: 700px; margin: 7vh auto; text-align: center; }
.score { margin: 1rem 0; color: var(--blue); font-size: clamp(3.5rem, 13vw, 6.5rem); font-weight: 900; letter-spacing: -.08em; }
.score span { color: var(--muted); font-size: .35em; letter-spacing: 0; }
.results-card p { color: var(--muted); line-height: 1.8; }
.error-card { max-width: 700px; margin: 10vh auto; border-color: #f3b6be; }
.error-card h1 { color: var(--red); }
.noscript { margin: 2rem; text-align: center; }

@media (max-width: 760px) {
  .site-header { min-height: 70px; }
  .header-note { display: none; }
  .setup-actions, .answer-layout { grid-template-columns: 1fr; }
  .setup-actions .button { width: 100%; }
  .answer-layout { gap: .8rem; }
  .materials-card { max-height: none; }
}