:root {
  color-scheme: light dark;
  --bg: #f3efe6;
  --elev: #fffdf8;
  --ink: #1d1916;
  --muted: #5f574e;
  --line: #e3dacd;
  --accent: #1f4d3a;
  --accent-ink: #f7fbf8;
  --soft: #e7f0ea;
  --ok: #1f4d3a;
  --ok-bg: #e7f0ea;
  --bad: #8d2f2f;
  --bad-bg: #fdeeee;
  --warn: #8a5a12;
  --warn-bg: #fff3dc;
  --code: #efe8dc;
  --shadow: 0 10px 30px rgba(70, 48, 20, 0.06);
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #161310;
    --elev: #221e1a;
    --ink: #f6f1e8;
    --muted: #b7aea2;
    --line: #3c352e;
    --accent: #9ed4b8;
    --accent-ink: #14241c;
    --soft: #1b332c;
    --ok: #9ed4b8;
    --ok-bg: #1b332c;
    --bad: #f0b4b4;
    --bad-bg: #3c2222;
    --warn: #efd09a;
    --warn-bg: #342816;
    --code: #2c261f;
    --shadow: none;
  }
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: "Avenir Next", "PingFang SC", "Hiragino Sans GB", "Noto Sans SC", sans-serif;
  line-height: 1.55;
}

.wrap {
  width: min(48rem, calc(100% - 2rem));
  margin: 0 auto;
  padding: 2rem 0 4rem;
}

.page-head h1,
.quiz-title {
  margin: 0.15rem 0 0.4rem;
  font-size: 2rem;
  line-height: 1.2;
  font-weight: 650;
}

.eyebrow {
  margin: 0;
  color: var(--accent);
  font-size: 0.82rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.lede,
.meta,
.note,
.status,
.intro {
  color: var(--muted);
}

.lede { margin-top: 0; }

.group-card,
.question,
.banner {
  background: var(--elev);
  border: 1px solid var(--line);
  border-radius: 16px;
  box-shadow: var(--shadow);
}

.group-card {
  padding: 1.1rem 1.2rem 1.2rem;
  margin-bottom: 0.9rem;
}

.group-card h2 {
  margin: 0;
  font-size: 1.15rem;
  line-height: 1.35;
}

.meta,
.note { margin: 0.4rem 0 0; }

.actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-top: 0.9rem;
}

.button,
button {
  font: inherit;
  color: var(--accent-ink);
  background: var(--accent);
  border: 0;
  border-radius: 999px;
  padding: 0.45rem 0.9rem;
  text-decoration: none;
  cursor: pointer;
}

.button.secondary,
button.secondary {
  color: var(--ink);
  background: transparent;
  border: 1px solid var(--line);
}

button:disabled { opacity: 0.45; cursor: not-allowed; }

.sticky {
  position: sticky;
  top: 0;
  z-index: 2;
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  align-items: center;
  margin: 0 -1rem 1rem;
  padding: 0.75rem 1rem;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}

.sticky p { margin: 0; }
.sticky strong { font-size: 1.05rem; }

.intro,
.banner { padding: 0.9rem 1rem; margin: 0 0 1rem; }

.question {
  padding: 1.15rem 1.2rem 1.2rem;
  margin-bottom: 1rem;
}

.question header {
  display: flex;
  justify-content: space-between;
  gap: 0.8rem;
  align-items: baseline;
  margin-bottom: 0.55rem;
}

.q-label {
  margin: 0;
  font-size: 0.95rem;
  font-weight: 700;
}

.pill {
  color: var(--muted);
  font-size: 0.85rem;
}

.scenario {
  margin: 0 0 0.45rem;
  color: var(--accent);
  font-size: 0.92rem;
}

.stem {
  font-family: "Iowan Old Style", Georgia, "Songti SC", serif;
  font-size: 1.22rem;
  line-height: 1.65;
}

.stem p { margin: 0 0 0.7rem; }
.stem p:last-child { margin-bottom: 0; }

.options { display: grid; gap: 0.45rem; margin-top: 0.9rem; }

.option {
  display: grid;
  grid-template-columns: auto auto 1fr;
  gap: 0.55rem;
  align-items: start;
  padding: 0.65rem 0.75rem;
  border: 1px solid var(--line);
  border-radius: 12px;
  cursor: pointer;
}

.option:has(input:checked) {
  border-color: var(--accent);
  background: var(--soft);
}

.option input { margin-top: 0.3rem; }

.letter {
  font-weight: 700;
  min-width: 1rem;
}

.opt-text { font-size: 1.02rem; line-height: 1.5; }

.dontknow {
  margin-top: 0.7rem;
  color: var(--ink);
  background: transparent;
  border: 1px solid var(--line);
}

.dontknow[aria-pressed="true"] {
  color: var(--warn);
  background: var(--warn-bg);
  border-color: transparent;
}

details { margin-top: 0.8rem; }
summary { cursor: pointer; color: var(--muted); }
details p { margin: 0.4rem 0 0; }

.question.is-wrong { background: var(--bad-bg); }
.question.is-dontknow,
.question.is-unscored { background: var(--warn-bg); }
.question.is-correct { background: var(--ok-bg); }

.badge {
  font-size: 0.85rem;
  font-weight: 700;
}

.is-wrong .badge { color: var(--bad); }
.is-dontknow .badge,
.is-unscored .badge { color: var(--warn); }
.is-correct .badge { color: var(--ok); }

.answer-line { margin: 0.35rem 0; }
.explain-block { margin-top: 0.8rem; }

.ai {
  margin-top: 0.9rem;
  padding-top: 0.8rem;
  border-top: 1px solid var(--line);
}

.ai-output {
  margin-top: 0.7rem;
}

.ai-output .user {
  margin: 0.8rem 0 0.3rem;
  color: var(--muted);
}

.follow {
  display: flex;
  gap: 0.5rem;
  margin-top: 0.7rem;
}

.follow textarea {
  flex: 1;
  min-height: 2.6rem;
  font: inherit;
  color: var(--ink);
  background: var(--bg);
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 0.45rem 0.6rem;
  resize: vertical;
}

code {
  font-family: "SF Mono", ui-monospace, Menlo, Consolas, monospace;
  font-size: 0.88em;
  background: var(--code);
  padding: 0.08em 0.35em;
  border-radius: 4px;
}

pre code {
  display: block;
  padding: 0.8rem 1rem;
  overflow-x: auto;
}

a { color: var(--accent); }

blockquote {
  margin: 0.4rem 0;
  padding-left: 0.8rem;
  border-left: 3px solid var(--line);
  color: var(--muted);
}

.login form { display: grid; gap: 0.7rem; max-width: 22rem; }
.login input {
  font: inherit;
  font-size: 1rem;
  color: var(--ink);
  background: var(--bg);
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 0.55rem 0.7rem;
}

@media (max-width: 600px) {
  .wrap { width: calc(100% - 1.5rem); padding: 1rem 0 3rem; }
  .page-head h1, .quiz-title { font-size: 1.5rem; }
  .sticky { margin: 0 -0.75rem 0.8rem; padding: 0.6rem 0.75rem; }
  .question, .group-card { padding: 0.9rem 0.85rem 1rem; border-radius: 12px; }
  .stem { font-size: 1.08rem; line-height: 1.6; }
  .option { padding: 0.75rem 0.65rem; }
  .opt-text { font-size: 1rem; }
  .follow { flex-direction: column; }
  .follow textarea { font-size: 1rem; }
  pre code { font-size: 0.8rem; }
}

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}