:root {
  --bg: #f5f7fb; --fg: #1a2233; --card: #fff; --line: #d9dfeb; --accent: #1d4ed8;
  --ok: #15803d; --ng: #b91c1c; --muted: #5b667a;
}
@media (prefers-color-scheme: dark) {
  :root { --bg: #0f1420; --fg: #e6eaf2; --card: #19202f; --line: #2b3550; --accent: #6b9bff; --ok: #4ade80; --ng: #f87171; --muted: #94a0b8; }
}
* { box-sizing: border-box; }
body { margin: 0; background: var(--bg); color: var(--fg); font: 16px/1.6 system-ui, "Hiragino Sans", "Noto Sans JP", sans-serif; }
main { max-width: 640px; margin: 0 auto; padding: 16px 16px 88px; }
h1 { font-size: 1.4rem; margin: 8px 0 12px; }
h2 { font-size: 1.05rem; margin: 16px 0 8px; }
a { color: var(--accent); }
.card { background: var(--card); border: 1px solid var(--line); border-radius: 12px; padding: 14px; margin: 10px 0; }
.card.link { display: block; text-decoration: none; color: inherit; }
.card.link .meta { display: block; }
.meta { color: var(--muted); font-size: .85rem; }
.q { font-weight: 600; margin-top: 0; }
.grid { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; margin: 10px 0; }
.tile { display: flex; flex-direction: column; gap: 2px; padding: 14px; border-radius: 12px; border: 1px solid var(--line); background: var(--card); color: var(--fg); text-decoration: none; font: inherit; text-align: left; }
.tile span { color: var(--muted); font-size: .85rem; }
button, .btn { font: inherit; padding: 10px 14px; border-radius: 10px; border: 1px solid var(--line); background: var(--card); color: var(--fg); cursor: pointer; text-decoration: none; display: inline-block; }
button:disabled { opacity: .5; cursor: default; }
.primary { background: var(--accent); border-color: var(--accent); color: #fff; }
.danger { color: var(--ng); }
.choice { display: block; width: 100%; text-align: left; margin: 8px 0; }
.choice.right { border-color: var(--ok); background: color-mix(in srgb, var(--ok) 18%, var(--card)); }
.choice.wrong { border-color: var(--ng); background: color-mix(in srgb, var(--ng) 18%, var(--card)); }
.okbox { border-color: var(--ok); } .ngbox { border-color: var(--ng); }
.form label { display: block; margin-bottom: 12px; }
.form select, .form input[type=date], textarea { display: block; width: 100%; margin-top: 4px; padding: 10px; font: inherit; border-radius: 8px; border: 1px solid var(--line); background: var(--bg); color: var(--fg); }
.check { display: flex !important; gap: 8px; align-items: flex-start; margin: 8px 0; }
.row { display: flex; gap: 10px; } .row button { flex: 1; }
.hidden { display: none; }
.flash { min-height: 160px; cursor: pointer; }
.score { font-size: 2.4rem; font-weight: 700; margin: 0; }
.bar { display: grid; grid-template-columns: 1fr; gap: 2px; margin: 8px 0; font-size: .9rem; }
.bar div { height: 8px; background: var(--line); border-radius: 4px; overflow: hidden; }
.bar i { display: block; height: 100%; background: var(--accent); }
.bar em { font-style: normal; color: var(--muted); font-size: .8rem; }
nav { position: fixed; bottom: 0; left: 0; right: 0; display: flex; background: var(--card); border-top: 1px solid var(--line); padding-bottom: env(safe-area-inset-bottom); }
nav a { flex: 1; text-align: center; padding: 12px 0; text-decoration: none; color: var(--muted); font-size: .85rem; }
nav a.on { color: var(--accent); font-weight: 700; }
.q, .choice, .flash p { white-space: pre-wrap; overflow-wrap: anywhere; }
.q { font-weight: 500; }
.choice { line-height: 1.5; }
.wide { display: block; width: 100%; margin: 10px 0; }
.mockbar { position: sticky; top: 0; z-index: 2; display: flex; align-items: center; justify-content: space-between; gap: 8px; padding: 8px 0; background: var(--bg); }
.mockbar b.warn { color: var(--ng); }
.choice.picked { border-color: var(--accent); background: color-mix(in srgb, var(--accent) 15%, var(--card)); }
.cells { display: grid; grid-template-columns: repeat(10, 1fr); gap: 4px; margin: 12px 0 4px; }
.cell { padding: 6px 0; font-size: .75rem; text-align: center; }
.cell.done { background: color-mix(in srgb, var(--accent) 18%, var(--card)); }
.cell.cur { outline: 2px solid var(--accent); }
details.card summary { cursor: pointer; font-weight: 600; }
nav a { font-size: .8rem; }
.quote { border-left: 3px solid var(--line); padding-left: 8px; }