:root {
  --bg: #f7f7fb; --card: #ffffff; --text: #0b0b0f; --muted: #63636f; --line: #e6e6ef;
  --brand: #4f46e5; --brand-ink: #ffffff; --good: #187a42; --bad: #c0302c; --warn: #855400;
  --good-bg: #e7f6ec; --bad-bg: #fdeaea; --warn-bg: #fff6e0; --accent-bg: #eef0ff;
  --chip-new: #cfd5df; --chip-weak: #f0a3a3; --chip-learning: #f6d58a; --chip-strong: #8fd3a8;
  --radius: 12px;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0a0a0d; --card: #17171d; --text: #f5f5f7; --muted: #9a9aa5; --line: #27272f;
    --brand: #818cf8; --brand-ink: #0a0a0d; --good: #55c783; --bad: #ff7b7b; --warn: #e9b44c;
    --good-bg: #17301f; --bad-bg: #351b1b; --warn-bg: #352c14; --accent-bg: rgba(129,140,248,.14);
    --chip-new: #3a4256; --chip-weak: #7c3a3a; --chip-learning: #7c6428; --chip-strong: #2f6a46;
  }
}
* { box-sizing: border-box; }
body { margin: 0; background: var(--bg); color: var(--text); font: 16px/1.5 "Inter", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif; }
a { color: var(--brand); }
h1 { font-size: 1.6rem; margin: .4rem 0 .6rem; }
h2 { font-size: 1.2rem; margin: 1.4rem 0 .6rem; }
h3 { font-size: 1.02rem; margin: 0; }
.qtext { font-size: 1.1rem; line-height: 1.45; }

.topbar { position: sticky; top: 0; z-index: 5; display: flex; align-items: center; gap: 12px; padding: 8px 16px; background: var(--card); border-bottom: 1px solid var(--line); overflow-x: auto; }
.back { color: var(--muted); text-decoration: none; white-space: nowrap; font-size: .88rem; }
.back:hover { color: var(--brand); }
a:focus-visible, button:focus-visible { outline: 2px solid var(--brand); outline-offset: 2px; }
.brand { font-family: "Space Grotesk", inherit; font-weight: 700; letter-spacing: .3px; white-space: nowrap; }
.nav { display: flex; gap: 4px; flex: 1; }
.nav a { padding: 6px 10px; border-radius: 8px; text-decoration: none; color: var(--muted); white-space: nowrap; }
.nav a.active { background: var(--accent-bg); color: var(--brand); font-weight: 600; }
.lang { border: 1px solid var(--line); background: transparent; color: var(--text); border-radius: 8px; padding: 6px 10px; cursor: pointer; white-space: nowrap; }

main { max-width: 960px; margin: 0 auto; padding: 16px; }
.page > * + * { margin-top: 12px; }
.grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); gap: 12px; }
.card { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 14px; }
.card > * + * { margin-top: 8px; }
.card.link { display: block; text-decoration: none; color: inherit; }
.card.accent { background: var(--accent-bg); }
.card.warn { background: var(--warn-bg); }
.card.error { background: var(--bad-bg); }
.card.today { outline: 2px solid var(--brand); }
.okbox { background: var(--good-bg); }
.badbox { background: var(--bad-bg); }
.expl { background: var(--accent-bg); }
.ok { color: var(--good); font-weight: 600; }
.bad { color: var(--bad); font-weight: 600; }
.muted { color: var(--muted); }
.small { font-size: .88rem; }
.big { font-size: 2rem; font-weight: 800; }

.row { display: flex; align-items: center; justify-content: space-between; gap: 8px; flex-wrap: wrap; }
.row.gap { justify-content: flex-start; }
.stats { display: grid; grid-template-columns: repeat(auto-fit, minmax(130px, 1fr)); gap: 10px; }
.stat { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 12px; }
.stat .v { font-size: 1.5rem; font-weight: 800; }
.stat .l { color: var(--muted); font-size: .85rem; }
.stat .s { color: var(--muted); font-size: .75rem; }

.bar { height: 8px; border-radius: 99px; background: var(--line); overflow: hidden; }
.bar > span { display: block; height: 100%; background: var(--brand); border-radius: 99px; }
.bar.good > span { background: var(--good); }
.bar.bad > span { background: var(--bad); }
.lbl { font-size: .8rem; color: var(--muted); margin-bottom: 2px; }

.badge { display: inline-block; font-size: .72rem; padding: 2px 8px; border-radius: 99px; background: var(--accent-bg); color: var(--brand); white-space: nowrap; }
.badge.k1 { background: var(--good-bg); color: var(--good); }
.badge.k3 { background: var(--warn-bg); color: var(--warn); }
.chips { display: flex; flex-wrap: wrap; gap: 4px; }
.chip { display: inline-block; font-size: .72rem; padding: 2px 7px; border-radius: 6px; text-decoration: none; color: var(--text); border: 1px solid transparent; }
.chip.new { background: var(--chip-new); }
.chip.weak { background: var(--chip-weak); }
.chip.learning { background: var(--chip-learning); }
.chip.strong { background: var(--chip-strong); }
.chip.none { background: transparent; border-color: var(--line); color: var(--muted); }
.legend { margin-top: 8px; }

.btn { display: inline-block; border: 1px solid var(--line); background: var(--card); color: var(--text); border-radius: 10px; padding: 8px 14px; cursor: pointer; font: inherit; text-decoration: none; }
.btn:hover:not(:disabled) { border-color: var(--brand); }
.btn:disabled { opacity: .5; cursor: not-allowed; }
.btn.primary { background: var(--brand); color: var(--brand-ink); border-color: var(--brand); }
.btn.good { background: #187a42; color: #fff; border-color: #187a42; }
.btn.danger { background: #b42318; color: #fff; border-color: #b42318; }
.btn.small { padding: 4px 10px; font-size: .85rem; }

label { display: block; font-size: .9rem; color: var(--muted); }
label.inline { display: flex; gap: 8px; align-items: center; color: var(--text); }
select, input[type=date], input[type=number], input[type=email], input[type=password], textarea { display: block; width: 100%; margin-top: 4px; padding: 8px 10px; border: 1px solid var(--line); border-radius: 8px; background: var(--card); color: var(--text); font: inherit; }
label.inline input { width: auto; margin: 0; }
textarea { resize: vertical; }

.qbody > * + * { margin-top: 8px; }
.opt { display: block; width: 100%; text-align: left; padding: 10px 12px; border: 1px solid var(--line); border-radius: 10px; background: var(--card); color: var(--text); font: inherit; cursor: pointer; margin-top: 8px; }
.opt:hover:not(:disabled) { border-color: var(--brand); }
.opt.picked { border-color: var(--brand); background: var(--accent-bg); }
.opt.right { border-color: var(--good); background: var(--good-bg); }
.opt.wrong { border-color: var(--bad); background: var(--bad-bg); }
.opt:disabled { cursor: default; color: var(--text); }

.sticky { position: sticky; top: 52px; background: var(--bg); padding: 8px 0; z-index: 4; }
.timer { font-variant-numeric: tabular-nums; font-weight: 700; font-size: 1.1rem; }
.timer.low { color: var(--bad); }
.palette { display: flex; flex-wrap: wrap; gap: 6px; }
.pal { width: 36px; height: 36px; border-radius: 8px; border: 1px solid var(--line); background: var(--card); color: var(--text); cursor: pointer; }
.pal.done { background: var(--accent-bg); }
.pal.flag { border-color: var(--warn); box-shadow: inset 0 0 0 2px var(--warn); }
.pal.cur { outline: 2px solid var(--brand); }
details.rev summary { cursor: pointer; font-weight: 600; }
details.rev > * + * { margin-top: 6px; }
.flash { text-align: center; }
.flash .row { justify-content: center; }

@media (max-width: 520px) {
  main { padding: 10px; }
  h1 { font-size: 1.35rem; }
  .topbar { padding: 6px 10px; }
}

.conf .btn { flex: 1; min-width: 90px; }
.conf .btn.conf-sure:hover { border-color: var(--good); }
.conf .btn.conf-guess:hover { border-color: var(--warn); }
.bad.small { font-weight: 600; }
details > summary { cursor: pointer; }
details > summary:focus-visible { outline: 2px solid var(--brand); outline-offset: 2px; }
.sr-only { position: absolute; width: 1px; height: 1px; margin: -1px; padding: 0; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; border: 0; }
.qtext:focus { outline: none; }
.h3 { font-size: 1.02rem; margin: 0; }