:root {
  --paper: #f6f1e7;
  --sheet: #fffdf8;
  --ink: #1b1a17;
  --ink-soft: #5a554b;
  --line: #d9d1c0;
  --marker: #ffe14d;
  --marker-ink: #1b1a17;
  --accent: #c2410c;
  --on-accent: #ffffff;
  --ok: #1e7f4f;
  --ok-bg: #e3f5ea;
  --bad: #b3261e;
  --bad-bg: #fbe7e5;
  --A1: #1f8a7a;
  --A2: #2f5fd0;
  --B1: #7b45c4;
  --B2: #b0431f;
  --level: var(--A1);
  --on-level: #ffffff;
  --radius-s: 4px;
  --radius-l: 6px;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --paper: #17150f; --sheet: #211e16; --ink: #f1ece0; --ink-soft: #b3ab9a; --line: #3a352a; --accent: #f08a5d; --on-accent: #17150f;
    --marker: #8a7415; --marker-ink: #fff8d6; --ok: #6fd39d; --ok-bg: #173b2a; --bad: #ff8f86; --bad-bg: #45201d;
    --A1: #4cc3b1; --A2: #7c9dff; --B1: #b690f0; --B2: #ee8a64; --on-level: #17150f;
  }
}
:root[data-theme="dark"] {
  --paper: #17150f; --sheet: #211e16; --ink: #f1ece0; --ink-soft: #b3ab9a; --line: #3a352a; --accent: #f08a5d; --on-accent: #17150f;
  --marker: #8a7415; --marker-ink: #fff8d6; --ok: #6fd39d; --ok-bg: #173b2a; --bad: #ff8f86; --bad-bg: #45201d;
  --A1: #4cc3b1; --A2: #7c9dff; --B1: #b690f0; --B2: #ee8a64; --on-level: #17150f;
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0; background: var(--paper); color: var(--ink);
  font: 400 1.1875rem/1.6 "Atkinson Hyperlegible", system-ui, sans-serif;
}
main, .masthead-inner, footer { max-width: 44rem; margin: 0 auto; padding: 0 16px; }
h1, h2, h3, .brand { font-family: "Newsreader", Georgia, serif; font-weight: 600; }
.tab { font-family: "Atkinson Hyperlegible", system-ui, sans-serif; }
a { color: var(--accent); text-underline-offset: 3px; }
:focus-visible { outline: 3px solid var(--level); outline-offset: 2px; border-radius: 4px; }

/* masthead + level tabs */
.masthead { border-bottom: 3px double var(--ink); background: var(--paper); }
.masthead-inner { display: flex; flex-wrap: wrap; align-items: baseline; gap: 4px 16px; padding-top: 18px; }
.brand { font-size: 1.75rem; letter-spacing: -0.02em; margin: 0; line-height: 1.1; }
.date { color: var(--ink-soft); font-size: 1rem; }
.game-link {
  margin-left: auto; font-weight: 700; font-size: 1rem; color: var(--marker-ink); text-decoration: none;
  background: var(--marker); padding: 2px 10px; border-radius: var(--radius-s);
}
.tabs { display: flex; gap: 6px; width: 100%; margin-top: 14px; }
.tab {
  flex: 1; appearance: none; border: 0; cursor: pointer; text-align: left;
  padding: 10px 14px 12px; border-radius: var(--radius-l) var(--radius-l) 0 0;
  background: color-mix(in srgb, var(--tab) 12%, transparent); color: var(--ink);
  font-size: 1.05rem; font-weight: 700; line-height: 1.2;
  border-top: 5px solid color-mix(in srgb, var(--tab) 45%, transparent);
}
.tab small { display: block; font-weight: 500; font-size: 0.8rem; color: var(--ink-soft); }
.tab[aria-selected="true"] { background: var(--tab); color: var(--on-level); border-top-color: var(--tab); }
.tab[aria-selected="true"] small { color: color-mix(in srgb, var(--on-level) 80%, transparent); }

/* story */
.story { padding: 28px 0 8px; }
.kicker { margin: 0 0 8px; color: var(--accent); font-size: 0.8rem; font-weight: 700; letter-spacing: 0.08em; text-transform: uppercase; }
.story h1 { font-size: clamp(1.9rem, 6vw, 2.6rem); line-height: 1.1; letter-spacing: -0.02em; margin: 0 0 20px; font-weight: 600; }
.story p { margin: 0 0 1em; max-width: 65ch; }
.hint { color: var(--ink-soft); font-size: 0.95rem; margin: 0 0 18px; }
mark { background: none; color: inherit; }
.w {
  font: inherit; color: var(--marker-ink); cursor: pointer; border: 0; padding: 0 2px; margin: 0 -2px;
  background: linear-gradient(100deg, transparent 0 2%, var(--marker) 3% 96%, transparent 97%) 0 62% / 100% 70% no-repeat;
  border-radius: 3px;
}
.w[aria-expanded="true"] { outline: 2px solid var(--level); }
.pop {
  position: absolute; z-index: 5; max-width: min(20rem, calc(100vw - 32px));
  background: var(--sheet); color: var(--ink); border: 1px solid var(--line); border-left: 5px solid var(--level);
  border-radius: var(--radius-s); padding: 10px 14px; box-shadow: 0 8px 24px rgb(20 30 60 / 0.18);
  font-size: 1rem; line-height: 1.4;
}
.pop b { font-size: 1.1rem; }
.pop .tr { color: var(--level); font-weight: 700; }
.source { font-size: 0.95rem; color: var(--ink-soft); border-top: 1px solid var(--line); padding-top: 12px; }

/* sections */
section { margin: 40px 0; }
h2 { font-size: 1.55rem; letter-spacing: -0.01em; margin: 0 0 6px; }
section > h2 { border-top: 2px solid var(--ink); padding-top: 12px; }
h2 + .hint { margin-bottom: 16px; }
.words { list-style: none; margin: 0; padding: 0; border-top: 1px solid var(--line); }
.words li { display: grid; grid-template-columns: minmax(7rem, 11rem) 1fr; gap: 2px 16px; padding: 12px 0; border-bottom: 1px solid var(--line); }
.words .head b { font-size: 1.15rem; }
.words .pos { display: block; color: var(--ink-soft); font-size: 0.85rem; }
.words .tr { color: var(--accent); font-weight: 700; font-style: italic; }
.words .ex { grid-column: 2; color: var(--ink-soft); font-size: 0.95rem; font-style: italic; border-left: 3px solid var(--accent); background: color-mix(in srgb, var(--ink) 4%, transparent); padding: 6px 10px; margin-top: 6px; }
.review { display: flex; flex-wrap: wrap; gap: 8px; list-style: none; padding: 0; margin: 12px 0 0; }
.review li { border: 1px solid var(--line); background: var(--sheet); border-radius: var(--radius-s); padding: 4px 12px; font-size: 0.95rem; }
.review li span { color: var(--accent); font-style: italic; }

/* exercises */
.score { font-weight: 700; color: var(--accent); }
.task { background: var(--sheet); border: 1px solid var(--line); border-radius: var(--radius-l); padding: 20px; margin: 16px 0; }
.task h3 { font-size: 1.2rem; margin: 0 0 4px; }
.task h3 .n { color: var(--accent); margin-right: 6px; }
.item { padding: 14px 0; border-top: 1px dashed var(--line); }
.item:first-of-type { border-top: 0; }
.q { margin: 0 0 8px; }
.gap { display: inline-block; min-width: 4.5em; border-bottom: 2px solid var(--ink-soft); text-align: center; font-weight: 700; }
.opts { display: flex; flex-direction: column; gap: 8px; counter-reset: opt; }
.opt {
  font: inherit; font-size: 1rem; cursor: pointer; width: 100%; min-height: 48px; padding: 8px 14px; text-align: left;
  display: flex; align-items: center; gap: 12px; border-radius: var(--radius-s);
  border: 1.5px solid var(--line); background: var(--sheet); color: var(--ink);
}
.opt::before {
  counter-increment: opt; content: counter(opt, upper-alpha); flex: none; display: grid; place-items: center;
  width: 1.7rem; height: 1.7rem; border-radius: 50%; background: color-mix(in srgb, var(--ink) 10%, transparent);
  font-size: 0.85rem; font-weight: 700;
}
.opt:hover:not(:disabled) { border-color: var(--accent); }
.opt:disabled { cursor: default; }
.opt.right { background: var(--ok-bg); border-color: var(--ok); color: var(--ok); font-weight: 700; }
.opt.wrong { background: var(--bad-bg); border-color: var(--bad); color: var(--bad); }
.opt.right::before { background: var(--ok); color: var(--ok-bg); }
.opt.wrong::before { background: var(--bad); color: var(--bad-bg); }
.opt.right::after, .opt.wrong::after { margin-left: auto; font-weight: 700; }
.opt.right::after { content: "\2713"; }
.opt.wrong::after { content: "\2715"; }
.fb { font-size: 0.95rem; margin: 6px 0 0; min-height: 1.4em; }
.fb.right { color: var(--ok); } .fb.wrong { color: var(--bad); }
.match { display: grid; grid-template-columns: minmax(6rem, 10rem) 1fr; gap: 10px 14px; align-items: center; }
select { font: inherit; font-size: 1rem; padding: 6px 8px; border-radius: var(--radius-s); border: 1.5px solid var(--line); background: var(--paper); color: var(--ink); width: 100%; }
select.right { border-color: var(--ok); background: var(--ok-bg); } select.wrong { border-color: var(--bad); background: var(--bad-bg); }
textarea { width: 100%; min-height: 6rem; font: inherit; font-size: 1rem; padding: 10px; border-radius: var(--radius-s); border: 1.5px solid var(--line); background: var(--paper); color: var(--ink); }
.btn { font: inherit; font-size: 1rem; font-weight: 700; cursor: pointer; margin-top: 12px; padding: 10px 18px; min-height: 48px; border-radius: var(--radius-s); border: 0; background: var(--accent); color: var(--on-accent); }
.btn.ghost { background: transparent; color: var(--ink); border: 1.5px solid var(--ink); }
.model { margin-top: 12px; padding: 12px 14px; border-left: 4px solid var(--level); background: var(--paper); }

footer { padding-top: 24px; padding-bottom: 48px; border-top: 1px solid var(--line); color: var(--ink-soft); font-size: 0.9rem; }
footer h2 { font-size: 1.1rem; color: var(--ink); }
.archive { list-style: none; padding: 0; margin: 0 0 24px; }
.archive li { padding: 4px 0; }
.archive time { display: inline-block; min-width: 7.5em; }

@media (max-width: 520px) {
  body { font-size: 1.125rem; }
  .tab { padding: 8px 10px 10px; font-size: 1rem; }
  .words li { grid-template-columns: 1fr; }
  .words .ex { grid-column: 1; }
  .match { grid-template-columns: 1fr; gap: 4px; }
  .match select { margin-bottom: 10px; }
}
@media (prefers-reduced-motion: no-preference) {
  .opt, .tab, select { transition: background-color .15s, border-color .15s, color .15s; }
}