:root {
  --bg: #faf8f3;
  --surface: #ffffff;
  --fg: #1f1d1a;
  --muted: #6b665d;
  --line: #e4dfd4;
  --accent: #2f6f5e;
  --accent-fg: #ffffff;
  --ok: #2e7d4f;
  --ok-bg: #e7f4ec;
  --bad: #b3402e;
  --bad-bg: #fbebe7;
  --warn-bg: #fbf1dc;
  --radius: .75rem;
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  font-size: 17px;
  color-scheme: light dark;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #16181b; --surface: #1f2226; --fg: #e8e6e1; --muted: #9a968d; --line: #33373c;
    --accent: #6fbfa6; --accent-fg: #10221d; --ok: #7fd3a0; --ok-bg: #1d3327; --bad: #f08a76; --bad-bg: #3a221d; --warn-bg: #3a311d;
  }
}
* { box-sizing: border-box; }
body { margin: 0; background: var(--bg); color: var(--fg); line-height: 1.45; }
a { color: var(--accent); }

/* ---------- shell: menu mode (rail) / focus mode (back bar) ---------- */
.topbar, .focus-head {
  display: flex; align-items: center; gap: .75rem;
  max-width: 64rem; margin: 0 auto; padding: .75rem 1rem;
}
.topbar { justify-content: space-between; }
.brand { font-weight: 700; font-size: 1.2rem; text-decoration: none; }
.focus-head { display: none; }
.back { text-decoration: none; font-size: 1.4rem; line-height: 1; padding: .1rem .4rem; }
.focus-title { font-weight: 600; font-size: 1.1rem; }
#app[data-mode="focus"] .topbar, #app[data-mode="focus"] .rail { display: none; }
#app[data-mode="focus"] .focus-head { display: flex; }

.app-body { max-width: 64rem; margin: 0 auto; padding: 0 1rem 2rem; }
.view { max-width: 40rem; margin: 0 auto; min-width: 0; }
.rail { display: flex; gap: .4rem; overflow-x: auto; padding: 0 0 .75rem; margin-bottom: .5rem; scrollbar-width: none; }
.rail::-webkit-scrollbar { display: none; }
.rail-item {
  flex: none; padding: .45rem .8rem; border: 1px solid var(--line); border-radius: 2rem;
  background: var(--surface); color: var(--fg); text-decoration: none; font-size: .9rem; white-space: nowrap;
}
.rail-item.active { background: var(--accent); border-color: var(--accent); color: var(--accent-fg); }
@media (min-width: 860px) {
  #app[data-mode="menu"] .app-body { display: grid; grid-template-columns: 13rem 1fr; gap: 2rem; align-items: start; }
  .rail { flex-direction: column; overflow: visible; position: sticky; top: 1rem; }
  .rail-item { border-radius: var(--radius); }
}

/* ---------- dashboard & sections ---------- */
.block { margin-bottom: 1.25rem; }
.block > h3, .view h3 { font-size: .8rem; text-transform: uppercase; letter-spacing: .06em; color: var(--muted); margin: 1.25rem 0 .5rem; }
.today { display: grid; gap: .5rem; }
.cta {
  display: flex; flex-direction: column; gap: .15rem; padding: 1rem 1.1rem; border-radius: var(--radius);
  background: var(--accent); color: var(--accent-fg); text-decoration: none;
}
.cta b { font-size: 1.25rem; }
.cta span { opacity: .9; font-size: .9rem; }
.ex-list { display: grid; gap: .5rem; }
.ex-card { display: grid; grid-template-columns: 1fr auto; gap: .5rem; align-items: stretch; }
.ex-item {
  display: flex; flex-direction: column; gap: .15rem; padding: .75rem .9rem; border: 1px solid var(--line);
  border-radius: var(--radius); background: var(--surface); color: var(--fg); text-decoration: none;
}
a.ex-item:hover { border-color: var(--accent); }
.ex-item.disabled { opacity: .6; }
.ex-label { font-weight: 600; }
.ex-desc { color: var(--muted); font-size: .85rem; }
.soon { margin-left: .5rem; font-size: .7rem; font-weight: 400; padding: .05rem .45rem; border-radius: 1rem; border: 1px solid var(--line); color: var(--muted); }
.star {
  width: 3rem; border: 1px solid var(--line); border-radius: var(--radius); background: var(--surface);
  color: var(--line); font-size: 1.3rem; cursor: pointer;
}
.star[aria-pressed="true"] { color: #e0a42b; border-color: #e0a42b; }

/* ---------- stats ---------- */
.tiles-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: .5rem; }
.tiles-grid.three { grid-template-columns: repeat(3, 1fr); }
@media (min-width: 560px) { .tiles-grid { grid-template-columns: repeat(4, 1fr); } }
.seg-bar { display: flex; height: .8rem; border-radius: 1rem; overflow: hidden; background: var(--line); }
.seg-learned { background: var(--ok); }
.seg-learning { background: #e0a42b; }
.seg-new { background: var(--muted); }
.seg-legend { display: flex; flex-wrap: wrap; gap: .4rem 1rem; margin-top: .5rem; font-size: .85rem; color: var(--muted); }
.dot { display: inline-block; width: .6rem; height: .6rem; border-radius: 50%; margin-right: .3rem; }
.chart { display: grid; grid-template-columns: repeat(14, 1fr); gap: .25rem; height: 7rem; align-items: end; }
.chart .col { display: flex; flex-direction: column; justify-content: flex-end; align-items: center; height: 100%; gap: .2rem; }
.chart .bar { width: 100%; min-height: 2px; border-radius: .25rem .25rem 0 0; background: var(--accent); opacity: .55; }
.chart .bar.goal { opacity: 1; }
.chart small { font-size: .65rem; color: var(--muted); }

.muted { color: var(--muted); }
.small { font-size: .85rem; }
.error { color: var(--bad); }
.warn { margin: .5rem 0 .25rem; }
.notice, .panel { background: var(--warn-bg); padding: .75rem 1rem; border-radius: var(--radius); }
.panel { background: var(--surface); border: 1px solid var(--line); }

.button {
  display: inline-block; padding: .7rem 1.2rem; border-radius: var(--radius); border: 1px solid var(--accent);
  background: var(--accent); color: var(--accent-fg); font: inherit; text-decoration: none; cursor: pointer; text-align: center;
}
.button.secondary { background: transparent; color: var(--accent); }
.button.big { display: block; width: 100%; padding: .9rem 1.2rem; font-size: 1.1rem; }
.button:disabled { opacity: .5; }
.link { background: none; border: 0; color: var(--muted); font: inherit; cursor: pointer; text-decoration: underline; }
.icon { background: none; border: 0; font-size: 1.2rem; cursor: pointer; padding: 0 .25rem; }

.greeting { font-size: 1.2rem; margin: .5rem 0 1rem; }
.stats { display: grid; grid-template-columns: repeat(3, 1fr); gap: .5rem; margin-bottom: 1rem; }
.stat { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); padding: .75rem; text-align: center; }
.stat b { display: block; font-size: 1.6rem; }
.stat span { color: var(--muted); font-size: .85rem; }
.actions { display: grid; gap: .75rem; }

.deck-list { list-style: none; padding: 0; margin: 0 0 1rem; }
.deck-list li { padding: .6rem 0; border-bottom: 1px solid var(--line); display: flex; flex-direction: column; }
.deck-list label { display: flex; gap: .6rem; align-items: center; cursor: pointer; }
.deck-list input { width: 1.2rem; height: 1.2rem; accent-color: var(--accent); }
.deck-list small { margin-left: 1.8rem; }
.later { margin-bottom: 1rem; }
.later summary { cursor: pointer; color: var(--muted); padding: .5rem 0; }

.progress { margin: .25rem 0 .75rem; }
.card { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); padding: 1.25rem 1rem; }
.card.ok { border-color: var(--ok); background: var(--ok-bg); }
.card.bad { border-color: var(--bad); background: var(--bad-bg); }
.prompt { font-size: 1.5rem; font-weight: 600; margin-bottom: .5rem; overflow-wrap: anywhere; }
.badges { display: flex; gap: .4rem; margin-bottom: 1rem; }
.badge { font-size: .75rem; padding: .1rem .5rem; border-radius: 1rem; border: 1px solid var(--line); color: var(--muted); }
.badge.new { border-color: var(--accent); color: var(--accent); }
.answer-form { display: grid; gap: .75rem; }
.answer {
  width: 100%; font: inherit; font-size: 1.25rem; padding: .7rem .8rem; border-radius: var(--radius);
  border: 1px solid var(--line); background: var(--bg); color: var(--fg);
}
.answer:focus { outline: 2px solid var(--accent); outline-offset: 1px; }
.row { display: grid; grid-template-columns: 1fr 1fr; gap: .5rem; }
.verdict { font-weight: 700; margin: .5rem 0 0; }
.ok .verdict { color: var(--ok); }
.bad .verdict { color: var(--bad); }
.expected { font-size: 1.4rem; font-weight: 600; margin: .25rem 0 .5rem; overflow-wrap: anywhere; }

.hint { margin-top: .75rem; }
.tiles { display: flex; flex-wrap: wrap; gap: .3rem; margin-top: .25rem; }
.tile { border: 1px solid var(--line); border-radius: .4rem; padding: .15rem .45rem; font-weight: 600; }
.tile sub { color: var(--muted); font-weight: 400; margin-left: .1rem; }
.tile.used { opacity: .35; }
.tile.over { border-color: var(--bad); color: var(--bad); opacity: 1; }

.diff { font-family: ui-monospace, Consolas, monospace; font-size: 1.15rem; letter-spacing: .05em; }
.diff-line { margin: .2rem 0; }
mark.strike { background: none; color: var(--bad); text-decoration: line-through; }
mark.hi { background: var(--ok-bg); color: var(--ok); font-weight: 700; }