:root {
  --bg: #f6f5f1;
  --surface: #ffffff;
  --surface-2: #efede7;
  --text: #1f2328;
  --muted: #6b6f76;
  --border: #e2dfd7;
  --accent: #3b5bdb;
  --accent-soft: #e7ecff;
  --on-accent: #ffffff;
  --good: #2b8a3e;
  --good-soft: #e3f5e6;
  --bad: #c92a2a;
  --bad-soft: #fde8e8;
  --radius: 14px;
  --shadow: 0 1px 2px rgba(0, 0, 0, .05), 0 4px 14px rgba(0, 0, 0, .05);
  /* interval steps: new → 1d → 3d → 1w → 2w → 1m → learned */
  --s0: #adb5bd; --s1: #ffa94d; --s2: #ffd43b; --s3: #a9e34b; --s4: #51cf66; --s5: #22b8cf; --s6: #4c6ef5;
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #15171b;
    --surface: #1e2127;
    --surface-2: #272b33;
    --text: #e8e9ec;
    --muted: #9aa0aa;
    --border: #323741;
    --accent: #7c95ff;
    --accent-soft: #252d4a;
    --on-accent: #10131a;
    --good: #69db7c;
    --good-soft: #1f3324;
    --bad: #ff8787;
    --bad-soft: #3a2224;
    --shadow: none;
    color-scheme: dark;
  }
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }
.in-tg #back { display: none !important; }
.in-tg .top { padding-top: 10px; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 16px/1.45 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}
.page, .top { max-width: 640px; margin: 0 auto; padding: 0 16px; }
.page { padding-bottom: 48px; }
a { color: var(--accent); }
h3 { margin: 0 0 8px; font-size: 1.05rem; }
hr { border: 0; border-top: 1px solid var(--border); margin: 16px 0; width: 100%; }
kbd { font: 11px/1 ui-monospace, monospace; border: 1px solid currentColor; border-radius: 4px; padding: 2px 4px; opacity: .55; }
.muted { color: var(--muted); }
.small { font-size: .85rem; }
.center { text-align: center; }
.row { display: flex; gap: 8px; flex-wrap: wrap; align-items: center; margin: 8px 0; }

/* header + period filter */
.top { display: flex; align-items: center; gap: 8px; padding-top: 16px; margin-bottom: 16px; position: relative; }
.top h1 { font-size: 1.4rem; margin: 0; min-width: 0; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.filter-wrap { margin-left: auto; position: relative; flex: none; }
.filter-btn {
  font: inherit; font-size: .9rem; display: inline-flex; align-items: center; gap: 6px; height: 38px; min-width: 38px;
  padding: 0 10px; border-radius: 999px; border: 1px solid var(--border); background: var(--surface-2);
  color: var(--text); cursor: pointer; position: relative; justify-content: center;
}
.filter-btn span[aria-hidden] { font-size: 1.1rem; }
.filter-btn:hover { border-color: var(--accent); }
.filter-btn.active { background: var(--accent-soft); border-color: var(--accent); color: var(--accent); font-weight: 600; }
.filter-btn.active::after {
  content: ""; position: absolute; top: 2px; right: 2px; width: 8px; height: 8px;
  border-radius: 50%; background: var(--accent); border: 2px solid var(--bg);
}
.filter-panel {
  position: absolute; right: 0; top: calc(100% + 8px); z-index: 20; width: 320px;
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 12px 14px; box-shadow: 0 8px 30px rgba(0, 0, 0, .18);
}
.panel-head { display: flex; justify-content: space-between; align-items: center; margin-bottom: 4px; }
.panel-count { margin: 10px 0 0; padding-top: 10px; border-top: 1px solid var(--border); }
.filter-panel select { width: 100%; margin: 4px 0; }
input[type=date], select {
  font: inherit; color: var(--text); background: var(--surface-2);
  border: 1px solid var(--border); border-radius: 8px; padding: 5px 8px;
}
.check { gap: 6px; font-size: .95rem; flex-wrap: nowrap; align-items: flex-start; }
.check input { margin-top: 4px; flex: none; }
.chip {
  font: inherit; font-size: .9rem; border: 1px solid var(--border); background: var(--surface-2);
  color: var(--text); padding: 4px 10px; border-radius: 999px; cursor: pointer;
}
.chip.on { background: var(--accent); border-color: var(--accent); color: var(--on-accent); }

/* buttons */
.btn {
  font: inherit; display: inline-flex; align-items: center; justify-content: center; gap: 6px;
  padding: 10px 16px; border-radius: 10px; border: 1px solid var(--border);
  background: var(--surface); color: var(--text); cursor: pointer; text-decoration: none;
}
.btn:hover { border-color: var(--accent); }
.btn:disabled { opacity: .5; cursor: default; }
.btn.primary { background: var(--accent); border-color: var(--accent); color: var(--on-accent); }
.btn.good { background: var(--good-soft); border-color: var(--good); color: var(--good); }
.btn.bad { background: var(--bad-soft); border-color: var(--bad); color: var(--bad); }
.btn.danger { color: var(--bad); }
.btn.small { padding: 5px 10px; font-size: .85rem; margin-top: 8px; }
.btn.wide { width: 100%; margin-top: 12px; }
.link { font: inherit; background: none; border: 0; color: var(--accent); text-decoration: underline; cursor: pointer; padding: 0; }
.icon-btn {
  font-size: 1.2rem; line-height: 1; background: var(--surface-2); border: 1px solid var(--border);
  border-radius: 999px; width: 38px; height: 38px; flex: none; cursor: pointer; color: var(--text);
  display: inline-flex; align-items: center; justify-content: center; text-decoration: none;
}
.icon-btn:hover { border-color: var(--accent); }
.icon-btn.small { width: 30px; height: 30px; font-size: .9rem; }
.speak-row { display: flex; gap: 8px; justify-content: center; margin: 8px 0; }
.speak-row.large .icon-btn { width: 72px; height: 72px; font-size: 2rem; }

/* home */
.tiles { display: grid; grid-template-columns: repeat(2, 1fr); gap: 12px; }
.tile {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 16px; text-decoration: none; color: var(--text); display: flex; flex-direction: column; gap: 4px;
  box-shadow: var(--shadow); transition: transform .1s, border-color .1s;
}
.tile:hover { transform: translateY(-2px); border-color: var(--accent); }
.tile:first-child { grid-column: 1 / -1; }
.tile.accent { background: var(--accent-soft); border-color: var(--accent); }
.tile-icon { font-size: 1.8rem; }
.tile-title { font-weight: 600; font-size: 1.05rem; }
.tile-sub { color: var(--muted); font-size: .9rem; }

/* cards / generic */
.card {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 18px; margin-bottom: 12px; box-shadow: var(--shadow);
}
.card.accent { background: var(--accent-soft); border-color: var(--accent); }
.big { font-size: 1.7rem; font-weight: 650; line-height: 1.2; overflow-wrap: anywhere; }
.big.ru { font-size: 1.4rem; font-weight: 550; }
.ru { font-size: 1.1rem; }
.ipa { color: var(--muted); font-family: "Segoe UI", "Lucida Sans Unicode", sans-serif; }
.example { color: var(--muted); font-style: italic; margin-top: 6px; }
.example::before { content: "✎ "; font-style: normal; }
.example.ai { opacity: .85; }
.example.ai::before { content: "💡 "; }
.toolbar { display: flex; justify-content: space-between; align-items: center; gap: 8px; margin-bottom: 10px; flex-wrap: wrap; }
.score { font-weight: 600; }
.seg { display: inline-flex; border: 1px solid var(--border); border-radius: 10px; overflow: hidden; }
.seg button { font: inherit; font-size: .9rem; border: 0; background: var(--surface); color: var(--text); padding: 6px 12px; cursor: pointer; }
.seg button.on { background: var(--accent); color: var(--on-accent); }
.progress { height: 6px; background: var(--surface-2); border-radius: 99px; overflow: hidden; }
.progress div { height: 100%; background: var(--accent); transition: width .2s; }
.flashcard {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  min-height: 240px; margin: 12px 0; padding: 24px 18px; display: flex; flex-direction: column;
  align-items: center; justify-content: center; text-align: center; cursor: pointer; box-shadow: var(--shadow);
}
.flashcard.flipped { cursor: default; }
.hint { margin-top: 16px; }
.answer-row { display: flex; gap: 10px; margin-top: 10px; }
.answer-row .btn { flex: 1; }
.answer-row[hidden] { display: none; }
.feedback { border-radius: 10px; padding: 12px 14px; margin-top: 12px; }
.feedback.good { background: var(--good-soft); color: var(--good); }
.feedback.bad { background: var(--bad-soft); color: var(--bad); }
.feedback .example { color: inherit; opacity: .8; }
.note { background: var(--surface-2); border-radius: 8px; padding: 8px 12px; font-size: .9rem; }

/* quiz */
.options { display: grid; gap: 8px; }
.option {
  font: inherit; text-align: left; padding: 12px 14px; border-radius: 10px; cursor: pointer;
  border: 1px solid var(--border); background: var(--surface); color: var(--text);
}
.option:hover:not(:disabled) { border-color: var(--accent); }
.option.right { background: var(--good-soft); border-color: var(--good); color: var(--good); }
.option.wrong { background: var(--bad-soft); border-color: var(--bad); color: var(--bad); }
.option kbd { margin-right: 6px; }

/* hangman */
.hangman { display: flex; flex-direction: column; align-items: center; gap: 10px; margin-top: 10px; }
.gallows { width: 130px; height: 140px; stroke: var(--text); stroke-width: 3; fill: none; stroke-linecap: round; }
.gallows .frame { stroke: var(--muted); }
.gallows .man { stroke: var(--bad); }
.word { display: flex; flex-wrap: wrap; justify-content: center; gap: 5px; }
.letter {
  width: 26px; height: 34px; border-bottom: 3px solid var(--text); font-size: 1.4rem; font-weight: 600;
  display: inline-flex; align-items: flex-end; justify-content: center; text-transform: lowercase;
}
.letter.fixed { border-color: transparent; }
.letter.missed { color: var(--bad); }
.gap { width: 14px; }
.keyboard { display: flex; flex-direction: column; gap: 6px; align-items: center; margin-top: 12px; }
.keyboard div { display: flex; gap: 5px; }
.key {
  font: inherit; font-weight: 600; width: min(8.5vw, 40px); height: 44px; border-radius: 8px; cursor: pointer;
  border: 1px solid var(--border); background: var(--surface); color: var(--text);
}
.key.hit { background: var(--good-soft); color: var(--good); border-color: var(--good); }
.key.miss { background: var(--surface-2); color: var(--muted); }

/* listen / typing */
.answer {
  font: inherit; font-size: 1.3rem; width: 100%; padding: 12px 14px; border-radius: 10px;
  border: 2px solid var(--border); background: var(--surface); color: var(--text); outline: none;
}
.answer:focus { border-color: var(--accent); }
.answer.good { border-color: var(--good); }
.answer.bad { border-color: var(--bad); }
.diff { font: 1.3rem ui-monospace, monospace; letter-spacing: 1px; margin-bottom: 6px; }
.diff .ok { color: var(--good); }
.diff .add { color: var(--text); background: var(--good-soft); text-decoration: underline; }
.diff .del { color: var(--bad); text-decoration: line-through; }

/* word list */
.search { font: inherit; width: 100%; padding: 10px 14px; border-radius: 10px; border: 1px solid var(--border); background: var(--surface); color: var(--text); margin-bottom: 8px; }
.month { margin: 18px 0 6px; color: var(--muted); font-weight: 600; text-transform: capitalize; }
.word-row { display: flex; gap: 10px; align-items: flex-start; padding: 10px 0; border-bottom: 1px solid var(--border); text-align: left; }
.word-row > div { flex: 1; min-width: 0; }
.badge { font-size: .75rem; background: var(--bad-soft); color: var(--bad); border-radius: 6px; padding: 1px 6px; }
.badge.added { background: var(--accent-soft); color: var(--accent); }
.row-side { display: flex; flex-direction: column; align-items: flex-end; gap: 6px; flex: none; }

/* cloze */
.cloze-sentence { font-size: 1.3rem; line-height: 1.6; margin: 0 0 8px; }
.cloze-gap {
  display: inline-block; border-bottom: 3px solid var(--accent); color: var(--accent); font-weight: 600;
  padding: 0 2px; margin: 0 2px; letter-spacing: 1px;
}
.cloze-sentence mark { background: var(--good-soft); color: var(--good); font-weight: 600; border-radius: 4px; padding: 0 3px; }

/* add words */
textarea {
  font: inherit; font-size: .95rem; width: 100%; padding: 10px 12px; border-radius: 10px; resize: vertical;
  border: 1px solid var(--border); background: var(--surface-2); color: var(--text);
}
code { font-size: .85em; background: var(--surface-2); border-radius: 4px; padding: 1px 4px; }
.add-row { display: grid; gap: 6px; padding: 12px 14px; }
.add-row.off { opacity: .55; }
.add-row.need { border-color: var(--bad); }
.add-row.need [data-f="ru"] { border-color: var(--bad); }
.field {
  font: inherit; width: 100%; padding: 7px 10px; border-radius: 8px;
  border: 1px solid var(--border); background: var(--surface-2); color: var(--text);
}
.field[data-f="en"] { font-weight: 600; }
.mistakes { text-align: left; margin: 12px 0; }

/* tracker */
.today-card { text-align: center; }
.section { margin: 20px 0 8px; }
.stepbar { display: flex; height: 22px; border-radius: 6px; overflow: hidden; margin-top: 8px; font-size: .75rem; font-weight: 600; }
.stepbar > div { display: flex; align-items: center; justify-content: center; color: #1f2328; min-width: 18px; }
.s0 { background: var(--s0); } .s1 { background: var(--s1); } .s2 { background: var(--s2); } .s3 { background: var(--s3); }
.s4 { background: var(--s4); } .s5 { background: var(--s5); } .s6 { background: var(--s6); color: #fff !important; }
.pill { display: inline-block; font-size: .75rem; border-radius: 99px; padding: 1px 8px; color: #1f2328; white-space: nowrap; }
.legend { display: flex; flex-wrap: wrap; gap: 6px; justify-content: center; margin: 12px 0 16px; }
.group summary { cursor: pointer; list-style: none; }
.group summary::-webkit-details-marker { display: none; }
.group-head { display: flex; justify-content: space-between; gap: 8px; flex-wrap: wrap; }
.group-words { width: 100%; border-collapse: collapse; margin-top: 12px; }
.group-words td { padding: 6px 4px; border-top: 1px solid var(--border); vertical-align: top; }
.group-words td:last-child { text-align: right; }
.forecast { display: flex; align-items: flex-end; gap: 2px; height: 120px; padding-top: 14px; }
.forecast .day { flex: 1; height: 100%; display: flex; flex-direction: column; justify-content: flex-end; align-items: stretch; min-width: 0; }
.forecast .bar { background: var(--accent); border-radius: 3px 3px 0 0; min-height: 2px; opacity: .75; position: relative; }
.forecast .bar span { position: absolute; left: -4px; right: -4px; top: -14px; font-size: .65rem; line-height: 12px; text-align: center; color: var(--text); }
.forecast .today .bar { opacity: 1; background: var(--bad); }
.forecast .dlabel { font-size: .65rem; color: var(--muted); text-align: center; height: 14px; line-height: 14px; }

/* speak off the cuff */
.wheel-wrap { position: relative; width: min(320px, 100%); aspect-ratio: 1; margin: 4px auto 12px; }
.wheel { width: 100%; height: 100%; display: block; border-radius: 50%; box-shadow: var(--shadow); }
.wheel.spinning { transition: transform 4.2s cubic-bezier(.12, .7, .15, 1); }
.wheel path { stroke: var(--surface); stroke-width: 1.5; }
.wheel text { font: 600 11px system-ui, -apple-system, "Segoe UI", Roboto, sans-serif; fill: #1f2328; }
.wheel-pointer {
  position: absolute; top: -6px; left: 50%; transform: translateX(-50%); z-index: 2; width: 0; height: 0;
  border-left: 13px solid transparent; border-right: 13px solid transparent; border-top: 24px solid var(--text);
  filter: drop-shadow(0 1px 1px rgba(0, 0, 0, .25));
}
.wheel-hub {
  position: absolute; top: 50%; left: 50%; transform: translate(-50%, -50%); width: 76px; height: 76px;
  border-radius: 50%; border: 4px solid var(--surface); background: var(--accent); color: var(--on-accent);
  font: inherit; font-weight: 700; font-size: 1.05rem; cursor: pointer; box-shadow: 0 2px 10px rgba(0, 0, 0, .25);
}
.wheel-hub:disabled { opacity: .85; cursor: default; }
.cuff-summary { line-height: 1.3; }
.cuff-settings .chips { gap: 6px; }
.reminder-body.off { opacity: .55; }
.time-input {
  font: inherit; color: var(--text); background: var(--surface-2);
  border: 1px solid var(--border); border-radius: 8px; padding: 5px 8px; margin-left: 6px;
}
.chip:disabled { cursor: default; }
.cuff-topic .big { margin: 2px 0 6px; }
.cuff-q { font-size: 1.15rem; margin: 0 0 6px; }
.cuff-topic .chip { cursor: default; }
.timer { font: 700 3.4rem/1.1 ui-monospace, "SF Mono", Menlo, monospace; margin: 6px 0 12px; font-variant-numeric: tabular-nums; }
.timer.over { color: var(--good); }
.timer.small-timer { font-size: 1.6rem; margin: 0 0 10px; }
.rec-dot { display: inline-flex; align-items: center; gap: 6px; color: var(--bad); font-weight: 700; font-size: .85rem; letter-spacing: 1px; }
.rec-dot span { width: 10px; height: 10px; border-radius: 50%; background: var(--bad); animation: rec-blink 1.2s infinite; }
@keyframes rec-blink { 50% { opacity: .2; } }
.cuff-timer .progress { margin-bottom: 8px; }
.cuff-audio { width: 100%; margin-bottom: 4px; }
.good-text { color: var(--good); font-weight: 600; }
.bad-text { color: var(--bad); }
@media (prefers-reduced-motion: reduce) { .wheel.spinning { transition-duration: .6s; } .rec-dot span { animation: none; } }

/* grammar */
.grammar-item { display: flex; align-items: center; gap: 12px; width: 100%; margin-bottom: 8px; }
.grammar-item.current { border-color: var(--accent); background: var(--accent-soft); }
.grammar-item .unit { font-weight: 700; color: var(--accent); min-width: 34px; }
.grammar-item .gi-text { flex: 1; min-width: 0; display: flex; flex-direction: column; gap: 2px; }
.grammar-item .badge { flex: none; }
.grammar-rule h2 { margin: 2px 0 4px; font-size: 1.4rem; }
.grammar-rule h4 { margin: 18px 0 6px; font-size: 1rem; }
.grammar-rule ul { padding-left: 20px; margin: 6px 0; }
.grammar-rule li { margin: 6px 0; }
.grammar-rule .ex { display: inline; font-style: italic; color: var(--accent); }
.cloze-sentence mark.fix { background: var(--bad-soft); color: var(--bad); }
#gap-form .answer { flex: 1; }
#gap-form .lead { width: 100%; color: var(--muted); }
.grammar-tabs { margin: 10px 0; display: flex; }
.grammar-tabs button { flex: 1; }
.task-head { font-size: .85rem; font-weight: 600; color: var(--accent); margin-bottom: 4px; }
.task-head.muted { color: var(--muted); font-weight: 400; }
.fix-phrase { background: var(--accent-soft); color: var(--accent); font-weight: 600; border-radius: 4px; padding: 0 3px; }
.book-text h4 { margin: 16px 0 6px; }
.book-text .ex-box { background: var(--surface-2); border-radius: 8px; padding: 8px 12px; margin: 6px 0; }
.book-text .ex-box p { margin: 3px 0; }
.book-text ol { padding-left: 20px; }
.book-text .dm-table { width: 100%; border-collapse: collapse; font-size: .92rem; }
.book-text .dm-table td, .book-text .dm-table th { border-top: 1px solid var(--border); padding: 6px 4px; vertical-align: top; text-align: left; }
.book-text .dm-table td:first-child { width: 55%; }
.book-text .warn { border-left: 3px solid var(--bad); padding-left: 10px; margin: 8px 0; }

/* touch screens: keyboard shortcut hints are noise */
@media (hover: none) and (pointer: coarse) { kbd { display: none; } }

@media (max-width: 420px) {
  .filter-wrap { position: static; }
  .filter-panel { left: 16px; right: 16px; width: auto; }
  .tiles { grid-template-columns: 1fr 1fr; gap: 8px; }
  .tile { padding: 12px; }
  .big { font-size: 1.45rem; }
  .answer-row { flex-direction: column; }
}