/* B1 Grammatik Trainer — exercise-book look: cool paper, slate ink, fountain-pen blue,
   red pen for corrections, one marker-yellow for the gap. */
:root {
  --paper: #f3f5f8;
  --card: #ffffff;
  --ink: #1f2933;
  --ink-2: #566371;
  --line: #d8dfe7;
  --blue: #2b55b2;
  --blue-soft: #e4ebf9;
  --red: #c0392b;
  --red-soft: #fbe9e7;
  --green: #25794f;
  --green-soft: #e2f3ea;
  --marker: #fff0a3;
  --shadow: 0 1px 2px rgba(31, 41, 51, .06), 0 6px 20px -12px rgba(31, 41, 51, .18);
  --radius: 14px;
  --font-ui: "Atkinson Hyperlegible", system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-de: "Literata", Georgia, "Times New Roman", serif;
  --fs: 18px;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --paper: #151a20; --card: #1d242c; --ink: #e7ebef; --ink-2: #9ba6b2; --line: #2f3944;
    --blue: #8db0ff; --blue-soft: #233351; --red: #f2857a; --red-soft: #3d2320;
    --green: #62c698; --green-soft: #1d3a2d; --marker: #5a5120;
    --shadow: 0 1px 2px rgba(0,0,0,.3), 0 8px 24px -12px rgba(0,0,0,.6);
  }
}
:root[data-theme="dark"] {
  --paper: #151a20; --card: #1d242c; --ink: #e7ebef; --ink-2: #9ba6b2; --line: #2f3944;
  --blue: #8db0ff; --blue-soft: #233351; --red: #f2857a; --red-soft: #3d2320;
  --green: #62c698; --green-soft: #1d3a2d; --marker: #5a5120;
  --shadow: 0 1px 2px rgba(0,0,0,.3), 0 8px 24px -12px rgba(0,0,0,.6);
}
:root[data-fs="small"] { --fs: 16px; }
:root[data-fs="large"] { --fs: 20px; }

* { box-sizing: border-box; }
html { font-size: var(--fs); -webkit-text-size-adjust: 100%; }
body {
  margin: 0; background: var(--paper); color: var(--ink);
  font-family: var(--font-ui); line-height: 1.55;
  min-height: 100vh; padding-bottom: 72px;
}
@media (min-width: 900px) { body { padding-bottom: 0; padding-left: 220px; } }
button, input { font: inherit; color: inherit; }
button { cursor: pointer; }
a { color: var(--blue); }
:focus-visible { outline: 3px solid var(--blue); outline-offset: 2px; }
h1, h2, h3 { line-height: 1.2; margin: 0 0 .5rem; font-weight: 700; }
h1 { font-size: 1.6rem; } h2 { font-size: 1.25rem; } h3 { font-size: 1.05rem; }
p { margin: 0 0 .75rem; }
.muted { color: var(--ink-2); }
.small { font-size: .9rem; }
.de { font-family: var(--font-de); }

/* ---------- shell ---------- */
.top {
  position: sticky; top: 0; z-index: 5; background: var(--paper);
  display: flex; align-items: center; justify-content: space-between; gap: 12px;
  padding: 10px 16px; border-bottom: 1px solid var(--line);
}
.top .brand { font-weight: 700; letter-spacing: .01em; }
.top .brand span { color: var(--blue); }
.top .actions { display: flex; gap: 6px; }
main { max-width: 760px; margin: 0 auto; padding: 16px 16px 32px; }
@media (min-width: 900px) {
  main { padding: 28px 32px 48px; }
  .top { position: fixed; top: 14px; right: 20px; left: auto; border: 0; background: transparent; padding: 0; }
  .top .brand { display: none; }
}

nav.tabs {
  position: fixed; left: 0; right: 0; bottom: 0; z-index: 6;
  display: grid; grid-template-columns: repeat(5, 1fr);
  background: var(--card); border-top: 1px solid var(--line);
  padding: 4px 4px calc(4px + env(safe-area-inset-bottom));
}
nav.tabs button {
  background: none; border: 0; border-radius: 10px; padding: 6px 2px 4px;
  display: flex; flex-direction: column; align-items: center; gap: 2px;
  color: var(--ink-2); font-size: .72rem; min-height: 52px;
}
nav.tabs button svg { width: 24px; height: 24px; }
nav.tabs button.active { color: var(--blue); background: var(--blue-soft); }
@media (min-width: 900px) {
  nav.tabs {
    top: 0; bottom: 0; right: auto; width: 220px; padding: 20px 12px;
    grid-template-columns: 1fr; grid-auto-rows: max-content; gap: 4px;
    border-top: 0; border-right: 1px solid var(--line);
  }
  nav.tabs .rail-brand { font-weight: 700; font-size: 1.15rem; padding: 4px 12px 20px; }
  nav.tabs .rail-brand span { color: var(--blue); }
  nav.tabs button { flex-direction: row; gap: 12px; font-size: 1rem; padding: 10px 12px; min-height: 44px; justify-content: flex-start; }
}
nav.tabs .rail-brand { display: none; }
@media (min-width: 900px) { nav.tabs .rail-brand { display: block; } }

/* ---------- primitives ---------- */
.card {
  background: var(--card); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 18px; margin-bottom: 14px; box-shadow: var(--shadow);
}
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  min-height: 48px; padding: 10px 18px; border-radius: 12px;
  border: 1px solid var(--line); background: var(--card); color: var(--ink);
  font-weight: 600; text-decoration: none;
}
.btn:hover { border-color: var(--blue); }
.btn.primary { background: var(--blue); border-color: var(--blue); color: #fff; }
:root[data-theme="dark"] .btn.primary, :root:not([data-theme="light"]) .btn.primary { color: var(--paper); }
@media (prefers-color-scheme: light) { :root:not([data-theme="dark"]) .btn.primary { color: #fff; } }
.btn.quiet { border-color: transparent; background: transparent; color: var(--blue); }
.btn.small { min-height: 38px; padding: 6px 12px; font-size: .9rem; }
.btn.block { width: 100%; }
.btn:disabled { opacity: .5; cursor: default; }
.row { display: flex; flex-wrap: wrap; gap: 10px; align-items: center; }
.row.between { justify-content: space-between; }
.stack > * + * { margin-top: 10px; }
.icon-btn { width: 44px; height: 44px; border-radius: 12px; border: 1px solid var(--line); background: var(--card); display: inline-grid; place-items: center; }
.icon-btn svg { width: 22px; height: 22px; }
.chip {
  display: inline-flex; align-items: center; min-height: 40px; padding: 6px 14px; border-radius: 999px;
  border: 1px solid var(--line); background: var(--card); font-size: .95rem;
}
.chip.on { background: var(--blue-soft); border-color: var(--blue); color: var(--blue); font-weight: 600; }
.seg { display: inline-flex; border: 1px solid var(--line); border-radius: 12px; overflow: hidden; }
.seg button { border: 0; background: var(--card); padding: 10px 14px; min-height: 44px; font-weight: 600; color: var(--ink-2); }
.seg button + button { border-left: 1px solid var(--line); }
.seg button.on { background: var(--blue); color: #fff; }
.callout { border-left: 4px solid var(--red); background: var(--red-soft); padding: 10px 14px; border-radius: 8px; }
.callout.blue { border-color: var(--blue); background: var(--blue-soft); }
.callout.green { border-color: var(--green); background: var(--green-soft); }
.bar { height: 8px; background: var(--line); border-radius: 999px; overflow: hidden; }
.bar > i { display: block; height: 100%; background: var(--blue); border-radius: 999px; transition: width .3s; }
.bar.green > i { background: var(--green); }
table.grid { width: 100%; border-collapse: collapse; font-size: .95rem; }
table.grid th, table.grid td { text-align: left; padding: 6px 8px; border-bottom: 1px solid var(--line); vertical-align: top; }
table.grid th { color: var(--ink-2); font-weight: 600; }
.table-wrap { overflow-x: auto; }
input.text {
  min-height: 48px; padding: 8px 12px; border-radius: 10px; border: 1px solid var(--line);
  background: var(--card); width: 100%; font-family: var(--font-de); font-size: 1.1rem;
}
input.text:focus { border-color: var(--blue); }
label.field { display: block; font-weight: 600; margin-bottom: 6px; }
.num, .stat b, .topic-card .n, .mrow > .muted, .topic-line > span:first-child, .gaprow .n, .cloze .g .n { font-family: var(--font-de); font-variant-numeric: tabular-nums; }
.kbd { font-size: .75rem; color: var(--ink-2); border: 1px solid var(--line); border-radius: 6px; padding: 0 6px; margin-right: 8px; }
.empty { text-align: center; color: var(--ink-2); padding: 24px 12px; }
.hidden { display: none !important; }
hr { border: 0; border-top: 1px solid var(--line); margin: 14px 0; }

/* ---------- home ---------- */
.hero { padding: 8px 0 18px; }
.hero h1 { font-size: 1.9rem; margin-bottom: .2rem; }
.stats { display: grid; grid-template-columns: repeat(3, 1fr); gap: 10px; }
.stat { background: var(--card); border: 1px solid var(--line); border-radius: 12px; padding: 12px; }
.stat b { display: block; font-size: 1.5rem; line-height: 1.1; }
.stat span { font-size: .85rem; color: var(--ink-2); }
.quick { display: grid; gap: 10px; }
@media (min-width: 600px) { .quick { grid-template-columns: 1fr 1fr; } }
.quick .btn { justify-content: flex-start; min-height: 60px; text-align: left; }
.quick .btn small { display: block; font-weight: 400; color: var(--ink-2); }
.btn.primary small { color: inherit; opacity: .85; }

/* ---------- learn ---------- */
.topics { display: grid; gap: 10px; }
@media (min-width: 600px) { .topics { grid-template-columns: 1fr 1fr; } }
.topic-card {
  display: grid; grid-template-columns: 40px 1fr; gap: 12px; align-items: start;
  text-align: left; background: var(--card); border: 1px solid var(--line); border-radius: 12px; padding: 12px 14px;
}
.topic-card:hover { border-color: var(--blue); }
.topic-card .n { font-family: var(--font-de); font-size: 1.3rem; color: var(--blue); line-height: 1.2; }
.topic-card b { display: block; }
.topic-card .tag { color: var(--ink-2); font-size: .9rem; }
.dots { display: flex; gap: 4px; margin-top: 6px; }
.dots i { width: 22px; height: 6px; border-radius: 3px; background: var(--line); display: block; }
.dots i.p { background: var(--blue); opacity: .5; }
.dots i.m { background: var(--green); }
.sheet .ex { display: grid; gap: 8px; }
.sheet .ex div { border-left: 3px solid var(--line); padding: 2px 12px; }
.sheet .ex .de { font-size: 1.1rem; }
.sheet .ex .en { color: var(--ink-2); font-size: .9rem; }
.sheet ul { padding-left: 1.2rem; margin: 0 0 .75rem; }
.sheet li { margin-bottom: .35rem; }

/* ---------- exercise ---------- */
.progress { display: flex; align-items: center; gap: 12px; margin-bottom: 12px; }
.progress .bar { flex: 1; }
.exercise .topic-line { color: var(--ink-2); font-size: .85rem; margin-bottom: 8px; display: flex; justify-content: space-between; gap: 8px; }
.exercise .instr { color: var(--ink-2); font-size: .95rem; margin-bottom: 8px; }
.exercise .prompt { font-family: var(--font-de); font-size: 1.35rem; line-height: 1.6; margin-bottom: 16px; }
.exercise .prompt .hint { font-family: var(--font-ui); color: var(--ink-2); font-size: .95rem; }
.gap {
  display: inline-block; min-width: 4ch; padding: 0 .3em; margin: 0 .1em;
  border-bottom: 3px solid var(--blue); background: var(--marker); border-radius: 3px 3px 0 0; line-height: 1.3;
}
.opts { display: grid; gap: 8px; }
.opt {
  text-align: left; min-height: 52px; padding: 10px 14px; border-radius: 12px; border: 1px solid var(--line);
  background: var(--card); font-family: var(--font-de); font-size: 1.15rem; display: flex; align-items: center; gap: 12px;
}
.opt .k { font-family: var(--font-ui); font-size: .8rem; color: var(--ink-2); border: 1px solid var(--line); border-radius: 6px; min-width: 24px; text-align: center; }
.opt:hover { border-color: var(--blue); }
.opt.sel { border-color: var(--blue); background: var(--blue-soft); }
.opt.ok { border-color: var(--green); background: var(--green-soft); }
.opt.bad { border-color: var(--red); background: var(--red-soft); }
.opt:disabled { cursor: default; }
.fill-row { display: flex; gap: 8px; align-items: stretch; }
.fill-row input { flex: 1; }
.words, .answer-line { display: flex; flex-wrap: wrap; gap: 8px; }
.answer-line { min-height: 60px; padding: 8px; border: 2px dashed var(--line); border-radius: 12px; margin-bottom: 12px; align-items: center; }
.answer-line.ok { border-color: var(--green); background: var(--green-soft); }
.answer-line.bad { border-color: var(--red); background: var(--red-soft); }
.tile {
  font-family: var(--font-de); font-size: 1.15rem; min-height: 46px; padding: 6px 14px; border-radius: 10px;
  border: 1px solid var(--line); background: var(--card); box-shadow: var(--shadow);
}
.tile:hover { border-color: var(--blue); }
.tile.ghost { visibility: hidden; }
.tile:disabled { cursor: default; }
.sentence { font-family: var(--font-de); font-size: 1.35rem; line-height: 1.9; }
.sentence .w {
  border: 0; background: none; padding: 2px 4px; border-radius: 6px; font: inherit; line-height: 1.3;
}
.sentence .w:hover { background: var(--blue-soft); }
.sentence .w.sel { background: var(--blue-soft); outline: 2px solid var(--blue); }
.sentence .w.strike { text-decoration: line-through; text-decoration-color: var(--red); text-decoration-thickness: 3px; color: var(--red); }
.sentence .w.missed { outline: 2px dashed var(--red); }
.sentence .ink { color: var(--blue); font-style: italic; margin-left: 4px; }
.feedback { border-radius: 12px; padding: 14px 16px; margin-top: 14px; border: 1px solid var(--line); }
.feedback.ok { border-color: var(--green); background: var(--green-soft); }
.feedback.bad { border-color: var(--red); background: var(--red-soft); }
.feedback .verdict { font-weight: 700; margin-bottom: 6px; }
.feedback .correct { font-family: var(--font-de); font-size: 1.15rem; }
.feedback .why { margin-top: 6px; }
.feedback .row { margin-top: 12px; }
.similar { margin-top: 12px; padding: 12px; border-radius: 10px; background: var(--card); border: 1px solid var(--line); }
.summary .big { font-size: 2.4rem; font-weight: 700; line-height: 1; }

/* ---------- exam ---------- */
.exam-head { display: flex; justify-content: space-between; align-items: center; gap: 8px; margin-bottom: 12px; }
.timer { font-variant-numeric: tabular-nums; font-weight: 700; padding: 6px 12px; border-radius: 10px; background: var(--card); border: 1px solid var(--line); }
.timer.low { color: var(--red); border-color: var(--red); }
.cloze { font-family: var(--font-de); font-size: 1.15rem; line-height: 1.9; white-space: pre-line; }
.cloze .g {
  display: inline-block; min-width: 3.2em; padding: 0 .4em; margin: 0 .1em; border-radius: 6px; line-height: 1.4;
  background: var(--marker); border-bottom: 3px solid var(--blue); font: inherit; cursor: pointer; text-align: center;
}
.cloze .g .n { font-family: var(--font-ui); font-size: .7rem; color: var(--ink-2); vertical-align: super; margin-right: 2px; }
.cloze .g.active { outline: 3px solid var(--blue); }
.cloze .g.ok { background: var(--green-soft); border-color: var(--green); }
.cloze .g.bad { background: var(--red-soft); border-color: var(--red); }
.gaprows { display: grid; gap: 8px; margin-top: 14px; }
.gaprow { display: grid; grid-template-columns: 2.2em 1fr; gap: 8px; align-items: center; }
.gaprow .n { font-weight: 700; color: var(--ink-2); }
.gaprow .abc { display: flex; gap: 6px; flex-wrap: wrap; }
.gaprow .abc button {
  min-height: 42px; padding: 4px 12px; border-radius: 10px; border: 1px solid var(--line); background: var(--card);
  font-family: var(--font-de); font-size: 1.05rem;
}
.gaprow .abc button.sel { background: var(--blue-soft); border-color: var(--blue); }
.gaprow .abc button.ok { background: var(--green-soft); border-color: var(--green); }
.gaprow .abc button.bad { background: var(--red-soft); border-color: var(--red); }
.bank { display: flex; flex-wrap: wrap; gap: 6px; margin-top: 14px; position: sticky; bottom: 76px; background: var(--card); padding: 8px; border-radius: 12px; border: 1px solid var(--line); box-shadow: var(--shadow); max-height: 34vh; overflow: auto; }
.bank .tile { font-size: 1rem; min-height: 40px; padding: 4px 10px; }
@media (min-width: 900px) { .bank { bottom: 12px; gap: 8px; padding: 10px; } .bank .tile { font-size: 1.1rem; min-height: 44px; } }
.bank .tile.used { opacity: .35; }
.parts { display: flex; gap: 6px; margin-bottom: 12px; flex-wrap: wrap; }
.exam-item { margin-bottom: 14px; }
.review-item { padding: 10px 0; border-bottom: 1px solid var(--line); }
.review-item .you { color: var(--red); }
.review-item .yes { color: var(--green); }

/* ---------- profile ---------- */
.mastery { display: grid; gap: 6px; }
.mrow { display: grid; grid-template-columns: 2em 1fr repeat(3, 56px); gap: 8px; align-items: center; font-size: .92rem; }
.mrow .t { white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.mrow .cell { height: 26px; border-radius: 6px; background: var(--line); position: relative; overflow: hidden; border: 0; padding: 0; }
.mrow .cell i { position: absolute; left: 0; top: 0; bottom: 0; background: var(--blue); opacity: .85; }
.mrow .cell.m i { background: var(--green); }
.mrow .cell span { position: absolute; inset: 0; display: grid; place-items: center; font-size: .75rem; color: var(--ink); }
.mhead { display: grid; grid-template-columns: 2em 1fr repeat(3, 56px); gap: 8px; font-size: .8rem; color: var(--ink-2); margin-bottom: 4px; }
.mhead span:nth-child(n+3) { text-align: center; }

/* ---------- drawer ---------- */
.drawer {
  position: fixed; inset: 0; z-index: 20; background: rgba(15, 20, 28, .45); display: none;
}
.drawer.open { display: block; }
.drawer .panel {
  position: absolute; right: 0; top: 0; bottom: 0; width: min(560px, 100%); background: var(--paper);
  overflow-y: auto; padding: 16px 16px 40px; box-shadow: -8px 0 30px rgba(0,0,0,.2);
}
.drawer .panel-head { display: flex; justify-content: space-between; align-items: center; gap: 8px; margin-bottom: 8px; position: sticky; top: -16px; background: var(--paper); padding: 8px 0; }
@media (prefers-reduced-motion: no-preference) {
  .drawer.open .panel { animation: slide .22s ease-out; }
  @keyframes slide { from { transform: translateX(24px); } to { transform: none; } }
}
.toast { position: fixed; left: 50%; bottom: 90px; transform: translateX(-50%); background: var(--ink); color: var(--paper); padding: 10px 16px; border-radius: 10px; z-index: 30; font-size: .95rem; }