/* Rolang — a workbook you can write in.
   The look borrows from the printed book: generous line height, a paper-toned
   surface, and answers written on visible rules. */

:root {
  --paper: #fbfaf7;
  --surface: #ffffff;
  --ink: #1d1c1a;
  --ink-soft: #5c5a55;
  --ink-faint: #8d8a83;
  --rule: #e2ded4;
  --rule-strong: #cec8ba;
  --accent: #146b5c;
  --accent-soft: #e3f1ec;
  --ok: #1c7a4a;
  --bad: #b4402c;
  --warn: #a86a12;
  --flag: #8a5cc4;
  --radius: 10px;
  --font: ui-sans-serif, -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --serif: "Iowan Old Style", "Palatino Linotype", Palatino, Georgia, serif;
}

@media (prefers-color-scheme: dark) {
  :root {
    --paper: #16181a;
    --surface: #1e2124;
    --ink: #e9e6e0;
    --ink-soft: #a9a59d;
    --ink-faint: #7d7a74;
    --rule: #32363a;
    --rule-strong: #464b50;
    --accent: #4bbfa5;
    --accent-soft: #14322c;
    --ok: #55c98a;
    --bad: #f0836a;
    --warn: #dfa645;
    --flag: #b394e6;
  }
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.6;
  -webkit-text-size-adjust: 100%;
}

a { color: var(--accent); text-decoration-thickness: 1px; text-underline-offset: 2px; }

/* ---------- layout ---------- */

.wrap { max-width: 62rem; margin: 0 auto; padding: 1.5rem 1.25rem 4rem; }
.wrap.narrow { max-width: 26rem; padding-top: 4rem; }
.section { margin: 2.5rem 0; }
.row { display: flex; gap: .6rem; align-items: center; flex-wrap: wrap; }
.stack { display: grid; gap: .9rem; }
.spacer { flex: 1; }

h1 { font-size: 1.7rem; line-height: 1.25; margin: 0 0 .3rem; letter-spacing: -.01em; }
h1 small { font-weight: 400; color: var(--ink-soft); font-size: .62em; display: block; margin-top: .25rem; }
h2 { font-size: 1.15rem; margin: 0 0 .3rem; }
h3 { font-size: 1rem; margin: 0; }
.subtitle { color: var(--ink-soft); margin: 0 0 1.2rem; }
.hint { color: var(--ink-faint); font-size: .875rem; margin: .3rem 0; }

/* ---------- top bar ---------- */

.topbar {
  display: flex; align-items: center; gap: 1.2rem;
  padding: .7rem 1.25rem;
  border-bottom: 1px solid var(--rule);
  background: var(--surface);
  position: sticky; top: 0; z-index: 20;
  flex-wrap: wrap;
}
.brand { font-weight: 700; letter-spacing: -.01em; text-decoration: none; color: var(--ink); }
.topbar nav { display: flex; gap: 1rem; }
.topbar nav a { color: var(--ink-soft); text-decoration: none; font-size: .93rem; }
.topbar nav a:hover { color: var(--ink); }
.topbar nav a[aria-current="page"] { color: var(--accent); font-weight: 600; }
.topbar-end { margin-left: auto; display: flex; align-items: center; gap: .8rem; }
.who { color: var(--ink-faint); font-size: .85rem; }
.foot { border-top: 1px solid var(--rule); padding: 1.2rem 1.25rem; }
.foot p { max-width: 62rem; margin: 0 auto; color: var(--ink-faint); font-size: .78rem; }

/* ---------- controls ---------- */

button, .button {
  font: inherit; font-size: .9rem;
  border: 1px solid var(--rule-strong);
  background: var(--surface); color: var(--ink);
  border-radius: 8px; padding: .4rem .8rem; cursor: pointer;
  text-decoration: none; display: inline-block;
  transition: background .12s, border-color .12s, color .12s;
}
button:hover, .button:hover { border-color: var(--accent); color: var(--accent); }
button.primary, .primary {
  background: var(--accent); border-color: var(--accent); color: #fff; font-weight: 600;
}
button.primary:hover { filter: brightness(1.08); color: #fff; }
button.link {
  border: none; background: none; color: var(--ink-soft); padding: 0;
  font-size: .85rem; text-decoration: underline;
}
button.link:hover { color: var(--accent); }

input[type="email"], input[type="password"] {
  font: inherit; width: 100%; padding: .5rem .6rem;
  border: 1px solid var(--rule-strong); border-radius: 8px;
  background: var(--paper); color: var(--ink);
}
label { display: grid; gap: .3rem; font-size: .9rem; color: var(--ink-soft); }

.card {
  background: var(--surface); border: 1px solid var(--rule);
  border-radius: var(--radius); padding: 1.5rem;
}
.card.login h1 { margin-bottom: .1rem; }
.card.empty { text-align: center; color: var(--ink-soft); }
.alert {
  background: color-mix(in srgb, var(--bad) 12%, transparent);
  border: 1px solid color-mix(in srgb, var(--bad) 40%, transparent);
  color: var(--bad); padding: .6rem .8rem; border-radius: 8px; font-size: .9rem;
}

/* ---------- unit grid ---------- */

.unit-grid {
  list-style: none; padding: 0; margin: 0;
  display: grid; gap: .7rem;
  grid-template-columns: repeat(auto-fill, minmax(15rem, 1fr));
}
.unit-card {
  display: grid; gap: .3rem; text-decoration: none; color: inherit;
  background: var(--surface); border: 1px solid var(--rule);
  border-radius: var(--radius); padding: .8rem .9rem;
  transition: border-color .12s, transform .12s;
}
.unit-card:hover { border-color: var(--accent); transform: translateY(-1px); }
.unit-id { font-size: .74rem; text-transform: uppercase; letter-spacing: .06em; color: var(--accent); font-weight: 700; }
.unit-title { font-weight: 600; line-height: 1.3; }
.unit-meta { font-size: .78rem; color: var(--ink-faint); }
.bar { display: block; height: 4px; border-radius: 99px; background: var(--rule); overflow: hidden; margin: .25rem 0 .1rem; }
.bar-fill { display: block; height: 100%; background: var(--accent); border-radius: 99px; }

/* ---------- unit page ---------- */

.crumbs { font-size: .85rem; color: var(--ink-faint); margin-bottom: .8rem; }
.crumbs span { margin: 0 .35rem; }
.unit-head { margin-bottom: 1.5rem; }

.passage {
  background: var(--surface); border: 1px solid var(--rule);
  border-radius: var(--radius); padding: .8rem 1rem; margin-bottom: 1.5rem;
}
.passage summary { cursor: pointer; font-weight: 600; }
.passage-body { font-family: var(--serif); font-size: 1.02rem; line-height: 1.75; }
.passage-body p { margin: .8rem 0; }
.passage-body .hint { font-family: var(--font); }

.exercises { display: grid; gap: 1.1rem; }

.ex {
  background: var(--surface); border: 1px solid var(--rule);
  border-radius: var(--radius); padding: 1.1rem 1.2rem;
  scroll-margin-top: 5rem;
}
.ex.is-marked { border-left: 3px solid var(--rule-strong); }
.ex[data-status="correct"] { border-left-color: var(--ok); }
.ex[data-status="partial"] { border-left-color: var(--warn); }
.ex[data-status="incorrect"] { border-left-color: var(--bad); }
.ex:target { box-shadow: 0 0 0 3px var(--accent-soft); border-color: var(--accent); }

.ex-head-row { display: flex; align-items: center; gap: .6rem; margin-bottom: .5rem; }
.ex-head h3 { color: var(--accent); font-size: .8rem; text-transform: uppercase; letter-spacing: .06em; }
.ex .ro { font-weight: 600; margin: 0; line-height: 1.45; }
.ex .en { font-style: italic; color: var(--ink-soft); margin: .15rem 0 0; font-size: .9rem; }

.pill {
  font-size: .7rem; text-transform: uppercase; letter-spacing: .05em;
  border-radius: 99px; padding: .1rem .5rem; border: 1px solid var(--rule-strong);
  color: var(--ink-faint);
}
.pill-correct { color: var(--ok); border-color: var(--ok); }
.pill-partial { color: var(--warn); border-color: var(--warn); }
.pill-incorrect { color: var(--bad); border-color: var(--bad); }
.badge {
  font-size: .7rem; color: var(--ink-faint); border: 1px solid var(--rule);
  border-radius: 99px; padding: .1rem .5rem;
}

/* CEFR band badge. A1 -> C1 warms from green to violet so the level reads at a
   glance without needing the text. */
.level {
  display: inline-block; font-size: .68rem; font-weight: 700;
  letter-spacing: .05em; border-radius: 5px; padding: .1rem .35rem;
  color: #fff; vertical-align: middle;
}
.level-A1 { background: #2f8f6b; }
.level-A2 { background: #3d7fa8; }
.level-B1 { background: #9a7215; }
.level-B2 { background: #a85a2c; }
.level-C1 { background: #7a52b3; }

h2 .count {
  font-size: .78rem; font-weight: 400; color: var(--ink-faint);
  letter-spacing: 0; margin-left: .4rem;
}
h1 .level { font-size: .8rem; margin-right: .3rem; }
h1 small .en { font-style: italic; }

.flag-btn { font-size: .78rem; padding: .2rem .55rem; color: var(--ink-faint); }
.flag-btn.on { color: var(--flag); border-color: var(--flag); background: color-mix(in srgb, var(--flag) 10%, transparent); }
@media (max-width: 34rem) { .flag-text { display: none; } }

/* audio */
.audio { display: flex; align-items: center; gap: .6rem; margin-top: .7rem; flex-wrap: wrap; }
.audio audio { height: 2rem; max-width: 22rem; flex: 1 1 16rem; }
.rates { display: inline-flex; gap: .2rem; }
.rates button { font-size: .72rem; padding: .15rem .4rem; }
.rates button.on { background: var(--accent-soft); border-color: var(--accent); color: var(--accent); }
.cue { font-size: .7rem; color: var(--ink-faint); }

/* ---------- items ---------- */

.items { margin: 1rem 0 .3rem; display: grid; gap: .45rem; }
.item { margin: 0; line-height: 2.1; }
.note { margin: 0; color: var(--ink-soft); font-size: .93rem; }
.item-label {
  font-size: .72rem; text-transform: uppercase; letter-spacing: .05em;
  color: var(--ink-faint); display: block;
}
.stem { margin: 0 0 .2rem; }

.blank {
  font: inherit; color: var(--ink);
  border: none; border-bottom: 1.5px solid var(--rule-strong);
  background: transparent; padding: 0 .25rem 1px;
  min-width: 8rem; max-width: 100%;
  transition: border-color .12s, background .12s;
}
.blank:focus { outline: none; border-bottom-color: var(--accent); background: var(--accent-soft); }
.blank.wide { min-width: 18rem; }
.blank.is-correct { border-bottom-color: var(--ok); }
.blank.is-wrong { border-bottom-color: var(--bad); background: color-mix(in srgb, var(--bad) 8%, transparent); }

textarea.write {
  font: inherit; width: 100%; color: var(--ink);
  background: transparent; border: 1px solid var(--rule);
  border-radius: 8px; padding: .45rem .6rem; resize: vertical; line-height: 1.6;
}
textarea.write:focus { outline: none; border-color: var(--accent); }
textarea.write.is-correct { border-color: var(--ok); }
textarea.write.is-wrong { border-color: var(--bad); }

.options { list-style: none; padding: 0; margin: .2rem 0 0; display: grid; gap: .15rem; }
.options label { display: flex; gap: .45rem; align-items: baseline; color: var(--ink); cursor: pointer; font-size: 1rem; }
.options .letter { color: var(--ink-faint); font-variant-numeric: tabular-nums; }
.options.is-correct label { color: var(--ok); }
.options.is-wrong label { color: var(--bad); }

.chips { display: inline-flex; gap: .2rem; vertical-align: baseline; }
.chip {
  border-radius: 99px; padding: .05rem .6rem; font-size: .93rem;
  border-color: var(--rule-strong); color: var(--ink-soft);
}
.chip.on { background: var(--accent); border-color: var(--accent); color: #fff; font-weight: 600; }
.chips.is-correct .chip.on { background: var(--ok); border-color: var(--ok); }
.chips.is-wrong .chip.on { background: var(--bad); border-color: var(--bad); }

/* ---------- reveal & marks ---------- */

.ex-foot { border-top: 1px dashed var(--rule); margin-top: .9rem; padding-top: .8rem; }
.saved { font-size: .75rem; color: var(--ink-faint); }
.key { margin-top: .9rem; background: var(--paper); border: 1px solid var(--rule); border-radius: 8px; padding: .8rem .9rem; }
.key-label {
  margin: 0 0 .3rem; font-size: .72rem; text-transform: uppercase;
  letter-spacing: .06em; color: var(--accent); font-weight: 700;
  display: flex; justify-content: space-between; gap: 1rem;
}
.book-ref { color: var(--ink-faint); font-weight: 400; text-transform: none; letter-spacing: 0; }
.key-body { margin: 0; line-height: 1.7; }
.autocheck { font-size: .8rem; color: var(--ink-faint); margin: .5rem 0 0; }
.autocheck .mode {
  border-bottom: 1px dotted currentColor; cursor: help;
  font-variant: small-caps; letter-spacing: .03em;
}
.ok { color: var(--ok); }
.bad { color: var(--bad); }
.flag { color: var(--flag); }

.marks { display: flex; gap: .4rem; align-items: center; margin-top: .7rem; flex-wrap: wrap; }
.marks-label { font-size: .8rem; color: var(--ink-soft); margin-right: .2rem; }
.mark.on { background: var(--accent); border-color: var(--accent); color: #fff; font-weight: 600; }
.mark[data-status="correct"].on { background: var(--ok); border-color: var(--ok); }
.mark[data-status="partial"].on { background: var(--warn); border-color: var(--warn); }
.mark[data-status="incorrect"].on { background: var(--bad); border-color: var(--bad); }
.mark.clear { color: var(--ink-faint); }
.mark.suggested { border-color: var(--accent); box-shadow: 0 0 0 2px var(--accent-soft); }

.pager { display: flex; justify-content: space-between; margin-top: 2rem; gap: 1rem; }

/* ---------- review list ---------- */

.review-list { list-style: none; padding: 0; margin: 0; display: grid; gap: .6rem; }
.review-list a {
  display: grid; gap: .25rem; text-decoration: none; color: inherit;
  background: var(--surface); border: 1px solid var(--rule);
  border-left: 3px solid var(--flag);
  border-radius: var(--radius); padding: .8rem .9rem;
}
.review-list a:hover { border-color: var(--accent); }
.review-unit { font-size: .74rem; text-transform: uppercase; letter-spacing: .06em; color: var(--flag); font-weight: 700; }
.review-instruction { font-weight: 500; }
.review-meta { display: flex; gap: .4rem; align-items: center; flex-wrap: wrap; margin-top: .2rem; }

/* ---------- progress ---------- */

.tiles {
  list-style: none; padding: 0; margin: 1.5rem 0;
  display: grid; gap: .7rem; grid-template-columns: repeat(auto-fill, minmax(9rem, 1fr));
}
.tile {
  background: var(--surface); border: 1px solid var(--rule);
  border-radius: var(--radius); padding: .9rem;
  display: grid; gap: .1rem;
}
.tile-n { font-size: 1.7rem; font-weight: 700; line-height: 1.1; font-variant-numeric: tabular-nums; }
.tile-l { font-size: .8rem; color: var(--ink-soft); }
.tile-sub { font-size: .72rem; color: var(--ink-faint); }

.table-scroll { overflow-x: auto; }
.grid { width: 100%; border-collapse: collapse; font-size: .88rem; }
.grid th, .grid td { text-align: left; padding: .4rem .6rem; border-bottom: 1px solid var(--rule); white-space: nowrap; }
.grid th { font-size: .72rem; text-transform: uppercase; letter-spacing: .05em; color: var(--ink-faint); font-weight: 600; }
.grid td.t-title { white-space: normal; color: var(--ink-soft); }
.grid tr.untouched td { color: var(--ink-faint); }
.grid tbody tr:hover { background: var(--paper); }

/* ---------- phones ---------- */

@media (max-width: 34rem) {
  .wrap { padding: 1rem .85rem 3rem; }
  .topbar { gap: .7rem; padding: .6rem .85rem; }
  .topbar nav { gap: .8rem; order: 3; width: 100%; }
  .topbar-end { gap: .6rem; }
  .who { max-width: 8rem; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }

  h1 { font-size: 1.4rem; }
  .ex { padding: .9rem .85rem; }

  /* A shorter rule keeps the sentence's trailing words on the same line. */
  .blank { min-width: 5rem; }
  .blank.wide { min-width: 0; width: 100%; }
  .item { line-height: 2.4; }

  /* Stack the verdict buttons rather than letting them squeeze. */
  .marks { gap: .35rem; }
  .marks-label { width: 100%; margin-bottom: .1rem; }
  .audio audio { flex-basis: 100%; max-width: none; }
}