:root {
  color-scheme: light;
  font-family: system-ui, -apple-system, "Segoe UI", sans-serif;
  color: var(--ink);
  background: #f0f0f0;
  scrollbar-gutter: stable;
  --ink: #191919;
  --muted: #444;
  --line: #aaa;
  --control-border: #818181;
  --paper: #fff;
  --selected: #e6e6e6;
  --graphite: #242424;
}

*, *::before, *::after { box-sizing: border-box; }
body { margin: 0; }
button, input { font: inherit; }
a { color: inherit; }
p, h1, h2, h3, h4 { margin: 0; }
[hidden] { display: none !important; }
:focus-visible { outline: 2px solid var(--ink); outline-offset: 4px; }
.sr-only { position: absolute; width: 1px; height: 1px; overflow: hidden; clip-path: inset(50%); white-space: nowrap; }

.shell { width: min(1040px, calc(100% - 3rem)); margin-inline: auto; }
.skip-link { position: absolute; top: -5rem; left: 1rem; z-index: 2; padding: .75rem; background: var(--paper); }
.skip-link:focus { top: .75rem; }
.site-header { background: var(--graphite); color: var(--paper); }
.site-header :focus-visible { outline-color: var(--paper); }
.header-inner, .site-footer { display: flex; justify-content: space-between; align-items: center; gap: 1rem; }
.header-inner { min-height: 55px; }
.brand { font-size: .94rem; font-weight: 750; text-decoration: none; }
.level, .section-kicker, .group-title, .progress-title {
  font-size: .73rem;
  font-weight: 750;
  letter-spacing: .09em;
  text-transform: uppercase;
}
.lesson-title { padding-block: 1.4rem .85rem; }
.section-kicker { color: var(--muted); margin-bottom: .45rem; }
h1 {
  font-family: Georgia, "Times New Roman", serif;
  font-weight: 400;
  line-height: 1;
  letter-spacing: -.035em;
}
h1 { font-size: clamp(2.7rem, 7vw, 4.5rem); }
#lesson { --card-scale: 1; }
#lesson.large-text { --card-scale: 1.22; }
.view-nav { display: flex; align-items: center; flex-wrap: wrap; gap: .35rem clamp(.65rem, 3vw, 1.7rem); border-bottom: 1px solid var(--line); }
.view-nav a {
  display: inline-flex; align-items: center; min-height: 43px; margin-bottom: -1px;
  border-bottom: 2px solid transparent; color: var(--muted); font-weight: 650; text-decoration: none;
}
.view-nav a[aria-current] { border-color: var(--ink); color: var(--ink); }
.view-nav a:hover { color: var(--ink); }
.view-nav .text-size { margin-inline-start: auto; min-height: 36px; padding-block: .3rem; }
.training-switch { display: flex; flex-wrap: wrap; gap: .65rem 1rem; margin-block: .4rem .8rem; }
.training-switch label { display: grid; gap: .28rem; font-size: calc(1rem * var(--card-scale)); font-weight: 650; max-width: 100%; }
.training-switch select { min-height: 43px; padding: .4rem .65rem; border: 1px solid var(--control-border); background: var(--paper); color: var(--ink); font: inherit; }

.lesson-layout { display: grid; grid-template-columns: minmax(0, 1fr) 210px; gap: clamp(1.3rem, 4vw, 3.5rem); }
.practice, .progress-panel, .study { padding-block: 1.45rem; }
.practice { min-width: 0; }
.practice h2, .question-task { font-size: calc(1.3rem * var(--card-scale)); font-weight: 650; line-height: 1.45; }
.question-task { margin-block: .75rem .5rem; }
.question-form { margin-top: .85rem; }
.question-sentence {
  padding: .7rem .85rem;
  border-inline-start: 2px solid var(--ink);
  background: var(--paper);
  font-size: calc(1.44rem * var(--card-scale));
  line-height: 1.48;
  overflow-wrap: anywhere;
}
.question-sentence + .question-sentence { margin-top: .65rem; }
.question-sentence:has(.gap) { line-height: 2.12; }
.choices { display: grid; gap: .45rem; border: 0; padding: 0; margin: .75rem 0 0; min-width: 0; }
.option {
  min-width: 0; min-height: 42px; padding: .42rem .7rem;
  border: 1px solid var(--control-border); background: var(--paper); color: var(--ink); cursor: pointer;
  font-size: calc(1.44rem * var(--card-scale)); line-height: 1.35;
  text-align: start; overflow-wrap: anywhere;
}
.option:hover:not(:disabled), .option.selected { border-color: var(--ink); background: var(--selected); }
.option.selected { box-shadow: inset 0 0 0 1px var(--ink); }
.option:disabled { cursor: default; }
.gap {
  color: var(--ink); width: 7.5rem; max-width: 100%; padding: .16rem .35rem;
  border: 1px solid var(--control-border); border-radius: 0; background: var(--paper); line-height: 1.5;
}
.gap:disabled { opacity: 1; }
.recall-input { width: 100%; }
.gap-correct { border-color: var(--ink); background: var(--selected); }
.gap-incorrect { border: 1px dashed var(--ink); }
.practice-hint { margin-top: .6rem; font-size: calc(1.06rem * var(--card-scale)); line-height: 1.45; }
.practice-hint summary { cursor: pointer; text-decoration: underline; }
.practice-hint p { margin-top: .3rem; }
.button {
  display: inline-flex; align-items: center; justify-content: center; min-height: 43px; padding: .48rem .9rem;
  border: 1px solid transparent; border-radius: 2px; text-decoration: none; text-align: center;
  cursor: pointer; font-weight: 650; font-size: .92rem; line-height: 1.35;
}
.primary { border-color: var(--graphite); background: var(--graphite); color: var(--paper); }
.primary:hover { background: var(--muted); }
.primary:disabled { opacity: .55; cursor: default; }
.secondary { border-color: var(--control-border); background: var(--paper); color: var(--ink); }
.secondary:hover { border-color: var(--ink); }
.question-form .button, .next { margin-top: .8rem; }
.practice .button, .group-practice { font-size: calc(1.06rem * var(--card-scale)); }
.group-practice { margin-bottom: .9rem; }
.actions { display: flex; flex-wrap: wrap; gap: .55rem; margin-top: .9rem; }
.feedback { margin-top: .9rem; padding: .75rem .85rem; background: var(--paper); border-inline-start: 2px solid var(--ink); }
.feedback.incorrect { border-inline-start-style: dashed; }
.feedback h3 { font-size: calc(1.15rem * var(--card-scale)); }
.feedback p { margin-top: .3rem; font-size: calc(1.18rem * var(--card-scale)); line-height: 1.5; }
.construction-comparison { margin: .6rem 0 0; padding-inline-start: 1.3rem; font-size: calc(1.08rem * var(--card-scale)); line-height: 1.5; }
.construction-comparison li + li { margin-top: .3rem; }
.construction-note, .feedback .construction-note { margin-top: .75rem; padding-top: .65rem; border-top: 1px solid var(--line); }
.solution { font-weight: 700; }

.progress-panel { border-inline-start: 1px solid var(--line); padding-inline-start: 1rem; }
.progress-count { margin-top: .35rem; font-variant-numeric: tabular-nums; font-size: 1.3rem; font-weight: 650; }
.progress-meter { accent-color: var(--ink); width: 100%; height: .52rem; }
.progress-detail, .progress-note { margin-top: .3rem; color: var(--muted); font-size: .86rem; }
.progress-panel .button { margin-top: .65rem; }
.section-description { margin-top: .55rem; color: var(--muted); line-height: 1.5; }
.study-heading h1 { font-size: clamp(2.5rem, 6vw, 3.75rem); }
.study > .section-kicker { font-size: .85rem; }
.group-switch { display: flex; flex-wrap: wrap; gap: .5rem; margin: 1.1rem 0 1.2rem; }
.family-switch { margin-block: .55rem .95rem; }
.group-button { border-color: var(--control-border); background: var(--paper); color: var(--ink); font-size: 1rem; }
.group-button:hover, .text-size:hover { border-color: var(--ink); }
.group-button[aria-pressed="true"] { border-color: var(--graphite); background: var(--graphite); color: var(--paper); }
.family-switch .group-button { font-size: calc(1.1rem * var(--card-scale)); }
.text-size[aria-pressed="true"] { border-color: var(--ink); background: var(--selected); }
.text-size { font-size: 1rem; }
.verb-grid { display: grid; gap: 1rem; }
.verb-row { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); column-gap: 1rem; }
.rektion-case + .rektion-case { margin-top: 1.5rem; }
.rektion-case > h2 { margin-bottom: .65rem; font-size: calc(1.25rem * var(--card-scale)); }
.irregular-group + .irregular-group { margin-top: 2rem; }
.pattern-title { margin-block: 1.2rem .65rem; font-size: calc(1.2rem * var(--card-scale)); }
.principal-forms { display: grid; grid-template-columns: minmax(6.5rem, 1fr) minmax(0, 1.6fr); gap: .35rem .7rem; margin-block: .8rem; line-height: 1.4; }
.principal-forms dt { font-size: calc(.98rem * var(--card-scale)); color: var(--muted); }
.principal-forms dd { margin: 0; font-size: calc(1.25rem * var(--card-scale)); overflow-wrap: anywhere; }
.principal-forms .principal-row-1 { grid-row: 1; }
.principal-forms .principal-row-2 { grid-row: 2; }
.principal-forms .principal-row-3 { grid-row: 3; }
.principal-forms .principal-row-4 { grid-row: 4; }
.principal-forms .principal-row-5 { grid-row: 5; }
.principal-question { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: .7rem; margin-top: .8rem; }
.principal-question label { display: grid; gap: .35rem; font-size: calc(1rem * var(--card-scale)); }
.principal-question .gap { width: 100%; min-width: 0; font-size: calc(1.44rem * var(--card-scale)); }
.verb-entry {
  min-width: 0; padding: clamp(1rem, 3vw, 1.6rem);
  border: 1px solid var(--line); border-top: 3px solid var(--ink); border-radius: 4px; background: var(--paper);
}
.verb-name { font-size: calc(2rem * var(--card-scale)); font-weight: 730; line-height: 1.1; overflow-wrap: anywhere; }
.verb-body { min-width: 0; }
.verb-sense { margin-top: .6rem; }
.verb-sense-highlight { padding: .7rem; border-inline-start: 3px solid var(--ink); background: var(--selected); }
.verb-sense + .verb-sense { margin-top: .95rem; padding-top: .8rem; border-top: 1px solid var(--line); }
.verb-more-senses > .verb-sense:first-child { margin-top: .95rem; padding-top: .8rem; border-top: 1px solid var(--line); }
.verb-supplement { margin-top: .95rem; padding-top: .8rem; border-top: 1px solid var(--line); }
.verb-supplement .meaning { margin-top: .35rem; }
.supplement-forms { margin-top: .35rem; font-size: calc(1.25rem * var(--card-scale)); font-weight: 650; line-height: 1.45; }
.form-comparison { margin: .6rem 0 0; padding: 0; list-style: none; font-size: calc(1.18rem * var(--card-scale)); line-height: 1.45; }
.form-comparison li + li { margin-top: .35rem; }
.verb-construction { font-size: calc(1.3rem * var(--card-scale)); font-weight: 700; line-height: 1.35; overflow-wrap: anywhere; }
.meaning { color: var(--muted); font-size: calc(1.18rem * var(--card-scale)); line-height: 1.35; }
.verb-forms { margin-top: .28rem; color: var(--muted); font-size: calc(1.06rem * var(--card-scale)); font-weight: 650; }
.example { margin-top: .6rem; font-size: calc(1.44rem * var(--card-scale)); line-height: 1.45; overflow-wrap: anywhere; }
.example strong { color: var(--ink); }
.translation { margin-top: .55rem; color: var(--muted); font-size: calc(1.03rem * var(--card-scale)); line-height: 1.5; }
.question-form > .translation { margin-bottom: .65rem; font-size: calc(1.15rem * var(--card-scale)); }
.translation summary { cursor: pointer; width: fit-content; text-decoration: underline; text-underline-offset: 2px; }
.translation p { margin-top: .28rem; font-size: calc(1.15rem * var(--card-scale)); }
.loading { padding-block: 1rem; }
.site-footer { padding-block: .95rem; color: var(--muted); font-size: .78rem; border-top: 1px solid var(--line); }

/* Each pair shares: title, shared forms, 11 first-sense tracks (including
   five principal-form rows), further senses, and note. Later pairs size independently. */
@supports (grid-template-rows: subgrid) {
  @media (min-width: 641px) {
    .verb-row { grid-template-rows: repeat(15, auto); }
    .verb-row > .verb-entry { display: grid; grid-row: 1 / -1; grid-template-rows: subgrid; row-gap: 0; }
    .verb-row > .verb-entry > .verb-name { grid-row: 1; }
    .verb-row > .verb-entry > .verb-forms { grid-row: 2; }
    .verb-row .verb-body { display: grid; grid-row: 3 / span 12; grid-template-rows: subgrid; row-gap: 0; }
    .verb-row .verb-body > .verb-sense:first-child { display: grid; grid-row: 1 / span 11; grid-template-rows: subgrid; row-gap: 0; }
    .verb-row .verb-body > .verb-sense:first-child > .verb-construction { grid-row: 1; }
    .verb-row .verb-body > .verb-sense:first-child > .verb-government { grid-row: 2; }
    .verb-row .verb-body > .verb-sense:first-child > .meaning { grid-row: 3; }
    .verb-row .verb-body > .verb-sense:first-child > .verb-forms:not(.verb-government) { grid-row: 4; }
    .verb-row .verb-body > .verb-sense:first-child > .principal-forms { grid-row: 5 / span 5; grid-template-rows: subgrid; row-gap: 0; }
    .verb-row .verb-body > .verb-sense:first-child > .principal-forms > :is(dt, dd) { padding-block: .175rem; }
    .verb-row .verb-body > .verb-sense:first-child > .example { grid-row: 10; }
    .verb-row .verb-body > .verb-sense:first-child > .translation { grid-row: 11; align-self: start; }
    .verb-row .verb-more-senses { grid-row: 12; }
    .verb-row > .verb-entry > .construction-note { grid-row: 15; align-self: start; }
  }
}

@media (max-width: 640px) {
  .shell { width: calc(100% - 1.5rem); }
  .lesson-layout { grid-template-columns: minmax(0, 1fr); gap: 0; }
  .practice, .progress-panel, .study { padding-block: 1rem; }
  .progress-panel { border-inline-start: 0; border-top: 1px solid var(--line); padding-inline-start: 0; }
  .progress-meter { max-width: 12rem; }
  .verb-row { grid-template-columns: minmax(0, 1fr); row-gap: 1rem; }
  .principal-question { grid-template-columns: minmax(0, 1fr); }
}

@media (max-width: 830px) {
  .large-text .verb-row { display: block; }
  .large-text .verb-row > .verb-entry + .verb-entry { margin-top: 1rem; }
  .large-text .verb-row > .verb-entry,
  .large-text .verb-row .verb-body,
  .large-text .verb-row .verb-body > .verb-sense:first-child { display: block; }
  .large-text .verb-row .verb-body > .verb-sense:first-child > .principal-forms { grid-template-rows: none; row-gap: .35rem; }
  .large-text .verb-row .verb-body > .verb-sense:first-child > .principal-forms > :is(dt, dd) { padding-block: 0; }
}