/*
 * Plain CSS, no build step. Every file in app/assets/stylesheets is included
 * by the layout. Components use BEM-style names: .block__element--modifier.
 */

:root {
  --color-ink: #1d2a24;
  --color-ink-muted: #5b6b63;
  --color-paper: #fbf8f1;
  --color-surface: #ffffff;
  --color-border: #e2ddd0;
  --color-accent: #16794c;
  --color-accent-strong: #0f5c39;
  --color-accent-soft: #e2f3e9;
  --color-warning: #b45309;
  --color-warning-soft: #fdf0dc;
  --color-danger: #b42318;
  --color-danger-soft: #fde8e6;

  --radius: 0.75rem;
  --shadow: 0 1px 2px rgb(0 0 0 / 0.06), 0 4px 16px rgb(0 0 0 / 0.05);
  --space: 1rem;
  --font-body: system-ui, "Segoe UI", sans-serif;

  color-scheme: light;
}

*, *::before, *::after { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--color-paper);
  color: var(--color-ink);
  font-family: var(--font-body);
  font-size: 1.0625rem;
  line-height: 1.5;
}

h1, h2, h3 { line-height: 1.2; margin-block: 0 0.5em; }
h1 { font-size: clamp(1.6rem, 4vw, 2.2rem); }
h1 small, h2 small { color: var(--color-ink-muted); font-size: 0.6em; font-weight: 500; }

a { color: var(--color-accent-strong); }
a:hover { color: var(--color-accent); }

:focus-visible { outline: 3px solid var(--color-accent); outline-offset: 2px; }

/* Layout */

.site-header {
  align-items: center;
  background: var(--color-surface);
  border-block-end: 1px solid var(--color-border);
  display: flex;
  flex-wrap: wrap;
  gap: var(--space);
  padding: 0.75rem clamp(1rem, 4vw, 2rem);

  form { margin: 0; }
}

.site-header__brand {
  color: var(--color-accent-strong);
  font-size: 1.25rem;
  font-weight: 800;
  text-decoration: none;

  &::before { content: "♞ "; }
}

.site-header__nav {
  display: flex;
  flex: 1;
  flex-wrap: wrap;
  gap: 0.25rem 1rem;

  a { font-weight: 600; text-decoration: none; }
}

.site-header__actions { align-items: center; display: flex; gap: 0.75rem; }
.site-header__user { color: var(--color-ink-muted); font-size: 0.9rem; }

.page {
  margin-inline: auto;
  max-width: 72rem;
  padding: clamp(1rem, 4vw, 2rem);
}

.page-header {
  align-items: center;
  display: flex;
  flex-wrap: wrap;
  gap: var(--space);
  justify-content: space-between;
  margin-block-end: var(--space);

  h1, h2 { margin: 0; }
}

.page-header__actions { display: flex; flex-wrap: wrap; gap: 0.5rem; }
.page-header__actions form { margin: 0; }

.breadcrumbs {
  font-size: 0.9rem;
  margin-block-end: 0.5rem;

  a::before { content: "← "; }
}

.lede { color: var(--color-ink-muted); font-size: 1.1rem; }
.empty { color: var(--color-ink-muted); font-style: italic; }
.hint { color: var(--color-ink-muted); display: block; font-size: 0.85rem; }
.plain-list { list-style: none; padding: 0; }

/* Components */

.btn {
  align-items: center;
  background: var(--color-accent);
  border: 2px solid var(--color-accent);
  border-radius: 999px;
  color: white;
  cursor: pointer;
  display: inline-flex;
  font: inherit;
  font-weight: 700;
  gap: 0.4em;
  padding: 0.45em 1.1em;
  text-decoration: none;

  &:hover { background: var(--color-accent-strong); border-color: var(--color-accent-strong); color: white; }
}

.btn--plain {
  background: transparent;
  color: var(--color-accent-strong);

  &:hover { background: var(--color-accent-soft); color: var(--color-accent-strong); }
}

.btn--danger {
  background: transparent;
  border-color: var(--color-danger);
  color: var(--color-danger);

  &:hover { background: var(--color-danger-soft); border-color: var(--color-danger); color: var(--color-danger); }
}

.btn--small { font-size: 0.85rem; padding: 0.25em 0.8em; }
.btn--icon { font-size: 1.1rem; justify-content: center; min-width: 3rem; padding: 0.4em 0.6em; }

.badge {
  background: var(--color-border);
  border-radius: 999px;
  display: inline-block;
  font-size: 0.8rem;
  font-weight: 700;
  padding: 0.1em 0.7em;
  vertical-align: middle;
}

.badge--done { background: var(--color-accent-soft); color: var(--color-accent-strong); }
.badge--done::before { content: "✓ "; }
.badge--warning { background: var(--color-warning-soft); color: var(--color-warning); }

.card {
  background: var(--color-surface);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  margin-inline: auto;
  max-width: 44rem;
  padding: clamp(1.25rem, 4vw, 2rem);
}

.card--narrow { max-width: 28rem; }

.flash {
  border-radius: var(--radius);
  font-weight: 600;
  margin-block-end: var(--space);
  padding: 0.75rem 1rem;
}

.flash--notice { background: var(--color-accent-soft); color: var(--color-accent-strong); }
.flash--alert { background: var(--color-danger-soft); color: var(--color-danger); }

.locale-switcher {
  border: 1px solid var(--color-border);
  border-radius: 999px;
  display: flex;
  overflow: hidden;

  form { display: contents; }
}

.locale-switcher__option {
  background: transparent;
  border: 0;
  color: var(--color-ink-muted);
  cursor: pointer;
  font: inherit;
  font-size: 0.85rem;
  padding: 0.2em 0.8em;

  &:hover { background: var(--color-accent-soft); }
}

.locale-switcher__option--current {
  background: var(--color-accent);
  color: white;
  cursor: default;

  &:hover { background: var(--color-accent); }
}

/* Forms */

.form { display: grid; gap: var(--space); }

.field {
  display: grid;
  gap: 0.3rem;

  label { font-weight: 700; }

  input:not([type="file"]), select, textarea {
    background: var(--color-surface);
    border: 2px solid var(--color-border);
    border-radius: 0.5rem;
    font: inherit;
    padding: 0.5em 0.7em;
    width: 100%;

    &:focus { border-color: var(--color-accent); outline: none; }
  }
}

.form .btn { justify-self: start; }

.form-errors {
  background: var(--color-danger-soft);
  border-radius: var(--radius);
  color: var(--color-danger);
  padding: 0.75rem 1rem;

  h2 { font-size: 1rem; }
  ul { margin: 0; padding-inline-start: 1.2rem; }
}

/* Tables */

.table {
  background: var(--color-surface);
  border-collapse: collapse;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  overflow: hidden;
  width: 100%;

  th, td { border-block-end: 1px solid var(--color-border); padding: 0.7rem 1rem; text-align: start; }
  th { background: var(--color-accent-soft); font-size: 0.85rem; text-transform: uppercase; letter-spacing: 0.03em; }
  tr:last-child td { border-block-end: 0; }
}

meter { inline-size: 6rem; vertical-align: middle; }

/* Lessons */

.lesson-list {
  display: grid;
  gap: var(--space);
  grid-template-columns: repeat(auto-fill, minmax(16rem, 1fr));
  list-style: none;
  padding: 0;
}

.lesson-card {
  background: var(--color-surface);
  border: 2px solid transparent;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  color: inherit;
  display: grid;
  gap: 0.5rem;
  height: 100%;
  padding: 1.25rem;
  text-decoration: none;
  transition: border-color 120ms, transform 120ms;

  &:hover { border-color: var(--color-accent); color: inherit; transform: translateY(-2px); }
}

.lesson-card__title { font-size: 1.25rem; margin: 0; }
.lesson-card__description { color: var(--color-ink-muted); margin: 0; }
.lesson-card__progress { align-self: end; color: var(--color-ink-muted); font-size: 0.9rem; margin: 0; }

.game-list {
  display: grid;
  gap: 0.5rem;
  padding: 0;
  list-style: none;
  counter-reset: games;
}

.game-list__link {
  align-items: center;
  background: var(--color-surface);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  color: inherit;
  counter-increment: games;
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 1rem;
  padding: 0.9rem 1.1rem;
  text-decoration: none;

  &::before {
    background: var(--color-accent-soft);
    border-radius: 999px;
    color: var(--color-accent-strong);
    content: counter(games);
    display: grid;
    font-weight: 800;
    height: 2rem;
    place-items: center;
    width: 2rem;
  }

  &:hover { color: inherit; outline: 2px solid var(--color-accent); }
}

.game-list__title { font-weight: 700; }
.game-list__meta { color: var(--color-ink-muted); flex: 1; font-size: 0.9rem; }

.pager { display: flex; gap: 0.5rem; justify-content: space-between; margin-block-start: 2rem; }

/* Videos */

.videos {
  margin-block-start: 2rem;

  .video { margin: 0 0 var(--space); }
  video { border-radius: var(--radius); background: black; max-width: 100%; width: 40rem; }
  figcaption { color: var(--color-ink-muted); font-weight: 600; }
}

/* Teacher progress */

.progress-lesson { margin-block-end: 1.5rem; }

.progress-games {
  display: grid;
  gap: 0.35rem;
  padding-inline-start: 1.5rem;

  li { align-items: center; display: flex; flex-wrap: wrap; gap: 0.5rem; }
  small { color: var(--color-ink-muted); }
}

/* Admin */

.admin-games {
  display: grid;
  gap: 0.75rem;
  padding: 0;
  list-style: none;
}

.admin-games__game {
  background: var(--color-surface);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 1rem 1.25rem;
}

.admin-games__heading { align-items: baseline; display: flex; flex-wrap: wrap; gap: 0.5rem 1rem; }

.admin-videos {
  list-style: none;
  padding: 0;

  form { margin: 0; }
}

.admin-videos__video { align-items: center; display: flex; gap: 1rem; padding-block: 0.25rem; }

.fieldset {
  border: 0;
  display: grid;
  gap: var(--space);
  margin: 0;
  padding: 0;

  legend { font-size: 1.1rem; font-weight: 800; margin-block-end: 0.5rem; padding: 0; }
}

.filters {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-block-end: var(--space);
}

.filters__option {
  border: 2px solid var(--color-border);
  border-radius: 999px;
  font-weight: 600;
  padding: 0.15em 0.9em;
  text-decoration: none;
}

.filters__option--current { background: var(--color-accent); border-color: var(--color-accent); color: white; }
.filters__option--current:hover { color: white; }

[hidden] { display: none !important; }

.table__actions {
  display: flex;
  gap: 0.5rem;
  justify-content: end;

  form { margin: 0; }
}

.visually-hidden {
  clip-path: inset(50%);
  height: 1px;
  overflow: hidden;
  position: absolute;
  white-space: nowrap;
  width: 1px;
}

/* Puzzles */

.puzzle-list {
  display: grid;
  gap: var(--space);
  grid-template-columns: repeat(auto-fill, minmax(14rem, 1fr));
  list-style: none;
  padding: 0;
}

.puzzle-card {
  background: var(--color-surface);
  border: 2px solid transparent;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  color: inherit;
  display: grid;
  gap: 0.4rem;
  height: 100%;
  padding: 1.1rem;
  text-decoration: none;

  &:hover { border-color: var(--color-accent); color: inherit; }
}

.puzzle-card__title { font-size: 1.15rem; margin: 0; }

.puzzle-details { align-items: center; display: flex; flex-wrap: wrap; gap: 0.5rem; margin: 0 0 0.5rem; }
.puzzle-details__opening { color: var(--color-ink-muted); font-style: italic; }

.badge--easy { background: var(--color-accent-soft); color: var(--color-accent-strong); }
.badge--medium { background: var(--color-warning-soft); color: var(--color-warning); }
.badge--hard { background: var(--color-danger-soft); color: var(--color-danger); }

.puzzle-result {
  background: var(--color-accent-soft);
  border-radius: var(--radius);
  margin-block-start: 1.5rem;
  padding: 1rem 1.25rem;

  h2 { color: var(--color-accent-strong); }
}

.field-row { display: grid; gap: var(--space); grid-template-columns: repeat(auto-fit, minmax(10rem, 1fr)); }
.choices { display: flex; flex-wrap: wrap; gap: 0.5rem 1.5rem; }
.choice { align-items: center; display: flex; font-weight: 600; gap: 0.4rem; }
.monospace { font-family: ui-monospace, "SF Mono", Menlo, monospace; }

/* Sortable lists */

.sortable__handle {
  background: none;
  border: 0;
  border-radius: 0.3rem;
  color: var(--color-ink-muted);
  cursor: grab;
  font: inherit;
  font-weight: 800;
  letter-spacing: -0.15em;
  padding: 0.1em 0.45em 0.1em 0.3em;
  touch-action: none;
  user-select: none;

  &:hover, &:focus-visible { background: var(--color-accent-soft); color: var(--color-accent-strong); }
  &:active { cursor: grabbing; }
}

.sortable__item--dragging {
  box-shadow: 0 8px 24px rgb(0 0 0 / 0.18);
  outline: 2px solid var(--color-accent);
  position: relative;
  z-index: 1;
}