:root {
  --bg: #f4f5f7;
  --card: #ffffff;
  --text: #1c1e21;
  --muted: #65676b;
  --line: #dfe1e5;
  --accent: #1f4e79;
  --ok: #2e7d32;
  --bad: #c62828;
  --m: #1e6fd9;
  --f: #d32f2f;
  --n: #2b9348;
  --radius: 14px;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #121417; --card: #1d2025; --text: #e8eaed; --muted: #9aa0a6;
    --line: #2f333a; --accent: #6ea8fe; --ok: #66bb6a; --bad: #ef5350;
  }
}
* { box-sizing: border-box; }
html, body { margin: 0; }
body {
  background: var(--bg); color: var(--text);
  font: 16px/1.45 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  padding-bottom: calc(64px + env(safe-area-inset-bottom));
}
button { font: inherit; color: inherit; cursor: pointer; }

.top { position: sticky; top: 0; z-index: 2; background: var(--accent); color: #fff; padding: 12px 16px; }
.top h1 { margin: 0; font-size: 1.15rem; max-width: 960px; margin-inline: auto; display: flex; align-items: center; gap: 8px; }
.badge { font-size: .75rem; background: rgba(255,255,255,.2); padding: 2px 8px; border-radius: 999px; }

main { max-width: 960px; margin: 0 auto; padding: 16px; }

.tabs {
  position: fixed; bottom: 0; left: 0; right: 0; z-index: 2;
  display: grid; grid-template-columns: repeat(4, 1fr);
  background: var(--card); border-top: 1px solid var(--line);
  padding-bottom: env(safe-area-inset-bottom);
}
.tabs button { background: none; border: 0; padding: 14px 4px; color: var(--muted); font-size: .9rem; }
.tabs button.active { color: var(--accent); font-weight: 600; box-shadow: inset 0 3px 0 var(--accent); }

.toolbar { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; margin-bottom: 14px; }
.toolbar select, .toolbar input {
  font: inherit; padding: 8px 10px; border-radius: 10px; border: 1px solid var(--line);
  background: var(--card); color: var(--text); min-width: 0;
}
.toolbar input { flex: 1 1 160px; }
.count { color: var(--muted); font-size: .9rem; margin-left: auto; }

.grid { display: grid; gap: 12px; grid-template-columns: repeat(auto-fill, minmax(260px, 1fr)); }

.card {
  background: var(--card); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 16px; border-left: 5px solid var(--line); display: flex; flex-direction: column; gap: 8px;
}
.card.g-m { border-left-color: var(--m); }
.card.g-f { border-left-color: var(--f); }
.card.g-n, .card.g-npl { border-left-color: var(--n); }
.card .face { background: none; border: 0; padding: 0; text-align: left; display: flex; flex-direction: column; gap: 6px; }
.card .word { font-size: 1.5rem; font-weight: 600; }
.card .meta { font-size: .75rem; color: var(--muted); text-transform: uppercase; letter-spacing: .04em; }
.card .ex { color: var(--muted); font-style: italic; }
.card .tr { border-top: 1px dashed var(--line); padding-top: 8px; display: none; }
.card.open .tr { display: block; }
.card .tr p { margin: 2px 0; }
.card .tr .lbl { display: inline-block; width: 28px; font-size: .75rem; color: var(--muted); font-weight: 600; }
.forms { display: grid; grid-template-columns: auto 1fr 1fr; gap: 2px 10px; font-size: .9rem; margin-top: 6px; }
.forms span:nth-child(3n+1) { color: var(--muted); font-size: .8rem; }
.hint { color: var(--muted); font-size: .8rem; }
.meaning { font-weight: 600; font-size: 1.05rem; }
.meaning .en { font-weight: 400; color: var(--muted); }
.chg { font-weight: 700; }
.c-m { color: var(--m); }
.c-f { color: var(--f); }
.c-n { color: var(--n); }
.actions { display: flex; gap: 8px; margin-top: auto; }

.btn { border: 1px solid var(--line); background: var(--card); border-radius: 10px; padding: 8px 12px; }
.btn.primary { background: var(--accent); color: #fff; border-color: var(--accent); }
.btn.ok { border-color: var(--ok); color: var(--ok); }
.btn:disabled { opacity: .5; cursor: default; }

.empty { text-align: center; color: var(--muted); padding: 40px 0; }

.list { display: flex; flex-direction: column; gap: 8px; }
.row { background: var(--card); border: 1px solid var(--line); border-radius: 10px; padding: 10px 12px; display: flex; align-items: center; gap: 12px; }
.row .txt { flex: 1; min-width: 0; }
.row .txt small { color: var(--muted); display: block; }

.panel { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 16px; margin-bottom: 14px; }
.panel h2 { margin: 0 0 10px; font-size: 1.05rem; }
.seg { display: inline-flex; border: 1px solid var(--line); border-radius: 10px; overflow: hidden; }
.seg button { border: 0; background: none; padding: 8px 18px; }
.seg button.on { background: var(--accent); color: #fff; }

.exercise .sentence { font-size: 1.35rem; line-height: 2.2; }
.blank {
  display: inline-block; min-width: 48px; text-align: center; border-bottom: 2px solid var(--accent);
  padding: 0 6px; margin: 0 2px; color: var(--accent); font-weight: 600;
}
.blank.cur { background: rgba(110,168,254,.15); }
.blank.right { color: var(--ok); border-color: var(--ok); }
.blank.wrong { color: var(--bad); border-color: var(--bad); }
.opts { display: flex; flex-wrap: wrap; gap: 8px; margin: 14px 0; }
.opts .btn { min-width: 64px; font-size: 1.1rem; }
.feedback { margin: 8px 0; font-weight: 600; }
.feedback.ok { color: var(--ok); }
.feedback.bad { color: var(--bad); }
.score { color: var(--muted); font-size: .9rem; }

/* closed card: only word + example, centered */
.card .face { align-items: center; text-align: center; padding: 12px 0; }
.card .actions { display: none; }
.card.open .actions { display: flex; }

/* exercises */
.toolbar .seg button { padding: 8px 12px; }
.ex-tr { margin: 4px 0 14px; padding: 10px 12px; border-radius: 10px; background: var(--bg); font-size: 1.05rem; }
.blank.wrong { color: var(--ok); border-color: var(--bad); }
.blank .was { color: var(--bad); font-weight: 400; opacity: .8; }
.feedback:empty { display: none; }

/* blanks: neutral, gender colors are reserved for m/f/n */
.blank { color: var(--text); border-bottom-color: var(--text); }
.blank.cur { background: rgba(127,127,127,.18); }
.blank { min-width: 56px; line-height: 1.3; }

/* header row with page-specific controls */
.top-row { max-width: 960px; margin-inline: auto; display: flex; align-items: center; justify-content: space-between; gap: 12px; }
.top-row h1 { margin: 0; }
/* header dropdown (Tailwind UI menu look) */
.dd { position: relative; }
.dd-btn {
  display: inline-flex; align-items: center; gap: 6px;
  background: #fff; color: #111827; border: 0; border-radius: 8px;
  padding: 7px 10px 7px 12px; font-size: .875rem; font-weight: 600;
  box-shadow: 0 1px 2px rgba(0,0,0,.08), inset 0 0 0 1px #d1d5db;
}
.dd-btn:hover { background: #f9fafb; }
.dd-chev { display: inline-flex; width: 18px; height: 18px; color: #9ca3af; }
.dd-chev svg { width: 100%; height: 100%; }
.dd-menu {
  position: absolute; right: 0; top: calc(100% + 8px); z-index: 10; width: 14rem;
  background: #fff; border-radius: 8px; overflow: hidden;
  box-shadow: 0 10px 15px -3px rgba(0,0,0,.15), 0 0 0 1px rgba(0,0,0,.05);
}
.dd-group { padding: 4px 0; }
.dd-group + .dd-group { border-top: 1px solid #f3f4f6; }
.dd-item {
  display: block; width: 100%; text-align: left; background: none; border: 0;
  padding: 8px 16px; font-size: .875rem; color: #374151;
}
.dd-item:hover, .dd-item:focus-visible { background: #f3f4f6; color: #111827; outline: none; }
.dd-item.on { font-weight: 600; color: #111827; background: #eef2ff; }


/* play mode */
.play { max-width: 520px; margin: 8px auto 0; display: flex; flex-direction: column; gap: 14px; }
.play-card { min-height: 220px; }
.play-card .face { flex: 1; justify-content: center; padding: 32px 0; }
.play-card .word { font-size: 2.2rem; }
.play-nav { display: flex; align-items: center; gap: 12px; }
.play-nav .btn { margin-left: auto; padding: 10px 18px; }
.play-nav .count { margin-left: 0; }

/* pronunciation */
.card { position: relative; }
.speak {
  position: absolute; top: 10px; right: 10px; width: 36px; height: 36px; padding: 7px;
  border: 1px solid var(--line); border-radius: 999px; background: var(--card); color: var(--muted);
}
.speak:hover { color: var(--text); }
.speak.playing { color: var(--accent); border-color: var(--accent); }
.speak svg { width: 100%; height: 100%; display: block; }