:root {
  --bg: #f4f6fb;
  --card: #ffffff;
  --text: #1f2937;
  --muted: #6b7280;
  --line: #e5e7eb;
  --primary: #4f46e5;
  --primary-soft: #eef2ff;
  --ok: #16a34a;
  --ok-soft: #dcfce7;
  --bad: #dc2626;
  --bad-soft: #fee2e2;
  --warn: #d97706;
  --warn-soft: #fef3c7;
  --shadow: 0 1px 2px rgba(0,0,0,.05), 0 4px 16px rgba(17,24,39,.06);
  --radius: 14px;
  --img-bg: #ffffff;
}
[data-theme="dark"] {
  --bg: #0f172a;
  --card: #1e293b;
  --text: #e5e7eb;
  --muted: #94a3b8;
  --line: #334155;
  --primary: #818cf8;
  --primary-soft: #312e81;
  --ok: #4ade80;
  --ok-soft: #14532d;
  --bad: #f87171;
  --bad-soft: #7f1d1d;
  --warn: #fbbf24;
  --warn-soft: #78350f;
  --shadow: 0 1px 2px rgba(0,0,0,.3), 0 4px 16px rgba(0,0,0,.25);
}

* { box-sizing: border-box; }
html, body { margin: 0; }
body {
  font-family: "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.55;
  font-size: 16px;
}
a { color: var(--primary); text-decoration: none; }
button { font: inherit; color: inherit; }
img { max-width: 100%; }
.container { max-width: 1320px; margin: 0 auto; padding: 24px 16px 64px; }
.hidden { display: none !important; }
.muted { color: var(--muted); }
.small { font-size: 13px; }

/* ---------- Topbar ---------- */
.topbar {
  position: sticky; top: 0; z-index: 30;
  background: var(--card);
  border-bottom: 1px solid var(--line);
}
.topbar-inner {
  max-width: 1320px; margin: 0 auto; padding: 10px 16px;
  display: flex; align-items: center; gap: 16px;
}
.brand { display: flex; align-items: center; gap: 10px; color: var(--text); font-weight: 700; }
.brand-logo {
  width: 36px; height: 36px; border-radius: 10px;
  display: grid; place-items: center;
  background: linear-gradient(135deg, #6366f1, #a855f7);
  color: #fff; font-weight: 800; letter-spacing: .5px;
}
.brand-text small { display: block; font-weight: 500; font-size: 12px; color: var(--muted); line-height: 1; }
.nav { display: flex; gap: 4px; margin-left: auto; }
.nav a {
  padding: 8px 12px; border-radius: 10px; color: var(--muted); font-weight: 600; font-size: 15px;
}
.nav a:hover { background: var(--primary-soft); color: var(--primary); }
.nav a.active { background: var(--primary); color: #fff; }
.icon-btn {
  border: 1px solid var(--line); background: var(--card);
  width: 38px; height: 38px; border-radius: 10px; cursor: pointer; font-size: 18px;
}
.menu-btn { display: none; }

/* ---------- Generic UI ---------- */
.card {
  background: var(--card); border: 1px solid var(--line);
  border-radius: var(--radius); box-shadow: var(--shadow);
  padding: 20px;
}
.page-title { font-size: 26px; margin: 0 0 4px; }
.page-sub { margin: 0 0 20px; color: var(--muted); }
.row { display: flex; gap: 12px; flex-wrap: wrap; align-items: center; }
.spacer { flex: 1; }
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  padding: 10px 18px; border-radius: 10px; border: 1px solid var(--line);
  background: var(--card); cursor: pointer; font-weight: 600; white-space: nowrap;
}
.btn:hover { border-color: var(--primary); color: var(--primary); }
.btn:disabled { opacity: .5; cursor: not-allowed; }
.btn-primary { background: var(--primary); border-color: var(--primary); color: #fff; }
.btn-primary:hover { filter: brightness(1.08); color: #fff; }
.btn-ok { background: var(--ok); border-color: var(--ok); color: #fff; }
.btn-ok:hover { color: #fff; filter: brightness(1.08); }
.btn-danger { color: var(--bad); }
.btn-danger:hover { border-color: var(--bad); color: var(--bad); }
.btn-lg { padding: 13px 26px; font-size: 17px; }
.btn-sm { padding: 6px 12px; font-size: 14px; }
.badge {
  display: inline-block; padding: 2px 10px; border-radius: 999px;
  font-size: 13px; font-weight: 600; background: var(--primary-soft); color: var(--primary);
}
.badge-ok { background: var(--ok-soft); color: var(--ok); }
.badge-bad { background: var(--bad-soft); color: var(--bad); }
.badge-warn { background: var(--warn-soft); color: var(--warn); }
.badge-gray { background: var(--line); color: var(--muted); }

/* ---------- Dashboard ---------- */
.stats { display: grid; grid-template-columns: repeat(auto-fit, minmax(170px, 1fr)); gap: 14px; margin-bottom: 22px; }
.stat { padding: 16px 18px; }
.stat .label { color: var(--muted); font-size: 14px; font-weight: 600; }
.stat .value { font-size: 30px; font-weight: 800; line-height: 1.2; margin-top: 4px; }
.stat .hint { color: var(--muted); font-size: 13px; }
.progress { height: 8px; background: var(--line); border-radius: 99px; overflow: hidden; margin-top: 10px; }
.progress > span { display: block; height: 100%; background: var(--primary); border-radius: 99px; }
.modes { display: grid; grid-template-columns: repeat(auto-fit, minmax(250px, 1fr)); gap: 16px; margin-bottom: 26px; }
.mode { display: flex; flex-direction: column; gap: 10px; }
.mode .ico { font-size: 30px; }
.mode h3 { margin: 0; font-size: 19px; }
.mode p { margin: 0; color: var(--muted); flex: 1; }
.section-title { font-size: 19px; margin: 6px 0 12px; }

/* ---------- Setup forms ---------- */
.setup { max-width: 760px; }
.field { margin-bottom: 20px; }
.field > label, .field > .label { display: block; font-weight: 700; margin-bottom: 8px; }
.chips { display: flex; gap: 8px; flex-wrap: wrap; }
.chip {
  padding: 8px 14px; border-radius: 999px; border: 1px solid var(--line);
  background: var(--card); cursor: pointer; font-weight: 600; font-size: 15px;
}
.chip:hover { border-color: var(--primary); }
.chip.active { background: var(--primary); border-color: var(--primary); color: #fff; }
.input, select.input {
  padding: 9px 12px; border-radius: 10px; border: 1px solid var(--line);
  background: var(--card); color: var(--text); font: inherit; min-width: 0;
}
.input:focus { outline: 2px solid var(--primary); outline-offset: 0; }
.input-num { width: 100px; }
.check { display: flex; align-items: center; gap: 8px; cursor: pointer; }
.pool-info { margin-top: 6px; color: var(--muted); font-size: 14px; }

/* ---------- Quiz ---------- */
.quiz { display: grid; grid-template-columns: minmax(0, 1fr) 260px; gap: 20px; align-items: start; }
.quiz-head {
  display: flex; align-items: center; gap: 12px; flex-wrap: wrap;
  margin-bottom: 14px;
}
.quiz-head h2 { margin: 0; font-size: 20px; }
.timer {
  font-variant-numeric: tabular-nums; font-weight: 800; font-size: 18px;
  padding: 6px 14px; border-radius: 10px; background: var(--primary-soft); color: var(--primary);
}
.timer.low { background: var(--bad-soft); color: var(--bad); animation: pulse 1s infinite; }
@keyframes pulse { 50% { opacity: .6; } }
.qcard { padding: 22px 24px; }
.qmeta { display: flex; gap: 8px; align-items: center; margin-bottom: 12px; flex-wrap: wrap; }
.qnum { font-weight: 800; font-size: 18px; }
.qtext { font-size: 18px; white-space: pre-line; margin-bottom: 16px; }
.qimg {
  display: block; background: var(--img-bg); border-radius: 10px; padding: 8px;
  border: 1px solid var(--line); margin-bottom: 16px; cursor: zoom-in; max-width: 100%;
}
.qimg img { display: block; max-width: 100%; height: auto; }
.opts { display: grid; gap: 10px; }
.opts.grid-img { grid-template-columns: repeat(auto-fill, minmax(170px, 1fr)); }
.opt {
  display: flex; align-items: center; gap: 14px; text-align: left;
  padding: 12px 14px; border-radius: 12px; border: 2px solid var(--line);
  background: var(--card); cursor: pointer; font-size: 17px; width: 100%;
  transition: border-color .12s, background .12s;
}
.opt:hover:not(:disabled) { border-color: var(--primary); }
.opt:disabled { cursor: default; }
.opt .letter {
  flex: none; width: 34px; height: 34px; border-radius: 50%;
  display: grid; place-items: center; font-weight: 800; font-size: 15px;
  background: var(--line); color: var(--text);
}
.opt .txt { flex: 1; }
.opt-img { flex-direction: column; align-items: center; gap: 8px; padding: 10px; }
.opt-img .letter { align-self: flex-start; }
.opt-img .pic { background: #fff; border-radius: 8px; padding: 4px; display: grid; place-items: center; width: 100%; }
.opt-img img { max-height: 260px; width: auto; }
.opt.selected { border-color: var(--primary); background: var(--primary-soft); }
.opt.selected .letter { background: var(--primary); color: #fff; }
.opt.correct { border-color: var(--ok); background: var(--ok-soft); }
.opt.correct .letter { background: var(--ok); color: #fff; }
.opt.wrong { border-color: var(--bad); background: var(--bad-soft); }
.opt.wrong .letter { background: var(--bad); color: #fff; }
.opt .mark { margin-left: auto; font-weight: 800; }
.opt.correct .mark { color: var(--ok); }
.opt.wrong .mark { color: var(--bad); }
.sheet-img { margin-bottom: 14px; }

.feedback {
  margin-top: 16px; padding: 12px 16px; border-radius: 12px; font-weight: 600;
}
.feedback.ok { background: var(--ok-soft); color: var(--ok); }
.feedback.bad { background: var(--bad-soft); color: var(--bad); }
.quiz-nav { display: flex; gap: 10px; margin-top: 18px; flex-wrap: wrap; }
.flag-on { border-color: var(--warn) !important; color: var(--warn) !important; }
.kbd-hint { margin-top: 14px; font-size: 13px; color: var(--muted); }
kbd {
  border: 1px solid var(--line); border-bottom-width: 2px; border-radius: 5px;
  padding: 0 5px; font-size: 12px; background: var(--bg);
}

.side { position: sticky; top: 76px; }
.side .card { padding: 16px; }
.side-stats { display: grid; grid-template-columns: 1fr 1fr; gap: 8px; margin-bottom: 12px; }
.side-stats div { background: var(--bg); border-radius: 10px; padding: 8px 10px; }
.side-stats b { display: block; font-size: 20px; }
.side-stats span { font-size: 12px; color: var(--muted); }
.palette {
  display: grid; grid-template-columns: repeat(6, 1fr); gap: 6px;
  max-height: 46vh; overflow: auto; padding: 2px;
}
.pal {
  aspect-ratio: 1; border-radius: 8px; border: 1px solid var(--line);
  background: var(--card); cursor: pointer; font-size: 13px; font-weight: 700;
  position: relative;
}
.pal.answered { background: var(--primary-soft); border-color: var(--primary); color: var(--primary); }
.pal.ok { background: var(--ok); border-color: var(--ok); color: #fff; }
.pal.bad { background: var(--bad); border-color: var(--bad); color: #fff; }
.pal.cur { outline: 2px solid var(--text); outline-offset: 1px; }
.pal.flag::after {
  content: ""; position: absolute; top: 2px; right: 2px; width: 7px; height: 7px;
  border-radius: 50%; background: var(--warn);
}
.legend { display: flex; gap: 10px; flex-wrap: wrap; font-size: 12px; color: var(--muted); margin-top: 10px; }
.legend i { display: inline-block; width: 10px; height: 10px; border-radius: 3px; margin-right: 4px; vertical-align: -1px; border: 1px solid var(--line); }
.side-toggle { display: none; }

/* ---------- Result ---------- */
.result-hero { display: grid; grid-template-columns: 220px 1fr; gap: 24px; align-items: center; margin-bottom: 22px; }
.ring {
  width: 200px; height: 200px; border-radius: 50%;
  display: grid; place-items: center; margin: 0 auto;
}
.ring-inner {
  width: 160px; height: 160px; border-radius: 50%; background: var(--card);
  display: grid; place-items: center; text-align: center;
}
.ring-score { font-size: 46px; font-weight: 900; line-height: 1; }
.ring-sub { color: var(--muted); font-weight: 600; font-size: 14px; }
.result-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(130px, 1fr)); gap: 10px; margin: 14px 0; }
.result-grid div { background: var(--bg); border-radius: 12px; padding: 10px 14px; }
.result-grid b { display: block; font-size: 22px; }
.result-grid span { color: var(--muted); font-size: 13px; }
.verdict { font-size: 22px; font-weight: 800; margin: 0 0 4px; }

.review-item { margin-bottom: 14px; }
.review-item .qtext { font-size: 16px; margin-bottom: 12px; }
.review-item .opt { font-size: 15px; padding: 8px 12px; }
.review-item .opt .letter { width: 28px; height: 28px; font-size: 13px; }
.review-item .opt-img img { max-height: 160px; }
.note { margin-top: 10px; font-size: 14px; color: var(--warn); }

/* ---------- Browse / history ---------- */
.toolbar { display: flex; gap: 10px; flex-wrap: wrap; align-items: center; margin-bottom: 16px; }
.toolbar .input { flex: 1; min-width: 200px; }
.toolbar select.input { flex: none; min-width: 170px; }
.pager { display: flex; gap: 6px; justify-content: center; flex-wrap: wrap; margin-top: 18px; }
.pager button { min-width: 40px; }
table.hist { width: 100%; border-collapse: collapse; }
table.hist th, table.hist td { padding: 10px 12px; border-bottom: 1px solid var(--line); text-align: left; }
table.hist th { color: var(--muted); font-size: 13px; text-transform: uppercase; letter-spacing: .4px; }
table.hist tr:hover td { background: var(--bg); }
.table-wrap { overflow-x: auto; }
.empty { text-align: center; padding: 40px 10px; color: var(--muted); }
.empty .big { font-size: 42px; }

/* ---------- Lightbox & toast ---------- */
.lightbox {
  position: fixed; inset: 0; z-index: 100; background: rgba(15, 23, 42, .85);
  display: grid; place-items: center; padding: 20px; overflow: auto; cursor: zoom-out;
}
.lightbox img { background: #fff; border-radius: 10px; padding: 10px; max-width: none; max-height: none; }
.lightbox[hidden] { display: none; }
.toast {
  position: fixed; left: 50%; bottom: 24px; transform: translateX(-50%); z-index: 110;
  background: #111827; color: #fff; padding: 10px 18px; border-radius: 10px; font-weight: 600;
  box-shadow: var(--shadow);
}
.toast[hidden] { display: none; }

/* ---------- Responsive ---------- */
@media (max-width: 960px) {
  .quiz { grid-template-columns: 1fr; }
  .side { position: static; }
  .side-toggle { display: inline-flex; }
  .palette { max-height: none; }
  .side .card.collapsed .palette, .side .card.collapsed .legend { display: none; }
}
@media (max-width: 820px) {
  .menu-btn { display: inline-block; }
  .nav {
    display: none; position: absolute; top: 58px; left: 0; right: 0;
    flex-direction: column; background: var(--card); padding: 10px; border-bottom: 1px solid var(--line);
  }
  .nav.open { display: flex; }
  .brand-text { font-size: 15px; }
  #themeBtn { margin-left: auto; }
  .result-hero { grid-template-columns: 1fr; }
  .qcard { padding: 16px; }
  .qtext { font-size: 17px; }
  .palette { grid-template-columns: repeat(8, 1fr); }
  .opts.grid-img { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .opt-img img { max-height: 160px; }
  .kbd-hint { display: none; }
  .quiz-nav .btn { flex: 1; }
  .quiz-nav .spacer { display: none; }
}