:root {
  --bg: #0f1419;
  --panel: #1a2129;
  --panel2: #222c37;
  --border: #2e3a47;
  --text: #e6edf3;
  --muted: #9aa7b4;
  --accent: #4493f8;
  --green: #2ea043;
  --orange: #d98023;
  --red: #e5534b;
  --gray: #6b7785;
}
* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
html { -webkit-text-size-adjust: 100%; text-size-adjust: 100%; }
body {
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Apple SD Gothic Neo",
    "Malgun Gothic", sans-serif;
  line-height: 1.6;
  overflow-x: hidden;
  -webkit-tap-highlight-color: transparent;
}
#topbar {
  display: flex; align-items: center; justify-content: space-between;
  gap: 12px; padding: 12px 20px; border-bottom: 1px solid var(--border);
  background: var(--panel); position: sticky; top: 0; z-index: 10;
  /* iPhone notch / Dynamic Island safe area */
  padding-top: calc(12px + env(safe-area-inset-top));
  padding-left: calc(20px + env(safe-area-inset-left));
  padding-right: calc(20px + env(safe-area-inset-right));
}
#topbar .title { font-weight: 700; font-size: 15px; }
#topbar .title small { color: var(--muted); font-weight: 400; }
#topbar .right { display: flex; gap: 8px; align-items: center; }
main { max-width: 920px; margin: 0 auto; padding: 20px; }

button {
  font: inherit; cursor: pointer; border-radius: 8px; border: 1px solid var(--border);
  background: var(--panel2); color: var(--text); padding: 8px 14px;
}
button:hover { border-color: var(--accent); }
button.primary { background: var(--accent); border-color: var(--accent); color: #fff; font-weight: 600; }
button.ghost { background: transparent; }
button.small { padding: 4px 10px; font-size: 13px; }
button:disabled { opacity: 0.45; cursor: not-allowed; }
button.active { background: var(--accent); border-color: var(--accent); color: #fff; }

.banner {
  background: #2a2010; border: 1px solid #5a4413; color: #f0d896;
  padding: 10px 14px; border-radius: 8px; font-size: 13px; margin-bottom: 16px;
}
.card { background: var(--panel); border: 1px solid var(--border); border-radius: 12px; padding: 18px; margin-bottom: 16px; }
.grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 12px; }
.mode-card { background: var(--panel2); border: 1px solid var(--border); border-radius: 10px; padding: 16px; }
.mode-card h3 { margin: 0 0 6px; }
.mode-card p { margin: 0 0 12px; color: var(--muted); font-size: 13px; }

.stat-row { display: flex; gap: 18px; flex-wrap: wrap; }
.stat { background: var(--panel2); border-radius: 8px; padding: 10px 14px; min-width: 110px; }
.stat .n { font-size: 22px; font-weight: 700; }
.stat .l { font-size: 12px; color: var(--muted); }

.cov-bar { height: 12px; border-radius: 6px; overflow: hidden; display: flex; background: var(--panel2); }
.cov-bar > span { display: block; height: 100%; }
.cov-confirmed { background: var(--green); }
.cov-corrected { background: var(--orange); }
.cov-uncertain { background: var(--gray); }
.cov-unverified { background: #3a4654; }
.cov-legend { display: flex; gap: 14px; flex-wrap: wrap; font-size: 12px; color: var(--muted); margin-top: 8px; }
.cov-legend i { display: inline-block; width: 10px; height: 10px; border-radius: 2px; margin-right: 4px; vertical-align: middle; }

label.field { display: block; margin: 10px 0; }
label.field span { display: inline-block; min-width: 160px; color: var(--muted); }
input[type="number"] { width: 90px; background: var(--panel2); color: var(--text); border: 1px solid var(--border); border-radius: 6px; padding: 6px 8px; font: inherit; }

/* Quiz */
.qprogress { display: flex; align-items: center; gap: 12px; margin-bottom: 12px; color: var(--muted); font-size: 13px; }
.qprogress .bar { flex: 1; height: 6px; background: var(--panel2); border-radius: 3px; overflow: hidden; }
.qprogress .bar > span { display: block; height: 100%; background: var(--accent); }
.stem { font-size: 16px; margin: 8px 0 16px; white-space: pre-wrap; }
.opt { display: flex; gap: 10px; align-items: flex-start; padding: 12px 14px; border: 1px solid var(--border); border-radius: 10px; margin-bottom: 10px; cursor: pointer; background: var(--panel); }
.opt:hover { border-color: var(--accent); }
.opt.sel { border-color: var(--accent); background: #16263c; }
.opt.correct { border-color: var(--green); background: #102a18; }
.opt.wrong { border-color: var(--red); background: #2a1414; }
.opt input { margin-top: 4px; }
.opt .k { font-weight: 700; margin-right: 4px; }
.hint { color: var(--muted); font-size: 13px; margin-bottom: 8px; }
.nav { display: flex; justify-content: space-between; gap: 10px; margin-top: 16px; }
.nav .mid { display: flex; gap: 8px; align-items: center; }

/* Badges */
.badge { display: inline-block; font-size: 12px; font-weight: 600; padding: 2px 8px; border-radius: 999px; }
.badge.confirmed { background: #102a18; color: var(--green); border: 1px solid var(--green); }
.badge.corrected { background: #2a1f10; color: var(--orange); border: 1px solid var(--orange); }
.badge.uncertain { background: #20262e; color: var(--muted); border: 1px solid var(--gray); }
.badge.unverified { background: transparent; color: var(--muted); border: 1px dashed var(--gray); }
.badge.pass { background: var(--green); color: #fff; }
.badge.fail { background: var(--red); color: #fff; }

/* Explanation panel */
.expl { background: var(--panel2); border: 1px solid var(--border); border-radius: 10px; padding: 14px; margin-top: 14px; }
.expl h4 { margin: 0 0 8px; }
.expl .ko { white-space: pre-wrap; }
.expl .answer-line { margin: 6px 0 10px; }
.docs { margin: 10px 0 0; padding-left: 18px; }
.docs li { margin: 4px 0; }
.docs a { color: var(--accent); }
details.orig { margin-top: 10px; }
details.orig summary { cursor: pointer; color: var(--muted); }
details.orig .raw { white-space: pre-wrap; color: var(--muted); font-size: 13px; margin-top: 8px; }

/* Result */
.score-big { font-size: 48px; font-weight: 800; }
.dom-table { width: 100%; border-collapse: collapse; margin-top: 8px; }
.dom-table th, .dom-table td { text-align: left; padding: 6px 10px; border-bottom: 1px solid var(--border); }
.qlist { display: grid; grid-template-columns: repeat(auto-fill, minmax(54px, 1fr)); gap: 6px; margin-top: 10px; }
.qlist button { padding: 8px 0; font-size: 13px; }
.qlist button.ok { border-color: var(--green); color: var(--green); }
.qlist button.no { border-color: var(--red); color: var(--red); }
.muted { color: var(--muted); }
.tag { font-size: 12px; color: var(--muted); border: 1px solid var(--border); border-radius: 6px; padding: 1px 6px; margin-left: 6px; }

main {
  padding-bottom: calc(24px + env(safe-area-inset-bottom));
  padding-left: calc(20px + env(safe-area-inset-left));
  padding-right: calc(20px + env(safe-area-inset-right));
}
/* inputs at >=16px so iOS Safari doesn't auto-zoom on focus */
input[type="number"] { font-size: 16px; }

/* ---- Mobile / iPhone ---- */
@media (max-width: 640px) {
  main { padding-top: 14px; }
  .grid { grid-template-columns: 1fr; }
  .card { padding: 14px; border-radius: 10px; }
  #topbar .title small { display: none; } /* keep header compact */
  .stem { font-size: 17px; }
  .opt { padding: 14px; } /* larger tap targets */
  .opt input { transform: scale(1.2); }
  button { padding: 11px 16px; } /* >=44px tap height */
  button.small { padding: 8px 12px; }
  .nav { position: sticky; bottom: 0; background: var(--bg);
    padding: 10px 0 calc(10px + env(safe-area-inset-bottom));
    border-top: 1px solid var(--border); margin-top: 12px; }
  .stat { min-width: 0; flex: 1 1 40%; }
  .score-big { font-size: 40px; }
  .qlist { grid-template-columns: repeat(auto-fill, minmax(44px, 1fr)); }
  .dom-table th, .dom-table td { padding: 6px 6px; font-size: 14px; }
}