:root {
  --bg: #f6f7f9; --card: #ffffff; --ink: #1d2330; --sub: #6b7385; --line: #e4e7ed;
  --accent: #2f6fed; --accent-ink: #ffffff; --ok: #1f9d63; --ok-bg: #e6f6ee; --ng: #d6453d; --ng-bg: #fdeceb;
  --warn: #e0a030; --hl: #fff0a8; --sel: #cfe0ff; --radius: 14px;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #12151b; --card: #1b1f27; --ink: #e8ebf2; --sub: #9aa3b5; --line: #2a303b;
    --accent: #6f9bff; --accent-ink: #0d1220; --ok: #4cc88a; --ok-bg: #16322a; --ng: #ff7a72; --ng-bg: #3a1f1f;
    --warn: #e8b64f; --hl: #5a4c12; --sel: #27406f;
  }
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0; background: var(--bg); color: var(--ink);
  font: 16px/1.6 system-ui, -apple-system, "Hiragino Sans", "Yu Gothic UI", "Noto Sans JP", sans-serif;
  padding-bottom: calc(76px + env(safe-area-inset-bottom));
}
main { max-width: 640px; margin: 0 auto; padding: 16px; }
h1 { font-size: 22px; margin: 8px 0 14px; }
h3 { font-size: 15px; margin: 14px 0 8px; }
h3:first-child { margin-top: 0; }
a { color: var(--accent); text-decoration: none; }
p { margin: 8px 0; }
ul { margin: 6px 0; padding-left: 20px; }
.small { font-size: 13px; }
.muted, .hint, .sub { color: var(--sub); }
.hint { font-size: 13px; }
.sub { font-size: 14px; }
.pad { padding: 0 4px; }
.center { text-align: center; }
.num { font-variant-numeric: tabular-nums; }
.okc { color: var(--ok); } .ngc { color: var(--ng); }

.card { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 16px; margin: 0 0 12px; }
.card.err { border-color: var(--ng); } .card.warn { border-color: var(--warn); }
.big { font-size: 54px; font-weight: 700; line-height: 1.1; letter-spacing: -1px; }
.big.dim { font-size: 30px; color: var(--sub); }

.row { display: flex; gap: 10px; align-items: flex-end; flex-wrap: wrap; }
.row > label { flex: 1; min-width: 90px; }
.row.sp { justify-content: space-between; align-items: center; }
.row > select { flex: 1; }
label { display: block; font-size: 13px; color: var(--sub); margin: 8px 0; }
input, select {
  display: block; width: 100%; font: inherit; color: var(--ink); background: var(--bg);
  border: 1px solid var(--line); border-radius: 10px; padding: 10px 12px; margin-top: 4px;
}
input:focus, select:focus { outline: 2px solid var(--accent); outline-offset: 0; }
.row input[type=date] { flex: 1; }

.btn {
  display: inline-block; font: inherit; font-weight: 600; text-align: center; cursor: pointer;
  background: var(--card); color: var(--ink); border: 1px solid var(--line); border-radius: 12px;
  padding: 11px 16px; min-height: 44px; margin: 6px 0;
}
.btn.primary { background: var(--accent); color: var(--accent-ink); border-color: var(--accent); }
.btn.danger { color: var(--ng); border-color: var(--ng); }
.btn.sm { padding: 6px 12px; min-height: 36px; font-size: 14px; margin: 2px 0; }
.btn.wide { display: block; width: 100%; margin: 10px 0; }
.btn:disabled { opacity: .45; cursor: default; }
.link { background: none; border: 0; color: var(--sub); font: inherit; cursor: pointer; padding: 6px; }

.chips { display: flex; gap: 8px; flex-wrap: wrap; }
.chip { font: inherit; background: var(--bg); color: var(--ink); border: 1px solid var(--line); border-radius: 999px; padding: 8px 14px; min-height: 40px; cursor: pointer; }
.chip.on { background: var(--accent); color: var(--accent-ink); border-color: var(--accent); }

#tabs {
  position: fixed; left: 0; right: 0; bottom: 0; display: flex; background: var(--card); border-top: 1px solid var(--line);
  padding-bottom: env(safe-area-inset-bottom); z-index: 5;
}
#tabs a { flex: 1; text-align: center; padding: 8px 0 6px; font-size: 11px; color: var(--sub); }
#tabs a i { display: block; font-style: normal; font-size: 20px; line-height: 1.2; }
#tabs a.on { color: var(--accent); font-weight: 700; }
body[data-route=quiz] #tabs, body[data-route=explain] #tabs { display: none; }
body[data-route=quiz], body[data-route=explain] { padding-bottom: 24px; }

.topbar { display: flex; align-items: center; gap: 10px; margin-bottom: 10px; }
.qhead { display: flex; align-items: center; gap: 10px; margin-bottom: 10px; font-size: 14px; color: var(--sub); }
.bar { flex: 1; height: 6px; background: var(--line); border-radius: 3px; overflow: hidden; }
.bar i { display: block; height: 100%; background: var(--accent); }
.qno { font-size: 13px; color: var(--sub); }
.stem { font-size: 18px; margin: 8px 0 14px; }
.word { font-size: 34px; font-weight: 700; margin: 8px 0 4px; word-break: break-word; }

.choices { display: grid; gap: 10px; }
.choice {
  display: flex; gap: 12px; align-items: flex-start; text-align: left; font: inherit; color: var(--ink);
  background: var(--bg); border: 1px solid var(--line); border-radius: 12px; padding: 12px 14px; min-height: 52px; cursor: pointer;
}
.choice b { width: 24px; flex: none; color: var(--sub); }
.choice.ok { background: var(--ok-bg); border-color: var(--ok); }
.choice.ng { background: var(--ng-bg); border-color: var(--ng); }
.choice:disabled { cursor: default; color: var(--ink); }
.fb { margin: 14px 0 4px; padding: 12px 14px; border-radius: 12px; }
.fb.ok { background: var(--ok-bg); } .fb.ng { background: var(--ng-bg); }
.exp { margin: 8px 0 0; font-size: 14px; }

.passwrap { max-height: 40vh; overflow-y: auto; margin-bottom: 12px; border: 1px solid var(--line); border-radius: var(--radius); background: var(--card); padding: 4px 14px; position: sticky; top: 0; z-index: 2; }
.passfull { border: 1px solid var(--line); border-radius: var(--radius); padding: 4px 14px; background: var(--bg); }
.navrow { display: flex; gap: 10px; margin-top: 12px; }
.navrow .btn { flex: 1; margin: 0; }
.choice.picked { background: var(--sel); border-color: var(--accent); }
.big.sm { font-size: 36px; }
.stem.sm { font-size: 16px; margin: 6px 0 4px; }
.ja { font-size: 13px; color: var(--sub); margin: 2px 0 6px; }
.clist { display: grid; gap: 6px; margin: 8px 0; }
.crow { display: flex; gap: 10px; align-items: flex-start; padding: 8px 10px; border: 1px solid var(--line); border-radius: 10px; font-size: 14px; }
.crow b { width: 20px; flex: none; color: var(--sub); }
.crow.ok { background: var(--ok-bg); border-color: var(--ok); }
.crow.ng { background: var(--ng-bg); border-color: var(--ng); }
details.trans summary { cursor: pointer; font-weight: 700; font-size: 15px; }
details.trans .ptext { margin-top: 8px; font-size: 15px; }
.qexp .exp { white-space: pre-wrap; }
.passage { padding: 8px 0; }
.passage + .passage { border-top: 1px dashed var(--line); }
.ptitle { font-size: 12px; color: var(--sub); }
.ptext { white-space: pre-wrap; font-size: 16px; line-height: 1.75; word-break: break-word; }
.tok { border-radius: 4px; cursor: pointer; }
.tok.sel { background: var(--sel); box-shadow: 0 0 0 2px var(--sel); }
.tok.hl, .hl { background: var(--hl); border-radius: 4px; }
/* 青枠の語彙は、見た目は通常の語と同じ(タップしたときだけ吹き出しで意味を表示する) */
#vbubble {
  position: absolute; z-index: 12; max-width: 240px; padding: 8px 12px; border-radius: 10px;
  background: var(--ink); color: var(--bg); box-shadow: 0 4px 16px rgba(0,0,0,.28); font-size: 14px; line-height: 1.4;
}
#vbubble .vt { font-size: 12px; opacity: .7; }
#vbubble .vm { font-weight: 700; font-size: 15px; margin-top: 1px; }
#vbubble .vadd { margin-top: 6px; font: inherit; font-size: 12px; color: var(--bg); background: transparent; border: 1px solid currentColor; border-radius: 999px; padding: 2px 10px; opacity: .85; cursor: pointer; }
#vbubble::after { content: ''; position: absolute; left: var(--ax, 20px); margin-left: -6px; border: 6px solid transparent; }
#vbubble.up::after { top: 100%; border-top-color: var(--ink); }
#vbubble.down::after { bottom: 100%; border-bottom-color: var(--ink); }
.blank { color: var(--sub); font-weight: 700; }
.blank.cur { color: var(--accent-ink); background: var(--accent); border-radius: 4px; padding: 0 3px; }

.selbar {
  position: fixed; left: 12px; right: 12px; bottom: calc(80px + env(safe-area-inset-bottom)); z-index: 9;
  display: none; align-items: center; gap: 8px; background: var(--ink); color: var(--bg);
  border-radius: 14px; padding: 10px 12px; box-shadow: 0 6px 24px rgba(0,0,0,.25);
}
.selbar.show { display: flex; }
.selbar .sl { flex: 1; font-weight: 700; word-break: break-word; }
body[data-route=quiz] .selbar { bottom: 16px; }
.selbar .btn { margin: 0; }

.list .item, .list .item2 { display: flex; justify-content: space-between; align-items: center; gap: 10px; padding: 10px 0; border-bottom: 1px solid var(--line); color: var(--ink); }
.list .item:last-child { border-bottom: 0; }
.item2 { padding: 8px 0; border-bottom: 1px solid var(--line); }
.tag { font-size: 11px; background: var(--bg); border: 1px solid var(--line); color: var(--sub); border-radius: 6px; padding: 0 6px; }
.src { font-size: 12px; color: var(--accent); white-space: nowrap; }
.occ { padding: 10px 0; border-bottom: 1px solid var(--line); }
.occ:last-child { border-bottom: 0; }
.snip { font-size: 14px; margin: 4px 0 6px; }
mark { background: var(--hl); color: inherit; border-radius: 3px; padding: 0 2px; }
.wr { padding: 8px 0; border-bottom: 1px solid var(--line); }
.wr:last-child { border-bottom: 0; }

.hbar { display: grid; grid-template-columns: 78px 1fr 44px 44px; gap: 8px; align-items: center; margin: 8px 0; font-size: 14px; }
.hbar b { text-align: right; }
.track { height: 10px; background: var(--line); border-radius: 5px; overflow: hidden; }
.track i { display: block; height: 100%; background: var(--accent); }
.track i.warn { background: var(--warn); }
.vbars { display: flex; gap: 3px; align-items: flex-end; height: 120px; margin-top: 8px; }
.vb { flex: 1; min-width: 0; display: flex; flex-direction: column; align-items: center; height: 100%; }
.vb .col { flex: 1; width: 100%; display: flex; align-items: flex-end; }
.vb .n { display: block; width: 100%; background: var(--line); border-radius: 3px 3px 0 0; position: relative; min-height: 2px; }
.vb .n .ok { position: absolute; left: 0; right: 0; bottom: 0; background: var(--accent); border-radius: 3px 3px 0 0; }
.vb span { font-size: 9px; color: var(--sub); margin-top: 3px; white-space: nowrap; overflow: hidden; }

#overlay { display: none; position: fixed; inset: 0; background: rgba(0,0,0,.45); z-index: 20; align-items: center; justify-content: center; padding: 16px; }
#overlay.show { display: flex; }
.modal { background: var(--card); border-radius: 16px; padding: 18px; width: 100%; max-width: 420px; max-height: 85vh; overflow: auto; }
.modal h3 { font-size: 17px; }
.mbtns { display: flex; gap: 8px; justify-content: flex-end; flex-wrap: wrap; margin-top: 10px; }
#sheet { display: none; position: fixed; inset: 0; z-index: 15; }
#sheet.show { display: block; }
#sheet .backdrop { position: absolute; inset: 0; background: rgba(0,0,0,.4); }
#sheet .panel { position: absolute; left: 0; right: 0; bottom: 0; max-width: 640px; margin: 0 auto; background: var(--card); border-radius: 18px 18px 0 0; padding: 16px 16px calc(16px + env(safe-area-inset-bottom)); max-height: 90vh; overflow: auto; }
#toast { position: fixed; left: 50%; bottom: 96px; transform: translateX(-50%); background: var(--ink); color: var(--bg); padding: 10px 16px; border-radius: 999px; font-size: 14px; z-index: 30; opacity: 0; pointer-events: none; transition: opacity .2s; max-width: 90vw; text-align: center; }
#toast.show { opacity: 1; }