:root{
  --app-dvh:100dvh;
  --topbar-height:0px;
  --safe-top:env(safe-area-inset-top, 0px);
  --safe-bottom:env(safe-area-inset-bottom, 0px);
  --page-max:1432px;
  --rail-width:336px;
  --board-size:clamp(340px, 58vw, 748px);
  --bg-1:#eef5ff;
  --bg-2:#dbe9fb;
  --bg-3:#f7fbff;
  --surface:#ffffff;
  --surface-soft:rgba(255,255,255,.95);
  --surface-rail:rgba(245,249,255,.96);
  --line:rgba(17,46,88,.09);
  --line-strong:rgba(17,46,88,.16);
  --text:#162743;
  --text-soft:#60728e;
  --text-faint:#8494ad;
  --accent:#1f66cc;
  --accent-deep:#163f83;
  --accent-soft:#eaf2ff;
  --shadow-panel:0 24px 48px rgba(27,68,132,.12);
  --shadow-card:0 12px 24px rgba(27,68,132,.07);
  --shadow-soft:0 8px 18px rgba(27,68,132,.05);
  --font-ui:"BIZ UDPGothic","Yu Gothic UI","Yu Gothic","Hiragino Sans","Meiryo",sans-serif;
  --font-display:"BIZ UDPGothic","Yu Gothic UI","Yu Gothic","Hiragino Sans","Meiryo",sans-serif;
}

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

html,
body{
  margin:0;
  min-height:100%;
  height:auto;
  overflow:auto;
}

body{
  color:var(--text);
  font-family:var(--font-ui);
  background:
    radial-gradient(circle at 14% 8%, rgba(255,255,255,.85) 0%, rgba(255,255,255,0) 24%),
    radial-gradient(circle at 86% 10%, rgba(193,220,255,.52) 0%, rgba(193,220,255,0) 22%),
    linear-gradient(180deg, var(--bg-1) 0%, var(--bg-2) 46%, var(--bg-3) 100%);
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
}

body::before,
body::after{
  content:"";
  position:fixed;
  pointer-events:none;
  z-index:0;
  border-radius:999px;
}

body::before{
  left:-10vw;
  top:-18vh;
  width:34vw;
  height:40vh;
  background:radial-gradient(circle, rgba(255,255,255,.54) 0%, rgba(255,255,255,0) 72%);
  filter:blur(18px);
}

body::after{
  right:-12vw;
  bottom:-20vh;
  width:40vw;
  height:46vh;
  background:radial-gradient(circle, rgba(152,195,255,.28) 0%, rgba(152,195,255,0) 72%);
  filter:blur(20px);
}

.app,
.topbar,
.stage,
.modal{
  position:relative;
  z-index:1;
}

.app{
  min-height:var(--app-dvh);
  display:grid;
  grid-template-rows:auto auto;
}

.topbar{
  padding:calc(10px + var(--safe-top)) 18px 6px;
}

.brand{
  width:100%;
  max-width:var(--page-max);
  margin:0 auto;
}

.brandBand{
  position:relative;
  display:grid;
  grid-template-columns:minmax(0,1fr) 244px;
  gap:12px;
  align-items:center;
  padding:10px 12px;
  border-radius:26px;
  overflow:hidden;
  border:1px solid rgba(28,84,168,.07);
  background:
    linear-gradient(112deg, rgba(248,252,255,.98) 0%, rgba(229,239,255,.95) 34%, rgba(239,246,255,.95) 66%, rgba(226,238,255,.95) 100%);
  box-shadow:0 14px 28px rgba(28,84,168,.08);
}

.brandBand::before{
  content:"";
  position:absolute;
  inset:0;
  background:
    radial-gradient(circle at 12% 18%, rgba(255,255,255,.86) 0%, rgba(255,255,255,0) 26%),
    radial-gradient(circle at 84% 20%, rgba(255,255,255,.42) 0%, rgba(255,255,255,0) 22%),
    linear-gradient(180deg, rgba(255,255,255,.22), rgba(255,255,255,0) 48%);
  pointer-events:none;
}

.logoWrap{
  position:relative;
  min-width:0;
  min-height:88px;
  display:flex;
  align-items:center;
  justify-content:center;
  padding:8px 18px;
  border-radius:20px;
  overflow:hidden;
  border:1px solid rgba(28,84,168,.06);
  background:
    linear-gradient(180deg, rgba(255,255,255,.99), rgba(241,248,255,.90)),
    linear-gradient(112deg, rgba(214,232,255,.88), rgba(248,251,255,.98));
  box-shadow:
    inset 0 1px 0 rgba(255,255,255,.94),
    inset 0 -10px 16px rgba(206,225,248,.12),
    0 10px 20px rgba(28,84,168,.06);
}

.logoWrap::before{
  content:"";
  position:absolute;
  inset:0;
  background:
    linear-gradient(114deg, rgba(255,255,255,.30), rgba(255,255,255,0) 40%),
    radial-gradient(circle at 88% 16%, rgba(255,255,255,.42) 0%, rgba(255,255,255,0) 26%);
  pointer-events:none;
}

.brandLogoImg{
  position:relative;
  z-index:1;
  display:block;
  width:100%;
  height:100%;
  max-width:none;
  object-fit:contain;
  object-position:center center;
  filter:drop-shadow(0 8px 16px rgba(18,55,110,.10));
}

.brandCopy{
  position:relative;
  z-index:1;
  display:grid;
  gap:6px;
  align-content:center;
  min-width:0;
  padding:12px 14px;
  border-radius:20px;
  border:1px solid rgba(28,84,168,.05);
  background:linear-gradient(180deg, rgba(255,255,255,.42), rgba(245,249,255,.18));
  opacity:.92;
}

.brandEyebrow{
  color:#5d77a0;
  font-size:10px;
  font-weight:800;
  letter-spacing:.2em;
  text-transform:uppercase;
}

.brandTitle{
  margin:0;
  color:var(--accent-deep);
  font-family:var(--font-display);
  font-size:24px;
  font-weight:900;
  line-height:1.15;
}

.brandLead{
  color:var(--text-soft);
  font-size:12px;
  font-weight:700;
  line-height:1.5;
}

.brandDecor{
  display:none;
}

.stage{
  padding:0 18px calc(14px + var(--safe-bottom));
}

.layout{
  width:100%;
  max-width:var(--page-max);
  margin:0 auto;
}

.panel{
  display:grid;
  grid-template-columns:minmax(0,1fr) var(--rail-width);
  align-items:stretch;
  gap:14px;
}

.boardArea{
  min-width:0;
  min-height:0;
  padding:20px 22px 18px;
  border-radius:36px;
  border:1px solid var(--line);
  background:linear-gradient(180deg, rgba(255,255,255,.97), rgba(245,249,255,.90));
  box-shadow:var(--shadow-panel);
  backdrop-filter:blur(14px);
}

.boardStage{
  height:100%;
  display:grid;
  grid-template-rows:auto minmax(0,1fr) auto;
  gap:14px;
}

.boardStageTop{
  display:grid;
  gap:12px;
  justify-items:center;
}

.problemEyebrow{
  display:inline-flex;
  align-items:center;
  justify-content:center;
  width:fit-content;
  min-height:36px;
  padding:0 14px;
  border-radius:999px;
  background:var(--accent-soft);
  border:1px solid rgba(28,84,168,.10);
  color:var(--accent-deep);
  font-size:11px;
  font-weight:900;
  letter-spacing:.12em;
}

.boardStageHeadings{
  display:grid;
  gap:8px;
  width:min(calc(var(--board-max, var(--board-size)) + 44px), 100%);
  max-width:760px;
}

.boardProblemTitle{
  margin:0;
  color:var(--text);
  font-family:var(--font-display);
  font-size:clamp(34px, 3.9vw, 46px);
  font-weight:900;
  line-height:1.08;
  letter-spacing:.01em;
}

.boardProblemMeta{
  margin:0;
  color:var(--text-soft);
  font-size:12px;
  font-weight:700;
  line-height:1.55;
}

.inlineHint{
  display:grid;
  gap:5px;
  padding:13px 16px;
  border-radius:20px;
  border:1px solid rgba(28,84,168,.07);
  border-left:3px solid rgba(31,102,204,.58);
  background:linear-gradient(180deg, rgba(245,250,255,.94), rgba(236,244,255,.84));
  box-shadow:inset 0 1px 0 rgba(255,255,255,.76);
}

.inlineHint.inlineHintSide{
  position:relative;
}

.inlineHintLabel{
  color:var(--accent);
  font-size:11px;
  font-weight:900;
  letter-spacing:.12em;
}

.inlineHintText{
  color:#29426c;
  font-size:16px;
  font-weight:800;
  line-height:1.55;
}

.reviewControls{
  position:absolute;
  left:12px;
  right:12px;
  top:50%;
  transform:translateY(-50%);
  display:block;
  margin:0;
}

.reviewControls[hidden]{
  display:none !important;
}

.reviewControlsRow{
  display:grid;
  grid-template-columns:repeat(3,minmax(0,1fr));
  gap:6px;
}

.inlineHint.inlineHintSide.is-review-mode .inlineHintLabel,
.inlineHint.inlineHintSide.is-review-mode .inlineHintText{
  visibility:hidden;
}

.reviewBtn{
  width:100%;
  min-height:32px;
  padding:0 6px;
  border-radius:999px;
  border:1px solid rgba(29,83,166,.16);
  background:rgba(255,255,255,.92);
  color:#23456f;
  font-size:11px;
  font-weight:900;
  line-height:1;
  box-shadow:0 4px 10px rgba(31,69,128,.05);
}

.reviewBtn:hover:not(:disabled){
  border-color:rgba(29,83,166,.28);
  background:#fff;
}

.reviewBtn:disabled{
  opacity:.5;
  cursor:default;
  box-shadow:none;
}

.reviewBtnAccent{
  border-color:rgba(26,118,82,.18);
  background:linear-gradient(180deg, rgba(240,255,248,.98), rgba(225,248,236,.92));
  color:#1e7a56;
}

.problemTurnText.is-review-hidden{
  visibility:hidden;
  opacity:0;
  pointer-events:none;
}

.boardFrame{
  min-height:0;
  display:flex;
  align-items:center;
  justify-content:center;
  padding-top:2px;
}

.boardShell{
  position:relative;
  width:min(100%, var(--board-max, var(--board-size)));
  height:min(100%, var(--board-max, var(--board-size)));
  max-width:100%;
  max-height:100%;
  aspect-ratio:1 / 1;
  overflow:hidden;
  isolation:isolate;
  outline:none;
  border-radius:34px;
  border:1px solid rgba(121,103,72,.32);
  background:#dfc48d;
  touch-action:manipulation;
  box-shadow:
    0 0 0 10px rgba(245,249,255,.98),
    0 0 0 13px rgba(198,214,237,.42),
    0 18px 34px rgba(36,74,128,.12),
    inset 0 1px 0 rgba(255,255,255,.22);
}

.boardShell.is-keyboard-focus{
  box-shadow:
    0 0 0 10px rgba(245,249,255,.98),
    0 0 0 13px rgba(198,214,237,.42),
    0 0 0 17px rgba(31,102,204,.14),
    0 18px 34px rgba(36,74,128,.12),
    inset 0 1px 0 rgba(255,255,255,.22);
}

.boardShell::before{
  content:"";
  position:absolute;
  inset:0;
  background:linear-gradient(135deg, rgba(255,255,255,.10), rgba(255,255,255,0) 36%);
  pointer-events:none;
  z-index:0;
}

canvas{
  display:block;
  width:100%;
  height:100%;
}

.boardCursor{
  position:absolute;
  left:0;
  top:0;
  width:32px;
  height:32px;
  border-radius:999px;
  border:3px solid rgba(22,63,131,.92);
  background:radial-gradient(circle, rgba(255,255,255,.28), rgba(255,255,255,0) 68%);
  box-shadow:0 0 0 3px rgba(255,255,255,.84), 0 8px 18px rgba(27,68,132,.16);
  transform:translate(-50%,-50%);
  opacity:0;
  pointer-events:none;
  z-index:4;
  transition:opacity .14s ease, left .08s linear, top .08s linear, border-color .12s ease, box-shadow .12s ease, background-color .12s ease;
}

.boardCursor::after{
  content:"";
  position:absolute;
  inset:6px;
  border-radius:999px;
  border:1px solid rgba(255,255,255,.72);
}

.boardCursor.is-visible{
  opacity:1;
}

.boardCursor.is-choice{
  border-color:rgba(31,102,204,.98);
  box-shadow:0 0 0 3px rgba(255,255,255,.88), 0 0 0 8px rgba(31,102,204,.17), 0 8px 18px rgba(27,68,132,.16);
}

.boardCursor.is-occupied{
  border-color:rgba(142,101,37,.92);
  background:radial-gradient(circle, rgba(244,234,214,.34), rgba(244,234,214,0) 68%);
  box-shadow:0 0 0 3px rgba(255,255,255,.84), 0 0 0 8px rgba(202,156,80,.18), 0 8px 18px rgba(84,59,16,.14);
}

.overlayMark{
  position:absolute;
  left:50%;
  top:50%;
  width:min(74%, 392px);
  max-height:58%;
  aspect-ratio:492 / 296;
  transform:translate(-50%,-50%) scale(.84);
  opacity:0;
  pointer-events:none;
  z-index:5;
  transition:opacity .16s ease, transform .24s cubic-bezier(.22,1,.36,1);
  filter:drop-shadow(0 14px 24px rgba(20,26,39,.24));
}

.overlayMark.show{
  opacity:1;
  transform:translate(-50%,-50%) scale(1);
}

.overlayMarkImg{
  display:block;
  width:100%;
  height:100%;
  object-fit:contain;
}

.successExplainCta{
  position:absolute;
  left:50%;
  bottom:6%;
  width:min(60%, 280px);
  min-height:54px;
  padding:14px 18px 12px;
  transform:translate(-50%, 14px);
  opacity:0;
  pointer-events:none;
  z-index:6;
  transition:opacity .18s ease, transform .22s cubic-bezier(.22,1,.36,1);
  box-shadow:0 16px 28px rgba(27,68,132,.16);
}

.successExplainCta[hidden]{
  display:none;
}

.successExplainCta.show{
  opacity:1;
  transform:translate(-50%, 0);
  pointer-events:auto;
}

.successExplainCta:hover:not(:disabled){
  transform:translate(-50%, -2px);
}

.successExplainCta:active:not(:disabled){
  transform:translate(-50%, 0);
}

.successExplainCta .btnMain{
  white-space:nowrap;
}

.boardShell.success::after{
  content:"";
  position:absolute;
  inset:12%;
  border-radius:999px;
  border:8px solid rgba(31,94,168,.18);
  animation:successRipple .76s ease forwards;
  pointer-events:none;
}

@keyframes successRipple{
  0%{transform:scale(.62);opacity:0}
  28%{opacity:1}
  100%{transform:scale(1.18);opacity:0}
}

.boardShell.shake{
  animation:boardShake .38s ease;
}

@keyframes boardShake{
  0%,100%{transform:translateX(0)}
  20%{transform:translateX(-5px)}
  40%{transform:translateX(5px)}
  60%{transform:translateX(-4px)}
  80%{transform:translateX(4px)}
}

.boardStageBottom{
  display:grid;
  gap:12px;
  width:min(calc(var(--board-max, var(--board-size)) + 28px), 100%);
  margin:0 auto;
  padding-top:2px;
}

.btnRow{
  width:100%;
  display:grid;
  gap:12px;
}

.boardActionRow,
.navActionRow{
  grid-template-columns:repeat(2, minmax(0, 1fr));
}

.boardActionRow{
  grid-template-columns:minmax(0,1.05fr) minmax(0,.95fr);
}

button{
  appearance:none;
  min-height:60px;
  margin:0;
  padding:15px 18px 13px;
  display:flex;
  flex-direction:column;
  align-items:center;
  justify-content:center;
  gap:4px;
  border-radius:20px;
  border:1px solid transparent;
  background:#fff;
  color:var(--text);
  font-family:var(--font-ui);
  font-size:15px;
  font-weight:800;
  line-height:1.15;
  letter-spacing:.01em;
  text-align:center;
  cursor:pointer;
  user-select:none;
  transition:transform .14s ease, box-shadow .18s ease, border-color .18s ease, background-color .18s ease, color .18s ease;
}

button:hover:not(:disabled){
  transform:translateY(-2px);
}

button:active:not(:disabled){
  transform:translateY(0);
}

button:focus-visible{
  outline:none;
  box-shadow:0 0 0 4px rgba(31,102,204,.16), 0 12px 22px rgba(27,68,132,.10);
}

button:disabled{
  opacity:.46;
  cursor:default;
  transform:none;
  box-shadow:none;
}

button.primary{
  color:#fff;
  background:linear-gradient(180deg, #2a72d8, #1a56b2);
  border-color:#184b9d;
  box-shadow:0 14px 24px rgba(28,84,168,.18);
}

button.secondary{
  color:var(--accent-deep);
  background:linear-gradient(180deg, rgba(255,255,255,.98), rgba(244,248,255,.94));
  border-color:rgba(28,84,168,.14);
  box-shadow:0 10px 18px rgba(27,68,132,.06);
}

.btnMain{
  display:block;
}

.btnSub{
  display:block;
  font-size:11px;
  font-weight:700;
  line-height:1.3;
  color:inherit;
  opacity:.76;
}

button.primary .btnSub{
  color:rgba(241,247,255,.82);
}

.actionBtn .btnMain,
.navActionRow .btnMain{
  font-size:18px;
  font-weight:900;
}

.controls{
  min-width:0;
  min-height:0;
  display:grid;
  grid-template-rows:minmax(0,1fr) auto;
  gap:12px;
  padding-top:4px;
}

.controlCard{
  min-width:0;
  min-height:0;
  display:grid;
  gap:12px;
  padding:15px 15px 14px;
  border-radius:26px;
  border:1px solid rgba(17,46,88,.08);
  background:linear-gradient(180deg, rgba(255,255,255,.93), rgba(245,249,255,.84));
  box-shadow:var(--shadow-soft);
  backdrop-filter:blur(14px);
}

.collectionCard{
  grid-template-rows:auto auto auto auto minmax(0,1fr);
  align-content:start;
}

.navCard{
  align-content:start;
  gap:10px;
}

.cardSectionLabel{
  color:#5d77a0;
  font-size:10px;
  font-weight:900;
  letter-spacing:.14em;
}

.cardSectionTitle{
  margin:0;
  color:var(--accent-deep);
  font-family:var(--font-display);
  font-size:26px;
  font-weight:900;
  line-height:1.1;
}

.navCard .cardSectionTitle{
  font-size:22px;
}

.cardSectionCopy{
  margin:0;
  color:var(--text-soft);
  font-size:13px;
  line-height:1.62;
  font-weight:700;
}

.problemFilterRow{
  display:grid;
  grid-template-columns:repeat(3, minmax(0, 1fr));
  gap:8px;
}

.segmentBtn{
  min-width:0;
  min-height:46px;
  padding:0 11px;
  flex-direction:row;
  align-items:center;
  justify-content:space-between;
  border-radius:16px;
  border-color:rgba(17,46,88,.08);
  background:linear-gradient(180deg, rgba(255,255,255,.97), rgba(245,249,255,.86));
  color:#31507d;
  box-shadow:none;
}

.segmentBtn.is-active{
  color:#fff;
  background:linear-gradient(180deg, #2a72d8, #1a56b2);
  border-color:#184b9d;
  box-shadow:0 12px 20px rgba(28,84,168,.16);
}

.segmentCount{
  font-size:11px;
  font-weight:800;
  opacity:.78;
}

.problemUtilityRow{
  display:grid;
  gap:6px;
  padding:8px 10px 9px;
  border-radius:16px;
  border:1px solid rgba(17,46,88,.05);
  background:linear-gradient(180deg, rgba(246,250,255,.72), rgba(240,246,255,.58));
  box-shadow:inset 0 1px 0 rgba(255,255,255,.74);
}

.problemListSummary{
  display:none !important;
}

.sortGroup{
  display:grid;
  gap:5px;
}

.sortLabel{
  color:var(--text-faint);
  font-size:10px;
  font-weight:700;
  letter-spacing:.08em;
}

.sortSelect{
  appearance:none;
  width:100%;
  min-width:0;
  min-height:44px;
  padding:0 38px 0 12px;
  border-radius:15px;
  border:1px solid rgba(17,46,88,.10);
  background:
    rgba(255,255,255,.94)
    url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='8' viewBox='0 0 12 8'%3E%3Cpath fill='%23485c7d' d='M6 8 0 0h12z'/%3E%3C/svg%3E")
    no-repeat right 12px center / 12px 8px;
  color:#21416e;
  font-family:var(--font-ui);
  font-size:13px;
  font-weight:700;
}

.sortSelect:focus-visible{
  outline:none;
  border-color:rgba(31,102,204,.34);
  box-shadow:0 0 0 4px rgba(31,102,204,.12);
}

.sortAssist{
  color:var(--text-soft);
  font-size:11px;
  line-height:1.45;
  letter-spacing:.01em;
}

.metricRow{
  display:none !important;
}

.metricChip{
  display:none !important;
}

.metricValue{
  display:none !important;
}

.metricLabel{
  display:none !important;
}

.summaryNote{
  display:none !important;
}

.problemListEmpty{
  display:grid;
  place-items:center;
  min-height:72px;
  padding:16px 14px;
  border-radius:18px;
  border:1px dashed rgba(17,46,88,.18);
  background:rgba(255,255,255,.56);
  color:#6781a5;
  font-size:13px;
  font-weight:700;
}

.problemList{
  min-height:0;
  display:flex;
  flex-direction:column;
  gap:9px;
  overflow:auto;
  padding-top:2px;
  padding-right:2px;
  overscroll-behavior:contain;
  scrollbar-gutter:stable;
}

.problemList::-webkit-scrollbar{
  width:8px;
}

.problemList::-webkit-scrollbar-thumb{
  background:rgba(50,68,96,.18);
  border-radius:999px;
}

.problemCardButton{
  min-height:78px;
  display:grid;
  grid-template-columns:46px minmax(0,1fr) auto;
  align-items:center;
  gap:12px;
  padding:12px 12px;
  border-radius:20px;
  text-align:left;
  border-color:rgba(17,46,88,.06);
  background:linear-gradient(180deg, rgba(255,255,255,.96), rgba(245,249,255,.88));
  box-shadow:none;
}

.problemCardButton:hover:not(:disabled){
  border-color:rgba(28,84,168,.18);
  box-shadow:0 8px 16px rgba(27,68,132,.06);
}

.problemCardButton.is-current{
  background:linear-gradient(180deg, rgba(236,244,255,.98), rgba(228,238,255,.94));
  border-color:rgba(28,84,168,.22);
  box-shadow:0 10px 18px rgba(28,84,168,.08);
}

.problemCardIndex{
  display:grid;
  place-items:center;
  width:44px;
  height:44px;
  border-radius:15px;
  background:rgba(233,242,255,.98);
  color:var(--accent);
  font-size:13px;
  font-weight:900;
}

.problemCardButton.is-current .problemCardIndex{
  background:var(--accent);
  color:#fff;
}

.problemCardBody{
  min-width:0;
  display:grid;
  gap:5px;
}

.problemCardTitle{
  display:block;
  min-width:0;
  color:#15315e;
  font-size:15px;
  font-weight:900;
  line-height:1.4;
  white-space:nowrap;
  overflow:hidden;
  text-overflow:ellipsis;
}

.problemCardMeta{
  color:#6c84a7;
  font-size:12px;
  line-height:1.45;
}

.problemCardState{
  justify-self:end;
  padding:8px 10px;
  border-radius:999px;
  font-size:11px;
  font-weight:900;
  letter-spacing:.04em;
}

.problemCardState.unresolved{
  background:#f4ead6;
  color:#8a6525;
}

.problemCardState.solved{
  background:#e5f4eb;
  color:#25704c;
}

.modal{
  position:fixed;
  inset:0;
  z-index:60;
  display:none;
  align-items:center;
  justify-content:center;
  padding:18px;
  background:rgba(14,19,29,.34);
  backdrop-filter:blur(16px);
}

.modal.open{
  display:flex;
}

.modalCard{
  width:min(100%, 940px);
  max-height:min(90dvh, 900px);
  overflow:hidden;
  display:flex;
  flex-direction:column;
  border-radius:32px;
  border:1px solid rgba(255,255,255,.42);
  background:linear-gradient(180deg, rgba(252,254,255,.98), rgba(242,247,255,.97));
  box-shadow:0 30px 72px rgba(7,12,20,.22);
}

.confirmModalCard{
  width:min(100%, 580px);
  max-height:none;
}

.modalHead{
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:12px;
  padding:17px 20px;
  background:linear-gradient(180deg, #2358a2, #173f78);
}

.modalTitle{
  color:#fff;
  font-size:18px;
  font-weight:900;
}

.iconBtn{
  width:42px;
  height:42px;
  min-height:auto;
  padding:0;
  border-radius:999px;
  display:grid;
  place-items:center;
  border:1px solid rgba(255,255,255,.20);
  background:rgba(255,255,255,.12);
  color:#fff;
  box-shadow:none;
  font-size:22px;
  line-height:1;
}

.modalBody{
  flex:1 1 auto;
  min-height:0;
  overflow:auto;
  padding:18px;
  display:grid;
  gap:16px;
}

#explainModal .modalBody{
  grid-template-columns:minmax(280px, 360px) minmax(0,1fr);
  align-items:start;
}

.confirmModalBody{
  display:block;
}

.confirmCard,
.miniBoardWrap,
.explainCard{
  border-radius:24px;
  border:1px solid rgba(29,37,51,.08);
  background:linear-gradient(180deg, rgba(255,255,255,.86), rgba(245,249,255,.82));
  box-shadow:var(--shadow-card);
}

.confirmCard{
  position:relative;
  padding:24px;
  overflow:hidden;
}

.confirmCard::before{
  content:"";
  position:absolute;
  right:-36px;
  top:-28px;
  width:160px;
  height:160px;
  border-radius:999px;
  background:radial-gradient(circle, rgba(31,102,204,.16) 0%, rgba(31,102,204,0) 72%);
}

.confirmCard::after{
  content:"";
  position:absolute;
  left:-42px;
  bottom:-48px;
  width:180px;
  height:140px;
  border-radius:999px;
  background:radial-gradient(circle, rgba(221,235,255,.72) 0%, rgba(221,235,255,0) 72%);
}

.confirmLeadWrap,
.explainSectionHead{
  position:relative;
  z-index:1;
  display:flex;
  align-items:center;
  gap:10px;
  margin-bottom:14px;
}

.modalChip{
  display:inline-flex;
  align-items:center;
  justify-content:center;
  min-width:72px;
  padding:7px 12px;
  border-radius:999px;
  background:linear-gradient(180deg, #23508f, #173764);
  color:#fff;
  font-size:11px;
  font-weight:900;
  letter-spacing:.08em;
}

.confirmTone{
  color:var(--text-soft);
  font-size:12px;
  font-weight:700;
}

.confirmQuestion{
  position:relative;
  z-index:1;
  margin:0;
  color:#1a2332;
  font-family:var(--font-display);
  font-size:28px;
  font-weight:900;
  line-height:1.32;
  text-align:center;
}

.confirmMessage{
  position:relative;
  z-index:1;
  max-width:30em;
  margin:12px auto 0;
  color:#304255;
  font-size:16px;
  line-height:1.85;
  text-align:center;
}

.confirmAssist{
  position:relative;
  z-index:1;
  width:fit-content;
  margin:16px auto 0;
  padding:8px 12px;
  border-radius:999px;
  border:1px solid rgba(31,102,204,.10);
  background:rgba(31,102,204,.08);
  color:#5b6f8e;
  font-size:12px;
  font-weight:700;
}

.confirmActions{
  width:min(100%, 420px);
  margin:20px auto 0;
}

.miniBoardWrap{
  padding:16px;
}

.miniBoardShell{
  width:100%;
  max-width:360px;
  margin:0 auto;
  aspect-ratio:1 / 1;
  overflow:hidden;
  border-radius:22px;
  border:1px solid rgba(114,93,58,.28);
  background:#dfc48d;
  box-shadow:
    0 0 0 10px rgba(245,249,255,.94),
    0 0 0 13px rgba(198,214,237,.44),
    0 16px 28px rgba(36,74,128,.12);
}

.explainControl{
  margin-top:14px;
  display:grid;
  gap:10px;
}

.explainControlRow{
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:12px;
}

#explainVariantControls{
  justify-content:center;
  gap:10px;
  min-height:32px;
}

#explainVariantControls[hidden]{
  display:flex !important;
  visibility:hidden;
  pointer-events:none;
}

#explainVariantControls .explainStepBtn{
  min-width:108px;
}

.explainControlLabel,
.explainControlValue{
  color:#617080;
  font-size:12px;
  font-weight:800;
}

.explainRange{
  width:100%;
  accent-color:var(--accent);
}

.explainCard{
  padding:22px;
}

.explainLead{
  margin:0 0 12px;
  color:#5373a0;
  font-size:12px;
  font-weight:900;
  letter-spacing:.14em;
}

.explainText{
  color:#243447;
  font-size:16px;
  line-height:1.9;
}

#explainModal .modalHead{
  flex-wrap:wrap;
}

.explainModeSwitch{
  margin-left:auto;
  display:inline-flex;
  align-items:center;
  gap:6px;
  padding:5px;
  border-radius:999px;
  background:rgba(255,255,255,.10);
  border:1px solid rgba(255,255,255,.18);
  box-shadow:inset 0 1px 0 rgba(255,255,255,.08);
  backdrop-filter:blur(6px);
}

.explainModeSwitch[hidden]{
  display:none !important;
}

.explainModeBtn{
  min-height:34px;
  padding:0 14px;
  border-radius:999px;
  border:1px solid rgba(255,255,255,0);
  background:rgba(255,255,255,.04);
  color:rgba(255,255,255,.84);
  font-size:12px;
  font-weight:900;
  line-height:1;
  white-space:nowrap;
  box-shadow:none;
  transition:
    background-color .18s ease,
    border-color .18s ease,
    color .18s ease,
    box-shadow .18s ease;
  transform:none;
  -webkit-tap-highlight-color:transparent;
}

.explainModeBtn:active:not(:disabled){
  transform:none;
}

@media (hover:hover) and (pointer:fine){
  .explainModeBtn:hover:not(:disabled){
    background:rgba(255,255,255,.12);
    color:#fff;
  }
}

.explainModeBtn.is-active,
.explainModeBtn[aria-pressed="true"]{
  border-color:rgba(255,255,255,.28);
  background:linear-gradient(180deg,#fffdf8 0%,#f4ecdf 100%);
  color:#355270;
  box-shadow:
    inset 0 1px 0 rgba(255,255,255,.92),
    0 4px 12px rgba(16,37,68,.16);
}

.explainModeBtn:disabled{
  opacity:.45;
  cursor:default;
}

@media (min-width:961px){
  body{
    overflow:hidden;
  }

  .app{
    height:var(--app-dvh);
    grid-template-rows:auto minmax(0,1fr);
  }

  .stage{
    min-height:0;
  }

  .layout{
    height:100%;
  }

  .panel{
    height:100%;
    min-height:0;
  }

  .boardArea{
    height:100%;
  }

  .controls{
    height:100%;
    min-height:0;
  }
}

@media (max-width:1200px){
  :root{
    --rail-width:316px;
  }

  .boardArea{
    padding:18px 20px 16px;
  }

  .boardProblemTitle{
    font-size:clamp(32px, 3.7vw, 42px);
  }

  .cardSectionTitle{
    font-size:24px;
  }
}

@media (max-width:960px){
  .app{
    grid-template-rows:auto auto;
  }

  .topbar{
    padding:calc(8px + var(--safe-top)) 12px 6px;
  }

  .brandBand{
    grid-template-columns:1fr;
    gap:8px;
    padding:10px;
    border-radius:22px;
  }

  .logoWrap{
    min-height:78px;
    padding:8px 14px;
  }

  .brandCopy{
    gap:6px;
    max-width:none;
    padding:10px 12px;
  }

  .brandTitle{
    font-size:22px;
  }

  .brandLead{
    max-width:none;
    font-size:12px;
  }

  .stage{
    padding:0 12px calc(14px + var(--safe-bottom));
  }

  .panel{
    grid-template-columns:1fr;
    gap:12px;
  }

  .boardArea{
    padding:16px 16px 14px;
    border-radius:28px;
  }

  .boardStage{
    gap:12px;
  }

  .boardProblemTitle{
    font-size:31px;
  }

  .inlineHintText{
    font-size:16px;
  }

  .controls{
    grid-template-rows:none;
    gap:14px;
  }

  .controlCard{
    padding:14px 14px 13px;
    border-radius:22px;
  }

  .problemList{
    max-height:min(28dvh, 250px);
    overflow:auto;
    padding-right:2px;
    scrollbar-gutter:auto;
  }

  .navCard{
    order:1;
  }

  .collectionCard{
    order:2;
    grid-template-rows:auto auto auto auto minmax(0,1fr);
  }

  .collectionCard .cardSectionCopy,
  .collectionCard .summaryNote{
    display:none;
  }

  #explainModal .modalBody{
    grid-template-columns:1fr;
  }
}

@media (max-width:640px){
  .topbar{
    padding:calc(6px + var(--safe-top)) 10px 4px;
  }

  .brandBand{
    padding:8px;
    border-radius:20px;
  }

  .logoWrap{
    min-height:70px;
    padding:6px 12px;
    border-radius:18px;
  }

  .brandCopy{
    display:none;
    padding:8px 10px;
    border-radius:18px;
  }

  .brandEyebrow{
    font-size:9px;
    letter-spacing:.16em;
  }

  .brandTitle{
    font-size:22px;
  }

  .brandLead{
    font-size:12px;
  }

  .stage{
    padding:0 10px calc(14px + var(--safe-bottom));
  }

  .boardArea{
    padding:13px 11px 12px;
    border-radius:24px;
  }

  .boardStageTop{
    gap:12px;
  }

  .boardProblemTitle{
    font-size:28px;
  }

  .boardProblemMeta{
    font-size:13px;
  }

  .inlineHint{
    padding:11px 13px;
    border-radius:18px;
  }

  .inlineHintText{
    font-size:15px;
  }

  .boardActionRow,
  .navActionRow{
    grid-template-columns:1fr;
  }

  .controls{
    gap:10px;
  }

  .controlCard{
    padding:12px 11px 11px;
    border-radius:20px;
  }

  .cardSectionTitle{
    font-size:22px;
  }

  .navCard .cardSectionTitle{
    font-size:20px;
  }

  .cardSectionCopy,
  .sortAssist{
    font-size:12px;
  }

  .problemUtilityRow,
  .problemListSummary{
    padding:10px 12px;
  }

  .problemListSummary{
    display:none;
  }

  .problemList{
    max-height:min(24dvh, 192px);
    gap:8px;
  }

  .problemCardButton{
    grid-template-columns:42px minmax(0,1fr);
    min-height:72px;
  }

  .problemCardIndex{
    width:40px;
    height:40px;
  }

  .problemCardState{
    grid-column:2;
    justify-self:start;
  }

  .problemCardMeta{
    display:none;
  }

  .modal{
    padding:12px;
  }

  .modalCard{
    border-radius:24px;
  }

  .modalBody{
    padding:14px;
  }

  .confirmQuestion{
    font-size:24px;
  }

  .confirmMessage,
  .explainText{
    font-size:15px;
  }
}

@media (max-width:480px){
  body::before,
  body::after{
    display:none;
  }

  .brandCopy{
    display:none;
  }

  .logoWrap{
    min-height:64px;
  }

  .problemEyebrow{
    min-height:34px;
    font-size:10px;
  }

  .boardProblemTitle{
    font-size:24px;
  }

  .segmentBtn{
    min-height:46px;
    padding:0 10px;
    border-radius:14px;
    font-size:13px;
  }

  .segmentCount{
    font-size:10px;
  }

  .cardSectionCopy,
  .sortAssist,
  .btnSub{
    display:none;
  }

  .metricChip{
    padding:8px;
  }

  .metricValue{
    font-size:18px;
  }

  .metricLabel{
    font-size:11px;
  }

  .problemUtilityRow,
  .problemListSummary{
    padding:10px;
  }

  .problemList{
    max-height:min(22dvh, 168px);
  }
}

@media (pointer:coarse){
  .segmentBtn,
  .sortSelect,
  .problemCardButton,
  .boardActionRow button,
  .navActionRow button{
    min-height:60px;
  }

  .boardActionRow button,
  .navActionRow button{
    padding-top:16px;
    padding-bottom:14px;
  }

  .problemCardButton{
    padding-top:16px;
    padding-bottom:16px;
  }
}

@media (prefers-reduced-motion:reduce){
  *,
  *::before,
  *::after{
    animation-duration:.01ms !important;
    animation-iteration-count:1 !important;
    transition-duration:.01ms !important;
    scroll-behavior:auto !important;
  }
}


/* ===== header logo balance fix ===== */
.topbar{
  display:block;
  padding:calc(8px + var(--safe-top)) 18px 6px;
}

.brand{
  width:100%;
  max-width:1380px;
  margin:0 auto;
  display:flex;
  justify-content:center;
  align-items:center;
}

.brandBand{
  display:block;
  width:100%;
  padding:0;
  border:none;
  border-radius:0;
  background:transparent;
  box-shadow:none;
  overflow:visible;
}

.brandBand::before{
  content:none;
}

.brandCopy,
.brandDecor{
  display:none !important;
}

.logoWrap{
  width:min(100%,980px);
  max-width:980px;
  min-height:0;
  margin:0 auto;
  padding:0;
  border:none;
  border-radius:14px;
  background:transparent;
  box-shadow:none;
  overflow:hidden;
}

.logoWrap::before{
  content:none;
}

.brandLogoImg{
  display:block;
  width:100%;
  height:auto;
  max-width:100%;
  aspect-ratio:auto;
  border-radius:14px;
  object-fit:contain;
  box-shadow:none;
  filter:none;
}

@media (max-width:960px){
  .topbar{
    padding:calc(8px + var(--safe-top)) 12px 6px;
  }

  .logoWrap{
    width:100%;
    max-width:100%;
    border-radius:12px;
  }

  .brandLogoImg{
    border-radius:12px;
  }
}

@media (max-width:640px){
  .topbar{
    padding:calc(6px + var(--safe-top)) 10px 4px;
  }

  .logoWrap,
  .brandLogoImg{
    border-radius:10px;
  }
}


/* === 2026-04-02 requested tweak: restore logo display + make 第●問 10% smaller === */
.brand{
  justify-content:center !important;
}

.logoWrap{
  width:min(100%, 980px) !important;
  max-width:980px !important;
  min-height:0 !important;
  margin:0 auto !important;
  padding:0 !important;
  border:none !important;
  border-radius:14px !important;
  background:transparent !important;
  box-shadow:none !important;
  overflow:hidden !important;
}

.logoWrap::before{
  content:none !important;
}

.brandLogoImg{
  display:block !important;
  width:100% !important;
  height:auto !important;
  max-width:100% !important;
  max-height:none !important;
  border-radius:14px !important;
  box-shadow:none !important;
}

.boardProblemTitle{
  font-size:calc(clamp(34px, 3vw, 50px) * 0.9) !important;
}

@media (max-width: 1100px){
  .logoWrap{
    width:min(100%, 920px) !important;
    max-width:920px !important;
  }

  .boardProblemTitle{
    font-size:calc(clamp(30px, 5.6vw, 42px) * 0.9) !important;
  }
}

@media (max-width: 720px){
  .logoWrap{
    width:100% !important;
    max-width:100% !important;
    border-radius:10px !important;
  }

  .brandLogoImg{
    width:100% !important;
    border-radius:10px !important;
  }

  .boardProblemTitle{
    font-size:calc(clamp(28px, 8vw, 40px) * 0.9) !important;
  }
}