:root{
  --bg: #0b1020;
  --panel: rgba(255,255,255,.06);
  --panel2: rgba(255,255,255,.09);
  --stroke: rgba(255,255,255,.12);
  --text: rgba(255,255,255,.92);
  --muted: rgba(255,255,255,.65);
  --accent: #7c5cff;
  --accent2: #38bdf8;
  --good: #22c55e;
  --bad: #fb7185;
  --warn: #fbbf24;

  --cell: 54px;
  --radius: 18px;
  --shadow: 0 18px 55px rgba(0,0,0,.55);
  --blur: blur(14px);
}

*{ box-sizing:border-box; }
html,body{ height:100%; }
body{
  margin:0;
  font-family: ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, "Apple Color Emoji","Segoe UI Emoji";
  background:
    radial-gradient(900px 500px at 10% 0%, rgba(124,92,255,.35), transparent 60%),
    radial-gradient(900px 600px at 85% 10%, rgba(56,189,248,.25), transparent 55%),
    radial-gradient(900px 700px at 50% 100%, rgba(34,197,94,.12), transparent 60%),
    var(--bg);
  color: var(--text);
  overflow-x:hidden;
}

.app{
  max-width: 1200px;
  margin: 0 auto;
  padding: 24px 20px 40px;
}

.topbar{
  display:flex;
  gap:18px;
  align-items:center;
  justify-content:space-between;
  padding: 16px 18px;
  border:1px solid var(--stroke);
  background: linear-gradient(180deg, rgba(255,255,255,.08), rgba(255,255,255,.04));
  backdrop-filter: var(--blur);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.brand{ display:flex; gap:14px; align-items:center; }
.logo{
  width:44px;height:44px;border-radius:14px;
  display:grid; place-items:center;
  background: radial-gradient(circle at 30% 30%, rgba(124,92,255,.9), rgba(56,189,248,.25));
  border:1px solid rgba(255,255,255,.18);
  box-shadow: 0 12px 28px rgba(124,92,255,.25);
  font-size: 18px;
}
.title{ font-weight:800; letter-spacing:.3px; font-size: 18px; }
.subtitle{ color: var(--muted); font-size: 13px; margin-top:2px; }

.hud{ display:flex; align-items:center; gap:10px; flex-wrap:wrap; justify-content:flex-end; }
.pill{
  display:flex; gap:10px; align-items:center;
  padding: 10px 12px;
  border-radius: 999px;
  background: rgba(255,255,255,.06);
  border: 1px solid var(--stroke);
}
.pillLabel{ color: var(--muted); font-size: 12px; }
.select{
  color: var(--text);
  background: rgba(0,0,0,.25);
  border: 1px solid rgba(255,255,255,.14);
  border-radius: 999px;
  padding: 8px 10px;
  outline:none;
}

.btn{
  color: var(--text);
  background: rgba(255,255,255,.06);
  border:1px solid var(--stroke);
  padding: 10px 12px;
  border-radius: 14px;
  cursor:pointer;
  transition: transform .12s ease, background .2s ease, border-color .2s ease, box-shadow .2s ease;
  user-select:none;
}
.btn:hover{
  background: rgba(255,255,255,.09);
  transform: translateY(-1px);
}
.btn:active{ transform: translateY(0px) scale(.98); }
.btn.primary{
  background: linear-gradient(135deg, rgba(124,92,255,.95), rgba(56,189,248,.75));
  border-color: rgba(255,255,255,.22);
  box-shadow: 0 14px 30px rgba(124,92,255,.22);
}
.btn.primary:hover{ box-shadow: 0 18px 40px rgba(124,92,255,.28); }

.content{
  margin-top: 18px;
  display:grid;
  grid-template-columns: 1fr 320px;
  gap: 18px;
}

.boardWrap{
  border-radius: var(--radius);
  border:1px solid var(--stroke);
  background: linear-gradient(180deg, rgba(255,255,255,.06), rgba(255,255,255,.03));
  backdrop-filter: var(--blur);
  box-shadow: var(--shadow);
  padding: 18px;
}

.board{
  width: calc(var(--cell) * 9 + 10px);
  max-width: 100%;
  margin: 0 auto;
  display:grid;
  grid-template-columns: repeat(9, var(--cell));
  grid-template-rows: repeat(9, var(--cell));
  gap: 0;
  border-radius: 18px;
  overflow:hidden;
  border: 1px solid rgba(255,255,255,.16);
  background: rgba(0,0,0,.22);
  position:relative;
}

.cell{
  position:relative;
  display:grid;
  place-items:center;
  border: 1px solid rgba(255,255,255,.08);
  cursor:pointer;
  outline:none;
  user-select:none;
  transform: translateZ(0);
  transition: background .18s ease, transform .14s ease, box-shadow .18s ease;
}
.cell::before{
  content:"";
  position:absolute; inset:0;
  background:
    radial-gradient(circle at 30% 25%, rgba(255,255,255,.06), transparent 45%);
  opacity:.0;
  transition: opacity .2s ease;
}
.cell:hover::before{ opacity: .9; }

.cell.given{
  cursor: default;
  background: rgba(255,255,255,.035);
}
.cell.given .value{ opacity:.88; }

.value{
  font-size: 22px;
  font-weight: 800;
  letter-spacing: .2px;
  text-shadow: 0 10px 22px rgba(0,0,0,.45);
  transition: transform .16s ease, color .18s ease, opacity .18s ease;
}
.cell.filled .value{
  animation: pop .12s ease;
}
@keyframes pop{
  from{ transform: scale(.92); }
  to{ transform: scale(1); }
}

.notes{
  position:absolute;
  inset: 6px;
  display:grid;
  grid-template-columns: repeat(3, 1fr);
  grid-template-rows: repeat(3, 1fr);
  gap: 2px;
  font-size: 10px;
  color: rgba(255,255,255,.7);
  opacity: .9;
  pointer-events:none;
}
.note{
  display:grid; place-items:center;
  transform: scale(.98);
  opacity: .0;
  transition: opacity .12s ease, transform .12s ease;
}
.note.on{ opacity: 1; transform: scale(1); }

.cell.selected{
  background: rgba(124,92,255,.22);
  box-shadow: inset 0 0 0 2px rgba(124,92,255,.55);
}
.cell.related{
  background: rgba(255,255,255,.06);
}
.cell.same{
  background: rgba(56,189,248,.16);
}
.cell.error{
  background: rgba(251,113,133,.18);
  box-shadow: inset 0 0 0 2px rgba(251,113,133,.55);
  animation: shake .22s ease;
}
@keyframes shake{
  0%{ transform: translateX(0); }
  25%{ transform: translateX(-2px); }
  50%{ transform: translateX(2px); }
  75%{ transform: translateX(-1px); }
  100%{ transform: translateX(0); }
}

.cell.blockBorderR{ border-right-color: rgba(255,255,255,.18); }
.cell.blockBorderB{ border-bottom-color: rgba(255,255,255,.18); }

.toolbar{
  display:flex;
  gap:10px;
  flex-wrap:wrap;
  justify-content:center;
  margin: 14px auto 0;
}

.toggle{
  display:flex;
  align-items:center;
  gap:10px;
  padding: 10px 12px;
  border-radius: 14px;
  background: rgba(255,255,255,.06);
  border:1px solid var(--stroke);
  user-select:none;
}
.toggle input{ display:none; }
.toggleUi{
  width: 44px; height: 24px;
  background: rgba(255,255,255,.10);
  border:1px solid rgba(255,255,255,.14);
  border-radius: 999px;
  position:relative;
  transition: background .2s ease;
}
.toggleUi::after{
  content:"";
  position:absolute;
  width: 18px; height: 18px;
  border-radius: 999px;
  top: 2px; left: 2px;
  background: rgba(255,255,255,.85);
  box-shadow: 0 10px 20px rgba(0,0,0,.35);
  transition: transform .2s ease, background .2s ease;
}
.toggleText{ color: var(--muted); font-size: 13px; }
.toggle input:checked + .toggleUi{
  background: rgba(124,92,255,.35);
}
.toggle input:checked + .toggleUi::after{
  transform: translateX(20px);
  background: rgba(255,255,255,.95);
}

.keypad{
  margin-top: 14px;
  display:grid;
  grid-template-columns: repeat(9, 1fr);
  gap: 10px;
}
.key{
  padding: 12px 0;
  border-radius: 16px;
  background: rgba(255,255,255,.06);
  border:1px solid var(--stroke);
  color: var(--text);
  font-weight:800;
  cursor:pointer;
  transition: transform .12s ease, background .2s ease, box-shadow .2s ease;
}
.key:hover{ background: rgba(255,255,255,.10); transform: translateY(-1px); }
.key:active{ transform: translateY(0) scale(.98); }

.side{ display:flex; flex-direction:column; gap: 14px; }
.card{
  border-radius: var(--radius);
  border:1px solid var(--stroke);
  background: linear-gradient(180deg, rgba(255,255,255,.06), rgba(255,255,255,.03));
  backdrop-filter: var(--blur);
  box-shadow: var(--shadow);
  padding: 14px 14px 16px;
}
.cardTitle{ font-weight:800; margin-bottom:10px; }
.cardBody{ color: var(--text); }
.cardBody.subtle{ color: var(--muted); line-height: 1.45; }

.list{ margin:0; padding-left: 18px; color: var(--muted); }
kbd{
  background: rgba(0,0,0,.35);
  border:1px solid rgba(255,255,255,.16);
  border-bottom-color: rgba(255,255,255,.28);
  border-radius: 8px;
  padding: 2px 6px;
  font-size: 12px;
  color: rgba(255,255,255,.85);
}

.toast{
  min-height: 42px;
  padding: 12px 14px;
  border-radius: 16px;
  border:1px solid rgba(255,255,255,.14);
  background: rgba(0,0,0,.28);
  color: rgba(255,255,255,.86);
  opacity: 0;
  transform: translateY(8px);
  transition: opacity .22s ease, transform .22s ease;
}
.toast.show{
  opacity: 1;
  transform: translateY(0px);
}
.toast.good{ border-color: rgba(34,197,94,.35); }
.toast.bad{ border-color: rgba(251,113,133,.35); }
.toast.warn{ border-color: rgba(251,191,36,.35); }

.overlay{
  position:fixed; inset:0;
  display:grid; place-items:center;
  background: rgba(0,0,0,.55);
  backdrop-filter: blur(10px);
  z-index: 50;
  animation: fadeIn .18s ease;
}
@keyframes fadeIn{
  from{ opacity: 0; }
  to{ opacity: 1; }
}
.modal{
  width: min(520px, calc(100vw - 32px));
  border-radius: 22px;
  border:1px solid rgba(255,255,255,.16);
  background: linear-gradient(180deg, rgba(255,255,255,.10), rgba(255,255,255,.06));
  box-shadow: 0 30px 80px rgba(0,0,0,.6);
  padding: 18px 18px 16px;
  position:relative;
  overflow:hidden;
}
.modalTitle{
  font-weight: 900;
  font-size: 22px;
  letter-spacing:.2px;
}
.modalText{ color: var(--muted); margin-top: 8px; }
.modalActions{
  display:flex; gap:10px;
  justify-content:flex-end;
  margin-top: 14px;
}

/* confetti-ish stripes */
.confetti{
  position:absolute; inset:-40px -60px auto -60px;
  height: 160px;
  background:
    repeating-linear-gradient(110deg,
      rgba(124,92,255,.0) 0 12px,
      rgba(124,92,255,.25) 12px 24px,
      rgba(56,189,248,.0) 24px 36px,
      rgba(56,189,248,.22) 36px 48px,
      rgba(34,197,94,.0) 48px 60px,
      rgba(34,197,94,.20) 60px 72px
    );
  filter: blur(0px);
  opacity: .9;
  transform: rotate(-8deg);
  animation: slide 2.6s ease-in-out infinite;
}
@keyframes slide{
  0%,100%{ transform: translateX(-20px) rotate(-8deg); opacity:.85; }
  50%{ transform: translateX(20px) rotate(-8deg); opacity:1; }
}

@media (max-width: 980px){
  .content{ grid-template-columns: 1fr; }
  .side{ order: 2; }
  :root{ --cell: 46px; }
  .board{ width: calc(var(--cell) * 9 + 10px); }
}

@media (max-width: 440px){
  :root{ --cell: 40px; }
  .keypad{ grid-template-columns: repeat(9, 1fr); gap: 8px; }
  .btn, .toggle{ padding: 9px 10px; border-radius: 14px; }
}

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