:root {
  color-scheme: light;
  --bg: #fbf7ef;
  --card: #ffffff;
  --ink: #2d2a26;
  --muted: #7a736a;
  --line: #e7dfd2;
  --accent: #f08c00;

  /* Montessori-Stempelspiel-Farben */
  --c-e: #2f9e44;
  --c-z: #1c7ed6;
  --c-h: #e03131;
  --c-t: #1b6e34;
  --t-e: #ebfbee;
  --t-z: #e7f5ff;
  --t-h: #fff0f0;
  --t-t: #e6f4ea;

  --cell: 10px;  /* Punktabstand, wird per JS pro Brett an die Breite angepasst */
  --hpr: 5;      /* Hunderter pro Zeile */
  --gap-z: 2px;
  --gap-h: 6px;
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }

html, body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: ui-rounded, "SF Pro Rounded", "Nunito", "Segoe UI", system-ui, sans-serif;
  -webkit-text-size-adjust: 100%;
}

body {
  padding: env(safe-area-inset-top) env(safe-area-inset-right) env(safe-area-inset-bottom) env(safe-area-inset-left);
}

button, input { font: inherit; color: inherit; }
button {
  touch-action: manipulation;
  -webkit-tap-highlight-color: transparent;
  cursor: pointer;
  user-select: none;
  -webkit-user-select: none;
}

/* ---------- Kopf ---------- */
.top {
  display: flex;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
  padding: 12px 16px;
  border-bottom: 1px solid var(--line);
  background: var(--card);
  position: sticky;
  top: 0;
  z-index: 10;
}
.top h1 { font-size: 1.3rem; margin: 0; display: flex; align-items: center; gap: 4px; }
.top h1 span { display: inline-block; width: 12px; height: 12px; border-radius: 50%; }
.top h1 .dot-e { background: var(--c-e); }
.top h1 .dot-z { background: var(--c-z); }
.top h1 .dot-h { background: var(--c-h); margin-right: 6px; }

.tabs { display: flex; gap: 6px; flex: 1; }
.tab {
  border: 0;
  background: transparent;
  padding: 10px 16px;
  border-radius: 999px;
  font-weight: 600;
  min-height: 44px;
  color: var(--muted);
}
.tab.active { background: var(--ink); color: #fff; }

.icon-btn {
  border: 1px solid var(--line);
  background: var(--card);
  width: 44px; height: 44px;
  border-radius: 50%;
  font-size: 1.2rem;
}
.icon-btn[aria-pressed="true"] { background: #fff4e0; border-color: var(--accent); }

main { padding: 16px; max-width: 1400px; margin: 0 auto; }
.panel { display: none; }
.panel.active { display: block; }

/* ---------- Bausteine ---------- */
.btn {
  border: 2px solid var(--ink);
  background: var(--card);
  border-radius: 14px;
  padding: 8px 16px;
  min-height: 48px;
  font-weight: 700;
  transition: transform .08s;
}
.btn:active { transform: scale(.96); }
.btn.primary { background: var(--ink); color: #fff; }
.btn.ghost { border-color: var(--line); }
.btn:disabled { opacity: .35; }

.seg { display: inline-flex; border: 2px solid var(--line); border-radius: 14px; overflow: hidden; }
.seg button { border: 0; background: var(--card); padding: 8px 14px; min-height: 44px; font-weight: 600; color: var(--muted); }
.seg button.active { background: var(--ink); color: #fff; }

.number-card { text-align: center; margin-bottom: 12px; }
.big-number { font-size: clamp(2.6rem, 7vw, 4.2rem); font-weight: 800; line-height: 1.05; letter-spacing: .02em; }
.number-word { font-size: 1.15rem; color: var(--muted); min-height: 1.4em; }
.decomp { margin-top: 6px; font-size: 1.15rem; min-height: 1.4em; }
.lbl { color: var(--muted); font-weight: 600; }

.toolbar, .task-row { display: flex; gap: 10px; flex-wrap: wrap; align-items: center; margin: 14px 0; }
.task-row.small { margin-top: 0; }
.task-row .sep { margin-left: 12px; }
.num-input { display: flex; align-items: center; gap: 8px; font-weight: 600; }
input[type=number] {
  width: 7ch;
  min-height: 48px;
  font-size: 1.4rem;
  font-weight: 700;
  text-align: center;
  border: 2px solid var(--line);
  border-radius: 14px;
  background: var(--card);
  -moz-appearance: textfield;
}
input[type=number]::-webkit-inner-spin-button,
input[type=number]::-webkit-outer-spin-button { -webkit-appearance: none; margin: 0; }
#r-a, #r-b { width: 6ch; font-size: 2rem; min-height: 60px; }
.op-switch { display: flex; flex-direction: column; gap: 4px; }
.op { border: 2px solid var(--line); background: var(--card); width: 48px; height: 32px; border-radius: 10px; font-size: 1.4rem; font-weight: 800; line-height: 1; }
.op.active { background: var(--ink); border-color: var(--ink); color: #fff; }
#r-go { min-height: 60px; font-size: 1.3rem; padding: 0 28px; }

.hint { color: var(--muted); max-width: 70ch; }
#legen-input { width: 6ch; }
.nowrap { display: inline-flex; align-items: center; gap: 10px; }
.cell.no-count { padding-bottom: 10px; }

/* Üben: Tastenfeld neben dem Brett, wenn Platz ist */
.erkennen-layout { display: grid; grid-template-columns: 1fr; gap: 16px; align-items: start; }
@media (min-width: 960px) {
  .erkennen-layout { grid-template-columns: 1fr 260px; }
  .erkennen-layout .answer-row { margin-top: 0; }
}
.check { display: inline-flex; align-items: center; gap: 6px; font-weight: 600; min-height: 44px; }
.check input { width: 22px; height: 22px; }

/* ---------- Brett (Stellenwerttafel mit Material) ---------- */
.board-wrap { overflow-x: auto; -webkit-overflow-scrolling: touch; padding-bottom: 4px; }
.board {
  --col-t: calc(var(--cell) * 10 + 34px);
  --col-h: calc(var(--cell) * 10 * var(--hpr) + (var(--hpr) - 1) * var(--gap-h) + 30px);
  --col-z: calc(var(--cell) * 20 + 18 * var(--gap-z) + 40px);
  --col-e: max(calc(var(--cell) * 2 + 34px), 120px);
  display: grid;
  gap: 6px;
  width: max-content;
  margin: 0 auto;
}
.col-head {
  text-align: center;
  border-radius: 12px 12px 4px 4px;
  padding: 4px 6px;
  color: #fff;
  font-weight: 800;
  line-height: 1.1;
}
.col-head b { font-size: 1.3rem; display: block; }
.col-head small { font-size: .75rem; font-weight: 600; opacity: .9; }
.head-t { background: var(--c-t); }
.head-h { background: var(--c-h); }
.head-z { background: var(--c-z); }
.head-e { background: var(--c-e); }

.row-label {
  display: flex; flex-direction: column; justify-content: center; align-items: flex-end;
  padding-right: 6px;
  font-weight: 800; font-size: 1.3rem;
  min-width: 64px;
}
.row-label small { font-size: .75rem; color: var(--muted); font-weight: 600; }

.cell {
  position: relative;
  border-radius: 6px;
  padding: 10px 10px 34px;
  min-height: calc(var(--cell) * 10 + 46px);
}
.cell-t { background: var(--t-t); }
.cell-h { background: var(--t-h); }
.cell-z { background: var(--t-z); }
.cell-e { background: var(--t-e); }
.board .focus.cell { box-shadow: inset 0 0 0 3px var(--accent); }
.board .focus.col-head { box-shadow: 0 0 0 3px var(--accent); }
.board .dim { opacity: .4; filter: saturate(.5); }
.board .cell, .board .col-head { transition: opacity .3s, filter .3s; }
.row-b .cell { background-image: repeating-linear-gradient(135deg, rgba(0,0,0,.025) 0 8px, transparent 8px 16px); }
.row-w .cell { opacity: .7; }

.count {
  position: absolute; left: 50%; bottom: 6px; transform: translateX(-50%);
  min-width: 30px; height: 24px; padding: 0 8px;
  border-radius: 12px;
  background: rgba(255,255,255,.85);
  font-weight: 800; text-align: center; line-height: 24px;
}
.count.over { background: var(--accent); color: #fff; animation: wobble .6s ease-in-out 2; }
.count.zero { color: var(--muted); }

.ctrl {
  display: flex; flex-wrap: wrap; gap: 6px; justify-content: center; align-content: flex-start;
}
.ctrl .pm { width: 52px; height: 52px; border-radius: 14px; border: 2px solid; background: var(--card); font-size: 1.8rem; font-weight: 800; line-height: 1; }
.ctrl-t .pm { border-color: var(--c-t); color: var(--c-t); }
.ctrl-h .pm { border-color: var(--c-h); color: var(--c-h); }
.ctrl-z .pm { border-color: var(--c-z); color: var(--c-z); }
.ctrl-e .pm { border-color: var(--c-e); color: var(--c-e); }
.ctrl .xch { width: 100%; min-height: 40px; border-radius: 12px; border: 2px dashed var(--line); background: var(--card); font-size: .85rem; font-weight: 700; color: var(--muted); }
.ctrl .xch.go { border-color: var(--accent); color: var(--accent); border-style: solid; animation: wobble .6s ease-in-out 2; }
.ctrl .xch:disabled { visibility: hidden; }

/* ---------- Material ---------- */
.pieces { display: flex; flex-wrap: wrap; align-content: flex-start; }
.pieces-h { gap: var(--gap-h); }
.pieces-z { gap: 10px; }
.pieces-z .group { display: flex; gap: var(--gap-z); }
.pieces-e {
  display: grid;
  grid-template-rows: repeat(10, var(--cell));
  grid-auto-flow: column;
  grid-auto-columns: var(--cell);
  column-gap: 6px;
  justify-content: center;
}
.pieces-t { justify-content: center; }

.piece {
  --c: var(--c-e);
  position: relative;
  background-image: radial-gradient(circle at center, var(--c) 0 33%, transparent 38%);
  background-size: var(--cell) var(--cell);
  transition: transform .35s ease, opacity .35s ease;
}
.piece-e { --c: var(--c-e); width: var(--cell); height: var(--cell); background-image: radial-gradient(circle at center, var(--c) 0 40%, transparent 46%); }
.piece-z, .piece-h {
  border-radius: 3px;
  outline: 1.5px solid color-mix(in srgb, var(--c) 55%, transparent);
  outline-offset: 0;
  background-color: rgba(255,255,255,.7);
}
.piece-z { --c: var(--c-z); width: var(--cell); height: calc(var(--cell) * 10); }
.piece-h { --c: var(--c-h); width: calc(var(--cell) * 10); height: calc(var(--cell) * 10); }
.piece-t {
  --c: var(--c-t);
  width: calc(var(--cell) * 10); height: calc(var(--cell) * 10);
  background-color: #fff;
  border-radius: 3px;
  outline: 1.5px solid var(--c);
  box-shadow: 3px -3px 0 #fff, 3px -3px 0 1.5px var(--c), 6px -6px 0 #fff, 6px -6px 0 1.5px var(--c), 9px -9px 0 #fff, 9px -9px 0 1.5px var(--c);
  margin: 10px 10px 0 0;
  display: grid; place-items: center;
}
.piece-t span { background: var(--c); color: #fff; font-weight: 800; padding: 2px 6px; border-radius: 6px; font-size: .9rem; }

/* Markierungen in den Rechenschritten */
.m-remove { opacity: .45; }
.m-remove::after {
  content: "";
  position: absolute; inset: -2px;
  background:
    linear-gradient(45deg, transparent calc(50% - 1.5px), #c92a2a calc(50% - 1.5px) calc(50% + 1.5px), transparent calc(50% + 1.5px)),
    linear-gradient(-45deg, transparent calc(50% - 1.5px), #c92a2a calc(50% - 1.5px) calc(50% + 1.5px), transparent calc(50% + 1.5px));
  border-radius: 3px;
}
.piece-e.m-remove::after { inset: -1px; }
.m-exchange { box-shadow: 0 0 0 3px #ffd43b, 0 0 12px 3px #fab005; animation: pulse 1s ease-in-out infinite; z-index: 1; }
.piece-e.m-exchange { border-radius: 50%; }
.m-new { animation: pop .55s ease-out; box-shadow: 0 0 0 2px #ffd43b; }
.piece-e.m-new { border-radius: 50%; }
.m-move { box-shadow: 0 0 0 3px #ffd43b; animation: nudge 1s ease-in-out infinite; }
.piece-e.m-move { border-radius: 50%; }
.leaving { transform: scale(0) !important; opacity: 0 !important; }
.leaving-up { transform: translateY(-60px) !important; opacity: 0 !important; }

@keyframes pop { 0% { transform: scale(0); } 70% { transform: scale(1.15); } 100% { transform: scale(1); } }
@keyframes pulse { 50% { transform: scale(1.06); } }
@keyframes nudge { 50% { transform: translateY(-6px); } }
@keyframes wobble { 25% { transform: translateX(-50%) rotate(-6deg); } 75% { transform: translateX(-50%) rotate(6deg); } }
.ctrl .xch.go { animation-name: wobble2; }
@keyframes wobble2 { 25% { transform: rotate(-2deg); } 75% { transform: rotate(2deg); } }
@keyframes shake { 20%, 60% { transform: translateX(-6px); } 40%, 80% { transform: translateX(6px); } }
.shake { animation: shake .4s; }

/* ---------- Rechnen ---------- */
.calc-layout { display: grid; grid-template-columns: minmax(220px, 280px) 1fr; gap: 16px; align-items: start; }
.calc-side { background: var(--card); border: 1px solid var(--line); border-radius: 18px; padding: 14px; position: sticky; top: 84px; }
.calc-main { min-width: 0; }

.equation { font-size: 1.8rem; font-weight: 800; text-align: center; margin-bottom: 10px; }
.equation .res { color: var(--accent); }

.tafel { border-collapse: collapse; margin: 0 auto 12px; font-size: 1.5rem; font-weight: 800; }
.tafel th { font-size: .95rem; color: #fff; padding: 4px 10px; }
.tafel th.t { background: var(--c-t); } .tafel th.h { background: var(--c-h); }
.tafel th.z { background: var(--c-z); } .tafel th.e { background: var(--c-e); }
.tafel th:first-child { background: transparent; }
.tafel td { text-align: center; min-width: 46px; height: 44px; border: 1px solid var(--line); }
.tafel td:first-child { border: 0; color: var(--muted); padding-right: 6px; text-align: right; min-width: 0; }
.tafel tr.result td { border-top: 3px solid var(--ink); }
.tafel tr.result td:first-child { border-top: 0; }
.tafel td.now {
  background: #ffec99;
  color: var(--ink);
  box-shadow: inset 3px 0 0 var(--accent), inset -3px 0 0 var(--accent);
  font-size: 1.15em;
}
.tafel tr.result td.now { box-shadow: inset 3px 0 0 var(--accent), inset -3px 0 0 var(--accent), inset 0 -3px 0 var(--accent); }
.tafel th.now { box-shadow: 0 0 0 3px var(--accent); position: relative; z-index: 1; }
.tafel td, .tafel th { transition: background .3s, opacity .3s; }
.tafel td.fresh { animation: pop .5s; color: var(--accent); }

.log { margin: 0; padding-left: 22px; font-size: 1rem; line-height: 1.6; }
.log li:last-child { font-weight: 700; }

.bubble {
  background: var(--card);
  border: 2px solid var(--ink);
  border-radius: 20px;
  padding: 14px 18px;
  min-height: 92px;
  margin-bottom: 10px;
  position: relative;
}
.step-count { font-size: .85rem; color: var(--muted); font-weight: 700; }
.step-text { font-size: clamp(1.15rem, 2.2vw, 1.5rem); font-weight: 600; line-height: 1.35; }
.step-text .k-t { color: var(--c-t); } .step-text .k-h { color: var(--c-h); }
.step-text .k-z { color: var(--c-z); } .step-text .k-e { color: var(--c-e); }
.bubble.final { border-color: var(--accent); background: #fff8eb; }
.step-nav { display: flex; gap: 10px; margin-bottom: 12px; flex-wrap: wrap; }
.step-nav .btn { flex: 1; min-width: 120px; }

/* ---------- Üben ---------- */
.stars { margin-left: auto; font-size: 1.4rem; font-weight: 800; }
.answer-row { display: flex; flex-direction: column; align-items: center; gap: 8px; margin: 14px 0 12px; text-align: center; }
.answer {
  min-width: 5ch; min-height: 64px;
  font-size: 2.6rem; font-weight: 800; text-align: center;
  border-bottom: 4px solid var(--ink);
  padding: 0 10px;
}
.feedback { font-size: 1.2rem; font-weight: 700; min-height: 1.5em; }
.feedback.ok { color: var(--c-e); }
.feedback.no { color: var(--c-h); }
.keypad { display: grid; grid-template-columns: repeat(3, 76px); gap: 10px; justify-content: center; }
.keypad button { height: 64px; border-radius: 16px; border: 2px solid var(--line); background: var(--card); font-size: 1.7rem; font-weight: 800; }
.keypad button:active { transform: scale(.95); }
.keypad .ok { background: var(--ink); color: #fff; border-color: var(--ink); }

.celebrate { position: fixed; inset: 0; pointer-events: none; z-index: 50; overflow: hidden; }
.celebrate span { position: absolute; top: -40px; font-size: 2rem; animation: fall 1.6s ease-in forwards; }
@keyframes fall { to { transform: translateY(110vh) rotate(360deg); } }

/* ---------- Kopfrechnen ---------- */
.k-card { background: var(--card); border: 1px solid var(--line); border-radius: 20px; padding: 20px 24px; max-width: 640px; margin: 0 auto; text-align: center; }
.k-card h2 { margin: 0 0 4px; font-size: 1.6rem; }
.k-card .hint { margin: 0 auto 16px; }
.k-opt { display: flex; flex-direction: column; align-items: center; gap: 6px; margin-bottom: 14px; }
.seg.multi { border: 0; gap: 8px; overflow: visible; flex-wrap: wrap; justify-content: center; }
.seg.multi button { border: 2px solid var(--line); border-radius: 14px; min-width: 110px; }
.seg.multi button.active { background: var(--c-z); border-color: var(--c-z); }
.seg.multi button.active::before { content: '✓ '; }
.k-record { min-height: 1.4em; font-weight: 700; color: var(--muted); margin: 6px 0 12px; }
.k-start { font-size: 1.4rem; min-height: 64px; padding: 0 40px; }
.toolbar.center { justify-content: center; }

.k-top { display: flex; align-items: center; gap: 14px; margin-bottom: 18px; }
.k-time { font-size: 1.8rem; font-weight: 800; font-variant-numeric: tabular-nums; min-width: 3.2ch; }
.k-bar { flex: 1; height: 18px; border-radius: 9px; background: var(--line); overflow: hidden; }
#k-bar-fill { height: 100%; width: 100%; background: var(--c-e); border-radius: 9px; transition: width .2s linear, background .3s; }
.k-top.hurry #k-bar-fill { background: var(--accent); }
.k-top.hurry .k-time { color: var(--c-h); }
.k-score { font-size: 1.6rem; font-weight: 800; font-variant-numeric: tabular-nums; }

.k-play { display: grid; grid-template-columns: 1fr; gap: 20px; align-items: center; }
@media (min-width: 900px) { .k-play { grid-template-columns: 1fr 260px; } }
.k-task-wrap { text-align: center; }
.k-task { font-size: clamp(2.8rem, 9vw, 5rem); font-weight: 800; font-variant-numeric: tabular-nums; white-space: nowrap; }
.k-task .ans { display: inline-block; min-width: 2.2ch; border-bottom: 5px solid var(--ink); color: var(--c-z); text-align: center; }
.k-task.ok .ans { color: var(--c-e); border-color: var(--c-e); }
.k-task.no { animation: shake .4s; }
.k-task.no .ans { color: var(--c-h); border-color: var(--c-h); }
#k-skip { margin-top: 10px; }

.k-res-big { font-size: 3.4rem; font-weight: 800; color: var(--c-e); }
.k-res-detail { font-size: 1.15rem; margin-bottom: 12px; }
.k-res-detail .rec { color: var(--accent); font-weight: 800; }
.k-wrong { display: flex; flex-wrap: wrap; gap: 8px; justify-content: center; margin-bottom: 8px; }
.k-wrong span { background: var(--t-h); border-radius: 10px; padding: 6px 10px; font-weight: 700; }

/* ---------- schmal (iPad hochkant / Handy) ---------- */
@media (max-width: 900px) {
  .calc-layout { grid-template-columns: 1fr; }
  .calc-side { position: static; display: grid; grid-template-columns: auto auto; gap: 12px; align-items: start; }
  .calc-side .equation { grid-column: 1 / -1; }
  .tafel { margin: 0; }
}
@media (max-width: 560px) {
  .top h1 { font-size: 1.05rem; }
  .tab { padding: 8px 10px; }
  .calc-side { grid-template-columns: 1fr; }
  .tafel { margin: 0 auto; }
  .task-row .sep { margin-left: 0; }
}
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation: none !important; transition: none !important; }
}