:root {
  --bg: #f8f6fd; --card: #fff; --ink: #2b2445; --muted: #6b6485; --line: #e6e0f3;
  --lilac: #d9cdf5; --lilac-d: #6d4fc2; --mint: #cdeedb; --mint-d: #2a7f52;
  --ok: #2a7f52; --bad: #c2415b; --c: #6d4fc2; --t: #e7defa; --r: 16px;
}
* { box-sizing: border-box; }
body { margin: 0; font: 17px/1.6 system-ui, -apple-system, "Segoe UI", sans-serif; color: var(--ink); background: var(--bg); }
a { color: inherit; text-decoration: none; }
main { max-width: 980px; margin: 0 auto; padding: 24px 16px 60px; }

/* Kopfzeile */
.top { position: sticky; top: 0; z-index: 10; display: flex; flex-wrap: wrap; gap: 8px 20px; align-items: center; padding: 10px 20px; background: linear-gradient(90deg, var(--lilac), var(--mint)); color: #2b2445; box-shadow: 0 2px 8px rgba(80, 60, 140, .12); }
.brand { font-weight: 800; font-size: 1.2rem; letter-spacing: .01em; }
#gradenav { display: flex; gap: 6px; flex-wrap: wrap; }
#gradenav a { padding: 4px 14px; border-radius: 999px; font-size: .93rem; background: rgba(255,255,255,.65); }
#gradenav a:hover { background: #fff; }
#gradenav a.on { background: var(--c); color: #fff; }
footer { text-align: center; color: var(--muted); font-size: .85rem; padding: 24px 16px 40px; }

/* Startseite */
.hero { background: linear-gradient(135deg, var(--lilac), var(--mint)); color: #2b2445; border-radius: 24px; padding: 40px 28px; }
.hero h1 { margin: 0 0 12px; font-size: clamp(1.8rem, 5vw, 2.7rem); line-height: 1.15; }
.hero h1 span { font-size: .55em; font-weight: 600; color: #4b3a86; }
.hero p { max-width: 640px; margin: 0 0 18px; }
.stats { display: flex; gap: 10px; flex-wrap: wrap; }
.stats span { background: rgba(255,255,255,.7); padding: 6px 14px; border-radius: 999px; font-size: .95rem; }
.sec { margin: 34px 0 14px; font-size: 1.3rem; }
.grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(270px, 1fr)); gap: 16px; }
.gcard { display: flex; gap: 16px; align-items: center; background: var(--card); border-radius: var(--r); padding: 18px; border: 2px solid transparent; box-shadow: 0 1px 4px rgba(80,60,140,.08); transition: .15s; }
.gcard:hover { border-color: var(--c); transform: translateY(-2px); box-shadow: 0 8px 20px rgba(80,60,140,.14); }
.gnum { flex: none; width: 64px; height: 64px; border-radius: 18px; background: var(--t); color: var(--c); font-size: 2rem; font-weight: 800; display: grid; place-items: center; }
.gcard h3 { margin: 0; }
.gcard p { margin: 2px 0 8px; color: var(--muted); font-size: .92rem; line-height: 1.4; }
.gcard small { color: var(--muted); font-size: .8rem; }
.bar { height: 6px; background: var(--line); border-radius: 6px; overflow: hidden; margin-bottom: 4px; }
.bar i { display: block; height: 100%; background: var(--c); }
.steps { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 16px; }
.steps div { background: var(--card); border-radius: var(--r); padding: 18px; }
.steps div:nth-child(odd) b { background: var(--lilac-d); } .steps div:nth-child(even) b { background: var(--mint-d); }
.steps b { display: inline-grid; place-items: center; width: 32px; height: 32px; border-radius: 50%; color: #fff; }
.steps h4 { margin: 8px 0 2px; } .steps p { margin: 0; color: var(--muted); font-size: .95rem; }

/* Klassenseite */
.crumbs { color: var(--muted); font-size: .9rem; margin-bottom: 14px; }
.crumbs a { color: var(--c); text-decoration: underline; }
.ghead { display: flex; justify-content: space-between; align-items: center; gap: 12px; flex-wrap: wrap; background: var(--t); border: 2px solid var(--c); border-radius: 24px; padding: 22px 28px; margin-bottom: 8px; }
.ghead h1 { margin: 0; color: var(--c); } .ghead p { margin: 4px 0 0; }
.area h2 { margin: 28px 0 10px; font-size: 1.15rem; }
.tlist { display: grid; gap: 8px; }
.topic { display: flex; justify-content: space-between; align-items: center; gap: 10px; flex-wrap: wrap; background: var(--card); border-left: 8px solid var(--t); border-radius: 12px; padding: 12px 16px; box-shadow: 0 1px 3px rgba(80,60,140,.08); }
a.topic { border-left-color: var(--c); }
a.topic:hover { transform: translateX(3px); box-shadow: 0 4px 14px rgba(80,60,140,.15); }
.topic.soon { color: var(--muted); background: #f0edf7; box-shadow: none; }
.tt { font-weight: 600; }
.topic.soon .tt { font-weight: 400; }
.tags { display: flex; gap: 6px; }
.tag { font-style: normal; font-size: .78rem; padding: 2px 10px; border-radius: 999px; background: var(--line); color: var(--muted); white-space: nowrap; }
.tag.sim { background: var(--lilac); color: #4b3a86; }
.tag.ok { background: var(--mint); color: #1e6b41; }
.tag.part { background: #fdf0c9; color: #8a6414; }

/* Themenseite */
.topicpage header { background: var(--card); border-radius: 20px; padding: 24px 26px; border-top: 8px solid var(--c); }
.topicpage header small { color: var(--c); font-weight: 700; }
.topicpage h1 { margin: 2px 0 8px; font-size: clamp(1.5rem, 4vw, 2.1rem); line-height: 1.2; }
.intro { margin: 0; font-size: 1.05rem; color: #443d63; }
.block { background: var(--card); border-radius: var(--r); padding: 4px 24px 12px; margin-top: 16px; overflow-x: auto; }
.block h2 { font-size: 1.2rem; color: var(--c); }
.block p, .block li { margin: .5em 0; }
table.t { border-collapse: collapse; width: 100%; font-size: .95rem; margin: 10px 0; }
table.t th { background: var(--t); text-align: left; }
table.t th, table.t td { padding: 6px 10px; border-bottom: 1px solid var(--line); }
.merke { margin-top: 16px; display: flex; gap: 12px; background: #fdf3cf; border-left: 6px solid #e5b93c; border-radius: 12px; padding: 14px 18px; }
.merke b { flex: none; }
.formel { margin-top: 16px; background: var(--t); border: 2px solid var(--c); border-radius: 14px; padding: 14px; text-align: center; }
.formel .f { font-size: 1.6rem; font-weight: 600; font-family: Georgia, "Times New Roman", serif; }
.formel .fn { color: #4a4368; font-size: .92rem; margin-top: 8px; }
.formel .f { font-size: 1.7rem; padding: 4px 0 8px; }
table.legend { margin: 6px auto 0; border-collapse: separate; border-spacing: 0; background: #fff; border-radius: 10px; overflow: hidden; font-size: .93rem; text-align: left; box-shadow: 0 0 0 1px var(--line); }
table.legend th { background: var(--c); color: #fff; font-weight: 600; padding: 5px 14px; font-size: .8rem; letter-spacing: .03em; }
table.legend td { padding: 5px 14px; border-top: 1px solid var(--line); }
table.legend td.sym { font: italic 600 1.05rem Georgia, "Times New Roman", serif; color: var(--c); text-align: center; }
table.legend td.unit { font-weight: 700; white-space: nowrap; }

/* Brüche */
.frac { display: inline-flex; flex-direction: column; vertical-align: middle; text-align: center; margin: 0 .2em; line-height: 1.2; font-size: .95em; }
.frac > span:first-child { border-bottom: 1.5px solid currentColor; padding: 0 .25em .05em; }
.frac > span:last-child { padding: .05em .25em 0; }
sup .frac, sub .frac { font-size: .85em; }

/* Simulationen */
.simbox { margin-top: 18px; background: var(--card); border: 2px solid var(--c); border-radius: 18px; overflow: hidden; }
.simhead { background: var(--t); color: var(--c); padding: 8px 18px; font-weight: 700; border-bottom: 2px solid var(--c); }
.simhint { margin: 10px 18px 0; color: #4a4368; font-size: .95rem; }
.simroot { padding: 10px 14px 16px; }
.simcanvas { width: 100%; height: auto; display: block; border-radius: 12px; border: 1px solid var(--line); }
.simout { margin: 10px 0 0; padding: 8px 12px; background: #f3f0fa; border-radius: 10px; font-size: .95rem; }
.simout.big { font-size: 1.15rem; padding: 14px 16px; }
.simout .warn { color: var(--bad); }
.muted { color: var(--muted); }
.simctrls { display: flex; flex-wrap: wrap; gap: 10px 22px; align-items: end; margin-top: 12px; }
.ctrl { display: flex; flex-direction: column; font-size: .85rem; color: #4a4368; min-width: 170px; }
.ctrl .cv { font-weight: 700; color: var(--ink); font-size: .95rem; }
.ctrl input[type=range] { accent-color: var(--c); width: 100%; }
.ctrl select, .ctrl input[type=text] { font: inherit; padding: 6px 8px; border-radius: 8px; border: 1px solid #cfc7e6; background: #fff; }

.btn { font: inherit; font-size: .95rem; cursor: pointer; border: 0; border-radius: 10px; padding: 8px 16px; background: var(--c); color: #fff; display: inline-block; }
.btn:hover { filter: brightness(1.08); }
.btn.ghost { background: #fff; color: var(--c); border: 2px solid var(--c); font-weight: 600; }
.btn.ghost:hover { background: var(--c); color: #fff; filter: none; }

/* Übungen */
.quiz { margin-top: 30px; }
.qhead { display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; gap: 10px; }
.quiz h2 { font-size: 1.3rem; margin: 0; }
.qcard { background: var(--card); border-radius: var(--r); padding: 16px 20px; margin: 12px 0; box-shadow: 0 1px 3px rgba(80,60,140,.08); }
.qn { font-size: .78rem; text-transform: uppercase; letter-spacing: .06em; color: var(--c); font-weight: 700; }
.qt { margin: 2px 0 10px; font-weight: 500; }
.opts { display: grid; gap: 8px; }
.opt { font: inherit; text-align: left; cursor: pointer; padding: 10px 14px; border-radius: 10px; border: 2px solid var(--line); background: #fff; color: var(--ink); }
.opt:hover:not(:disabled) { border-color: var(--c); background: var(--t); }
.opt.ok { border-color: var(--ok); background: var(--mint); }
.opt.bad { border-color: var(--bad); background: #fbe0e6; }
.numrow { display: flex; gap: 10px; align-items: center; flex-wrap: wrap; }
.numrow input { font: inherit; width: 140px; padding: 8px 10px; border-radius: 10px; border: 2px solid var(--line); }
.numrow input.ok { border-color: var(--ok); background: var(--mint); }
.numrow input.bad { border-color: var(--bad); background: #fbe0e6; }
.fb { margin-top: 8px; font-size: .95rem; }
.fb.ok { color: #1e6b41; } .fb.bad { color: #a23049; }
.score { margin-top: 14px; padding: 14px 18px; background: var(--t); border: 2px solid var(--c); border-radius: 14px; display: flex; gap: 14px; align-items: center; flex-wrap: wrap; }
.pager { display: flex; justify-content: space-between; gap: 12px; margin-top: 26px; flex-wrap: wrap; }
.pager a { background: var(--card); border: 2px solid var(--c); color: var(--c); padding: 8px 16px; border-radius: 12px; font-weight: 600; }
.pager a:hover { background: var(--c); color: #fff; }

/* Aufgabenblatt */
.toolbar { display: flex; flex-wrap: wrap; align-items: center; gap: 14px 22px; background: var(--card); border: 2px solid var(--c); border-radius: 14px; padding: 12px 18px; margin-bottom: 16px; }
.toolbar a { color: var(--c); font-weight: 600; }
.toolbar p { margin: 0; font-size: .85rem; flex-basis: 100%; }
.sheet { background: #fff; border-radius: 12px; padding: 28px 34px; box-shadow: 0 1px 6px rgba(80,60,140,.1); }
.sh-head { display: flex; justify-content: space-between; color: var(--c); border-bottom: 3px solid var(--c); padding-bottom: 6px; }
.sheet h1 { font-size: 1.6rem; margin: 14px 0 8px; }
.sh-meta { display: flex; flex-wrap: wrap; gap: 8px 30px; margin-bottom: 8px; }
.sh-topic h2 { font-size: 1.2rem; color: var(--c); margin: 20px 0 6px; }
.sh-task { break-inside: avoid; margin: 10px 0 14px; }
.sh-task p { margin: .3em 0; }
.sh-opts { list-style: none; padding-left: 18px; margin: 4px 0; }
.sh-line span { display: inline-block; min-width: 200px; border-bottom: 1px solid #333; }
.sh-line.calc span { min-width: 380px; margin-bottom: 6px; }
.solutions { margin-top: 30px; padding-top: 10px; border-top: 2px dashed var(--c); }
.solutions h2 { color: var(--c); }
.solutions h3 { margin: 12px 0 2px; }
.solutions ol { margin: 4px 0; font-size: .95rem; }
.sheet.nosol .solutions { display: none; }

@media (max-width: 600px) {
  body { font-size: 16px; }
  .block { padding: 4px 16px 10px; }
  .ctrl { min-width: 100%; }
  .sheet { padding: 18px; }
}

@media print {
  @page { margin: 16mm; }
  body { background: #fff; font-size: 11.5pt; color: #000; }
  .top, footer, .noprint, .crumbs { display: none !important; }
  main { padding: 0; max-width: none; }
  .sheet { box-shadow: none; padding: 0; border-radius: 0; }
  .solutions { break-before: page; border-top: 0; }
  .sh-topic h2 { break-after: avoid; }
}