:root { font-family: Arial, sans-serif; color: #2d2c2a; background: #fbf8f3; --accent: #965633; --muted: #615e58; --line: #e9ded2; }
* { box-sizing: border-box; }
body { margin: 0; }
.site-header, .home-main, .article-main, footer { width: min(1120px, calc(100% - 40px)); margin-inline: auto; }
.site-header { display: flex; align-items: center; justify-content: space-between; gap: 20px; padding: 28px 0; }
.brand { display: inline-flex; align-items: center; gap: 10px; color: inherit; text-decoration: none; font-size: 1.12rem; font-weight: 800; }
.brand-mark { display: grid; place-items: center; width: 35px; height: 35px; border-radius: 11px; background: #f7e6d7; color: var(--accent); font-size: 1.45rem; }
.all-projects, .back-link, .next-link { color: var(--accent); font-weight: 700; text-decoration: none; }
.all-projects:hover, .back-link:hover, .next-link:hover { text-decoration: underline; }
.brand:focus-visible, .all-projects:focus-visible, .back-link:focus-visible, .next-link:focus-visible, .topic-card:focus-visible { outline: 3px solid #b26a43; outline-offset: 4px; }
h1, h2, h3, p { margin-top: 0; }
h1, h2, h3, .topic-card strong { letter-spacing: -.03em; }
.hero { margin-top: 22px; padding: clamp(38px, 7vw, 76px); border-radius: 28px; background: #f7e6d7; }
.eyebrow, .kicker { margin: 0 0 15px; color: var(--accent); font-size: .77rem; font-weight: 800; letter-spacing: .1em; text-transform: uppercase; }
.hero h1 { max-width: 770px; margin-bottom: 18px; font-size: clamp(2.35rem, 5vw, 4.15rem); line-height: 1.1; }
.hero p:last-child { max-width: 640px; margin: 0; color: #655344; font-size: 1.1rem; line-height: 1.65; }
.topics { padding: 55px 0 90px; }
.section-heading { display: flex; justify-content: space-between; align-items: baseline; gap: 18px; margin-bottom: 22px; color: var(--muted); }
.section-heading h2 { margin: 0; color: #2d2c2a; font-size: 1.7rem; }
.topic-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 18px; }
.topic-card { display: flex; gap: 20px; min-height: 214px; padding: 27px; border: 1px solid var(--line); border-radius: 22px; background: white; color: inherit; text-decoration: none; box-shadow: 0 9px 22px #4c2c1809; transition: transform .2s, box-shadow .2s; }
.topic-card:hover { transform: translateY(-4px); box-shadow: 0 15px 28px #4c2c181a; }
.topic-number { display: grid; place-items: center; flex: 0 0 65px; width: 65px; height: 65px; border-radius: 18px; background: #f9eee5; color: var(--accent); font-size: 1.18rem; font-weight: 800; }
.topic-copy { display: flex; flex-direction: column; align-items: flex-start; gap: 8px; color: var(--muted); line-height: 1.5; }
.topic-copy .kicker { margin: 0; }
.topic-copy strong { color: #2d2c2a; font-size: 1.45rem; line-height: 1.22; }
.card-link { margin-top: auto; padding-top: 14px; color: var(--accent); font-weight: 800; }
footer { padding-bottom: 30px; color: #8a8178; font-size: .86rem; }
.article-main { max-width: 850px; padding: 12px 0 90px; }
.back-link { display: inline-block; margin-bottom: 27px; }
.article-hero { padding: 39px; border-radius: 26px; background: #f7e6d7; }
.article-hero h1 { margin-bottom: 12px; font-size: clamp(2.2rem, 5vw, 3.25rem); line-height: 1.12; }
.article-hero p:last-child { max-width: 650px; margin-bottom: 0; color: #655344; line-height: 1.65; }
.article-main article > p, .article-main article > section > p { color: #4f4c47; font-size: 1.04rem; line-height: 1.72; }
.intro { margin: 34px 0 24px; }
.sketch { margin: 27px 0 34px; padding: 12px; border: 1px solid var(--line); border-radius: 18px; background: white; }
.sketch img { display: block; width: 100%; height: auto; border-radius: 8px; }
.sketch figcaption { padding: 9px 10px 3px; color: var(--muted); font-size: .92rem; line-height: 1.55; }
.article-section { margin-top: 30px; }
.article-section h2 { margin-bottom: 11px; font-size: 1.5rem; }
.key-point { margin: 28px 0; padding: 22px 25px; border-left: 4px solid #c08158; border-radius: 0 14px 14px 0; background: #f9eee5; line-height: 1.65; }
.key-point p { margin: 0; }
.question { margin: 30px 0 0; padding: 22px 25px; border: 1px solid var(--line); border-radius: 16px; background: white; line-height: 1.6; }
.question p { margin: 0; }
.next { margin-top: 35px; padding-top: 22px; border-top: 1px solid var(--line); }
.source-note { margin-top: 28px; color: var(--muted); font-size: .86rem; line-height: 1.5; }
.source-note a { color: var(--accent); }
@media (max-width: 760px) { .topic-grid { grid-template-columns: 1fr; } }
@media (max-width: 480px) { .site-header, .home-main, .article-main, footer { width: calc(100% - 28px); } .all-projects { font-size: .85rem; } .hero, .article-hero { padding: 28px; } .topic-card { gap: 15px; padding: 20px; } .topic-number { flex-basis: 50px; width: 50px; height: 50px; } .sketch { padding: 5px; } }

/* Diagrammübung */
.measurement-wrap { overflow-x: auto; }
.measurement { width: min(440px, 100%); border-collapse: collapse; background: white; }
.measurement caption { margin-bottom: 9px; text-align: left; font-weight: 700; }
.measurement th, .measurement td { padding: 10px 16px; border: 1px solid var(--line); text-align: left; }
.measurement th { background: #f9eee5; }
.plot-exercise { margin-top: 42px; }
.plot-exercise > p { line-height: 1.65; }
.flip-card { -webkit-perspective: 1200px; perspective: 1200px; }
.flip-card-inner { display: grid; -webkit-transform-style: preserve-3d; transform-style: preserve-3d; transition: transform .7s ease; }
.flip-card.is-flipped .flip-card-inner { -webkit-transform: rotateY(180deg); transform: rotateY(180deg); }
/* Visibility keeps Safari from painting both stacked SVG faces at once. */
.flip-face { grid-area: 1 / 1; min-width: 0; padding: clamp(12px, 3vw, 24px); border: 1px solid var(--line); border-radius: 19px; background: white; -webkit-backface-visibility: hidden; backface-visibility: hidden; box-shadow: 0 9px 22px #4c2c1809; transition: visibility 0s linear .35s; }
.flip-front { visibility: visible; }
.flip-card.is-flipped .flip-front { visibility: hidden; }
.flip-face h3 { margin-bottom: 15px; }
.flip-back { visibility: hidden; -webkit-transform: rotateY(180deg); transform: rotateY(180deg); }
.flip-card.is-flipped .flip-back { visibility: visible; }
.flip-back > p:last-child { margin-bottom: 0; line-height: 1.55; }
.plot-frame { width: 100%; border: 1px solid #eee7df; border-radius: 10px; overflow: hidden; }
.plot { display: block; width: 100%; height: auto; font-family: Arial, sans-serif; }
.interactive-plot { cursor: crosshair; touch-action: none; }
.plot .grid-line { stroke: #e7e2dc; stroke-width: 1; }
.plot .tick { stroke: #332f2b; stroke-width: 2; }
.plot .axis { fill: none; stroke: #332f2b; stroke-width: 3.3; stroke-linecap: round; stroke-linejoin: round; }
.plot .tick-label { fill: #332f2b; font-size: 18px; }
.plot .axis-label { fill: #332f2b; font-size: 22px; font-weight: 700; }
.plot .own-dot { fill: #266e8b; stroke: white; stroke-width: 2; }
.plot .answer-ring { fill: none; stroke: #965633; stroke-width: 4; }
.plot-legend { display: flex; align-items: center; gap: 7px; margin: 12px 0 0; font-size: .9rem; color: var(--muted); }
.legend-dot { display: inline-block; width: 13px; height: 13px; border-radius: 50%; }
.legend-dot--own { background: #266e8b; }
.legend-dot--solution { border: 3px solid #965633; }
.exercise-controls { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 16px; }
.exercise-controls button { padding: 12px 16px; border: 1px solid var(--accent); border-radius: 10px; background: var(--accent); color: white; font: inherit; font-weight: 700; cursor: pointer; }
.exercise-controls button#clear-button { background: white; color: var(--accent); }
.exercise-controls button:disabled { opacity: .48; cursor: not-allowed; }
.exercise-controls button:focus-visible { outline: 3px solid #b26a43; outline-offset: 3px; }
.exercise-controls button[hidden] { display: none; }
.exercise-status { margin-top: 12px; color: var(--muted); }
@media (prefers-reduced-motion: reduce) { .flip-card-inner, .flip-face { transition: none; } }

/* Zusatzübung: fünf Punkte ohne Einheiten */
.practice-only { margin-top: 34px; }
.practice-only h2 { margin-bottom: 14px; font-size: 1.5rem; }
.point-list { margin-bottom: 22px; padding: 15px 18px; border-radius: 13px; background: #f9eee5; font-size: 1.22rem; font-weight: 700; letter-spacing: .02em; line-height: 1.9; word-spacing: .3em; }
.evaluation { margin-top: 17px; padding: 15px 18px; border-radius: 12px; background: #f9eee5; line-height: 1.55; }
.evaluation h4 { margin: 0 0 4px; font-size: 1.25rem; }
.evaluation p { margin: 0 0 6px; }
.evaluation p:last-child { margin-bottom: 0; }
.exercise-controls button#new-button { background: white; color: var(--accent); }

/* Übung zur gleichförmigen Bewegung */
.motion-sketch { margin-bottom: 25px; }
.motion-practice { margin-top: 28px; }
.motion-situation { padding: 24px 26px; border-radius: 18px; background: #f9eee5; }
.motion-situation h2 { margin-bottom: 9px; font-size: 1.55rem; }
.motion-situation > p:not(.eyebrow) { margin-bottom: 17px; color: #4f4c47; font-size: 1.05rem; line-height: 1.65; }
.formula-strip { display: flex; flex-wrap: wrap; gap: 10px; }
.formula-strip strong { padding: 9px 13px; border: 1px solid #dfc7b6; border-radius: 10px; background: white; }
.calculation-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 15px; margin: 22px 0 38px; }
.calculation-card { position: relative; display: flex; flex-direction: column; gap: 13px; min-height: 220px; padding: 22px; border: 1px solid var(--line); border-radius: 17px; background: white; box-shadow: 0 7px 18px #4c2c1809; }
.calculation-card > strong { padding-right: 36px; line-height: 1.5; }
.task-symbol { position: absolute; top: 16px; right: 17px; display: grid; place-items: center; width: 34px; height: 34px; border-radius: 50%; background: #f9eee5; color: var(--accent); font-size: 1.15rem; font-weight: 800; }
.answer-entry { display: flex; align-items: center; gap: 7px; margin-top: auto; font-weight: 700; }
.answer-entry input { width: 105px; padding: 10px 12px; border: 1px solid #bea894; border-radius: 9px; color: inherit; font: inherit; }
.answer-feedback { min-height: 2.8em; color: var(--muted); font-size: .9rem; line-height: 1.45; }
.answer-feedback.is-correct { color: #33704a; font-weight: 700; }
.answer-feedback.is-correction { color: #8a492b; font-weight: 700; }
.motion-graph-task { margin-top: 30px; }
.motion-graph-task > p { color: #4f4c47; line-height: 1.65; }
.motion-points { padding: 14px 17px; border-radius: 12px; background: #f9eee5; font-size: 1.04rem; font-weight: 700; line-height: 1.8; word-spacing: .15em; }
.motion-plot-frame { border: 1px solid #eee7df; border-radius: 11px; overflow: hidden; background: white; }
.motion-plot { display: block; width: 100%; height: auto; font-family: Arial, sans-serif; }
.motion-plot--interactive { cursor: crosshair; touch-action: none; }
.motion-grid { stroke: #e7e2dc; stroke-width: 1; }
.motion-tick { stroke: #302e2b; stroke-width: 2; }
.motion-axis { fill: none; stroke: #302e2b; stroke-width: 3.5; stroke-linecap: round; stroke-linejoin: round; }
.motion-tick-label { fill: #302e2b; font-size: 18px; }
.motion-axis-label { fill: #302e2b; font-size: 21px; font-weight: 700; }
.motion-own-dot { fill: #266e8b; stroke: white; stroke-width: 2; }
.motion-answer-ring { fill: none; stroke: #965633; stroke-width: 4; }
.motion-answer-line { fill: none; stroke: #965633; stroke-width: 3.5; stroke-linecap: round; }
.motion-actions { display: flex; flex-wrap: wrap; gap: 11px; margin-top: 28px; }
.motion-actions button { padding: 13px 18px; border: 1px solid var(--accent); border-radius: 10px; background: var(--accent); color: white; font: inherit; font-weight: 700; cursor: pointer; }
.motion-actions #new-motion { background: white; color: var(--accent); }
.motion-solution { margin-top: 25px; padding: 23px 26px; border-left: 4px solid #c08158; border-radius: 0 15px 15px 0; background: #f9eee5; }
.motion-solution[hidden] { display: none; }
.motion-solution h2 { margin-bottom: 13px; }
.motion-solution p { margin-bottom: 10px; line-height: 1.65; }
.motion-solution p:last-child { margin-bottom: 0; }
@media (max-width: 720px) { .calculation-grid { grid-template-columns: 1fr; } .calculation-card { min-height: 0; } }