:root { font-family: Arial, sans-serif; color: #273342; background: #f6f8fb; --accent: #41698e; --muted: #596778; --line: #dce5ee; --soft: #e6eef7; }
* { 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: #dce9f5; color: var(--accent); font-size: 1.5rem; }
.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, button:focus-visible, input:focus-visible { outline: 3px solid #bb774c; outline-offset: 3px; }
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: var(--soft); }
.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: 650px; margin: 0; color: #4d6175; 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: #273342; font-size: 1.7rem; }
.topic-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 20px; }
.topic-card { display: flex; gap: 22px; min-height: 225px; padding: 27px; border: 1px solid var(--line); border-radius: 22px; background: white; color: inherit; text-decoration: none; box-shadow: 0 9px 23px #243c560b; transition: transform .2s, box-shadow .2s; }
.topic-card:hover { transform: translateY(-4px); box-shadow: 0 15px 29px #243c561c; }
.icon-tile { display: grid; place-items: center; flex: 0 0 90px; width: 90px; height: 90px; border-radius: 19px; background: #edf3fa; }
.icon-tile img { width: 75px; height: 75px; object-fit: contain; }
.sinus-icon { color: var(--accent); font-size: 3.5rem; line-height: 1; }
.card-copy { display: flex; flex-direction: column; align-items: flex-start; gap: 9px; color: var(--muted); line-height: 1.55; }
.card-copy strong { color: #273342; font-size: 1.5rem; line-height: 1.2; }
.card-copy .kicker { margin: 0; }
.card-link { margin-top: auto; padding-top: 13px; color: var(--accent); font-weight: 800; }
footer { padding-bottom: 30px; color: #7a8794; font-size: .87rem; }
.article-main { max-width: 870px; padding: 12px 0 90px; }
.back-link { display: inline-block; margin-bottom: 27px; }
.article-hero { padding: 40px; border-radius: 26px; background: var(--soft); }
.article-hero h1 { margin-bottom: 12px; font-size: clamp(2.2rem, 5vw, 3.3rem); line-height: 1.12; }
.article-hero p:last-child { max-width: 680px; margin-bottom: 0; color: #4d6175; line-height: 1.65; }
.article-main article > p, .article-section p { color: #485765; font-size: 1.04rem; line-height: 1.72; }
.intro { margin: 33px 0 24px; }
.article-section { margin-top: 34px; }
.article-section h2 { margin-bottom: 11px; font-size: 1.55rem; }
.sketch { margin: 20px 0 26px; padding: 14px; border: 1px solid var(--line); border-radius: 18px; background: white; }
.sketch img { display: block; width: 100%; height: auto; }
.sketch figcaption { padding: 9px 9px 2px; color: var(--muted); font-size: .92rem; line-height: 1.55; }
.formula { margin: 16px 0; padding: 16px 20px; border-radius: 13px; background: #edf3fa; font-size: 1.18rem; font-weight: 700; line-height: 1.55; }
.formula small { display: block; margin-top: 7px; color: var(--muted); font-size: .82rem; font-weight: 400; }
.key-point { margin-top: 28px; padding: 20px 24px; border-left: 4px solid #779bbb; border-radius: 0 14px 14px 0; background: #edf3fa; line-height: 1.65; }
.key-point p { margin: 0; }
.next { margin-top: 36px; padding-top: 22px; border-top: 1px solid var(--line); }
@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; } .article-hero { padding: 27px; } .topic-card { gap: 15px; padding: 20px; } .icon-tile { flex-basis: 65px; width: 65px; height: 65px; } .icon-tile img { width: 55px; height: 55px; } .sketch { padding: 6px; } }

/* Interaktive Aufgabe */
.osc-card { -webkit-perspective: 1200px; perspective: 1200px; }
.osc-inner { display: grid; -webkit-transform-style: preserve-3d; transform-style: preserve-3d; transition: transform .7s ease; }
.osc-card.is-flipped .osc-inner { -webkit-transform: rotateY(180deg); transform: rotateY(180deg); }
.osc-face { grid-area: 1 / 1; min-width: 0; padding: clamp(12px, 3vw, 23px); border: 1px solid var(--line); border-radius: 19px; background: white; -webkit-backface-visibility: hidden; backface-visibility: hidden; box-shadow: 0 9px 22px #243c560b; transition: visibility 0s linear .35s; }
.osc-front { visibility: visible; }
.osc-card.is-flipped .osc-front { visibility: hidden; }
.osc-back { visibility: hidden; -webkit-transform: rotateY(180deg); transform: rotateY(180deg); }
.osc-card.is-flipped .osc-back { visibility: visible; }
.osc-face h2 { margin-bottom: 13px; font-size: 1.4rem; }
.osc-plot-frame { border: 1px solid var(--line); border-radius: 9px; overflow: hidden; }
.osc-plot { display: block; width: 100%; height: auto; font-family: Arial, sans-serif; }
.osc-interactive { cursor: crosshair; touch-action: none; }
.osc-grid { stroke: #e9e7e2; stroke-width: 1; }
.osc-axis { fill: none; stroke: #272727; stroke-width: 3.2; stroke-linecap: round; stroke-linejoin: round; }
.osc-tick { stroke: #272727; stroke-width: 2; }
.osc-tick-label { fill: #272727; font-size: 18px; }
.osc-axis-label { fill: #272727; font-size: 21px; font-weight: 700; }
.osc-curve { fill: none; stroke: #252525; stroke-width: 3.1; stroke-linecap: round; }
.osc-answer { fill: none; stroke: #b45e35; stroke-width: 3.6; stroke-linecap: round; stroke-linejoin: round; }
.osc-own { fill: none; stroke: #276f90; stroke-width: 3.5; stroke-linecap: round; stroke-linejoin: round; }
.osc-marker { fill: white; stroke: #276f90; stroke-width: 3; }
.osc-own-label { fill: #276f90; font-size: 22px; font-weight: 700; }
.osc-answer-label { fill: #b45e35; font-size: 22px; font-weight: 700; }
.osc-legend { display: flex; flex-wrap: wrap; align-items: center; gap: 8px; margin: 12px 0 0; color: var(--muted); font-size: .9rem; }
.osc-key { display: inline-block; width: 18px; height: 10px; margin-left: 8px; border-top: 4px solid; }
.osc-key:first-child { margin-left: 0; }
.osc-key--own { color: #276f90; }
.osc-key--answer { color: #b45e35; }
.osc-controls, .mark-tools { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 15px; }
.osc-controls button, .mark-tools button { padding: 11px 15px; border: 1px solid var(--accent); border-radius: 10px; background: var(--accent); color: white; font: inherit; font-weight: 700; cursor: pointer; }
.osc-controls button.secondary, .mark-tools button { background: white; color: var(--accent); }
.mark-tools button[aria-pressed="true"] { background: var(--accent); color: white; }
.osc-controls button:disabled { opacity: .48; cursor: not-allowed; }
.osc-controls button[hidden], .mark-tools[hidden] { display: none; }
.osc-input { display: flex; flex-wrap: wrap; align-items: end; gap: 17px 24px; margin-top: 20px; }
.osc-field label { display: block; margin-bottom: 7px; font-weight: 700; }
.osc-field > div { display: flex; align-items: center; gap: 8px; }
.osc-input input { width: 125px; padding: 10px 12px; border: 1px solid #b7cad9; border-radius: 9px; color: inherit; font: inherit; }
.osc-input p { flex-basis: 100%; margin: 0; color: var(--muted); font-size: .93rem; }
.osc-input[hidden] { display: none; }
.osc-evaluation { margin-top: 16px; padding: 16px 18px; border-radius: 12px; background: #edf3fa; line-height: 1.6; }
.osc-evaluation p { margin-bottom: 7px; }
.osc-evaluation p:last-child { margin-bottom: 0; }
.osc-status { margin-top: 12px; color: var(--muted); line-height: 1.5; }
@media (prefers-reduced-motion: reduce) { .osc-inner, .osc-face { transition: none; } }

/* Selbstlerneinheit mit zwei Lernwegen */
.learning-intro .formula, .learning-path .formula { overflow-x: auto; }
.path-choice { margin: 42px 0 34px; }
.path-choice h2 { margin-bottom: 18px; font-size: 1.65rem; }
.path-choice-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 16px; }
.path-choice-button { display: flex; flex-direction: column; align-items: flex-start; gap: 10px; width: 100%; min-height: 132px; padding: 21px; border: 1px solid var(--line); border-radius: 17px; background: white; color: #273342; text-align: left; font: inherit; line-height: 1.5; cursor: pointer; box-shadow: 0 7px 18px #243c560a; }
.path-choice-button strong { font-size: 1.23rem; }
.path-choice-button span { color: var(--muted); }
.path-choice-button[aria-pressed="true"] { border: 2px solid var(--accent); background: #f1f6fb; padding: 20px; }
.learning-path { scroll-margin-top: 24px; }
.learning-path[hidden], .learning-step[hidden], .learning-answer[hidden], .path-summary[hidden] { display: none; }
.path-header { margin: 20px 0 22px; padding: 24px 26px; border-radius: 18px; background: var(--soft); }
.path-header .eyebrow { margin-bottom: 9px; }
.path-header h2 { margin: 0 0 9px; font-size: 1.75rem; }
.path-header p:last-child { margin: 0; line-height: 1.65; color: #4d6175; }
.learning-step { position: relative; margin: 20px 0; padding: 24px 25px; border: 1px solid var(--line); border-radius: 18px; background: white; box-shadow: 0 7px 18px #243c5609; }
.learning-step h3 { margin: 0 0 12px; padding-left: 42px; font-size: 1.35rem; }
.learning-step p { color: #485765; line-height: 1.7; }
.step-number { position: absolute; top: 20px; left: 24px; display: grid; place-items: center; width: 30px; height: 30px; border-radius: 9px; background: var(--soft); color: var(--accent); font-weight: 800; }
.learning-step .sketch { margin: 20px 0; }
.measurement-notes { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 13px 18px; margin: 20px 0 23px; padding: 17px; border: 1px solid var(--line); border-radius: 13px; background: #f8fbfe; }
.measurement-notes label { display: flex; flex-direction: column; gap: 7px; color: #364b5d; font-weight: 700; }
.measurement-notes input { width: 100%; padding: 10px 11px; border: 1px solid #b8cadb; border-radius: 9px; background: white; color: inherit; font: inherit; }
.reveal-answer { display: flex; justify-content: space-between; align-items: center; gap: 18px; width: 100%; margin-top: 19px; padding: 15px 17px; border: 1px solid #b8cadb; border-radius: 12px; background: #f1f6fb; color: #273342; text-align: left; font: inherit; font-weight: 700; line-height: 1.5; cursor: pointer; }
.reveal-answer:hover { background: #e6eef7; }
.reveal-answer > span { flex: 0 0 auto; color: var(--accent); font-size: .89rem; }
.reveal-answer[aria-expanded="true"] { border-radius: 12px 12px 0 0; }
.learning-answer { padding: 17px 19px; border: 1px solid #b8cadb; border-top: 0; border-radius: 0 0 12px 12px; background: #f8fbfe; color: #364b5d; line-height: 1.65; }
.path-summary { margin: 26px 0 38px; padding: 25px 27px; border-left: 4px solid var(--accent); border-radius: 0 16px 16px 0; background: var(--soft); }
.path-summary h3 { margin-bottom: 10px; font-size: 1.45rem; }
.path-summary p { line-height: 1.75; }
.switch-path { padding: 11px 15px; border: 1px solid var(--accent); border-radius: 10px; background: var(--accent); color: white; font: inherit; font-weight: 700; cursor: pointer; }
@media (max-width: 680px) { .path-choice-grid, .measurement-notes { grid-template-columns: 1fr; } .learning-step { padding: 20px; } .reveal-answer { flex-direction: column; align-items: flex-start; gap: 4px; } }

/* Gemessene Pendelkurven anpassen */
.data-details { margin: 32px 0; border: 1px solid var(--line); border-radius: 16px; background: white; }
.data-details summary { padding: 17px 21px; color: var(--accent); font-weight: 800; cursor: pointer; }
.data-details p { margin: 0; padding: 0 21px 15px; color: var(--muted); line-height: 1.5; }
.data-scroll { max-height: 370px; overflow: auto; border-top: 1px solid var(--line); }
.data-scroll table { width: 100%; min-width: 690px; border-collapse: collapse; font-variant-numeric: tabular-nums; }
.data-scroll th, .data-scroll td { padding: 9px 12px; border-bottom: 1px solid var(--line); text-align: right; white-space: nowrap; }
.data-scroll th { position: sticky; top: 0; background: var(--soft); font-size: .85rem; }
.data-scroll tbody tr:nth-child(even) { background: #f8fbfe; }
.curve-panel { margin: 28px 0; padding: 25px; border: 1px solid var(--line); border-radius: 18px; background: white; box-shadow: 0 8px 21px #243c560b; }
.curve-panel h2 { margin-bottom: 10px; }
.curve-panel > p { color: #485765; line-height: 1.65; }
.curve-formula { margin: 17px 0 21px; padding: 13px 17px; overflow-x: auto; border-radius: 11px; background: var(--soft); font-size: 1.13rem; }
.fit-controls { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 18px 22px; margin-bottom: 24px; }
.fit-controls label { display: grid; grid-template-columns: 1fr auto; gap: 8px; align-items: center; font-weight: 700; }
.fit-controls input { grid-column: 1 / -1; width: 100%; accent-color: var(--accent); }
.fit-controls output { color: var(--accent); font-variant-numeric: tabular-nums; }
.curve-frame { border: 1px solid var(--line); border-radius: 10px; overflow: hidden; }
.curve-frame svg { display: block; width: 100%; height: auto; font-family: Arial, sans-serif; }
.fit-grid { stroke: #e8e8e8; stroke-width: 1; }
.fit-tick { stroke: #282828; stroke-width: 2; }
.fit-axis { fill: none; stroke: #282828; stroke-width: 3.2; stroke-linecap: round; stroke-linejoin: round; }
.fit-axis-label { fill: #282828; font-size: 18px; font-weight: 700; }
.fit-tick-label { fill: #282828; font-size: 15px; }
.fit-measurement { fill: #202020; }
.fit-model { fill: none; stroke: #a9502f; stroke-width: 3.2; stroke-linecap: round; stroke-linejoin: round; }
.curve-legend { display: flex; align-items: center; gap: 8px 13px; flex-wrap: wrap; margin: 12px 0 0; font-size: .9rem; }
.data-dot { width: 9px; height: 9px; border-radius: 50%; background: #202020; }
.model-stroke { width: 23px; border-top: 3px solid #a9502f; }
@media (max-width: 600px) { .curve-panel { padding: 14px; } .fit-controls { grid-template-columns: 1fr; } }
.comparison-answer { margin-top: 18px; border: 1px solid var(--line); border-radius: 12px; overflow: hidden; }
.comparison-answer summary { padding: 15px 18px; color: var(--accent); background: var(--soft); font-weight: 800; cursor: pointer; }
.comparison-answer .data-scroll { max-height: none; }
.comparison-answer table { min-width: 620px; }
.comparison-answer th, .comparison-answer td { text-align: left; white-space: normal; vertical-align: top; line-height: 1.5; }
.comparison-answer > p { margin: 0; padding: 17px 19px; line-height: 1.65; }