diff --git a/public/auth_helpers.php b/public/auth_helpers.php
index 99ed07b..df96522 100644
--- a/public/auth_helpers.php
+++ b/public/auth_helpers.php
@@ -135,5 +135,6 @@ function manageablePublicPages(): array
         'wochenvorhersage.php' => 'Wochenvorhersage',
         'satellitenhimmel.php' => 'Satellitenhimmel',
         'asteroid_temp.php' => 'Asteroid-Temperatur',
+        'universesandbox.php' => 'Universe Sandbox',
     ];
 }
diff --git a/public/header.php b/public/header.php
index 6d7d4e8..a413308 100644
--- a/public/header.php
+++ b/public/header.php
@@ -157,6 +157,7 @@ $menuGroups = [
             ['href' => 'geocron/index.php',         'label' => 'Geocron'],
             ['href' => 'geocron3d.php',             'label' => 'Geocron 3D'],
             ['href' => 'geocron3d_C.php',           'label' => 'Geocron 3D Cesium'],
+            ['href' => 'universesandbox.php',       'label' => 'Universe Sandbox'],
         ],
     ],
     [
diff --git a/public/universesandbox.php b/public/universesandbox.php
new file mode 100644
index 0000000..f5d675b
--- /dev/null
+++ b/public/universesandbox.php
@@ -0,0 +1,824 @@
+<?php
+declare(strict_types=1);
+
+session_start();
+
+$pageTitle      = 'Universe Sandbox – AstroTools';
+$bodyClass      = 'usb-page';
+$publicBasePath = './';
+
+require __DIR__ . '/header.php';
+?>
+
+<style>
+/* ── Layout ───────────────────────────────────────────── */
+.usb-wrap {
+    display: flex;
+    flex-direction: column;
+    gap: 0;
+    height: calc(100vh - 120px);
+    min-height: 500px;
+}
+
+/* ── Toolbar ──────────────────────────────────────────── */
+.usb-toolbar {
+    display: flex;
+    flex-wrap: wrap;
+    align-items: center;
+    gap: .5rem;
+    padding: .6rem .75rem;
+    background: var(--bg-card);
+    border: 1px solid var(--border);
+    border-radius: var(--radius) var(--radius) 0 0;
+    flex-shrink: 0;
+}
+
+.usb-toolbar-group {
+    display: flex;
+    align-items: center;
+    gap: .35rem;
+}
+
+.usb-sep {
+    width: 1px;
+    height: 24px;
+    background: var(--border);
+    flex-shrink: 0;
+}
+
+.usb-label {
+    color: var(--text-dim);
+    font-size: .75rem;
+    text-transform: uppercase;
+    letter-spacing: .05em;
+    white-space: nowrap;
+}
+
+.usb-mode-btn {
+    padding: .3rem .7rem;
+    border-radius: var(--radius);
+    font-size: .8rem;
+    cursor: pointer;
+    border: 1px solid var(--border);
+    background: transparent;
+    color: var(--text-dim);
+    transition: background .15s, color .15s, border-color .15s;
+    white-space: nowrap;
+}
+.usb-mode-btn:hover          { color: var(--gold); border-color: var(--gold-dim); }
+.usb-mode-btn.is-active      { background: var(--gold); color: #06080f; border-color: var(--gold); font-weight: 600; }
+.usb-mode-btn.is-danger      { border-color: #c0392b; color: #e74c3c; }
+.usb-mode-btn.is-danger:hover{ background: #c0392b; color: #fff; }
+
+.usb-slider-wrap {
+    display: flex;
+    align-items: center;
+    gap: .4rem;
+}
+.usb-slider {
+    -webkit-appearance: none;
+    width: 90px;
+    height: 4px;
+    border-radius: 2px;
+    background: var(--border);
+    outline: none;
+    cursor: pointer;
+}
+.usb-slider::-webkit-slider-thumb {
+    -webkit-appearance: none;
+    width: 14px; height: 14px;
+    border-radius: 50%;
+    background: var(--gold);
+    cursor: pointer;
+}
+.usb-value {
+    font-size: .78rem;
+    color: var(--gold-pale);
+    min-width: 38px;
+    text-align: right;
+}
+
+/* ── Canvas area ──────────────────────────────────────── */
+.usb-canvas-wrap {
+    position: relative;
+    flex: 1 1 0;
+    overflow: hidden;
+    background: #000;
+    border: 1px solid var(--border);
+    border-top: none;
+    border-radius: 0 0 var(--radius) var(--radius);
+    cursor: crosshair;
+}
+.usb-canvas-wrap.mode-orbit  { cursor: default; }
+.usb-canvas-wrap.mode-select { cursor: pointer; }
+
+#usbCanvas {
+    display: block;
+    width: 100%;
+    height: 100%;
+}
+
+/* ── HUD / overlay ────────────────────────────────────── */
+.usb-hud {
+    position: absolute;
+    bottom: .75rem;
+    left: .75rem;
+    font-size: .72rem;
+    color: var(--text-dim);
+    pointer-events: none;
+    line-height: 1.6;
+}
+
+.usb-hint {
+    position: absolute;
+    top: .75rem;
+    left: 50%;
+    transform: translateX(-50%);
+    background: rgba(6,8,15,.75);
+    border: 1px solid var(--border);
+    border-radius: var(--radius);
+    padding: .35rem .75rem;
+    font-size: .78rem;
+    color: var(--gold-pale);
+    pointer-events: none;
+    white-space: nowrap;
+    transition: opacity .4s;
+}
+
+/* ── Object panel ─────────────────────────────────────── */
+.usb-panel {
+    position: absolute;
+    top: .75rem;
+    right: .75rem;
+    width: 200px;
+    background: rgba(6,8,15,.88);
+    border: 1px solid var(--border);
+    border-radius: var(--radius);
+    padding: .65rem .75rem;
+    font-size: .78rem;
+    color: var(--text);
+    display: none;
+}
+.usb-panel.is-visible { display: block; }
+.usb-panel h3 {
+    font-size: .72rem;
+    text-transform: uppercase;
+    letter-spacing: .07em;
+    color: var(--gold);
+    margin: 0 0 .5rem;
+    border-bottom: 1px solid var(--border);
+    padding-bottom: .3rem;
+}
+.usb-panel-row {
+    display: flex;
+    justify-content: space-between;
+    margin-bottom: .25rem;
+}
+.usb-panel-key { color: var(--text-dim); }
+.usb-panel-val { color: var(--gold-pale); font-family: monospace; }
+
+/* ── Color picker swatches ─────────────────────────────── */
+.usb-swatches {
+    display: flex;
+    gap: .3rem;
+}
+.usb-swatch {
+    width: 18px; height: 18px;
+    border-radius: 50%;
+    cursor: pointer;
+    border: 2px solid transparent;
+    transition: border-color .15s, transform .15s;
+}
+.usb-swatch:hover  { transform: scale(1.2); }
+.usb-swatch.active { border-color: #fff; }
+
+/* ── Responsive ────────────────────────────────────────── */
+@media (max-width: 600px) {
+    .usb-wrap { height: calc(100vh - 100px); }
+    .usb-panel { display: none !important; }
+}
+</style>
+
+<!-- ══════════════════════════════════════════════════════
+     TOOLBAR
+═══════════════════════════════════════════════════════ -->
+<div class="usb-wrap">
+<div class="usb-toolbar">
+
+    <!-- Modus-Auswahl -->
+    <div class="usb-toolbar-group">
+        <span class="usb-label">Modus:</span>
+        <button class="usb-mode-btn is-active" id="usbModePlace">✦ Platzieren</button>
+        <button class="usb-mode-btn" id="usbModeOrbit">↻ Orbit</button>
+    </div>
+
+    <div class="usb-sep"></div>
+
+    <!-- Körper-Typ -->
+    <div class="usb-toolbar-group">
+        <span class="usb-label">Typ:</span>
+        <button class="usb-mode-btn is-active" id="typeStar"  data-type="star">★ Stern</button>
+        <button class="usb-mode-btn" id="typePlanet" data-type="planet">● Planet</button>
+        <button class="usb-mode-btn" id="typeMoon"   data-type="moon">○ Mond</button>
+    </div>
+
+    <div class="usb-sep"></div>
+
+    <!-- Farbe -->
+    <div class="usb-toolbar-group">
+        <span class="usb-label">Farbe:</span>
+        <div class="usb-swatches" id="usbSwatches">
+            <div class="usb-swatch active" style="background:#fffbe6" data-color="#fffbe6"></div>
+            <div class="usb-swatch" style="background:#ffd966" data-color="#ffd966"></div>
+            <div class="usb-swatch" style="background:#ff9944" data-color="#ff9944"></div>
+            <div class="usb-swatch" style="background:#ff4444" data-color="#ff4444"></div>
+            <div class="usb-swatch" style="background:#4fc3d8" data-color="#4fc3d8"></div>
+            <div class="usb-swatch" style="background:#88ff88" data-color="#88ff88"></div>
+            <div class="usb-swatch" style="background:#aaaaff" data-color="#aaaaff"></div>
+            <div class="usb-swatch" style="background:#bbbbbb" data-color="#bbbbbb"></div>
+        </div>
+    </div>
+
+    <div class="usb-sep"></div>
+
+    <!-- Masse -->
+    <div class="usb-toolbar-group">
+        <span class="usb-label">Masse:</span>
+        <div class="usb-slider-wrap">
+            <input class="usb-slider" type="range" id="usbMass" min="1" max="100" value="30">
+            <span class="usb-value" id="usbMassVal">30</span>
+        </div>
+    </div>
+
+    <div class="usb-sep"></div>
+
+    <!-- Zeitgeschwindigkeit -->
+    <div class="usb-toolbar-group">
+        <span class="usb-label">Zeit:</span>
+        <button class="usb-mode-btn" id="usbPause">⏸</button>
+        <button class="usb-mode-btn is-active" data-speed="1">1×</button>
+        <button class="usb-mode-btn" data-speed="5">5×</button>
+        <button class="usb-mode-btn" data-speed="20">20×</button>
+        <button class="usb-mode-btn" data-speed="100">100×</button>
+    </div>
+
+    <div class="usb-sep"></div>
+
+    <!-- Aktionen -->
+    <div class="usb-toolbar-group">
+        <button class="usb-mode-btn is-danger" id="usbReset">⟳ Zurücksetzen</button>
+        <button class="usb-mode-btn" id="usbPreset">☀ Sonnensystem</button>
+    </div>
+
+</div>
+
+<!-- ══════════════════════════════════════════════════════
+     3D-CANVAS
+═══════════════════════════════════════════════════════ -->
+<div class="usb-canvas-wrap mode-orbit" id="usbCanvasWrap">
+    <canvas id="usbCanvas"></canvas>
+
+    <div class="usb-hint" id="usbHint">Im Orbit-Modus: Ziehen = Drehen · Scroll = Zoomen · Platzieren-Modus: Klick = Körper setzen, Ziehen = Startgeschwindigkeit</div>
+
+    <!-- Info-Panel für selektierten Körper -->
+    <div class="usb-panel" id="usbPanel">
+        <h3 id="usbPanelTitle">Objekt</h3>
+        <div class="usb-panel-row"><span class="usb-panel-key">Masse</span><span class="usb-panel-val" id="piMass">—</span></div>
+        <div class="usb-panel-row"><span class="usb-panel-key">Radius</span><span class="usb-panel-val" id="piRadius">—</span></div>
+        <div class="usb-panel-row"><span class="usb-panel-key">Geschw.</span><span class="usb-panel-val" id="piVel">—</span></div>
+        <div class="usb-panel-row"><span class="usb-panel-key">Pos X</span><span class="usb-panel-val" id="piX">—</span></div>
+        <div class="usb-panel-row"><span class="usb-panel-key">Pos Y</span><span class="usb-panel-val" id="piY">—</span></div>
+        <div class="usb-panel-row"><span class="usb-panel-key">Pos Z</span><span class="usb-panel-val" id="piZ">—</span></div>
+    </div>
+
+    <div class="usb-hud" id="usbHud">
+        Körper: <span id="hudBodies">0</span> &nbsp;|&nbsp;
+        FPS: <span id="hudFps">—</span>
+    </div>
+</div>
+</div><!-- .usb-wrap -->
+
+<!-- Three.js + OrbitControls aus CDN -->
+<script src="https://cdnjs.cloudflare.com/ajax/libs/three.js/r128/three.min.js"></script>
+<script>
+// OrbitControls r128 inline (minimale, selbst enthalten)
+// Quelle: three.js examples/jsm/controls/OrbitControls.js — MIT-Lizenz
+// Hier als kompakter, direkter Einbau ohne Modul-System.
+</script>
+<script src="https://cdn.jsdelivr.net/npm/three@0.128.0/examples/js/controls/OrbitControls.js"></script>
+
+<script>
+(function () {
+'use strict';
+
+/* ═══════════════════════════════════════════════════════
+   KONFIGURATION
+═══════════════════════════════════════════════════════ */
+const G          = 6.674e-2;   // skalierte Gravitationskonstante
+const TRAIL_LEN  = 300;        // maximale Spurpunkte pro Körper
+const DT_BASE    = 0.016;      // Basis-Zeitschritt (Sekunden pro Frame)
+
+/* ═══════════════════════════════════════════════════════
+   THREE.JS SETUP
+═══════════════════════════════════════════════════════ */
+const wrap   = document.getElementById('usbCanvasWrap');
+const canvas = document.getElementById('usbCanvas');
+
+const renderer = new THREE.WebGLRenderer({ canvas, antialias: true });
+renderer.setPixelRatio(Math.min(window.devicePixelRatio, 2));
+renderer.setClearColor(0x000000, 1);
+
+const scene  = new THREE.Scene();
+const camera = new THREE.PerspectiveCamera(55, 1, 0.1, 50000);
+camera.position.set(0, 80, 250);
+
+const controls = new THREE.OrbitControls(camera, canvas);
+controls.enableDamping   = true;
+controls.dampingFactor   = 0.08;
+controls.enablePan       = false;
+controls.minDistance     = 10;
+controls.maxDistance     = 5000;
+
+// Schwaches Hintergrund-Sternfeld
+(function buildStarfield() {
+    const geo = new THREE.BufferGeometry();
+    const pos = [];
+    for (let i = 0; i < 3000; i++) {
+        const r = 4000;
+        pos.push(
+            (Math.random() - 0.5) * r,
+            (Math.random() - 0.5) * r,
+            (Math.random() - 0.5) * r
+        );
+    }
+    geo.setAttribute('position', new THREE.Float32BufferAttribute(pos, 3));
+    scene.add(new THREE.Points(geo, new THREE.PointsMaterial({ color: 0xffffff, size: 1.2, sizeAttenuation: false })));
+})();
+
+/* ═══════════════════════════════════════════════════════
+   SIMULATIONS-ZUSTAND
+═══════════════════════════════════════════════════════ */
+let bodies       = [];
+let simPaused    = false;
+let timeScale    = 1;
+let nextId       = 1;
+let selectedBody = null;
+
+// Placement-Drag-State
+let placing     = false;
+let placeStart  = null;   // {x,y} in NDC
+let placePos3D  = null;   // THREE.Vector3
+
+function hexToThree(hex) {
+    return new THREE.Color(hex);
+}
+
+/* ── Körper-Klasse ───────────────────────────────────── */
+class Body {
+    constructor(pos, vel, mass, color, type) {
+        this.id     = nextId++;
+        this.mass   = mass;
+        this.type   = type;         // 'star' | 'planet' | 'moon'
+        this.color  = color;
+        this.pos    = pos.clone();
+        this.vel    = vel.clone();
+        this.acc    = new THREE.Vector3();
+        this.trail  = [];           // ring-buffer of THREE.Vector3
+        this.alive  = true;
+
+        const radii = { star: 4, planet: 2.5, moon: 1.2 };
+        this.radius = radii[type] * Math.pow(mass / 30, 0.33);
+
+        // Three.js-Mesh
+        const geo  = new THREE.SphereGeometry(this.radius, 24, 16);
+        const mat  = new THREE.MeshStandardMaterial({ color: hexToThree(color), emissive: hexToThree(color), emissiveIntensity: type === 'star' ? 1.2 : 0.15 });
+        this.mesh  = new THREE.Mesh(geo, mat);
+        this.mesh.position.copy(pos);
+        scene.add(this.mesh);
+
+        // Licht für Sterne
+        if (type === 'star') {
+            this.light = new THREE.PointLight(hexToThree(color), 2, 800);
+            this.light.position.copy(pos);
+            scene.add(this.light);
+        }
+
+        // Spur (LineSegments)
+        const trailGeo = new THREE.BufferGeometry();
+        const trailPos = new Float32Array(TRAIL_LEN * 3);
+        trailGeo.setAttribute('position', new THREE.BufferAttribute(trailPos, 3));
+        trailGeo.setDrawRange(0, 0);
+        const trailMat = new THREE.LineBasicMaterial({ color: hexToThree(color), transparent: true, opacity: 0.4 });
+        this.trailLine = new THREE.Line(trailGeo, trailMat);
+        scene.add(this.trailLine);
+    }
+
+    addTrailPoint() {
+        this.trail.push(this.pos.clone());
+        if (this.trail.length > TRAIL_LEN) this.trail.shift();
+
+        const attr = this.trailLine.geometry.attributes.position;
+        for (let i = 0; i < this.trail.length; i++) {
+            attr.setXYZ(i, this.trail[i].x, this.trail[i].y, this.trail[i].z);
+        }
+        attr.needsUpdate = true;
+        this.trailLine.geometry.setDrawRange(0, this.trail.length);
+    }
+
+    destroy() {
+        scene.remove(this.mesh);
+        scene.remove(this.trailLine);
+        if (this.light) scene.remove(this.light);
+        this.mesh.geometry.dispose();
+        this.mesh.material.dispose();
+        this.trailLine.geometry.dispose();
+        this.trailLine.material.dispose();
+    }
+}
+
+/* ═══════════════════════════════════════════════════════
+   PHYSIK – Verlet-Integration (N-Body)
+═══════════════════════════════════════════════════════ */
+const _diff = new THREE.Vector3();
+
+function computeAccelerations() {
+    for (const b of bodies) b.acc.set(0, 0, 0);
+
+    for (let i = 0; i < bodies.length; i++) {
+        for (let j = i + 1; j < bodies.length; j++) {
+            const a = bodies[i], b = bodies[j];
+            _diff.subVectors(b.pos, a.pos);
+            const r2   = _diff.lengthSq();
+            const r    = Math.sqrt(r2);
+            const soft = 4;                  // Softening vermeidet Singularität
+            const f    = G * a.mass * b.mass / (r2 + soft * soft);
+            const dir  = _diff.clone().divideScalar(r);
+
+            a.acc.addScaledVector(dir,  f / a.mass);
+            b.acc.addScaledVector(dir, -f / b.mass);
+        }
+    }
+}
+
+function stepPhysics(dt) {
+    computeAccelerations();
+
+    for (const b of bodies) {
+        // Velocity Verlet
+        b.vel.addScaledVector(b.acc, dt * 0.5);
+        b.pos.addScaledVector(b.vel, dt);
+        b.vel.addScaledVector(b.acc, dt * 0.5);
+
+        b.mesh.position.copy(b.pos);
+        if (b.light) b.light.position.copy(b.pos);
+        b.addTrailPoint();
+    }
+
+    // Kollisionserkennung
+    for (let i = 0; i < bodies.length; i++) {
+        for (let j = i + 1; j < bodies.length; j++) {
+            const a = bodies[i], b = bodies[j];
+            if (!a.alive || !b.alive) continue;
+            const dist = a.pos.distanceTo(b.pos);
+            if (dist < (a.radius + b.radius) * 0.8) {
+                mergeBodies(a, b);
+            }
+        }
+    }
+
+    bodies = bodies.filter(b => {
+        if (!b.alive) { b.destroy(); return false; }
+        return true;
+    });
+}
+
+function mergeBodies(a, b) {
+    // Größerer Körper übernimmt — Impulserhaltung
+    const [big, small] = a.mass >= b.mass ? [a, b] : [b, a];
+    const totalMass = big.mass + small.mass;
+    big.vel.multiplyScalar(big.mass / totalMass).addScaledVector(small.vel, small.mass / totalMass);
+    big.mass   = totalMass;
+    big.radius = big.radius * Math.pow(totalMass / (big.mass || 1), 0.2);
+    big.mesh.geometry.dispose();
+    big.mesh.geometry = new THREE.SphereGeometry(big.radius, 24, 16);
+    small.alive = false;
+
+    if (selectedBody === small) selectedBody = big;
+}
+
+/* ═══════════════════════════════════════════════════════
+   PRESET — vereinfachtes Sonnensystem
+═══════════════════════════════════════════════════════ */
+function loadPreset() {
+    clearBodies();
+
+    // Sonne
+    addBody(new THREE.Vector3(0, 0, 0), new THREE.Vector3(0, 0, 0), 100, '#fffbe6', 'star');
+
+    // Planeten (Kreisbahnen: v = sqrt(G*M/r))
+    const planets = [
+        { r: 30,  m: 1,  color: '#aaaaff', type: 'planet' },  // Merkur-analog
+        { r: 50,  m: 3,  color: '#ffd966', type: 'planet' },  // Venus-analog
+        { r: 75,  m: 4,  color: '#4fc3d8', type: 'planet' },  // Erde-analog
+        { r: 105, m: 2,  color: '#ff9944', type: 'planet' },  // Mars-analog
+        { r: 160, m: 8,  color: '#ff7744', type: 'planet' },  // Jupiter-analog
+        { r: 220, m: 5,  color: '#c9a84c', type: 'planet' },  // Saturn-analog
+    ];
+
+    for (const p of planets) {
+        const angle = Math.random() * Math.PI * 2;
+        const px    = p.r * Math.cos(angle);
+        const pz    = p.r * Math.sin(angle);
+        const v     = Math.sqrt(G * 100 / p.r);
+        const vx    = -v * Math.sin(angle);
+        const vz    =  v * Math.cos(angle);
+        addBody(
+            new THREE.Vector3(px, 0, pz),
+            new THREE.Vector3(vx, 0, vz),
+            p.m, p.color, p.type
+        );
+    }
+}
+
+function addBody(pos, vel, mass, color, type) {
+    bodies.push(new Body(pos, vel, mass, color, type));
+    updateHud();
+}
+
+function clearBodies() {
+    for (const b of bodies) b.destroy();
+    bodies       = [];
+    selectedBody = null;
+    hidePanel();
+    updateHud();
+}
+
+/* ═══════════════════════════════════════════════════════
+   RESIZE
+═══════════════════════════════════════════════════════ */
+function onResize() {
+    const w = wrap.clientWidth;
+    const h = wrap.clientHeight;
+    renderer.setSize(w, h, false);
+    camera.aspect = w / h;
+    camera.updateProjectionMatrix();
+}
+window.addEventListener('resize', onResize);
+onResize();
+
+/* ═══════════════════════════════════════════════════════
+   PLATZIEREN – Mausinteraktion
+═══════════════════════════════════════════════════════ */
+let interactionMode = 'orbit';  // 'orbit' | 'place'
+let arrowHelper     = null;
+
+const raycaster  = new THREE.Raycaster();
+const placeplane = new THREE.Plane(new THREE.Vector3(0, 1, 0), 0); // xz-Ebene
+
+function ndcFromEvent(e) {
+    const rect = canvas.getBoundingClientRect();
+    return new THREE.Vector2(
+        ((e.clientX - rect.left) / rect.width)  * 2 - 1,
+        -((e.clientY - rect.top) / rect.height) * 2 + 1
+    );
+}
+
+function worldPosOnPlane(ndc) {
+    raycaster.setFromCamera(ndc, camera);
+    const target = new THREE.Vector3();
+    raycaster.ray.intersectPlane(placeplane, target);
+    return target;
+}
+
+canvas.addEventListener('mousedown', function (e) {
+    if (interactionMode !== 'place') return;
+    e.preventDefault();
+    placing    = true;
+    placeStart = ndcFromEvent(e);
+    placePos3D = worldPosOnPlane(placeStart);
+    controls.enabled = false;
+});
+
+canvas.addEventListener('mousemove', function (e) {
+    if (!placing) return;
+    const ndc    = ndcFromEvent(e);
+    const endPos = worldPosOnPlane(ndc);
+    if (!endPos || !placePos3D) return;
+
+    // Pfeil für Geschwindigkeitsrichtung
+    if (arrowHelper) scene.remove(arrowHelper);
+    const dir = endPos.clone().sub(placePos3D);
+    if (dir.length() > 0.5) {
+        arrowHelper = new THREE.ArrowHelper(dir.clone().normalize(), placePos3D, dir.length(), 0xffd966, 3, 2);
+        scene.add(arrowHelper);
+    }
+});
+
+canvas.addEventListener('mouseup', function (e) {
+    if (!placing) return;
+    placing = false;
+    controls.enabled = true;
+
+    const ndc    = ndcFromEvent(e);
+    const endPos = worldPosOnPlane(ndc);
+
+    if (arrowHelper) { scene.remove(arrowHelper); arrowHelper = null; }
+    if (!placePos3D) return;
+
+    const vel = endPos ? endPos.clone().sub(placePos3D).multiplyScalar(0.5) : new THREE.Vector3();
+    vel.y = 0;
+
+    const mass  = parseInt(document.getElementById('usbMass').value, 10);
+    const color = currentColor;
+    const type  = currentType;
+
+    addBody(placePos3D, vel, mass, color, type);
+});
+
+// Touch-Support (einfach)
+canvas.addEventListener('touchstart', function (e) {
+    if (interactionMode !== 'place' || e.touches.length !== 1) return;
+    const touch = e.touches[0];
+    placing    = true;
+    placeStart = ndcFromEvent(touch);
+    placePos3D = worldPosOnPlane(placeStart);
+    controls.enabled = false;
+}, { passive: true });
+
+canvas.addEventListener('touchend', function (e) {
+    if (!placing) return;
+    placing = false;
+    controls.enabled = true;
+    if (arrowHelper) { scene.remove(arrowHelper); arrowHelper = null; }
+    if (!placePos3D) return;
+    const mass  = parseInt(document.getElementById('usbMass').value, 10);
+    addBody(placePos3D, new THREE.Vector3(), mass, currentColor, currentType);
+}, { passive: true });
+
+/* ═══════════════════════════════════════════════════════
+   TOOLBAR INTERAKTION
+═══════════════════════════════════════════════════════ */
+let currentColor = '#fffbe6';
+let currentType  = 'star';
+
+// Modus-Buttons
+document.getElementById('usbModePlace').addEventListener('click', function () {
+    interactionMode = 'place';
+    wrap.className  = 'usb-canvas-wrap';
+    controls.enabled = false;
+    this.classList.add('is-active');
+    document.getElementById('usbModeOrbit').classList.remove('is-active');
+});
+document.getElementById('usbModeOrbit').addEventListener('click', function () {
+    interactionMode = 'orbit';
+    wrap.className  = 'usb-canvas-wrap mode-orbit';
+    controls.enabled = true;
+    placing = false;
+    if (arrowHelper) { scene.remove(arrowHelper); arrowHelper = null; }
+    this.classList.add('is-active');
+    document.getElementById('usbModePlace').classList.remove('is-active');
+});
+
+// Typ-Buttons
+document.querySelectorAll('[data-type]').forEach(function (btn) {
+    btn.addEventListener('click', function () {
+        document.querySelectorAll('[data-type]').forEach(b => b.classList.remove('is-active'));
+        this.classList.add('is-active');
+        currentType = this.dataset.type;
+    });
+});
+
+// Farb-Swatches
+document.querySelectorAll('.usb-swatch').forEach(function (sw) {
+    sw.addEventListener('click', function () {
+        document.querySelectorAll('.usb-swatch').forEach(s => s.classList.remove('active'));
+        this.classList.add('active');
+        currentColor = this.dataset.color;
+    });
+});
+
+// Masse-Slider
+const massSlider = document.getElementById('usbMass');
+const massVal    = document.getElementById('usbMassVal');
+massSlider.addEventListener('input', function () { massVal.textContent = this.value; });
+
+// Zeit-Buttons
+document.querySelectorAll('[data-speed]').forEach(function (btn) {
+    btn.addEventListener('click', function () {
+        document.querySelectorAll('[data-speed]').forEach(b => b.classList.remove('is-active'));
+        this.classList.add('is-active');
+        timeScale  = parseFloat(this.dataset.speed);
+        simPaused  = false;
+        document.getElementById('usbPause').textContent = '⏸';
+    });
+});
+
+document.getElementById('usbPause').addEventListener('click', function () {
+    simPaused = !simPaused;
+    this.textContent = simPaused ? '▶' : '⏸';
+});
+
+document.getElementById('usbReset').addEventListener('click', clearBodies);
+document.getElementById('usbPreset').addEventListener('click', loadPreset);
+
+/* ═══════════════════════════════════════════════════════
+   HUD & PANEL
+═══════════════════════════════════════════════════════ */
+function updateHud() {
+    document.getElementById('hudBodies').textContent = bodies.length;
+}
+
+function showPanel(b) {
+    selectedBody = b;
+    const panel  = document.getElementById('usbPanel');
+    panel.classList.add('is-visible');
+    document.getElementById('usbPanelTitle').textContent = b.type.charAt(0).toUpperCase() + b.type.slice(1) + ' #' + b.id;
+}
+
+function hidePanel() {
+    document.getElementById('usbPanel').classList.remove('is-visible');
+}
+
+function updatePanel() {
+    if (!selectedBody || !selectedBody.alive) { hidePanel(); return; }
+    const b = selectedBody;
+    document.getElementById('piMass').textContent   = b.mass.toFixed(1);
+    document.getElementById('piRadius').textContent = b.radius.toFixed(2);
+    document.getElementById('piVel').textContent    = b.vel.length().toFixed(2);
+    document.getElementById('piX').textContent      = b.pos.x.toFixed(1);
+    document.getElementById('piY').textContent      = b.pos.y.toFixed(1);
+    document.getElementById('piZ').textContent      = b.pos.z.toFixed(1);
+}
+
+// Klick auf Körper für Panel-Auswahl
+canvas.addEventListener('click', function (e) {
+    if (interactionMode !== 'orbit') return;
+    const ndc = ndcFromEvent(e);
+    raycaster.setFromCamera(ndc, camera);
+    const meshes = bodies.map(b => b.mesh);
+    const hits   = raycaster.intersectObjects(meshes);
+    if (hits.length) {
+        const hit = hits[0].object;
+        const b   = bodies.find(b => b.mesh === hit);
+        if (b) showPanel(b);
+    } else {
+        hidePanel();
+        selectedBody = null;
+    }
+});
+
+/* ═══════════════════════════════════════════════════════
+   AMBIENTES LICHT
+═══════════════════════════════════════════════════════ */
+scene.add(new THREE.AmbientLight(0x111122, 0.8));
+
+/* ═══════════════════════════════════════════════════════
+   RENDER-LOOP
+═══════════════════════════════════════════════════════ */
+let lastTime = performance.now();
+let fps = 0, fpsCounter = 0, fpsClock = 0;
+
+function animate(now) {
+    requestAnimationFrame(animate);
+
+    const elapsed = (now - lastTime) / 1000;
+    lastTime = now;
+
+    // FPS
+    fpsCounter++;
+    fpsClock += elapsed;
+    if (fpsClock >= 0.5) {
+        fps = Math.round(fpsCounter / fpsClock);
+        document.getElementById('hudFps').textContent = fps;
+        fpsCounter = 0; fpsClock = 0;
+    }
+
+    // Physik
+    if (!simPaused && bodies.length > 0) {
+        const dt    = Math.min(elapsed, 0.05) * timeScale;
+        const steps = Math.max(1, Math.round(timeScale / 5));
+        const subDt = dt / steps;
+        for (let i = 0; i < steps; i++) stepPhysics(subDt);
+        updateHud();
+    }
+
+    controls.update();
+    updatePanel();
+
+    renderer.render(scene, camera);
+}
+
+// Hint nach 5 Sekunden ausblenden
+setTimeout(function () {
+    const h = document.getElementById('usbHint');
+    if (h) h.style.opacity = '0';
+}, 5000);
+
+// Standard: Orbit-Modus + Preset laden
+loadPreset();
+animate(performance.now());
+
+})();
+</script>
+
+<?php require __DIR__ . '/footer.php'; ?>