*, *::before, *::after {
  box-sizing: border-box;
}

body {
  font-family: system-ui, "Segoe UI", Roboto, Helvetica, Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol";
  margin: 0;
  background: #0f172a;
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  overflow: hidden;
}

.elastic-container {
  position: relative;
  width: 100%;
  max-width: 1000px;
  height: 500px;
  display: flex;
  justify-content: center;
  align-items: center;
}

.content-overlay {
  position: absolute;
  top: 60px;
  text-align: center;
  color: #ffffff;
  pointer-events: none;
  z-index: 10;
}

.content-overlay h2 {
  font-size: 2.5rem;
  margin: 0 0 10px 0;
  letter-spacing: -1px;
}

.content-overlay p {
  color: #94a3b8;
  font-size: 1.125rem;
  margin: 0;
}

.svg-wrapper {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 1;
  cursor: grab;
}

.svg-wrapper:active {
  cursor: grabbing;
}

#elastic-line {
  filter: drop-shadow(0 0 15px rgba(59, 130, 246, 0.8));
}

const wrapper = document.getElementById("string-wrapper");
const line = document.getElementById("elastic-line");

let isDragging = false;
let mouseX = 500;
let mouseY = 250;

let currentY = 250;
let targetY = 250;
let velocity = 0;

// Physics constants
const tension = 0.05;
const friction = 0.85;

wrapper.addEventListener("pointerdown", function(e) {
  isDragging = true;
  wrapper.setPointerCapture(e.pointerId);
  updateMousePos(e);
});

wrapper.addEventListener("pointermove", function(e) {
  if (isDragging) {
    updateMousePos(e);
  }
});

function endDrag() {
  isDragging = false;
  targetY = 250;
  mouseX = 500;
}

wrapper.addEventListener("pointerup", endDrag);
wrapper.addEventListener("pointercancel", endDrag);

function updateMousePos(e) {
  const rect = wrapper.getBoundingClientRect();
  // Map mouse position to the 1000x500 SVG viewBox
  mouseX = (e.clientX - rect.left) * (1000 / rect.width);
  let rawY = (e.clientY - rect.top) * (500 / rect.height);
  
  targetY = rawY;
}

function animate() {
  if (!isDragging) {
    // Spring physics calculation
    const force = (targetY - currentY) * tension;
    velocity += force;
    velocity *= friction;
    currentY += velocity;
  } else {
    // Follow mouse smoothly when dragging
    currentY += (targetY - currentY) * 0.5;
  }
  
  // Update the Quadratic Bezier Curve path
  line.setAttribute("d", "M 0 250 Q " + mouseX + " " + currentY + " 1000 250");
  
  window.requestAnimationFrame(animate);
}

animate();