Snow

src/lib/components/Snowfall.svelte

@@ -0,0 +1,127 @@
+<script lang="ts">
+    import { onDestroy, onMount } from 'svelte';
+
+    let canvas: HTMLCanvasElement;
+    let ctx: CanvasRenderingContext2D | null = null;
+    let width = 0;
+    let height = 0;
+    let dpr = 1;
+    let raf = 0;
+
+    interface Flake {
+        x: number;
+        y: number;
+        r: number;
+        vx: number;
+        vy: number;
+        phase: number;
+        opacity: number;
+    }
+
+    let flakes: Flake[] = [];
+
+    function makeFlake(): Flake {
+        const r = Math.random() * 2.2 + 0.8; // 0.8 - 3.0 px
+        const speed = 0.4 + r * 0.35; // tie speed to size
+        return {
+            x: Math.random() * width,
+            y: -10 - Math.random() * height,
+            r,
+            vx: (Math.random() - 0.5) * 0.4,
+            vy: speed,
+            phase: Math.random() * Math.PI * 2,
+            opacity: 0.6 + Math.random() * 0.4
+        };
+    }
+
+    function setCanvasSize() {
+        width = window.innerWidth;
+        height = window.innerHeight;
+        canvas.width = Math.floor(width * dpr);
+        canvas.height = Math.floor(height * dpr);
+        canvas.style.width = width + 'px';
+        canvas.style.height = height + 'px';
+        ctx && ctx.setTransform(dpr, 0, 0, dpr, 0, 0);
+    }
+
+    function populateFlakes(target: number) {
+        flakes.length = 0;
+        for (let i = 0; i < target; i++) {
+            const f = makeFlake();
+            f.y = Math.random() * height;
+            flakes.push(f);
+        }
+    }
+
+    function draw() {
+        if (!ctx) return;
+        ctx.clearRect(0, 0, width, height);
+        ctx.fillStyle = '#fff';
+        for (const f of flakes) {
+            f.phase += 0.01 + f.r * 0.002;
+            f.x += f.vx + Math.sin(f.phase) * 0.3;
+            f.y += f.vy;
+
+            if (f.y - f.r > height) {
+                f.x = Math.random() * width;
+                f.y = -f.r - Math.random() * 40;
+                f.vx = (Math.random() - 0.5) * 0.4;
+                f.phase = Math.random() * Math.PI * 2;
+            }
+
+            ctx.globalAlpha = f.opacity;
+            ctx.beginPath();
+            ctx.arc(f.x, f.y, f.r, 0, Math.PI * 2);
+            ctx.fill();
+        }
+        ctx.globalAlpha = 1;
+    }
+
+    function loop() {
+        draw();
+        raf = requestAnimationFrame(loop);
+    }
+
+    function handleResize() {
+        setCanvasSize();
+        const density = Math.min(220, Math.max(60, Math.floor((width * height) / 15000)));
+        populateFlakes(density);
+    }
+
+    onMount(() => {
+        if (typeof window === 'undefined') return;
+        dpr = Math.min(2, window.devicePixelRatio || 1);
+        ctx = canvas.getContext('2d');
+        if (!ctx) return;
+        setCanvasSize();
+        handleResize();
+        window.addEventListener('resize', handleResize, { passive: true });
+        raf = requestAnimationFrame(loop);
+        return () => {
+            if (typeof cancelAnimationFrame === 'function') cancelAnimationFrame(raf);
+            window.removeEventListener('resize', handleResize);
+        };
+    });
+
+    onDestroy(() => {
+        if (typeof cancelAnimationFrame === 'function') cancelAnimationFrame(raf);
+        if (typeof window !== 'undefined') window.removeEventListener('resize', handleResize);
+    });
+</script>
+
+<style>
+    canvas {
+        position: fixed;
+        inset: 0;
+        width: 100%;
+        height: 100%;
+        pointer-events: none;
+        z-index: 0;
+        filter: drop-shadow(0 0 2px rgba(255, 255, 255, 0.6));
+    }
+    @media (prefers-reduced-motion: reduce) {
+        canvas { display: none; }
+    }
+</style>
+
+<canvas bind:this={canvas} aria-hidden="true"></canvas>

src/routes/+layout.svelte

@@ -1,7 +1,26 @@
 <script lang="ts">
 	import '../app.css';
+	import Snowfall from '$lib/components/Snowfall.svelte';
 
 	let { children } = $props();
 </script>
 
-{@render children?.()}
+<Snowfall />
+
+<div class="app-content">
+	{@render children?.()}
+</div>
+
+<style>
+	.app-content {
+		position: relative;
+		z-index: 1;
+		min-height: 100dvh;
+	}
+	:global(html, body) {
+		min-height: 100%;
+	}
+	:global(body) {
+		position: relative;
+	}
+</style>