feat: Add new year promo

.vscode/settings.json

@@ -16,6 +16,7 @@
     "localstorage",
     "mermaidchart",
     "mindmap",
+    "NEWYEAR",
     "Pageview",
     "pako",
     "panmove",

src/lib/util/promos/NewYear2026.svelte

@@ -0,0 +1,78 @@
+<script lang="ts">
+  import { Button } from '$/components/ui/button';
+  import { env } from '$/util/env';
+  import type { Snippet } from 'svelte';
+
+  interface Props {
+    closeBanner: Snippet;
+  }
+
+  let { closeBanner }: Props = $props();
+
+  interface VariantConfig {
+    bannerCopy: string;
+    buttonCopy: string;
+    campaign: 'variant_a' | 'variant_b' | 'variant_c';
+  }
+
+  const variants: VariantConfig[] = [
+    {
+      bannerCopy: 'Use code NEWYEAR for 10% off Mermaid Advanced Editor (limited time)',
+      buttonCopy: 'Try now',
+      campaign: 'variant_a'
+    },
+    {
+      bannerCopy: 'Limited time: 10% off Mermaid Advanced Editor with code NEWYEAR',
+      buttonCopy: 'Claim discount',
+      campaign: 'variant_b'
+    },
+    {
+      bannerCopy: 'Try Mermaid Advanced Editor — get 10% off with code NEWYEAR',
+      buttonCopy: 'Get started',
+      campaign: 'variant_c'
+    }
+  ];
+
+  // Determine UTM source based on deployment domain
+  const getUtmSource = (): string => {
+    const domain = env.domain;
+    if (domain === 'mermaid.ai') {
+      return 'mermaid_ai_live';
+    }
+    return 'mermaid_live_editor';
+  };
+
+  // Randomly select a variant on component mount
+  const getRandomVariant = (): VariantConfig => {
+    const index = Math.floor(Math.random() * variants.length);
+    return variants[index];
+  };
+
+  const selectedVariant = getRandomVariant();
+  const utmSource = getUtmSource();
+
+  const buildUrl = (variant: VariantConfig): string => {
+    const params = new URLSearchParams({
+      utm_medium: 'banner_ad',
+      utm_campaign: variant.campaign,
+      utm_source: utmSource
+    });
+    return `https://mermaid.ai/?${params.toString()}`;
+  };
+</script>
+
+<div class="flex w-full items-center bg-[#E0095F] p-1.5" role="banner">
+  <div class="grid grow">
+    <a
+      href={buildUrl(selectedVariant)}
+      target="_blank"
+      class="col-start-1 row-start-1 flex items-center justify-center gap-4 no-underline">
+      <span class="text-base tracking-wider text-white">{selectedVariant.bannerCopy}</span>
+      <Button
+        class="shrink-0 rounded-md bg-[#1E1A2E] px-3 py-1.5 text-base font-semibold tracking-wide text-white hover:bg-[#261A56]">
+        {selectedVariant.buttonCopy}
+      </Button>
+    </a>
+  </div>
+  {@render closeBanner()}
+</div>

src/lib/util/promos/promo.ts

@@ -5,6 +5,7 @@ import type { Component } from 'svelte';
 import { get, writable, type Writable } from 'svelte/store';
 import { localStorage, persist } from '../persist';
 import April2025 from './April2025.svelte';
+import NewYear2026 from './NewYear2026.svelte';
 
 dayjs.extend(duration);
 
@@ -16,6 +17,12 @@ interface Promotion {
 }
 
 const promotions: Record<string, Promotion> = {
+  'promo-newyear-2026': {
+    startDate: new Date('2026-01-01'),
+    endDate: new Date('2026-03-14'),
+    component: NewYear2026,
+    hideDurationMs: dayjs.duration(1, 'week').asMilliseconds()
+  },
   'promo-april-2025': {
     startDate: new Date('2025-04-01'),
     endDate: new Date('2028-12-31'),