Add marketing website for SatsPrice

Static, dark-themed landing page showcasing the app's capabilities with
real screenshots for Android, iOS, iPad, and macOS, plus download links
for all supported distribution channels.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AejmWBrdE3DbJWbXoaE3aX

website/script.js

@@ -0,0 +1,56 @@
+// Mobile nav toggle
+const navToggle = document.querySelector(".nav-toggle");
+const mobileNav = document.querySelector(".mobile-nav");
+
+if (navToggle && mobileNav) {
+  navToggle.addEventListener("click", () => {
+    mobileNav.classList.toggle("open");
+  });
+
+  mobileNav.querySelectorAll("a").forEach((link) => {
+    link.addEventListener("click", () => mobileNav.classList.remove("open"));
+  });
+}
+
+// Platform showcase tabs
+const tabButtons = document.querySelectorAll(".tab-btn");
+const tabPanels = document.querySelectorAll(".tab-panel");
+
+tabButtons.forEach((btn) => {
+  btn.addEventListener("click", () => {
+    const target = btn.getAttribute("data-tab");
+
+    tabButtons.forEach((b) => b.classList.remove("active"));
+    tabPanels.forEach((p) => p.classList.remove("active"));
+
+    btn.classList.add("active");
+    document.getElementById(target).classList.add("active");
+  });
+});
+
+// Simulated live BTC price ticker (cosmetic only, not a real feed)
+(function priceTicker() {
+  const valueEl = document.querySelector(".ticker .tk-value");
+  const subEl = document.querySelector(".ticker .tk-sub");
+  if (!valueEl) return;
+
+  let price = 77300;
+
+  function format(n) {
+    return n.toLocaleString("en-US", { maximumFractionDigits: 0 });
+  }
+
+  function tick() {
+    price += (Math.random() - 0.5) * 60;
+    valueEl.textContent = "$" + format(price);
+    const sats = Math.round(100000000 / price);
+    subEl.textContent = "1 USD ≈ " + sats.toLocaleString("en-US") + " sats";
+  }
+
+  tick();
+  setInterval(tick, 2200);
+})();
+
+// Footer year
+const yearEl = document.getElementById("year");
+if (yearEl) yearEl.textContent = new Date().getFullYear();