diff --git a/README.md b/README.md
index 3604f24..c50dca6 100644
--- a/README.md
+++ b/README.md
@@ -36,22 +36,27 @@ accounts, playlists, live recording, or multiple simultaneous downloads.
 
 ## Development stages
 
-1. Create a minimal containerized web application with a health check.
-2. Inspect a URL and display sanitized source metadata and formats.
-3. Add a durable job queue and separate worker.
-4. Download media and report progress.
-5. Add original-quality and compatible-MP4 output modes.
-6. Add cleanup, limits, failure handling, and security tests.
-7. Validate the complete local Docker deployment.
-8. Deploy privately to the VPS through Cloudflare Access and Tunnel.
+- [x] Create a minimal containerized web application with a health check.
+- [x] Inspect a URL and display sanitized source metadata and formats.
+- [x] Add a dark, responsive inspection interface.
+- [ ] Define download presets and their exact yt-dlp selectors.
+- [ ] Add a durable job queue and separate worker.
+- [ ] Download media and report progress.
+- [ ] Add cleanup, limits, failure handling, and security tests.
+- [ ] Validate the complete local Docker deployment.
+- [ ] Deploy privately to the VPS through Cloudflare Access and Tunnel.
 
 Each stage should produce a small, working, reviewable commit.
 
 ## Local development
 
-The current milestone is a minimal FastAPI application running in a hardened
-local container. Docker publishes it only on the PC's loopback interface, so it
-is not exposed to other devices on the LAN.
+The current milestone provides a browser interface for inspecting public video
+sources. It shows normalized source metadata and previews best-available and
+compatible-MP4 outcomes. Download jobs are not implemented yet.
+
+The application runs as a non-root user in a read-only container with Linux
+capabilities dropped. Docker publishes it only on the PC's loopback interface,
+so it is not exposed to other devices on the LAN.
 
 Build and start it:
 
@@ -85,6 +90,10 @@ hostname must resolve entirely to public IP addresses. Playlists and
 multi-video sources are rejected, and raw signed media URLs are not returned
 to the browser.
 
+The initial URL validation is not yet a complete SSRF defense. Do not expose
+this development build to the Internet. See [`docs/SECURITY.md`](docs/SECURITY.md)
+for the implemented boundary and work required before deployment.
+
 Run the automated tests in an ephemeral container:
 
 ```bash
@@ -107,6 +116,11 @@ The original project discussion is retained in
 that affect the implementation will be documented in this repository rather
 than relying on that discussion alone.
 
+- [`docs/ARCHITECTURE.md`](docs/ARCHITECTURE.md) describes the current and
+  planned application structure.
+- [`docs/SECURITY.md`](docs/SECURITY.md) tracks the trust boundary and
+  pre-deployment requirements.
+
 ## Responsible use
 
 This tool is intended for material the operator is authorized to retrieve and
diff --git a/app/main.py b/app/main.py
index 1c30728..4e893b1 100644
--- a/app/main.py
+++ b/app/main.py
@@ -1,5 +1,11 @@
+from pathlib import Path
+
 from fastapi import FastAPI
 from fastapi import HTTPException
+from fastapi import Request
+from fastapi.responses import HTMLResponse
+from fastapi.staticfiles import StaticFiles
+from fastapi.templating import Jinja2Templates
 from starlette.concurrency import run_in_threadpool
 
 from app.inspection import InspectionError, UnsafeUrlError, inspect_url
@@ -11,10 +17,14 @@ app = FastAPI(
     version="0.1.0",
 )
 
+app_directory = Path(__file__).resolve().parent
+templates = Jinja2Templates(directory=app_directory / "templates")
+app.mount("/static", StaticFiles(directory=app_directory / "static"), name="static")
 
-@app.get("/", tags=["system"])
-def root() -> dict[str, str]:
-    return {"name": "Media Ingest", "status": "running"}
+
+@app.get("/", response_class=HTMLResponse, include_in_schema=False)
+def index(request: Request) -> HTMLResponse:
+    return templates.TemplateResponse(request=request, name="index.html")
 
 
 @app.get("/health", tags=["system"])
diff --git a/app/static/app.js b/app/static/app.js
new file mode 100644
index 0000000..3c9cee9
--- /dev/null
+++ b/app/static/app.js
@@ -0,0 +1,212 @@
+const form = document.querySelector("#inspect-form");
+const urlInput = document.querySelector("#source-url");
+const submitButton = document.querySelector("#inspect-button");
+const errorNotice = document.querySelector("#error-notice");
+const errorMessage = document.querySelector("#error-message");
+const resultSection = document.querySelector("#result");
+const heroSection = document.querySelector(".hero");
+const newSourceButton = document.querySelector("#new-source");
+const reducedMotion = window.matchMedia("(prefers-reduced-motion: reduce)");
+
+const fields = {
+  title: document.querySelector("#result-title"),
+  sourceLink: document.querySelector("#source-link"),
+  thumbnail: document.querySelector("#thumbnail"),
+  thumbnailShell: document.querySelector("#thumbnail-shell"),
+  duration: document.querySelector("#duration"),
+  extractor: document.querySelector("#extractor"),
+  uploader: document.querySelector("#uploader"),
+  uploadDate: document.querySelector("#upload-date"),
+  topQuality: document.querySelector("#top-quality"),
+  bestSpecs: document.querySelector("#best-specs"),
+  compatibleOption: document.querySelector("#compatible-option"),
+  compatibleSpecs: document.querySelector("#compatible-specs"),
+};
+
+function displayValue(value, fallback = "Not available") {
+  return value === null || value === undefined || value === "" ? fallback : String(value);
+}
+
+function formatDuration(seconds) {
+  if (!Number.isFinite(seconds)) return "Unknown duration";
+  const total = Math.max(0, Math.round(seconds));
+  const hours = Math.floor(total / 3600);
+  const minutes = Math.floor((total % 3600) / 60);
+  const remainingSeconds = total % 60;
+  const parts = hours > 0 ? [hours, minutes, remainingSeconds] : [minutes, remainingSeconds];
+  return parts.map((part) => String(part).padStart(2, "0")).join(":");
+}
+
+function formatUploadDate(value) {
+  if (!/^\d{8}$/.test(value || "")) return displayValue(value);
+  return `${value.slice(0, 4)}-${value.slice(4, 6)}-${value.slice(6, 8)}`;
+}
+
+function resolutionLabel(format) {
+  if (format.width && format.height) return `${format.width} × ${format.height}`;
+  if (format.audio_codec && format.audio_codec !== "none") return "Audio only";
+  return "Unknown";
+}
+
+function isVideo(format) {
+  return format.video_codec && format.video_codec !== "none";
+}
+
+function isAudio(format) {
+  return format.audio_codec && format.audio_codec !== "none";
+}
+
+function sortByVisualQuality(formats) {
+  return [...formats].sort((left, right) => {
+    return (right.height || 0) - (left.height || 0) || (right.fps || 0) - (left.fps || 0);
+  });
+}
+
+function codecFamily(codec) {
+  if (!codec || codec === "none") return null;
+  const normalized = codec.toLowerCase();
+  if (normalized.startsWith("avc") || normalized === "h264") return "H.264";
+  if (normalized.startsWith("av01")) return "AV1";
+  if (normalized.startsWith("vp9") || normalized.startsWith("vp09")) return "VP9";
+  if (normalized.startsWith("mp4a") || normalized === "aac") return "AAC";
+  if (normalized.startsWith("opus")) return "Opus";
+  return codec;
+}
+
+function addSpec(list, label, value) {
+  const wrapper = document.createElement("div");
+  const term = document.createElement("dt");
+  const detail = document.createElement("dd");
+  term.textContent = label;
+  detail.textContent = value;
+  wrapper.append(term, detail);
+  list.append(wrapper);
+}
+
+function renderOption(list, video, audio) {
+  list.replaceChildren();
+  addSpec(list, "Quality", resolutionLabel(video));
+  if (video.fps) addSpec(list, "FPS", String(video.fps));
+  addSpec(list, "Video", displayValue(codecFamily(video.video_codec), "Unknown"));
+  const audioCodec = isAudio(video) ? video.audio_codec : audio?.audio_codec;
+  addSpec(list, "Audio", displayValue(codecFamily(audioCodec), "Unknown"));
+}
+
+function renderOutputOptions(formats) {
+  const orderedVideo = sortByVisualQuality(formats.filter(isVideo));
+  const audioOnly = formats.filter((format) => !isVideo(format) && isAudio(format));
+  const bestVideo = orderedVideo[0];
+  const bestAudio = audioOnly.at(-1);
+
+  if (!bestVideo) {
+    fields.topQuality.textContent = "Audio only";
+    fields.bestSpecs.replaceChildren();
+    fields.compatibleOption.hidden = true;
+    return;
+  }
+
+  fields.topQuality.textContent = resolutionLabel(bestVideo);
+  renderOption(fields.bestSpecs, bestVideo, bestAudio);
+
+  const compatibleVideo = orderedVideo.find((format) => {
+    const videoCodec = codecFamily(format.video_codec);
+    const audioCodec = codecFamily(format.audio_codec);
+    return videoCodec === "H.264" && (!isAudio(format) || audioCodec === "AAC");
+  });
+  const compatibleAudio = audioOnly.findLast((format) => codecFamily(format.audio_codec) === "AAC");
+
+  if (compatibleVideo && (isAudio(compatibleVideo) || compatibleAudio)) {
+    renderOption(fields.compatibleSpecs, compatibleVideo, compatibleAudio);
+    fields.compatibleOption.hidden = false;
+  } else {
+    fields.compatibleOption.hidden = true;
+  }
+}
+
+function renderResult(data) {
+  fields.title.textContent = data.title;
+  fields.sourceLink.href = data.source_url;
+  fields.extractor.textContent = displayValue(data.extractor);
+  fields.uploader.textContent = displayValue(data.uploader);
+  fields.uploadDate.textContent = formatUploadDate(data.upload_date);
+  fields.duration.textContent = formatDuration(data.duration);
+
+  if (data.thumbnail) {
+    fields.thumbnail.src = data.thumbnail;
+    fields.thumbnail.alt = `Preview for ${data.title}`;
+    fields.thumbnail.hidden = false;
+    fields.thumbnailShell.classList.remove("no-image");
+  } else {
+    fields.thumbnail.removeAttribute("src");
+    fields.thumbnail.alt = "";
+    fields.thumbnail.hidden = true;
+    fields.thumbnailShell.classList.add("no-image");
+  }
+
+  renderOutputOptions(data.formats);
+}
+
+function transitionDelay(milliseconds) {
+  return new Promise((resolve) => {
+    window.setTimeout(resolve, reducedMotion.matches ? 0 : milliseconds);
+  });
+}
+
+async function showResult(data) {
+  renderResult(data);
+  heroSection.classList.add("is-leaving");
+  await transitionDelay(180);
+  heroSection.hidden = true;
+  heroSection.classList.remove("is-leaving");
+  resultSection.hidden = false;
+  window.scrollTo({ top: 0, behavior: "auto" });
+  window.requestAnimationFrame(() => resultSection.classList.add("is-visible"));
+}
+
+async function showInspector() {
+  resultSection.classList.remove("is-visible");
+  resultSection.classList.add("is-leaving");
+  await transitionDelay(180);
+  resultSection.hidden = true;
+  resultSection.classList.remove("is-leaving");
+  heroSection.classList.add("is-leaving");
+  heroSection.hidden = false;
+  window.requestAnimationFrame(() => {
+    heroSection.classList.remove("is-leaving");
+    urlInput.focus();
+  });
+}
+
+function setLoading(isLoading) {
+  submitButton.disabled = isLoading;
+  urlInput.disabled = isLoading;
+  form.setAttribute("aria-busy", String(isLoading));
+}
+
+form.addEventListener("submit", async (event) => {
+  event.preventDefault();
+  errorNotice.hidden = true;
+  resultSection.hidden = true;
+  setLoading(true);
+
+  try {
+    const response = await fetch("/api/inspect", {
+      method: "POST",
+      headers: { "Content-Type": "application/json" },
+      body: JSON.stringify({ url: urlInput.value.trim() }),
+    });
+    const data = await response.json();
+
+    if (!response.ok) {
+      throw new Error(data.detail || "The source could not be inspected.");
+    }
+    await showResult(data);
+  } catch (error) {
+    errorMessage.textContent = error instanceof Error ? error.message : "Inspection failed.";
+    errorNotice.hidden = false;
+  } finally {
+    setLoading(false);
+  }
+});
+
+newSourceButton.addEventListener("click", showInspector);
diff --git a/app/static/styles.css b/app/static/styles.css
new file mode 100644
index 0000000..d6e05a1
--- /dev/null
+++ b/app/static/styles.css
@@ -0,0 +1,588 @@
+:root {
+  color-scheme: dark;
+  --background: #090a0c;
+  --surface: #101216;
+  --surface-raised: #15181d;
+  --border: #242830;
+  --border-strong: #363c47;
+  --text: #f1f3f5;
+  --muted: #9299a4;
+  --quiet: #626974;
+  --accent: #d9ff43;
+  --accent-text: #111408;
+  --danger: #ff6b6b;
+  --radius: 14px;
+  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
+  font-synthesis: none;
+}
+
+* {
+  box-sizing: border-box;
+}
+
+html {
+  background: var(--background);
+}
+
+body {
+  min-width: 320px;
+  margin: 0;
+  color: var(--text);
+  background:
+    radial-gradient(circle at 50% -20%, rgba(217, 255, 67, 0.07), transparent 34rem),
+    var(--background);
+}
+
+button,
+input {
+  font: inherit;
+}
+
+a {
+  color: inherit;
+}
+
+.site-header,
+.page-shell,
+footer {
+  width: min(1180px, calc(100% - 40px));
+  margin-inline: auto;
+}
+
+.site-header {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  min-height: 76px;
+  border-bottom: 1px solid var(--border);
+}
+
+.brand {
+  display: inline-flex;
+  gap: 10px;
+  align-items: center;
+  color: var(--text);
+  font-size: 13px;
+  font-weight: 650;
+  letter-spacing: 0.08em;
+  text-decoration: none;
+  text-transform: uppercase;
+}
+
+.brand-mark {
+  width: 8px;
+  height: 8px;
+  background: var(--accent);
+  border-radius: 2px;
+  box-shadow: 0 0 16px rgba(217, 255, 67, 0.45);
+}
+
+.environment {
+  padding: 6px 9px;
+  color: var(--muted);
+  border: 1px solid var(--border);
+  border-radius: 999px;
+  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
+  font-size: 10px;
+  letter-spacing: 0.12em;
+  text-transform: uppercase;
+}
+
+.page-shell {
+  min-height: calc(100vh - 142px);
+}
+
+.hero {
+  max-width: 900px;
+  padding: 104px 0 82px;
+  transition: opacity 180ms ease, transform 180ms ease;
+}
+
+.hero.is-leaving {
+  opacity: 0;
+  transform: translateY(-10px);
+}
+
+.eyebrow {
+  margin: 0 0 18px;
+  color: var(--accent);
+  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
+  font-size: 11px;
+  font-weight: 700;
+  letter-spacing: 0.14em;
+  text-transform: uppercase;
+}
+
+h1,
+h2,
+h3,
+p {
+  text-wrap: pretty;
+}
+
+h1 {
+  max-width: 780px;
+  margin: 0;
+  font-size: clamp(42px, 6vw, 74px);
+  font-weight: 560;
+  letter-spacing: -0.055em;
+  line-height: 0.98;
+}
+
+.intro {
+  max-width: 590px;
+  margin: 30px 0 0;
+  color: var(--muted);
+  font-size: 16px;
+  line-height: 1.7;
+}
+
+.inspect-form {
+  margin-top: 48px;
+}
+
+.input-shell {
+  display: grid;
+  grid-template-columns: 1fr auto;
+  gap: 10px;
+  padding: 8px;
+  background: var(--surface);
+  border: 1px solid var(--border-strong);
+  border-radius: var(--radius);
+  transition: border-color 160ms ease, box-shadow 160ms ease;
+}
+
+.input-shell:focus-within {
+  border-color: #59626f;
+  box-shadow: 0 0 0 3px rgba(217, 255, 67, 0.08);
+}
+
+input {
+  min-width: 0;
+  padding: 15px 14px;
+  color: var(--text);
+  background: transparent;
+  border: 0;
+  outline: 0;
+}
+
+input::placeholder {
+  color: var(--quiet);
+}
+
+button {
+  position: relative;
+  min-width: 142px;
+  padding: 13px 18px;
+  color: var(--accent-text);
+  font-size: 13px;
+  font-weight: 700;
+  background: var(--accent);
+  border: 0;
+  border-radius: 9px;
+  cursor: pointer;
+  transition: filter 140ms ease, transform 140ms ease;
+}
+
+button:hover {
+  filter: brightness(0.92);
+}
+
+button:active {
+  transform: translateY(1px);
+}
+
+button:disabled {
+  color: transparent;
+  cursor: wait;
+  filter: saturate(0.6);
+}
+
+.button-progress {
+  position: absolute;
+  top: calc(50% - 8px);
+  left: calc(50% - 8px);
+  display: none;
+  width: 16px;
+  height: 16px;
+  border: 2px solid rgba(17, 20, 8, 0.3);
+  border-top-color: var(--accent-text);
+  border-radius: 50%;
+  animation: spin 700ms linear infinite;
+}
+
+button:disabled .button-progress {
+  display: block;
+}
+
+.form-note {
+  margin: 12px 2px 0;
+  color: var(--quiet);
+  font-size: 12px;
+}
+
+.notice {
+  display: flex;
+  gap: 12px;
+  margin-top: 20px;
+  padding: 14px 16px;
+  color: #ffb4b4;
+  background: rgba(255, 107, 107, 0.07);
+  border: 1px solid rgba(255, 107, 107, 0.22);
+  border-radius: 10px;
+  font-size: 13px;
+}
+
+.notice-label {
+  flex: none;
+  color: var(--danger);
+  font-weight: 700;
+}
+
+.result {
+  padding: 72px 0 100px;
+  opacity: 0;
+  transform: translateY(12px);
+  transition: opacity 220ms ease, transform 220ms ease;
+}
+
+.result.is-visible {
+  opacity: 1;
+  transform: translateY(0);
+}
+
+.result.is-leaving {
+  opacity: 0;
+  transform: translateY(8px);
+}
+
+.result-heading {
+  display: flex;
+  gap: 24px;
+  align-items: flex-end;
+  justify-content: space-between;
+  padding: 58px 0 30px;
+}
+
+.result-heading .eyebrow,
+.formats-heading .eyebrow {
+  margin-bottom: 12px;
+}
+
+h2 {
+  max-width: 820px;
+  margin: 0;
+  font-size: clamp(28px, 4vw, 46px);
+  font-weight: 560;
+  letter-spacing: -0.04em;
+  line-height: 1.08;
+}
+
+.source-link {
+  flex: none;
+  padding-bottom: 3px;
+  color: var(--muted);
+  border-bottom: 1px solid var(--border-strong);
+  font-size: 12px;
+  text-decoration: none;
+}
+
+.result-actions {
+  display: flex;
+  flex: none;
+  gap: 18px;
+  align-items: center;
+}
+
+.text-button {
+  min-width: 0;
+  padding: 0 0 3px;
+  color: var(--muted);
+  font-size: 12px;
+  font-weight: 400;
+  background: transparent;
+  border-bottom: 1px solid var(--border-strong);
+  border-radius: 0;
+}
+
+.text-button:hover {
+  color: var(--text);
+  filter: none;
+}
+
+.source-link:hover {
+  color: var(--text);
+  border-color: var(--text);
+}
+
+.source-card {
+  display: grid;
+  grid-template-columns: minmax(300px, 0.85fr) minmax(380px, 1.15fr);
+  max-width: 920px;
+  overflow: hidden;
+  background: var(--surface);
+  border: 1px solid var(--border);
+  border-radius: var(--radius);
+}
+
+.thumbnail-shell {
+  position: relative;
+  aspect-ratio: 16 / 9;
+  overflow: hidden;
+  background: var(--surface-raised);
+}
+
+.thumbnail-shell img {
+  display: block;
+  width: 100%;
+  height: 100%;
+  object-fit: cover;
+}
+
+.thumbnail-shell.no-image::after {
+  position: absolute;
+  inset: 0;
+  display: grid;
+  place-items: center;
+  color: var(--quiet);
+  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
+  font-size: 11px;
+  letter-spacing: 0.1em;
+  content: "NO PREVIEW";
+}
+
+.duration {
+  position: absolute;
+  right: 12px;
+  bottom: 12px;
+  padding: 6px 8px;
+  color: var(--text);
+  background: rgba(9, 10, 12, 0.86);
+  border: 1px solid rgba(255, 255, 255, 0.12);
+  border-radius: 6px;
+  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
+  font-size: 11px;
+}
+
+.metadata {
+  display: grid;
+  grid-template-columns: 1fr 1fr;
+  margin: 0;
+  padding: 8px;
+}
+
+.metadata div {
+  min-width: 0;
+  padding: 18px 16px;
+  border-bottom: 1px solid var(--border);
+}
+
+.metadata div:nth-last-child(-n + 2) {
+  border-bottom: 0;
+}
+
+.metadata dt {
+  margin-bottom: 10px;
+  color: var(--quiet);
+  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
+  font-size: 10px;
+  letter-spacing: 0.1em;
+  text-transform: uppercase;
+}
+
+.metadata dd {
+  overflow: hidden;
+  margin: 0;
+  color: var(--text);
+  font-size: 14px;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
+
+.formats-heading {
+  display: flex;
+  align-items: end;
+  justify-content: space-between;
+  margin-top: 68px;
+}
+
+h3 {
+  margin: 0;
+  font-size: 26px;
+  font-weight: 570;
+  letter-spacing: -0.03em;
+}
+
+.formats-heading > p {
+  margin: 0 0 2px;
+  color: var(--quiet);
+  font-size: 12px;
+}
+
+.output-options {
+  display: grid;
+  grid-template-columns: 1fr 1fr;
+  gap: 14px;
+  margin-top: 22px;
+}
+
+.output-option {
+  display: grid;
+  grid-template-columns: auto 1fr;
+  gap: 22px;
+  padding: 24px;
+  background: var(--surface);
+  border: 1px solid var(--border);
+  border-radius: var(--radius);
+}
+
+.option-index {
+  color: var(--accent);
+  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
+  font-size: 10px;
+  font-weight: 700;
+  letter-spacing: 0.1em;
+}
+
+.option-copy h4 {
+  margin: 0;
+  font-size: 17px;
+  font-weight: 620;
+  letter-spacing: -0.02em;
+}
+
+.option-copy p {
+  max-width: 370px;
+  margin: 9px 0 0;
+  color: var(--muted);
+  font-size: 12px;
+  line-height: 1.6;
+}
+
+.option-specs {
+  display: flex;
+  grid-column: 1 / -1;
+  gap: 8px;
+  flex-wrap: wrap;
+  margin: 2px 0 0 32px;
+}
+
+.option-specs div {
+  display: inline-flex;
+  gap: 6px;
+  align-items: center;
+  padding: 7px 9px;
+  background: rgba(255, 255, 255, 0.025);
+  border: 1px solid var(--border);
+  border-radius: 7px;
+}
+
+.option-specs dt,
+.option-specs dd {
+  margin: 0;
+  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
+  font-size: 9px;
+}
+
+.option-specs dt {
+  color: var(--quiet);
+  text-transform: uppercase;
+}
+
+.option-specs dd {
+  color: var(--text);
+}
+
+footer {
+  display: flex;
+  justify-content: space-between;
+  padding: 24px 0 30px;
+  color: var(--quiet);
+  border-top: 1px solid var(--border);
+  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
+  font-size: 9px;
+  letter-spacing: 0.1em;
+  text-transform: uppercase;
+}
+
+.sr-only {
+  position: absolute;
+  width: 1px;
+  height: 1px;
+  padding: 0;
+  overflow: hidden;
+  clip: rect(0, 0, 0, 0);
+  white-space: nowrap;
+  border: 0;
+}
+
+[hidden] {
+  display: none !important;
+}
+
+@keyframes spin {
+  to {
+    transform: rotate(360deg);
+  }
+}
+
+@media (max-width: 760px) {
+  .site-header,
+  .page-shell,
+  footer {
+    width: min(100% - 28px, 1180px);
+  }
+
+  .hero {
+    padding: 72px 0 62px;
+  }
+
+  h1 {
+    font-size: clamp(40px, 13vw, 58px);
+  }
+
+  .input-shell {
+    grid-template-columns: 1fr;
+  }
+
+  button {
+    min-height: 48px;
+  }
+
+  .result-heading,
+  .formats-heading {
+    align-items: flex-start;
+    flex-direction: column;
+  }
+
+  .result-actions {
+    margin-top: -8px;
+  }
+
+  .source-card {
+    grid-template-columns: 1fr;
+  }
+
+  .output-options {
+    grid-template-columns: 1fr;
+  }
+
+  .metadata div {
+    padding: 20px 14px;
+  }
+
+  .formats-heading > p {
+    margin-top: -10px;
+  }
+}
+
+@media (prefers-reduced-motion: reduce) {
+  *,
+  *::before,
+  *::after {
+    scroll-behavior: auto !important;
+    transition-duration: 0.01ms !important;
+    animation-duration: 0.01ms !important;
+    animation-iteration-count: 1 !important;
+  }
+}
diff --git a/app/templates/index.html b/app/templates/index.html
new file mode 100644
index 0000000..28587e9
--- /dev/null
+++ b/app/templates/index.html
@@ -0,0 +1,128 @@
+<!doctype html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1">
+    <meta name="color-scheme" content="dark">
+    <meta name="theme-color" content="#0a0b0d">
+    <title>Media Ingest</title>
+    <link rel="stylesheet" href="{{ url_for('static', path='/styles.css') }}">
+    <script src="{{ url_for('static', path='/app.js') }}" defer></script>
+  </head>
+  <body>
+    <header class="site-header">
+      <a class="brand" href="/" aria-label="Media Ingest home">
+        <span class="brand-mark" aria-hidden="true"></span>
+        <span>Media Ingest</span>
+      </a>
+      <span class="environment">Local</span>
+    </header>
+
+    <main class="page-shell">
+      <section class="hero" aria-labelledby="page-title">
+        <p class="eyebrow">Source inspection</p>
+        <h1 id="page-title">Bring the source.<br>See what is available.</h1>
+        <p class="intro">
+          Inspect public video sources before choosing what enters your workflow.
+          Nothing is downloaded at this stage.
+        </p>
+
+        <form class="inspect-form" id="inspect-form">
+          <label class="sr-only" for="source-url">Public video URL</label>
+          <div class="input-shell">
+            <input
+              id="source-url"
+              name="url"
+              type="url"
+              inputmode="url"
+              autocomplete="url"
+              maxlength="2048"
+              placeholder="Paste a public video URL"
+              required
+            >
+            <button id="inspect-button" type="submit">
+              <span class="button-label">Inspect source</span>
+              <span class="button-progress" aria-hidden="true"></span>
+            </button>
+          </div>
+          <p class="form-note">HTTP and HTTPS sources only. Playlists are not supported.</p>
+        </form>
+
+        <div class="notice error-notice" id="error-notice" role="alert" hidden>
+          <span class="notice-label">Inspection failed</span>
+          <span id="error-message"></span>
+        </div>
+      </section>
+
+      <section class="result" id="result" aria-live="polite" hidden>
+        <div class="result-heading">
+          <div>
+            <p class="eyebrow">Source found</p>
+            <h2 id="result-title"></h2>
+          </div>
+          <div class="result-actions">
+            <button class="text-button" id="new-source" type="button">New source</button>
+            <a id="source-link" class="source-link" target="_blank" rel="noreferrer">Open source</a>
+          </div>
+        </div>
+
+        <div class="source-card">
+          <div class="thumbnail-shell" id="thumbnail-shell">
+            <img id="thumbnail" alt="" referrerpolicy="no-referrer">
+            <span class="duration" id="duration"></span>
+          </div>
+          <dl class="metadata">
+            <div>
+              <dt>Platform</dt>
+              <dd id="extractor"></dd>
+            </div>
+            <div>
+              <dt>Publisher</dt>
+              <dd id="uploader"></dd>
+            </div>
+            <div>
+              <dt>Published</dt>
+              <dd id="upload-date"></dd>
+            </div>
+            <div>
+              <dt>Top quality</dt>
+              <dd id="top-quality"></dd>
+            </div>
+          </dl>
+        </div>
+
+        <div class="formats-heading">
+          <div>
+            <p class="eyebrow">Output choices</p>
+            <h3>Choose the outcome</h3>
+          </div>
+          <p>Technical stream selection happens automatically.</p>
+        </div>
+
+        <div class="output-options" id="output-options">
+          <article class="output-option" id="best-option">
+            <div class="option-index">01</div>
+            <div class="option-copy">
+              <h4>Best available</h4>
+              <p>Keep the highest source quality. Container and codec may vary.</p>
+            </div>
+            <dl class="option-specs" id="best-specs"></dl>
+          </article>
+          <article class="output-option" id="compatible-option">
+            <div class="option-index">02</div>
+            <div class="option-copy">
+              <h4>Compatible MP4</h4>
+              <p>Prefer H.264 video and AAC audio for editing and playback.</p>
+            </div>
+            <dl class="option-specs" id="compatible-specs"></dl>
+          </article>
+        </div>
+      </section>
+    </main>
+
+    <footer>
+      <span>Private media workflow</span>
+      <span>Inspection only</span>
+    </footer>
+  </body>
+</html>
diff --git a/docs/ARCHITECTURE.md b/docs/ARCHITECTURE.md
new file mode 100644
index 0000000..b9e64d8
--- /dev/null
+++ b/docs/ARCHITECTURE.md
@@ -0,0 +1,48 @@
+# Architecture
+
+## Current state
+
+```text
+Browser
+  -> FastAPI / Jinja interface
+  -> POST /api/inspect
+  -> URL validation
+  -> yt-dlp metadata extraction (download disabled)
+  -> normalized metadata and output previews
+```
+
+FastAPI runs inspection in a thread pool. The browser receives a deliberately
+small response and never receives yt-dlp's signed media URLs. Displayed output
+options are previews; backend download selectors are not implemented yet.
+
+## Next application boundary
+
+Downloads will use durable jobs rather than long-running HTTP requests:
+
+```text
+Web service -> SQLite job record <- Worker service
+                                     |
+                                     +-> yt-dlp
+                                     +-> FFmpeg / ffprobe
+                                     +-> per-job directory
+```
+
+The worker will claim one queued job at a time, update progress, validate the
+finished media, and record the artifact. This preserves state across web
+restarts and keeps media processing outside request handlers.
+
+## Planned output presets
+
+1. **Best available** — highest useful source quality, merging separate video
+   and audio streams without transcoding.
+2. **Compatible MP4** — prefer the highest H.264 video and AAC audio streams
+   that can be merged into MP4 without transcoding.
+
+If no compatible combination exists, the first version should report that
+instead of silently starting an expensive transcode. Transcoding can later be
+an explicit third outcome with CPU and time limits.
+
+## Production boundary
+
+Production will route Cloudflare Access through Cloudflare Tunnel to the web
+service. The origin will not publish an application port directly.
diff --git a/docs/SECURITY.md b/docs/SECURITY.md
new file mode 100644
index 0000000..ca06523
--- /dev/null
+++ b/docs/SECURITY.md
@@ -0,0 +1,63 @@
+# Security
+
+## Trust model
+
+The submitted URL and all remote metadata are untrusted. yt-dlp and FFmpeg
+process attacker-controlled network content and must not have host privileges
+or access to unrelated files and services. The current development build is
+not ready for public exposure.
+
+## Controls currently implemented
+
+- port bound only to `127.0.0.1`
+- non-root, read-only container with a small `/tmp` tmpfs
+- all Linux capabilities dropped and `no-new-privileges` enabled
+- yt-dlp plugins disabled and configuration files ignored
+- inspection only; media download disabled
+- playlists and multi-video results rejected
+- only HTTP/HTTPS URLs on ports 80/443 accepted
+- URL credentials rejected
+- initially resolved IPv4 and IPv6 addresses must all be globally routable
+- raw signed media URLs omitted from API responses
+- remote metadata inserted into the interface as text, not HTML
+
+## Required before download jobs
+
+- maximum source duration and estimated output size
+- per-job timeout and cancellation
+- one concurrent worker job initially
+- bounded CPU, memory, process, and temporary-storage use
+- randomized job directories and server-generated filenames
+- no user-controlled output templates or command fragments
+- FFmpeg/ffprobe validation of completed artifacts
+- safe handling of partial files and failed merges
+- automatic expiry and deletion
+- durable job recovery after process or container restarts
+- logs that exclude signed URLs, cookies, and credentials
+
+## Required before Internet deployment
+
+- Cloudflare Access deny-by-default policy
+- Cloudflare Tunnel with Access-token validation at the origin
+- no directly reachable origin application port
+- request-rate and body-size limits
+- explicit production configuration validation
+- dependency and container-image update procedure
+
+## SSRF limitation
+
+Initial-host validation is necessary but incomplete. Extractors may follow
+redirects and retrieve manifests, APIs, or media from additional hosts. DNS
+answers can also change between validation and connection.
+
+Before Internet deployment, outbound traffic from the processing service must
+be restricted at the network layer so private, loopback, link-local, multicast,
+and infrastructure-metadata destinations cannot be reached. URL validation is
+an additional layer, not the sole SSRF defense.
+
+## Deferred features
+
+Browser cookies and authenticated source accounts are excluded. A cookie file
+is effectively an account credential. Supporting one requires encrypted secret
+handling, isolated injection, redacted logging, rotation, and a deliberate
+account-compromise risk review.
diff --git a/requirements.txt b/requirements.txt
index a04939a..593ff0a 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,3 +1,4 @@
 fastapi==0.139.2
+jinja2==3.1.6
 uvicorn==0.51.0
 yt-dlp==2026.6.9
diff --git a/tests/test_health.py b/tests/test_health.py
index 559f9a7..60942b5 100644
--- a/tests/test_health.py
+++ b/tests/test_health.py
@@ -12,8 +12,18 @@ def test_health_returns_healthy() -> None:
     assert response.json() == {"status": "healthy"}
 
 
-def test_root_identifies_application() -> None:
+def test_root_renders_interface() -> None:
     response = client.get("/")
 
     assert response.status_code == 200
-    assert response.json() == {"name": "Media Ingest", "status": "running"}
+    assert response.headers["content-type"].startswith("text/html")
+    assert "Media Ingest" in response.text
+    assert 'id="inspect-form"' in response.text
+    assert 'id="new-source"' in response.text
+
+
+def test_static_styles_are_served() -> None:
+    response = client.get("/static/styles.css")
+
+    assert response.status_code == 200
+    assert "--background" in response.text